WO2001097879A1

WO2001097879A1 - Apparatus and method for perfusing the kidney with venous blood

Info

Publication number: WO2001097879A1
Application number: PCT/US2000/017013
Authority: WO
Inventors: Howard R. Levin; David C. Lundmark
Original assignee: Chf Solutions, Inc.
Priority date: 2000-06-20
Filing date: 2000-06-20
Publication date: 2001-12-27
Also published as: AU2000260532A1

Abstract

This is an apparatus and method for perfusing a kidney with venous blood exported from a vein within the same body. A tubular member is placed between the export vein and the renal artery to form a lumen which fluidly connects the two vessels. A pump is interfaced with the tubular member in a configuration wherein blood may be controllably pumped from the export vein to the renal artery.

Description

APPARATUS AND METHOD FOR PERFUSING THE KIDNEY WITH VENOUS BLOOD

TECHNICAL FIELD The present invention relates to the field of fluid perfusion devices. More particularly, it relates to an apparatus and method for perfusing the mammalian kidney with venous blood.

BACKGROUND ART The classification of cessation of renal function into acute and chronic renal failure demarcates disease states that are distinct in etiology, pathogenesis, rate of loss of renal function, potential for recovery of renal function and therapeutic strategies applied in their management. Chronic renal failure is characterized by an inexorable loss of renal function, which can last for several years after the initial presentation of renal insufficiency, culminating in end-stage disease. The arrival of end-stage disease signifies irretrievable loss of renal function and necessitates replacement of renal function by dialysis or transplantation. The leading causes of chronic renal failure are assorted glomerulonephritides, diabetic nephropathy, chronic tubulointerstitial diseases and polycystic kidney diseases. See F. N. Ziyadeh, Textbook of Internal Medicine, Vol. 1, . E. Kelley, ed., J. B. Lippincott Co., Philadelphia (1989) at pages 883-889; M. Walser, Kid. Int., 37, 1195 (1990).

Management of patients with chronic renal failure utilizes strategies that retard the rate of loss of renal function, thereby delaying the onset of end-stage disease. Such therapeutic strategies include treatment of systemic hypertension, correction of perturbed calcium/phosphate homeostasis and restriction in dietary protein intake (W. E. Mitch, Ann. Rev. Med., 35, 249 (1984)). Some studies have indicated that dietary supplementation with alpha-keto acids in conjunction with restricted protein and phosphate intake may be efficacious in retarding the progression of established renal disease (W. E. Mitch et al . , N. Engl . J. Med., 311, 623 (1984)). The mechanism by which dietary supplementation with alpha-keto acids may act to alleviate progressive renal injury is unknown.

The syndrome of acute renal failure is characterized by a relatively rapid decline in renal function that leads to the accumulation of water, crystalloid solutes, and nitrogenous metabolites in the body. Pre-renal (upstream from the kidney in the circulatory system) causes can lead to renal failure by decreasing the effective perfusion of the kidney (hypoperfusion) . An absolute decrease in blood volume, the most common pre- renal disorder, may be caused by skin, gastrointestinal, and renal losses of water and electrolytes, hemorrhage, and sequestration of fluids in body cavities. In some conditions the kidneys respond as though the blood volume were decreased, when in fact the measured volume is normal or even increased. Such states include congestive heart failure (which may be precipitated by myocardial infarction, dysrhytmia, disease effecting the heart muscle, heart valve disorder, prolonged hypertension, or unknown causes), sepsis, anaphylaxis, and liver failure. Congestive heart failure is a particularly significant precipitant of renal failure. There are approximately 5 million Americans with congestive heart failure and approximately 400,000 new cases are reported annually. Many of these patients suffer from renal failure and must eventually undergo dialysis and/or await kidney transplant surgery.

