Retrograde venous cardioplegia catheters and methods of use and manufacture

Claim 2

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture, the aggregate of said balloon apertures having a total cross-sectional area which is greater than the cross-sectional area of the infusion lumen; at least one infusion lumen outlet in the infusion lumen positioned between the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, a portion of the cardioplegic solution enters the chamber through the at least one balloon aperture and a portion of the cardioplegic solution exits the infusion lumen and the cannula through the at least one infusion lumen outlet, the aggregate of said infusion lumen outlets having a total cross-sectional area which is in the range of from about twenty-five percent to about seventy-five percent of the cross-sectional area of the infusion lumen, thereby creating a pressure within the infusion lumen which causes the cardioplegic solution to enter the chamber through the at least one balloon aperture in order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; and at least one sensing lumen orifice in the sensing lumen located at a point between the balloon and the distal end of the cannula which is remote from the at least one infusion lumen outlet, said sensing lumen orifice having a cross-sectional area greater than the cross-sectional area of the sensing lumen.

Claim 3

A catheter as defined in claim 1, further comprising a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 4

A catheter as defined in claim 2, wherein the tip located at the distal end of the cannula is constructed of a material having a softness in the range of about 55 to about 60 durometer, Shore-A.

Claim 5

A catheter as defined in claim 3, wherein the tip located at the distal end of the cannula is constructed of medical grade polyvinyl chloride.

Claim 6

A catheter as defined in claim 2, wherein the distal end of the balloon is located back from the tip a distance in the range from about 2 centimeters to about 6 centimeters.

Claim 7

A catheter as defined in claim 1, further comprising means attached to the proximal end of the infusion lumen for introducing the cardioplegic solution into and through the infusion lumen.

Claim 8

A catheter as defined in claim 6, further comprising means attached to the proximal end of the sensing lumen for sensing the pressure of the cardioplegic solution at the at least one sensing lumen orifice.

Claim 9

A catheter as defined in claim 6, further comprising means for stopping the introduction of the cardioplegic solution into the infusion lumen when the pressure of the cardioplegic solution exiting the at least one infusion lumen outlet exceeds a predetermined maximum pressure.

Claim 10

A catheter as defined in claim 1, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during the insertion of the cannula into the coronary sinus and thereby encouraging the dealing engagement of the balloon with the walls of the coronary sinus.

Claim 11

A catheter as defined in claim 9, wherein the balloon taper is in the range from about 25° to about 35° measured from the longitudinal axis of the cannula.

Claim 12

A catheter as defined in claim 1, wherein the aggregate of said balloon apertures has a total cross-sectional area in the range of from about 1.5 to about 5 times the cross-sectional area of the infusion lumen.

Claim 13

A catheter as defined in claim 1, wherein the aggregate of said balloon apertures has a total cross-sectional area in the range from about 2 to about 3 times the cross-sectional area of the infusion lumen.

Claim 14

A catheter as defined in claim 1, wherein the balloon, when filled with cardioplegic solution, has a cross-sectional diameter in the range of from about 1.6 to about 2.0 centimeters.

Claim 15

A catheter as defined in claim 1, wherein the balloon when filled with cardioplegic solution, has a cross-sectional diameter in the range of from about 1.7 to about 1.8 centimeters.

Claim 16

A catheter as defined in claim 1, wherein the dual lumen cannula is constructed of a material having a softness in the range from about 75 to about 85 durometer, Shore-A.

Claim 17

A catheter as defined in claim 15, wherein the dual lumen cannula is constructed of medical grade polyvinyl chloride.

Claim 18

A catheter as defined in claim 1, wherein the balloon is constructed of a material having a percent elongation greater than about 600%.

Claim 19

A catheter as defined in claim 17, wherein the balloon is constructed of polyurethane.

Claim 20

A catheter as defined in claim 1, further comprising a plurality of balloon apertures in the infusion lumen.

Claim 21

A catheter as defined in claim 19, further comprising a plurality of infusion lumen outlets in the infusion lumen.

