WO2001008576A2

WO2001008576A2 - Laser method and apparatus for treatment of tissue

Info

Publication number: WO2001008576A2
Application number: PCT/US2000/020926
Authority: WO
Inventors: Edward L. Sinofsky; Jeffrey W. Brown; Lincoln S. Baxter
Original assignee: Cardiofocus, Inc.
Priority date: 1999-07-30
Filing date: 2000-07-31
Publication date: 2001-02-08
Also published as: WO2001008576A9; WO2001008576A3; AU6616700A

Abstract

The present invention describes methods and apparatus for phototherapeutically treating, e.g., ablating, coagulating, and/or phototherapeutically modulating a target tissue, e.g., cardiac tissue. The methods include introducing a flexible elongate member into a predetermined tissue site with the flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending therebetween. A portion of the distal end of the flexible elongate member contains holes, such that the porous portion is positioned proximate to the tissue site. A solution is injected through the porous portion, thereby diluting body fluid(s) and/or blood about the tissue site. An energy emitter is slidably positioned through the lumen proximate to the tissue site and energy is transmitted through the holes of the distal end of the elongate member through the energy emitter.

Description

LASER METHOD AND APPARATUS FOR TREATMENT OF TISSUE

FIELD OF THE INVENTION

The present invention is directed to systems and methods for ablating interior regions of the heart for treatment of cardiac abnormalities. The methods and apparatus include the ability to perfuse an area with a solution prior to or during treatment with ablative energy, thereby diluting blood and/or body fluids which would otherwise reduce or obstruct the ablative energy from reaching the tissue site with nonabsorbing or semiabsorbing fluids.

BACKGROUND OF THE INVENTION

Destruction of cellular tissues in situ has been used in the treatment of diseases and medical conditions alone or as an adjunct to surgical removal procedures. These methods are often less traumatic than surgical procedures and may be the only alternative where surgical procedures are unfeasible. One example of a technique which is less invasive than traditional surgery is catheterization. A catheter can be inserted into an artery or vein and guided to a site for treatment. The treatment site is generally distant from the insertion point of the catheter. Typically, the catheter enables the physician to place a device proximate to the treatment site such that the tissue can be treated with an energy emitting device.

Energy emitting devices used with catheters include microwave, radio frequency, cryoscopic and acoustical (ultrasound) devices catheters to destroy malignant, benign and other types of aberrant cells in tissues from a wide variety of anatomical sites and organs. Tissues sought to be treated include isolated carcinoma masses and, more specifically, organs such as the prostate, bronchial passage ways, passage ways to the bladder, passage ways to the urethra, and various passage ways into the thoracic area, e.g., the heart.

One of the challenges in using a catheter is controlling the position and placement of the distal portion of the catheter from a remote location outside of the subject's body. For example, careful and precise control over the catheter is required during critical procedures which ablate tissue within the heart. Such procedures are termed

"electrophysiological" therapy and are becoming widespread for treatment of cardiac rhythm disturbances. During these procedures, an operator guides a catheter through a main artery or vein into the interior of the heart which is to be treated and contacted with an energy emitting device. The treatment of the delicate tissue, such as heart tissue, must be accomplished with great precision as the danger of also affecting adjacent tissue is always present, especially when the process occurs remotely at the distal end of a relatively long catheter.

In general, the energy emitter is required to contact the tissue surface to effect therapeutic treatment to the area. Variations in tissue characteristics, for example highly trabeculated tissue on the atrial wall can result in non-uniform and/or incomplete treatment. For example, absorption characteristics of normal tissue can be much different from tissue that is heavily scarred. As a result, an electrical conduction block is not achieved.

Blood and/or other body fluids further complicate treatment methods by interfering with the transmission of energy to the treatment site. For example, the energy emitted from the catheter can be scattered or be absorbed by blood and other body fluids between the energy emitter and the tissue treatment site. Coagulation of blood or body fluids about the treatment site can further impede the beneficial effect(s) of the transmitted energy. The general approach, thus far, has been to minimize the amount of blood or body fluid between the energy emitter and the tissue site by contacting the energy emitter to the tissue to be treated. However, this can lead to adhesion between the device, thereby causing charring and/or disruption of the tissue.

Therefore, a need exists for a method and an apparatus which directs beneficial energy onto a specific treatment area wherein surrounding tissue is not degraded, the energy source does not need to be in direct contact with the tissue, and blood and body fluids are not coagulated or destroyed.

SUMMARY OF THE INVENTION

The present invention circumvents the problems described above by delivering energy, e.g., laser light or other energy, to a targeted site without requiring direct contact with the targeted tissue. This indirect contact with the targeted tissue provides the advantage that irregular tissue surfaces can be treated with long lesions more readily and completely. The invention also provides the advantage that damage to surrounding tissues is minimized or eliminated. In one embodiment, the present invention is drawn to an apparatus for phototherapy that operates by ablation, coagulation and/or phototherapeutic processes in tissue. The apparatus, e.g., a catheter, includes a flexible elongate member having a proximal end, a distal end and at least one longitudinal lumen extending therebetween, wherein a portion of the distal end of the flexible elongate member is porous, e.g. holes. A proximal portion and the lumen permit the delivery of a solution to the target site. The apparatus further includes an energy emitter for transmitting energy to the distal end of the elongate member. The energy emitter is adapted to be coupled to an energy source transmits energy, e.g., laser energy, e.g., between about 300 nm and about 2.4 micrometers, through the energy emitter. In another aspect, the present invention is drawn to a catheter end portion suitable for perfusion fluids into a tissue cavity or body lumen which requires treatment. The catheter end portion includes a flexible elongate member having a proximal end, a distal end and at least one lumen extending there between. A portion of the distal end of the flexible elongate member is porous. Optionally, the catheter end portion is detachable. In still another aspect, the present invention is drawn to methods for phototherapy by ablating, coagulating, or phototherapeutically modulating a target tissue. The methods include introducing a flexible elongate member into a predetermined tissue site. The flexible elongate member has a proximal end, a distal end and at least one lumen extending therebetween. A portion of the distal end of the flexible elongate member contains pores, e.g., holes, such that the porous portion is directed toward the tissue site, e.g., the energy emitter remains within the distal end of the flexible member (not in direct contact with the tissue, blood, or body fluids). A solution is introduced to the site via the lumen and through the holes, thereby diluting or eliminating any body fluid or blood about the tissue site such that the absoprtion of energy by the blood or body fluid(s) is reduced. This dilution of blood allows the photonic energy to be delivered more effectively and deeper into the tissue. It also enhances the ability to create lesions from a non-contact position. An energy emitter can be slidably positioned in the lumen proximate to the tissue site and energy is transmitted to the distal end of the elongate member, e.g., the porous portion, through the energy emitter. During this treatment, which can be therapeutic or prophylactic, the target tissue is phototherapeutically treated without damaging the surrounding tissue.

