Abstract:
A circulatory support system and method for circulatory support are described for performing cardiopulmonary bypass using differential perfusion and/or isolated segmental perfusion of the circulatory system. The circulatory support system includes one or more venous cannulae for draining blood from the venous side of the patient&#39;s circulatory system, one or more arterial cannulae for perfusing the arterial side of the patient&#39;s circulatory system, and one or more blood circulation pumps connected between the venous cannulae and the arterial cannulae. The arterial cannulae and the venous cannulae of the circulatory support system may take one of several possible configurations. The circulatory support system is configured to segment a patient&#39;s circulatory system into one or more isolated circulatory loops. The circulatory loops may be isolated from one another and/or from the remainder of the patient&#39;s circulatory system on the venous side, as well as on the arterial side, for isolated closed loop circulatory support of separate organ systems. The circulatory support system is suitable for use in minimally-invasive cardiac surgery, using thoracoscopic, port-access or minithoracotomy techniques, or for standard open-chest cardiac surgery.

Description:
This application claims the benefit of Provisional Application No. 60/084,835 filed May 8, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to circulatory support systems and cardiopulmonary bypass systems. More particularly, it relates to a circulatory support system and method of use for isolating organ systems for separate closed loop perfusion. 
     BACKGROUND OF THE INVENTION 
     Circulatory support systems are used in many different medical settings to supplement or to replace the pumping function of a patient&#39;s heart. Applications of circulatory support systems and methods include, inter alia, augmenting cardiac output in patients with a failing heart, resuscitating victims of severe trauma or injury, and supporting a patient&#39;s circulatory functions during surgery. 
     One particular type of circulatory support system, known as a cardiopulmonary bypass (CPB) system, is used to temporarily replace the functions of the heart and the lungs by supplying a flow of oxygenated blood to the patient&#39;s circulatory system. The CPB system drains deoxygenated blood from the patient&#39;s venous system, passes it through a blood oxygenator, and pumps the oxygenated blood back into the patient&#39;s arterial system. CPB systems may be configured for direct cannulation of the inferior and superior vena cava or the right atrium and the aorta, or they may be configured for peripheral cannulation through the femoral vein or jugular vein and the femoral artery. The cardiopulmonary bypass system allows the patient&#39;s heart to be temporarily stopped, for example by cardioplegic arrest, hypothermic arrest or fibrillation, for performing a variety of cardiothoracic surgical procedures. 
     Previous CPB systems have generally been configured to provide a single circulatory loop for supplying the entire body with oxygenated blood from a single CPB pump. Thus, all organ systems of the body receive oxygenated blood at the same pressure and temperature and with the same blood composition. This single-loop configuration has significant limitations in many medical circumstances. It has been found, for instance, that the optimal perfusion temperature for organ preservation during prolonged circulatory support is different for different organs of the body. Likewise, different chemical compositions of the blood are beneficial for preservation of different organ systems. For optimal preservation of all the organ systems within the body, it would be desirable to be able to selectively perfuse different organ systems with different perfusates, which have been optimized for each of the organ systems. 
     U.S. Pat. Nos. 5,308,320, 5,383,854, 5,820,593 and 5,879,316 by Peter Safar, S. William Stezoski and Miroslav Klain, describe a cardiopulmonary bypass system capable of segmenting a patient&#39;s aorta and for selectively perfusing the different segments of the aorta with perfusates of different temperatures or chemical compositions. Other U.S. patents that address the concept of selective aortic perfusion include commonly owned, copending patent applications; 08/909,293, filed Aug. 11, 1997; 08/909,380, filed Aug. 11, 1997, and 09/152,589 filed Aug. 11, 1998 by Safar et al.; and U.S. Pat. No. 5,738,649 and commonly owned copending patent application 09/060,412 filed Apr. 14, 1998 by John A. Macoviak; and U.S. Pat. Nos. 5,827,237 and 5,833,671 by John A. Macoviak and Michael Ross and commonly owned copending patent application 08/665,635, filed Jun. 17, 1996; filed Jun. 18, 1996, by John A. Macoviak and Michael Ross; and 60/067,945, filed Dec. 8, 1997, by Bresnahan et al. These patent applications and all other patents referred to herein are hereby incorporated by reference in their entirety. The balloon catheter of Safar et al. may be introduced into the patient&#39;s aorta from a peripheral entry point, such as the femoral artery or the subclavian artery, or it may be introduced by a direct puncture in the patient&#39;s aorta during open chest surgery. 
     The previously described system, however, does not isolate the segments of the circulatory system from one another on the venous side of the circulatory system because the blood from each of the segments mingles together. Thus, any organ preserving temperature gradients, chemicals or therapeutic agents introduced into one of the segments will eventually mix with and be diluted into the entire systemic blood supply. In many circumstances it would be desirable to at least partially segment blood flow on the venous side of the circulatory system. For example, when administering anesthesia to a patient during surgery, it may be desirable to limit the flow of the anesthetic to the cerebral circulation only and to avoid dilution of the anesthetic in the systemic blood supply, and even to recirculate the anesthetic to the cerebral circulation. As another example, when administering a therapeutic agent that is very costly or which has systemic, central or specific organ toxicity or other undesirable effects, it may be desirable to limit the flow of the therapeutic agent to the target organs as much as possible without it entering the systemic blood supply such as gene therapy, viral vectors protein plasmids and angiogenic genes. As a third example, when performing segmented selective perfusion combined with hypothermic organ preservation, it would be desirable to isolate the segments of the circulatory system on the venous side to allow more precise and efficient temperature control within each circulatory loop. It would be desirable, therefore, to provide a circulatory support system or cardiopulmonary bypass system that allows segmentation of the circulatory system on the venous side, as well as on the arterial side, for isolated closed loop circulatory support of separate organ systems. Such a closed loop circulatory support system may be used to supply the entire body; with blood or other fluids through a plurality of isolated circulatory loops when the heart is not pumping. Alternatively, the closed loop circulatory support system may be used to create a single circulatory loop for supplying a single segment or organ system of the body with blood or other fluids while the beating heart supplies blood to the remainder of the body. 
     A plethora of known and newly discovered organ preserving chemicals and therapeutic agents are suitable for use with the circulatory support system of the present invention. Among these are natural and artificial blood substitutes or oxygen carriers, such as free hemoglobin, PERFLUBRON, and perfluorocarbons, and hemoglobin modifiers, such as RSR-13 (Allos Therapeutics), that increase oxygen delivery from blood to tissues. Also among these are neuroprotective agents, which have been the subject of intensive research in recent years. Promising neuroprotective agents include Na +  blockers, glutamate inhibitors, nitric oxide inhibitors and radical scavengers. A thorough treatment of this subject can be found in the book  Neuroprotective Agents , published by the New York Academy of Sciences. Possible therapeutic agents include, inter alia, thrombolytic agents, such as tPA, streptokinase and urokinase as well as gene therapy including angiogenic genes. 
     SUMMARY OF THE INVENTION 
     The circulatory support system of the present invention generally includes one or more venous cannulae for draining blood from the venous side of the patient&#39;s circulatory system, one or more arterial cannulae for perfusing the arterial side of the patient&#39;s circulatory system, and one or more blood circulation pumps connected between the venous cannulae and the arterial cannulae. The arterial cannulae and the venous cannulae of the circulatory support system may take one of several possible configurations. The circulatory support system is configured to segment a patient&#39;s circulatory system into one or more isolated circulatory loops. The circulatory loops may be isolated from one another and/or from the remainder of the patient&#39;s circulatory system on the venous side, as well as on the arterial side, for isolated closed loop circulatory support of separate organ systems. The circulatory support system of the present invention is suitable for use in minimally-invasive cardiac surgery, using thoracoscopic, port-access or minithoracotomy techniques, or for standard open-chest cardiac surgery. 
     Also disclosed is a method for circulatory support and for cardiopulmonary bypass using differential perfusion and/or isolated segmental perfusion of the circulatory system. According to the method, a patient&#39;s circulatory system is segmented into two or more regions that are perfused with perfusate at different temperatures and/or different chemical compositions and/or different flow rates and/or different pressures. The regions may be isolated from one another and/or from the remainder of the patient&#39;s circulatory system on the venous side, as well as on the arterial side, for isolated closed loop circulatory support of separate organ systems. 
     In one variant of the method, a cerebral loop, a cardiac loop and a corporeal loop are created. A first fluid, preferably containing oxygenated blood, is circulated to the cerebral loop at a relatively low temperature of approximately 32° C. or lower for deep protective hypothermia of the brain. Neuroprotective agents may be added to the first fluid to enhance the protection. A second fluid, which may include a cardioplegic agent, is circulated to the cardiac loop at a moderate temperature between 32° C. and 37° C. for mild hypoihermia of the heart to protect the myocardium, while avoiding arrhythmias that can be caused by deep hypothermia. A third fluid, preferably containing oxygenated blood, is circulated to the corporeal loop at approximately 37° C. for normothermic support of the remainder of the body. The venous side of the circulatory system may likewise be divided three ways so that the cerebral loop, cardiac loop and corporeal loop which are at least partially isolated from one another. Alternatively, the venous side of the circulatory system may be divided two ways so that the cardiac loop combines with either the cerebral loop or corporeal loop on the venous side, or the flow from all three loops may be allowed to commingle on the venous side of the circulatory system. 
     The use of differential perfusion according to this method provides several other clinical advantages in addition to those discussed above. The use of differing degrees of hypothermia allows optimal protection of the brain and of the heart during cardiopulmonary support, while decreasing the likelihood of complications. This method reduces the thermal mass of the tissue that must be cooled and rewarmed during the procedure. In addition, normothermic corporeal circulation provides a large reservoir of stored thermal energy for assisting in rewarming the heart and the brain at the end of the procedure. Both of these factors will result in decreasing the procedure time for surgery requiring cardiopulmonary bypass. 
     Still other clinical advantages exist with a closed loop circulatory system of the present invention. By isolating the cerebral, myocardial and corporeal circulation on the venous side (outputs) as well as the arterial side (inputs), isolated measurements in the aortic arch, aortic root, and corporeal circulation can be monitored in relation to the superior vena cava, right atrium and inferior vena cava respectively. This relationship will enable the clinician to determine oxygen saturation in the cerebral loop and in the corporeal loop to better manage the patient during the surgical procedure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a side view of an aortic catheter according to the present invention with a catheter shaft configured for retrograde deployment via femoral artery access. 
     FIG. 2 is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along line  2 — 2  showing the multi-lumen arrangement of the catheter shaft. 
     FIG. 3 illustrates a side view of a superior vena cava cannula according to the present invention with a tubular shaft configured for introduction into a patient&#39;s venous system through the jugular vein or other peripheral artery. 
     FIG. 4 is a magnified lateral cross sectional of the superior vena cava cannula of FIG. 3 taken along line  4 — 4  in FIG.  3 . 
     FIG. 5 illustrates a side view of an inferior vena cava cannula according to the present invention with a tubular shaft configured for introduction into a patient&#39;s venous system through the femoral vein or other peripheral artery. 
     FIG. 6 is a magnified lateral cross sectional of the inferior vena cava cannula of FIG. 5 taken along line  6 — 6  in FIG.  5 . 
     FIG. 7 is a schematic illustration depicting a first embodiment of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. 
     FIG. 8 is a cutaway close-up view of the cannula placement as shown in FIG. 7 with a portion of the patient&#39;s heart cut away to better show the descending aorta. 
     FIG. 9 illustrates a side view of an aortic catheter according to the present invention with a catheter shaft configured for retrograde deployment via femoral artery access. 
     FIG. 10 is a magnified lateral cross section of the aortic catheter of FIG. 9 taken along line  10 — 10  showing the multi-lumen arrangement of the catheter shaft. 
     FIG. 11 illustrates a side view of a dual lumen venous drainage cannula of the present invention configured for introduction through the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities. 
     FIG. 12 is a magnified lateral cross section of the venous drainage cannula taken along line  12 — 12  of FIG.  11 . 
     FIG. 13 is a magnified lateral cross section of the venous drainage cannula taken along line  13 — 13  of FIG.  11 . 
     FIG. 14 is a schematic illustration depicting a second embodiment of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. 
     FIG. 15 is a cutaway close-up view of the cannula placement as shown in FIG. 14 with a portion of the patient&#39;s heart cut away to better show the descending aorta. 
     FIG. 16 illustrates a side view of an aortic catheter according to the present invention with a coaxial catheter shaft configured for retrograde deployment via femoral artery access. 
     FIG. 17 is a magnified lateral cross section of the aortic catheter of FIG. 16 taken along line  17 — 17  showing the multi-lumen coaxial arrangement of the catheter shaft. 
     FIG. 18 is a magnified lateral cross-section of the aortic catheter of FIG. 16 taken along line  18 — 18  showing the multi-lumen arrangement of the catheter shaft. 
     FIG. 19 illustrates a side view of a coaxial dual lumen venous drainage cannula of the present invention configured for introduction through the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities. 
     FIG. 20 is a magnified lateral cross section of the coaxial dual lumen venous drainage cannula taken along line  20 — 20  of FIG.  19 . 
     FIG. 21 is a magnified lateral cross section of the coaxial dual lumen venous drainage cannula taken along line  21 — 21  of FIG.  19 . 
     FIG. 22 illustrates a third embodiment of the support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. 
     FIG. 23 is a cutaway close-up view of the cannula placement of FIG. 22 with a portion of the patient&#39;s heart cut away to better show the descending aorta. 
     FIG. 24 illustrates an aortic arch perfusion cannula of the present invention configured for introduction into the aortic arch through peripheral arterial access in one of the upper extremities, such as the left or right subclavian artery, axillary artery or brachial artery. 
     FIG. 25 is a magnified lateral cross section of the aortic arch perfusion cannula of FIG. 24 taken along line  25 — 25  of FIG. 24 showing the multi-lumen arrangement of the catheter shaft. 
     FIG. 26 illustrates a corporeal perfusion cannula of the present invention configured for introduction into the descending aorta through a peripheral arterial access in one of the lower extremities, such as the femoral artery. 
     FIG. 27 is a magnified lateral cross section of the corporeal perfusion cannula taken along line  27 — 27  of FIG. 26 showing the multi-lumen arrangement of the catheter shaft. 
     FIG. 28 illustrates a fourth embodiment of the support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. 
     FIG. 29 illustrates a side view of a dual-balloon, selective, central arterial perfusion cannula configured for antegrade introduction into the patient&#39;s aortic arch via a direct puncture or incision in the ascending aorta. 
     FIG. 30 is a magnified lateral cross section of the aortic catheter of FIG. 29 taken along line  30 — 30  in FIG. 29 illustrating the multi-lumen arrangement of the aortic catheter. 
