WO2012020045A1

WO2012020045A1 - Method for selecting patients with stable coronary artery disease for pci or medical treatment

Info

Publication number: WO2012020045A1
Application number: PCT/EP2011/063750
Authority: WO
Inventors: Georg Hess; Dietmar Zdunek; Andrea Horsch
Original assignee: Roche Diagnostics Gmbh; F. Hoffmann-La Roche Ag
Priority date: 2010-08-10
Filing date: 2011-08-10
Publication date: 2012-02-16

Abstract

The present invention relates to means and methods for the selection of patients who are susceptible to percutaneous coronary intervention (PCI) or a bypass of at least one large coronary artery. Specifically, the method of the present invention is based on the determination of the amounts of a cardiac troponin or a variant thereof and/or a natriuretic peptide in a sample of a patient.

Description

Method for selecting patients with stable coronary artery disease for PCI or medical treatment

Percutaneous coronary intervention (PCI) represents an important therapeutic option for the treatment of stable coronary artery disease. Medical treatment with ACE-inhibitors, angiotensin receptor inhibitors, beta-blockers and optionally diuretics is another treatment option. Alternatively, saphenous veins can be used to bypass occluded parts of the large coronary arteries. For patients who are not eligible for PCI, medical treatment is used as an alternative treatment. Patients who are eligible for PCI may receive medical treatment in addition to PCI. Studies have indicated that PCI is not superior to medical treatment in terms of survival but frequently ameliorates symptoms (Boden W.E. et al, NEJM 2007, 356, 1503). Therefore optimal selection of patients is required. A patient who is unlikely to benefit from PCI should be spared the risk and the stress associated with this intervention. When selecting the course of treatment the following considerations are taken into account: need for mechanical revascularisation or bypass of the large coronary arteries, likelihood of successful intervention, risks, likelihood of restenosis, need for revascularisation and finally comorbidities and patient choice (for details see Morrow D.A. and Gersh B.J. in Braunwald's Heart Disease, 8. Ed. Chapter 54). PCI is the optimal treatment for patients with moderate to severe angina but not for those with mild symptoms. The latter are best treated with medication (Popma J.J. et al, Chapter 55 in Braunwald^'s Heart disease 8. Ed.).

The majority of PCI, approximately 90%, are associated with the implantation of STENTs. STENTs are tubes, usually made from metal, that are placed in a coronary artery that has been reopened by inflating a balloon at the tip the catheter. STENTS provide a mechanical framework for the opened artery and, thus, stabilize its new shape. However, bare metal STENTS may be subject to STENT thrombosis, i.e. the metal may induce the aggregation of platelets that occlude the artery to a smaller or larger extent. Since PCI aims at the restoration blood flow through a coronary artery, this effect is not desirable. Therefore bare metal STENTS have been partly replaced by drug eluting STENTs which are believed to prevent early STENT thrombosis (for details see Popma et al.).

During STENT implantation the vessel is closed with a balloon for seconds or minutes, this is followed by the application of a STENT to open the coronary artery at the stenosis site. This procedure is, however, not without side effects. Thrombotic or plaque material is frequently released during the procedure and embolized into distant vessels causing PCI- associated myocardial infarction. Using Troponin I and an increase of Troponin three times the 99^th percentile of normal reference values has identified that 23.4 percent of the patients treated with PCI suffer from myocardial infarction related to PCI (Am. J. Cardiol. 2009, 103, 639 - 645). Other complications of angiography with and without STENT implantation include dissections (which occur in 1.7% of patients) and coronary perforation with a frequency of 0.2. - 0.5%. Finally STENT implantation may be associated with early (predominantly bare metal STENT) or late (drug eluting STENT) STENT thrombosis. Moreover patients with STENTS require antiplatelet drugs known to be associated with bleeding risks (Popma et al in Braunwalds Heart Disease). It was shown previously by using sensitive troponin T tests that troponin T levels were associated with the extent of coronary artery disease (EP 071 14174.1/ 1 890 154 ). Because on the one hand PCI is associated with a significant risk of myocardial infarction, and on the other hand not every patient is likely to benefit from PCI, the decision about performing PCI in a patient has to be made very carefully. PCI should only performed in patients where the aforementioned risk of PCI is compensated by benefits for the patient. This requires the assessment of the individual patient's prospects of benefiting from PCI. Thus, the technical problem underlying the present invention could be seen as the provision of means and methods that allow a decision about the treatment of an individual patient with either PCI or medical treatment or a combination of both.

The technical problem is solved by the embodiments characterized in the claims and herein below.

The present invention relates to a method for selecting a patient susceptible to percutaneous coronary intervention (PCI) based on the determination of the amount of a natriuretic peptide and/or a cardiac troponin in a sample of the patient and the comparison of the determined amount or amounts with a reference amount or reference amounts.

It is also provided for a method for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the respective biomarker to a reference amount; wherein the patient susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery is selected based on the results obtained in step b).

Preferably, the method of the present invention comprises at least one of the following steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the respective biomarker to a reference amount; and c) deciding whether the patient is susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery.

Accordingly the present invention relates to a method for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the respective biomarker to a reference amount; and

c) deciding whether the patient is susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery.

The method of the present invention is, preferably, an in vitro method. Moreover, it may comprise steps in addition to those explicitly mentioned above including sample pre- treatments or evaluation of the results obtained by the method. The method may be carried out manually and/or assisted by automation. Preferably, steps (a), (b) and/or (c) may in total or in part be assisted by automation including suitable robotic and sensory equipment for the determination in step (a) and/or a computer-implemented comparison under steps (b) and/or (c).

The term "sample" refers to a sample of a body fluid, to a sample of separated cells or to a sample from a tissue or an organ. Samples of body fluids can be obtained by well known techniques and include, preferably, samples of blood, plasma, serum, or urine, more preferably, samples of blood, plasma or serum. Tissue or organ samples may be obtained from any tissue or organ by, e.g., biopsy. Separated cells may be obtained from the body fluids or the tissues or organs by separating techniques such as centrifugation or cell sorting. Preferably, cell-, tissue- or organ samples are obtained from those cells, tissues or organs which express or produce the peptides referred to herein.

The patient is, preferably, a human. Preferably, the patient suffers or is suspected to suffer from coronary artery disease. Most preferably, the patient is stable, i.e. he does not suffer from an acute cardiovascular event, e.g. unstable angina pectoris or a myocardial infarction (both disorders are also referred to as "acute coronary syndrome"). Coronary artery disease results from the deposition of atheromatous plaque in the coronary arteries. Said plaque comprises macrophages, cholesterol crystals and microcalcifications. The deposition of atheromatous plaque leads to a stenosis of the affected vessel. Depending on the extent of the stenosis, the blood flow through the vessel is impaired and those parts of the myocardium that depend on this artery for their supply of oxygen suffer from insufficient oxygen supply (ischemia). Clinically, this condition leads to angina pectoris, i.e. chest pain. The decreased oxygen supply may also lead to a functional impairment of the affected part of the myocardium, thus decreasing the contractile force of the myocardium. Moreover, coronary artery disease increases the patient^'s risk for acute cardiovascular events including myocardial infarction, cardiac dysrhythmia, heart failure and sudden cardiac death.

If an atherosclerotic lesion occludes at least 50% of the lumen of a coronary artery, this condition is defined as 1 -vessel disease. The occlusion of two or three major coronary arteries by at least 50% is defined as 2- or 3-vessel disease. More preferably, the patient suffers from 1 -vessel disease, 2-vessel disease or 3-vessel disease. The number of stenoses in a specific vessel does not affect the definition of vessel disease.

The patient may also suffer from diffuse multi-vessel disease. In this condition no occlusion of the major coronary arteries meets the criteria set forth above for 1-, 2- or 3- vessel disease. The occlusions rather affect minor arteries, nevertheless resulting in ischemia in at least parts of the myocardium.

The patient may also suffer from heart failure. Clinically, a coronary heart disease leads, preferably, to heart failure. Heart failure is characterized by the inability of the heart to pump that volume of blood which is required to fulfill the oxygen demand of the body. The severity of heart failure can be classified according to clinical findings according to the guidelines by the New York Heart Association (NYHA).

Class I heart failure is characterized by the presence of cardiac disease without symptoms of heart failure, i.e. no limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitations, dyspnea, or angina pain.

Class II heart failure is characterized by slight limitation of physical activity. The patient is comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or angina pain.

Class III heart failure is characterized by marked limitations of physical activity. The patient is comfortable at rest. Less than ordinary physical activity results in fatigue, palpitation, dyspnea, or angina pain.

Class IV heart failure is characterized by the inability to carry out any physical activity without discomfort. Symptoms of heart failure or the angina syndrome may be present even at rest. If any physical activity is undertaken, the discomfort increases.

Preferably, the patient is stable, i.e. the condition of the patient does no deteriorate or improve suddenly. Thus, the patient may suffer from stable angina pectoris but not from unstable angina pectoris or even myocardial infarction. Chest discomfort in stable angina pectoris is precipitated by activity such as running or walking. It abates some minutes after cessation of the activity. The intensity of discomfort does not increase. Unstable angina pectoris is characterized by a least one of the following features: (i) chest pain at rest, (ii) new onset of chest discomfort and (iii) increasing duration, frequency and/or severity of chest discomfort. Moreover, the patient has, preferably, normal kidney function as defined by a glomerular filtration rate of more than 60 ml per minute and 1.73 m² body surface or by a serum creatinine value lower than 1.3 mg/dl. More preferably, the patient suffers from stable coronary artery disease, i.e. he/she did not suffer from acute cardiovascular events, i.e. instable angina pectoris, myocardial infarction with ST-element elevation or myocardial infarction without ST-element elevation within at least about 1 week, within at least about 2 weeks, within at least about 3 weeks or within at least about 4 weeks prior to sampling. Most preferably, the patient did not suffer from an acute cardiovascular event within 2 weeks before sampling.