In yet another aspect, the present invention is drawn to methods for phototherapy by ablation, coagulation, and/or phototherapeutically modification of a trabecular surface in vivo. The methods include introducing a flexible elongate member into the right and/or left atrium. The flexible elongate member has a proximal end, a distal end and at least one longitudinal lumen extending therebetween. A portion of the distal end of the flexible elongate member is porous, such that the porous portion is positioned proximate to the trabecular surface of the right atrium. A solution is injected through the holes, thereby diluting body fluid(s) and/or blood about the trabecular surface. An energy emitter can be slidably positioned through the lumen proximate to the trabecular surface and energy is transmitted to the porous portion of the distal end of the elongate member through the energy emitter. Advantageously, the trabecular surface is phototherapeutically treated uniformily and completely without damaging the surrounding tissue. Such treatment provides a lesion(s), e.g., linear lesion(s), on the surface of the atrial wall which impedes generation and/or propagation of aberrant electrical wavefronts which are causative or associated with heart conditions, e.g., arrhythmia, atrial fibrillation, atrial flutter. In a further aspect, the present invention is drawn to methods for treating or preventing atrial fibrillation by phototherapy. The methods include introducing a flexible elongate member into the right atrium. The flexible elongate member has a proximal end, a distal end and at least one longitudinal lumen extending therebetween. A portion of the distal end of the flexible elongate member is porous, such that the porous portion is positioned proximate to atrial tissue. A solution is expelled through the porous portion, thereby diluting or eliminating body fluid(s) and/or blood about the atrial tissue. An energy emitter can then transmit energy to the atrial target site that has been cleared of blood and or other body fluids. Advantageously, the atrial tissue is ablated, coagulated and/or phototherapeutically modulated without damaging the surrounding tissue. In another aspect, the flexible elongate member has a preset curve to match and/or shape the atrial or ventricular wall when pushed into contact with the wall of the chamber.

The methods and apparatus of the invention can be used prophylactically or therapeutically.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages and features of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is a cross-section view of a steerable catheter of an embodiment of the invention having an energy emitter disposed within the lumen of the porous portion of a flexible elongate member;

FIG. 2 is a cross-section view of a steerable catheter of an embodiment of the invention having an energy emitter disposed within the lumen of a catheter end fixedly attached to the distal end of a flexible elongate member;

FIG. 3 is a cross-section view of the catheter body taken along the lines 3-3 of FIGS. 1 and 2;

FIG. 4 is a cross-section view of a steerable catheter of an embodiment of the invention having an energy emitter disposed within the lumen of the porous portion of a flexible elongate member having a second lumen;

FIG. 5 is a cross-section view of a steerable catheter of an embodiment of the invention having an energy emitter disposed within the lumen of a catheter end fixedly attached to the distal end of a flexible elongate member having a second lumen;

FIG. 6 is a cross-section view of the catheter body taken along the lines 6-6 of FIGS. 4 and 5;

FIG. 7 is a cross-section view of a preferred embodiment of the invention; FIG. 8 is a schematic block diagram of a laser tissue treatment system according to the present invention; and

FIG. 9 is a detailed schematic diagram of a reflectance monitor for use in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The features and other details of the invention will now be more particularly described and pointed out in the claims. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention. The principle features of this invention can be employed in various embodiments without departing from the scope of the invention.

The present invention is based, at least in part, on a discovery that the present invention can be used for phototherapeutically modifying tissue by inducing hyperthermia, coagulation and/or phototherapeutic processes in tissue, e.g., ablation, degradation, or destruction of tissue, at a specified site in tissue without harming the surrounding tissue. The results are surprising and unexpected since the efficiency and efficacy of light energy, e.g., coherent light, is generally diminished by interaction(s) with blood and/or body fluids which surround a tissue site to be treated. Prior to this invention, the energy emitter, e.g., a laser source, ultraviolet light, microwave radiation, radio-frequency, etc., has generally been required to contact the tissue to effect a therapeutic or prophylactic treatment. In contrast to known apparatuses and methods, the present invention does not require direct contact between the energy source, e.g., a laser source, and the tissue site to be treated. Moreover, the methods and apparatus of the invention circumvent the drawbacks of having blood or body fluid coagulate, degrade or be destroyed in the treatment area proximate to the targeted tissue due to interactions with the applied energy.

In one embodiment, the present invention is drawn to an apparatus for phototherapeutically inducing ablation, coagulation and/or phototherapeutic processes in tissue. The apparatus, e.g., a catheter, includes a flexible elongate member having a proximal end, a distal end and at least one lumen, e.g., a longitudinal lumen, extending therebetween. A portion of the distal end of the flexible elongate member is porous. An energy emitter can be slidably extended within lumen for transmitting energy to the distal end, e.g., a porous portion, of the elongate member, with the energy emitter having a proximal end and a distal end. An energy source is in communication with the proximal end of the energy emitter and is effective to transmit energy, e.g., laser energy, e.g., between about 300 nm and about 2.4 μm, preferably between about 800 and about 810 nm, through the energy emitter. In one embodiment, the porous portion is non-inflatable. In another aspect, the present invention is drawn to a catheter end portion suitable for perfusion fluids into a tissue cavity or body lumen which requires treatment. The catheter end portion includes a flexible elongate member having a proximal end, a distal end and at least one lumen extending there between. A portion of the distal end of the flexible elongate member is porous. Catheter end portions are fixably attachable to the distal end of a second catheter by methods known in the art, such as, by sonic welding, melting, glueing or by "snap fitting" where a male joint member fits into a female joint member. In one embodiment, the catheter end is non-inflatable.

The term "phototherapeutic" is intended to include photochemical, photoablative and photothermal processes which are therapeutic and/or prophylactic in a subject. Phototherapeutic treatment devices, e.g., lasers, have the advantage of using intense light energy which is rapidly attenuated to a non-destructive level outside of the targeted region. Linear diffusers distribute the intense light over long linear distributions. The terms "treat", "treatment" or "treating" are intended to include both prophylactic and/or therapeutic applications. The methods of the invention can be used to protect a subject from damage or injury caused by a disease, physical aberration, electrical aberration, or can be used therapeutically or prophylactically treat the subject after the onset of the disease or condition. Such treatment includes treatment with sufficient energy that the tissue no longer exhibits the previous disease or condition. Typically, energy is emitted from the device of the invention into the diseased tissue until the diseased tissue does not require further treatment. The tissue can be ablated, e.g., photoablated, coagulated, phototherapeutically modulated or otherwise altered by the emitted energy.

The terms "ablate" and "ablation" are well recognized in the art and are intended to include thermal coagulation and/or removal of tissues which are necrotic, damaged, or are aberrant in nature. Ablation also includes the desiccation of tissue by the application of heat. For example, an ablating energy, such as those described above, would be one that would cause the tissue to reach a temperature of between about 60-90° C. Ablation increases the physiological temperature of a tissue by energetic stimulation to a temperature which degrades or eradicates tissue, thereby prohibiting chaotic waves from propagating across the lesion. Ablation can be used as a therapeutic treatment, where diseased or otherwise unwanted tissue or cells exist, or as a preventative treatment to inhibit exigent physiological aberrations, e.g., atrial arrhythmias, e.g., fibrillations or flutters, growth of undesirable tissue or cells in a specific region of an organ or viscera. In order to obtain destruction of tissue exclusively by thermal effects, it is necessary for the energy to be able to reach a threshold of destruction referred to as the "thermal dose". This threshold is a function of temperature reached and of the duration of the application. Therefore, ablation, to some degree, is based on the rise of the local temperature of tissue. The term "coagulation" is well recognized in the art and is intended to mean the action whereby cells and/or body fluids within a treated tissue site are caused to become necrosed, thickened and/or lose the ability to conduct electrical activity, thereby resulting in a coherent mass by the methods of the invention. The method and apparatus of the invention permit selective, coagulation of a targeted tissue area and not blood or other body fluids which are found external, e.g., surrounding, to the target site.