     FIG. 31 illustrates a side view of the central superior vena cava cannula of the present invention configured for introduction into the patient&#39;s superior vena cava via an incision in the right atrium. 
     FIG. 32 is a magnified lateral cross-section of the central superior vena cava cannula taken along line  32 — 32  of FIG.  31 . 
     FIG. 33 illustrates a side view of the central inferior vena cava cannula of the present invention configured for introduction into the patient&#39;s inferior vena cava through the same or another incision in the right atrium. 
     FIG. 34 is a magnified lateral cross-section of the central superior vena cava cannula taken along line  33 — 33  of FIG.  33 . 
     FIG. 35 is a schematic diagram of a fifth embodiment of the circulatory support system of the present invention configured for selective, isolated, dual loop perfusion of a patient&#39;s circulatory system. 
     FIG. 36 is a side view of an aortic perfusion shunt apparatus configured for insertion into a patient&#39;s aorta via a peripheral artery such as the femoral artery. 
     FIG. 37 is a distal end view of the expandable shunt conduit of the aortic perfusion shunt apparatus of FIG. 36 taken along line  37 — 37 . 
     FIG. 38 shows a schematic diagram of a sixth embodiment of the circulatory support system of the present invention configured for selective, closed-loop perfusion of a patient&#39;s cerebral circulation and upper extremities, while the beating heart supplies the viscera and lower extremities with blood. 
     FIG. 39 shows a schematic diagram of a seventh embodiment of the circulatory support system of the present invention configured for selective, closed-loop perfusion of a patient&#39;s renal system, while the beating heart supplies the remainder of the circulatory system with blood. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The circulatory support system of the present invention generally comprises one or more arterial cannulae to enable the segmented perfusion of the patient&#39;s circulatory system. On the arterial side, one or more venous cannulae for enable segmented draining of the patient&#39;s circulatory system on the venous side, and one or more blood circulation pumps connect between the venous cannulae and the arterial cannulae. Preferably, the circulatory support system will also include one or more blood oxygenators and one or more heat exchangers for conditioning the patient&#39;s blood. The circulatory support system is configured to segment a patient&#39;s circulatory system into one or more isolated circulatory loops. The circulatory loops are isolated from one another and/or from the remainder of the patient&#39;s circulatory system on the venous side, as well as on the arterial side, for isolated closed loop circulatory support of separate organ systems. 
     FIGS. 1 through 7 illustrate a first embodiment of the present invention. FIG. 1 illustrates a side view of the aortic catheter  100  according to the present invention with a catheter shaft  102  configured for retrograde deployment via femoral artery access. In order to facilitate placement of the aortic catheter  100  and to improve the stability of the catheter  100  in the proper position in the patient&#39;s aorta, a distal region  144  of the catheter shaft  102  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. The curved distal region  144  represents a J-shaped curve of approximately 180 degrees of arc with a radius of curvature of approximately 2 to 4 cm to match the typical curvature of the aortic arch in an adult human patient. In addition, the distal end  106  of the catheter may be skewed slightly up out of the plane of the curve to accommodate the forward angulation of the patient&#39;s ascending aorta. Additionally, the catheter shaft  102  may be reinforced, particularly in the curved distal region  144 , for example with braided or coiled wire, to further improve the stability of the catheter  100  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 2, is a magnified lateral cross section of the aortic catheter  100  of FIG. 1 taken along line  2 — 2  showing the multi-lumen arrangement of the catheter shaft  102 . The catheter shaft  102  has six lumens: a corporeal perfusion lumen  108 , an arch perfusion lumen  110 , a first balloon inflation lumen  112 , a second balloon inflation lumen  114 , a guide wire and cardioplegia lumen  116  and a root pressure lumen  118 . 
     Referring to FIG. 1 the elongated catheter shaft  102  is preferably formed of a flexible thermoplastic material, a thermoplastic elastomer or a thermoset elastomer. The catheter shaft  102  may be fabricated separately by known extrusion methods and joined together end-to-end, for example by heat welding or by adhesive bonding. Alternatively, the catheter shaft  102  may be fabricated by dipping or by composite construction techniques and joined together or the entire catheter shaft  102  may be fabricated integrally. Suitable materials for the elongated catheter shaft  102  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. 
     An upstream occlusion member  120  is mounted on the catheter shaft  102  near the distal end  106  of the catheter  100 . The upstream occlusion member  120  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  102  by heat welding or with an adhesive. Alternatively, the upstream occlusion member  120  may be in the form of a selectively deployable external catheter valve. For a discussion of other suitable upstream occlusion members as well as the material components thereof, reference is made to commonly owned U.S. Pat. Nos. 5,827,237, and 5,833,671 which have previously been incorporated by reference herein in their entirety and commonly owned copending patent application 09/205,753 filed Dec. 4, 1998, which is herein incorporated by reference. These occlusion members discussed therein are suitable for all embodiments discussed herein in any combination. Suitable materials for the upstream occlusion member  120  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof. In addition, the outer surface of the upstream occlusion member  120  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. The upstream occlusion member  120  has a deflated state, in which the diameter of the occlusion member  120  is preferably not much larger than the diameter of the catheter shaft  102 , and an inflated state, in which the occlusion member  120  expands to a diameter sufficient to occlude blood flow in the ascending aorta of the patient. For use in adult human patients, the inflatable balloon upstream occlusion member  120  preferably has an inflated outer diameter of approximately 1.5 cm to 5.0 cm. Preferably, the inflatable occlusion member  120  has an inflated length that is not significantly longer than its inflated diameter, or more preferably, is shorter than its inflated diameter. This shortened inflated profile allows the upstream occlusion member  120  to be easily placed within the ascending aorta between the coronary arteries and the brachiocephalic artery without any danger of inadvertently occluding either. 
     A downstream occlusion member  122  is mounted on the catheter shaft  102  at a position proximal to and spaced apart from the upstream occlusion member  120 . The downstream anchoring member may be made of the same materials as the upstream anchoring member of different materials and of the same size or a different size. For a complete discussion on the potential sizes and characteristics of the downstream occlusion member, reference is made to commonly owned copending patent application 09/205,753 filed Dec. 4, 1998 which has previously been incorporated by reference. The downstream anchoring members discussed therein are suitable for all embodiments discussed herein in any combination. The distance between the upstream occlusion member  120  and the downstream occlusion member  122  is preferably between 3 and 20 cm, more preferably between 8 and 15 cm, and is chosen so that when the aortic catheter  100  is deployed and the upstream occlusion member  120  is positioned within the ascending aorta between the coronary arteries and the brachiocephalic artery, the downstream occlusion member  122  will be positioned in the descending aorta downstream of the left subclavian artery. The downstream occlusion member  122  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  102  by heat welding or with an adhesive. The downstream occlusion member  122  is more elongate than the upstream occlusion member  120 . Suitable materials for the inflatable balloon downstream anchoring member  122  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof. In addition, the outer surface of the downstream anchoring member  122  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. Alternatively, the downstream occlusion member  122  may be in the form of a selectively deployable valve. 
     The inflatable downstream occlusion member  122  has a deflated state, in which the diameter of the occlusion member  122  is preferably not much larger than the diameter of the catheter shaft  102 , and an inflated state, in which the occlusion member  122  expands to a diameter sufficient to occlude blood flow in the descending aorta of the patient. For use in adult human patients, the downstream occlusion member  122  preferably has an inflated outer diameter of approximately 1.5 cm to 5.0 cm and a length of approximately 1.0 cm to 7.5 cm. The more elongated the occlusion member  122  the greater the anchoring friction against the wall of the descending aorta when the downstream occlusion member  122  is inflated in order to prevent migration of the aortic catheter  100  due to pressure gradients within the aorta during perfusion. 
     The corporeal perfusion lumen  108  extends through the catheter shaft  102  from the proximal end  104  to one or more corporeal perfusion ports  124  on the exterior of the catheter shaft  102  proximal of the downstream occlusion member  122 . The arch perfusion lumen  110  extends through the catheter shaft  102  from the proximal end  104  to one or more arch perfusion ports  126  on the exterior of the catheter shaft  102  between the upstream occlusion member  120  and the downstream occlusion member  122 . The first inflation lumen  112  extends through the catheter shaft  102  from the proximal end  104  to a first balloon inflation port  132  residing in the interior of the downstream occlusion member  122 . The second balloon inflation lumen  114  extends through the catheter shaft  102  from the proximal end  104  to balloon inflation port  130  residing in the interior of the upstream occlusion member  120 . Alternatively, a common balloon inflation lumen can serve to simultaneously inflate and deflate both the upstream occlusion member  120  and the downstream occlusion member  122 . When a common inflation lumen is implemented an arch monitoring lumen (not shown) may be incorporated having an arch monitoring port residing between the upstream occlusion member  120  and the downstream occlusion member  122  to monitor the pressure in the aortic arch. 
     The root pressure lumen  118  extends through the catheter shaft  102  from the proximal end  104  to a root pressure port  128  near the distal end  106  of the catheter shaft  102  to monitor pressure in the aortic root. The guide wire and cardioplegia lumen  116  extends from the proximal end  104  of the catheter shaft  102  to a guide wire/cardioplegia port  136  at the distal end  106  of the catheter shaft  102 , distal to the upstream occlusion member  120 . Preferably, the distal end  106  of the catheter shaft  102  is smoothly tapered or rounded for easy introduction and to avoid trauma or injury to the aortic wall during insertion or withdrawal of the aortic catheter  100 . 
     Preferably, the aortic catheter  100  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  100  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the aortic catheter  100  includes a distal radiopaque marker  138  positioned near the distal end  106  of the catheter shaft  102 , an intermediate radiopaque marker  140  positioned near the proximal edge of the upstream occlusion member  120 , and a proximal radiopaque marker  142  positioned near the distal edge of the downstream anchoring member  122 . Each of the radiopaque markers  138 ,  140 ,  142  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  104  of the catheter shaft  102  is connected to a manifold  150  with fittings for each of the catheter lumens. The corporeal perfusion lumen  108  is connected to a Y-fitting  162  that has a barb connector  152  for connection to a perfusion pump or the like and a luer connector  154 , which may be used for monitoring perfusion pressure, for withdrawing fluid samples or for injecting medications or other fluids. Likewise, the arch perfusion lumen  110  is connected to a Y-fitting  164  that has a barb connector  156  for connection to a perfusion pump and a luer connector  158 . The balloon inflation lumens  112  and  114  are connected to luer connectors  160  and  166  respectively or other fittings suitable for connection to a syringe or balloon inflation device. The guide wire and cardioplegia lumen  116  is connected to a three-way Y-fitting  170  that has a barb connector  172  for connection to a cardioplegia infusion pump, a luer connector  174  and a guide wire port  176  with a Touhy-Borst adapter or other hemostasis valve. The root pressure lumen  118  is connected to a luer connector  168  or other fitting suitable for connection to a pressure monitor. 
     FIG. 3 illustrates a side view of a superior vena cava cannula  399  according to the present invention with a tubular shaft  398  configured for introduction into a patient&#39;s venous system through the jugular vein or other peripheral artery. FIG. 4 is a magnified lateral cross sectional of the superior vena cava cannula  399  of FIG. 3 taken along line  4 — 4  in FIG.  3 . 
     Referring now to FIGS. 3 and 4 collectively, the superior vena cava cannula  399  has a tubular shaft  398  that includes a venous drainage lumen  397  and a balloon inflation lumen  396 . The tubular shaft  398  preferably has a length of approximately 15 cm to 60 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). An occlusion balloon  395  or other expandable occlusion member is mounted on the tubular shaft  398  near the distal end of the cannula  399 . The occlusion balloon  395  or other expandable occlusion member preferably has an expanded diameter of approximately 5 mm to 40 mm. The venous drainage lumen  397  extends through the tubular shaft  398  from a venous drainage fitting  394  to one or more venous drainage ports  393  on the tubular shaft  398  proximal to the occlusion balloon  395 . The venous drainage fitting has a luer connector  373  which may be used for monitoring pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting medications or other fluids, a barb connector  372  or other suitable fitting for being connected to a CPB machine and a guide wire entry connector  392  in the form of a Thouy-Borst fitting or other suitable hemostasis valve for creating a fluid tight seal when using a guide wire. When a guide wire is used the venous drainage lumen  397  serves as an additional guide wire lumen capable of receiving a guide wire  301  which is guided to a guide wire port  374  on the end of the tubular shaft  398  distal to the occlusion balloon  395 . Alternatively, a separate lumen may be provided leading to a port distal to the occlusion balloon  395  wherein a separate monitoring device may be slidably or integrally disposed to give monitoring information inside or outside the cannula  399 , and inside the superior vena cava. The balloon inflation lumen  396  extends through the tubular shaft  398  from a balloon inflation fitting  391  on the proximal end of the cannula  399  to one or more balloon inflation ports  390  within the occlusion member  395 . 
     FIG. 5 illustrates a side view of an inferior vena cava cannula  589  according to the present invention with a tubular shaft  588  configured for introduction into a patient&#39;s venous system through the femoral or other peripheral artery. FIG. 6 is a magnified lateral cross sectional of the inferior vena cava cannula  589  of FIG. 5 taken along line  6 — 6  in FIG.  5 . 
     Referring collectively to FIGS. 5 and 6, the inferior vena cava cannula  589  is configured for introduction into the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities. The inferior vena cava cannula  589  has a tubular shaft  588  that includes a venous drainage lumen  587  and a balloon inflation lumen  586 . The tubular shaft  588  preferably has a length of approximately  15  cm to  90  cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). An occlusion balloon  585  or other expandable occlusion member is mounted on the tubular shaft  588  near the distal end of the cannula  589 . The occlusion balloon  585  or other expandable occlusion member preferably has an expanded diameter of approximately 5 mm to 40 mm. The venous drainage lumen  587  extends through the tubular shaft  588  from a venous drainage fitting  584  on the proximal end of the cannula shaft  588  to one or more venous drainage ports  583  on the tubular shaft  588  proximal to the occlusion balloon  585 . The venous drainage fitting  584  has a luer connector  563  which may be used for monitoring pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting medications or other fluids, a barb connector  562  or other suitable fitting for being connected to a CPB machine and a guide wire entry connector  582  in the form of a Thouy-Borst fitting or other suitable hemostasis valve for creating a fluid tight seal when using a guide wire. When a guide wire is used the venous drainage lumen  587  serves as an additional guide wire lumen configured for receiving a guide wire  501  which is guided to a guide wire port  564  on the end of the tubular shaft  588  distal to the occlusion balloon  585 . Alternatively, a separate lumen may be provided leading to a port distal to the occlusion balloon  585  wherein a separate monitoring device integral or nonintegral is slideably disposed to give monitoring information inside or outside the cannula  589 , and inside the inferior vena cava. The balloon inflation lumen  586  extends through the tubular shaft  588  from a balloon inflation fitting  581  on the proximal end of the cannula  589  to one or more balloon inflation ports  580  within the occlusion balloon  585 . 