Claim 22

A catheter as defined in claim 20, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 23

A catheter as defined in claim 19, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 24

A catheter as defined in claim 1, further comprising a plurality of infusion lumen outlets in the infusion lumen.

Claim 25

A catheter as defined in claim 23, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 26

A catheter as defined in claim 1, wherein the cross-sectional area of sensing lumen orifice is in the range from about 2 to about 3 times the cross-sectional area of the sensing lumen.

Claim 27

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture; at least one infusion lumen outlet in the infusion lumen positioned between the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, a portion of the cardioplegic solution enters the chamber through the at least one balloon aperture and a portion of the cardioplegic solution exits the infusion lumen outlet, the aggregate of said infusion lumen outlets having a total cross-sectional area which is less than the total cross-section areas of the aggregate of said balloon apertures in the infusion lumen, thereby creating a pressure within the infusion lumen which causes the cardioplegic solution to enter the chamber through the at least one balloon aperture in order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point between the balloon and the distal end of the cannula which is remote from the at least one infusion lumen outlet, said sensing lumen orifice having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof and a predetermined curve at the distal end thereof, said stylet being constructed of a rigid material such that the stylet can be used to position the flexible cannula in the coronary sinus with minimal trauma to the heart tissues.

Claim 28

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture; at least one infusion lumen outlet in the infusion lumen positioned between the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, a portion of the cardioplegic solution enters the chamber through the at least one balloon aperture and a portion of the cardioplegic solution exits the infusion lumen outlet, the aggregate of said infusion lumen outlets having a total cross-sectional area which is less than the total cross-section areas of the aggregate of said balloon apertures in the infusion lumen, thereby creating a pressure within the infusion lumen which causes the cardioplegic solution to enter the chamber through the at least one balloon aperture in order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point between the balloon and the distal end of the cannula which is remote from the at least one infusion lumen outlet, said sensing lumen orifice having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof and a predetermined curve at the distal end thereof, said stylet being constructed of a rigid material such that the stylet can be used to position the flexible cannula in the coronary sinus with minimal trauma to the heart tissues.

Claim 29

A catheter defined in claim 26, further comprising a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 30

A catheter as defined in claim 27, wherein the tip located at the distal end of the cannula is constructed of a material having a softness in the range of from about 55 to about 60 durometer, Shore-A.

Claim 31

A catheter as defined in claim 28, wherein the tip located at the distal end of the cannula is constructed of medical grade polyvinyl chloride.

Claim 32

A catheter as defined in claim 27, wherein the distal end of the balloon is located back from the tip a distance in the range from about 2 centimeters to about 6 centimeters.

Claim 33

A catheter as defined in claim 26, further comprising means attached to the proximal end of the infusion lumen for introducing the cardioplegic solution into and through the infusion lumen.

Claim 34

A catheter as defined in claim 31, further comprising means attached to the proximal end of the sensing lumen for sensing the pressure of the cardioplegic solution at the at least one sensing lumen orifice.

Claim 35

A catheter as defined in claim 31, further comprising means for stopping the introduction of the cardioplegic solution into the infusion lumen when the pressure of the cardioplegic solution exiting the at least one infusion lumen outlet exceeds a predetermined maximum pressure.

Claim 36

A catheter as defined in claim 26, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during the insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus.

Claim 37

A catheter as defined in claim 34, wherein the balloon taper is in the range from about 25° to about 35° measured from the longitudinal axis of the cannula.

Claim 38

A catheter as defined in claim 26, wherein the aggregate of said balloon apertures has a total cross-sectional area in the range of from about 1.5 to about 5 times the cross-sectional area of the infusion lumen.

Claim 39

A catheter as defined in claim 26, wherein the aggregate of said balloon apertures has a total cross-sectional area in the range from about 2 to about 3 times the cross-sectional area of the infusion lumen.

Claim 40

A catheter as defined in claim 26, wherein the balloon, when filled with cardioplegic solution, has a cross sectional diameter in the range of from about 1.6 to about 2.0 centimeters.

Claim 41

A catheter as defined in claim 26, wherein the balloon when filled with cardioplegic solution, has a cross-sectional diameter in the range of from about 1.7 to about 1.8 centimeters.