The term "photochemical" is well recognized in the art and includes various energetic processes, including chemical reactions initiated by photons generated by an energy source. Typically photochemical processes are associated with laser, ultra-violet light, visible light or infrared light. Photochemical processes include the generation of radicals by photons colliding with tissue. The radical species are generated within cell tissue, often times causing oxidation of the cell contents; degradation or eradication occurs after the radical species are generated. In the method of the invention, photochemical reactions are selective for the targeted tissue area and not blood or other body fluids which are found external to the targeted treatment site.

Photochemical processes cause injury to cells and tissue either by mechanical lysis or by the generation of by-products such as free radicals, e.g., such as HO₂ ^», OH^'% HO^» and H₂O% which damage cell and/or tissue membrane. These reactive by-products can interact with the localized surrounding tissue area such that the tissue is cleansed of unwanted material. Photochemical processes can involve oxidation or radical polymerization of, for example, cell walls, extracellular matrix components, cell nuclei, etc. Such photochemical processes are generally induced by ultraviolet, laser and far infrared energy. Photochemical processes also include photoactivation of therapeutic agents which are either co-administered to the treatment site or previously administered locally or systemically.

The term "body fluids" is intended to encompass those naturally occurring physiological components produced by a subject to maintain stasis. These fluids typically include blood and its physiological components such as plasma, growth factors, platelets, lymphocytes, granulocytes, etc.

The terms "into" and "onto" are used interchangeably and are intended to include treatment of tissue by focusing phototherapeutic energy, e.g., ablative, coagulative, or photothermal, toward the afflicted area. In some instances the energy penetrates the tissue and in other instances the energy only superficially treats the surface of the tissue. An ordinary skilled artisan would understand what depths of penetration are required and those parameters which are dependent upon the application, tissue type, area to be treated and severity of condition. Accordingly, the amount of energy used to treat the afflicted area would be attenuated based upon the disease or condition being treated. "Interstitial cavity," as the term is used herein, encompasses interstices in a tissue or structure of a natural body structure, spaces and gaps existing between layers of tissue or existing within organs, and can include interstices within the interior of the ureter, bladder, intestines, stomach, esophagus, trachea, lung, blood vessel or other organ or body cavity, and will be further understood to include any surgically created interstice that defines an interior cavity surrounded by tissue.

The term "flexible elongate member" is well recognized in the art and is intended to refer to a hollow tube having at least one lumen. In general, a flexible elongate member is often termed a "catheter," a term which is well known in the art. The flexible elongate member has proximal and distal ends with at least one lumen, e.g., a longitudinal lumen, extending therebetween. The distal end can be open or closed as is known in the art. In one embodiment, the distal end of the flexible elongate member is open, thereby allowing an energy emitter, described infra, to protrude beyond the elongate member. In another embodiment, the distal portion of the elongate member is closed, thereby preventing an energy emitter from passing beyond the distal end of the elongate member.

Flexible elongate members, e.g., tubular catheters, can be formed from biocompatible materials known in the art such as cellulosic ethers, cellulosic esters, fluorinated polyethylene, phenolics, poly-4-methylpentene, polyacrylonitrile, polyamides, polyamideimides, polyacrylates, polymethacrylates, polybenzoxazole, polycarbonates, polycyanoarylethers, polyesters, polyestercarbonates, polyethers (polyethers block amide), polyetherketones, polyetherimide, polyetheretherketones, polyethersulfones, polyethylene, polypropylene, polyfluoroolefins, polyimides, polyolefins, polyoxadizoles, polyphenylene oxides, polyphenylene sulfides, polysulfones, polytetrafluoroethylene, polythioethers, polytriazoles, polyurethanes, polyvinyls, polyvinylidene fluoride, silicones, urea- formaldehye polymers, or copolymers or physical blends thereof.

Preferably, the materials used to construct the flexible elongate member or the catheter end portion can be "transparent" materials, such as fluoropolymers. Suitable transparent materials include polyethylene, nylon, polyurethanes and silicone containing polymers, e.g., silastic. Suitable fluoropolymers include, for example, fluorinated ethylene propylene (FEP), perfluoroalkoxy resin (PFA), polytetrafluoroethylene (PTFE), and ethylene-tetrafluoroethylene (ETFE). Typically the diameter of the flexible elongate member is between about 0.5 millimeters and about 2.5 millimeters, preferably between about 0.75 millimeters and about 2.0 millimeters. The diameter of at least one inner lumen of the flexible elongate member is between about 0.25 millimeters and about 1.5 millimeters, preferably between about 0.5 millimeters and about 1.0 millimeters. The length of the flexible elongate member varies with the intended application and in generally between about 1 meter and about 3 meters in length. For cardiac applications the flexible elongate member is between about 2 meters and about 3 meters long.

The term "catheter" as used herein is intended to encompass any hollow instrument capable of penetrating body tissue or interstitial cavities and providing a conduit for a fluid to an inflatable membrane with controlled permeability, including without limitation, venous and arterial conduits of various sizes and shapes, endoscopes, cystoscopes, culpascopes, colonscopes, trocars and laparoscope. Catheters of the present invention can be constructed with biocompatible materials known to those skilled in the art such as those listed supra, e.g., silastic, polyethylene, Teflon, polyurethanes, etc.

The term "biocompatible" is well recognized in the art and as used herein, means exhibition of essentially no cytotoxicity while in contact with body fluids or tissues. "Biocompatibility" also includes essentially no interactions with recognition proteins, e.g., naturally occurring antibodies, cell proteins, cells and other components of biological systems.

The term "transparent" is well recognized in the art and is intended to include those materials which transmit energy without substantial absorption or attenuation of the energy. Preferred energy transparent materials do not significantly impede (e.g., result in losses of over 20 percent of transmitted energy) the energy being transferred from an energy emitter to the targeted tissue or cell site. For phototherapy, suitable transparent materials can include fluoropolymers, for example, fluorinated ethylene propylene (FEP), perfluoroalkoxy resin (PFA), polytetrafluoroethylene (PTFE), and ethylene- tetrafluoroethylene (ETFE).

The term "fixedly attached" is intended to include those methods known in the art to attach a catheter end member or cap to the distal portion of a flexible elongate member. Various means are known to those skilled in the art for fixedly attaching external and internal members to a flexible elongate member. Such methods include thermal welding or glueing the two materials together to form a uniform seam which will withstand stresses placed upon the integral seam. In a preferred embodiment, the catheter end portion or a tip is "spot" welded, e.g., thermal, photochemical, sonically, e.g., ultrasound, or glued, at the proximal most portion of the catheter end or tip to the distal end of the flexible elongate member. In another preferred embodiment, the proximal end of the catheter end is affixed to the distal end of the elongate member which is itself a sealed, e.g., having a tip or a cap.

