Abstract:
A method and device for perfusing an organ system is provided. The device may be further described as a catheter or cannula with an expandable flow control member positioned of the distal portion of the catheter shaft. The flow control member has a porous portion, and at least one impermeable portion, which prevent fluid from flowing out the ends of the flow control member. The flow control member is further characterized as having an interior chamber that is in fluid communication with a perfusion lumen that extends along the length of the catheter shaft and is in fluid communication with an external perfusion pump. The perfusion lumen is configured for providing flow to the interior of the flow control member, to create radial expansion thereof and to provide adequate flow to the arch vessels through said porous portion to sustain the metabolic demands of the brain.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to a catheter or cannula system that facilitates cardiopulmonary surgeries and enables prolonged circulatory support of the heart. More specifically, the invention relates to an aortic catheter for segmenting and selectively perfusing the aorta during cardiopulmonary bypass.  
         BACKGROUND OF THE INVENTION  
         [0002]    Heart surgery has generally required major open chest surgical procedures that put the patient at risk. Relatively high mortality rates and complications result from such invasive surgeries. Further, the surgeries require extensive hospitalization and recuperation time. Surgical methods to correct heart problems are desirable which do not require open chest approaches. Some surgical techniques have been described for particular applications employing an intra-aortic catheter introduced into the vascular system of the patient.  
           [0003]    Recent advances in the field of minimally invasive cardiac surgery have included the development of aortic catheters and methods for inducing cardioplegic arrest without the necessity of opening the patient&#39;s chest with a stemotomy or other major thoracotomy. For example, U.S. Pat. No. Re 35,352 to Peters describes a single-balloon catheter for occluding a patient&#39;s ascending aorta and a method for inducing cardioplegic arrest. A perfusion lumen or a contralateral arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. U.S. Pat. No. 5,584,803 to Stevens et al. describes a single balloon catheter for inducing cardioplegic arrest and a system for providing cardiopulmonary support during closed chest cardiac surgery. A coaxial arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. The occlusion balloon of these catheters must be very carefully placed in the ascending aorta between the coronary arteries and the arch vessels, therefore the position of the catheter must be continuously monitored to avoid complications.  
           [0004]    One difficulty encountered with prior art aortic catheters is the tendency of the single balloon catheters to migrate or drift in the direction of the pressure gradient within the aorta. Specifically, during infusion of cardioplegia, the balloon catheter will tend to drift downstream away from the heart and toward the aortic arch and, when the cardiopulmonary bypass pump is engaged during the procedure, the balloon catheter will tend to drift upstream in the opposite direction toward the heart into the aortic root. This migration can be problematic if the balloon drifts downstream far enough to occlude one or more of the arch vessels, or upstream enough to occlude the coronary arteries, or to pass through the aortic valve into the ventricle.  
           [0005]    PCT patent application WO 9721462 by Fan et al. attempts to overcome this problem with a balloon catheter having high friction areas on the outer surface of the balloon. A problem with this single balloon approach is that a relatively large balloon is needed to create enough friction to avoid migration of the inflated balloon. The larger the balloon is, the more carefully it must be placed in the ascending aorta to avoid occluding the coronary arteries or the arch vessels and the less margin of error there is should any balloon migration occur.  
           [0006]    Furthermore, what is needed are medical instruments and cannula/catheters for compartmentalizing and selectively perfusing the cerebral circulation with antegrade flow. Such mechanisms are necessary to minimize complications of a vast array that are related to proper management of blood flow in the body. Selective perfusion can be used to prioritize the flow of oxygenated blood or other protective fluids to the various organ systems, therefore achieving optimal preservation of all organ systems within the body.  
           [0007]    Furthermore, what is needed is a peripheral access catheter configuration that is more resistant than prior apparatus to migration due to pressure gradients within the patient&#39;s aorta.  
           [0008]    The following patents, and all other patents referred to herein, are hereby incorporated by reference in their entirety: U.S. Pat. Nos. 5,308,320, 5,383,854, 5,820,93 and 5,906,588 by Safar et al.; U.S. patent application Ser. No. 08/909,293, filed Aug. 11, 1997, by Safar et al.; U.S. patent application Ser. No. 09/152,589, filed Sep. 11, 1998, by Safar et al.; U.S. Pat. No. 5,738,649, by John A. Macoviak; U.S. patent application Ser. No. 09/060,412 filed Apr. 14, 1998 by Macoviak; U.S. Pat. Nos. 5,833,671, 5,827,237 by John A. Macoviak and Michael Ross; U.S. patent application Ser. No. 08/665,635, filed Jun. 17, 1996, by John A. Macoviak and Michael Ross; and U.S. patent application Ser. No. 09/205,753, filed Dec. 8, 1998, by Bresnahan et al.  
         SUMMARY OF THE INVENTION  
         [0009]    Accordingly, the invention provides a catheter or cannula having a flow control member positioned near the distal end of the catheter for occluding a first body lumen at a point where a second body lumen branches from the first lumen, and for perfusing the branch lumen. The invention will be described more specifically herein relating to an aortic catheter or cannula having an occlusion member positioned in the aortic arch, having a length sufficient to cover the ostia of the arch vessels. The flow control member is intended to fulfill at least one and preferably all four of the following functions: (1) occluding the aorta at the aortic arch, (2) selectively perfusing one or more of the coronary arteries, the arch vessels, or the descending aorta with a selected fluid, (3) providing filtered perfusion to one or more of the coronary arteries, the arch vessels, or the descending aorta, and (4) resisting migration of the distal flow control member and the cannula.  