     FIG. 7 is a schematic illustration depicting a first embodiment of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. Optionally, the patient&#39;s coronary circulation may be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created. In this embodiment of the circulatory support system, arterial cannulation is provided by a dualballoon, selective arterial perfusion cannula  700 , and venous cannulation is provided by a superior vena cava cannula  799  and a separate inferior vena cava cannula  788 . FIG. 8 is a cutaway close-up view of the cannula placement as shown in FIG. 7 with,a portion of the patient&#39;s heart cut away to better show the descending aorta. 
     Referring now to FIGS. 7 and 8, the cerebral closed loop circulation is created by having venous drainage port  793  proximal to the occlusion balloon  795  in fluid communication with the venous drainage lumen  797 . Connected to the. venous drainage lumen  797  of the superior vena cava cannula  799  is a venous drainage fitting  794  which is connected to inflow tubing  777  in fluid communication with inflow port  751  of a first blood circulation pump  750 . After the. blood is conditioned it is pumped through outflow port  753  which is coupled to outflow tubing  754  in fluid communication with barb connector  756  which is coupled to the arch perfusion lumen  710  of the arterial cannula  700 . The first blood circulation pump  750  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. For illustrative purposes a membrane oxygenator system is provided for the cerebral circulation and a bubble oxygenator is provided for the corporeal circulation. It is understood by those skilled in the art that either oxygenator may be employed. In addition, a system may use two bubble oxygenators, two membrane oxygenators or a membrane oxygenator and a bubble oxygenator or any combination thereof. This illustrative embodiment and all others contained herein may be configured with any combination as so stated. 
     The cerebral loop of the circulatory support system includes a venous drainage cannula  799 , which drains to a venous blood reservoir  701 , the blood is pumped to a heat exchanger  702  and membrane oxygenator  703  in series with the first blood circulation pump. Optionally, vacuum assist (not shown) may be used to enhance venous drainage through the superior vena cava cannula  799 . Venous blood from the head and upper extremities enters the patient&#39;s superior vena cava and is drained out through the venous drainage lumen  797  of the superior vena cava cannula  799 . The blood is oxygenated, cooled and recirculated by the first blood circulation pump  757  to the head and upper extremities through the arch perfusion lumen  710  and out the arch perfusion ports  726  within the arterial cannula  700 . 
     The corporeal loop of the circulatory support system includes a venous drainage cannula  789 , which drains into a combined heat exchange bubble oxygenator to an arterial reservoir where it is pumped to arterial cannula  700 . The venous drainage lumen  787  is fluid communication with drainage port  783  proximal to the occlusion balloon  785  in fluid communication with the venous drainage lumen  787 . Alternatively there can be a venous drainage port  730  distal as well as proximal to the occlusion balloon  785 . Connected to the venous drainage lumen  787  of the inferior vena cava cannula  789  has a venous drainage fitting  784  connected to corporeal inflow tubing  749  in fluid communication with inflow port  748  of the second blood circulation pump  747 . After the blood is conditioned it is pumped through outflow port  746  which is coupled to outflow tubing  745  in fluid communication with barb connector  752  which is coupled to the corporeal perfusion lumen  708  of the arterial cannula  700 . The second blood circulation pump  747  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. The corporeal loop of the circulatory support system includes a venous blood reservoir  706 , a blood oxygenator  705  and heat exchanger  704  in series with the second blood circulation pump. Optionally, vacuum assist (not shown) may be used to enhance venous drainage through the inferior vena cava cannula  789 . Venous blood from the viscera and lower extremities enters the patient&#39;s inferior vena cava and is drained out through the venous drainage lumen  787  of the inferior vena cava cannula  789 . The blood is oxygenated, cooled and recirculated by the second blood circulation pump  747  to the viscera and lower extremities through the corporeal perfusion lumen  708  and out the corporeal perfusion ports  724  of the arterial cannula  700 . 
     Optionally, either the superior vena cava cannula  799  or the inferior vena cava cannula  789  may be made without the occlusion balloon or with additional drainage ports distal to the balloon so that the cannula drains the patient&#39;s right atrium and the coronary sinus as part of the cerebral loop or the corporeal loop, respectively. Alternatively, either the superior vena cava cannula  799  or the inferior vena cava cannula  789  can be made with a separate, second drainage lumen connected to drainage ports positioned distal to the balloon for draining the patient&#39;s right atrium and the coronary sinus. A separate coronary perfusion loop can be created by connecting the second drainage lumen to the inflow of a third blood circulation pump and connecting the outflow of the pump to the cardioplegia lumen of the arterial cannula  700 . The third blood circulation pump may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the coronary loop also includes a venous blood reservoir, a blood oxygenator and heat exchanger in series with the third blood circulation pump. 
     As another alternative, the coronary circulation can be isolated by using a coronary sinus catheter for retrograde administration of cardioplegia into the patient&#39;s coronary arteries. This would eliminate the need for the occlusion balloon on either the superior vena cava cannula  799  or the inferior vena cava cannula  789  and the patient&#39;s right atrium could be drained as part of the cerebral loop or the corporeal loop. For example, a superior vena cava cannula  799  without an occlusion balloon (not shown) or with the balloon deflated (not shown) could be inserted into the superior vena cava and the right atrium via the jugular vein. An inferior vena cava cannula  789  would be inserted into the inferior vena cava via the femoral vein and the occlusion balloon  785  inflated to isolate the corporeal loop. A coronary sinus catheter can be inserted collaterally with the superior vena cava cannula  799  via the jugular vein to isolate the coronary circulation on the venous side and for antegrade or retrograde flow of blood, cardioplegia or other fluids. Suitable coronary sinus catheter for retrograde administration of cardioplegia can be found in U.S. Pat Nos. 5,738,652; 5,722,963; 5,720,726; 5,662,607; 5,653,690; 5,643,231; 5,620,418; 5,617,854; 5,597,377; 5,558,644; 5,549,581; 5,533,957; 5,505,698; 5,488,960; 5,487,730; 5,466,216; 5,423,772; 5,423,745; 5,401,244; 5,395,331; 5,385,548; 5,385,540; 5,324,260; 5,197,952; 5,024,668; 5,021,045; 4,943,277; 4,927,412; 4,753,637; 4,648,384; 4,459,977, which are hereby incorporated by reference in their entirety. 
     To complete the closed loop circulation system an arterial perfusion cannula  700  is provided. The dual-balloon, selective arterial perfusion cannula  700  is configured for retrograde introduction into the patient&#39;s aorta via a peripheral arterial access point, such as the femoral artery. The dual-balloon, selective arterial perfusion cannula  700  has a tubular shaft  702  that includes a corporeal perfusion lumen  708 , an arch perfusion lumen  710 , a guide wire cardioplegia lumen  716 , two balloon inflation lumens  712  and  714  and, a root pressure lumen  718 . An upstream occlusion balloon  720  or other expandable occlusion member is mounted on the tubular shaft  702  so that it is positioned in the ascending aorta between the coronary arteries and the right brachiocephalic artery. A downstream occlusion balloon  722  or other expandable occlusion member is mounted on the tubular shaft  702  so that it is positioned in the descending aorta downstream of the left subclavian artery. The corporeal perfusion lumen  708  extends through the tubular shaft  702  from a corporeal barb connector  752  to one or more corporeal perfusion ports  724  on the tubular shaft  702  proximal to the downstream occlusion balloon  722 . The arch perfusion lumen  710  extends through thetubular shaft  702  from an arch barb connector  756  to one or more arch perfusion ports  726  on the tubular shaft  702  between the upstream occlusion balloon  720  and the downstream occlusion balloon  722 . The guide wire cardioplegia lumen  716  extends through the tubular shaft  702  from a barb connector  772  to one or more cardioplegia ports  736  on the tubular shaft distal to the upstream occlusion balloon  720 . The root pressure lumen  718  extends through the tubular shaft  702  from a pressure fitting  768  to a root pressure port  728  on the tubular shaft  702  distal to the upstream occlusion balloon  720 . A first balloon inflation lumen  712  extends through the tubular shaft  702  a balloon inflation fitting  760  a balloon inflation port  732  within the downstream occlusion balloon  722 . A second balloon inflation lumen  714  extends through the tubular shaft  702  to a balloon inflation fitting  766  to a balloon inflation port  730  within the upstream occlusion balloon  720 . FIGS. 9 through 15 illustrate a second embodiment of the circulatory support system of the present invention, which is also configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. As in the previously described embodiment, the patient&#39;s coronary circulation may optionally be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created. In this embodiment of the circulatory support system, arterial canrulation is provided by a dual-balloon, selective arterial perfusion cannula  900  similar to the one previously described in connection with FIG.  1  and venous cannulation is provided by a dual-lumen venous drainage cannula  1199 . 
     FIG. 9 illustrates a side view of the aortic catheter  900  according,to the present invention with a catheter shaft  902  configured for retrograde deployment via femoral artery access. In order to facilitate placement of the aortic catheter  900  and to improve the stability of the catheter  900  in the proper position in the patient&#39;s aorta, a distal region  944  of the catheter shaft  902  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. The curved distal region  944  represents a J-shaped curve of approximately 180 degrees of arc with a radius of curvature of approximately 2 to 4 cm to match the typical curvature of the aortic arch in an adult human patient. In addition, the distal end  906  of the catheter may be skewed slightly up out of the plane of the curve to accommodate the forward angulation of the patient&#39;s ascending aorta. Additionally, the catheter shaft  902  may be reinforced, particularly in the curved distal region  944 , for example with braided or coiled wire, to further improve the stability of the catheter  900  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 10, is a magnified lateral cross section of the aortic catheter  900  of FIG. 9 taken along line  10 — 10  showing the multi-lumen arrangement of the catheter shaft  902 . The catheter shaft  902  has six lumens: a corporeal perfusion lumen  908 , an arch perfusion lumen  910 , a common balloon inflation lumen  912 , an arch monitoring lumen  914 , a guide wire and cardioplegia lumen  916  and a root pressure lumen  918 . 
     Referring to FIG. 9 the elongated catheter shaft  902  is preferably formed of a flexible thermoplastic material, a thermoplastic elastomer or a thermoset elastomer. The catheter shaft  902  may be fabricated separately by known extrusion methods and joined together end-to-end, for example by heat welding or by adhesive bonding. Alternatively, the catheter shaft  902  may be fabricated by dipping or by composite construction techniques and joined together or the entire catheter shaft  902  may be fabricated integrally. Suitable materials for the elongated catheter shaft  902  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. 
     An upstream occlusion member  920  is mounted on the catheter shaft  902  near the distal end  906  of the catheter  900 . The upstream occlusion member  920  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  902  by heat welding or with an adhesive. Suitable materials for the upstream occlusion member  920  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof. In addition, the outer surface of the upstream occlusion member  920  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. The upstream occlusion member  920  has a deflated state, in which the diameter of the occlusion member  920  is preferably not much larger than the diameter of the catheter shaft  902 , and an inflated state, in which the occlusion member  920  expands to a diameter sufficient to occlude blood flow in the ascending aorta of the patient. For use in adult human patients, the inflatable balloon upstream occlusion member  920  preferably has an inflated outer diameter of approximately 1.5 cm to 5.0 cm. Preferably, the inflatable occlusion member  920  has an inflated length that is not significantly longer than its inflated diameter, or, more preferably, is shorter than its inflated diameter. This shortened inflated profile allows the upstream occlusion member  920  to be easily placed within the ascending aorta between the coronary arteries and the brachiocephalic artery without any danger of inadvertently occluding either. 
     A downstream occlusion member  922  is mounted on the catheter shaft  902  at a position proximal to and spaced apart from the upstream occlusion member  920 . The distance between the upstream occlusion member  920  and the downstream occlusion member  922  is preferably between 3 and 20 cm, more preferably between 8 and 15 cm, and is chosen so that when the aortic catheter  900  is deployed and the upstream occlusion member  920  is positioned within the ascending aorta between the coronary arteries and the brachiocephalic artery, the downstream anchoring member  922  will be positioned in the descending aorta downstream of the left subclavian artery. The downstream occlusion member  922  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  902  by heat welding or with an adhesive. The downstream occlusion member  922  is may be larger, that is to say, more elongated, than the upstream occlusion member  920  of the same size or smaller. Suitable materials for the inflatable balloon downstream anchoring member  922  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof. In addition, the outer surface of the downstream anchoring member  922  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. 
     The inflatable downstream occlusion member  922  has a deflated state, in which the diameter of the occlusion member  922  is preferably not much larger than the diameter of the catheter shaft  902 , and an inflated state, in which the occlusion member  922  expands to a diameter sufficient to substantially prohibit blood flow in the descending aorta of the patient. For use in adult human patients, the downstream occlusion member  922  preferably has an inflated outer diameter of approximately 1.0 cm to 5.0 cm and a length of approximately 1.0 cm to 7.5 cm. The more elongated the occlusion member  922  the greater the anchoring friction against the wall of the descending aorta when the downstream occlusion member  922  is inflated in order to prevent migration of the aortic catheter  900  due to pressure gradients within the aorta during perfusion. 
     The corporeal perfusion lumen  908  extends through the catheter shaft  902  from the proximal end  904  to one or more corporeal perfusion ports  924  on the exterior of the catheter shaft  902  proximal of the downstream occlusion member  922 . Alternatively, to simplify catheter design and to reduce overall catheter diameter a separate contralateral, or co-lateral peripheral access arterial cannula may be used to access either the same femoral artery or the other femoral artery. The arch perfusion lumen  910  extends through the catheter shaft  902  from the proximal end  904  to one or more arch perfusion ports  926  on the exterior of the catheter shaft  902  between the upstream occlusion member  920  and the downstream occlusion member  922 . A common balloon inflation lumen  912  extends through the catheter shaft  902  from the proximal end  904  to balloon inflation ports  932  and  930  which reside in the interior of downstream occlusion balloon  922  and the upstream occlusion balloon  920  respectively. Alternatively, separate inflation lumens can be implemented to separately inflate the downstream occlusion member  922  and the upstream occlusion member  920 . 