The terms "tip" or "cap" are well recognized in the art and are intended to include those devices which are used to seal the end of a luminal body. In one embodiment, the cap is non-metallic. In a preferred embodiment, the cap is non-metallic and porous, e.g., a polymeric membrane.

The term "catheter end portion" is intended to include a separate attachable, and in certain embodiments, detachable, catheter-like portion which is located proximate to the distal end of a catheter. The catheter end portion can be attached and integrally locked into place on the distal end of a catheter by methods known in the art, e.g., glueing, melting, ultrasonic welding, "snap on" fittings, male-female fittings, etc. The catheter end portion is porous and permits perfusion of a solution from a catheter about a targeted tissue area. This perfusion of solution into the targeted area diminishes the concentration of body fluids and/or blood surrounding the targeted area, thereby allowing optimal passage of energy, e.g., laser energy, through the solution and onto the targeted site.

The term "porous portion" is intended to include a distal end portion of a catheter which is integral with the flexible elongate member. This portion of a catheter permits perfusion of a solution from a catheter lumen through the porous portion into the targeted area. Perfusion of solution into the targeted area diminishes the concentration of body fluids and/or blood surrounding the targeted area, thereby allowing optimal passage of energy, e.g., laser energy, through the solution and into the targeted tissue site.

The term "porous" is well recognized in the art and is intended to include devices, such as catheters, which have discrete passageways, e.g., holes through the catheter body, which permit perfusion of solutions from a lumen. Alternatively, the pores are openings from a lumen to the outer surface of the catheter body. For example, pore size is generally between about 0.1 mm and about 1.0 mm, inclusive, preferably between about 0.2 mm and about 0.5 mm, inclusive, most preferably between about 0.3 mm and about 0.4 mm, inclusive. In one embodiment, the pore sizes found in the porous portion of a flexible elongate member of catheter end may randomly vary from between about 0.1 mm and about 1.0 mm, inclusive.

In one embodiment, pore sizes progressively vary from large to small, e.g., between about 0.2 mm and about 0.5 mm, inclusive as the pore progress from the distal tip backward along the flexible elongate member or catheter end. The gradation of pore sizes from smaller to larger along the longitudinal axis of the porous portion of the flexible elongate member or catheter end ensures that a pressurized solution will perfuse at a more uniform rate from the smallest pore sizes to the largest pores found at the distal portion of the apparatuses. Creating pores within or through the elongate flexible member can be accomplished by methods known in the art such as coring or laser hole cutting.

The porous portion of a flexible elongate member or catheter end can be a permeable matrix which does not have discrete passageways through the body but is considered an open cell foam or membrane, e.g., a matrix having a three-dimensional array of passageways which are interconnected and, generally, have a limiting pore size, e.g., between about 0.01 microns to about 50 microns.

The term "membrane" is well recognized in the art and is intended to include those polymeric materials which selectively facilitate the diffusion of small molecules in preference over larger molecules. The membrane can be selected so that molecules of a given molecular weight can pass through the polymeric matrix and molecules with larger molecular weights are retained and do not pass through the polymeric matrix. Preferably the membrane polymeric matrix is a hydrogel. Suitable materials for membranes useful in the present invention include biocompatible materials known in the art such as cellulosic ethers, cellulosic esters, fluorinated polyethylene, phenolics, poly-4-methylpentene, polyacrylonitrile, polyamides, polyamideimides, polyacrylates, polymethacrylates, polybenzoxazole, polycarbonates, polycyanoarylethers, polyesters, polyestercarbonates, polyethers, polyetherketones, polyetherimide, polyetheretherketones, polyethersulfones, polyethylene, polypropylene, polyfluoroolefins, polyimides, polyolefins, polyoxadizoles, polyphenylene oxides, polyphenylene sulfides, polysulfones, polytetrafluoroethylene, polythioethers, polytraizoles, polyurethanes, polyvinyls, polyvinylidene fluoride, silicones, urea- formaldehye polymers, or copolymers or physical blends thereof. Preferably, the material used to construct the porous portion, e.g., a membrane, is a "transparent" material, such as a fluoropolymer. Suitable fluoropolymers can include, for example, fluorinated ethylene propylene (FEP), perfluoroalkoxy resin (PFA), polytetrafluoroethylene (PTFE), and ethylene-tetrafluoroethylene (ETFE). Membranes are often associated with pore structure, e.g., an effective opening for passage of molecules. In one embodiment, membranes useful in this invention can be considered ultrafiltration membranes. In other embodiments, the pore sizes, in cases where there are distinct pore sizes, range from between about 0.01 microns to about 50 microns, preferably between about 0.02 microns to about 10 microns, more preferably between about 0.05 microns to about 5 microns, most preferably between about 0.1 microns to about 2 microns and between about 0.2 microns to about 2.5 microns. The ranges of pore sizes intermediate to those listed are also intended to be part of this invention, e.g., about 0.2 to about 25 microns, from about 2 to about 20 microns, from about 5 to about 30 microns and from about 0.1 to about 1.2 microns. For example, ranges of pore size values using a combination of any of the above values recited as upper and/or lower limits are intended to be included. In certain embodiments, the membrane is hydrophilic and can be a hydrogel.

The term "hydrophilic" is well recognized in the art and is intended to include those organic and/or inorganic functional groups which are more soluble in water than in nonpolar or hydrocarbon solvents, e.g., water wettable or dissolvable. Suitable examples of hydrophilic polymers include those which have alkoxides, such as phenols, hydroxybiphenyls, polyalkylene oxides (polyethers), polyamines, biphenyls, hydroxylated acrylates and methacrylates, e.g., hydroxylated alkyl acrylates and methacrylates, e.g., hydroxyethyl acrylates, hydroxyethyl methacrylates, hydroxypropylacrylates, hydroxypropylmethacrylates, polyalkylene oxide acrylates and methacrylates and sugar based derivatives, e.g., cellulosics.

The term "hydrogel" is well recognized in the art and is intended to include those polymers that swell with an aqueous solution, e.g., water, between two weight percent and 60 weight percent per volume of gel. Hydrogels are typically 80 to 90% water, preferably between about 50% and 98%, having indices of refraction close to 1.3. Mechanically, the hydrogels should be able to support a breaking tensile stress of between 40,000 and 60,000 dynes/cm². Chemically, the hydrogels should remain stable and not degrade in vivo. Hydrogel membranes utilized in the present invention can be crosslinked with known crosslinking agents.

The membrane polymeric matrix can be crosslinked via cross-linkers known in the art. For example, di, tri, or tetra acrylates or methacrylates can be used with those monomers listed above to form a crosslinked matrix. Typically, the membrane is lightly crosslinked, having a cross-link density of less than 25%, preferably less than 15%, more preferably less than 10%, still more preferably less than 5%, and most preferably less than 2%, e.g., between about 0.1% and 0.5%. The degrees of cross-link density intermediate to those listed are also intended to be part of this invention, e.g., between about 0.2% and about 0.75%, between about 0.8% to about 1.5% and between about 1.75%) to about

2.5%. For example, ranges of cross-link density using a combination of any of the above values recited as upper and/or lower limits are intended to be included.