Furthermore preferably, the patient did not experience chest pain within about one week or about two weeks, more preferably within about one week, prior to taking the sample. Coronary artery disease can be treated by medical treatment, by bypass of at least one large coronary artery, by bypass of small coronary vessels or by percutaneous coronary intervention (PCI).

Medical treatment of coronary heart disease, preferably, includes the administration of ACE-inhibitors, angiotensin receptor inhibitors, beta-blockers and optionally diuretics. This mode of therapy is especially preferred if the patient suffers from heart failure in addition to coronary heart disease.

Medical treatment of stable angina pectoris as a consequence of coronary heart disease, preferably, includes treatment with nitrates. If angina pectoris is accompanied by cardiac arrhythmia or conduction disturbances, nifedipine, amlodipine or beta blockers are, preferably administered additionally. If angina pectoris is accompanied by claudication or severe depression, calcium channel blockers may be administered. The preferred medical treatment for the prevention of thrombosis is antiplatelet therapy. Preferred agents for antiplatelet therapy are irreversible nonsteroidal anti-inflammatory drugs, preferably aspirin, ADP-inhibitors, preferably clopidogrel, prasugrel and cangrelor, phosphodiesterase inhibitors, preferably, dipyridamole and cilostazol and, less preferably glycoprotein Ilb/IIa antagonists such as abciximab, eptifibatide and tirofiban. Nitrates are prodrugs that release nitric oxide (NO). NO induces a relaxation of the vessels and, thus, decreases the preload of the heart. Preferred nitrates are nitroglycerin (also known as glyceryl trinitrate), isosorbide dinitrate and isosorbide mononitrate. Beta blockers bind to the β-receptors. Different subclasses of this receptor are present in the myocardium, in the kidney, in the lung, in skeletal muscle, in smooth muscle, in the gastrointestinal tract, in the liver and the uterus. Beta blockers decrease heart rate and the force of cardiac contractions by inhibiting the stimulation of β-adrenergic receptors, preferably, βι-adrenergic receptors. Cardiac work load and oxygen demand are consequently decreased. Preferred beta blockers are acebutolol, betaxolol, bisoprolol, esmolol, propranolol, atenolol, labetalol, carvedilol, metoprolol, and nebivolol.

Calcium channel blockers act on the voltage-gated calcium channels in the sarcoplasmatic reticulum of cardiomyocytes and smooth muscle cells. They inhibit the release of calcium from these intracellular stores upon activation of the muscle. Because the released calcium mediates the contraction of the muscle, decreased cytosolic calcium concentrations lead to a decreased contractile force of the muscle. The resulting relaxation of the smooth muscles lining the peripheral arteries leads to vasodilation, thus reducing the afterload of the heart. Preferred calcium channel blockers are dihydropyridines, phenylalkyamines and benzothiazepines.

Preferred ACE-inhibitors are captopril, enalapril, fosinopril, lisinopril, perindopril, quinapril, ramipril, or trandolapril. The term "percutaneous coronary intervention" (or "PCI") is well known to the person skilled in the art. Briefly, a catheter with a deflated balloon at its tip is introduced into the coronary artery through the femoral artery of the leg. The catheter is then guided to the location of the stenosis. At the point of the stenosis the balloon is inflated thus compressing the atheromateous plaque and simultaneously stretching the flexible wall of the affected vessel. To prevent restenosis it is possible to introduce a wire mesh tube (a "STENT") into the vessel. The STENT may be a drug-eluting stent releasing pharmaceuticals that further reduce the risk of restenosis. Suitable pharmaceuticals are those that inhibit tissue growth. Preferably, the term "PCI" also encompasses introduction of a stent. The term„bypass of at least one large coronary artery" refers to a bypass of at least one of the following major coronary vessels. Major coronary vessels are, preferably the right coronary artery, the left coronary artery, the left circumflex artery and the left anterior descending artery. Preferably, the bypass is formed using a saphenous vein.

Although small arteries and smaller subpericardial arteries are, preferably, not subject to bypass surgery, local blood supply can be increased by the linking an artery not regularly supplying the heart to the apex of the heart, thus linking this artery to coronary vessels in areas of reduced blood supply located at the apex of the heart. Preferably, the Arteria thoracica is used for this purpose. In the present application, this bypass is referred to as "bypass of small coronary vessels".

In a patient who is "susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery" the expected benefits of PCI or bypass of at least one large coronary artery outweigh the risks associated with PCI. As set forth above, myocardial infarction (MI) may be an undesired consequence of PCI. MI is, hence, a risk that is associated with PCI. Preferably, an increased risk of MI indicates that a patient is not susceptible to PCI. The expected benefit of PCI is the improvement of blood-flow through the vessel treated with PCI. Ischemia of the myocardium is reduced as a consequence of the improved blood flow. Therefore, the expected benefits of PCI are, preferably, increased blood flow through the treated coronary artery, increased oxygen supply of at least a part of the myocardium, decrease of the frequency and severity of bouts of angina pectoris, decrease of the extent of myocardial necrosis and a decreased risk of acute cardiovascular events. As ischemia may lead to decreased myocardial function without tissue damage, also known as "hibernation" of the myocardium, the restoration of myocardial function is also a benefit of PCI. More preferably, the benefit of PCI is the decrease of myocardial necrosis. Preferably, the method of the present invention allows the prognosis of the benefits of PCI in a patient.

The risks of bypass of at least one large coronary artery include postperfusion syndrome, nonunion of the sternum, myocardial infarction due to hypoperfusion, embolism, or graft failure, vasoplegic syndrome, acute renal failure due to embolism or hypoperfusion, pneumothorax, hemothorax, pericardial tamponade, infection and sepsis, deep vein thrombosis and perioperative death. Thus, the term "selecting a patient susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery" refers to the process of dividing a group of patients into those who are likely to benefit from PCI or bypass of at least one large coronary artery and those who likely will not benefit from said treatment. The term also encompasses the process of identifying patients likely to benefit from PCI or bypass of at least one large coronary artery and/or the process of identifying patients likely not to benefit from PCI or bypass of at least one large coronary artery.

In the context of the present invention, the benefits of PCI or bypass of at least one large coronary artery are, preferably, determined based on the comparison of the amounts of a cardiac troponin in samples taken from the same patient before and after PCI. A decrease of the amount of the cardiac troponin in a sample taken after PCI as compared to the amount in a sample taken before PCI or implantation of the bypass of at least one large coronary artery, preferably, indicates that PCI was successful, i.e. that the patient was susceptible to PCI or bypass of at least one large coronary artery. The second sample is, preferably, taken at least about 1 month, at least about 2 months or at least about 3 months after PCI or bypass of at least one large coronary artery is performed. The term "about" in this context refers to +/- 5% of a given measurement. Also preferably, increased cardiac function due to improved oxygen supply is a benefit of PCI or bypass of at least one large coronary artery.

Because cardiac troponins are released by cardiomyocytes as a consequence of cell death, the increase or decrease of the amounts of cardiac troponins in samples taken after PCI or implantation of the bypass of at least one large coronary artery as compared to samples taken from the same patient before PCI or implantation of the bypass of at least one large coronary artery indicates the success of PCI or bypass of at least one large coronary artery. Preferably, a decrease of the amount of a cardiac troponin after PCI or bypass of at least one large coronary artery indicates that the oxygen supply of the myocardium has been improved leading to a smaller extent of ischemia and, thus, cardiomyocyte death. In a patient who benefits from PCI or bypass of at least one large coronary artery the amount of a cardiac troponin decreases after PCI is performed or the bypass of at least one large coronary artery is implanted. The decrease of the amount of the cardiac troponin in the sample taken after PCI or bypass of at least one large coronary artery as compared to the amount determined in a sample taken before PCI or bypass of at least one large coronary artery is, preferably, statistically significant. Whether a portion is statistically significant can be determined without further ado by the person skilled in the art using various well known statistic evaluation tools, e.g., determination of confidence intervals, p-value determination, Student^'s t-test, Mann- Whitney test, etc.. Details are found in Dowdy and Wearden, Statistics for Research, John Wiley & Sons, New York 1983. Preferred confidence intervals are at least 90%, at least 95%, at least 97%, at least 98% or at least 99%. The p-values are, preferably, 0.1 , 0.05, 0.01 , 0.005, or 0.0001.

More preferably, a decrease of the amount of the cardiac troponin of at least about 15% at least about 20%, at least about 25%> or at least about 30% after PCI or bypass of at least one large coronary artery relative to the baseline level, i.e. a level of cardiac troponin determined before the PCI or implantation of the bypass of at least one large coronary artery, indicates successful PCI. Most preferably, the decrease of the amount of the cardiac troponin in the sample taken after PCI or implantation of the bypass of at least one large coronary artery is at least about 20%. (see example 2) The term "about" in this context refers to +/- 5% of a given measurement.

The term "natriuretic peptide" comprises Atrial Natriuretic Peptide (ANP)-type and Brain Natriuretic Peptide (BNP)-type peptides and variants thereof having the same predictive potential. Natriuretic peptides according to the present invention comprise ANP-type and BNP-type peptides and variants thereof (see e.g. Bonow, 1996, Circulation 93: 1946- 1950). ANP-type peptides comprise pre-proANP, proANP, NT-proANP, and ANP. BNP- type peptides comprise pre-proBNP, proBNP, NT-proBNP, and BNP. The pre-pro peptide (134 amino acids in the case of pre-proBNP) comprises a short signal peptide, which is enzymatically cleaved off to release the pro peptide (108 amino acids in the case of proBNP). The pro peptide is further cleaved into an N-terminal pro peptide (NT-pro peptide, 76 amino acids in case of NT-proBNP) and the active hormone (32 amino acids in the case of BNP, 28 amino acids in the case of ANP). ANP and BNP have a vasodilatory effect and cause excretion of water and sodium via the urinary tract. Preferably, natriuretic peptides according to the present invention are NT-proANP, ANP, and, more preferably, NT-proBNP, BNP, and variants thereof. ANP and BNP are the active hormones and have a shorter half-life than their respective inactive counterparts, NT-proANP and NT-proBNP. BNP is metabolized in the blood, whereas NT-proBNP circulates in the blood as an intact molecule and as such is eliminated renally. The in-vivo half-life of NT-pro BNP is 120 min longer than that of BNP, which is 20 min (Smith 2000, J Endocrinol. 167: 239-46.). Preanalytics are more robust with NT-proBNP allowing easy transportation of the sample to a central laboratory (Mueller 2004, Clin Chem Lab Med 42: 942-4.). Blood samples can be stored at room temperature for several days or may be mailed or shipped without recovery loss. In contrast, storage of BNP for 48 hours at room temperature or at 4° Celsius leads to a concentration loss of at least 20 % (Mueller loc.cit; Wu 2004, Clin Chem 50: 867-73.). Therefore, depending on the time-course or properties of interest, either measurement of the active or the inactive forms of the natriuretic peptide can be advantageous.

