Abstract:
The present invention includes an apparatus and methods for differentially perfusing a patient undergoing cardiopulmonary bypass. A cardiopulmonary bypass machine is configured to provide hypothermic oxygenated blood and normothermic oxygenated blood to an aortic balloon catheter. The catheter has arch perfusion ports and corporeal perfusion ports and is introduced into a patient&#39;s aorta and navigated transluminally until the occlusion balloon is located in the descending aorta. The occlusion balloon is inflated and hypothermic oxygenated blood is perfused to the arch vessels while normothermic oxygenated blood is perfused to the corporeal circulation. This procedure offers the benefit of cerebral protection from embolic events during cardiopulmonary bypass surgery.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to medical devices and methods for performing cardiovascular, pulmonary and neurological procedures and more particularly to aortic catheter devices for cardiopulmonary bypass support of a patient during surgical interventions.  
         BACKGROUND OF THE INVENTION  
         [0002]    Partial or full cardiopulmonary bypass (hereafter “CPB”) support is needed for medical procedures requiring general anesthesia where lung function is to be arrested during routine and high-risk cardiovascular, cardioneural and other surgical interventions including beating, fully arrested or partially arrested cardiac procedures, to maintain cardiovascular, cardioneural and corporeal support of the respective heart, cerebral and corporeal organ systems. Such surgical interventions include treatment of aneurysms, congenital valve disease, and coronary artery disease. Cardiac interventions such as angioplasty, atherectomy, thrombectomy, coronary bypass grafting, and heart valve repair or replacement are some of the other procedures that can be performed.  
           [0003]    In procedures where the heart is to be fully or partially arrested, it has been conventionally preferred that the heart and coronary vasculature be isolated from the rest of the cardiovascular system by application of an external cross clamp or side biting clamp. Isolation allows antegrade or retrograde perfusion of cold, warm or normothermic oxygenated blood cardioplegia or crystalloid cardioplegia to the coronary arteries to aid in the preservation of the myocardium and to prevent dispersion of cardioplegia to the rest of the body. The heart chambers may then be vented for decompression and to create a bloodless surgical field for intracardiac interventions. For rapid cooling and arrest of the myocardium in open-chest procedures, direct application of a topical ice slush or cold pericardial lavage into the thoracic space is performed simultaneously while the cold coronary perfusion process is being accomplished. While the heart is arrested, oxygenated blood is perfused to the rest of the body to maintain cerebral and corporeal support without perfusion to the coronary arteries, which could resuscitate the partially or fully arrested heart and obscure the surgical field with blood before completion of the surgical intervention.  
           [0004]    A preferred way to accomplish CPB is by inserting a venous cannula into a venous blood vessel, typically the vena cava, withdrawing deoxygenated blood and directing the fluid to a connected pump. The pump circulates the withdrawn blood through a blood oxygenator, heat exchanger and filter apparatus and then perfuses the oxygenated and temperature controlled blood and other fluids through an aortic perfusion catheter inserted into the aorta of the patient.  
           [0005]    Stroke and neurological deficit are well documented sequelae of the above cardiac surgery procedure. Recent literature has documented that the incidence of stroke is as high as 6.1% with an additional 30-79% of patients suffering from some form of cognitive deficit. Neurological deficit varies from patient to patient, however common injuries include: loss of memory, concentration, hand-eye coordination, and an increase in morbidity and mortality. The impact on the patient is significant, but factors such as age, the level of intellectual activity and the amount of physical activity pursued by the patient prior to surgery all affect the quality of life. Finally, patients who suffer from neurologic injury have a substantially prolonged hospital stay, with an attendant increase in cost (Neurological Effects of Cardiopulmonary Bypass; Rogers AT, Cardiopulmonary Bypass Principles and Practice; Gravlee GP, 21:542).  
           [0006]    One of the likely causes of stroke and neurological deficit is the release of emboli into the blood stream during heart surgery. Potential embolic materials include atherosclerotic plaques or calcific plaques from within the aorta or cardiac valves and thrombus or clots from within the chambers of the heart. These potential emboli may be dislodged during surgical manipulation of the heart and the ascending aorta or due to high velocity jetting (sometimes called the “sandblasting effect”) from the aortic perfusion cannula. In addition, application and release of an external cross clamp or side biting clamp has been shown to release emboli into the blood circulation. Other potential sources of emboli include gaseous microemboli formed when using a bubble oxygenator for CPB and “surgical air” that enters the heart chambers or the blood stream during surgery through open incisions or through the aortic perfusion cannula.  