While recovery of renal function sometimes occurs, there is substantial morbidity and mortality during the initiation, maintenance and recovery phases of acute renal failure. The recovery phase of acute renal failure, once complete, usually allows the resumption of normal renal function. Conditions that predispose to acute renal failure include ineffective renal perfusion, systemic hypotension of any cause, sepsis, major trauma, nephrotoxic insults such as aminoglycoside antibiotics and radiographic contrast agents, and obstruction to the urinary tract (M. Brezis et al . , The Kidney, B. M. Brenner et al . , eds . , W. B. Saunders (3rd ed. 1986) at pages 735-799) . Less commonly, acute renal failure may arise from certain types of glomerulonephritis and vasculitis. Since there are no specific therapeutic maneuvers that consistently and effectively hasten the recovery of renal function, once acute renal failure has already occurred, the management of patients with acute renal failure emphasizes the avoidance and/or correction of conditions such as hypoperfusion, hypotension, sepsis and nephrotoxic agents that predispose to acute renal failure (C. M. Kjellstrand et al . , Diseases of the Kidney, R. W. Schrier et al . , eds., Little Brown Co., Boston (4th ed. 1988) at pages 1501-1542) . Therefore, there is a continuing need for effective therapies to arrest or prevent acute renal failure in susceptible patients. Since hypoperfusion of the kidneys is at the root of many of the aforementioned causes of renal failure, increasing perfusion of the kidneys would seemingly underlie some of the solutions to such disease. A number of patents and scientific journal articles have been found describing various devices and methods which involve kidney perfusion. U.S. Patents Nos . 5,505,701, 5,711,754, 5,759,175, and 5,716,373 disclose intra-aortic balloon catheters for use in intra-aortic balloon pumping heart assist procedures. U.S. Patent No. 5,505,701 in particular, discloses an intra-aortic catheter apparatus for kidney perfusion and preservation which has a catheter with a tube having an intermediate part which forms a permeable zone located so that in an inserted condition of the catheter the permeable zone is exactly located at a renal parahiliar area, a distal balloon located at a distal caudal part of the tube and formed so as to obstruct circulation in an aorta when being inflated, a proximal balloon located at an end of the tube which is insertable over renal arteries and having such a diameter that upon inflation it also fully obstructs aortic circulation, the balloons being located at opposite sides the of the permeable zone and being separately controllable. U.S. Patent No. 4,714,460 discloses catheter feedback methods and systems for optimizing the infusion of a drug, such as a chemotherapeutic agent via retrograde perfusion through the venous side of the vascular network to a selectively determined portion of a solid tumor. The methods and systems may be used to treat tumors within kidneys. A feedback loop for practicing the method comprises two concentric balloon catheters capable of extensive maneuvering and selective placement within the venous drainage of the vascular system, creating a third in-vivo space for repeated perfusion of the selected portion of a diseased organ as often as desired, providing maximum exposure of the chemotherapy to the tumor with minimum exposure to any other portions of the patient's body.

U.S. Patent No. 4,701,160 discloses a medical catheter and a method for infusing blood into a patient. The medical catheter has first and second inlet openings, an outlet opening, a passageway connecting the openings, and a flexible valve member between the inlet openings. The valve member controls the size of the passageway between the inlet openings. The method includes inserting a conventional occlusion catheter into the medical catheter through the valve member and extending the tip of the occlusion catheter beyond the outlet opening of the medical catheter so that the blood vessel within the patient can be restrained. The device may be used to infuse bank blood or extravascular blood collected from the body into the abdominal aorta. U.S. Patent No. 5,210,098 discloses a therapeutic method for arresting or preventing acute kidney failure by administration of a non-toxic pyruvate salt to a patient in need of such treatment.

U.S. Patent No. 4,493,697 discloses a dynamically- augmenting pump system which incorporates a sealed liquid-filled catheter which is inserted into a vessel such as an artery, the pump system being operated in timed relation with the heart to aid the heart during episodes of impairment or failure of cardiac function by producing higher frequency pulsation or pressure waves within the blood during diastole and during the isometric contraction period of the heart. The catheter provides energy to maintain adequate blood flow through the healthy part of the myocardium and has a passage for injecting successive quantities of medication into the coronary arteries. The pump system also functions to penetrate the ischemic myocardial tissue with arterial blood and medication. The pump system may also be used to provide a flow of blood or substitute perfusates through selected tissues or body organs or to enhanced perfusion for other parts of the systemic circulatory system, for example, to prevent such detrimental effects as renal failure.

U.S. Patent No. 5,368,555 discloses an organ support system and method adapted for use with a patient and designed to modify the blood from the patient includes a control system, a venous line coupled to an output of a patient, an arterial line coupled to an input of the patient, and a metabolically active cell line inserted into a hollow fiber cartridge to form an organ assist device. Blood is passed through the organ assist device. A small flow is extracted from the extracapillary space to check the integrity of the organ assist device. With this closed loop arrangement, a proper fluid balance can be maintained for the patient without requiring any dialysate, and leaks from the cell line to the patient can be immediately detected and prevented from reaching the patient.

A recent scientific article entitled ^λRenal Perfusion with the Biomedicus Pump During Resection of an Abdominal Aortic Aneurysm" (JCC vol. 35, no. 6, 1992) disclosed a case report wherein a patient's kidney was perfused with oxygenated venous blood which was exported from the left femoral vein of the patient and oxygenated with a membrane oxygenator. A scientific article entitled ^λA new method for kidney perfusion in situ: application to dynamics of autoregulation" (Am. J. Physiol. Vol 242, 1982) disclosed a procedure wherein kidneys of dogs were perfused with arterial blood to study autoregulatory responses following step changes in renal artery flow.

None of the foregoing references, however, disclose a method or apparatus for antegrade perfusing the kidney with venous blood imported directly from a vein of the same body.

SUMMARY OF THE INVENTION

This invention is an apparatus and method for perfusing a mammalian kidney of a body with venous blood from the same body. The apparatus generally comprises at least one tubular member and a pump, the apparatus being configured to establish fluid communication between a renal artery lumen of a renal artery of the body and a vein lumen of a vein of the body, the pump being configured to interface with the tubular member and augment the flow of fluids, e.g. venous blood, through the tubular member from the vein to the renal artery. The inventive method generally comprises the steps of establishing a passageway through which fluid may pass from a vein of the body to a renal artery of the body, and pumping venous blood through the passageway from the vein to the renal artery at an appropriate flow rate .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a side view of a stylized variation of the inventive apparatus having stitched anastomoses.