The most preferred natriuretic peptides according to the present invention are NT-proBNP or variants thereof. As briefly discussed above, the human NT-proBNP, as referred to in accordance with the present invention, is a polypeptide comprising, preferably, 76 amino acids in length corresponding to the N-terminal portion of the human NT-proBNP molecule. The structure of the human BNP and NT-proBNP has been described already in detail in the prior art, e.g., WO 02/089657, WO 02/083913 or Bonow loc. cit. Preferably, human NT-proBNP as used herein is human NT-proBNP as disclosed in EP 0 648 228 Bl . These prior art documents are herewith incorporated by reference with respect to the specific sequences of NT-proBNP and variants thereof disclosed therein. Biological and/or immunological NT-proBNP properties can be detected by the assay described in Karl et al. (Karl 1999, Scand J Clin Invest 230:177-181), Yeo et al. (Yeo 2003, Clinica Chimica Acta 338: 107-1 15).

The term "cardiac Troponin" refers to all Troponin isoforms or variants thereof expressed in cells of the heart and, preferably, the subendocardial cells. These isoforms are well characterized in the art as described, e.g., in Anderson 1995, Circulation Research, vol. 76, no. 4: 681 -686 and Ferrieres 1998, Clinical Chemistry, 44: 487-493. Preferably, cardiac Troponin refers to Troponin T and/or Troponin I, and, most preferably, to Troponin T. It is to be understood that isoforms of Troponins may be determined in the method of the present invention together, i.e. simultaneously or sequentially, or individually, i.e. without determining the other isoform at all. Amino acid sequences for human Troponin T and human Troponin I are disclosed in Anderson, loc cit and Ferrieres 1998, Clinical Chemistry, 44: 487-493. Preferably the biological property of troponin 1 and its variant is the ability to inhibit actomyosin ATPase or to inhibit angiogenesis in vivo and in vitro, which may e.g. be detected based on the assay described by Moses et al. 1999 PNAS USA 96 (6): 2645- 2650). Preferably the biological property of troponin T and its variant is the ability to form a complex with troponin C and I, to bind calcium ions or to bind to tropomyosin, preferably if present as a complex of troponin C, 1 and T or a complex formed by troponin C, troponin I and a variant of troponin T. The term "Growth-Differentiation Factor- 15" or "GDF-15" relates to a polypeptide being a member of the transforming growth factor (TGF)-P cytokine superfamily, The terms polypeptide, peptide and protein are used interchangeable throughout this specification. GDF-1 5 was originally cloned as macrophage-inhibitory cytokine- 1 and later also identified as placental transforming growth factor- β, placental bone morphogenetic protein, non-steroidal anti-inflammatory drug-activated gene-1 , and prostate-derived factor (Bootcov loc cit; Hromas, 1997 Biochim Biophys Acta 1354:40-44; Lawton 1997, Gene 203:17-26; Yokoyama- obayashi 1997, J Biochem (Tokyo), 122:622-626; Paralkar 1998, J Biol Chem 273: 13760-13767). Similar to other TGF-p-related cytokines, GDF-15 is synthesized as an inactive precursor protein, which undergoes disulfide-linked homodimerization. Upon proteolytic cleavage of the N-terminal pro-peptide, GDF-15 is secreted as a -28 kDa dimeric protein (Bauskin 2000, Embo J 19:2212-2220). Amino acid sequences for GDF- 15 are disclosed in WO99/06445, WO00/70051 , WO2005/1 13585, Bottner 1999, Gene 237: 105-1 11, Bootcov loc. cit, Tan loc. cit., Baek 2001 , Mol Pharmacol 59: 901 -908, Hromas loc cit, Paralkar loc cit, Morrish 1996, Placenta 17:431 - 441 or Yokoyama-Kobayashi loc cit.. A preferred GDF-15 assay in the context of the present invention a sandwich immuno-assay using a COBAS analyser from HTACHI- ROCHE. The assay contains antibodies obtained from R & D systems, Minneapolis, USA and the test is adopted to the assay described by Wollert et al in Clinical Chemistry 53, 2, 284 - 291, 2007. The biological functions of GDF-15 are highly dependent on cell type and context. In the context of cardiac disease, GDF-15 has been shown to protect cardiomyocytes from ischemia/reperfusion injury (Kempf et al., 2006, Circulation Research, 98: 351-360). In the context of cancer the overexpression of GDF-15 in vitro has been shown to increase the motility of cancer cell lines (Senapatis, S. et al., 2010, Oncogene, 29: 1293-1302). The term "variant" encompasses also variants of the specific peptides of the present application. Such variants have at least the same essential biological and immunological properties as the specific cardiac Troponins and natriuretic peptides. In particular, they share the same essential biological and immunological properties if they are detectable by the same specific assays referred to in this specification, e.g., by ELISA Assays using polyclonal or monoclonal antibodies specifically recognizing the said cardiac Troponins and natriuretic peptides. Moreover, it is to be understood that a variant as referred to in accordance with the present invention shall have an amino acid sequence which differs due to at least one amino acid substitution, deletion and/or addition wherein the amino acid sequence of the variant is still, preferably, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 85%, at least about 90%, at least about 92%, at least about 95%o, at least about 97%, at least about 98%, or at least about 99% identical with the amino sequence of the specific Troponin or natriuretic peptide, preferably over the entire length of the specific peptide. Variants may be allelic variants or any other species specific homologs, paralogs, or orthologs. Moreover, the variants referred to herein include fragments of the specific cardiac Troponins or natriuretic peptides or the aforementioned types of variants as long as these fragments have the essential immunological and biological properties as referred to above. Preferably, the NT-proBNP variants have immunological properties (i.e. epitope composition) comparable to those of NT-proBNP. Thus, the variants shall be recognizable by the aforementioned means or ligands used for determination of the amount of the natriuretic peptides. Biological and/or immunological NT-proBNP properties can be detected by the assay described in Karl et al. (Karl 1999, Scand J Clin Invest 230: 177-181 ), Yeo et al. (Yeo 2003, Clinica Chimica Acta 338:107- 1 15). Preferably the biological property of troponin I and its variant is the ability to inhibit actomyosin ATPase or to inhibit angiogenesis in vivo and in vitro, which may e.g. be detected based on the assay described by Moses et al. 1999 PNAS USA 96 (6): 2645- 2650). Preferably the biological property of troponin T and its variant is the ability to form a complex with troponin C and I, to bind calcium ions or to bind to tropomyosin, preferably if present as a complex of troponin C, I and T or a complex formed by troponin C, troponin I and a variant of troponin T. Thus, the variants shall be recognizable by the aforementioned means or ligands used for determination of the amount of the cardiac troponins or natriuretic peptides. Such fragments may be, e.g., degradation products of the peptides of the present invention. Further included are variants which differ due to posttranslational modifications such as phosphorylation or myristylation. Determining the amount of a natriuretic peptide, preferably NT-proBNP, or the amount of a cardiac troponin, preferably troponin T, or any other peptide or polypeptide or protein referred to in this specification relates to measuring the amount or concentration, preferably semi-quantitatively or quantitatively. The terms polypeptide and protein are used interchangeable throughout this application. Measuring can be done directly or indirectly. Direct measuring relates to measuring the amount or concentration of the peptide or polypeptide based on a signal which is obtained from the peptide or polypeptide itself and the intensity of which directly correlates with the number of molecules of the peptide present in the sample. Such a signal - sometimes referred to herein as intensity signal - may be obtained, e.g., by measuring an intensity value of a specific physical or chemical property of the peptide or polypeptide. Indirect measuring includes measuring of a signal obtained from a secondary component (i.e. a component not being the peptide or polypeptide itself) or a biological read out system, e.g., measurable cellular responses, ligands, labels, or enzymatic reaction products.

In accordance with the present invention, determining the amount of a peptide or polypeptide can be achieved by all known means for determining the amount of a peptide in a sample. Said means comprise immunoassay devices and methods which may utilize labelled molecules in various sandwich, competition, or other assay formats. Said assays will develop a signal which is indicative for the presence or absence of the peptide or polypeptide. Moreover, the signal strength can, preferably, be correlated directly or indirectly (e.g. reverse- proportional) to the amount of polypeptide present in a sample. Further suitable methods comprise measuring a physical or chemical property specific for the peptide or polypeptide such as its precise molecular mass or NMR spectrum. Said methods comprise, preferably, biosensors, optical devices coupled to immunoassays, biochips, analytical devices such as mass- spectrometers, NMR- analyzers, or chromatography devices. Further, methods include micro-plate ELISA-based methods, fully-automated or robotic immunoassays (available for example on ElecsysTM analyzers), CBA (an enzymatic Cobalt Binding Assay, available for example on Roche-HitachiTM analyzers), and latex agglutination assays (available for example on Roche-HitachiTM analyzers).