           [0007]    The following Journal articles addressing specific problems associated with emboli are listed below:  
           [0008]    Journal Articles relating to Cerebral Embolization and Adverse Cerebral Outcomes After Cardiac Surgery: Determination or Size of Aortic Emboli and Embolic Load During Coronary Artery Bypass Grafting; Barbut et al.; Ann Thorac Surg 1997; 63:1262-7; Aortic Atheromatosis and Risks of Cerebral Embolization; Barbut et al.; J Card &amp; Vasc Anesth, Vol 10, No 1, 1996: pp 24-30. Aortic Atheroma is Related to Outcome but not Numbers of Emboli During Coronary Bypass; Barbut et al.; Ann Thorac Surg 1997, 64:454-9; Adverse Cerebral Outcomes After Coronary Artery Bypass Surgery; Roach et al.; New England J of Med, Vol 335, No 25, 1996: pp. 1857-1863; Signs of Brain Cell Injury During Open Heart Operations: Past and Present; Åberg; Ann Thorac Surg 1995, 59:1312-5; The Role of CPB Management in Neurobehavioral Outcomes After Cardiac Surgery; Murkin; Ann Thorac Surg 1995, 59:1308-11; Risk Factors for Cerebral Injury and Cardiac Surgery; Mills; Ann Thorac Surg 1995, 59:1296-9; Brain Microemboli Associated with Cardiopulmonary Bypass: A Histologic and Magnetic Resonance Imaging Study; Moody et al.; Ann Thorac Surg 1995, 59:1304-7; CNS Dysfunction After Cardiac Surgery: Defining the Problem; Murkin; Ann Thorac Surg 1995, 59:1287; Statement of Consensus on Assessment of Neurobehavioral Outcomes After Cardiac Surgery; Murkin et al.; Ann Thorac Surg 1995, 59:1289-95; Heart-Brain Interactions: Neurocardiology Comes of Age; Sherman et al.; Mayo Clin Proc 62:1158-1160, 1987; Cerebral Hemodynamics After Low-Flow Versus No-Flow Procedures; van der Linden; Ann Thorac Surg 1995, 59:1321-5; Predictors of Cognitive Decline After Cardiac Operation; Newman et al.; Ann Thorac Surg 1995, 59:1326-30. Cardiopulmonary Bypass: Perioperative Cerebral Blood Flow and Postoperative Cognitive Deficit; Venn et al.; Ann Thorac Surg 1995, 59:1331-5; Long-Term Neurologic Outcome After Cardiac Operation; Sotaniemi; Ann Thorac Surg 1995, 59:1336-9; Macroemboli and Microemboli During Cardiopulmonary Bypass; Blauth; Ann Thorac Surg 1995, 59:1300-3.  
           [0009]    Recently, there has been much development in the area of minimally invasive cardiac surgery (MICS) and the use of balloon catheters to address the clinical problems associated with a conventional median sternotomy and the attendant use of a cross clamp to occlude the ascending aorta. For example, U.S. Pat. No. Re 35,352 to Peters describes a single balloon catheter for occluding a patient&#39;s ascending aorta and a method for inducing cardioplegic arrest. A perfusion lumen or a contralateral arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. U.S. Pat. No. 5,584,803 to Stevens et al. describes a single balloon catheter for inducing cardioplegic arrest and a system for providing cardiopulmonary support during closed chest cardiac surgery. A coaxial arterial cannula is provided for supplying oxygenated blood during cardiopulmonary bypass. The occlusion balloon of these catheters must be very carefully placed in the ascending aorta between the coronary arteries and the brachiocephalic artery, therefore the position of the catheter must be continuously monitored to avoid complications.  
           [0010]    In clinical use, these single balloon catheters have shown a tendency to migrate in the direction of the pressure gradient within the aorta. More specifically, during infusion of cardioplegia, the balloon catheter will tend to migrate downstream due to the higher pressure on the upstream side of the balloon and, when the CPB pump is on, the balloon catheter with tend to migrate upstream into the aortic root due to the higher pressure on the downstream side of the balloon. This migration can be problematic if the balloon migrates far enough to occlude the brachiocephalic artery on the downstream side or the coronary arteries on the upstream side.  
           [0011]    Another important development in the area of aortic balloon catheters is the concept of selective aortic perfusion. Described in commonly owned U.S. Pat. Nos. 5,308,320, 5,383,854 and 5,820,593 by Peter Safar, S. William Stezoski, and Miroslav Klain is a double balloon catheter for segmenting a patient&#39;s aorta for selective perfusion of different organ systems within the body. Other U.S. patents which address the concept of selective aortic perfusion include; U.S. Pat. No. 5,738,649, by John A. Macoviak, U.S. Pat. Nos. 5,827,237 and 5,833,671 by John A. Macoviak and Michael Ross; and commonly owned, copending patent application Ser. No. 08/665,635, filed Jun. 18, 1996, by John A. Macoviak and Michael Ross. All the above listed patents and patent applications, as well as all other patents referred to herein, are hereby incorporated by reference in their entirety.  
           [0012]    Safar teaches the peripheral introduction of an aortic balloon catheter to establish CPB and to facilitate intravascular surgical interventions. Additionally, Safar teaches an apparatus and method of selective differential perfusion, which allows segmentation of the circulatory system into separate coronary, cerebral and corporeal subcirculations. The aortic balloon catheter allows establishment of CPB without the need for a thoracotomy, which may also facilitate minimally-invasive surgical procedures on the arrested heart. Although minimally-invasive techniques provide a beneficial alternative to the open chest median sternotomy, the present invention specifically addresses a method where a thoracotomy, such as a median sternotomy, is desirable because of the need for direct exposure of the heart and an apparatus specifically designed for such a purpose.  
           [0013]    U.S. Pat. No. 5,697,905 to d&#39;Ambrosio teaches a single balloon, triple lumen catheter to be positioned in the ascending aorta to reduce the release of embolized air and particulate matter into general body circulation. The aforementioned device uses a suction lumen to remove released emboli.  