           [0010]    The primary flow control member may be formed in a variety of configurations, but will include a primary flow control member positioned in the aortic lumen, having a length sufficient to cover the ostia of the arch vessels. The flow control member may comprise one or more inflatable balloons or one or more selectively deployable external catheter valves, or a combination of balloons and valves. In embodiments where the primary flow control member is a single inflatable balloon, the flow control member will have at least one permeable or mesh portion. The balloons used, whether porous or nonporous, may be elastic so that they stretch in proportion to the inflation pressure, or may be flaccid or sack-like so that they inflate at low pressure and reach their design diameter quickly. The sack-like balloons may be relatively non-compliant at their design diameter or they may be compliant, exhibiting elastic behavior after initial inflation, e.g. to closely fit the aortic lumen size and curvature.  
           [0011]    The catheter may further include one or more auxiliary flow control members located upstream or downstream from the primary flow control member to further segment the patient&#39;s circulatory system for selective perfusion to different organ systems or to assist in anchoring the catheter in a desired position. Usable auxiliary flow control members include, but are not limited to, expandable or inflatable members such as inflatable balloons and valves. Examples of various valves may include collapsible/expandable valves including retrograde valves, antegrade valves, and various central flow and peripheral flow valves. In addition, a combination of valves and inflatable members may be used as appropriate for a given procedure. In some embodiments, the catheter body can include one or more antegrade and retrograde valves, as well as one or more inflatable balloons. Inflatable balloons and collapsible/deployable valves have been previously incorporated by reference herein and any desirable or practical inflatable balloon or deployable valve may be used. Inflatable balloons typically include an interior chamber that is in fluid communication with an inflation lumen extending within the catheter shaft from a location from within the respective flow control member to a location in the proximal portion, which is adapted to extend out of the patient.  
           [0012]    Preferably, the flow control member, and any auxiliary flow control members, or anchoring members, if present, are mounted on an elongated catheter shaft. In a preferred embodiment, the catheter shaft includes at least one lumen for inflating or otherwise deploying the primary flow control member and for perfusion of the arch vessels with oxygenated blood or other fluids, a lumen for corporeal perfusion, and a guidewire lumen. In alternate embodiments, lumens may be included for deploying the auxiliary flow control members, and for measuring the pressure at desired locations within the aorta. The catheter may be configured for retrograde deployment via a peripheral artery, such as the femoral artery, or it may be configured for antegrade deployment via an aortotomy incision or direct puncture in the ascending aorta.  
           [0013]    In some embodiments of the invention, filtration may be an important feature. To capture embolic material without unduly disrupting blood flow, the porous section or sections must have an appropriate combination of characteristics including effective filter surface area and pore size; the correct combination depending on a number of factors including fluid pressure. For filters comprised of a mesh, the thread diameter is another important characteristic to consider. Typically, the flow rates required in the arch vessels total between 0.5 and 1.5 L/min depending on a variety of factors including the size of the patient and the temperature of the perfusate. Pore size is preferably 500 μm or less, more preferably 200 μm or less, and most preferably 50 μm or less, but larger than at least a red blood cell, although larger pore sizes may be required in some embodiments.  
           [0014]    Methods according to the present invention are described using the aortic catheter for occluding and compartmentalizing or partitioning the patient&#39;s aortic lumen and for performing selective filtered aortic perfusion. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side view of a shaft portion of a first embodiment of the aortic catheter of the present invention having a single-balloon flow control member in the unexpanded state.  
         [0016]    [0016]FIG. 2 is a magnified lateral cross section of the aortic catheter shaft of FIG. 1 taken along line  2 — 2 .  
         [0017]    [0017]FIG. 3 is a side view of the flow control member of the aortic catheter of FIG. 1 showing a single-balloon flow control member in a deployed or expanded state.  
         [0018]    [0018]FIG. 4 is a side view of the aortic catheter of FIG. 1 configured for retrograde introduction into a patient&#39;s femoral artery and illustrating the manifold connections to the proximal end of the aortic catheter.  
         [0019]    [0019]FIG. 5 is a side view of the aortic catheter of FIG. 1 deployed or expanded in an aorta.  
         [0020]    [0020]FIG. 6 is a side view of a shaft portion of a second embodiment of an expanded or deployed single-balloon flow control member with a porous window.  
         [0021]    [0021]FIG. 7 is a side view of the aortic catheter of FIG. 6 deployed or expanded in the aorta of a patient, showing the porous window aligned with the ostia of the arch vessels.  
         [0022]    [0022]FIG. 8 is a side view of a third alternate embodiment of the primary flow control member of the present invention wherein the porous middle portion of the primary flow control member has a deployed diameter less than the deployed diameter of the proximal and distal ends.  
         [0023]    [0023]FIG. 9 is a side view of an alternate embodiment of the primary flow control member of the invention with a porous window, where the middle portion of the flow control member has a deployed diameter less than the deployed diameter of the proximal and distal ends of the flow control member.  
         [0024]    [0024]FIG. 10 is a side view of an embodiment where the flow control member of the invention comprises an inner balloon and an outer balloon.  
         [0025]    [0025]FIG. 11 is a side view of an embodiment of the primary flow control member wherein the primary flow control member is a compound structure comprised of three flow control elements.  
         [0026]    [0026]FIG. 12 is a side view of another embodiment of the primary flow control member wherein the primary flow control member is a compound structure comprised of two flow control elements deployed in a patients aorta.  
         [0027]    [0027]FIG. 13 is a side view of an embodiment of the primary flow control member wherein the primary flow control member is a compound structure comprised of three flow control elements with a filter mesh coupled to and deployed between them.  
         [0028]    [0028]FIG. 14 is a side view of another embodiment of the primary flow control member wherein the primary flow control member is a compound structure comprised of two valve flow control elements and one porous inflatable balloon flow control member.  
         [0029]    [0029]FIG. 15 is a side view of another embodiment of the primary flow control member wherein the primary flow control member is a compound structure comprised of two end cap valve flow control elements and one porous inflatable balloon flow control element partially received within each valve element.  