     The arch monitoring lumen  914  extends through the catheter shaft  902  from the proximal end  904  to an arch monitoring port  934  proximal to the upstream occlusion member  920  to monitor pressure in the aortic root. The root pressure lumen  918  extends through the catheter shaft  902  from the proximal end  904  to a root pressure port  928  near the distal end  906  of the catheter shaft  902  to monitor pressure in the aortic root. The guide wire and cardioplegia lumen  916  extends from the proximal end  904  of the catheter shalt  902  to a guide wire/cardioplegia port  936  at the distal end  906  of the catheter shaft  902 , distal to the upstream occlusion member  920 . Preferably, the distal end  906  of the catheter shaft  902  is smoothly tapered or rounded for easy introduction and to avoid trauma or injury to the aortic wall during insertion or withdrawal of the aortic catheter  900 . 
     Preferably, the aortic catheter  900  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  900  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the aortic catheter  900  includes a distal radiopaque marker  938  positioned near the distal end  906  of the catheter shaft  902 , an intermediate radiopaque marker  940  positioned near the proximal edge of the upstream occlusion member  920 , and a proximal radiopaque marker  942  positioned near the distal edge of the downstream anchoring member  922 . Each of the radiopaque markers  938 ,  940 ,  942  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  904  of the catheter shaft  902  is connected to a manifold  950  with fittings for each of the catheter lumens. The corporeal perfusion lumen  908  is connected to a Y-fitting  962  that has a barb connector  952  for connection to a perfusion pump or the like and a luer connector  954 , which may be used for monitoring perfusion pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting. medications or other fluids. Likewise, the arch perfusion lumen  910  is connected to a Y-fitting  964  that has a barb connector  956  for connection to a perfusion pump and a luer connector  958  which may be used for monitoring arch perfusion pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting medications or other fluids. The common balloon inflation lumen  912  is connected to a stopcock or luer connector  960  or other fitting suitable for connection to a syringe or balloon inflation device. In addition the inflation lumen  912  may be attached to a pressure monitoring device to give visible and or tactile feedback concerning the balloon inflation pressure. The guide wire and cardioplegia lumen  916  is connected to a three-way Y-fitting  970  that has a barb connector  972  for connection to a cardioplegia infusion pump, a luer connector  974  capable of monitoring root perfusion pressure, temperature and chemical compositions and a guide wire port  976  with a Touhy-Borst adapter or other hemostasis valve. The root pressure lumen  918  is connected to a luer connector  968  or other suitable fitting capable of monitoring arch perfusion pressure, temperature and chemical compositions or for withdrawing fluid samples. The arch monitoring lumen  914  is connected to a luer connector  966  or other suitable fitting capable of monitoring arch perfusion pressure, temperature, and chemical compositions or for withdrawing fluid samples. Alternatively, sensors may be placed on the catheter shaft or inside the catheter shaft to measure chemical compositions in the aortic arch. 
     FIG. 11 illustrates a side view of a dual lumen venous drainage cannula  1199  of the present invention configured for introduction through the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities. Alternatively, the dual lumen venous drainage cannula  1199  may be configured for introduction though the patient&#39;s superior vena cava via the jugular vein or other suitable venous access point in the neck or upper extremities. The elongated tubular shaft  1198  may be fabricated separately by known extrusion methods and joined together end-to-end, for example by heat welding or by adhesive bonding. Alternatively, the elongated tubular shaft  1198  may be fabricated by dipping or by composite construction techniques and joined together or the entire tubular shaft  1198  may be fabricated integrally. Suitable materials for the elongated tubular shaft  1198  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. 
     FIG. 12 is a magnified lateral cross section of the venous drainage cannula  1199  taken along line  12 — 12  of FIG.  11 . FIG. 13 is a magnified lateral cross section of the venous drainage cannula  1199  taken along line  13 — 13  of FIG.  11 . Collectively FIGS. 11 through 13 illustrate the multi-lumen arrangement of the dual-lumen venous drainage cannula  1199  having an elongated tubular shaft  1198  which includes a first venous drainage,lumen  1188 ; a second venous drainage lumen  1189 ; a first balloon inflation lumen  1191 ,. and a second balloon inflation lumen  1194 . Alternatively, the dual-lumen venous drainage cannula  1199  may have a common balloon inflation lumen capable of simultaneously inflating both occlusion balloons. The tubular shaft  1198  preferably has a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). 
     The dual-lumen venous drainage cannula  1199  includes a first occlusion balloon  1197  or other expandable occlusion member mounted on the tubular shaft  1198 , which is positioned within the patient&#39;s superior vena cava when in,the operative position, and a second occlusion balloon  1196  or other expandable occlusion member, mounted on the tubular shaft  1198 , which is positioned within the patient&#39;s inferior vena cava when in the operative position. Suitable materials for the first occlusion member  1197  and the second occlusion member  1196  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof The occlusion balloons  1196  and  1197  preferably have an expanded diameter of approximately 5 mm to 40 mm. When the dual-lumen venous drainage cannula  1199  is configured for femoral artery introduction, the first occlusion balloon  1197  is mounted near the distal end  1195  of the tubular shaft  1198  and the second occlusion balloon  1196  is mounted somewhat proximal to the first balloon  1197 , as shown. Alternatiyely, for jugular vein introduction, these positions are reversed. 
     A first balloon inflation lumen  1191  is connected to a stopcock  1190  that extends through the tubular shaft  1198  to a balloon inflation port  1192  within the first occlusion balloon  1197 . The second balloon inflation lumen  1194 , is connected to a stopcock  1193 , that extends through the tubular shaft  1198  to a balloon inflation port  1123  within the second occlusion balloon  1196 . Alternatively, a common balloon inflation lumen may be implemented and a superior vena cava monitoring lumen may be implemented to monitor pressure, temperature and chemical composition in the superior vena cava. 
     The first venous drainage lumen  1188  extends from a venous drainage fitting  1187  through the tubular shaft  1198 , to one or more superior vena cava drainage ports  1195  on the tubular shaft  1198  distal to the first occlusion balloon  1197 . In addition, venous drainage ports  1182  which are distal to the second occlusion balloon  1196  are also in fluid communication with the first venous drainage lumen  1188 . Alternatively, the venous drainage ports  1182  may be in fluid communication with the second venous drainage lumen  1189 . The second venous drainage lumen  1189  extends from a venous drainage fitting  1181  through the tubular shaft  1198 , to one or more inferior vena cava drainage ports  1173  on the tubular shaft  1198  proximal to the second occlusion balloon  1196 . Preferably, the distal portion of the tubular shaft  1198  is smoothly tapered or rounded for easy introduction and to avoid trauma or injury to the vena cava during insertion or withdrawal of the venous cannula  1199 . 
     Preferably, the venous cannula includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the venous cannula  1199  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the venous drainage cannula  1199  includes a distal radiopaque marker  1178  positioned near the distal end  1195  of the tubular shaft  1198 , an intermediate radiopaque marker  1177  positioned near the drainage ports  1182 , and a proximal radiopaque marker  1176  positioned near the distal edge of the second occlusion member  1196 . Each of the radiopaque markers  1178 ,  1177 ,  1176  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  1183  of the venous drainage cannula  1199  is connected to a manifold  1125  with fittings for each of the catheter lumens. The first venous drainage lumen  1188  is coupled to a three-way fitting  1187  that has a barb connector  1186  for connection to an external CPB machine, a luer connector  1185  capable of monitoring superior vena cava pressure, temperature and chemical compositions and a guide wire port  1184  with a Touhy-Borst adapter or other hemostasis valve on the proximal end of the cannula  1183 . The second venous drainage lumen  1189  is coupled to a Y-fitting  1181  having a barb connector  1180 , or other suitable fitting capable of being coupled to a CPB machine and a luer fitting  1179  capable of monitoring inferior vena cava pressure, temperature and chemical compositions. A first inflation lumen  1191  is coupled to a stopcock  1190 , or other suitable fitting capable of being attached to an inflation mechanism and a second inflation lumen  1194  is coupled to a stopcock  1193 , or other suitable fitting capable of being attached to an inflation mechanism. In addition, each inflation lumen may have an individual pressure-monitoring device proximal or distal to the stopcock to provide visible and tactile feedback concerning the balloon inflation pressures. Alternatively, a common inflation lumen may be implemented. 
     FIG. 14 illustrates the second embodiment of the closed loop circulatory system of the present invention. FIG. 15 is a cutaway close-up view of the cannula placement as shown in FIG. 14 with a portion of the patient&#39;s heart cut away to better show the descending aorta. The cerebral loop of the circulatory support system is created by having venous drainage ports  1495  and  1482  in fluid communication with the superior vena cava drainage lumen  1488 . Coupled to the superior vena cava drainage lumen  1488  is a fitting  1487  having a barb connector  1486  coupled to tubing  1449  in fluid communication with an inflow port  1448  of a first blood circulation pump  1447 . The blood is conditioned and pumped through the outflow port  1446  of the first blood circulation pump  1447  to the arch perfusion lumen  1410  of the arterial cannula  1400 . The first blood circulation pump  1447  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the cerebral loop of the circulatory support system will also include a venous blood reservoir  1401 , a blood oxygenator  1403  and heat exchanger  1402  in series with the first blood circulation pump  1447 . Optionally, vacuum assist may be used to enhance venous drainage through the first venous drainage lumen  1488  of the dual-lumen venous drainage cannula  1499 . Venous blood from the head and upper extremities enters the patient&#39;s superior vena cava and is drained out through the first venous drainage lumen  1488  of the dual-lumen venous drainage cannula  1499  as the first occlusion balloon  1497  prevents blood from traveling into the right atrium from the superior vena cava. The blood is oxygenated, cooled and recirculated by the first blood circulation pump  1447  to the head and upper extremities through the arch perfusion lumen  1410  of the arterial cannula  1400 . 
     The corporeal loop of the circulatory support system is created by having a venous drainage port  1478  in fluid communication with inferior vena cava drainage lumen  1489 . A second Coupled to the second venous drainage lumen  1489  is a fitting  1481  having a barb connector  1480  coupled to tubing  1477  in fluid communication with an inflow port  1451  of a second blood circulation pump  1455 . After the blood is conditioned it is pumped through outflow port  1457  in fluid communication with tubing  1459  which is coupled to a barb connector  1452  in fluid communication the corporeal lumen  1408  of the aortic catheter  1400 . The second blood circulation pump may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the corporeal loop of the circulatory support system will also include a venous blood reservoir  1404 , a blood oxygenator  1406  and heat exchangerl 4 o 5  in series with the second blood circulation pump  1455 . Optionally, vacuum assist may be used to enhance venous drainage through the second venous drainage lumen of the dual-lumen venous drainage cannula  1400 . Venous blood from the viscera and lower extremities enters the patient&#39;s inferior vena cava and is drained out through the second venous drainage lumen  1489  of the dual-lumen venous drainage cannula  1499 . The blood is oxygenated, cooled and recirculated by the second blood circulation pump  1455  to the viscera and lower extremities through the corporeal perfusion lumen  1408  of the arterial catheter  1400 . 
     Optionally, the dual-lumen venous drainage cannula  1499  may be made without either the first occlusion balloon or the second occlusion balloon or one of the balloons may be partially deflated or completely deflated when operating in this mode since isolation of the patient&#39;s right atrium and the coronary sinus is unnecessary. Alternatively, the dual-lumen venous drainage cannula  1499  may be provided with a third venous drainage lumen within the tubular shaft connected to the drainage ports  1482  between the first and second balloons for draining the patient&#39;s right atrium and the coronary sinus. A separate coronary perfusion loop can be created by connecting the third venous drainage lumen to the inflow of a third blood circulation pump and connecting the outflow of the pump to the cardioplegia lumen of the arterial cannula  1400 . The third blood circulation pump may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the coronary loop also includes a venous blood reservoir, a blood oxygenator and heat exchanger in series with the third blood circulation pump. 
     As another alternative, the coronary circulation can be isolated by inserting a coronary sinus catheter via the jugular vein to isolate the coronary circulation on the venous side and for antegrade or retrograde flow of blood, cardioplegia or other fluids into the patient&#39;s coronary arteries. The first occlusion balloon  1495  could be eliminated from the dual-lumen venous drainage cannula  1499  or left uninflated so that the patient&#39;s right atrium will be drained as part of the cerebral loop. 
     FIGS. 16 through 23 collectively illustrate a third embodiment of the circulatory support system of the present invention, which is also configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. As in the previously described embodiment, the patient&#39;s coronary circulation may optionally be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created through the use of a separate coronary sinus catheter or through a separate pump. In this third embodiment of the circulatory support system, arterial cannulation is provided by a coaxial dual-balloon, selective arterial perfusion cannula  1600  and venous cannulation is provided by a coaxial dual-lumen venous drainage cannula  1799 . 
     FIG. 16 illustrates a side view of the aortic catheter  1600  according to the present invention with a coaxial catheter shaft  1602  configured for retrograde deployment via femoral artery access. Alternatively, a separate contralateral or colateral arterial cannula may be provided to provide perfusion to the corporeal body through separate cannulation of the a second peripheral artery. In order to facilitate placement of the aortic catheter  1600  and to improve the stability of the catheter  1600  in the proper position in the patient&#39;s aorta, a distal region  1644  of the catheter shaft  1602  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. The curved distal region  1644  represents a J-shaped curve of approximately  180  degrees of arc with a radius of curvature of approximately 2 to 4 cm to match the typical curvature of the aortic arch in an adult human patient. In addition, the distal end  1606  of the catheter may be skewed slightly up out of the plane of the curve to accommodate the forward angulation of the patient&#39;s ascending aorta. Additionally, the catheter shaft  1602  may be reinforced, particularly in the curved distal region  1644 , for example with braided or coiled wire, to further improve the stability of the catheter  900  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 17, is a magnified lateral cross section of the aortic catheter  1600  of FIG. 16 taken along line  17 — 17  showing the multi-lumen coaxial arrangement of the catheter shaft  1602 . The catheter shaft  1602  has six lumens: a corporeal perfusion lumen  1608 ; an arch perfusion lumen  1610 ; a common balloon inflation lumen  1612 ; an arch monitoring lumen  1614 ; a guide wire and cardioplegia lumen  1616  and a root pressure lumen  1618 . 
     FIG. 18 is a magnified lateral cross-section of the aortic catheter  1600  of FIG. 16 taken along line  18 — 18  showing the multi-lumen arrangement of the catheter shaft  1602 . Shown in FIG. 18, five of the six lumens continue distally through the catheter shaft  1602 : the arch perfusion lumen  1610 ; the common balloon inflation lumen  1612 ; the arch monitoring lumen  1614 ; the guide wire and cardioplegia lumen  1616  and the root pressure lumen  1618 . The corporeal perfusion lumen terminates at a position distal to the corporeal perfusion ports  1624 . 