           [0014]    The following U.S. patents relate to aortic filters associated with atherectomy devices in order to trap potential emboli before they are introduced into the general circulation: U.S. Pat. Nos. 5,662,671 and 5,769,816. The following international patent applications also relate to aortic filters and aortic filters associated with atherectomy devices: WO 97/17100, WO 97/42879, WO 98/02084.  
           [0015]    Catheters intended to occlude the descending aorta are disclosed by Manning, U.S. Pat. Nos. 5,678,570, 5,216,032, and Paradis, U.S. Pat. No. 5,334,142. However, none of the aforementioned devices were designed, nor intended, for use in the manner of the present invention.  
           [0016]    The previous inventions do not adequately address the patient population where a conventional median sternotomy and differential perfusion are desirable. Therefore, what has been needed and previously unavailable is an apparatus and system to selectively and differentially perfuse the cerebral sub-circulation with hypothermic oxygenated blood and perfuse the corporeal sub-circulation with normothermic oxygenated blood. The present invention solves this immediate problem, as well as others.  
         SUMMARY OF THE INVENTION  
         [0017]    In keeping with the foregoing discussion, it is a primary object of the present invention to provide a method and apparatus which is as familiar to physicians as possible, while at the same time introducing the concept of differential perfusion when a thoracotomy, such as a median sternotomy is implemented. Differential perfusion will enable the clinician to specifically determine flow, temperature and composition of perfusate delivered to the brain differentially from the body. Isolation of the cerebral circulation from the corporeal circulation facilitates the creation of a neuroprotective environment through temperature and chemical control, allowing the brain to be cooled to a significantly lower temperature than the body. Lowering the temperature of the brain results in a corresponding reduction of blood flow to the brain since the metabolic demands of the tissue for oxygen are reduced. This benefit allows for an overall reduction in flow, volume and cycles of blood to the brain and less opportunity for emboli to be introduced into the cerebral blood circulation during surgical interventions.  
           [0018]    In addition, prolonged hypothermia for the brain while the body is warm extends the neuroprotective period while avoiding issues associated with systemic hypothermia, such as coagulopathy, low cardiac output and prolonged Intensive Care Unit time. Furthermore, by keeping the heart relatively normothermic, the problem of cardiac arrythmias associated with hypothermia is better controlled.  
           [0019]    The invention contemplates the use of a cardiopulmonary bypass machine configured with two heat exchangers coupled to an aortic catheter with a flow control regulator mounted on the catheter shaft to at least partially occlude the descending aorta, while a standard cross clamp occludes the ascending aorta. The aortic catheter and flow control regulator used in concert will create a segmentation of the aorta allowing for differential perfusion of the arch circulation separate from the corporeal circulation. The heart is kept in an arrested state through hypothermia, hypothermic perfusion, or by injecting crystalloid cardioplegia, blood cardioplegia or any combination thereof into the coronary arteries of the heart.  
           [0020]    The differential perfusion system of the present invention includes a catheter with an elongated catheter shaft, an arch perfusion lumen connected to an arch perfusion port, a corporeal perfusion lumen connected to a corporeal perfusion port, and a flow control regulator positioned between the two ports. The shaft has a proximal portion that is composed of the corporeal lumen and the arch lumen extending in a coaxial relationship. The arch perfusion lumen terminates at a point along the catheter shaft and the corporeal lumen continues through the distal portion of the catheter shaft, terminating at the distal opening of the catheter shaft. The distal corporeal perfusion port, defined by the distal opening and accompanying corporeal ports, is in fluid communication with a proximal fitting that is connected to a cardiopulmonary bypass machine. The distal corporeal perfusion port is sized and dimensioned to provide optimal flow and pressure to the corporeal sub-circulation while minimizing the undesirable “sandblasting effect”.  
           [0021]    The internal arch perfusion lumen extends part way through the catheter shaft and terminates at a distal arch perfusion port. The proximal fitting of the arch perfusion lumen is connected to a cardiopulmonary bypass machine. The distal port is sized and dimensioned to provide optimal flow and pressure to the cerebral sub-circulation.  
           [0022]    A flow control regulator is located on the distal portion of the catheter shaft and resides between the corporeal perfusion port and the arch perfusion port. The flow control regulator may be in the form of an inflatable balloon or a selectively deployable valve. The design feature of having coaxial lumens allows for a smaller diameter distal portion and a smooth transition in diameter without sacrificing a consistent internal diameter for corporeal flow. Alternatively, the distal portion could remain the same size as the proximal portion, allowing for a larger internal diameter in the distal portion for corporeal flow.  
           [0023]    In use, the surgeon will typically place a purse string suture and aortotomy after which, the catheter tip is inserted into the ascending aorta. The distal tip of the catheter may be adapted to be used in conjunction with an internal stylet or trocar or may be preoperatively prepared in a cold saline solution to create a more rigid tip that becomes soft and flexible after insertion, thereby eliminating the need for a stylet or trocar.  