Claim 42

A catheter as defined in claim 26, wherein the dual lumen cannula is constructed of a material having a softness in the range from about 75 to about 85 durometer, Shore-A.

Claim 43

A catheter as defined in claim 40, wherein the dual lumen cannula is constructed of medical grade polyvinyl chloride.

Claim 44

A catheter as defined in claim 26, wherein the balloon is constructed of a material having a percent elongation greater than about 600%.

Claim 45

A catheter as defined in claim 42, wherein the balloon is constructed of polyurethane.

Claim 46

A catheter as defined in claim 26, further comprising a plurality of balloon apertures in the infusion lumen.

Claim 47

A catheter as defined in claim 44, wherein the distal end of the balloon is located back from the tip a distance in the range from about 2 centimeters to about 6 centimeters.

Claim 48

A catheter as defined in claim 45, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 49

A catheter as defined in claim 44, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 50

A catheter as defined in claim 26, further comprising a plurality of infusion lumen outlets in the infusion lumen.

Claim 51

A catheter as defined in claim 48, wherein the balloon is tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during insertion of the cannula into the coronary sinus and thereby encouraging the sealing engagement of the balloon with the walls of the coronary sinus, said catheter further comprising: a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula.

Claim 52

A catheter as defined in claim 26, wherein the cross-sectional area of sensing lumen orifice is in the range from about 2 to about 3 times the cross-sectional area of the sensing lumen.

Claim 53

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula; a balloon attached about and to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula, said balloon being tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during the insertion of the cannula into the coronary sinus and thereby encouraging sealing engagement of the balloon with the walls of the coronary sinus; a plurality of balloon apertures in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the balloon apertures, the aggregate of said balloon apertures having a total cross-sectional area in the range from about 1.5 to about 5 times the cross-sectional area of the infusion lumen; a plurality of infusion lumen outlets in the infusion lumen positioned between the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, a portion of the cardioplegic solution enters the chamber through the balloon apertures and a portion of the cardioplegic solution exits the infusion lumen and the cannula through the infusion lumen outlets, the aggregate of said infusion lumen outlets having a total cross-sectional area which is in the range from about twenty-five to about seventy-five percent cross-section area of the infusion lumen, thereby creating a pressure within the infusion lumen which causes the cardioplegic solution to enter the inner chamber through the balloon apertures in order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point between the balloon and the distal end of the cannula which is remote from the at least one infusion lumen outlet, said sensing lumen orifice having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof, and a predetermined curve at the distal end thereof, said stylet being constructed of a rigid material such that the stylet can be used to position the flexible cannula in the coronary sinus with minimal trauma to the heart tissue.

Claim 54

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a tip located at the distal end of the cannula such that the distal ends of the infusion lumen and the sensing lumen are occluded at the tip, the tip being configured and made of a material such that trauma to the coronary sinus is minimized during insertion of the cannula; a balloon attached about and to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula, said balloon being tapered from the distal end to the proximal end of the balloon, thereby minimizing trauma during the insertion of the cannula into the coronary sinus and thereby encouraging sealing engagement of the balloon with the walls of the coronary sinus; a plurality of balloon apertures in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the balloon apertures, the aggregate of said balloon apertures having a total cross-sectional area in the range from about 1.5 to about 5 times the cross-sectional area of the infusion lumen; a plurality of infusion lumen outlets in the infusion lumen positioned between the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, a portion of the cardioplegic solution enters the chamber through the balloon apertures and a portion of the cardioplegic solution exits the infusion lumen and the cannula through the infusion lumen outlets, the aggregate of said infusion lumen outlets having a total cross-sectional area which is in the range from about twenty-five to about seventy-five percent cross-section area of the infusion lumen, thereby creating a pressure within the infusion lumen which causes the cardioplegic solution to enter the inner chamber through the balloon apertures in order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point between the balloon and the distal end of the cannula which is remote from the at least one infusion lumen outlet, said sensing lumen orifice having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof, and a predetermined curve at the distal end thereof, said stylet being constructed of a rigid material such that the stylet can be used to position the flexible cannula in the coronary sinus with minimal trauma to the heart tissue.