         [0030]    [0030]FIG. 16 is a side view of an embodiment of the primary flow control member similar to that shown in FIG. 15, except the valve elements are conical.  
         [0031]    [0031]FIG. 17 is a side view of the embodiment of the primary flow control member similar to that shown in FIG. 15 deployed within a patient&#39;s aortic arch, and showing the distal valve element partially collapsed.  
         [0032]    [0032]FIG. 18 is a side view of an embodiment of the primary flow control member of the invention configured for antegrade deployment.  
         [0033]    [0033]FIG. 19 is a side view of an embodiment the catheter of the invention further comprising an auxiliary flow control member positioned in the patient&#39;s descending aorta. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0034]    Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the separate embodiments, the catheter described herein with all of its preferred features represents a versatile device having multiple uses. The invention provides a catheter having a primary flow control member positioned near the distal end of the catheter for occluding a first body lumen at a point where a second body lumen branches from the first body lumen and for perfusing the branch lumen. However, the invention will be described more specifically herein relating to an aortic catheter having a primary flow control member configured to be positioned in the aortic arch and having a length sufficient to cover the ostia of the arch vessels. The primary flow control member may have at least one permeable or mesh portion in fluid communication with the ostia of the arch vessels, and may be an inflatable balloon, or include one or more inflatable balloons, or one or more selectively deployable external catheter valves as subunits thereof, or a combination of balloons and valves as subunits thereof. The catheter is characterized by a flexible catheter shaft placed by surgical cutdown or needle/introducer guidewire technique into the vessels of the lower or upper extremity or neck. Larger internal vessels may also be used. Alternatively, the catheter may be introduced centrally through direct penetration of the ascending aorta.  
         [0035]    In some embodiments, filtration may be an important feature of the invention. To filter blood and effectively capture embolic material without unduly disrupting blood flow, the porous section or sections must include an appropriate combination of characteristics including effective filter surface area and pore size, which combination will vary depending on a number of factors including the fluid pressure inside the catheter. For filters comprised of a mesh, the thread diameter is another important characteristic to consider. Typically, the flow rates required in the arch vessels total between 0.5 and 1.5 L/min depending on a variety of factors including the size of the patient and the temperature of the perfusate. Pore size is preferably 500 μm or less, more preferably 200 μm or less, and most preferably 50 μm or less, but larger than at least a red blood cell. However, small filter surface areas disclosed in some embodiments may require larger pore sizes than those given above in order to achieve the necessary rate of flow at an acceptable pressure.  
         [0036]    Once appropriate physical characteristics are determined, suitable meshes can be found among standard meshes known in the art. For example, polyester meshes may be used, such as meshes made by Saati Corporations and Tetko, Inc. These are available in sheet form and can be easily cut and formed into a desired shape. Other meshes known in the art, which have the desired characteristics are also suitable.  
         [0037]    Anticoagulants or antithrombogenic compounds may be applied to the mesh to reduce the chances of blood clotting on the mesh. The anticoagulants or antithrombogenic compounds may be painted, dipped, sprayed or chemically bonded onto the mesh and/or onto other parts of the catheter or the catheter lumens. Other methods known in the art for applying anticoagulants or antithrombogenic compounds may also be used. Anticoagulants, such as heparin and heparinoids, may be used. Anticoagulants other than heparinoids may also be used, for example monoclonal antibodies such as ReoPro.  
         [0038]    Perfusion of blood to the arch vessels will preferably be performed with a pressure drop through the catheter and across the filter of less than approximately 300 mm Hg, more preferably less than approximately 100 mm Hg, in order to reduce hemolysis while providing a blood flow preferably between 0.5 to 1.5 liters per minute. Preferred perfusion pressures may be different for perfusates that do not contain blood and therefore are not subject to hemolysis.  
         [0039]    [0039]FIG. 1 illustrates the shaft portion of a first embodiment of the invention having a primary flow control member  110 . FIG. 2 is a magnified lateral cross section of the aortic catheter taken along line  2 — 2  in FIG. 1. The aortic catheter  100  has an elongated catheter shaft  102  having a proximal portion  104  that preferably extends out of the patient&#39;s body, and a distal end  106  adapted to extend into the patient&#39;s aorta. The elongated catheter shaft  102  should have an overall length sufficient to reach from the arterial access point where it is inserted into the patient to its deployed position within the aorta. For femoral artery deployment in adult human patients, the elongated catheter shaft  102  preferably has an overall length from approximately 60 cm to 120 cm, and more preferably 70 cm to 90 cm.  
         [0040]    Referring to FIG. 2, which is a cross section of the catheter shaft  102  taken along line  2 — 2  of FIG. 1, the elongated catheter shaft  102  preferably has at least four lumens, an inflation/perfusion lumen  108  that provides blood to the primary flow control member  110  and to the arch vessels through the flow control member perfusion ports  112 , a pressure lumen  114  opens to a pressure port  177 , a guidewire lumen  116 , and a corporeal perfusion lumen  118  that is used to perfuse the descending aorta through the corporeal perfusion ports  126 . The configuration of the lumens shown is for illustrative purposes only, and other configurations may be used. For example, in alternate embodiments the catheter shaft  102  may not include a corporeal perfusion lumen  118  or pressure lumen  114  that will help simplify the manufacture of the aortic catheter  100 . In configurations where corporeal perfusion is not integrally built into the aortic catheter, corporeal perfusion may be provided by a coaxial, collateral or contralateral arterial cannula. Alternatively, additional lumens may be included such as perfusion lumens, monitoring lumens or validation of catheter placement lumens.  