           [0024]    Once inserted, the distal tip is advanced transluminally in an antegrade direction through the vessel until the flow control regulator, is positioned in the descending aorta downstream of the left subclavian artery. Placement may be verified in a number of ways well known in the art such as transesophageal echography (TEE), X-ray fluoroscope or fiberoptic illumination. However, since the intraluminal distance to be covered is relatively short, 4-8 inches to travel downstream of the left subclavian artery after insertion, proper placement is easily verified by determining the amount of catheter shaft located within the vessel by reference to a suture ring located external to the catheter shaft. Furthermore, once the flow control regulator is placed in the proper position there is little concern that displacement will occur since the catheter shaft is rigid enough to resist undesired movement yet compliant enough to move through the vessel without damaging the interior vessel wall.  
           [0025]    After proper placement is verified, the surgeon generally begins CPB and starts perfusing the aorta prior to application of an external cross-clamp or internal cross-clamp to the ascending aorta. Once minimum proper perfusion flow has been established the surgeon will apply the cross-clamp to the aorta or inflate an occlusion balloon inside the aorta and supply crystalloid cardioplegia or blood cardioplegia to the myocardium to completely or partially arrest the heart. The flow control regulator is then activated, at least partially occluding the descending aorta downstream of the left subclavian artery, thereby creating a compartmentalization of the aorta. Upstream of the flow control regulator, hypothermic oxygenated blood is perfused to the arch vessels through the arch perfusion port. Downstream of the flow control regulator, normothermic oxygenated blood is perfused to the corporeal circulation through the corporeal perfusion port. For a description of a CPB machine that is specially configured with multiple heat exchangers and multiple pump heads to provide oxygenated blood to an aortic catheter with different temperatures, reference is made to commonly owned copending application Ser. No. 60/084,835 filed on Dec. 4, 1998, which is hereby incorporated by reference in its entirety. Upstream of the cross-clamp, antegrade or retrograde cardioplegia is supplied keeping the heart in a partially or completely arrested state.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]    [0026]FIG. 1 shows a perspective view of a first embodiment of the aortic catheter of the present invention configured for antegrade deployment via the ascending aorta.  
         [0027]    [0027]FIG. 2 is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along the line  2 - 2  in FIG. 1.  
         [0028]    [0028]FIG. 3 is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along the line  3 - 3  in FIG. 1.  
         [0029]    [0029]FIG. 4 is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along the line  4 - 4  in FIG. 1.  
         [0030]    [0030]FIG. 5 is a schematic diagram showing the aortic catheter of FIG. 1 deployed within a patient&#39;s aorta.  
         [0031]    [0031]FIG. 6 is a schematic diagram showing a second embodiment of the aortic catheter of the present invention with a passively activated peripheral flow control valve regulator  
         [0032]    [0032]FIGS. 7 and 8 illustrate a third embodiment of the aortic catheter of the present invention with an actively deployable peripheral flow control valve regulator and attached actuation wires.  
         [0033]    [0033]FIGS. 9 and 10 illustrate a fourth embodiment of the aortic catheter of the present invention with an actively deployable peripheral flow control valve regulator that is inflatable through an inflation lumen.  
         [0034]    [0034]FIGS. 11 and 12 illustrate a fifth embodiment of the aortic catheter of the present invention with an actively deployable peripheral flow control valve regulator that is actuated through an inflatable actuating balloon.  
         [0035]    [0035]FIG. 13 is a schematic diagram showing a sixth embodiment of the aortic catheter of the present invention having a selectively deployable central flow control valve regulator.  
         [0036]    [0036]FIGS. 14 through 16 illustrate a seventh embodiment of the aortic catheter of the present invention wherein the central flow control valve regulator is actively deployed by using a second catheter.  
         [0037]    [0037]FIGS. 17 and 18 are cutaway illustrations of an eighth embodiment of the present invention where the central flow control valve regulator is mechanically deployed by one or more actuation wires.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    [0038]FIGS. 1 through 3 illustrate a first embodiment of the aortic catheter  10  of the present invention, which is configured for antegrade deployment via the ascending aorta. FIG. 1 is a perspective view of the shaft portion of the aortic catheter  110 . FIG. 2 is a magnified lateral cross section of the aortic catheter  110  taken along the line  2 - 2  in FIG. 1. FIG. 3 is a magnified lateral cross section of the aortic catheter  110  taken along the line  3 - 3  in FIG. 1.  
         [0039]    Referring to FIG. 1 the aortic catheter  110  has an elongated shaft  111  with a proximal end  130  and a distal end  131 . The elongated catheter shaft  111  should be long enough to be inserted into the ascending aorta and guided transluminally in an antegrade direction such that the distal tip  120  and the flow control regulator  150  are positioned in the descending aorta. With the aforementioned requirements in mind, the overall length of the catheter shaft  111  is preferably between 4 and 30 cm, more preferably between 7 and 20 cm, most preferably between 12 and 15 cm.  
         [0040]    The aortic catheter  110  is preferably configured to provide differential flow, pressure, temperature and chemical composition. Although differential flow and pressure can be accomplished with a single blood flow lumen, by adding another lumen, either in a side-by-side arrangement or in a coaxial relationship, differential flow, temperature and chemical composition can be accomplished. In one embodiment, as exemplified in FIG. 1, the elongated shaft  111  has a proximal coaxial portion  102  and a distal portion  101 . As shown in FIG. 2, which is a magnified lateral cross-section of the aortic catheter  110  of FIG. 1 taken along the line  2 - 2 , the proximal coaxial portion  102  has three lumens: a corporeal perfusion lumen  133 , an arch perfusion lumen  135  and a flow control regulator lumen  140 .  