The term "non-inflatable" is intended to mean that the porous portion of the flexible elongate member or catheter end do not inflate upon injection of a solution into the lumen. The porous portion of the flexible elongate member or catheter end are not, therefore, balloon like, and therefore, do not appreciably expand outwardly under pressure generated from injection of a solution, e.g., into a ballooned state.

The term "swellable" is well recognized in the art and is intended to mean that a membrane, e.g., a hydrogel, can swell in the x, y, and z, planes when a solution enters the pores and connecting channels between pores of a membrane. In effect, the membrane can act as a foam which holds the solution within the channels which are in communication between pores. As used herein, the term "foam" refers to a network of communicating microcompartments having solution interspersed within the walls of the polymeric microcompartments. Foams, which can be hydrogels, generally have microcompartments with the volume dimensions of x, y, and z wherein x = length, y = width, and z = height and are substantially equal. Typically, x, y, and z range from about 1 μ to about 300 μm, preferably from about 20 mm to about 200 mm, more preferably from about 40 mm to about 150 mm, and most preferably from about 50 mm to about 100 mm. Microcompartments have an average wall thickness of less than about 10 mm. The porous portion of a flexible elongate member or the porous catheter end are about 1 to about 10 cm in length, inclusive, preferably between about 2cm and about 8 cm, most preferably between about 3 cm and about 10 cm, inclusive. In one embodiment, the porous portion of the flexible elongate member is a second lumen located within a first lumen. The second lumen provides a chamber by which a solution can be injected through the lumen to the porous portion. The second lumen can be closed and can have pores, as described supra, e.g., distinct pores or membrane like pores, which open to the exterior of the outer flexible elongate member suitable for irrigating a targeted tissue site. Alternatively, the second lumen can have an open end, to which is attached a catheter end, e.g., a membrane, or integrally forms a membrane, which forms a "sponge" at the end of the lumen, suitable for irrigating the targeted tissue site. In a preferred embodiment, the porous portion, e.g., the membrane, has an interior lumen which allows an energy emitter to be slidably positioned within the lumen. The term "control handle" is are recognized and is intended to include various means to manipulate the apparatus of the invention, including at least the flexible elongate member, guidewires if present, and the energy emitter, described infra. Various control handles useful with the present invention are commercially available, such as those manufactured by Cordis Webster, Inc. 4750 Littlejohn St , Baldwin Park, CA, 91706. When used, the control handle applies tension, e.g., stress, to the proximate end of a guidewire, thereby causing the distal end of the guidewire to bend, distort or deform. As a consequence of this action, the flexible elongate member to which the guidewire is attached, also bends, distorts or deforms in the same plane as the guidewire.

The term "energy emitter" is intended to include those apparatus which conduct energy in the form of an electrical current, radio-frequency, ultrasound, microwave radiation, ultraviolet light, infrared radiation, or an optical wave guide such as a wave guide for coherent light, e.g., laser light. Typically, the energy transmitted is in the range between about 200 nanometers and about 10.5 micrometers. In a preferred embodiment, the energy emitter is a diffusing tip. A preferred energy is coherent light, e.g., laser light, in the range between about 200 nm and about 2.4 μm, preferably between about 600 nm and about 1.4 μm, more preferably between about 600 nm and about 1064 nm, most preferably between about 805 nm and about 940 nm. A most preferred range is between about 900 and 950 nm, preferably between about 910 and 920 nm, with a most preferred wavelength of about 915 nm. Another preferred range is between about 800 nm and about 810 nm. Suitable lasers include diode lasers, Yag:Nd lasers, diode pumped solid state lasers, excimer lasers, and AlGaAs diode arrays. A particularly preferred AlGaAs diode array, manufactured by Optopower, Tucson, Arizona, produces a wavelength of 915 nm. Typically the energy emitter emits between about 2 to about 10 watts/cm of length, preferably between about 4 to about 6 watts/cm, most preferably about 4 watts/cm. In one embodiment, the energy emitter can extend beyond the distal end of the flexible elongate member and into a lumen created by a porous portion of a flexible elongate member or a catheter end which is porous, e.g., a membrane.

The energy emitter transmits the energy from an energy source which is in communication with the proximal end of the energy emitter. Suitable energy sources are known in the art and produce the above-mentioned types of energy. The energy emitter is positioned within lumen formed by a flexible elongate member (described supra). The energy emitter can be slidably controlled within the lumen such that positioning of the energy emitter at the porous portion of the flexible elongate member is readily achieved.

The energy emitter can have many forms known to those skilled in the art and can include a light diffuser or other appropriate configurations. Exemplary tips are described in U.S. Patents 5,042,980, 5,207,669, 5,253,312, 5,269,777, and those diffusion tips described in "Phototherapeutic Apparatus" by Edward L. Sinofsky, Lincoln S. Baxter and Norman Farr, and PCT Application No. PCT/US95/11246, International Publication No.

WO 96/07451, published March 14, 1996, the teachings of all are incorporated herein by reference. A preferred tip is the diffusing laser tip available from Cardiofocus, Inc., West Yarmouth, MA 02673. The end of the tip can also be coated or coupled with an energy or light reflecting or deflecting material in order to prevent forward propagation of ablating energy.

The term "subject" is intended to include mammals susceptible to diseases, including one or more disease related symptoms. Examples of such subjects include humans, dogs, cats, pigs, cows, horses, rats and mice.

The term "tissue" is well recognized in the art and is intended to include both organs and interstitial materials, e.g., mesentery, liver, kidney, heart, lung, brain, tendon and muscle.

The language "undesirable cell proliferation" is intended to include abnormal growth of cells which can be detrimental to a subject's physiological well being. Effects of undesirable cell proliferation can include the release of toxins into the subject, fever, gastritis, inflammation, nausea, weakness, coma, headache, water retention, weight gain or loss, immunodeficiency, death, etc. The undesired cells which proliferate can include cells which are either benign or malignant. Examples of undesirable cell proliferation include bacterial cell proliferation and aberrant cell division and/or proliferation of foreign cells, such as in cancer cells. The terms "aberrant cell" or "aberrant tissues" as used herein, is well recognized in the art and is intended to include aberrant cell division and/or proliferation where cells are generated in excess of what is considered typical in physiologically similar environment, such as in cancers. The language "control of undesirable cell proliferation" or "controlling undesirable cell proliferation" is intended to include changes in growth or replication of undesired cells or eradication of undesired cells, such as bacteria, cancer, or those cells associated with abnormal physiological activity. The language includes preventing survival or inhibiting continued growth and replication of an undesired cell. In one preferred embodiment, the control of the undesired cell is such that an undesired cell is eradicated. In another preferred embodiment, the control is selective such that a particular targeted undesired cell is controlled while other cells, which are not detrimental to the mammal, are allowed to remain substantially uncontrolled or substantially unaffected, e.g., lymphocytes, red blood cells, white blood cells, platelets, growth factors, etc.