Preferably, determining the amount of a peptide or polypeptide comprises the steps of (a) contacting a cell capable of eliciting a cellular response the intensity of which is indicative of the amount of the peptide or polypeptide with the said peptide or polypeptide for an adequate period of time, (b) measuring the cellular response. For measuring cellular responses, the sample or processed sample is, preferably, added to a cell culture and an internal or external cellular response is measured. The cellular response may include the measurable expression of a reporter gene or the secretion of a substance, e.g. a peptide, polypeptide, or a small molecule. The expression or substance shall generate an intensity signal which correlates to the amount of the peptide or polypeptide.

Also preferably, determining the amount of a peptide or polypeptide comprises the step of measuring a specific intensity signal obtainable from the peptide or polypeptide in the sample. As described above, such a signal may be the signal intensity observed at an m/z variable specific for the peptide or polypeptide observed in mass spectra or a NMR spectrum specific for the peptide or polypeptide.

Determining the amount of a peptide or polypeptide may, preferably, comprise the steps of (a) contacting the peptide with a specific ligand, (b) (optionally) removing non-bound ligand, (c) measuring the amount of bound ligand. The bound ligand will generate an intensity signal. Binding according to the present invention includes both covalent and non-covalent binding. A ligand according to the present invention can be any compound, e.g., a peptide, polypeptide, nucleic acid, or small molecule, binding to the peptide or polypeptide described herein. Preferred ligands include antibodies, nucleic acids, peptides or polypeptides such as receptors or binding partners for the peptide or polypeptide and fragments thereof comprising the binding domains for the peptides, and aptamers, e.g. nucleic acid or peptide aptamers. Methods to prepare such ligands are well-known in the art. For example, identification and production of suitable antibodies or aptamers is also offered by commercial suppliers. The person skilled in the art is familiar with methods to develop derivatives of such ligands with higher affinity or specificity. For example, random mutations can be introduced into the nucleic acids, peptides or polypeptides. These derivatives can then be tested for binding according to screening procedures known in the art, e.g. phage display. Antibodies as referred to herein include both polyclonal and monoclonal antibodies, as well as fragments thereof, such as Fv, Fab and F(ab)2 fragments that are capable of binding antigen or hapten. The present invention also includes single chain antibodies and humanized hybrid antibodies wherein amino acid sequences of a non- human donor antibody exhibiting a desired antigen-specificity are combined with sequences of a human acceptor antibody. The donor sequences will usually include at least the antigen-binding amino acid residues of the donor but may comprise other structurally and/or functionally relevant amino acid residues of the donor antibody as well. Such hybrids can be prepared by several methods well known in the art. Preferably, the ligand or agent binds specifically to the peptide or polypeptide. Specific binding according to the present invention means that the ligand or agent should not bind substantially to ("cross- react" with) another peptide, polypeptide or substance present in the sample to be analyzed. Preferably, the specifically bound peptide or polypeptide should be bound with at least 3 times higher, more preferably at least 10 times higher and even more preferably at least 50 times higher affinity than any other relevant peptide or polypeptide. Nonspecific binding may be tolerable, if it can still be distinguished and measured unequivocally, e.g. according to its size on a Western Blot, or by its relatively higher abundance in the sample. Binding of the ligand can be measured by any method known in the art. Preferably, said method is semi-quantitative or quantitative. Suitable methods are described in the following. First, binding of a ligand may be measured directly, e.g. by NMR or surface plasmon resonance.

Second, if the ligand also serves as a substrate of an enzymatic activity of the peptide or polypeptide of interest, an enzymatic reaction product may be measured (e.g. the amount of a protease can be measured by measuring the amount of cleaved substrate, e.g. on a Western Blot). Alternatively, the ligand may exhibit enzymatic properties itself and the "ligand/peptide or polypeptide" complex or the ligand which was bound by the peptide or polypeptide, respectively, may be contacted with a suitable substrate allowing detection by the generation of an intensity signal. For measurement of enzymatic reaction products, preferably the amount of substrate is saturating. The substrate may also be labelled with a detectable label prior to the reaction. Preferably, the sample is contacted with the substrate for an adequate period of time. An adequate period of time refers to the time necessary for a detectable, preferably measurable, amount of product to be produced. Instead of measuring the amount of product, the time necessary for appearance of a given (e.g. detectable) amount of product can be measured.

Third, the ligand may be coupled covalently or non-covalently to a label allowing detection and measurement of the ligand. Labelling may be done by direct or indirect methods. Direct labelling involves coupling of the label directly (covalently or non-covalently) to the ligand. Indirect labelling involves binding (covalently or non-covalently) of a secondary ligand to the first ligand. The secondary ligand should specifically bind to the first ligand. Said secondary ligand may be coupled with a suitable label and/or be the target (receptor) of tertiary ligand binding to the secondary ligand. The use of secondary, tertiary or even higher order ligands is often used to increase the signal. Suitable secondary and higher order ligands may include antibodies, secondary antibodies, and the well-known streptavidin-biotin system (Vector Laboratories, Inc.). The ligand or substrate may also be "tagged" with one or more tags as known in the art. Such tags may then be targets for higher order ligands. Suitable tags include biotin, digoxygenin, His-Tag, Glutathion-S- Transferase, FLAG, GFP, myc-tag, influenza A virus haemagglutinin (HA), maltose binding protein, and the like. In the case of a peptide or polypeptide, the tag is preferably at the N-terminus and/or C-terminus. Suitable labels are any labels detectable by an appropriate detection method. Typical labels include gold particles, latex beads, acridan ester, luminol, ruthenium, enzymatically active labels, radioactive labels, magnetic labels ("e.g. magnetic beads", including paramagnetic and superparamagnetic labels), and fluorescent labels. Enzymatically active labels include e.g. horseradish peroxidase, alkaline phosphatase, beta-Galactosidase, Luciferase, and derivatives thereof. Suitable substrates for detection include di-amino-benzidine (DAB), 3,3'-5,5'-tetramethylbenzidine, NBT- BCIP (4-nitro blue tetrazolium chloride and 5-bromo-4-chloro-3-indolyl -phosphate, available as ready-made stock solution from Roche Diagnostics), CDP-Star™ (Amersham Biosciences), ECF™ (Amersham Biosciences). A suitable enzyme-substrate combination may result in a coloured reaction product, fluorescence or chemoluminescence, which can be measured according to methods known in the art (e.g. using a light-sensitive film or a suitable camera system). As for measuring the enzymatic reaction, the criteria given above apply analogously. Typical fluorescent labels include fluorescent proteins (such as GFP and its derivatives), Cy3, Cy5, Texas Red, Fluorescein, and the Alexa dyes (e.g. Alexa 568). Further fluorescent labels are available e.g. from Molecular Probes (Oregon). Also the use of quantum dots as fluorescent labels is contemplated. Typical radioactive labels include 35S, 1251, 32P, 33P and the like. A radioactive label can be detected by any method known and appropriate, e.g. a light-sensitive film or a phosphor imager. Suitable measurement methods according the present invention also include precipitation (particularly immunoprecipitation), electrochemiluminescence (electro-generated chemiluminescence), RIA (radioimmunoassay), ELISA (enzyme-linked immunosorbent assay), sandwich enzyme immune tests, electrochemiluminescence sandwich immunoassays (ECLIA), dissociation-enhanced lanthanide fluoro immuno assay (DELFIA), scintillation proximity assay (SPA), turbidimetry, nephelometry, latex- enhanced turbidimetry or nephelometry, or solid phase immune tests. Further methods known in the art (such as gel electrophoresis, 2D gel electrophoresis, SDS polyacrylamid gel electrophoresis (SDS-PAGE), Wester Blotting, and mass spectrometry), can be used alone or in combination with labelling or other detection methods as described above.

The amount of a peptide or polypeptide may be, also preferably, determined as follows: (a) contacting a solid support comprising a ligand for the peptide or polypeptide as specified above with a sample comprising the peptide or polypeptide and (b) measuring the amount peptide or polypeptide which is bound to the support. The ligand, preferably chosen from the group consisting of nucleic acids, peptides, polypeptides, antibodies and aptamers, is preferably present on a solid support in immobilized form. Materials for manufacturing solid supports are well known in the art and include, inter alia, commercially available column materials, polystyrene beads, latex beads, magnetic beads, colloid metal particles, glass and/or silicon chips and surfaces, nitrocellulose strips, membranes, sheets, duracytes, wells and walls of reaction trays, plastic tubes etc. The ligand or agent may be bound to many different carriers. Examples of well-known carriers include glass, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polycarbonate, dextran, nylon, amyloses, natural and modified celluloses, polyacrylamides, agaroses, and magnetite. The nature of the carrier can be either soluble or insoluble for the purposes of the invention. Suitable methods for fixing/immobilizing said ligand are well known and include, but are not limited to ionic, hydrophobic, covalent interactions and the like. It is also contemplated to use "suspension arrays" as arrays according to the present invention (Nolan 2002, Trends Biotechnol. 20(1):9-12). In such suspension arrays, the carrier, e.g. a microbead or microsphere, is present in suspension. The array consists of different microbeads or microspheres, possibly labelled, carrying different ligands. Methods of producing such arrays, for example based on solid-phase chemistry and photo-labile protective groups, are generally known (US 5,744,305).

Preferably, the amounts of a cardiac troponin and a natriuretic peptide and, as the case may be, the amounts of other peptides measured in the context of the present invention are determined in a blood sample, e.g., a serum or plasma sample, obtained from a subject as defined in the present invention. Preferably, such a determination is done by ELISA. The amounts of troponin T and NT-proBNP can be determined by the COBAS assay, Roche Diagnostics Mannheim, Germany. The term "amount" as used herein encompasses the absolute amount (e.g., of a natriuretic peptide or a cardiac troponin), the relative amount or concentration (e.g., of a natriuretic peptide or a cardiac troponin) as well as any value or parameter which correlates thereto. Such values or parameters comprise intensity signal values from all specific physical or chemical properties obtained from the said peptides by direct measurements, e.g., intensity values in mass spectra or NMR spectra. Moreover, encompassed are all values or parameters which are obtained by indirect measurements specified elsewhere in this description, e.g., expression amounts determined from biological read out systems in response to the peptides or intensity signals obtained from specifically bound ligands. It is to be understood that values con-elating to the aforementioned amounts or parameters can also be obtained by all standard mathematical operations.