     Referring to FIGS. 16 through 18 the elongated catheter is comprised of an inner tubular shaft and an outer tubular shaft configured in a coaxial relationship such that an annular space is created therebetween. The annular space between the tubular shafts  1603  and  1606  defines the corporeal lumen  1608 . The tubular shafts  1603  and  1606  are preferably formed of a flexible thermoplastic material, a thermoplastic elastomer or a thermoset elastomer. The coaxial catheter shaft  1602  may be fabricated separately by known extrusion methods and joined together end-to-end, for example by heat welding or by adhesive bonding. Alternatively, the coaxial catheter shaft  1602  may be fabricated by dipping or by composite construction techniques and joined together or the entire catheter shaft  1602  may be fabricated integrally. Suitable materials for the elongated catheter shaft  1602  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. 
     An upstream occlusion member  1620  is mounted on the inner tubular shaft  1603  near the distal end  1606  of the catheter  1600 . The upstream occlusion member  1620  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  1602  by heat welding or with an adhesive. Suitable materials for the upstream occlusion member  1620  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof In addition, the outer surface of the upstream occlusion member  1620  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. The upstream occlusion member  1620  has a deflated state, in which the diameter of the occlusion member  1620  is preferably not much larger than the diameter of the catheter shaft  1602 , and an inflated state, in which the occlusion member  1620  expands to a diameter sufficient to occlude blood flow in the ascending aorta of the patient. For use in adult human patients, the inflatable balloon upstream occlusion member  1620  preferably has an inflated outer diameter of approximately 1.5 cm to 5.0 cm. Preferably, the inflatable occlusion member  1620  has an inflated length that is not significantly longer than its inflated diameter, or, more preferably, is shorter than its inflated diameter. This shortened inflated profile allows the upstream occlusion member  1620  to be easily placed within the ascending aorta between the coronary arteries and the brachiocephalic artery without any danger of inadvertently occluding either. 
     A downstream occlusion member  1622  is mounted on the catheter shaft  1602  at a position proximal to and spaced apart from the upstream occlusion member  1620 . The distance between the upstream occlusion member  1620  and the downstream occlusion member  1622  is preferably between 3 and 20 cm, more preferably between 8 and 15 cm, and is chosen so that when the aortic catheter  1600  is deployed and the upstream occlusion member  1620  is positioned within the ascending aorta between the coronary arteries and the brachiocephalic artery, the downstream anchoring member  1622  will be positioned in the descending aorta downstream of the left subclavian artery. The downstream occlusion member  1622  in this embodiment is in the form of an expandable, inflatable balloon bonded to the catheter shaft  1602  by heat welding or with an adhesive. Suitable materials for the inflatable balloon downstream anchoring member  1622  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof In addition, the outer surface of the downstream anchoring member  1622  may include a friction increasing coating or texture to increase friction with the aortic wall when deployed. 
     The inflatable downstream occlusion member  1622  has a deflated state, in which the diameter of the occlusion member  1622  is preferably not much larger than the diameter of the catheter shaft  1602 , and an inflated state, in which the occlusion member  1622  expands to a diameter capable of regulating blood flow in the descending aorta of the patient. Therefore, to gain desired results the downstream occlusion member may be completely inflated, or partially inflated. For use in adult human patients, the downstream occlusion member  1622  preferably has an inflated outer diameter of approximately 1.0 cm to 5.0 cm and a length of approximately 1.0 cm to 7.5 cm. 
     The corporeal perfision lumen  1608  extends through the catheter shaft  1602  from the proximal end  1604  to one or more corporeal perfusion ports  1624  on the exterior of the catheter shaft  1602  proximal of the downstream occlusion member  1622 . The arch perfusion lumen  1610  extends through the catheter shaft  1602  from the proximal end  1604  to one or more arch perfusion ports  1626  on the exterior of the catheter shaft  1602  between the upstream occlusion member  1620  and the downstream occlusion member  1622 . A common balloon inflation lumen  1612  extends through the catheter shaft  1602  from the proximal end  1604  to balloon inflation ports  1632  and  1630  which reside in the interior of downstream occlusion balloon  1622  and the upstream occlusion balloon  1620  respectively. Alternatively, separate inflation lumens can be implemented to separately inflate the downstream occlusion member  1622  and the upstream occlusion member  1620 . 
     The arch monitoring lumen  1614  extends through the catheter shaft  1602  from the proximal end  1604  to an arch monitoring port  1634  proximal to the upstream occlusion member  1620  to monitor pressure in the aortic arch though the lumen  1614  or by providing a separate sensor slidably disposed in the lumen  1614 . The root pressure lumen  1618  extends through the catheter shaft  1602  from the proximal end  1604  to a root pressure port  1628  near the distal end  1606  of the catheter shaft  1602  to monitor pressure in the aortic root through the lumen  1618  or through a separate sensor slidably disposed in the lumen  1618 . The guide wire and cardioplegia lumen  1616  extends from the proximal end  904  of the catheter shaft  1602  to a guide wire/cardioplegia port  1636  at the distal end  1606  of the catheter shaft  1602 , distal to the upstream occlusion member  1620 . Preferably, the distal end  1606  of the catheter shaft  1602  is smoothly tapered or rounded for easy introduction and to avoid trauma or injury to the aortic wall during insertion or withdrawal of the aortic catheter  1600 . 
     Preferably, the aortic catheter  1600  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  900  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the aortic catheter  1600  includes a distal radiopaque marker  1638  positioned near the distal end  1606  of the catheter shaft  1602 , an intermediate radiopaque marker  1640  positioned near the proximal edge of the upstream occlusion member  1620 , and a proximal radiopaque marker  1642  positioned near the distal edge of the downstream anchoring member  1622 . Each of the radiopaque markers  1638 ,  1640 ,  1642  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  1604  of the catheter shaft  1602  is connected to a manifold  1650  with fittings for each of the catheter lumens. The corporeal perfusion lumen  1608  is connected to a Y-fitting  1662  that has a barb connector  1652  for connection to a perfusion pump or the like and a luer connector  1654 , which may be used for monitoring perfusion pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting medications or other fluids. Likewise, the arch perfusion lumen  1610  is connected to a Y-fitting  1664  that has a barb connector  1656  for connection to a perfusion pump and a luer connector  1658  which may be used for monitoring arch perfusion pressure, temperature, chemical compositions and for withdrawing fluid samples or for injecting medications or other fluids. The common balloon inflation lumen  1612  is connected to a stopcock or luer connector  1660  or other fitting suitable for connection to a syringe or balloon inflation device. In addition the inflation lumen may have a pressure monitoring balloon proximal or distal to the stopcock or luer fitting to give visible and tactile feedback concerning the balloon inflation pressure. The guide wire and cardioplegia lumen  1616  is connected to a three-way Y-fitting  1670  that has a barb connector  1672  for connection to a cardioplegia infusion pump, a luer connector  1674  capable of monitoring root perfusion pressure, temperature and chemical compositions and a guide wire port  1676  with a Touhy-Borst adapter or other hemostasis valve. The root pressure lumen  1618  is connected to a luer connector  1668  or other fitting suitable capable of monitoring arch perfusion pressure, temperature and chemical compositions or for withdrawing fluid samples. The arch monitoring lumen  1614  is connected to a luer connector  1666  or other fitting suitable capable of monitoring arch perfusion pressure, temperature, chemical compositions or for withdrawing fluid samples. 
     FIG. 19 illustrates a side view of a coaxial dual lumen venous drainage cannula  1999  of the present invention configured for introduction through the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities. Alternatively, the coaxial dual lumen venous drainage cannula  1999  may be configured for introduction though the patient&#39;s superior vena cava via the jugular vein or other suitable venous access point in the neck or upper extremities. The elongated coaxial tubular shaft  1998  may be fabricated separately by known extrusion methods and joined together end-to-end, for example by heat welding or by adhesive bonding. Alternatively, the elongated coaxial tubular shaft  1998  may be fabricated by dipping or by composite construction techniques and joined together or the entire elongated coaxial tubular shaft  1998  may be fabricated integrally. Suitable materials for the elongated coaxial tubular shaft  1998  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. 
     FIG. 20 is a magnified lateral cross section of the coaxial dual lumen venous drainage cannula  1999  taken along line  20 — 20  of FIG.  19 . FIG. 21 is a magnified lateral cross section of the coaxial dual lumen venous drainage cannula  1999  taken along line  21 — 21  of FIG.  19 . Collectively FIGS. 19 through 21 illustrate the multi-lumen arrangement wherein the inner tubular shaft  1915  and an outer tubular shaft  1917  are configured in a coaxial relationship such that an annular space is created therebetween, which defines the corporeal venous drainage lumen  1989 . The venous coaxial multi-lumen drainage cannula  1900  is further comprised of a cerebral drainage lumen  1988 , which is defined by the internal diameter of the inner tubular shaft  1915 , a first balloon inflation lumen  1991 , and a second balloon inflation lumen  1994 . The tubular shaft  1998  preferably has a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). 
     The dual-lumen venous drainage cannula  1999  includes a first occlusion balloon  1997  or other expandable occlusion member, mounted on the tubular shaft  1998 , which is positioned within the patient&#39;s superior vena cava when in the operative position, and a second occlusion balloon  1996  or other expandable occlusion member, mounted on the tubular shaft  1998 , which is positioned within the patient&#39;s inferior vena cava when in the operative position to create a segmentation of venous blood flow in the superior and inferior vena cava. Suitable materials for the first occlusion member  1997  and the second occlusion member  1996  include flexible polymers and elastomers, which include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, latex, silicone, and alloys, copolymers and reinforced composites thereof The occlusion balloons  1996  and  1997  preferably have an expanded diameter of approximately 5 mm to 40 mm. When the coaxial dual-lumen venous drainage cannula  1999  is configured for femoral artery introduction, the first occlusion balloon  1997  is mounted near the distal end  1995  of the inner tubular shaft  1915  and the second occlusion balloon  1996  is mounted somewhat proximal to the first balloon  1997 , on the outer tubular shaft  1917 . Alternatively, for jugular vein introduction, the positions of the occlusion balloons are reversed. 
     A first balloon inflation lumen  1991  is connected to a stopcock  1990  that extends through the tubular shaft  1998  to a balloon inflation port  1992  within the first occlusion balloon  1997 . The second balloon inflation lumen  1994 , is connected to a stopcock  1993 , that extends through the tubular shaft  1998  to a balloon inflation port  1923  within the second occlusion balloon  1996 . 
     The cerebral venous drainage lumen  1988  extends from a proximal venous drainage fitting  1987  in fluid communication with an external CPB machine through the tubular shaft  1998 , to one or more superior vena cava drainage ports  1995  on the tubular shaft  1998  distal to the first occlusion balloon  1997 . In addition, venous drainage ports  1982  which are proximal to the first occlusion balloon  1997  are also in fluid communication with the first venous drainage lumen  1988 . Alternatively, the venous drainage ports  1982  may be in fluid communication with the corporeal venous drainage lumen  1989 . Alternatively, a separate lumen may be provided to completely isolate the myocardial circulation. The corporeal venous drainage lumen  1989  extends from a proximal venous drainage fitting  1981  in fluid communication with an external CPB machine through the tubular shaft  1998 , to one or more inferior vena cava drainage ports  1978  on the tubular shaft  1998  proximal to the second occlusion balloon  1996 . Preferably, the distal portion of the tubular shaft  1998  is smoothly tapered or rounded for easy introduction and to avoid trauma or injury to vena cava during insertion or withdrawal of the coaxial multi-lumen venous cannula  1999 . 
     Preferably, the coaxial multi-lumen venous cannula  1999  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the venous cannula  1999  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the multilumen coaxial venous drainage cannula  1999  includes a distal radiopaque marker  1908  positioned. near the distal end of the tubular shaft  1998 , an intermediate radiopaque marker  1977  positioned near the drainage ports  1982 , and a proximal radiopaque marker  1976  positioned near the distal edge of the second occlusion member  1996 . Each of the radiopaque markers  1908 ,  1977 ,  1976  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  1983  of the coaxial multi-lumen venous drainage cannula  1999  is capable of receiving the inner tubular member and creating a fluid tight seal through the Touhy-Borst adapter  1931  or other suitable hemostasis valve capable of receiving a second catheter instrument. The cerebral venous drainage lumen  1988  is coupled to a Y-fitting  1987  that has a barb connector  1986  for connection to an external CPB machine, a luer connector  1985  capable of monitoring superior vena cava pressure, temperature and chemical compositions. The corporeal venous drainage lumen  1989  is coupled to a three-way fitting  1981  having a barb connector  1980 , or other suitable fitting capable of being coupled to a CPB machine, a luer fitting  1979  capable of monitoring inferior vena cava pressure, temperature and chemical compositions and a guide wire port  1984  with a Touhy-Borst adapter  1931  or other hemostasis valve. A first inflation lumen  1991  is coupled to a stopcock  1990 , or other suitable fitting capable of being attached to an inflation mechanism and a second inflation lumen  1994  is coupled to a stopcock  1993 , or other suitable fitting capable of being attached to an inflation mechanism. In addition, each inflation lumen may have an individual pressure-monitoring device proximal or distal to the stopcock to provide visible and tactile feedback concerning the balloon inflation pressures. 
     FIG. 22 illustrates a third embodiment of the support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. As in the previously described embodiments, the patient&#39;s coronary circulation may optionally be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created. In this embodiment of the circulatory support system, arterial cannulation is provided by a dual-balloon, coaxial selective arterial perfusion cannula  2200  and venous cannulation is provided by a dual-lumen, coaxial venous drainage cannula  2299 . A cutaway close-up view of the cannula placement is shown in FIG. 23 with a portion of the patient&#39;s heart cut away to better show the descending aorta. 
     The dual-lumen, coaxial venous drainage cannula  2299  may be configured for introduction though the patient&#39;s inferior vena cava via the femoral vein or other suitable venous access point in the lower extremities, as shown, or, alternatively, it may configured for introduction through the patient&#39;s superior vena cava via the jugular vein or other suitable venous access point in the neck or upper extremities. The dual-lumen coaxial venous drainage cannula  2299  has an inner tubular shaft  2215  that includes a first venous drainage lumen  2288  for draining venous blood from the patient&#39;s superior vena cava and an outer, coaxial tubular shaft  2217  that includes a second, coaxial venous drainage lumen  2289  for draining venous blood from the patient&#39;s inferior vena cava. In addition, the inner tubular shaft  2215  includes a first balloon inflation lumen  2291  and the outer tubular shaft  2217  includes a second balloon inflation lumen  2294  for inflating the balloons to enable the segmentation of the vena cava to isolate the cerebra, corporeal and myocardial circulation. The inner and outer tubular shafts  2215  and  2217  preferably have a length of approximately 15 cm to 90 cm and the outer tubular shaft  2217  preferably has a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). A first occlusion balloon  2297  or other expandable occlusion member mounted near the distal end of the inner tubular shaft  2215  and a second occlusion balloon  2296  or other expandable occlusion member is mounted near the distal end of the outer tubular shaft  2217 . The occlusion balloons  2297  and  2296  or other expandable occlusion members preferably have an expanded diameter of approximately 5 mm to 40 mm. The inner tubular shaft  2215  is slidable within a hemostasis seal  2231  at the proximal end of the outer tubular shaft  2217 . This allows adjustment of the distance between the first occlusion balloon  2297  and second occlusion balloon  2296  so that the first occlusion balloon  2297  can be positioned within the patient&#39;s superior vena cava, and the second occlusion balloon  2296  can be positioned within the patient&#39;s inferior vena cava. Preferably, the hemostasis seal includes a Touhy-Borst fitting or other compression seal that allows the user to selectively lock the relative position of the inner  2215  and outer  2217  tubular shafts. Optionally, a sliding hemostasis seal may be used at the distal end of the outer tubular shaft to seal the annular space between the inner and outer tubular shafts. 