Figure 2 depicts a side view of a stylized variation of the inventive apparatus having cannulated anastomoses . Figure 3 depicts a side view of a stylized variation of the inventive apparatus having synthetic-lumen quick- connect anastomoses.

Figure 4 depicts a side view of a stylized variation of the inventive apparatus having one synthetic-lumen quick-connect anastomosis and one live-lumen quick- connect anastomosis .

Figure 5 depicts a side view of a stylized variation of the inventive apparatus having perfusion catheter anastomoses .

Figure 6 depicts a side view of a stylized variation of the inventive apparatus having two T-graft anastomoses and an associated medicine pump.

Figures 7A-7E depict a method for installing the inventive device.

Figure 8 depicts a flow chart illustrating the flow of information in a variation of the inventive apparatus . Figure 9 depicts a flow chart illustrating the flow of information in a variation of the inventive apparatus. DETAILED DESCRIPTION OF THE INVENTION This invention is an apparatus and method for perfusing the kidney with venous blood from the same body. Referring to Figure 1, the apparatus (2) generally comprises one or more tubular members (8,10) configured to fluidly connect a vein (16) of the body with an artery (18) of the body upstream of the kidney of the body, preferably the renal artery, and a pump (12) interfaced with the tubular member (8,10) and configured to controUably pump venous blood from an export site (4) of the vein (16) to an import site (6) of the artery (18) . The connections formed between the ends (8,10) of the tubular member and the vein (16) and artery (18) , termed "anastomoses", may take several forms depending upon several factors of the particular variation, such as flow rate and device permanency. The tubular members, junctions thereof to vessels of the body, pump, and other related hardware which may comprise a variation may be customized for specific applications. A discussion of the suitable variations of particular components of the inventive apparatus is useful before preferred variations of the overall invention are described.

Tubular member portions:

The tubular member portions (8,10) may comprise live tissue autografts, live tissue allografts, live tissue xenografts, synthetic grafts, or a combination of these. Live graft materials may be preferred for long term device implantation, since such materials are intended to mimic the behavior of normal epithelium which forms other vessels of the body. Live tissue autografts may be formed form harvested saphenous veins, internal mammary arteries, or other vessels commonly used for such purposes. Live tissue allografts and xenografts, such as harvested and preserved veins from other animal bodies, may also be used. Live grafts vary greatly in mechanical properties and generally will not be structurally rigid or capable of resisting lumenal collapse under significant vacuum conditions. Where a graft may be subjected to vacuum conditions wherein pressures inside the lumen of the graft are less than pressures outside of the graft, a synthetic graft material with structural rigidity to prevent collapse is preferred. Synthetic grafts may also be preferred in variations configured for short-term installation, or in situations where uniformity of materials or particular material properties are desired. Synthetic grafts made from materials such as Dacron (RTM) , PTFE, or other polymers such as polyurethane or polyethylene may be used. Synthetic grafts may also comprise flexible metals, such as titanium or nickel-titanium, formed into threadlike support members or braided or woven patterns used to support other materials comprising a tubular member, as is known in the art of braided catheters and described, for example, in U.S. Patents Nos . 5,891,114, 5,782,811, and 5,057,092. Many suitable synthetic grafts are known to those skilled in the art, such as those described in U.S. Patents Nos. 5,880,090, 5,866,217, 5,843,173, 5,800,512 and 5,496,364.

Where a flexible graft material or live graft material is preferred, regions within the graft which may be subjected to low relative pressure and therefore be at risk of collapse may be structurally supported by a vacuum support member. The vacuum support member generally comprises an elongate stent which may be positioned within the lumen of the graft at risk of vacuum collapse. Many stents designed for supporting the lumens of vessels are known in the art, such as those described in U.S. Patents Nos. 5,507,771, 5,556,426, 5,607,445, 5,108,417, and 5, 747 , 128.

Adjacent vessels, more particularly the locations within veins from which venous blood is exported with the inventive device, may also be subjected to low relative pressure and therefore be at risk of collapse. Such regions may also be supported by vacuum support members such as the stents mentioned above for use in supporting grafts. More preferably, a stent-based implantable flow diversion device having a stent structure with a side port configured to facilitate the diversion of flows to an adjacent graft may be used as a vacuum support member in an adjacent vessel. Suitable stent-based implantable flow diversion devices are described in Applicant's copending application for "Implantable Flow Diversion Device" (attorney docket number 3659-5) , and "Anastomosis Device and Method" (attorney docket number 3659-8), both of which are incorporated by reference in their entirety. Figures 2-6 depict several variations of graft and intact vessel subassemblies configured to withstand vacuum pressure situations without collapse. Figure 2 shows a relatively stiff polymeric cannula tubing (8) attached to an unsupported vein (16) . The tissue forming the intact vein provides enough support to facilitate limited vacuum pressures within the cannula tubing, but may collapse under larger vacuum pressures. Figure 3 shows a braid-supported tubing member (8) attached to a vein (16) supported by a stent-based implantable flow diversion device (21) which, in this case, has sensors or sensor portions (26, 28) coupled to its stent construct. Figure 4 shows a stent-supported live graft member (8) attached to a vein (16) supported by a stent-based implantable flow diversion device (22) .