         [0041]    In a preferred embodiment, the elongated catheter shaft  102  has an outer diameter that is preferably approximately 9 to 26 French (3.0 to 8.7 mm), and more preferably 12 to 18 French (4.0 to 6.0 mm) for use in adult human patients. Catheters for pediatric use, or use in non-human subjects, may require different dimensions and would be scaled accordingly. The elongated catheter shaft  102  is preferably formed of a flexible thermoplastic material, a thermoplastic elastomer, or a thermoset elastomer. Suitable materials for use in the elongated catheter include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites.  
         [0042]    The primary flow control member  110 , of FIG. 1, is mounted proximal the distal end  106  of the elongated catheter shaft  102  or alternatively may extend beyond the distal end  106 . The flow control member  110  is intended to fulfill at least one and preferably all four of the following functions: (1) occluding the aorta at the aortic arch, (2) selectively perfusing one or more of the coronary arteries, the arch vessels, or the descending aorta with a selected fluid, (3) providing filtered perfusion to one or more of the coronary arteries, the arch vessels, or the descending aorta, and (4) resisting migration of the primary flow control member  110  or cannula  100 .  
         [0043]    [0043]FIG. 3 illustrates the flow control member  110  of FIG. 1 in the expanded or deployed position. The expandable flow control member may be mounted to the exterior of the catheter shaft by heat bonding, heat welding, with an adhesive or by mechanical or frictional means. The flow control member  110  comprises a balloon having a distal end  120 , a middle portion  122 , and a proximal end  124 . The distal end  120  and the proximal end  124  are preferably formed of a nonporous material creating at least one occlusive end, while the middle portion is preferably formed of a mesh or porous material. The inflatable flow control member  110  has a deflated state  110 ′ as illustrated with reference to FIG. 1, in which the diameter of the flow control member is, preferably, not substantially larger than the diameter of the catheter shaft  102  and an inflated state  108  in which the flow control member  110  expands to a diameter sufficient to at least partially occlude blood flow in the aortic arch of a patient. For use in adult humans, the flow control member  110  preferably has an inflated outer diameter of approximately 1 to 7 cm more preferable 2 to 5 cm. When the primary flow control member  110  comprises an inflatable balloon, whether porous or nonporous, the inflatable balloon may be elastic so that it stretches in proportion to the inflation pressure, or may be flaccid or sack-like so that it inflates at low pressure and reaches its design diameter quickly. The sack-like balloon may be relatively non-compliant at its design diameter or it may be compliant, exhibiting elastic behavior after initial inflation, to closely fit the aortic lumen size and curvature. The material or materials used in the inflatable primary flow control member  110  is preferably characterized by properties that allow an internal pressure within the distal flow control member  110  to be maintained at a sufficient level to occlude the aorta, while also allowing a controlled volume of fluid to escape from the flow control member for perfusing the arch vessels. Suitable materials which may be used for flow control member  110  include polyurethanes, polyethylene terephthalate (PET), polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), latex and polyolefin. Furthermore, the surface of the flow control member may have porous regions that allow a fluid to be perfused at a known rate when a specific pressure is attained while not allowing other porous regions to open until a greater internal pressure in the balloon is attained. For perfusion of the arch vessels, it is preferable that the flow rate provided to the arch vessels be controllable within a range from 0.1 to 2.0 liters per minute, and more preferably within a range from 0.5 to 1.5 liters per minute, depending on a variety of factors. Therefore, the flow control member  110  has material properties that allow for the aforementioned perfusion range while still maintaining occlusion properties when deployed in the aorta.  
         [0044]    The porous and nonporous sections of the primary flow control member  110  may be formed from the same or separate materials. Suitable materials for the nonporous portions of the inflatable flow control member  110  include, but are not limited to, elastomers, thermoplastic elastomers, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers, and reinforced composites thereof. In addition, the outer surface of the flow control member  110  may include a force or friction increasing means such as a friction increasing coating or texture to increase friction between the distal flow control member  110  and the aortic wall when deployed. Suitable materials for the mesh or porous middle portion  122  include, but are not limited to, a perforated polymer film, porous or microporous membranes, TYVEK (spun-bonded polyethylene), GORTEX (expanded PTFE), woven or knit mesh or fabric, or the like.  
         [0045]    Referring now to FIG. 4, to facilitate placement of the catheter  100  within the aorta, and to improve the stability of the catheter  100  in the proper position in the patient&#39;s aorta, a distal region  130  of the aortic catheter  100  may be preshaped to conform to the internal curvature of the patient&#39;s aortic arch. The distal region  130  represents a J-shaped curve of approximately 180 degrees of arc with a radius of curvature of approximately 2 to 4 centimeters, for use in a typical adult human patient and may be reinforced with polymer filaments or metal or both. The distal end  106  of the aortic catheter  100  may also be skewed slightly out of the plane reflecting the forward angulation of the typical patient&#39;s ascending aorta.  
         [0046]    The proximal end/portion  104  of the aortic catheter  100  has fittings for each of the catheter lumens  108 ,  114 ,  116 , and  118 . The corporeal perfusion lumen  118  is coupled to a Y-fitting  134  having a barb connector  136  for connection to a perfusion pump or the like, and a luer connector  138  for injecting medications or other fluids. In alternate embodiments, the catheter shaft  102  may further include a pressure lumen coupled to a luer connector for monitoring the corporeal perfusion pressure, withdrawing fluid samples, or for injecting medications or other fluids. The flow control member deployment and perfusion lumen  108  is coupled to a Y-fitting  140  having a barb connector  142  for connection to the same perfusion pump  900  a perfusion pump or the like, and a luer connector  144  for injecting medications or other fluids. The arch pressure lumen  114  is coupled to a luer connector  146  for monitoring the arch perfusion pressure, withdrawing fluid samples, or for injecting medications or other fluids. The guidewire lumen  116  is coupled to a Touhy-Borst fitting  148 , or other hemostasis valve. In alternate embodiments having an auxiliary flow control member and where separate lumens are desired for deploying the auxiliary flow control member, additional fittings suitable for connecting to a syringe or other inflation or deployment device would be provided.  