     The superior vena cava drainage lumen  2288  extends through the inner tubular shaft  2215  from a first venous drainage fitting  2287  on the proximal end of the inner tubular shaft  2215  to one or more superior vena cava drainage ports  2295  on the inner tubular shaft  2215  distal to the first occlusion balloon  2297 . The superior vena cava drainage lumen  2288  may also connect to a distal guidewire port on the end of the inner tubular shaft  2215  distal to the first occlusion balloon  2297 . The second venous drainage lumen  2289  extends through the tubular shaft  2298  within the annular space from a second venous drainage fitting  2281  on the proximal end of the outer tubular shaft  2217  to one or more inferior vena cava drainage ports  2278  on the outer tubular shaft proximal to the second occlusion balloon  2296 . In addition, extra drainage can also be accomplished through an annular opening  2273 , and extra venous drainage ports  2282  distal to the second occlusion balloon  2296 . 
     The cerebral loop of the circulatory support system is created by connecting the superior vena cava venous drainage lumen  2288  of the inner tubular shaft  2215  to the inflow  2248  of a first blood circulation pump  2247  using suitable blood flow tubing  2249 , then connecting the outflow  2246  of the first blood circulation pump  2247  to the arch perfusion lumen  2210  of the arterial cannula  2200 . The first blood circulation pump  2247  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the cerebral loop of the circulatory support system will also include a venous blood reservoir  2201 , a blood oxygenator  2203  and heat exchanger  2202  in series with the first blood circulation pump  2247 . Optionally, vacuum assist may be used to enhance venous drainage through the first venous drainage lumen  2288  of the inner tubular shaft  2215 . Venous blood from the head and upper extremities is partitioned into the superior vena cava lumen  2288  by the first occlusion balloon  2297  and is drained out through the superior vena cava venous drainage lumen  2288  of the inner tubular shaft  2215 . The blood is oxygenated, cooled and recirculated by the first blood circulation pump  2247  to the head and upper extremities through the arch perfusion lumen  2210  of the arterial cannula  2200 . 
     The corporeal loop of the circulatory support system is created by connecting the inferior vena cava venous drainage lumen  2289  of the outer tubular shaft  2217  to the inflow  2251  of a second blood circulation pump  2255  using suitable blood flow tubing  2277 , then connecting the outflow of the second blood circulation pump  2255  to the corporeal perfusion lumen  2208  of the arterial cannula  2200 . The second blood circulation pump  2255  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the corporeal loop of the circulatory support system will also include a venous blood reservoir  2204 , a blood oxygenator  2206  and heat exchanger  2205  in series with the second blood circulation pump  2255 . Optionally, vacuum assist may be used to enhance venous drainage through the inferior vena cava venous drainage lumen  2289  of the tubular shaft  2298 . Venous blood from the viscera and lower extremities enters the patient&#39;s inferior vena cava and is partitioned into the inferior vena cava venous drainage lumen  2289  by the second occlusion balloon  2296  and is drained out through the inferior vena cava venous drainage lumen  2289 . The blood is oxygenated, cooled and recirculated by the second blood circulation pump  2255  to the viscera and lower extremities through the corporeal perfusion lumen  2208  of the arterial cannula  2200 . 
     The dual-lumen, coaxial venous drainage cannula  2299  also includes one or more drainage ports  2282  connected with the first venous drainage lumen  2288  on the inner tubular shaft  2215  between the first and second balloons  2297  and  2296  for draining the patient&#39;s right atrium and the coronary sinus as part of the cerebral loop. Alternatively, the patient&#39;s right atrium and the coronary sinus may be drained into the inferior vena cava venous drainage lumen  2289  through the annular space  2273  between the inner  2215  and outer  2217  tubular shafts as part of the corporeal loop. Optionally, the dual-lumen, coaxial venous drainage cannula  2299  may be made without either the first occlusion balloon  2297  or the second occlusion balloon  2296  or one of the balloons may be deflated when isolation of the patient&#39;s right atrium and the coronary sinus is not needed. Alternatively, the dual-lumen, coaxial venous drainage cannula  2299  may be provided with a third venous drainage lumen within the inner or outer tubular shaft connected to drainage ports between the first  2297  and second  2296  balloons for draining the patient&#39;s right atrium and the coronary sinus. A separate coronary perfusion loop can be created by connecting the third venous drainage lumen to the inflow of a third blood circulation pump and connecting the outflow of the pump to the cardioplegia lumen  2216  of the arterial cannula  2200 . The third blood circulation pump may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the coronary loop also includes a venous blood reservoir, a blood oxygenator and heat exchanger in series with the third blood circulation pump. 
     FIGS. 24 though  29  collectively illustrate a fourth embodiment of the circulatory support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. Optionally, the patient&#39;s coronary circulation may be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created. In this illustrative embodiment, arterial cannulation is provided by a low profile peripheral arterial cannulation subsystem that includes an aortic arch perfusion cannula  2400  and a separate corporeal perfusion cannula  2401 . Venous cannulation may be provided by any of previously described venous cannulae, for illustrative purposes, a superior vena cava cannula  399  as described in FIGS. 3 and 4 is used in conjunction with a separate inferior vena cava cannula  589  which was also fully described in FIGS. 5 and 6, there descriptions are incorporated by reference herein. The use of a low profile peripheral arterial cannulation subsystem with separate superior and inferior vena cava cannulae allows easier cannulation of patients with smaller peripheral arteries, such as pediatric patients and smaller adults, particularly women. The low profile peripheral arterial cannulation subsystem also allows percutaneous cannulation, without an arterial cutdown, in adult patients with normal sized peripheral arteries. 
     FIG. 24 illustrates an aortic arch perfusion cannula of the present invention configured for introduction into the aortic arch through peripheral arterial access in one of the upper extremities, such as the left or right subclavian artery, axillary artery or brachial artery. Alternatively, a two catheter arterial system may also be accomplished by cannulating both femoral arteries in a contralateral approach, or by cannulating the same femoral artery with the second arterial cannula in a collateral approach. The aortic arch perfusion cannula  2400  has a tubular shaft  2402  preferably having a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). In order to facilitate placement of the aortic arch catheter  2400  and to improve the stability of the catheter  2400  in the proper position in the patient&#39;s aorta, a distal region  2444  of the catheter shaft  2402  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. The curved distal region  2444  represents an S-shaped curve to match the typical curvature of the aortic arch in an adult human patient. In addition, the distal end  2406  of the catheter may be skewed slightly up out of the plane of the curve to accommodate the forward angulation of the patient&#39;s ascending aorta. Additionally, the catheter shaft  2402  may be reinforced, particularly in the curved distal region  2444 , for example with braided or coiled wire, to further improve the stability of the catheter  2400  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 25, is a magnified lateral cross section of the aortic arch perfusion cannula  2400  of FIG. 24 taken along line  25 — 25  of FIG. 24 showing the multi-lumen arrangement of the catheter shaft  2402 . The cannula shaft  2402  has four lumens including, an arch perfusion lumen  2410 , a balloon inflation lumen  2412 , a cardioplegia lumen  2416  and, a root pressure lumen  2418 . 
     Referring collectively to FIGS. 24 and 25, an occlusion balloon  2420  or other expandable occlusion member is mounted near the distal end  2406  of the tubular shaft  2402  so that it will be positioned in the ascending aorta between the coronary arteries and the right brachiocephalic artery, when the balloon  2420  is deployed. The arch perfusion lumen  2410  extends through the tubular shaft  2402  from an arch perfusion fitting  2464  on the proximal end of the cannula  2400  to one or more arch perfusion ports  2426  on the tubular shaft  2402  proximal to the occlusion balloon  2420 . The cardioplegia lumen  2416  extends through the tubular shaft  2402  from a cardioplegia fitting  2470  on the proximal end of the cannula  2400  to one or more cardioplegia ports  2436  on the tubular shaft  2402  distal to the occlusion balloon  2420 . The cardioplegia lumen  2416  may also serve as a guide wire lumen. In these alternative embodiments a Touhy-Borst fitting  2476  is in fluid communication with the cardioplegia lumen  2416  and is sized and dimensioned for receiving a guide wire to aid in the insertion and placement of the cannula  2400 . A root pressure lumen  2418  extends through the tubular shaft  2402  from a root pressure fitting  2468  on the proximal end of the catheter  2402  to one or more pressure ports  2428  on the tubular shaft  2402  distal to the occlusion balloon  2420 . The balloon inflation lumen  2412  extends through the tubular shaft  2402  from a balloon inflation fitting  2460  on the proximal end of the cannula  2400  to a balloon inflation port  2430  within the occlusion balloon  2420 . In addition, a separate arch monitoring lumen may be incorporated to allow the monitoring of pressure in the aortic arch proximal to the occlusion balloon  2420 . Alternatively, the arch monitoring lumen may be sized and configured to slidably receive an arch monitoring sensor to be inserted therethrough to take measurements in the arch. 
     Preferably, the aortic arch catheter  2400  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic arch catheter  2400  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the aortic arch catheter  2400  includes a distal radiopaque marker  2438  positioned near the distal end  2406  of the catheter shaft  2402 , an intermediate radiopaque marker  2440  positioned near the proximal edge of the occlusion member  2420 . Each of the radiopaque markers  2438  and  2440  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  2404  of the aortic arch catheter shaft  2402  is connected to a manifold  2450  with fittings for each of the catheter lumens. The arch perfusion lumen  2410  is connected to a Y-fitting  2464  that has a barb connector  2456  for connection to a perfusion pump and a luer connector  2458 . The balloon inflation lumen  2412  is connected to a stopcock  2460  or other fittings suitable for connection to a syringe or balloon inflation device. The guide wire and cardioplegia lumen  2416  is connected to a three-way Y-fitting  2470  that has a barb connector  2472  for connection to a cardioplegia infusion pump, a luer connector  2474  and a guide wire port  2476  with a Touhy-Borst adapter or other hemostasis valve. The root pressure lumen  2418  is connected to a luer connector  2468  or other fitting suitable for connection to a pressure monitor. 
     FIG. 26 illustrates a corporeal perfusion cannula of the present invention configured for introduction into the descending aorta through a peripheral arterial access in one of the lower extremities, such as the femoral artery. The corporeal perfusion cannula  2601  has a tubular shaft  2625  preferably having a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). The catheter shaft  2602  may be reinforced, for example with braided or coiled wire, to further improve the stability of the catheter  2600  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 27 is a magnified lateral cross section of the corporeal perfusion cannula  2601  taken along line  27 — 27  of FIG. 26 showing the multi-lumen arrangement of the catheter shaft  2689 . The tubular shaft  2625  has four lumens including; a corporeal perfusion lumen  2608 , a balloon inflation lumen  2614 , a guide wire lumen  2616  and an arch monitoring lumen  2619 . 
     Referring collectively to FIGS. 26 and 27, an occlusion balloon  2622  or other expandable occlusion member is mounted near the distal end of the tubular shaft  2625 . The corporeal perfusion lumen  2608  extends through the tubular shaft  2625  from a corporeal perfusion fitting  2662  on the proximal end of the cannula  2604  to one or more corporeal perfusion ports  2624  on the tubular shaft  2625  proximal to the occlusion balloon  2622 . The guide wire lumen  2616  extends through the tubular shaft  2625  from a guide wire fitting  2633  on the proximal end  2604  of the cannula  2600  to a guide wire port  2637  on the tubular shaft  2625  distal to the occlusion balloon  2622 . The balloon inflation lumen  2614  extends through the tubular shaft  2625  from a balloon inflation fitting  2666  on the proximal end  2604  of the cannula  2600  to a balloon inflation port  2632  within the occlusion balloon  2622 . A corporeal pressure monitoring lumen  2619  extends through the tubular shaft  2625  from a pressure monitoring fitting  2639  on the proximal end  2604  of the cannula  2600  to a corporeal pressure port  2607  on the tubular shaft  2625  proximal to the occlusion balloon  2622 . 
     Preferably, the corporeal catheter  2601  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  100  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). In this illustrative embodiment, the corporeal catheter  2601  includes a distal radiopaque marker  2638  positioned near the distal end  2606  of the catheter shaft  2625 , an intermediate radiopaque marker  2640  positioned near the proximal edge of the occlusion member  2622 , and a proximal radiopaque marker  2640  positioned near the distal edge of the anchoring member  2622 . Each of the radiopaque markers  2638  and  2640  may be made of a ring of dense radiopaque metal, such as gold, platinum, tantalum, tungsten or alloys thereof, or a ring of a polymer or adhesive material heavily loaded with a radiopaque filler material. 
     The proximal end  2604  of the catheter shaft  2625  is connected to a manifold  2650  with fittings for each of the catheter lumens. The corporeal perfusion lumen  2608  is connected to a Y-fitting  2662  that has a barb connector  2652  for connection to a perfusion pump or the like and a luer connector  2654 , which may be used for monitoring perfusion pressure, for withdrawing fluid samples or for injecting medications or other fluids. The balloon inflation lumen  2614  is connected to a stopcock connector  2666  or other fitting suitable for connection to a syringe or balloon inflation device. The guide wire lumen  2616  is connected to a Touhy-Borst adapter  2633  or other hemostasis valve. The corporeal pressure lumen  2619  is connected to a luer connector  2639  or other fitting suitable for connection to a pressure monitor. 