P-amps : The pump (12), as shown in Figures 1-6, may be an implantable pump, or may be an extracorporeal unit, such as those designed for cardiopulmonary bypass apparatuses, depending upon the particular application of the inventive apparatus. Various suitable pump configur- ations are known in the art, including axial flow pumps, a centrifugal pumps, and roller pumps. Preferred pumps are capable of graduated flow rate adjustment up to 3 liters per minute. Many suitable extracorporeal pumps are known to those skilled in the art, such as those described in U.S. Patents Nos. 5,803,720, 5,759,017, 5,746,709, 5,089,016, and 5,092,844. Suitable implantable pumps include those described in U.S. Patents Nos. 5,707,218, 5,840,070, 5,108,426, 4,557,673, 4,666,443, 4,457,673, and 4,756,302. Depending upon the particular pump, the interface between pump and tubular member may vary. In the case of peristaltic or roller pumps, portions of the pump will be configured to squeeze the intact tubular member, the pump having no physical contact with venous blood being pumped through the tubular member. In the case of other pumps such as many centrifugal pumps, the tubular member may be divided into two portions so the pump can be attached therebetween in a configuration where it will have direct contact with the venous blood being transported, as required by the particular pump design.

Anastomoses types :

As stated above, the anastomoses may take several forms, depending upon the particular application. For short term installations, venous and arterial cannulas, such as those described in U.S. Patents Nos. 5,769,828, 5,762,624, and 5,752,970, may be used. A cannulated anastomosis generally comprises a cannula placed through a small aperture in a vessel and sutured in place using standard techniques, such as a purse-string suture. The aperture in the vessel may be formed using a sharpened instrument such as a trocar or other standard hole- forming surgical instrument.

Suitable anastomoses may also be formed using standard suturing techniques such as those described in U.S. Patent No. 5,452,733. A sutured anastomosis generally comprises a graft end matched to an aperture created in a vessel with stitches placed around the perimeter of the junction of the aperture and graft end, the stitches piercing both the vessel and the graft end. An anastomosis may also be formed using a perfusion catheter such as those described in U.S. Patents Nos. 4,994,745 and 5,295,995. A perfusion catheter anastomosis generally comprises a perfusion catheter end, preferably an expandable end configured to expand for fixation without totally occluding the surrounding vessel, placed within a vessel, the proximal end of the catheter and extending out through an aperture created in the vessel wall, the aperture being configured to prevent leakage around the catheter body using, for example, a purse-string suture through the tissue defining the aperture and around the catheter body.

Devices may also be used to create device-formed synthetic-lumen or live-lumen anastomoses. Several suitable anastomosis devices are known in the art, such as those described in U.S. Patents Nos. 4,624,255,

4,523,592, or 4,366,819, or in Applicant's copending applications for "Implantable Flow Diversion Device" (attorney docket number 3659-5), and "Anastomosis Device and Method" (attorney docket number 3659-8). A device- formed synthetic-lumen anastomosis generally comprises a mechanical device configured to join a graft lumen with a vessel lumen, the device forming an intermediate lumen itself which is generally not lined with an inner lining of live graft tissue so that blood flowing across the completed anastomosis flows through lumens which are not lined with live graft tissue. A device-formed live-lumen anastomosis generally comprises a mechanical device configured to join a graft lumen with a vessel lumen in a manner wherein blood flowing across the completed anastomosis flows through lumens which are generally lined only with live graft tissue.

One variation of a device-formed synthetic-lumen anastomosis described in Applicant's copending application for "Implantable Flow Diversion Device" (attorney docket number 3659-5) , is a T-graft end-to-end anastomosis. A T-graft end-to-end anastomosis generally comprises an end-to-end anastomosis formed using standard suturing techniques or devices for joining two graft ends, such as those disclosed in U.S. Patent No. 5,314,436, between the end of a graft member and the end of a T-graft member which is fluidly connected with the lumen of an adjacent vessel and is coupled to a stent installed in the adjacent vessel, the T-graft extending out of an aperture created in the adjacent vessel in a configuration where it may be joined to the end of the graft member. In the case of a bifurcated T-graft, two T-graft end-to-end anastomoses may be formed with the same adjacent vessel at the same location.

Control System:

The inventive apparatus may also comprise a control system having data acquisition capabilities, output signalling capabilities, or both. A suitable data acquisition control system generally comprises at least one sensor, a data acquisition device, and a power source for activating the sensor and generating signals, the sensor having an conductive lead configured to communicate signals to the data acquisition device, the data acquisition device being configured to communicate with or function as a monitor for important variables such as hematocrit level, blood flow rate, or blood oxygen level. Suitable sensors, including oxygen sensors such as those comprising a light emitting device, pressure sensors such as those comprising a piezoelectric transducer or a crystalline silicon chip, fluid flow sensors such as those based upon Doppler transducer theory, hematocrit sensors, temperature sensors, heart electrical signal sensors, biochemical sensors, pH level sensors, and blood electrolyte sensors are further discussed in U.S. Patent application for "Instrumented Stent" (attorney docket number 3659-6) , which is incorporated by reference in its entirety.