         [0047]    Illustrated in FIG. 5 is the flow control member  110  deployed in the aorta illustrating the functional features and material attributes of the control member  110  in use. The flow control member  110  is positioned within the aortic arch with the porous middle portion  122  covering the ostia of the arch vessels. A selected fluid, such as oxygenated nonnothermic blood, oxygenated hypothermic blood, blood substitutes such as PERFLUBRON or other perfluorocarbon compounds, radiopaque dyes for angiography, or the like, is introduced through the flow control member inflation and perfusion lumen  108  into the inflatable flow control member  110 . Some selected fluid may seep out through the porous middle portion  122  during inflation, but at a rate less than the rate at which the selected fluid enters the flow control member  110 . In an alternate embodiment, it may be preferable to initially inflate the flow control member  110  with a more viscous solution, for example a radiopaque contrast agent mixed with saline, that will flow through the porous middle portion  122  at a rate slower than the selected perfusion fluid will leak.  
         [0048]    When the correct pressure is attained, the flow control member  110  occludes blood flow through the aortic lumen. The selected fluid used to inflate the flow control member  110  may escape through the porous portion  122  at a known rate into the arch vessels. The flow rate may be adjustable by adjusting the pressure within the flow control member  110 . Contact with the aortic wall and the middle porous portion  122  of the flow control member  110  will reduce or prevent seepage of the selected fluid through sections of the porous middle portion  122  of the flow control member  110  not aligned with the arch vessels. The middle porous portion  122  of the flow control member  110  contacting the aortic wall may also provided resistance to the migration of the flow control member  110  or cannula  100 .  
         [0049]    Preferably, the aortic catheter  100  includes one or more location markers  128 , such as radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  100  during deployment using standard fluoroscopy, ultrasound, MRI, MRA, transesophageal echocardiography, or other techniques. A radiopaque location marker  128  may be formed as a ring or disk of dense radiopaque metal such as gold, platinum, tantalum, tungsten, or compounds or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material.  
         [0050]    In use, the catheter  100  is advanced up the descending aorta and across the aortic arch, under fluoroscopic or ultrasound guidance with the aid of a guidewire within the guidewire lumen  116 . The aortic catheter  100  is advanced until the primary flow control member  110  is positioned in the aortic arch. This may be determined by reference to the radiopaque marker or markers  128 . Using a multihead cardiopulmonary bypass pump or the like, perfusion of oxygenated blood is started through the perfusion ports  112 . The flow control member  110  is then inflated to occlude the aortic arch using a selected perfusion fluid such as oxygenated blood. When the correct pressure is achieved, the perfusion fluid flows from the flow control member  110  and enters the arch vessels. The rate of flow of the perfusion fluid may be controlled by adjusting the pressure within the flow control member  110 . At the completion of the surgical procedure, the flow control member  110  is allowed to deflate, allowing oxygenated blood to flow from the heart to the arch vessels, the descending aorta, and to the coronary arteries. The heart should then spontaneously resume normal sinus rhythm, however, if necessary, cardioversion or defibrillation shocks may be applied to restart the heart. The patient is then weaned off the bypass and the aortic catheter, and other cannulas, are withdrawn. The alternate embodiment configured for antegrade deployment would be used similarly, except that access to the patient&#39;s circulatory system would be made through a central access by an aortotomy or incision directly into the ascending aorta.  
         [0051]    Modification of the operational characteristics or procedures set forth above for use in vessels other than the aorta for perfusion of blood to branch vessels are readily ascertainable by those skilled in the art in view of the present disclosure.  
         [0052]    In an alternate embodiment seen in FIGS. 6 and 7, the flow control member  150  comprises a nonporous balloon with a porous window  152 . In this variation, the catheter  100  may be made of the same materials as those described in relation to the catheter  100  of FIGS. 1 through 5. Common numbers refer to common assembly components, therefore the description of these parts as explained in connection with FIGS. 1 through 4 is incorporated by reference into this illustrative embodiment and all others to follow. The relative position, size and shape of the porous window  152  is provided only as an example and any size shape or configuration may be implemented. In this example, the porous window  152  is positioned approximately symmetrically with respect to the balloon-shaped flow control member  150 . FIG. 7 shows the aortic catheter of FIG. 6 deployed within a patient&#39;s aorta illustrating the relative position of the porous window  152  relative to the ostia of the arch vessels. In this example, the porous window  152  is positioned asymmetrically with respect to the balloon-shaped flow control member  150  to accommodate a variation in the geometry of a patient&#39;s aortic arch.  
         [0053]    In an alternate embodiment shown in FIG. 8, the flow control member  160  includes a porous middle portion  162  with an inflated or deployed diameter less than the diameter of the aortic lumen when the proximal  124  and distal  120  ends are expanded and occluding the aorta. In the embodiments wherein the middle porous section contacts the aortic lumen the effective perfusion area may be limited to the area at the openings of the ostia since the rest of the porous portion will be effectively occluded by the aortic wall. The advantage of the configuration associated with FIG. 8 is that the middle porous section  162  avoids substantial contact with the aortic wall allowing a greater effective filter and perfusion surface area to the arch vessels since perfusion is free to pass through all the mesh material and into the arch vessels. This enables a finer mesh to be used since the effective filter and perfusion surface area is not limited to the openings of the arch vessels.  