     FIG. 28 illustrates the circulatory support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. The cerebral loop of the circulatory support system is created by connecting the venous drainage lumen  2897  of the superior vena cava cannula  2899  to the inflow  2848  of a first blood circulation pump  2847  using suitable blood flow tubing  2849 , then connecting the outflow  2846  of the first blood circulation pump  2847  to the arch perfusion lumen  2810  of the arch perfusion cannula  2800 . The first blood circulation pump  2847  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the cerebral loop of the circulatory support system will also include a venous blood reservoir  2822 , a blood oxygenator  2802  and heat exchanger  2803  in series with the first blood circulation pump. Optionally, vacuum assist may be used to enhance venous drainage through the superior vena cava cannula  2899 . Venous blood from the head and upper extremities enters the patient&#39;s superior vena cava and is drained out through the venous drainage lumen  2897  of the superior vena cava cannula  2899 . The blood is oxygenated, cooled and recirculated by the first blood circulation pump  2847  to the head and upper extremities through the arch perfusion lumen  2810  of the arch perfusion cannula  2800 . 
     The corporeal loop of the circulatory support system is created by connecting the venous drainage lumen  2887  of the inferior vena cava cannula  2889  to the inflow  2851  of a second blood circulation pump  2855  using suitable blood flow tubing  2877 , then connecting the outflow  2857  of the second blood circulation pump  2855  to the corporeal perfusion lumen  2808  of the corporeal perfusion cannula  2801 . The second blood circulation pump  2855  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the corporeal loop of the circulatory support system will also include a venous blood reservoir  2804 , a blood oxygenator  2806  and heat exchanger  2805  in series with the second blood circulation pump. Optionally, vacuum assist may be used to enhance venous drainage through the inferior vena cava cannula  2889 . Venous blood from the viscera and lower extremities enters the patient&#39;s inferior vena cava and is drained out through the venous drainage lumen  2887  of the inferior vena cava cannula  2889 . The blood is oxygenated, cooled or warmed and recirculated by the second blood circulation pump  2855  to the viscera and lower extremities through the corporeal perfusion lumen  2808  of the corporeal perfusion cannula  2801 . 
     FIGS. 29 through 35 collectively illustrate a fifth embodiment of the circulatory support system of the present invention configured for selective, isolated, dual-loop perfusion of a patient&#39;s circulatory system. This embodiment of the circulatory support system is configured for central venous and central arterial cannulation using open-chest:,or minimally-invasive surgical techniques, for example by insertion through a minithoracotomy, partial sternotomy, median sternotomy or thorocotomy. The circulatory support system has a cerebral loop for perfusion of the patient&#39;s cerebral circulation and upper extremities and a separate corporeal loop for perfusion of the patient&#39;s viscera and lower extremities. Optionally, the patient&#39;s coronary circulation may be included in the cerebral loop or the corporeal loop or a third, isolated coronary loop may be created. In this embodiment of the circulatory support system, arterial cannulation is provided by a dual-balloon, selective, central arterial perfusion cannula  2900 , and venous cannulation is provided by a central superior vena cava cannula  3199  and a separate central inferior vena cava cannula  3189 . 
     FIG. 29 illustrates a side view of the dual-balloon, selective, central arterial perfusion cannula  2900  is configured for antegrade introduction into the patient&#39;s aortic arch via a direct puncture or incision in. the ascending aorta. Because the aortic catheter  2900 . is introduced directly into the ascending aorta, the elongated catheter shaft  2902  has an overall length of approximately 20 to 60 cm. In order to facilitate placement of the aortic catheter  2900  and to improve the stability of the catheter  2900  in the proper position in the patient&#39;s aorta, a distal region  2944  of the catheter shaft  2902  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. The curved distal region  2944  represents an S-shaped curve with a primary curve  2946  of approximately 180 degrees of arc with a radius of curvature of approximately 2 to 4 cm to match the typical curvature of the aortic arch in an adult human patient and a secondary curve  2948  that is a bend of approximately 90 degrees or more where the catheter shaft  2902  will pass through the aortic wall. Additionally, the catheter shaft  2902  may be reinforced, particularly in the curved distal region  2944 , for example with braided or coiled wire, to further improve the stability of the catheter  2900  in the proper position in the patient&#39;s aorta. 
     Illustrated in FIG. 30 is a magnified lateral cross section of the aortic catheter  2900  of FIG. 29 taken along line  30 — 30  in FIG. 29 illustrating the multi-lumen arrangement of the aortic catheter  2900 . The catheter shaft  2902  has six lumens: a guide wire and corporeal perfusion lumen  2908 , an arch perfusion lumen  2910 , an arch monitoring lumen  2912 , a balloon inflation lumen  2914 , a cardioplegia lumen  2916  and a root pressure lumen  2918 . The elongated catheter shaft  2902  has an outer diameter which is preferably from approximately 9 to 30 French (3.0-10.0 mm diameter), more preferably from approximately 12 to 18 French (4.0-6.0 mm diameter) for adult human patients. Additionally, the aortic catheter  2900  includes a distal radiopaque marker  2938  positioned near the distal end  2906  of the catheter shaft  2902 , an intermediate radiopaque marker  2940  positioned near the proximal edge of the downstream anchoring member  2922 , and a proximal radiopaque marker  2942  positioned near the distal edge of the upstream occlusion member  2920 . 
     A downstream occlusion member  2922 , in the form of an inflatable balloon, is mounted on the catheter shaft  2902  near the distal end  2906  of the catheter shaft  2902 . When placed in the operative position, the downstream occlusion member  2922  may be partially inflated or completely inflated to a diameter sufficient to regulate blood flow in the descending aorta. For use in adult human patients, the downstream occlusion member  2922  preferably has an inflated outer diameter of approximately 0.5 cm to 4.0 cm and a length of approximately 1.0 cm to 7.5 cm. An upstream occlusion member  2920 , in the form of an expandable, inflatable balloon, is mounted on the catheter shaft  2902  at a position proximal to and spaced apart from the downstream anchoring member  2922  so that it is positioned in the ascending aorta when deployed. The distance between the upstream occlusion member  2920  and the downstream occlusion member  2922  is preferably between 3 and 20 cm, more preferably between 8 and 15 cm, and is chosen so that, when the aortic catheter  2900  is deployed and the upstream occlusion member  2920  is positioned within the ascending aorta between the coronary arteries and the brachiocephalic artery, the downstream occlusion member  2922  will be positioned in the descending aorta downstream of the left subclavian artery. When inflated, the upstream occlusion member  2920  expands to a diameter sufficient to occlude blood flow in the ascending aorta. For use in adult human patients, the inflatable balloon upstream occlusion member  2920  preferably has an inflated outer diameter of approximately 1.5 cm to 4.0 cm. Preferably, the inflatable balloon upstream occlusion member  2920  has an inflated length that is not significantly longer than its inflated diameter, or, more preferably, is shorter than its inflated diameter to allow the upstream occlusion member  2920  to be easily placed within the ascending aorta between the coronary arteries and the brachiocephalic artery without any danger of inadvertently occluding either. 
     The arch perfusion lumen  2910  extends through the catheter shaft  2902  from the proximal end  2904  to one or more arch perfusion ports  2926  on the exterior of the catheter shaft  2902  between the upstream occlusion member  2920  and the downstream anchoring member  2922 . The arch monitoring lumen  2912  extends through the catheter shaft  2902  from the proximal end to an arch monitoring port  2928  located between the upstream occlusion member  2920  and the downstream anchoring member  2922  to monitor pressure in the aortic arch. The root pressure lumen  2918  extends through the catheter shaft  2902  from the proximal end  2904  to a root pressure port  2921  located distal to the downstream anchoring member  2922  to monitor pressure in the aortic root. The common balloon inflation lumen  2914  extends through the catheter shaft  2902  from the proximal end  2904  to balloon inflation ports  2930 ,  2932  within the upstream occlusion member  2920  and the downstream anchoring member  2922 , respectively. Alternatively, separate inflation lumens may be provided for independently inflating the upstream occlusion member  2920  and the downstream anchoring member  2922 . The guide wire and corporeal perfusion lumen  2908  extends from the proximal end  2904  of the catheter shaft  2902  to one or more corporeal perfusion ports  2924  and a guide wire port  2936  at the distal end  2906 , distal to the downstream anchoring member  2922 . The cardioplegia lumen  2916  extends from the proximal end  2904  of the catheter shaft  2902  to a cardioplegia port  2966  proximal to the upstream occlusion member  2920 . Alternatively, when a cardioplegia lumen  2926  is not included a separate cardioplegia needle or catheter may be used to infuse cardioplegia fluid into the aortic root upstream of the upstream of the occlusion member  2920 . 
     The proximal end  2904  of the catheter shaft  2902  is connected to a manifold  2950  with fittings for each of the catheter lumens. The arch perfusion lumen  2910  is connected to a Y-fitting  2964  that has a barb connector  2956  for connection to a perfusion pump or the like and a luer connector  2958 , which may be used for monitoring perfusion pressure, for withdrawing fluid samples or for injecting medications or other fluids. 
     The arch monitoring lumen  2912  is connected to a luer connector  2960  or other fitting suitable for connection to a pressure monitor. The balloon inflation lumen  2914  is connected to a luer connector  2966  or other fitting suitable for connection to a syringe or balloon inflation device. The guide wire and corporeal perfusion lumen  2908  is connected to a three-way Y-fitting  2970  that has a barb connector  2972  for connection to a perfusion pump, a luer connector  2974  and a guide wire port  2976  with a Touhy-Borst adapter or other hemostasis valve. The cardioplegia lumen  2916  is connected to a Y-fitting  2971  having a barb connector  2973  for connection to a cardioplegia source, and a luer connector  2977 . 
     FIG. 31 illustrates a side view of the central superior vena cava cannula  3199  of the present invention configured for introduction into the patient&#39;s superior vena cava via an incision in the right atrium. FIG. 32 is a magnified lateral cross-section of the central superior vena cava cannula  3199  taken along line  32 — 32  of FIG.  31 . The central superior vena cava cannula  3199  has a tubular shaft  3198  that includes a venous drainage lumen  3197  and a balloon inflation lumen  3196 . The tubular shaft preferably has a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). Suitable materials for the elongated tubular shaft  3198  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. In addition, the tubular shaft  3198  may be preformed to better facilitate ease of entry into the superior vena cava from a right atrium entry site. 
     An occlusion balloon  3195  or other expandable occlusion member is mounted on the tubular shaft  3198  near the distal end  3179  of the cannula  3199 . The occlusion balloon  3195  or other expandable occlusion member preferably has an expanded diameter of approximately 5 mm to 40 mm. The venous drainage lumen  3197  extends through the tubular shaft  3198  from a venous drainage fitting  3194  on the proximal end of the cannula  3199  to one or more venous drainage ports  3193  on the tubular shaft  3198  distal to the occlusion balloon  3195 . The venous drainage lumen  3197  may also serve as a guide wire lumen having a proximal Touhy-Borst fitting  3192 , or other hemostasis valve capable of creating a fluid tight seal around a guide wire and guiding catheter, to a guide wire port  3179  on the distal end  3176  of the tubular shaft  3198  distal to the occlusion balloon  3195 . In addition, the proximal venous drainage fitting  3194  has a barb connector  3178  or other suitable fitting capable of being coupled to a CPB machine and a luer fitting  3175  capable of withdrawing fluid samples in the superior vena cava. The balloon inflation lumen  3196  extends through the tubular shaft  3198  from a balloon inflation fitting  3191  on the proximal end of the catheter  3199  to one or more balloon inflation ports  3190  within the occlusion balloon. 
     FIG. 33 illustrates a side view of the central inferior vena cava cannula  3389  of the present invention configured for introduction into the patient&#39;s inferior vena cava through the same or another incision in the right atrium. FIG. 34 is a magnified lateral cross-section of the central superior vena cava cannula  3389  taken along line  33 — 33  of FIG.  33 . The central inferior vena cava cannula  3389  has a tubular shaft  3188  that includes a venous drainage lumen  3387  and a balloon inflation lumen  3386 . The tubular shaft preferably has a length of approximately 15 cm to 90 cm and a diameter of approximately 10 to 32 French (3.3 mm to 10.7 mm diameter). Suitable materials for the elongated tubular shaft  3188  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, silicone, latex, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. In addition, the tubular shaft  3388  may be preformed to better facilitate ease of entry into the inferior vena cava from a right atrium entry site. 
     An occlusion balloon  3385  or other expandable occlusion member is mounted on the tubular shaft  3388  near the distal end  3366  of the cannula  3389 . The occlusion balloon  3385  or other expandable occlusion member preferably has an expanded diameter of approximately 5 mm to 40 mm. The venous drainage lumen  3387  extends through the tubular shaft  3388  from a venous drainage fitting  3384  on the proximal end of the cannula  3389  to one or more venous drainage ports  3383  on the tubular shaft  3388  distal to the occlusion balloon  3385 . The venous drainage lumen  3387  may also serve as a guide wire lumen having a proximal Touhy-Borst fitting  3382 , or other hemostasis valve capable of creating a fluid tight seal around a guide wire and guiding catheter, to a guide wire port  3369  on the distal end  3366  of the tubular shaft  3388  distal to the occlusion balloon  3385 . In addition, the proximal venous drainage fitting  3384  has a barb connector  3365  or other suitable fitting capable of being coupled to a CPB machine and a luer fitting  3367  capable of withdrawing fluid samples in the inferior vena cava. The balloon inflation lumen  3386  extends through the tubular shaft  3388  from a balloon inflation fitting  3381  on the proximal end of the catheter  3389  to one or more balloon inflation ports  3380  within the occlusion balloon. 
     FIG. 35 is a schematic diagram of a fifth embodiment of the circulatory support system of the present invention configured for selective, isolated, dual loop perfusion of a patient&#39;s circulatory system. The cerebral loop is created by connecting the venous drainage lumen  3597  of the central superior vena cava cannula  3599  to the inflow  3548  of a first blood circulation pump  3547  using suitable blood flow tubing  3549 , then connecting the outflow  3546  of the first blood circulation pump  3547  to the arch perfusion lumen  3510  of the central arterial perfusion cannula  3500 . The first blood circulation pump  3547  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the cerebral loop of the circulatory support system will also include a venous blood reservoir, a blood oxygenator and heat exchanger in series with the first blood circulation pump. Optionally, vacuum assist may be used to enhance venous drainage through the central superior vena cava cannula  3599 . Venous blood from the head and upper extremities enters the patient&#39;s superior vena cava and is drained out through the venous drainage lumen  3597  of the central superior vena cava cannula  3599 . The blood is oxygenated, cooled and recirculated by the first blood circulation pump  3547  to the head and upper extremities through the arch perfusion lumen  3510  of the central arterial perfusion cannula  3599 . The corporeal circulation is prevented from mixing with the cerebral circulation on the venous side by the occlusion balloons  3595  on the superior vena cava cannula  3599  and  3585  on the inferior vena cava cannula  3589 . Mixing is prevented in the arterial circulation by upstream occlusion member  3520  and downstream occlusion member  3522 . 