The term "comparing" as used herein encompasses comparing the amount of the peptide, polypeptide, protein comprised by the sample to be analyzed with an amount of a reference source specified elsewhere in this description. It is to be understood that comparing as used herein refers to a comparison of corresponding parameters or values, e.g., an absolute amount is compared to an absolute reference amount while a concentration is compared to a reference concentration or an intensity signal obtained from a test sample is compared to the same type of intensity signal of a reference sample. The comparison referred to in step (b) of the method of the present invention may be carried out manually or computer assisted. For a computer assisted comparison, the value of the determined amount may be compared to values corresponding to references which are stored in a database by a computer program. The computer program may further evaluate the result of the comparison, i.e. automatically provide the desired assessment in a suitable output format. Based on the comparison of the amount(s) determined in step a) to reference amount(s), it is possible to diagnose ischemia, reversible cardiac dysfunction and/or non reversible cardiac injury in said subject. It is to be understood that amounts of a natriuretic peptide or a cardiac troponin as determined in step (a) of the methods of the presents invention are compared in step (b) to reference amounts for a natriuretic peptide or a cardiac troponin as specified elsewhere in this application.

In general, for determining the respective amounts/amounts or amount ratios allowing to establish the desired diagnosis in accordance with the respective embodiment of the present invention, ("threshold", "reference amount"), the amount/amount(s) or amount ratios of the respective peptide or peptides are determined in appropriate patient groups. The term "reference amount" with respect to a cardiac troponin refers, preferably, to an amount of the cardiac troponin representing the upper level of normal found in a patient who is susceptible to PCI or bypass of at least one large coronary artery. With respect to a natriuretic peptide the term "reference amount", preferably, refers to the upper limit of normal in a patient who is not susceptible to PCI or bypass of at least one large coronary artery. The upper limit of normal is, preferably, defined by the 50th percentile, 55th percentile, 60th percentile, 65th percentile, 70th percentile, 75th percentile, 80th percentile, 85th percentile, 90th percentile, 90th percentile or 99th percentile.

The term "reference amount", preferably, refers to the amount of a cardiac troponin or a natriuretic peptide that allows the differentiation between a patient who is and a patient who is not susceptible to PCI or bypass of at least one large coronary artery. Thus, the reference amount, preferably, refers to the amount of a natriuretic peptide or a cardiac troponin that allows the differentiation between a patient who is and who is not susceptible to PCI or bypass of at least one large coronary artery.

According to the diagnosis to be established, the patient group may, for example, comprise only healthy individuals, or may comprise healthy individuals and individuals suffering from the pathophysiological state which is to be determined, or may comprise only individuals suffering from the pathophysiological state which is to be determined, or may comprise individuals suffering from the various pathophysiological states to be distinguished, by the respective marker(s) using validated analytical methods. In the context of monitoring the course of a disease, determining the susceptibility of a patient to a treatment or predicting the success of a treatment the groups are formed, preferably, by patients whose disease worsens and by patients whose disease improves over the course of observation. The results which are obtained are collected and analyzed by statistical methods known to the person skilled in the art. The obtained threshold values are then established in accordance with the desired probability of suffering from the disease and linked to the particular threshold value. For example, it may be useful to choose the median value, the 60^th, 70^th, 80^th, 90^th, 95^th or even the 99^th percentile of the healthy and/or non-healthy patient collective, in order to establish the threshold value(s), reference value(s) or amount ratios.

Consequently, threshold amounts for a cardiac troponin or a natriuretic peptide are, preferably, derived by determining the amount of the cardiac troponin or the natriuretic peptide in individuals who benefited from PCI or bypass of at least one large coronary artery.

A reference value of a diagnostic marker can be established, and the amount of the marker in a patient sample can simply be compared to the reference value. The sensitivity and specificity of a diagnostic and/or prognostic test depends on more than just the analytical "quality" of the test-they also depend on the definition of what constitutes an abnormal result. In practice, Receiver Operating Characteristic curves, or "ROC" curves, are typically calculated by plotting the value of a variable versus its relative frequency in "normal" and "disease" populations. For any particular marker of the invention, a distribution of marker amounts for subjects with and without a disease will likely overlap. Under such conditions, a test does not absolutely distinguish normal from disease with 100% accuracy, and the area of overlap indicates where the test cannot distinguish normal from disease. A threshold is selected, above which (or below which, depending on how a marker changes with the disease) the test is considered to be abnormal and below which the test is considered to be normal. The area under the ROC curve is a measure of the probability that the perceived measurement will allow correct identification of a condition. ROC curves can be used even when test results don't necessarily give an accurate number. As long as one can rank results, one can create an ROC curve. For example, results of a test on "disease" samples might be ranked according to degree (say Mow, 2=normal, and 3=high). This ranking can be correlated to results in the "normal" population, and a ROC curve created. These methods are well known in the art. See, e.g., Hanley et al, Radiology 143: 29-36 (1982). In certain embodiments, markers and/or marker panels are selected to exhibit at least about 70%) sensitivity, more preferably at least about 80% sensitivity, even more preferably at least about 85% sensitivity, still more preferably at least about 90% sensitivity, and most preferably at least about 95% sensitivity, combined with at least about 70% specificity, more preferably at least about 80%o specificity, even more preferably at least about 85% specificity, still more preferably at least about 90% specificity, and most preferably at least about 95% specificity. In particularly preferred embodiments, both the sensitivity and specificity are at least about 75%, more preferably at least about 80%>, even more preferably at least about 85%, still more preferably at least about 90%, and most preferably at least about 95%. The term "about" in this context refers to +/- 5% of a given measurement. In other embodiments, a positive likelihood ratio, negative likelihood ratio, odds ratio, or hazard ratio is used as a measure of a test's ability to predict risk or diagnose a disease. In the case of a positive likelihood ratio, a value of 1 indicates that a positive result is equally likely among subjects in both the "diseased" and "control" groups; a value greater than 1 indicates that a positive result is more likely in the diseased group; and a value less than 1 indicates that a positive result is more likely in the control group. In the case of a negative likelihood ratio, a value of 1 indicates that a negative result is equally likely among subjects in both the "diseased" and "control" groups; a value greater than 1 indicates that a negative result is more likely in the test group; and a value less than 1 indicates that a negative result is more likely in the control group. In certain preferred embodiments, markers and/or marker panels are preferably selected to exhibit a positive or negative likelihood ratio of at least about 1.5 or more or about 0.67 or less, more preferably at least about 2 or more or about 0.5 or less, still more preferably at least about 5 or more or about 0.2 or less, even more preferably at least about 10 or more or about 0.1 or less, and most preferably at least about 20 or more or about 0.05 or less. The term "about" in this context refers to +/- 5% of a given measurement.

In the case of an odds ratio, a value of 1 indicates that a positive result is equally likely among subjects in both the "diseased" and "control" groups; a value greater than 1 indicates that a positive result is more likely in the diseased group; and a value less than 1 indicates that a positive result is more likely in the control group. In certain preferred embodiments, markers and/or marker panels are preferably selected to exhibit an odds ratio of at least about 2 or more or about 0.5 or less, more preferably at least about 3 or more or about 0.33 or less, still more preferably at least about 4 or more or about 0.25 or less, even more preferably at least about 5 or more or about 0.2 or less, and most preferably at least about 10 or more or about 0.1 or less. The term "about" in this context refers to +/- 5% of a given measurement. In the case of a hazard ratio, a value of 1 indicates that the relative risk of an endpoint (e.g., death) is equal in both the "diseased" and "control" groups; a value greater than 1 indicates that the risk is greater in the diseased group; and a value less than 1 indicates that the risk is greater in the control group. In certain preferred embodiments, markers and/or marker panels are preferably selected to exhibit a hazard ratio of at least about 1.1 or more or about 0.91 or less, more preferably at least about 1.25 or more or about 0.8 or less, still more preferably at least about 1.5 or more or about 0.67 or less, even more preferably at least about 2 or more or about 0.5 or less, and most preferably at least about 2.5 or more or about 0.4 or less. The term "about" in this context refers to +/- 5% of a given measurement. The reference amount for troponin T is, preferably about 4.0 pg/ml, about 4.5 pg/ml, about 5.0 pg/ml, about 5.5 pg/ml, about 6.0 pg/ml, about 6.5 pg/ml, about 7.0 pg/ml, about 7.5 pg/ml, about 8.0 pg/ml, about 8.5 pg/ml, about 9.0 pg/ml, about 9.5 pg/ml or about 10.0 pg/ml. A measured amount of troponin T lower than the reference amount is, preferably, indicative for a patient susceptible to PCI or bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement.

In another preferred embodiment the reference amount for troponin T corresponds to the 25^th or 50^th percentile of a collective of patients in whom PCI was successful. More preferably said reference amount is about 5.0 pg/ml or about 8.3 pg/ml, most preferably about 5.0 pg/ml. A measured amount of troponin T lower than the reference amount is, preferably, indicative for a patient susceptible to PCI or bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement.

The reference amount for NT-pro BNP is, preferably, about 180 pg/ml, about 210 pg/ml, about 240 pg/ml, about 270 pg/ml, about 300 pg/ml, about 330 pg/ml, about 360 pg/ml, about 390 pg/ml, about 420 pg/ml, about 450 pg/ml, about 480 pg/ml or about 510 pg/ml. A measured amount of NT-proBNP higher than the reference amount is, preferably, indicative for a patient susceptible to PCI or bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement.

In another preferred embodiment the reference amount for NT-proBNP corresponds to the 25^th or 50^th percentile of a collective of patients in whom PCI or implantation of the bypass of at least one large coronary artery was successful. More preferably, the reference amount is about 211 pg/ml or about 431 pg/ml, most preferably about 431 pg/ml. A measured amount of NT-proBNP higher than the reference amount is, preferably, indicative for a patient susceptible to PCI or bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement.