         [0054]    The occlusion member  160  of FIG. 8 may be made of different materials which will enable the proximal and distal ends to be more easily inflatable or expandable than the middle porous portion  162  which has the resultant effect of differing outer diameter proportions. For example, the proximal  124  and distal  120  ends may be made of a flexible elastomer such as silicone or latex and the middle portion may be made of a less flexible polyurethane or nylon. Alternatively, another way to achieve the larger ends and a narrower middle portion is to use mechanical supports, external clamps, external heat shrink or the like on the middle portion to essentially restrict the middle portion relative to the ends. In addition, a single material can be used and the desired shape can be achieved by varying the wall thickness of the occlusion member  160 . For example, dipping, molding or extruding the occlusion member are all methods, which may be utilized for creating an occlusion member having a varying wall thickness. Furthermore, the ends of the occlusion member  160  may be fatigued through the manufacturing process to create a thinner or more flexible material.  
         [0055]    The embodiment seen in FIG. 9 discloses a flow control member  170  comprising a nonporous balloon with a porous window  172 . The relative position, size and shape of the porous window  172  is provided only as an example, and in other embodiments the porous window  172  may be any desirable position, size or shape. The catheter of FIG. 9 is otherwise similar to the catheter of FIG. 8 as previously described, and the same benefit of increased filter surface area may be obtained. In this embodiment, the smaller diameter of the middle portion also reduces the criticality of positioning the window  172  over the ostia of the arch vessels.  
         [0056]    In another embodiment, seen in FIG. 10, a flow control member  180  comprises a first outer flow control element or outer balloon  187  and a second inner flow control element or inner balloon  184  positioned within the first outer balloon  187 . The first outer balloon  182  comprises a porous material or includes one or more porous sections  182 . The second inner balloon  184  is preferably nonporous. When the second inner balloon  184  is fully inflated, the outer surface of the second inner balloon  184  contacts the inner surface of the first outer balloon  187  preventing escape of perfused fluid through the porous sections of the first outer balloon  187 . When the first inner balloon  187  is fully or partially deflated, perfusion is allowed to resume through outer balloon  187 . In this embodiment, separate lumens connecting to the outer balloon port  186  and the inner balloon port  181  are required for inflating and deflating the first outer balloon  182  and the second inner balloon  184  independently of each other.  
         [0057]    In embodiments seen in FIGS. 11 through 17, the catheter  100  is shown and will be described having a flow control member comprising a plurality of flow control elements. For example, FIG. 11 discloses a flow control member  190  comprising a set of three adjacent flow control elements. In this embodiment, the flow control elements include a first balloon  192 , a second balloon  194 , and a third balloon  196 . In alternate embodiments, any desirable or practical valves, may be substituted for balloons  192  and  196 .  
         [0058]    The first balloon  192 , located nearest the distal end  106  of the aortic catheter  100 , is preferably comprised of a nonporous material, and is intended to occlude the ascending aorta between the coronary arteries and the arch vessels, and to prevent fluid perfused through the second porous balloon  194  from entering the ascending aorta in a retrograde direction. The second porous balloon  194  is positioned adjacent the proximal side of the first balloon  192 . The second balloon  194  is preferably formed of a porous material, includes porous sections, or includes other means for allowing a controlled flow rate of perfused fluid to pass through. The third balloon  196  is located adjacent the second balloon  194  and is preferably comprised of a nonporous material. In variations where the aortic catheter  100  is to be introduced directly into the ascending aorta the balloon position is reversed relative to the aorta such that the first occlusion balloon  192  resides in the descending aorta and the third occlusion balloon  196  resides in the ascending aorta. The purpose of the third balloon  196  is primarily for occluding the aorta to prevent fluid perfused through the porous second balloon  194  from entering the descending aorta. The porous second balloon  194  may be configured with a deployed diameter equal to or greater than the aortic lumen in order to contact the aortic wall after inflation, or it may be configured with a deployed diameter smaller than the aortic lumen so that, after inflation, it is not in substantial contact with the aortic lumen. The advantage of configuring the second porous balloon  194  to contact the aortic wall is that the force or friction generated by contact with the aortic wall may resist migration of the flow control member  190 . The advantage of configuring the porous second balloon to avoid substantial contact with the aortic wall is that a greater effective filter surface area is achieved because perfusion may not be limited to passing through the mesh material over the arch vessels, consequently, a finer mesh may be used while still achieving a desired flow rate at a desired pressure.  
         [0059]    Another embodiment of the distal flow control member is seen in FIG. 12, which discloses a flow control member  200  comprising two flow control elements  202  and  204  spaced apart so that, in use, one flow control element is positioned on each side of the arch vessels. In the embodiment shown, the flow control elements  202  and  204  comprise inflatable balloons. The first flow control element  202 , located nearest the distal end of the aortic catheter  200 , preferably comprises a nonporous section  206  on the distal side of the flow control element  202 , and a porous section  208  located on the proximal side of the flow control element  202 . The second flow control element  204  preferably comprises a nonporous section  210  located on the proximal side of the flow control element  204 , and a porous section  212  located on the distal side of the flow control element  204 . The deployment/perfusion ports  206  are located in the first and second flow control elements  202  and  204 . The same or separate inflation/perfusion lumens may be used for flow control elements  202  and  204 . In an alternate embodiment, only one of the balloons  202  or  204  may include a porous section. Alternatively, the first flow control element  202  and second flow control element  204  may be reversed in orientation such that the non-permeable portions are reversed with respect to the permeable portions. In this position, cardioplegia may be delivered to the aortic root through permeable portion  208  while blood is delivered to the corporeal body through permeable portion  212  and the arch receives blood through arch perfusion ports  112  at a flow sufficient to maintain the viability of the brain.  