A suitable output signalling control system generally comprises an output signalling device, an operator, a power source for generating signals, and conductive leads for transmitting output signals, the output signalling device being configured for receiving instruction signals from the operator and sending electronic signals to control some operational aspect of the apparatus, such as a pump rate, and a power source for generating output signals. In the case of a data acquisition and output signalling control system, a single device may be configured to receive signals from sensors, receive instruction signals from an operator, and send signals to remote controls.

Data acquisition and/or output signalling devices may be implantable and may comprise an implantable battery or power source. The apparatus may additionally comprise a transcutaneous energy transfer device for recharging an implantable battery or powering portions of the apparatus. Several such transcutaneous energy transfer, or "TET" devices, are known in the art, such as those described in U.S. Patents Nos. 5,755,748, 5,702,431, and 5,350,413.

The operator sending instruction signals to the control system may be a person using a remote control device in real time, a device having programmable logic and signal transmission capabilities for automated control given certain input variables and program logic, or an implantable programmable logic device which may be configured to have direct electrical contact with the control system and even reside within the same mechanical construct as the output signalling device.

In cases where the data acquisition/output signalling device resides in a location different from that of the operator, the device and operator are preferably capable of sending and/or receiving signals using wireless signal transmission technology which preferably is capable of transcutaneous transmission. In the case of a control system having only data acquisition capability, the data acquisition device is preferably configured to transmit acquired signal data to a remotely located monitoring device using similar wireless signal transmission technology, also preferably capable of transcutaneous transmission. Sophisticated control systems with data acquisition and output signalling capabilities, as well as transcutaneous signal transmission capabilities, are well known in the art of implantable defibrillators and are described in references such as U.S. Patent No. 5,314,450.

Suitable sensors and devices for locating sensors within vascular system lumens are described in copending application by Applicant for "Instumented Stent"

(attorney docket number 3659-6) , which is incorporated by reference in its entirety. An instrumented stent generally comprises a stent with at least one sensor coupled thereto and having a sensor lead extending therefrom. An instrumented stent may also be used for vacuum support of a surrounding lumen as is described above since it comprises a stent structure, or configured for flow diversion as in an implantable flow diversion device, as is also described above (in such case, being more accurately described as an instrumented implantable flow diversion device, as is disclosed in Applicant's copending application for "Implantable Flow Diversion Device", attorney docket no. 3659-5).

The apparatus may also comprise a medicine pump having at least one reservoir containing a medicine which is fluidly connected to the tubular member of the apparatus, or to one of the associated vessels, particularly to the renal artery. The fluid connection may be accomplished using a small tubular member, such as a polymeric tube, which is anastomosed to the lumen of the tubular member or associated vessel using standard techniques . The medicine pump may be remotely controllable or programmable and may be implantable. Suitable pumps are known in the art and are described in references such as U.S. Patents Nos. 5,820,589, 5,207,666, and 5,061,242.

Referring again to Figure 1, a schematicized variation of the inventive apparatus (2) is shown having a sutured export end (8) anastomosis (36) , a sutured import end (10) anastomosis (36) , an implantable pump (12), and an instrumented stent' (34) having sensors (26, 28) coupled thereto. In the depicted variation, both the export end (8) and import end (10) of the tubular member comprise harvested saphenous vein autograft. The pump (12) is generally operated at appropriately low flow rates in this variation, preferrably less than 2.0 liters per minute, to prevent vacuum collapse of the export end (8) or the vein (16) export location (4), which, in the depicted variation, is a section of the inferior vena cava. Alternatively, the export end (8) and vein export location (4) may be fitted with vacuum support structures (not shown) , such as stents, to prevent vacuum collapse and thus facilitate greater flow rates. A lead (52) configured to facilitate signal transfer between the sensors (26, 28) of the instrumented stent (34) and a data acquisition and/or control system (not shown) is depicted extending out a small surgically-created aperture (44), or arteriotomy, in the artery (18). Also depicted is a pump lead (42) configured to transfer signals between the pump and a data acquisition and/or control system (not shown) . Referring to Figure 2, another variation of the inventive apparatus is depicted having cannulated anastomoses (39, 41) and polymeric tubular member export (8) and import (10) ends. This variation, preferred for short term apparatus installation, may be installed relatively quickly using standard techniques for placing venous (39) and arterial (41) cannulae . This variation comprises an extracorporeal pump (12) and relatively long tubular member export (8) and import (10) ends (shortened for illustration purposes) . This variation also preferably comprises at least one sensor (26, 28), preferably for monitoring blood oxygen content, located downstream of the arterial import location (6) and coupled to an instrumented stent (34). A signal conduction lead (52) facilitates signal transmission between the sensor (26, 28) and an extracorporeal data acquisition and monitoring system (not shown) . The extracorporeal pump (12) of this variation is preferably controlled by a control system integrated with the data acquisition and monitoring system for the sensor, so that venous blood perfusion flows may be automatically or manually adjusted to provide a desired oxygen content in the region of the instrumented stent (34) .