     The corporeal loop of the circulatory support system is created by connecting the venous drainage lumen  3587  of the central inferior vena cava cannula  3589  to the inflow  3551  of a second blood circulation pump  3555  using suitable blood flow tubing  3544 , then connecting the outflow  3557  of the second blood circulation pump  3555  to the corporeal perfusion lumen  3508  of the central arterial perfusion cannula  3500 . The second blood circulation pump  3555  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the corporeal loop of the circulatory support system will also include a venous blood reservoir, a blood oxygenator and heat exchanger in series with the second blood circulation pump  3555 . Optionally, vacuum assist may be used to enhance venous drainage through the central inferior vena cava cannula  540 . Venous blood from the viscera and lower extremities enters the patient&#39;s inferior vena cava and is drained out through the venous drainage lumen  3587  of the central inferior vena cava cannula  3589 . The blood is oxygenated, cooled and recirculated by the second blood circulation pump  3555  to the viscera and lower extremities through the corporeal perfusion lumen  3508  of the central arterial perfusion cannula  3500 . 
     Optionally, the patient&#39;s right atrium and the coronary sinus may be drained through one or more drainage ports  3522  on the central inferior vena cava cannula  3589  or on the tubular shaft of the central superior vena cava cannula  3599  proximal to the cannula&#39;s occlusion balloon  3595 . Alternatively, the patient&#39;s right atrium and the coronary sinus may be drained into a cardiotomy reservoir using a separate suction cannula. As another alternative, the coronary circulation can be isolated by inserting a coronary sinus catheter  3525  through the same or another incision in the right atrium to isolate the coronary circulation on the venous side and for antegrade or retrograde flow of blood, cardioplegia or other fluids into the patient&#39;s coronary arteries. The coronary sinus catheter  3525  will have a an occlusion balloon to seal the coronary sinus. Fluid may be perfused in the antegrade direction or fluid may be vacuumed through the coronary sinus catheter in the retrograde direction. The proximal end of the coronary sinus catheter  3525  is coupled to tubing  3523  in fluid communication with a separate pump system including a reservoir  3516  a pump  3540  a cardioplegia, or drug delivery source  3519 , a heat exchanger  3533  and an oxygenator  212 . The blood, cardioplegia, or drug delivery fluid is conditioned and pumped through tubing  3532  coupled to barb connector  3573  in fluid communication with cardioplegia lumen  3516  and distal fluid port  3517 . The system creates a retrograde delivery subcirculation or antegrade subcirculation depending upon the rotation of the pump  3540 . Alternatively a perfusion pump may be used if total isolation of the coronary circulation is not necessary which would allow mixing of fluid in the venous system. 
     In another aspect of the present invention, the circulatory support system can be configured for selective, closed-loop perfusion of an isolated organ system within the patient&#39;s body while the beating heart supplies the remainder of the circulatory system. In effect, this creates an isolated, dual-loop perfusion system with the patient&#39;s heart performing the function of the second blood circulation pump. A perfusion shunt device is used to allow the patient&#39;s heart to continue beating, while isolating a selected organ system within the body. Suitable perfusion shunt devices for this application are described in detail in commonly owned, copending patent application U.S. Ser. No. 09/212,5880, filed Dec. 14, 1998 by Macoviak et al., which is hereby incorporated by reference in its entirety. 
     FIGS. 36 through 38 show a sixth embodiment of the circulatory support system configured for selective, closed-loop perfusion of an isolated organ system within the patient&#39;s body while the beating heart supplies the remainder of the circulatory system. FIG. 36 is a side view of the aortic perfusion shunt apparatus  3600  configured for insertion into a patient&#39;s aorta via a peripheral artery such as the femoral artery. FIG. 37 is a distal end view of the expanded shunt device  3602  illustrating a shunt conduit  3612  of the aortic perfusion shunt apparatus  3600  of FIG. 36 taken along line  37 — 37 . 
     Referring now to FIG. 36, the expandable shunt device  3602  is mounted on an elongated catheter shaft  3620  for introduction into the patient&#39;s circulatory system. In this exemplary embodiment of the perfusion shunt apparatus  3600  the elongated catheter shaft  3620  is configured for retrograde deployment of the expandable shunt conduit  3602  in a patient&#39;s aortic arch via a peripheral arterial access point, such as the femoral artery. Alternatively, it may be adapted for antegrade deployment via direct aortic insertion. The elongated catheter shaft  3620  should have a length sufficient to reach from the arterial access point where it is inserted into the patient to the aortic arch. For femoral artery deployrnent, the elongated catheter shaft  3620  preferably has a length from approximately 60 to 120 cm, more preferably 70 to 90 cm. The elongated catheter shaft  3620  is preferably extruded of a flexible thermoplastic material or a thermoplastic elastomer. Suitable materials for the elongated catheter shaft  3620  include, but are not limited to, polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides (nylons), polyesters, and alloys or copolymers thereof, as well as braided, coiled or counterwound wire or filament reinforced composites. Optionally, the distal end of the catheter shaft  3620  may be preshaped with a curve to match the internal curvature of the patient&#39;s aortic arch. 
     Referring now to FIGS. 36 and 37, the elongated catheter shaft  3620  has an arch perfusion lumen  3610 , a common inflation lumen  3688 , an arch monitoring lumen  3611 , a guide wire lumen  3615  and a root pressure lumen  3618 . The arch perfusion lumen  3610  extends through the catheter shaft  3620  from the proximal end  3604  to one or more arch perfusion ports  3626  on the exterior of the catheter shaft  3620  between the upstream sealing member  3608  and the downstream sealing member  3607 . The arch monitoring lumen  3611  extends through the catheter shaft  3620  from the proximal end  3604  to an arch monitoring port  3628  located between the upstream sealing mechanism  3608  and the downstream sealing mechanism  3607  to monitor pressure in the aortic arch. The root pressure lumen  3618  extends through the catheter shaft  3620  from the proximal end  3604  to a root pressure port  3601  located distal to the downstream sealing mechanism  3608  to monitor pressure in the aortic root. The common balloon inflation lumen  3688  extends through the catheter shaft  3620  from the proximal end  3604  to balloon inflation ports  3614  within the upstream sealing mechanism  3608  and the downstream sealing mechanism  3607 , respectively. Alternatively, separate inflation lumens may be provided for independently inflating the upstream sealing mechanism  3608  and the downstream sealing mechanism  3607 . The guide wire lumen  3615  extends from the proximal end  3604  of the catheter shaft  3620  to a guide wire port  3616  at the distal end  3606 , of the catheter shaft  3620 . 
     The proximal end  3604  of the catheter shaft  3620  is connected to a manifold  3650  with fittings for each of the catheter lumens. The arch perfusion lumen  3610  is connected to a Y-fitting  3664  that has a barb connector  3656  for connection to a perfusion pump or the like and a luer connector  3658 , which may be used for monitoring perfusion pressure, for withdrawing fluid samples or for injecting medications or other fluids. The arch monitoring lumen  3611  is connected to a luer connector  3660  or other fitting suitable for connection to a pressure monitor. The balloon inflation lumen  3688  is connected to a luer connector  3666  or other fitting suitable for connection to a syringe or balloon inflation device. The guide wire lumen  3615  is connected to a guide wire port  3676  with a Touhy-Borst adapter or other hemostasis valve. The root pressure lumen  3618  is connected to a luer fitting  3672  or other suitable pressure fitting capable of being coupled to a pressure monitoring device. 
     Preferably, the perfusion shunt apparatus  3600  includes one or more markers, which may include radiopaque markers and/or sonoreflective markers, to enhance imaging of the perfusion shunt apparatus  3600  using fluoroscopy or ultrasound, such as transesophageal echocardiography (TEE). An upstream radiopaque and/or sonoreflective marker ring  3640  on the catheter shaft  3620  just proximal to the upstream sealing member  3608  and a second, downstream radiopaque and/or sonoreflective marker ring  3642  on the catheter shaft  2620  just distal to the downstream sealing member  3607 . Alternatively or additionally, radiopaque markers and/or sonoreflective markers may be placed on the sealing members  3607 ,  3608  and/or the shunt conduit  3602  to show the position and/or the deployment state of the perfusion shunt apparatus  3600 . 
     FIG. 38 shows a schematic diagram of a sixth embodiment of the circulatory support system of the present invention configured for selective, closed-loop perfusion of a patient&#39;s cerebral circulation and upper extremities, while the beating heart supplies the viscera and lower extremities with blood. In this embodiment of the circulatory support system, the aortic arch vessels are isolated using perfusion shunt apparatus  3800  and venous cannulation is provided by a superior vena cava cannula  3899  similar to the one previously described in connection with FIGS. 3 and 4, although any of the previously described venous cannula systems may be implemented. 
     Referring to FIG. 38, the arch perfusion shunt apparatus  3800  has an expandable shunt device  3802  mounted on an elongated catheter shaft  3820 . The expandable shunt device  3802  has an expandable shunt conduit  3812  an upstream sealing member  3808  at the upstream end of the device  3802  and a downstream sealing member  3807  at the downstream end of the device  3802 . The upstream and downstream sealing members  3808 ,  3807  may be inflatable, toroidal balloons, as illustrated, or external flow control valves may be used. A common inflation lumen  3888  or alternatively, separate inflation lumens (not shown) extend through the catheter shaft  3820  from one or more inflation fittings  3866  on the proximal end  3804  of the catheter shaft  3820  to inflation ports  3814  within the upstream occlusion member  3808  and the downstream occlusion member  3807 . The expandable shunt conduit  3802  is inserted into the patient&#39;s aorta in a collapsed state and is expanded within the aortic arch when the inflated upstream sealing member  3808  is positioned between the aortic valve and the brachiocephalic artery and the inflated downstream sealing member  3807  positioned downstream of the left subclavian artery creating a fluid channel shunt conduit  3812 . An arch perfusion lumen  3810 , within the catheter shaft  3820 , extends from a perfusion fitting  3864  at the proximal end  3804  of the catheter shaft  3820  to one or more arch perfusion ports  3826  within the annular chamber  3819  surrounding the shunt conduit  3802 . 
     The cerebral loop of the circulatory support system is created by connecting the venous drainage lumen  3897  of the superior vena cava cannula  3899  to the inflow  3851  of a first blood circulation pump  3857  using suitable blood flow tubing  3877 , then connecting the outflow  3853  of the first blood circulation pump  3857  to the arch perfusion lumen  3810  of the arch perfusion shunt apparatus  3800 . The first blood circulation pump  3857  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the cerebral loop of the circulatory support system will also include a venous blood reservoir, a blood oxygenator and heat exchanger in series with the first blood circulation pump  3857 . Optionally, vacuum assist may be used to enhance venous drainage through the superior vena cava cannula  3899 . Venous blood from the head and upper extremities enters the patient&#39;s superior vena cava and is drained out through the venous drainage lumen  3897  of the superior vena cava cannula  3899 . The blood is oxygenated, cooled and recirculated by the first blood circulation pump  3857  to the head and upper extremities through the arch perfusion lumen  3810  of the arch perfusion shunt apparatus  3800 . 
     In this embodiment of the invention, the corporeal loop of the circulatory system is supplied by the patient&#39;s beating heart. Oxygenated blood from the heart passes through the expandable shunt conduit  3812  of the shunt device  3802 , thus bypassing the aortic arch vessels. From there, the blood flows through the descending aorta to the viscera and the lower extremities in the usual manner, returning to the heart via the inferior vena cava. The corporeal circulation is prevented from mixing with the cerebral circulation on the venous side by the occlusion balloon  3895  on the superior vena cava cannula  3899 . 
     Perfusion shunt devices can also be used to isolate other organ systems within a patient&#39;s body, such as the renal system or hepatic system. A selective, closed-loop perfusion system can be created for these organ systems by using an arterial perfusion shunt apparatus and a venous perfusion shunt apparatus connected to a blood circulation pump. 
     FIG. 39 shows a schematic diagram of a seventh embodiment of the circulatory support system of the present invention configured for selective, closed-loop perfusion of a patient&#39;s renal system, while the beating heart supplies the remainder of the circulatory system with blood. An arterial perfusion shunt apparatus  3900  is placed in the descending aorta via the femoral artery so that the upstream sealing member  3908  and the downstream sealing member  3907  isolate the ostia of the renal arteries from the aortic lumen. A venous perfusion shunt device  3999  is placed in the inferior vena cava via the femoral vein so that the upstream sealing member  3995  and the downstream sealing member  3985  isolate the ostia of the renal veins from the lumen of the inferior vena cava. 
     A renal circulation loop is created within the circulatory support system by connecting the perfusion lumen  3987  of the venous perfusion shunt device  3999  to the inflow  3951  of a first blood circulation pump  3957  using suitable blood flow tubing  3977 , then connecting the outflow  3953  of the first blood circulation pump  3957  to the perfusion lumen  3910  of the arterial perfusion shunt device  3900 . The first blood circulation pump  3957  may be a peristaltic roller pump, a centrifugal blood pump or other suitable blood circulation pump. Preferably, the renal circulation loop of the circulatory support system will also include a venous blood reservoir  3904 , a blood oxygenator  3906  and heat exchanger  3905  in series with the first blood circulation pump  3957 . Optionally, vacuum assist may be used to enhance venous drainage through the venous perfusion shunt device  3999 . Venous blood from the renal arteries enters the annular chamber  3918  surrounding the shunt device  3922  and is drained out through the perfusion lumen  3987  in the catheter shaft  3920 . The blood is oxygenated, cooled and otherwise conditioned and recirculated by the first blood circulation pump  3957  to the renal arteries through the perfusion lumen  4010  of the arterial perfusion shunt device  3900 . Alternatively, the renal circulation loop or other isolated circulatory loop may be perfused in the retrograde direction. 
     The remainder of the circulatory system is supplied by the patient&#39;s beating heart. Oxygenated blood from the heart flowing through the descending aorta passes through the shunt conduit  3912  of the example shunt device  3932  of the arterial perfusion shunt apparatus  3900 , thus bypassing the renal arteries. From there, the blood flows through the abdominal descending aorta to the rest of the viscera and the lower extremities in the usual manner, returning to the heart via the inferior vena cava. Blood returning through the inferior vena cava passes through the lumen  3962  of the expandable shunt device  3922  of the venous prefusion shunt apparatus  3999 , and bypasses the isolated renal circulation. 
     While the present invention has been described herein with respect to the exemplary embodiments and the best mode for practicing the invention, it will be apparent to one of ordinary skill in the art that many modification, improvements and subcombinations of the various embodiments, adaptations and variations can be made to the invention without departing from the spirit and scope thereof. In addition, it can be easily understood by one of ordinary skill in the art that any combination of the venous cannulae and arterial cannulae as well as any insertion position can be used in combination to create the desired system for a surgical intervention, the invention being defined by the claims.