         [0060]    [0060]FIG. 13 discloses a flow control member  220  comprising two flow control elements  222  and  224  spaced apart, as in the previous embodiment, so that, in use, one flow control element is positioned on each side of the arch vessels. However in this embodiment, a mesh or porous filter  226  is coupled between the balloons. In this embodiment, the first and second flow control elements  222  and  224  are nonporous balloons. The balloons may be deployed by using a single deployment/perfusion lumen, or in alternate embodiments, a separate lumen may be used to deploy the flow control elements  222  and  224  independently.  
         [0061]    In alternate embodiments, valves of various varieties, such as those described in U.S. Pat. No. 5,833,671, 5,827,237 by John A. Macoviak and Michael Ross; and U.S. patent application Ser. No. 08/665,635, filed Jun. 17. 1996, by John A. Macoviak and Michael Ross which have previously been incorporated by reference may be used instead of one or more of the inflatable balloons of the flow control elements previously described. For example, FIG. 14 discloses a primary flow control member  240  similar to that disclosed in FIG. 12, comprising a first flow control element  242 , a second flow control element or inflatable balloon  244 , and a third flow control element  246 . However, in this embodiment, flow control elements  242  and  246  are valves. Any desirable or practical valves, such as those described in U.S. Pat. Nos. 5,833,671, 5,827,237 by John A. Macoviak and Michael Ross; and U.S. patent application Ser. No. 08/665,635, filed Jun. 17, 1996, by John A. Macoviak and Michael Ross, may be substituted for balloons  192  and  196  which have been described in the previous embodiments. Flow control element  244  is an inflatable balloon comprising a porous material or having porous sections or the like.  
         [0062]    The first flow control element  242  is located nearest the distal end  106  of the aortic catheter  100 , and is intended to occlude the ascending aorta between the coronary arteries and the arch vessels when introduced in the retrograde direction by way of femoral access and is sized and configured to prevent fluid perfused through the balloon  244  from entering the ascending aorta in a retrograde direction. The third flow control element  246  is positioned adjacent the distal side of the balloon  244 . The purpose of the third flow control element  246  is primarily for occluding the aorta to prevent fluid perfused through the second porous balloon from entering the descending aorta and to isolate cardioplegia. The balloon  244  may be configured with a deployed diameter equal to or greater than the aortic lumen in order to contact the aortic wall after inflation, or it may be configured with a deployed circumference smaller than the aortic lumen so that, in use, it is not in substantial contact with the aortic lumen. The advantage of configuring the balloon  244  to contact the aortic wall is that the force or friction generated by contact with the aortic wall may resist migration of the flow control member  240  or cannula  100 . The advantage in configuring the balloon  244  to avoid substantial contact with the aortic wall is that a greater effective filter surface area is achieved because perfusion is not limited to passing through the mesh material of the balloon  244  over the arch vessels. Consequently, a finer mesh may be used. Preferably the catheter shaft  102  includes one or more lumens for deployment of the flow control elements  242  and  246  separate from the inflation/perfusion lumen for balloon  244 .  
         [0063]    In the embodiment shown in FIG. 15, the flow control member  250  is shown with valves  252  and  256  being end cap valves that are deployed by inflation or deployment of the second flow control element  254 . Consequently, the end cap valves  252  and  256  do not require separate deployment lumens, as deployment of the inflatable middle flow control element  254  will deploy them. The end cap valves may be any desired shape or configuration. For example, FIG. 16 shows a flow control member  260  similar to that disclosed in FIG. 15, but with conical end cap valves  262  and  266 . The end cap valves may be made of any suitable materials such polyarethanes, polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyolefin, latex and ethylene vinyl acetate (EVA).  
         [0064]    [0064]FIG. 17 shows the embodiment of the catheter of FIG. 15 deployed in an aorta with the first flow control element  252  shown in a semi-collapsed condition. It may be an advantage to wean a patient off cardiopulmonary bypass slowly, after the completion of a procedure, by providing a means for transitioning between complete occlusion of the aorta and perfusion by cardiopulmonary bypass and normal heart function. Reducing the pressure in the second flow control member reduces the support of the flow control members  252  and  256 . Fluid pressure generated by contraction of the ventricle temporarily partially collapses the flow control element  252 . Thus, by adjusting the pressure in the second flow control element  254  downward, a controlled flow of blood from the heart is allowed to enter the arch vessels and/or the descending aorta.  
         [0065]    The previous embodiments have been described using a catheter configured for a retrograde approach to the aorta from a peripheral vessel such as the femoral artery. Each of the described embodiments of the invention could easily be modified for alternate deployment means. For example, FIG. 18 shows a catheter  100  configured for central antegrade deployment in the aortic arch through an aortotomy or direct puncture in the ascending aorta. The catheter  100  and flow control member  270  is configured similarly to that disclosed in FIG. 3, comprising an inflatable balloon with nonporous sections  272  and  276 , and a porous middle portion  274 . In this embodiment, the guidewire lumen  116  may be used for corporeal perfusion after the guidewire is removed or alternatively a separate catheter may be inserted either into the femoral artery or the subclavian to perfuse the corporeal circulation, or alternatively corporeal perfusion can be provided through a corporeal lumen  118  and downstream corporeal port  126  distal to the flow control member  270 . Other embodiments of the invention may be configured for peripheral insertion through the subclavian, femoral or auxiliary arteries, as can be seen in U.S. patent application Ser. No. 09/205,753.  