         [0041]    In a particularly preferred embodiment, the proximal portion  102  may be further described as having an inner coil reinforced shaft  132  and an outer  134  coil reinforced shaft configured in a co-axial relationship. The coil reinforced catheter shafts  132  and  134  may be made from any number of materials such as 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 coil reinforcement may be achieved by embedding, laminating, or coextruding flat wire, helically wound wire or braided wire on or into the shaft material. The inner coil reinforced shaft  132  and the outer coil reinforced shaft  134  are arranged in a coaxial relationship such that an annular space is created therebetween defining the arch perfusion lumen  135 . The corporeal perfusion lumen  133  is defined by the internal diameter of the inner coil reinforced shaft  132 . The proximal coaxial portion  102  of the shaft  111  terminates at one or more arch perfusion ports  116  in an unreinforced area along the length of the catheter shaft  111  proximal to the flow control regulator  150 . Alternatively, the arch perfusion ports  116  may be located in a coil reinforced area of the catheter shaft  111 . The termination position may vary, however arch anatomy is a primary consideration and the arch perfusion ports  116  are intended to be located near the arch vessels to enable optimum perfusion. The arch perfusion ports are sized and configured to provide optimal flow with a low peak velocity to limit the “sandblasting” effect in the aorta. In an exemplary embodiment there are 8 arch perfusion ports  116  residing around the exterior of the catheter shaft  111 . Alternatively, there may be more or less perfusion ports depending upon lumen size and kink resistance in the aortic shaft.  
         [0042]    As shown in FIG. 3, which is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along line  3 - 3 , the corporeal perfusion lumen  133  and the flow control regulator lumen  140  continue distally to form the distal portion  101  of the catheter shaft  111 . The distal portion  101  of the catheter shaft  111  preferably has a length of 2-10 cm, more preferably 3-8 cm, most preferably 4-6 cm. The coaxial design allows for a smaller diameter distal portion  101 , relative to the diameter of the proximal portion  102 . Alternatively, the diameter of the distal portion  101  can be increased to allow for a larger perfusion lumen  33  without creating an overall increase in the diameter of the catheter  110 . In either case, optimal corporeal flow can be accomplished through the perfusion lumen  133 . Preferably, the catheter shaft  111  has an outer diameter that is from approximately 9 to 22 French (3.0-7.3 mm diameter), more preferably from approximately 12 to 18 French (4.0-6.0 mm diameter). Preferably, the distal portion  101  of the elongated catheter shaft  111  has a preformed 90-degree curvature specially designed to conform to the patient&#39;s aortic anatomy.  
         [0043]    As shown in FIG. 4, which is a magnified lateral cross section of the aortic catheter of FIG. 1 taken along line  4 - 4 , the corporeal perfusion lumen  133  terminates at the distal opening  112  of the elongated catheter shaft  111  as well as one or more corporeal perfusion ports  112  residing in the exterior of the insertion tip  120 . The corporeal perfusion ports  112  are sized and configured to perfuse blood at an optimal flow with a low peak velocity. The corporeal perfusion ports  112  surround the insertion tip  120  to ensure proper perfusion and even distribution of perfusates. In an exemplary embodiment, the number of corporeal perfusion ports  112  is 5, including the distal opening. Alternatively, there may be more or less corporeal perfusion ports  112  depending upon the material construction of insertion tip  120  and the size of the corporeal lumen  133 . The corporeal perfusion ports may reside in an unreinforced portion of the aortic catheter shaft  111  or in a reinforced portion of the aortic catheter shaft  111 .  
         [0044]    The coaxial relationship between the two shafts creates an annular space that represents the arch perfusion lumen  135 . The inner coil reinforced shaft  132  has an internal diameter that is preferably between 0.025″ and 0.300″, more preferably between 0.100″ and 0.225″, most preferably between 0.140″ and 0.185″. The outer coil reinforced shaft  134  has an internal diameter preferably between 0.150″ and 0.350″, more preferably between 0.200″ and 0.325″, most preferably between 0.225″ and 0.300″.  
         [0045]    The arch perfusion lumen  35  is preferably configured to provide a flow rate of 0.1 L/min to 3 L/min with a pressure drop between 0 mm Hg and 300 mm Hg, more preferably configured to provide 0.25 L/min to 2.5 L/min with a pressure drop between 0 mm Hg and 200 mm Hg, most preferably configured to provide 1 L/min to 2 L/min with a pressure drop between 0 mm Hg and 100 mm Hg.  
         [0046]    The corporeal lumen  33  is preferably configured to provide a flow rate of 0.5 L/min to 8 L/min with a pressure drop between 0 mm Hg and 300 mm Hg, more preferably configured to provide 2 L/min to 6 L/min with a pressure drop between 0 mm Hg and 200 mm Hg, most preferably configured to provide 3.00 L/min to 5.00 L/min with a pressure drop between 0 mm Hg and 100 mm Hg.  