A patient who is susceptible to PCI or bypass of at least one large coronary artery may additionally receive medical treatment as susceptibility to PCI or bypass of at least one large coronary artery does not prevent the patient from benefitting from medical treatment. A reference amount of troponin T higher than about 8.0 pg/ml, higher than about 9.0 pg/ml, higher than about 10.0 pg/ml, higher than about 1 1.0 pg/ml, higher than about 12. pg/ml, higher than about 13.0 pg/ml, higher than about 14.0 pg/ml, higher than about 15.0 pg/ml, higher than about 16.0 pg/ml, higher than about 17.0 pg/ml, or higher than about 18.0 pg/ml is, preferably, indicative of a patient not susceptible to PCI or the bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement. A measured amount of troponin T higher than the reference amount is, preferably, indicative for a patient not susceptible to PCI or bypass of at least one large coronary artery.

In another preferred embodiment the reference amount for troponin T corresponds to the 50^th or 75^th percentile of a collective of patients in whom PCI or bypass of at least one large coronary artery was not successful. More, preferably, the reference amount is about 10.6 pg/ml or about 15.2 pg/ml, most preferably about 15.2 pg/ml. The term "about" in this context refers to +/- 5% of a given measurement. A measured amount of troponin T higher than the reference amount is, preferably, indicative for a patient not susceptible to PCI or bypass of at least one large coronary artery. A reference amount of NT-proBNP lower than about 400 pg/ml, about 350 pg/ml, about 300 pg/ml, about 250 pg/ml, about 200 pg/ml, about 150 pg/ml, about 100 pg/ml or lower than about 50 pg/ml is, preferably, indicative for a patient not susceptible to PCI or bypass of at least one large coronary artery. The term "about" in this context refers to +/- 5% of a given measurement. A measured amount of NT-proBNP lower than the reference amount is, preferably, indicative for a patient not susceptible to PCI or bypass of at least one large coronary artery.

In another preferred embodiment the reference amount for NT-proBNP corresponds to the 25^th or 50^th percentile of a collective of patients in whom PCI or the implantation of the bypass of at least one large coronary artery was not successful. More preferably, the reference amount is about 126 pg/ml or about 96 pg/ml, most preferably 96 pg/ml. The term "about" in this context refers to +/- 5% of a given measurement. A measured amount of NT-proBNP lower than the reference amount is, preferably, indicative for a patient not susceptible to PCI or bypass of at least one large coronary artery. In an especially preferred embodiment of the present invention the ratio of the natriuretic peptide or the variant thereof to the amount of the cardiac troponin or the variant thereof is used as a reference amount. Because both markers show opposite trends in patients who are susceptible to PCI or bypass of at least one large coronary artery and in patients who are not, the ratio of said markers improves the discrimination between both groups. It is to be understood that the reciprocal of the aforementioned ratio has an identical diagnostic value.

Preferably, a ratio of the natriuretic peptide or a variant thereof to the cardiac troponin or a variant thereof of more than about 20, more than about 25 or more than about 30 indicates that the patient is susceptible to PCI or bypass of at least one large coronary artery. More preferably, the ratio is higher than about 35, higher than about 40 or higher than about 45. Most preferably, the ratio is higher than about 41.

Preferably, a ratio of the natriuretic peptide or a variant thereof to the cardiac troponin or a variant thereof of less than about 35, less than about 40 or less than about 45 indicates that the patient is not susceptible to PCI or bypass of at least one large coronary artery. More preferably, the ratio is lower than about 20, lower than about 25 or lower than about 30. Most preferably, the ratio is lower than about 25. In a patient suffering from coronary artery disease who is diagnosed as not being not susceptible to PCI according to the method of the present invention, a thallium-scan is, preferably, performed in order to assess whether the stenosis affects large or small vessels. If the thallium scan indicates that the stenosis is located in one or more large vessels, PCI or the implantation of the bypass of at least one large coronary artery me be performed even though the method of the present invention does not predict a positive outcome. In a thallium-scan the patient receives a radioactive marker, such as thallium-201 or technetium-99, intravenously. The radioactive marker is distributed by the blood stream and its distribution, thus, indicates the level of blood supply in the body part in question. A thallium-scan is, preferably, combined with physical exercise (e.g. walking on a treadmill) or the administration of a pharmaceutical that simulates physical exercise (e.g. dipyridamole, adenosine or dobutamine). By monitoring the distribution of the radioactive label in the myocardium, areas with insufficient blood supply can be detected.

However, a patient who is (based on the method of the present invention and a thallium scan) not susceptible to PCI or bypass of at least one large coronary artery nevertheless requires treatment. Such a patient receives, preferably, medical treatment or bypass of small coronary vessels.

Advantageously, the present invention allows the differentiation of patients who are susceptible to a treatment selected from PCI and bypass of at least one large coronary artery and those patients who are not. PCI and bypass of at least one large coronary artery are associated with the risk of undesired side-effects such as myocardial infarction caused by the release of plaque material. Therefore, PCI and bypass of at least one large coronary artery should be restricted to those patients, where the potential benefits outweigh the risk of side-effects. For the patients the avoidance of unnecessary PCI or bypass of at least one large coronary artery means the reduction of risks and stresses associated with these therapies. Thus, the patient receives the optimal therapy for his/her condition. This may be PCI or bypass of at least one large coronary artery, optionally combined with medical therapy. Or it may be medical therapy and/or bypass of small coronary vessels if the method of the present invention indicates that this particular patient is unlikely to benefit from PCI or bypass of at least one large coronary artery. For the health system as a whole the targeting of PCI and bypass of at least one large coronary artery to those patients that benefit from it allows a more efficient use of resources. It is also provided for a method for deciding whether a patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels comprising the steps of a) Determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) Comparing the measured amount of the respective biomarker to a reference amount; whereby the results obtained in step b) indicate whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels. Preferably, the method of the present invention comprises at least one of the following steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the respective biomarker to a reference amount; and c) deciding whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

Accordingly the present invention relates to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

c) deciding whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

Additionally, the present invention relates to a method for determining whether a patient requires additional diagnostic procedures for deciding whether he/she is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

c) deciding whether additional diagnostic procedures need to be performed in order to decide whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

The patient as referred to in the above methods, in a preferred embodiment, suffers from coronary artery disease, even more preferably from stable coronary artery disease.

The present invention also provides a method for deciding if a patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels, comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the respective biomarker to a reference amount; whereby the, results obtained in step b) indicate whether the patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

Preferably, the method of the present invention comprises at least one of the following steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the respective biomarker to a reference amount; and c) deciding whether the patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

Accordingly the present invention relates to a method for deciding if a patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels, comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the respective biomarker to a reference amount; and

c) deciding whether the patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or to a treatment selected from medical treatment and bypass of small coronary vessels.

The patient, in a preferred embodiment, suffers from coronary artery disease, even more preferably from stable coronary artery disease. If the measured amount of the cardiac troponin or the variant thereof is lower than the reference amount and the measured amount of the natriuretic peptide or the variant thereof is higher than the reference amount or - in the case of a ratio of the amount of the natriuretic peptide and the amount of the cardiac troponin - the ratio is higher then the reference amount, PCI or bypass of at least one large coronary artery is likely to be successful. Thus, additional diagnostic procedures to determine whether the patient will benefit from PCI or bypass of at least one large coronary artery are less important and may be omitted. However, if the measured amount of the cardiac troponin or the variant thereof is higher than the reference amount and the measured amount of the natriuretic peptide or the variant thereof is lower than the reference amount or - in the case of a ratio of the amount of the natriuretic peptide and the amount of the cardiac troponin - the ratio is lower than the reference amount, there is a high probability that the patient will not benefit from PCI or bypass of at least one large coronary artery. Thus, additional diagnostic procedures, preferably a thallium scan, are required to decide finally, whether the patient is likely to benefit from a treatment selected from PCI and bypass of at least one large coronary artery or not.

Moreover, the present invention relates to a method for predicting the success of a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery based on the determination of the amount of a cardiac troponin or a variant thereof and/or the amount of a natriuretic peptide or a variant thereof in sample of a patient and the comparison of the measured amount of the respective biomarker to a reference amount.

Preferably, the method comprises at least one of the following steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the respective biomarker to a reference amount; and c) predicting whether a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery will be successful in the patient.

Accordingly, the present invention relates to a method for predicting the success of a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery in a patient comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the respective biomarker to a reference amount; whereby it is predicted whether a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery in the patient will be successful.

The patient preferably suffers from coronary artery disease, even more preferably from stable coronary artery disease.

As can be seen from example 3 the amounts of a cardiac troponin and a natriuretic peptide before PCI or bypass of at least one large coronary artery indicate whether PCI or bypass of at least one large coronary artery will be successful. Successful PCI or bypass of at least one large coronary artery, preferably, leads to increased blood flow through the treated coronary artery, increased oxygen supply of at least a part of the myocardium, decrease of the frequency and severity of bouts of angina pectoris, decrease of the extent of myocardial necrosis and a decreased risk of acute cardiovascular events.

A preferred biomarker for the success of PCI or bypass of at least one large coronary artery is a cardiac troponin or a variant thereof. Since cardiac troponins are released from the myocardium as a result of ischemia, the comparison of the amounts of said markers in a sample taken after PCI or bypass of at least one large coronary artery as compared to a sample taken before PCI or bypass of at least one large coronary artery may serve as an indicator of successful PCI or bypass of at least one large coronary artery. Consequently, the present invention also relates to a method for deciding whether PCI or bypass of at least one large coronary artery was successful in a patient based on the determination of a cardiac troponin or a variant thereof and/or the amount of a natriuretic peptide or a variant thereof in a sample of a patient.