Claim 55

A catheter as defined in claim 51, wherein the aggregate of said balloon apertures has a total cross-sectional area in the range from about 2 to about 3 times the cross-sectional area of the infusion lumen.

Claim 56

A catheter as defined in claim 51, wherein the balloon, when filled with cardioplegic solution, has a cross-sectional diameter in the range of from about 1.6 to about 2.0 centimeters.

Claim 57

A catheter as defined in claim 53, wherein the distal end of the balloon is located back from the tip a distance in the range from about 2 centimeters to about 6 centimeters.

Claim 58

A catheter as defined in claim 54, wherein the balloon is constructed of a material having a percent elongation greater than about 600%.

Claim 59

A catheter as defined in claim 55, wherein the balloon is constructed of polyurethane.

Claim 60

A catheter as defined in claim 54, wherein the balloon taper is in the range from about 25° to about 35° measured from: the longitudinal axis of the cannula.

Claim 61

A catheter as defined in claim 54, further comprising means attached to the proximal end of the infusion lumen for introducing the cardioplegic solution into and through the infusion lumen.

Claim 62

A catheter as defined in claim 58, further comprising means attached to the proximal end of the sensing lumen for sensing the pressure of the cardioplegic solution at the sensing lumen orifice.

Claim 63

A catheter as defined in claim 59, further comprising means for stopping the introduction of the cardioplegic solution into the infusion lumen when the pressure of the cardioplegic solution exiting the sensing lumen orifice exceeds a predetermined maximum pressure.

Claim 64

A catheter as defined in claim 54, wherein the tip located at the distal end of the cannula is constructed of a material having a softness in the range from about 55 to about 60 durometer, Shore-A.

Claim 65

A catheter as defined in claim 61, wherein the tip located at the distal end of the cannula is constructed of medical grade polyvinyl chloride.

Claim 66

A catheter as defined in claim 61, wherein the dual lumen cannula is constructed of a material having a softness in the range from about 75 to about 85 durometer, Shore-A.

Claim 67

A catheter as defined in claim 63, wherein the dual lumen cannula is constructed of medical grade polyvinyl chloride.

Claim 68

A catheter as defined in claim 51, wherein the balloon when filled with cardioplegic solution, has a cross-sectional diameter in the range of from about 1.7 to about 1.8 centimeters.

Claim 69

A catheter as defined in claim 51, wherein the cross-sectional area of sensing lumen orifice is in the range from about 2 to about 3 times the cross-sectional area of the sensing lumen.

Claim 72

A method for the retrograde administration of cardioplegic solution as defined in claim 67, further comprising the step of monitoring the pressure of the cardioplegic solution within the coronary sinus in order to minimize damage to the coronary sinus by excessive pressures and flow rates of the cardioplegic solution.

Claim 73

A method for the retrograde administration of a cardioplegic solution as defined in claim 68, further comprising the step of terminating the injection of the cardioplegic solution through the cannula if the fluid pressure within the coronary sinus exceeds a predetermined maximum pressure.

Claim 74

A method for the retrograde administration of cardioplegic solution as defined in claim 67, further comprising terminating the injection of the cardioplegic solution through the catheter such that the self-filling balloon empties to permit normal venous fluid flow into the right atrium.

Claim 75

A method for the retrograde administration of a cardioplegic solution as defined in claim 70, further comprising the step of periodically injecting cardioplegic solution through the cannula and terminating the injection of the cardioplegic solution.

Claim 76

A method for the retrograde administration of a cardioplegic solution as defined in claim 70, wherein after terminating the injection of the cardioplegic solution, antegrade cardioplegia is initiated for a period of time.

Claim 77

A method for the retrograde administration of a cardioplegic solution as defined in claim 67, further comprising the step of maintaining the fluid pressure within the coronary sinus below about 50 mmHg.

Claim 78

A method for the retrograde administration of a cardioplegic solution as defined in claim 67, wherein the cardioplegic solution is injected through the cannula at a flow rate in the range from about 200 ml/min to about 300 ml/min.