         [0047]    The combined flow rate of the arch and corporeal perfusion lumens is preferably between 0.5 L/min and 10 L/min with a pressure drop between 0 mm Hg and 300 mm Hg, more preferably the flow rate is between 1 L/min and 9 L/min with a pressure drop between 0 mm Hg and 200 mm Hg, most preferably the flow rate is between 2 L/min and 8 L/min with a pressure drop between 0 mm Hg and 100 mm Hg.  
         [0048]    A flow control regulator  150  is located on the distal portion  101  of the catheter shaft  111  and is actuated through the actuation lumen  140  once proper placement in the descending aorta has been established. The flow control regulator  150  is designed to prohibit substantial fluid flow in the aorta however, direct engagement with the vessel wall may not always be necessary to accomplish desired results. Nevertheless, when engagement with the vessel wall does occur it is non-traumatic.  
         [0049]    The flow control regulator  150  in this particular embodiment is in the form of an expandable occlusion balloon, actuated through an inflation lumen  140 . The balloon is attached to the catheter shaft  111  by any number of known methods such as heat welding or adhesive bonding, for example ultraviolet activated adhesive. Suitable materials for the flow control regulator  150  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. Manufacturing techniques for making the balloons include dipping and or blow molding.  
         [0050]    The inflatable flow control regulator  150  has a deflated state, in which the diameter is preferably not much larger than the diameter of the catheter shaft  111 , and an inflated state, in which the flow control regulator  150  expands to a diameter sufficient to prohibit substantial blood flow in the descending aorta of the patient. For use in adult human patients, the flow control regulator  150  preferably has an inflated outer diameter of approximately 1.5 cm to 4.0 cm. Preferably, the flow control regulator  150  has an inflated length that is not significantly longer than its inflated diameter, or, more preferably, is shorter than its inflated diameter.  
         [0051]    The aortic catheter  110  may include one or more markers, in the form of radiopaque markers and/or sonoreflective markers, to enhance imaging of the aortic catheter  110  using fluoroscopy or ultrasound, such as transesophageal echography (TEE). In this illustrative embodiment, the aortic catheter  110  includes a distal radiopaque marker  114  positioned within the flow control regulator  150 . The radiopaque marker 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.  
         [0052]    The distal tip  120  is made from any number of known materials such as 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 distal tip may be made from a temperature sensitive material having transition temperatures wherein at 0 degrees Celsius the material is extremely hard, at 25 degrees Celsius the material is of sufficient rigidity to be inserted into a vessel atraumatically and at 35 degrees Celsius the material is very flexible and non-traumatic. A method of achieving the above-described results is to place the temperature sensitive tip in a 4 degree saline solution preoperatively to be inserted at the appropriate time during the surgical procedure. In one illustrative embodiment the tip is made from a temperature sensitive polyurethane such as TECOFLEX or TECOPHILIC. Alternatively, the distal tip may be made of the same material as the catheter shaft  111 , or of a soft material for atraumatic introduction into the aorta. The distal tip  120  may have multiple corporeal flow ports  112  to reduce the “sandblasting” effect when oxygenated blood is infused through the corporeal perfusion lumen  133  or alternatively may have a single opening with a blood diffuser (not shown).  
         [0053]    [0053]FIG. 5 is a schematic diagram showing an aortic catheter  510  according to the present invention deployed within a patient&#39;s aorta. Mounted to the proximal end  530  of the catheter shaft  511  is a manifold  560  with fittings for each of the catheter lumens. The arch perfusion lumen  535  is connected to a ¼ inch barb connector  580  for coupling to a perfusion pump or the like and a luer connector  581 , which may be used for monitoring perfusion pressure, for withdrawing fluid samples or for injecting medications or other fluids. The balloon inflation lumen  540  is connected to a luer connector  548  or other fitting suitable for connection to a syringe or balloon inflation device. The corporeal perfusion lumen  533  is connected to a ⅜ inch to ¼ inch barb reducer  582  for connection to a perfusion pump, and attached to the barb reducer  582  is a luer connector  583 .  
         [0054]    A thorocotomy, such as a median sternotomy, is performed creating direct visualization of the heart and aorta, followed by the placement of a purse string suture and an aortotomy incision inside the purse string on the surface of the ascending aorta. If an optional temperature sensitive tip is used, the catheter  510  may be preoperatively placed in a 4 degree centigrade saline solution to create a more rigid distal tip  120  suitable for insertion through the aortotomy incision. During this procedure or prior thereto, the venous drainage circuit is prepared by cannulating either the vena cava and or the right atrium. Cannulation can be accomplished with either a “two stage” venous cannula, a single stage venous cannula or by separate venous cannulation of the superior and inferior vena cava though the right atrium.  
         [0055]    The aortic catheter  510  is advanced until the flow control regulator  550  is positioned downstream of the left subclavian artery. Evidence of proper position is easily established by pre-positioning the suture ring  517  on the catheter shaft  511  such that, when the suture ring touches the vessel surface proper, position of the flow control regular  550  downstream of the left subclavian has been completed.  