Preferably, the method of the present invention comprises at least one of the following steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a first sample of the patient; b) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in at least one further sample of the patient; c) comparing the measured amounts of the respective biomarker in the first and the at least one further sample; and d) deciding whether or not PCI or bypass of at least one large coronary artery was successful. Accordingly the present invention relates to a method for determining whether percutaneous coronary intervention (PCI) or bypass of at least one large coronary artery in a patient was successful comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a first sample of the patient; b) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in at least one further sample of the patient

c) comparing the measured amounts of the respective biomarker measured in the first and the at least one further sample; and

d) deciding whether PCI or bypass of at least one large coronary artery in the patient was successful.

The first sample is, preferably, taken before PCI or implantation of a bypass of at least one large coronary artery is performed in the patient. More preferably, the first sample is taken not more than about 6 days, not more than about 3 days or not more than about 1 day before PCI or implantation of a bypass of at least one large coronary artery. The at least one further sample is, preferably, taken at least about 1 month, at least about 2 months or at least about 3 months after PCI or bypass of at least one large coronary artery is performed. The term "about" in this context refers to +/- 5% of a given measurement. Because the amounts of cardiac troponins or their variants react faster to reduced ischemia of the myocardium (see example 2), the use of a cardiac troponin or a variant thereof is preferred over the use of a natriuretic peptide as a single marker.

The above described method can also be used for monitoring the success of PCI or bypass of at least one large coronary artery, wherein the mounts a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof are determined at least twice after PCI bypass of at least one large coronary artery has been performed.

In general, it can be said that within the context of the present invention, it is generally preferred, within the group of treatments selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery, to carry out PCI. This is due to the risk of complications which may arise from the surgical intervention connected with bypass grafting. PCI, however, is minimum invasive surgery and less prone to complications. In some cases which are known to the person skilled in the art, it may, however, be preferred to graft a bypass.

In respect to the choice between medical treatment and bypass of small coronary vessels, it will in general be decided on a case-to-case basis which treatment is preferred. The criteria are known to the person skilled in the art. What has been laid out beforehand in respect to the risks associated with bypass grafting also applies for a bypass of small coronary vessels. However, it has to be taken into consideration that in many cases medical treatment is not sufficient to effectively treat the coronary disease, preferably the coronary artery disease, of the respective individual. In these cases (i.e. in patients showing advanced coronary disease which cannot or can only hardly be treated by administration of medicaments), bypass grafting may be preferred vis-a-vis medical treatment.

Moreover, the present invention relates to a device for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising a) an analyzing unit for determining the amounts of a cardiac troponin or a variant thereof and/or a natriuretic peptide or a variant thereof in a sample of a patient; and b) an evaluation unit for comparing the measured amount of the cardiac troponin or the variant thereof and/or the natriuretic peptide or the variant thereof with reference amounts.

The term "device" as used herein relates to a system of means comprising at least the aforementioned means operatively linked to each other as to practise the method of the present invention. Preferred means for determining the amounts of the markers of the present invention, and means for carrying out the comparison are disclosed above in connection with the method of the invention. How to link the means in an operating manner will depend on the type of means included into the device. For example, where an analysis unit for automatically determining the amount of the gene products of the present invention is applied, the data obtained by said automatically operating analysis unit can be processed by, e.g., a computer as evaluation unit in order to obtain the desired results. Preferably, the means are comprised by a single device in such a case.

Said device, preferably, includes an analyzing unit for the measurement of the amount of a natriuretic peptide and/or a cardiac troponin in an applied sample and an evaluation unit for processing the resulting data. Preferably, the evaluation unit comprises a database with the stored reference amounts and a computer program code which when tangibly embedded on a computer carries out the comparison of the determined amounts and the reference amounts stored in the database. More preferably, the evaluation unit comprises a further computer program code which allocates the result of the comparison to a risk prediction. In such a case, it is, also preferably, envisaged that the evaluation unit comprises a further database wherein the reference amounts are allocated to the risks.

Alternatively, where means such as test stripes are used for determining the amount of the natriuretic peptide and/or the cardiac troponin, the evaluation unit may comprise control stripes or tables allocating the determined amount to a reference amount. The test stripes are, preferably, coupled to a ligand which specifically binds to the natriuretic peptide or the cardiac troponin. The strip or device, preferably, comprises means for detection of the binding of said natriuretic peptide or cardiac troponin to the said ligand. Preferred means for detection are disclosed in connection with embodiments relating to the method of the invention above. In such a case, the analysis unit and the evaluation unit are operatively linked in that the user of the system brings together the result of the determination of the amount and the diagnostic or prognostic value thereof due to the instructions and interpretations given in a manual. The analysis unit and the evaluation unit may appear as separate devices in such an embodiment and are, preferably, packaged together as a kit. The person skilled in the art will realize how to link the means without further ado. Preferred devices are those which can be applied without the particular knowledge of a specialized clinician, e.g., test stripes or electronic devices which merely require loading with a sample. The results may be given as output of raw data which need interpretation by the clinician. Preferably, the output of the device is, however, processed, i.e. evaluated, raw data the interpretation of which does not require a clinician. Further preferred devices comprise the analyzing units/devices (e.g., biosensors, arrays, solid supports coupled to ligands specifically recognizing the gene product, Plasmon surface resonance devices, NMR spectrometers, mass-spectrometers etc.) or evaluation units/devices referred to above in accordance with the method of the invention.

In an especially preferred embodiment of the present invention the analyzing unit of the device allows the calculation of the ratio of the amount of a natriuretic peptide or a variant thereof to the amount of a cardiac troponin or a variant thereof.

Moreover, the present invention relates to a kit for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising a) an analyzing agent for determining the amounts of a cardiac troponin or a variant thereof and/or a natriuretic peptide or a variant thereof in a sample of a patient; and b) an evaluation unit for comparing the measured amount of the cardiac troponin or the variant thereof and/or the natriuretic peptide or the variant thereof with reference amounts.

The term "kit" as used herein refers to a collection of the aforementioned components of which may or may not be packaged together. The components of the kit may be comprised by separate vials (i.e. as a kit of separate parts) or provided in a single vial. Moreover, it is to be understood that the kit of the present invention is to be used for practising the methods referred to herein above. It is, preferably, envisaged that all components are provided in a ready-to-use manner for practising the methods referred to above. Further, the kit preferably contains instructions for carrying out the said methods. The instructions can be provided by a user's manual in paper- or electronic form. For example, the manual may comprise instructions for interpreting the results obtained when carrying out the aforementioned methods using the kit of the present invention. The kit shall comprise an analyzing agent. This agent is capable of specifically recognizing a natriuretic peptide and/or a cardiac troponin in a sample of the subject. Moreover, the said agent shall upon binding to the natriuretic peptide and/or a cardiac troponin, preferably, be capable of generating a detectable signal, the intensity of which correlates to the amount of the natriuretic peptide or the cardiac troponin present in the sample. Dependent on the type of signal which is generated, methods for detection of the signal can be applied which are well known in the art. Analyzing agents which are preferably used for the kit of the present invention include antibodies or aptamers. The analyzing agent may be present on a test stripe as described elsewhere herein. The amounts of the natriuretic peptide and/or the cardiac troponin thus detected can then be further evaluated in the evaluation unit. Preferred evaluation units to be used for the kit of the present invention include those referred to elsewhere herein.

The present invention also relates to the use of a kit or device for determining the amount of a natriuretic peptide or a variant thereof and/or a cardiac troponin or a variant thereof in a sample of a subject, comprising means for determining the amount of the natriuretic peptide or the variant thereof and/or the cardiac troponin or the variant thereof and/or means for comparing the amount of the natriuretic peptide or the variant thereof and/or the cardiac troponin or the variant thereof to at least one reference amount for: selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether a patient who suffers from coronary artery disease is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether additional diagnostic procedures are required in order to determine whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery. The present invention also relates to the use of: an antibody against a cardiac troponin or a variant thereof and/or an antibody against a natriuretic peptide or a variant thereof and/or of means for deteiTnining the amount of a natriuretic peptide or a variant thereof and/or a cardiac troponin or a variant thereof and/or of means for comparing the amount of the cardiac troponin or the variant thereof and/or the natriuretic peptide or the variant thereof to at least one reference amount for the manufacture of a diagnostic composition for: selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether a patient who suffers from coronary artery disease is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether additional diagnostic procedures are required in order to determine whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery.

The present invention also relates to the use of: a natriuretic peptide or a variant thereof and/or a cardiac troponin or a variant thereof and/or of means for determining the amount of a natriuretic peptide or a variant thereof and/or a cardiac troponin or a variant thereof, and/or of means for comparing the amount of the natriuretic peptide or the variant thereof and/or of the cardiac troponin or the variant thereof to at least one reference amount for: selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether a patient who suffers from coronary artery disease is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or deciding whether additional diagnostic procedures are required in order to determine whether the patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery.

Moreover, the present invention relates to a method for predicting the risk of a patient to suffer from acute coronary syndromes based on the determination of the amount of a natriuretic peptide and/or a cardiac troponin in a sample of the patient and the comparison of the determined amount or amounts with a reference amount or reference amounts.

It is also provided for a method for diagnosing a myocardial infarction in a patient comprising the steps of a) determining the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the cardiac troponin or the variant thereof to a reference amount; whereby the results obtained in step b) indicate whether the patient suffers from a myocardial infarction.

Moreover, it is provided for a method for excluding the presence of pulmonary embolism in a patient comprising the steps of a) determining the amount of D-dimer or a variant thereof in a sample of the patient; b) comparing the amount of D-dimer or the variant thereof determined in step a) to a reference amount; and

c) excluding the presence of pulmonary embolism in the patient if the determined amount of D-dimer or the variant thereof is lower than the reference amount.

Preferably, the method of the present invention comprises the steps of a) determining the amount of a cardiac troponin or a variant thereof in a sample of the patient; b) comparing the measured amount of the cardiac troponin or the variant thereof to a reference amount; and c) diagnosing whether the patient suffers from a myocardial infarction.

A further embodiment of the present invention relates to a method for diagnosing heart failure in a patient comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof in a sample of the patient;

b) comparing the measured amount of the natriuretic peptide or the variant thereof to a reference amount; whereby the results obtained in step b) indicate whether the patient suffers from heart failure.