Claim 79

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture, the aggregate of said balloon apertures having a total cross-sectional area which is greater than the cross-sectional area of the infusion lumen; at least one infusion lumen outlet in the infusion lumen positioned between the proximal end of the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, the size and configuration of the at least one infusion outlets creates a pressure within the infusion lumen which cause the cardioplegic solution enters the chamber through the at least one balloon aperture in a order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; and at least one sensing lumen orifice in the sensing lumen located at a point proximal of the distal end of the cannula which is remote from the at least one infusion lumen outlet, the aggregate of said sensing lumen orifices having a cross-sectional area greater than the cross-sectional area of the sensing lumen.

Claim 80

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, dual lumen cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture, the aggregate of said balloon apertures having a total cross-sectional area which is greater than the cross-sectional area of the infusion lumen; at least one infusion lumen outlet in the infusion lumen positioned between the proximal end of the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, the size and configuration of the at least one infusion outlets creates a pressure within the infusion lumen which cause the cardioplegic solution enters the chamber through the at least one balloon aperture in a order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; and at least one sensing lumen orifice in the sensing lumen located at a point proximal of the distal end of the cannula which is remote from the at least one infusion lumen outlet, the aggregate of said sensing lumen orifices having a cross-sectional area greater than the cross-sectional area of the sensing lumen.

Claim 83

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture; at least one infusion lumen outlet in the infusion lumen positioned between the proximal end of the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, the size and configuration of the at least one infusion outlets creates a pressure within the infusion lumen which causes the cardioplegic solution enters the chamber through the at least one balloon aperture in a order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point proximal of the distal end of the distal end of the cannula which is remote from the at least one infusion lumen outlet, the aggregate of said sensing lumen orifices having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof and a predetermined curve at the distal end thereof, said stylet handle having a finger loop extending from the distal end of the stylet handle and a thumb rest located at the proximal end of the stylet handle.

Claim 84

A catheter for performing retrograde venous cardioplegia by delivering a cardioplegic solution into the coronary sinus of the heart, the catheter comprising: a flexible, cannula of a size capable of insertion into the coronary sinus of the heart, said cannula having an infusion lumen and a sensing lumen; a balloon attached to the cannula periphery near the distal end of the cannula, thereby forming a chamber between the balloon and the cannula; at least one balloon aperture in the infusion lumen positioned such that the infusion lumen is in communication with the chamber formed by the balloon and the cannula through the at least one balloon aperture; at least one infusion lumen outlet in the infusion lumen positioned between the proximal end of the balloon and the distal end of the cannula such that, when cardioplegic solution passes through the infusion lumen, the size and configuration of the at least one infusion outlets creates a pressure within the infusion lumen which causes the cardioplegic solution enters the chamber through the at least one balloon aperture in a order to fill the balloon until it is turgid and in sealing engagement with the walls of the coronary sinus; at least one sensing lumen orifice in the sensing lumen located at a point proximal of the distal end of the distal end of the cannula which is remote from the at least one infusion lumen outlet, the aggregate of said sensing lumen orifices having a cross-sectional area greater than the cross-sectional area of the sensing lumen; and a stylet removably positioned within the flexible cannula, said stylet having a handle at the proximal end thereof and a predetermined curve at the distal end thereof, said stylet handle having a finger loop extending from the distal end of the stylet handle and a thumb rest located at the proximal end of the stylet handle.

Claim 85

A catheter for performing retrograde venous cardioplegia as defined in claim 77, wherein the stylet handle is configured such that placement of a surgeon's index finger against the finger loop, the ring finger against the stylet handle, and the thumb against the thumb rest enables the catheter to be quickly inserted with the coronary sinus with a slight twist of the surgeon's wrist.

Claim 86

A catheter for performing retrograde venous cardioplegia as defined in claim 77, wherein the stylet handle is configured such that placement of a surgeon's index finger against the finger loop, the ring finger against the stylet handle, and the thumb against the thumb rest enables the catheter to be quickly inserted with the coronary sinus with a slight twist of the surgeon's wrist.