Referring to Figure 3, a variation of the inventive device is depicted having device-formed synthetic-lumen anastomosis devices, as described in Applicant's copending application for "Anastomosis Device and Method" (attorney docket number 3659-8). Also forming portions of the anastomosis constructs are structural implants (21, 22) placed within the venous export location (4) and arterial import location (6). More particularly, the depicted variation comprises an instrumented (26, 28) implantable flow diversion device (21) placed at the venous export location (4) and a side port flow diversion device (22) placed at the arterial import location (6) . Such implantable flow diversion devices are described in Applicant's copending application for "Implantable Flow Diversion Device" (attorney docket number 3659-5) . An instrumented stent (34) having sensors (26, 28) for monitoring characteristics of flows therethrough is positioned downstream of the arterial import location (6) . The depicted variation also comprises two structures for preventing lumen collapse under vacuum conditions . The aforementioned instrumented implantable flow diversion device (21) comprises a stent structure which, besides serving as a flow diverter and anastomosis structure support, supports the surrounding vein (4) .

The export end (8) of the tubular member is supported by a braided nickel-titanium vacuum support structure (58) embedded between two layers of the export end (8) of the tubular member, which in this variation comprises a flexible polymer such as polyethylene. Referring to Figure 4, a variation of the inventive apparatus is shown having a device-formed synthetic-lumen anastomosis (37) with sensors (26, 28) at the export end (8) and a device-formed live-lumen anastomosis (38) at the import end (10) of the tubular member. The phrase "device-formed" is used in reference to an anastomosis formed via the utilization of a mechanical device other than traditional suturing techniques. Devices for making device-formed synthetic-lumen and live-lumen anastomoses are described in Applicant' s copending application for "Anastomosis Device and Method", attorney docket number

3659-8. In the depicted variation, the export end (8) is coupled to a vacuum support structure (58), here an expandable stent. The vein export region (4) is also supported, in this variation by an implantable flow diversion device (22) which comprises a stent structure having a side port.

The depicted variation also comprises an implantable data acquisition/output signalling device (40) which is configured to communicate transcutaneously with an extracorporeal monitor/operator (43) . Leads (42, 52, 56) for transmitting signals between the data acquisition / output signalling device (40) and sensors (26, 28) and pump (12) are also depicted. The leads (42, 52, 56) and data acquisition/output signalling device (40) are configured to interface using sealed configurations known in the art of implantable defibrillators and cardiac pacing and described, for example, in references such as A Practical Guide to Cardiac Pacing, 4^th Edition, Little Brown & Company, 1994. The depicted control system also comprises an implantable power supply, more specifically a battery (99) such as those known in the art of cardiac pacing and defibrillation, which is coupled to the data acquisition/output signalling device (40) and configured to assist in the transmission and storage of signals .

Referring to Figure 5, a variation of the inventive apparatus is depicted having two perfusion catheter anastomoses (71, 72) and two associated inflatable balloons (69, 70) which are configured to allow for perfusion flow through the associated catheter tubes (60, 61) as well as other flows existing within the artery (18) and vein (16) . In other words, the balloons (69, 70) , when inflated using the depicted inflation lumen tubing (67, 68), do not wholly occlude flows normally existing within the artery (18) and vein (16) notwithstanding the perfusion flows through the catheter tubes (60, 61) . The perfusion catheter anastomoses (71, 72) , formed by surgically creating an aperture, inserting a balloon-end perfusion catheter, and sealing the anastomosis with a purse-string suture (not shown) or similar technique, are generally considered to be a less permanent solution than others discussed herein, such as the implantable device-formed anastomoses shown in Figure 4 (37, 38) . Also depicted in Figure 5 is a pump lead (42) configured for connecting the pump (12) to a control system (not shown) . Referring to Figure 6, a variation of the inventive apparatus is depicted having two T-graft anastomoses (58, 58) formed using known polymeric adhesives at the junction between the preferably polymeric T-grafts (63, 64) and catheter tubing portions (60, 62) associated with the pump (12). T-grafts (63, 64 ) , T-graft anastomoses (57, 58), and T-graft implantable flow diversion devices (65, 66) are further described in U.S. Patent applications for "Implantable Flow Diversion Device", attorney docket 3659-5, and "Anastomosis Device and Method", attorney docket 3659-8, each of which is incorporated by reference in its entirety. Also depicted in fluid attachment with one of the catheter tubular members (62) via another catheter tubular member (61) is an implantable medicine pump (59) . Both of the pump (12) and medicine pump (59) are depicted having leads (42, 73) attached thereto which are configured for establishing communication between these pumps and a control system (not shown) .