Preferably, the method of the present invention comprises the steps of a) determining the amount of a natriuretic peptide or a variant thereof in a sample of the patient; b) comparing the measured amount of the natriuretic peptide or the variant thereof to a reference amount; and c) diagnosing whether the patient suffers from a heart failure.

The following examples are merely intended to illustrate the present invention. They shall not limit the scope of the claims in any way. Example 1: Analytical methods

Troponin T was measured with an immunoassay to be used with the Elecsys and COBAS analyzers from Roche Diagnostics, Mannheim, Germany. The test is capable of measuring troponin T-concentrations from 3 pg/ml to 10000 pg/ml. The assay is based on the sandwich principle and comprises two monoclonal troponin-T specific antibodies. The first of these is biotinylated and the second one is labeled with a Tris(2,2'- hipyridyl)ruthenium(TT)-complex. In a first incubation step both antibodies are incubated with the human serum sample. A sandwich complex comprising cardiac troponin T and the two different antibodies is formed. In a next incubation step streptavidin-coated beads are added to this complex. The beads bind to the sandwich complexes. The reaction mixture is then aspirated into a measuring cell where the beads are magnetically captured on the surface of an electrode. The application of a voltage then induces a chemiluminescent emission from the ruthenium complex which is measured by a photomultiplier. The amount of light is dependent on the amount of sandwich complexes on the electrode.

NT-proBNP was tested with a sandwich immuno-assay using a COBAS analyzer from HTACHI-ROCHE. The principle of the test was the same as described above for the troponin-T-immunoassay. The test is capable of measuring NT-proBNP concentrations from 5 pg/ml to 35000 pg/ml.

The GDF-15 assay contains antibodies obtained from R&D systems, Minneapolis, USA and the test is adopted to the assay described by Wollert et al in Clinical Chemistry 53, 2, 284 - 291 , 2007. The measuring range of the test is between 300 and 20000 pg/ml.

Example 2: Patients with stable angina undergoing STENT implantation

30 Patients (18 males, 12 females, mean age 62.7 years) with stable angina and normal kidney function (glomerular filtration rate of more than 60 ml per minute and 1.73 m² body surface or serum creatinine value lower than 1.3 mg/dl) underwent STENT implantation. Samples were taken before (baseline level) and 30 days after STENT implantation. At each time point troponin T, growth differentiation factor 15 (GDF-15) and NT-proBNP were determined. Test results measured after 30 days were compared to the test results before intervention. A decrease of troponin T and NT-pro BNP was assumed if the test result 30 days after STENT implantation was at least 20% below baseline level. For GDF-15 a 30 days after STENT implantation value at least 10% below baseline was defined as a decrease.

Table 1: Biomarkers in atients under oin STENT im lantation

Patients who met the criteria of decrease of the respective biomarker, tests showed decreases between 10% and 20% for GDF-15 when results after 30 days were compared to baseline (pre-treatment) results. NT-proBNP decreases in the patients described in Table 1 ranged from 26% to 72% and troponin T decreases ranged from 22% to 94% as compared to baseline values. Decreased troponin T amounts indicate a reduced necrosis in the patients in question. Because improved perfusion of the myocardium reduces necrosis almost immediately, a decrease of troponin T levels was found most frequently. The myocardium in previously stable patients requires several months to adapt to the improved perfusion by remodelling. This remodelling is reflected by decreasing NT-proBNP levels in previously stable patients. The longer time required for remodelling, thus, explains the lower number of patients with decreased NT-proBNP 30 days after PCI. Due to their quick response cardiac troponins are the most useful markers for monitoring the effect of PCI and STENT implantation. Troponin T was the marker that most frequently decreased after STENT implantation in clinically stable patients. The reduction in necrosis was in 3 cases associated with a significant improvement of cardiac function as assessed by NT-proBNP levels and confirmed by echocardiography. Results from echocardiography suggest improved functionality from viable myocardium and thereby improved cardiac function.

Example 3: NT-proBNP and troponin T as predictors of troponin T decrease following PCI In order to identify patients that are most likely to benefit from STENT implantation the amounts of troponin T, NT-proBNP and GDF-15 at baseline, i.e. before STENT implantation, were determined in the group of patients described in example 2 and compared to the outcome. STENT implantation was considered as successful if the amount of troponin T dropped by at least 20% as compared to the baseline level. Given the quick response to improved perfusion of the myocardium (see example 2) cardiac troponins, in particular troponin T, are the best biomarkers for monitoring the success of PCI 30 days after the procedure. Due to its slower response, NT-proBNP is less suitable for this purpose.

Table 2a: Biomarker levels at baseline in Patients with successful and

unsuccessful PCI

Table 2b: Ratio of NT-proBNP to ti oponin T at baseline in

Patients with successful and unsuccessfu PCI

NT-proBNP/troponin T

PCI successful 25^th Percentile 41

50^th Percentile 53

75^th Percentile 78

PCI not successful 25^th Percentile 1 1.9

50^th Percentile 12.2

75^th Percentile 24.8 As can be seen from Table 2a patients that benefitted from PCI (as indicated by a decrease of necrosis) were characterized by lower troponin T levels and higher NT-proBNP levels at baseline. The difference between the two groups of patients is even more striking if the ratio of NT-proBNP to troponin T is calculated. This ratio is in patients who are susceptible to PCI about three to four times higher than in patients who are not. Thus, cardiac troponins, especially troponin T, and natriuretic peptides, especially NT-proBNP, preferably a combination of a cardiac troponin and a natriuretic peptide, are useful predictors of the success of PCI and to select patients either for PCI or for medical treatment without PCI.

The study underlying the present invention revealed surprising findings. The opening of a major coronary vessel using STENT implantation was most effective - based on a decrease of Troponin T 30 days after the invention, if the subject with stable coronary heart disease had "high" levels of NT-pro BNP but surprisingly "low" levels of troponin T. Also surprisingly "low" levels of NT-pro BNP and "high" levels of troponin T were associated with unsuccessful PCI - as defined as a failure of troponin T to decrease 30 days after reopening of a major vessel.

GDF-15 has been shown to predict adverse cardiovascular events in acute coronary syndrome (Wollert V.C., Circulation 2007, 1 15, 962 - 971) and in heart failure (Kempf T. et al J Am Coll Cardiol 2007, 50: 1054 - 1060). Thus, it is surprising that the level of GDF-15 before PCI did not contribute to the prediction of successful or non successful PCI. In a total of 6 patients (3 with successful PCI and 3 without successful PCI) a thallium scan was performed (according to Udelson et al, Chapter 16 in Braunwalds Heart disease) which measures cardiac perfusion. Improvement of perfusion was noted in patients who had a "decrease" in Troponin T 30 days after STENT implantation, i.e. at least 20% decrease of Troponin T relative to baseline level, but not in those who had no "decrease" in Troponin T levels. Apparently, in individuals who do not benefit from PCI (i.e. who show no "decrease" of Troponin T) small vessel disease predominates large vessel disease and, thus, the reopening of a larger vessel is without benefit. As a consequence, patients with high Troponin T levels and low NT-proBNP levels should, in general, not undergo PCI because of suspected predominant small vessel disease. Alternatively, a thallium scan preferably with a CT Scan or MRI should be performed in order to assess whether perfusion defects match stenosis of larger vessels. Additionally or alternatively, a gadolinium scan (coupled with computed tomography and echocardiography) could be performed. Thus, the method of the current invention offers significant benefit to candidates for PCI in directing diagnostic approaches and improving benefit risk ratio.

Claims

A method for deciding whether a patient is susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient; and

b) comparing the measured amount of the respective biomarker to a reference amount, wherein an amount of the cardiac troponin or the variant thereof lower than the reference amount and/or an amount of the natriuretic peptide higher than the reference amount indicate that the patient is susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery.

The method of claim 1, wherein the patient suffers from a stable coronary artery disease.

The method of claim 1 or 2, wherein the natriuretic peptide is a BNP-type peptide.

The method of claim 3, wherein the BNP-type peptide is NT-proBNP.

The method of any of claims 1 to 4, wherein the cardiac troponin is troponin T.

The method according to any of claims 1 to 5, wherein the patient is treated by percutaneous coronary intervention.

Use of an antibody against a cardiac troponin or a variant thereof and an antibody against a natriuretic peptide or a variant thereof for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery.

8. Use of a cardiac troponin or a variant thereof and a natriuretic peptide or a variant thereof for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery.

9. A method for predicting the success of a treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery in a patient comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

c) whereby it is predicted whether the treatment selected from percutaneous coronary intervention and bypass of at least one large coronary artery will be successful in the patient.

10. A method for deciding if a patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or by a treatment selected from medical treatment and bypass of small coronary vessels, comprising the steps of a) determining the amount of a natriuretic peptide or a variant thereof and/or the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the respective biomarker to a reference amount; whereby the results of the comparison indicate whether the patient is to be treated by a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery or by a treatment selected from medical treatment and bypass of small coronary vessels.

11. A method for diagnosing a myocardial infarction in a patient comprising the steps of a) determining the amount of a cardiac troponin or a variant thereof in a sample of the patient;

b) comparing the measured amount of the cardiac troponin or the variant thereof to a reference amount;

c) diagnosing whether the patient suffers from a myocardial infarction based on the results obtained in step b).

12. A device for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising a) an analyzing unit for determining the amounts of a cardiac troponin or a vaiiant thereof and/or a natriuretic peptide or a variant thereof in a sample of a patient; and

b) an evaluation unit for comparing the measured amount of the cardiac troponin or the variant thereof and/or the natriuretic peptide or the variant thereof with reference amounts.

13. A kit for selecting a patient susceptible to a treatment selected from percutaneous coronary intervention (PCI) and bypass of at least one large coronary artery comprising a) an analyzing agent for determining the amounts of a cardiac troponin or a variant thereof and/or a natriuretic peptide or a variant thereof in a sample of a patient; and