The term "cancer" is well recognized in the art and is intended to include undesirable cell proliferation and/or aberrant cell growth, e.g., proliferation.

The term "modulate" includes effect(s) targeted tissue(s) that prevent or inhibit growth of diseased tissue, which may ultimately affect the physiological well being of the subject, e.g., in the context of the therapeutic or prophylactic methods of the invention.

The term "modify" is intended to encompass those changes the targeted tissue site, e.g., the surface, that cause the tissue to no longer have undesired properties. For example, treatment of the anterior wall of the right atrium by the present invention changes the path of electrical conduction after photonic treatment. The result is a conduction block which redirects conduction through the tissue and prevents the conduction from traveling across the atrial wall as it did prior to treatment.

The terms " solution" and/or "flushing solution" are intended to include those solutions, e.g., aqueous solutions, which can be administered to a subject through a device of the present invention without subsequent adverse effects. In particular, the solution should not significantly degrade the strength, quality, or wavelength of energy emitted, e.g., laser energy, from the energy emitter. In general, the solution should be a pharmaceutically acceptable carrier or vehicle. The phrase "pharmaceutically acceptable carrier" as used herein means a pharmaceutically acceptable material such as a liquid, diluent, or solvent, such that it can performs its intended function, e.g., flushes the tissue site to be treated. The solution can also include pharmaceutical agents, including drugs and photoactivatable compositions. In certain embodiments, the solution can contain radiopaque contrast agents. In still another aspect, the present invention is drawn to methods for phototherapeutically treating, e.g., ablating, coagulating, and or phototherapeutically modulating, a target tissue. The methods include introducing a flexible elongate member into a predetermined tissue site. The flexible elongate member has a proximal end, a distal end and at least one lumen extending therebetween. A portion of the distal end of the flexible elongate member is porous, such that the porous portion is positioned proximate to the tissue site. A solution is expelled through the porous portion, thereby diluting or eliminating body fluid(s) and/or blood about the tissue site. An energy emitter can be slidably positioned through the lumen proximate to the tissue site and energy is transmitted to the porous portion of the distal end of the elongate member through the energy emitter. Advantageously, the target tissue is phototherapeutically treated without damaging the surrounding tissue.

In yet another aspect, the present invention is drawn to methods for phototherapeutically treating, e.g., ablating, coagulating, and/or phototherapeutically modifying, a trabecular surface. The methods include introducing a flexible elongate member into the right atrium. The flexible elongate member has a proximal end, a distal end and at least one lumen extending therebetween. A portion of the distal end of the flexible elongate member is porous, such that the porous portion is positioned proximate to the trabecular surface of the right or left atrium. A solution is passed via the lumen through the porous portion, thereby diluting or eliminating body fluid(s) and/or blood about the trabecular surface. An energy emitter can be slidably positioned through the lumen proximate to the trabecular surface and energy is transmitted to the porous portion of the distal end of the elongate member through the energy emitter. Alternatively, the energy emitter can be fixed to the distal end of the instrument or slidably disposed in a separate lumen. In one application of the invention, the trabecular surface can be the internal surface of an atrial chamber which is phototherapeutically treated without damaging the surrounding tissue. Such treatment can provide one or more lesions, preferably linear lesions, on the surface of the atrial wall which impede generation and/or propagation of aberrant electrical wavefronts which are causative or associated with heart conditions, e.g., arrhythmia, atrial fibrillation, atrial flutter.

In still another aspect, the present invention pertains to methods for treating or preventing atrial fibrillation. The methods include introduction of a flexible elongate member proximate the atrial tissue. The flexible elongate member includes a proximal end, a distal end and a lumen extending therebetween. A portion of the distal end of the flexible elongate member is porous, such that said porous portion is proximate to a surface of atrial tissue. A solution is injected through the porous portion, thereby diluting or eliminating any body fluid about the atrial surface. This dilution enhances the light's penetration through the blood or body fluid(s). An energy emitter is positioned in the lumen proximate to the atrial surface and energy is emitted energy through the porous portion of the flexible elongate member onto the atrial surface without damaging surrounding tissue.

Atrial fibrillation and atrial flutter are abnormalities in the rhythm or rate of the heart beat. For an adult at rest, the heart normally beats between 60 and 80 beats per minute, but when atrial fibrillation occurs, the atria may beat irregularly and very rapidly between 350 and 600 times per minute. This causes the ventricles to beat irregularly in response as they try to keep up with the atria. Atrial flutter is similar to atrial fibrillation. The atrial contractions are less rapid, however, usually between 200 to 400 beats per minute, and are regular. Atrial flutter is often associated with a heart attack or may occur after heart or lung surgery. Atrial fibrillation often results from a myriad of heart conditions such as angina, tachycardia, heart attack, heart valve problems, and even high blood pressure. All of these conditions can cause stretching and scarring of the atria that interfere with the heart conduction system. The heart muscle can be weakened if episodes lasting several months or longer (with rapid heart rates) occur. Briefer episodes only cause problems if the heart rate is very fast or if the patient has a serious heart problem in addition to the atrial fibrillation.

FIGS. 1, 2 and 3 illustrate an apparatus of the invention 10. In FIG. 1, apparatus 10 includes a flexible elongate member 12 having a porous portion 14, pores 16, lumen 18, and an energy emitter 22 (with diffusion tip, not shown) which can be slidably positioned within lumen 18 and, optionally, a distal end cap 20 and , optionally, a reflective material 30. In one embodiment, the energy emitter 22 is loosely fit into lumen 18 to permit a solution in lumen 18 to pass beyond the front portion of energy emitter 22. In FIG. 2, catheter end 24 is affixed to flexible elongate member 22 at attachment site 26. Optionally, catheter end 24 can be detached from attachment site 26. Catheter end 24 includes a porous portion having pores 16 from which a solution can be diffused or otherwise expelled from lumen 18. FIG. 3 is a cross-section view of flexible elongate member 12 taken along lines 3-3 of FIGS. 1 and 2, depicting pores 16 which extend from lumen 18 through porous portion 14/catheter end 24.

The term "reflective material" is intended to encompass those materials which reflect energy, such as light, e.g., laser, ultraviolet, visible, or infrared light. Suitable materials are known in the art and include metal foils useful in the art, preferably gold.

Typically the reflective material has a thickness between about 0.05 mm and about 0.1 mm, inclusive. The reflectance material helps to eliminate the illumination of blood, decreases the power needed to penetrate through body fluid(s), and confines the scattered light to the affected tissue. In one embodiment, reflective material 30 encircles approximately one half of the energy conductor 22, which can include a diffusive tip, and reflects and concentrates the energy toward the treatment site. Typically the reflective material is configured into a 180 degree tube which can be slidably positioned with the energy conductor 22 or fixedly attached to flexible elongate member 12. Reflectance fiber 32 , described infra, is used to monitor the degree of treatment by the methods described herein.