Figures 7A through 7E depict a met-hod of installing a variation of the inventive apparatus similar to that shown in Figure 4. For illustrative efficiency, each of Figures 7A-7E depicts an installation step for both the arterial side of the device and the venous side of the device; the steps would preferably be conducted sequentially rather than simultaneously in the surgical setting. Referring to Figure 7A, a delivery catheter

(32) is shown in the target artery (18) with a guidewire

(33) pushing an instrumented stent (34) out the end of the delivery catheter (32) at a location upstream of the kidney and downstream of the arterial import location (6) . Similarly, another delivery catheter is shown in the target vein (16) with a guidewire (33) pushing an implantable flow diversion device (22) having a side port

(23) out the end of the delivery catheter (32) at the venous export location (4) .

Referring to Figure 7B, a synthetic-lumen anastomosis device (37) is shown in a position for being implanted through the side port (23) of the flow diversion device (22) at the venous export location (4). After a trocar (not shown) makes an small aperture in the vein (16) at the location of the side port (23) , the synthetic-lumen anastomosis device (37) is pushed through the side port (23) to a position where the extensions

(24) of the device (37) extend outwardly within the lumen of the vein (16) . The device (37), with synthetic graft intact and clamped (30), is then pulled away from the vein (16) and the associated fastener (25) used to place the vein (16) wall in compression between the extensions (24) and the fastener (25), as depicted in Figure 5C . Further description of the operation of such anastomosis device is found in Applicant's copending application for "Anastomosis Device and Method", attorney docket number 3659-8, which is incorporated by reference in its entirety.

The arterial anastomosis is similar formed using a device, in the depicted instance a live-lumen anastomosis device (38) . After a trocar (not shown) makes an small aperture in the artery (18) at the arterial import location (6), the insertion structure (31) of the device (38) is pushed through the aperture to a position where the radial extensions (80) may expand outward within the lumen of the artery (18) . As depicted in Figure 7C, the insertion structure (31), with live graft (50) intact, is then pulled away from the artery (18) while threadlike and external support saddle components (not shown) are installed, placing the artery (18) wall in compression between the radial extensions (80) and the external support saddle (not shown). As described in U.S. Patent application for "Anastomosis Device and Method", attorney docket number 3659-8, the insertion structure (31) is then detached, leaving a clamped (30) device-formed live- lumen anastomosis (38) as shown in Figure 7D. As shown in Figure 7E, the export (8) and import (10) ends of the tubular member are then connected with the pump (12) after standard flushing and gas bubble removal techniques have been applied.

Referring to Figure 8, a flow chart is depicted for a control system having data acquisition capability. The chart shows that information flows from a sensor to a data acquisition device, which in this case is capable of transmitting data transcutaneously through the skin (70) to the monitor. Figure 9 depicts a more complex control system having data acquisition and output signalling capabilities . The chart shows that information flows from a sensor and operator to a data acquisition/output signalling device. Information then flows from the data acquisition / output signalling device a blood pump, a monitor, and potentially a medicine pump. Dashed lines indicate that the blood pump and medicine pump may also have sensors which may input data to the data acquisition / output signalling device. The chart shows that the monitor and operator are located transcutaneously (70) from the other componentry. Each of the U.S. Patent documents, U.S. patent application documents, foreign Patent documents, and scientific reference documents (including texts and scientific journal articles) referred to in the text of this document is incorporated by reference into this document in its entirety.

Many alterations and modifications may be made by those of ordinary skill in the art without departing from the spirit and scope of this invention. The illustrated embodiments have been shown only for purposes of clarity. These examples should not be taken as limiting the invention defined by the following claims, said claims including all equivalents now or later devised.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for perfusing a mammalian kidney of a body with venous blood from said body, said apparatus comprising: a. at least one tubular member; and b . a pump; said apparatus being configured to establish fluid communication between a renal artery lumen of a renal artery of said body and a vein lumen of a vein of said body and augment the flow of fluids therebetween.

2. The apparatus of claim 1 wherein said tubular member has a first end and a second end, one of said first and second ends forming an anastomosis with said renal artery.

3. The apparatus of claim 2 wherein said anastomoses is a sutured anastomosis.

4. The apparatus of claim 2 wherein said anastomoses is a cannulated anastomosis.

5. The apparatus of claim 2 wherein said anastomosis is a perfusion catheter anastomosis.

6. The apparatus of claim 2 wherein said anastomosis is a device-formed synthetic-lumen anastomosis .

7. The apparatus of claim 2 wherein said anastomosis is a device-formed live-lumen anastomosis.

8. The apparatus of claim 1 wherein said at least one tubular member forms a T-graft end-to-end anastomosis with a T-graft member, said T-graft member being in fluid communication with said renal artery lumen.

9. The apparatus of claim 1 wherein said tubular member has a first end and a second end, one of said first and second ends forming an anastomosis with said vein.

10. The apparatus of claim 8 wherein said anastomosis is a sutured anastomosis.

11. The apparatus of claim 8 wherein said anastomosis is a cannulated anastomosis.

12. The apparatus of claim 8 wherein said anastomosis is a perfusion catheter anastomosis.

13. The apparatus of claim 8 wherein said anastomosis is a device-formed synthetic-lumen anastomosis .

14. The apparatus of claim 8 wherein said anastomosis is a device-formed live-lumen anastomosis.

15. The apparatus of claim 1 wherein said at least one tubular member forms a T-graft end-to-end anastomosis with a T-graft member, said T-graft member being in fluid communication with said vein lumen.