         [0056]    Using a multihead cardiopulmonary bypass pump or the like, oxygenated blood is pumped through the corporeal  535  and arch  533  perfusion lumens and out the corresponding corporeal perfusion ports  512  and the arch perfusion ports  516  to take some of the pumping load off of the heart. The flow control regulator  550  is inflated and an aortic cross clamp  570  is applied, effectively partitioning the aorta. Thereafter, a cardioplegic agent, such cold crystalloid cardioplegia or blood cardioplegia, is infused through a separate cardioplegia needle or catheter placed in the aortic root upstream of the cross clamp  570  to induce cardioplegic arrest. Normothermic perfusion is maintained through the corporeal perfusion ports  512  and hypothermic perfusion is maintained through the arch perfusion ports  516 . Arrest of the heart is maintained by infusing the cardioplegic agent through a cardioplegia needle, an antegrade infusion catheter or by retrograde infusion through a coronary sinus catheter as long as necessary for completion of the surgical procedure.  
         [0057]    Perfusion temperatures, perfusate compositions and flow rates may be optimized to each of the segmented regions of the patient&#39;s circulation for optimal organ preservation while on cardiopulmonary bypass. While the aortic catheter  510  is deployed the rigid yet flexible coil reinforced shaft  11  stabilizes and anchors the flow control regulator  550  preventing upstream or downstream migration of the flow control regulator  550  due to differential pressures within the aorta. The pressure differential on the flow control regulator  550  also helps to place the shaft  511  in tension, further helping to prevent migration of the flow control regulator. At the completion of the surgical procedure, the external cross clamp is removed to allow oxygenated blood to flow into the patient&#39;s coronary arteries, whereupon the heart should resume normal sinus rhythm after the affects of the cardioplegia have sufficiently dissipated. If necessary, cardioversion or defibrillation shocks may be applied to restart the heart. The patient is then weaned off of bypass and the aortic catheter  510  and any other cannulae are withdrawn. inflation of the actuating balloon  1198  will lift the valve leaflets  1151  away from the elongated catheter shaft  1111 . Inflation of the small actuating balloon  1198  in certain embodiments can create the initial expansion of the valve leaflet  1151 , after which positive pressure flow downstream of the cross clamp  1170  further expands the leaflet to at least partially occlude the descending aorta. Alternatively, the small actuating balloon  1198  may be designed to completely actuate the valve leaflet  1151  to the desired diameter based on an increase in inflation volume to correspond to the desired diameter.  
         [0058]    [0058]FIG. 12 depicts the peripheral flow control valve regulator  1050  of FIG. 11 in the undeployed state wherein the valve leaflets  1251  have a low profile around the catheter shaft  1211  creating a smooth outer surface when the small actuating balloon  1298  is uninflated. This low profile is especially beneficial when inserting and removing the catheter from the ascending aorta in order to prevent excessive trauma to the exterior and interior of the vessel wall.  
         [0059]    [0059]FIG. 13 is a schematic diagram showing a sixth embodiment of the aortic catheter  1310 , having a flow control regulator in the form of a selectively deployable central flow control valve regulator  1350  configured for antegrade deployment via an aortotomy incision in the ascending aorta. In this exemplary embodiment, the flow control regulator  1350  would preferably be in the form of a retrograde, central flow valve, as described in commonly owned, U.S. Pat. Nos. 5,827,237, 5,833,671 and commonly owned, copending patent application Ser. No. 08/664,360, which have previously been incorporated by reference. The central flow control valve regulator  1350  is constructed with a selectively expandable skeleton structure  1354  that is mounted on the catheter shaft  1311 . In this exemplary embodiment, the skeleton structure  1354  has an inflatable outer rim  1352  supported on the catheter shaft  1311  by a plurality of inflatable radial spokes  1351 . One or more valve leaflets  1359  (shown in the open position for clarity in FIG. 13) are pivotally attached to the outer rim  1352  or the radial spokes  1351  of the skeleton structure  1354 . The leaflets  1359  of the central flow valve tend to pivot inward closing the valve in response to positive perfusion pressure in the aortic arch downstream of the cross clamp  1370 .  
         [0060]    [0060]FIGS. 14 through 16 illustrate a seventh embodiment of the aortic catheter of the present invention wherein the central flow control valve regulator  1450  is actively deployed by using a second catheter or tube. In addition to being used as a deployment mechanism, the second catheter or tube may have a separate valve regulator or occlusion balloon mounted thereon to eliminate the use of an external aortic cross clamp. The outer rim  1452  is attached to the spokes  1459  and the spokes  1459  are attached to the inner ring  1451  of the skeleton structure  1354 . The valve leaflets  1451  are deflated and folded or collapsed around the catheter shaft  1411 . Deployment, depicted in FIGS. 15 and 16 sequentially, may be performed by pulling back the outer tube  1470 , exposing the skeleton structure, once proper position has been established and deployment is desired. The skeleton structure  1454  is then inflated through the actuation lumen  1440  expanding the outer rim  1452  and spokes  1451  as shown in FIG. 16. When the central flow control regulator  1450  is fully deployed, the outer rim  1452  of the skeleton structure  1454  is actuated outward toward the vessel wall to at least partially occlude the vessel as illustrated in FIG. 13.  