FIGS. 4, 5 and 6 illustrate another aspect of apparatus 10. In FIG. 4, flexible elongate member 12 includes a porous portion 14, first lumen 18, second lumen 28, e.g., a second outer catheter or a hollowed wall of flexible elongate member 12, which includes pores 16 and an energy emitter 22 (including a diffusive tip, e.g., a light diffuser not shown) which can be slidably positioned within lumen 18 and, optionally, a distal end cap 20 and reflective material 30. In one embodiment, energy emitter 22 is loosely fit into lumen 18 to permit positioning. In FIG. 5, catheter end 24 is affixed to flexible elongate member 22 at attachment site 26. Catheter end 24 includes a porous portion having pores 16 from which a solution can be diffused or otherwise expelled from second lumen 28. FIG. 6 is a cross-section view of flexible elongate member 12 taken along lines 6-6 of FIGS. 4 and 5, depicting pores 16 which extend from second lumen 28 through porous portion 14/catheter end 24.

FIG. 7 is a depiction of a preferred embodiment of the invention. In FIG. 7, flexible elongate member 12 includes a porous portion 14, first lumen 18, second lumen

28, e.g., a second outer catheter or a hollowed wall of flexible elongate member 12, which includes pores 16 and an energy emitter 22 (including a diffusive tip, e.g., a light diffuser 34) which can be slidably positioned within lumen 18 and a distal end cap 20 and reflective material 30.

The devices described in FIGS. 1-7 can be used for treating, e.g., ablating, coagulating or phototreating, endocardial surfaces which promote arrhythmias. For example, right heart catheterization can be performed by inserting an apparatus of the invention 10 into the femoral vein. Flexible elongate member 12 having porous portion 14 or detachably affixed catheter end 24 is guided through the inferior vena cava, and into the right atrium, and if required, it is guided into the left atrium. Left atrial catheterization can be performed by transseptal puncture, then inserting flexible elongate member 12 having deflection member 20. Flexible elongate member 12 is guided through the iliac artery, the aorta, through the aortic valve and into the left ventricle. Once porous portion 14 or catheter end 24 is proximate to the tissue ablation site, a solution can be injected through lumen 18 or 28 to flush or perfuse the treatment site, thereby diluting or removing blood and/or body fluids. In either example, energy emitter 22 is pushed through flexible member 12 via lumen 18 to a position proximate to the tissue ablation site and an energy, e.g., laser energy, emitted through porous portion 14 or catheter end 24 and solution to treat the targeted tissue. Preferably, the composition of porous portion 14 or catheter end 24 is transparent to the energy emitted by energy emitter 22. In the present invention, reflective feedback is used to monitor the state of coagulation, ablation and/or phototherapeutic processes of the treatment site so as to allow an optimal dose by either manipulation of the energy level or exposure time, or by controlling the sweep of energy across an exposure path.

Reflectance changes can also be employed by a control means in the present invention to adjust or terminate laser operation.

In another aspect of the invention, a real-time display means can be incorporated into a surgical microscope or goggles worn by a clinician during the procedure to provide a visual display of the state of tissue coagulation simultaneously with the viewing of the surgical site. The display can reveal reflectance values at one or more specific wavelengths (preferably, chosen for their sensitivity to the onset and optimal state of tissue modification), as well as display a warning of the onset of tissue carbonization. In one method, according to the invention, application of laser to a biological structure^ ) while the reflectance of light from the irradiated site is monitored. Changes in scattering due to coagulation, ablation, phototherapetuic effects or crosslinking of the tissue will cause a reflectance change. In addition, dehydration due to laser exposure also affects the site's reflection. The reflectance can be monitored in real-time to determine the optimal exposure duration or aid as visual feedback in the timing used in sweeping the energy across the treatment site during the procedure.

In FIG. 8, a schematic block diagram of a laser tissue treatment system 36 is shown, including a laser 38, power supply 40, controller 42 and reflectance monitor 44. The system further includes optical apparatus 10, and, optionally, illumination source 46, display 48 and/or tuner 50. In use, the output of laser 58 is delivered, preferably via optical apparatus 10, to treatment site 52 to phototherapeutically treat selected tissue. As the laser beam irradiates treatment 52 the biological tissue of the site is coagulated, ablated and/or phototherapeutically treated. The degree of treatment is determined by the reflectance monitor 44, which provides electrical signals to controller 42 in order to control the procedure. The reflectance monitor 44 receives light reflected by the site from a broadband or white light illumination source 46 via fiber 47 and/or from laser 48. In addition to controlling the laser operation automatically, the reflectance monitor 44 and/or controller 42 can also provide signals to a display 48 to provide visual and/or audio feedback to the clinical user. Optional, tuner 50 can also be employed by the user (or automatically controlled by controller 42) to adjust the wavelength of the annealing radiation beam.

FIG. 9 is a more detailed schematic diagram of a reflectance monitor 44, including a coupling port 54 for coupling with one or more fibers 56 to receive reflectance signals. A preferred reflectance fiber is a 100 micron diameter silica pyrocoat fiber from Spectran (Spectran, Connecticut, part number CF04406-11). The reflectance monitor 44 can further include a focusing lens 58 and first and second beam splitting elements 60 and 62, which serve to divide the reflected light into 3 (or more) different beams for processing. As shown in FIG. 9, a first beam is transmitted to a first optical filter 64 to detector 66 (providing, for example, measurement of reflected light at wavelengths shorter than 0.7 micrometers). A second portion of the reflected light signal is transmitted by beam splitter 62 through a second optical filter 68 to detector 70 (e.g., providing measurement of light at wavelengths shorter than 1.1 micrometers). Finally, a third portion of the reflected light is transmitted to photodetector 72 (e.g., for measurement of reflected light at wavelengths greater than 1.6 micrometers). Each of the detector elements 66, 70 and 72 generate electrical signals in response to the intensity of light at particular wavelengths.

The detector elements 66, 70 and 72 preferably include synchronous demodulation circuitry and are used in conjunction with a modulated illumination source to suppress any artifacts caused by stray light or the ambient environment. (It should be apparent that other optical arrangements can be employed to obtain multiple wavelength analysis, including the use, for example, of dichroic elements, either as beam splitters or in conjunction with such beam splitters, to effectively pass particular wavelengths to specific detector elements. It should also be apparent that more than three discreet wavelengths can be measured, depending upon the particular application.) The signals from the detector elements can then be transmitted to a controller and/or a display element (as shown in FIG. 8).

In the controller, signals from the reflectance monitor are analyzed to determine the degree of coagulation, ablation and/or phototherapeutic effect(s) which is occurring in the biological tissue exposed to the laser radiation. Typically, such treatment is performed for 100 seconds or less. Such analysis can generate control signals which will progressively reduce the laser output energy over time as a particular site experiences cumulative exposure. The control signals can further provide for an automatic shut-off of the laser when the optimal state of treatment has been exceeded and/or the onset of carbonization is occurring.