         [0066]    Any embodiments of the catheter of the invention described above may further include auxiliary flow control members. The auxiliary flow control members may be used to further compartmentalize the patient&#39;s circulatory system, or may be used for other functions such as assisting in securely anchoring the catheter in a chosen position. Accordingly, the auxiliary flow control members may be inflatable balloons, deployable valves, or combinations thereof. An example of an auxiliary flow control member is seen in FIG. 19. The catheter of FIG. 19 is configured similarly to the catheter disclosed in FIG. 4, except that the catheter of FIG. 19 comprises an additional or auxiliary flow control member  292  coupled to the catheter shaft  102  proximate, but spaced apart from, the primary flow control member  290 . The auxiliary flow control member  292  is mounted to the distal portion of the catheter shaft  102  proximal to, but spaced apart from, the primary flow control member  290 . The distance between the primary flow control member  290  and the auxiliary flow control member  292  is between approximately 0.5 cm and 10 cm, and is chosen so that when the aortic catheter  100  is deployed with the primary flow control member  290  over the ostia of the arch vessels, the auxiliary flow control member  292  will be positioned in the descending aorta. Use of an auxiliary flow control member  292  to anchor the catheter  100  may allow the use of a lower inflation pressure in the porous balloon as it is no longer depended on for preventing migration of the catheter  100 . This may avoid possible damage to the aorta, which may result from the use of higher pressures to prevent migration.  
         [0067]    The auxiliary flow control member  292  is shown in this embodiment in the form of an expandable inflatable balloon bonded to the catheter shaft  202  by heat welding or with an adhesive. The auxiliary flow control member  292  preferably has a length that is longer than the length of the primary flow control member  290 , or alternatively may be shorter so long as the function of anchoring the catheter  100  is accomplished. Suitable materials for the inflatable anchor member  292  include, but are not limited to, elastomers, thermoplastic elastomers, polyvinylchloride, polyurethane, polyethylene, polyamides, polyesters, silicone, latex, and alloys or copolymers and reinforced composites thereof In addition, the outer surface of the anchor member  292  may include a friction increasing means such as a friction increasing coating or texture to increase friction between the anchor member  292  and the aortic wall when deployed. In the embodiment shown, the corporeal perfusion ports  126  are located on the catheter shaft  102  proximate the anchoring member.  
         [0068]    [0068]FIG. 19 illustrates the aortic catheter  100  of the present invention deployed in the aorta illustrating the functional features and material attributes of the flow control member  290  in use. The flow control member  290  is positioned within the aortic arch with the porous middle portion  274  covering the ostia of the arch vessels. A selected fluid, such as oxygenated normothermic blood, oxygenated hypothermic blood, blood substitutes such as PERFLUBRON or other perfluorocarbon compounds, radiopaque dyes for angiography, or the like, is introduced through the flow control member inflation and perfusion lumen  108  into the inflatable flow control member  290 . Some selected fluid may seep out through the porous middle portion  274  during inflation, but at a rate less than the rate at which the selected fluid enters the flow control member  290 . In an alternate embodiment, it may be preferable to initially inflate the flow control member  290  with a more viscous solution, for example a radiopaque contrast agent mixed with saline, that will flow through the porous middle portion  274  at a rate slower than the selected perfusion fluid will leak.  
         [0069]    When the correct pressure is attained, the flow control member  290  occludes blood flow through the aortic lumen. The selected fluid used to inflate the flow control member  290  may escape through the porous portion  274  at a known rate into the arch vessels. The flow rate may be adjustable by adjusting the pressure within the flow control member  290 . Contact with the aortic wall and the middle porous portion  274  of the flow control member  290  will reduce or prevent seepage of the selected fluid through sections of the porous middle portion  274  of the flow control member  290  not aligned with the arch vessels. The middle porous portion  274  of the flow control member  290  contacting the aortic wall may also provided resistance to the migration of the flow control member  290  or cannula  100 .  
         [0070]    Preferably, the aortic catheter  100  includes one or more location markers  128 , such as radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  100  during deployment using standard fluoroscopy, ultrasound, MRI, MRA, transesophageal echocardiography, or other techniques. A radiopaque location marker  128  may be formed as a ring or disk of dense radiopaque metal such as gold, platinum, tantalum, tungsten, or compounds or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material.  
         [0071]    In use, the catheter  100  is advanced up the descending aorta and across the aortic arch, under fluoroscopic or ultrasound guidance with the aid of a guidewire within the guidewire lumen  116 . The aortic catheter  100  is advanced until the primary flow control member  290  is positioned in the aortic arch. This may be determined by reference to the radiopaque marker or markers  128 . Using a multihead cardiopulmonary bypass pump or the like, perfusion of oxygenated blood is started through perfusion lumen  108  and out the perfusion ports  112 . The flow control member  290  is then inflated to occlude the aortic arch using a selected perfusion fluid such as oxygenated blood. When the correct pressure is achieved, the perfusion fluid flows from the flow control member  290  and enters the arch vessels. The rate of flow of the perfusion fluid may be controlled by adjusting the pressure within the flow control member  290 . At the completion of the surgical procedure, auxiliary member  292  is deflated and thereafter the flow control member  290  is allowed to deflate, allowing oxygenated blood to flow from the heart to the arch vessels, the descending aorta, and to the coronary arteries. The heart should then spontaneously resume normal sinus rhythm, however, if necessary, cardioversion or defibrillation shocks may be applied to restart the heart. The patient is then weaned off the bypass and the aortic catheter, and other cannulas, are withdrawn. The alternate embodiment configured for antegrade deployment would be used similarly, except that access to the patient&#39;s circulatory system would be made through a central access by an aortotomy or incision directly into the ascending aorta.  
         [0072]    In use, the aortic catheter  100  of any of the embodiments described above is introduced into the patient&#39;s circulatory system through a peripheral artery such as the femoral artery, by the percutaneous Seldinger technique, through an introducer sheath, via an arterial cutdown or centrally by means of a median sternotomy or mini-thorocotmy.  
         [0073]    Modification of the operational characteristics or procedures set forth above for use in vessels other than the aorta for perfusion of blood to branch vessels are readily ascertainable by those skilled in the art in view of the present disclosure.