         [0061]    [0061]FIGS. 17 and 18 illustrate an eighth embodiment of the present invention, wherein the central flow control valve regulator  1750  is mechanically deployed by one or more actuation wires  1753  extending through the elongated catheter shaft  1711  and attached to the valve leaflets  1751 . The central flow control valve regulator  1750  has an expanded or deployed state as shown in FIGS. 17 and 18. FIG. 17 illustrates the central flow control valve regulator  1750  in an open position, and FIG. 18 illustrates the deployed central flow control valve  1750  in the closed position. In the closed position, the central flow control valve regulator leaflets  1751  pivot inward in response to positive pressure on the downstream side of the aortic cross clamp.  
         [0062]    Whereas a particular embodiment of the invention has been described above, for purposes of illustration, it will be understood by those skilled in the art that numerous variations of the details may be made without departing from the invention as defined in the appended claims.  
         [0063]    [0063]FIG. 9 illustrates a fourth embodiment of the present invention where the peripheral flow control valve regulator  950  is actively deployed using an inflation lumen  940  extending through the elongated catheter shaft  911  and terminating at an inflation port  999  within the valve leaflets  951 . In this illustrative embodiment, the valve leaflets  951  are formed using heat bonding or adhesives to create triangular shaped leaflets configured in an overall funnel shape, where the valve leaflets  951  are configured to be inflated through a single inflation port  999 . Alternatively, the valve leaflets  951  may be independent of one another and separately inflatable through an inflation port  999 . Where the leaflets  951  are independent and separately inflatable, their inflated shape is triangular in configuration wherein the apex of the triangle is attached to the catheter shaft  911 . Inflation of the valve leaflets  951  tends to pivot the leaflets outward toward the vessel wall. For maximum occluding, all the valve leaflets  951  are inflated creating an overlapping leaflet arrangement resulting in a complete funnel or umbrella configuration. Alternative shapes, such as squares, rectangles trapezoids or circles may be used to form the valve leaflets  951 , since a variety of shapes are capable of creating an overall occluding mechanism. Inflation of the valve leaflets  951  may be accomplished by using a syringe or power injector connected to the inflation lumen  940  to hydraulically inflate the valve leaflets  951  with saline, water, blood, contrast or any combination thereof.  
         [0064]    [0064]FIG. 10 depicts the peripheral flow control valve regulator  1050  of FIG. 9 in the undeployed state wherein the valve leaflets have a low profile and wrap around the catheter shaft  1011  creating a smooth outer surface. This low profile is especially beneficial when inserting and removing the catheter from the ascending aorta in order to prevent excessive trauma to the exterior and interior of the vessel wall.  
         [0065]    [0065]FIG. 11 shows a fifth embodiment of the present invention where the peripheral flow control valve regulator  1150  is actively deployed by a small actuating balloon  1198  which is inflatable through an inflation lumen  1140  extending through the elongated catheter shaft  1111  and terminating at inflation ports  1199 . In alternate embodiments it is possible to have several actuating balloons  1198 , for example, an actuating balloon  1198  to correspond with each individual leaflet  1151  of the peripheral flow control valve regulator. Nevertheless, hydraulic  
         [0066]    [0066]FIG. 6 is a schematic diagram showing a second embodiment of the aortic catheter  610  with a flow control regulator  650  in the form of a peripheral flow control valve regulator  650 . In this exemplary embodiment, the peripheral flow control valve regulator  650  would preferably be in the form of a retrograde, peripheral flow valve, as described in commonly owned, U.S. Pat. Nos. 5,827,237, 5,833,671 and commonly owned, copending application Ser. No. 08/664,360, which have previously been incorporated by reference. The peripheral flow control valve regulator  650  is constructed with one or more valve leaflets  651  pivotally attached to the catheter shaft  611 .  
         [0067]    The peripheral flow control valve regulator  650  may be passively deployed in response to positive perfusion pressure in the aortic arch downstream of the cross clamp  670 . This pressure passively activates the leaflets  651  by pivoting them outward to seal against the wall of the descending aorta. Alternatively, passive deployment may be accomplished by manufacturing the peripheral flow control valve regulator  650  of biocompatible materials having elastic shape memory that urges the valve leaflets  651  to pivot outward toward the vessel wall.  
         [0068]    In place of or in addition to the passive valve deployment, the valve may be actively deployed. FIGS. 7 and 8 illustrate a third embodiment of the present invention where the peripheral flow control valve regulator  850  is actively deployed by one or more actuation wires  853  extending through, on top, inside or in a separate lumen of the elongated catheter shaft  811  and attached to the valve leaflets  851 . FIG. 7 depicts the peripheral flow control valve regulator  750  in the undeployed state wherein the valve leaflets have a low profile and wrap around the catheter shaft  711  creating a smooth outer surface. This low profile is especially beneficial when inserting and removing the catheter from the ascending aorta in order to prevent excessive trauma to the exterior and interior of the vessel wall. FIG. 8 depicts the peripheral flow control valve regulator  850  in the deployed state wherein the valve leaflets  851  are actuated outward from the catheter shaft  811  through the attached actuation wires  853 . The actuation wires  853  may be within the catheter shaft, on the outside of the catheter shaft or have their own separate actuating lumens. In any embodiment, the actuation wires  853  actuate the valve leaflets outward toward the vessel wall.