In use, the apparatus of the present invention can be employed to analyze the degree of treatment by comparing the reflectance ratios of a site at two or more wavelengths. Preferably, intensity readings for three or more wavelength ranges are employed in order to accurately assess the degree of treatment and to ensure that the optimal state is not exceeded. The particular wavelengths to be monitored will, of course, vary with the particular tissue undergoing treatment. Although the tissue type (e.g., blood-containing tissue or that which is relatively blood- free) will vary, the general principles of the invention, as disclosed herein, can be readily applied by those skilled in the art to diverse procedures in which the phototherapeutic treatment of biological materials is desired. Those skilled in the art will know, or be able to ascertain, using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims. All publications and references cited herein including those in the background section are expressly incorporated herein by reference in their entirety.

What is claimed is:

Claims

1. An apparatus for effecting phototherapeutic processes in tissue comprising: a flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending therebetween, wherein a portion of said distal end of said flexible elongate member is porous; and an energy emitter slidably extending within said first lumen for transmitting energy to said distal end of said elongate member, said energy emitter having a proximal end and a distal end.

2. The apparatus of claim 1 , wherein said porous portion includes pores which extend from said first lumen through said porous portion.

3. The apparatus of claim 2, wherein said size of said pores increases from a proximal portion to a distal portion.

4. The apparatus of claim 3, wherein said pore size increases from said proximal portion from about 0.1 mm to about 0.5 mm at said distal portion.

5. The apparatus of claim 1 , wherein said flexible elongate member wall forms a second lumen and said porous portion includes pores which open from second lumen.

6. The apparatus of claim 5, wherein said porosity of said porous portion increases from a proximal portion to a distal portion.

7. The apparatus of claim 6, wherein said pore size increases from said proximal portion from about 0.1 mm to about 0.5 mm at said distal portion.

8. The apparatus of claim 1, wherein said flexible elongate member is transparent.

9. The apparatus of claim 1 , wherein said flexible elongate member is curved.

10. The apparatus of claim 1 , wherein said distal end of said flexible elongate member has a curved distal end.

11. The apparatus of claim 1 , wherein said flexible elongate member includes a reflective element on one side.

12. A detachable catheter end portion suitable for perfusion fluids, comprising a flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending there between, wherein a portion of said distal end of said flexible elongate member is porous.

13. The apparatus of claim 12, wherein said porous portion includes pores which extend from said first lumen through said porous portion.

14. The apparatus of claim 13 , wherein said porosity of said porous portion increases from a proximal portion to a distal portion.

15. The apparatus of claim 14, wherein said pore size increases from said proximal portion from about 0.1 mm to about 0.5 mm at said distal portion.

16. The apparatus of claim 12, wherein said flexible elongate member wall forms a second lumen and said porous portion includes pores which open from second lumen.

17. The apparatus of claim 16, wherein said pore size of said porous portion increases from a proximal portion to a distal portion.

18. The apparatus of claim 17, wherein said pore size increases from said proximal portion from about 0.1 mm to about 0.5 mm at said distal portion.

19. The apparatus of claim 12, wherein said flexible elongate member is transparent.

20. The apparatus of claim 12, wherein said flexible elongate member is curved.

21. The apparatus of claim 12, wherein said distal end of said flexible elongate member has a curved distal end.

22. The apparatus of claim 12, wherein said flexible elongate member includes a reflective element on one side.

23. A method for treating a target tissue, comprising the steps of: introducing a flexible elongate member into a predetermined tissue site, said flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending there between, wherein a portion of said distal end of said flexible elongate member is porous, such that said porous portion is proximate to said tissue site; injecting a solution through said porous portion, thereby diluting body fluid about said tissue site; positioning an energy emitter in said lumen proximate to said tissue site; and transmitting energy from said energy emitter through said porous portion of said flexible elongate member onto said target tissue without damaging surrounding tissue.

24. The method of claim 23, wherein said body fluid is blood.

25. The method of claim 23, wherein said transmission of energy is between about 600 and 1064 nm.

26. The method of claim 23, wherein said transmission of energy is between about 900 and 920 nm.

27. The method of claim 23, wherein said porous portion of said flexible member is transparent.

28. The method of claim 23, further comprising the step of slidably positioning said energy emitter through said first lumen proximate to said tissue site.

29. A method for treating a trabecular surface, comprising the steps of: introducing a flexible elongate member into a right or left atrium, said flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending there between, wherein a portion of said distal end of said flexible elongate member is porous, such that said porous portion is proximate to said trabecular surface of said atrium; injecting a solution through said porous portion, thereby diluting body fluid about said trabecular surface; positioning an energy emitter in said lumen proximate to said trabecular surface; and transmitting energy from said energy emitter through said porous portion of said flexible elongate member onto said trabecular surface without damaging surrounding tissue.

30. The method of claim 29, wherein said body fluid is blood.

31. The method of claim 29, wherein said transmission of energy is between about 600 and 1064 nm.

32. The method of claim 29, wherein said transmission of energy is between about 900 and 920 nm.

33. The method of claim 29 wherein said porous portion of said flexible member is transparent.

34. The method of claim 29, further comprising the step of slidably positioning said energy emitter through said first lumen proximate to said trabecular surface.

35. A method for treating or preventing atrial fibrillation, comprising the steps of: introducing a flexible elongate member proximate to atrial tissue, said flexible elongate member having a proximal end, a distal end and a lumen extending there between, wherein a portion of said distal end of said flexible elongate member is porous, such that said porous portion is proximate to a surface of said atrial tissue; injecting a solution through said porous portion, thereby diluting body fluid about said atrial surface; positioning an energy emitter in said lumen proximate to said atrial surface; and transmitting energy from said energy emitter through said porous portion of said flexible elongate member onto said atrial surface without damaging surrounding tissue.

36. An apparatus for effecting phototherapeutic processes in tissue comprising: a flexible elongate member having a proximal end, a distal end and a longitudinal first lumen extending therebetween, wherein a portion of said distal end of said flexible elongate member is porous; an energy emitter slidably extending within said first lumen for transmitting energy to said distal end of said elongate member, said energy emitter having a proximal end and a distal end; an energy source in communication with said proximal end of said energy emitter effective to transmit laser energy through said conductor; a reflectance sensor for measuring intensity of light reflected from said tissue while illuminating said tissue; a monitor connected to said reflectance sensor for monitoring changes in the intensity of light reflected from said tissue; an analyzer connected to said monitor for determining the degree of therapeutic treatment based upon said monitored changes in said tissue; and a controller connected to said analyzer and laser for controlling the output of said laser in response to said reflected light from said treated tissue.

37. A method for treating or preventing atrial fibrillation, comprising the steps of: introducing a flexible elongate member proximate to atrial tissue, said flexible elongate member having a proximal end, a distal end and a lumen extending there between, wherein a portion of said distal end of said flexible elongate member is porous, such that said porous portion is proximate to a surface of said atrial tissue; injecting a solution through said porous portion, thereby diluting any body fluid about said atrial surface; positioning an energy emitter in said lumen proximate to said atrial surface; and transmitting laser energy from said energy emitter through said porous portion of said flexible elongate member onto said atrial surface; measuring the intensity of light reflected from said target tissue; and controlling the energy applied to said site in response to monitored changes in the intensity of said light reflected from said target tissue, thereby treating or preventing atrial fibrillation.