16. The apparatus of claim 1 wherein said at least one tubular member comprises a graft material selected from the group consisting of a tissue autograft, a tissue allograft, and a tissue xenograft.

17. The apparatus of claim 1 wherein said at least one tubular member comprises a vein graft or an artery graft.

18. The apparatus of claim 1 wherein said at least one tubular member comprises a synthetic material.

19. The apparatus of claim 16 wherein said at least one tubular member comprises a flexible metal or a polymer material.

20. The apparatus of claim 1 wherein said at least one tubular member comprises a vacuum support member configured to prevent collapse of said at least one tubular member under vacuum conditions .

21. The apparatus of claim 1 further comprising a vacuum support member configured to prevent collapse of said vein under vacuum conditions.

22. The apparatus of claim 1 wherein said pump is a pump selected from the group consisting of a centrifugal flow pump, a roller pump, and an axial flow pump.

23. The apparatus of claim 1 wherein said pump is implantable .

24. The apparatus of claim 1 wherein said at least one pump is capable of pumping up to 3 liters of blood per minute.

25. The apparatus of claim 1 further comprising a flow sensor, said flow sensor being associated with said at least one tubular member and configured to monitor the flow of fluids within said at least one tubular member.

26. The apparatus of claim 25 wherein said flow sensor comprises a Doppler transducer.

27. The apparatus of claim 1 further comprising an artery sensor, said artery sensor being associated with said renal artery and configured to monitor the characteristics of fluids flowing therein.

28. The apparatus of claim 27 wherein an instrumented stent is used to position said artery sensor within the lumen of said renal artery.

29. The apparatus of claim 27 wherein said artery sensor is a sensor selected from the group consisting of an oxygen sensor, a pressure sensor, a fluid flow sensor, a hematocrit sensor, a temperature sensor, a heart electrical signal sensor, a biochemical sensor, a pH level sensor, and a blood electrolyte sensor.

30. The apparatus of claim 27 wherein said artery sensor comprises a light emitting device.

31. The apparatus of claim 27 wherein said artery sensor comprises a Doppler transducer.

32. The apparatus of claim 27 wherein said artery sensor comprises a piezoelectric transducer.

33. The apparatus of claim 27 wherein said artery sensor comprises a crystalline silicon chip.

34. The apparatus of claim 1 further comprising a medicine pump, said medicine pump having a fluid reservoir which is fluidly connected to fluids flowing within said apparatus.

35. The apparatus of claim 34 wherein said medicine pump is implantable.

36. The apparatus of claim 1 further comprising a control system, said control system being operable to receive signals from at least one sensor.

37. The apparatus of claim 36 wherein said control system is further operable to send signals to said pump.

38. The apparatus of claim 37 wherein said control system is further operable to receive signals from an operator.

39. The apparatus of claim 38 wherein said operator is a programmable logic device.

40. The apparatus of claim 38 wherein said control system is implantable and is operable to receive signals transcutaneously from an operator.

41. The apparatus of claim 40 further comprising an implantable battery.

42. The apparatus of claim 41 wherein said battery is transcutaneously rechargeable.

43. A method of perfusing a mammalian kidney of a body with venous blood from the same body comprising the steps of: a. establishing a passageway through which fluid may pass between a vein of said body and a renal artery of said body; b. pumping venous blood through said passageway from said vein to said renal artery at a controlled flow rate.

44. The method of claim 43 further comprising monitoring the oxygen level of blood within said renal artery.

45. The method of claim 43 further comprising monitoring the flow of blood in said passageway.

46. The method of claim 43 further comprising monitoring pressure in said renal artery.

47. The method of claim 43 further comprising monitoring heart electrical signals.

48. The method of claim 43 further comprising monitoring biochemical levels in said renal artery.

49. The method of claim 44 further comprising adjusting said controlled flow rate to maintain a determined oxygen level of blood within said renal artery.

50. An apparatus for perfusing a mammalian kidney of a body with venous blood from said body, said apparatus comprising: a. an export tubular member; b. an import tubular member; and c . a pump; said export tubular member being configured to establish fluid communication between a vein lumen of a vein of said body and said pump, said import tubular member being configured to establish fluid communication between said pump and a renal artery lumen of a renal artery of said body.

51. The apparatus of claim 50 further comprising an artery sensor, said artery sensor being associated with said renal artery and configured to monitor the characteristics of fluids flowing therein.

52. The apparatus of claim 51 wherein an instrumented stent is used to position said artery sensor within the lumen of said renal artery.

53. The apparatus of claim 51 wherein said artery sensor is a sensor selected from the group consisting of an oxygen sensor, a pressure sensor, a fluid flow sensor, a hematocrit sensor, a temperature sensor, a heart electrical signal sensor, a biochemical sensor, a pH level sensor, and a blood electrolyte sensor.

54. The apparatus of claim 50 further comprising a control system, said control system being operable to receive signals from at least one sensor.

55. The apparatus of claim 54 wherein said control system is further operable to send signals to said pump.