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Aortic Valve Surgery Using the Magovern Prosthesis
Aortic Valve Surgery Using the Magovern Prosthesis Stewart M. Scott, M.D., Robert G. Fish, M.D., Timothy Takaro, M.D., and William H. Sewell, M.D.
T
he Magovern sutureless aortic valve prosthesis* [l] was devised in an attempt to simplify the technique of insertion and to shorten the perfusion time required for successful aortic valve replacement. Whether or not it is worthwhile will depend on observations regarding mortality, morbidity, and long-term results in a significant number of cases. This report concerns our experience with 24 patients in whom Magovern prostheses were employed. All patients were evaluated preoperatively with left heart pressures and cineangiocardiography. Twelve patients had mixed aortic valve lesions. Stenosis was predominant in 15. Calcification was severe in 14. Nine patients had pure aortic insufficiency. T w o patients were found to have luetic aortitis, and another had cystic medial necrosis with aneurysmal aortic dilatation. All patients had severe impairment of cardiac function. Four patients had undergone previous aortic valve surgery. One had had a transventricular dilatation of the aortic valve six years earlier. Sculpturing procedures had been performed in two patients, and a fourth patient had a Bahnson leaflet replacement for a destroyed aortic valve leaflet. One patient also had a simultaneous StarrEdwards mitral valve replacement. RESULTS
There were two deaths during surgery. I n the first instance operation was performed as an emergency procedure in what otherwise appeared to be a hopeless situation. A second patient died on the table in severe metabolic acidosis. Two early postoperative deaths occurred. One patient died of renal shutdown on the tenth postoperative day. Another patient died sudFrom the Veterans Administration Hospital, Oteen, N.C. The cooperation of Dr. George Magovern and Mr. Harry Cromic in this study is gratefully acknowledged. Presented at the Eleventh Annual Meeting of the Southern Thoracic Surgical Association, Atlanta, Ga., Nov. 12-14, 1964. 'Surgitool Incorporated, Pittsburgh, Pa.
VOL. 1 , NO.
4,
JULY,
196;
463
SCOTT, FISH, TAKARO, AND SEWELL
denly on the seventh postoperative day with an embolus in the left coronary artery. There were two later deaths. T h e first occurred in a patient with luetic aortic insufficiency who had done well immediately postoperatively. Shortly after discharge from the hospital this patient developed recurrent intractable congestive failure and a change of blood pre,qsure from 110/70 to 150/40. H e died three months postoperatively after refusing reoperation. Postmortem examination revealed separation of the prosthesis along 25% of the aortic wall. Another death occurred suddenly at six weeks in a patient who was doing quite well. Autopsy failed to disclose the cause of death; the valve was in good position and firmly attached. Although the 18 surviving patients showed marked clinical improvement, two patients have been partially incapacitated from the effects of cerebral emboli. I n addition to the usual aortic systolic murmur, 8 patients manifested a classic aortic insufficiency murmur of grade 1 to 2 intensity after surgery. I n one patient with a wide pulse pressure (140/40), regurgitant flow about the periphery of the prosthesis was demonstrated by cineangiocardiography. Infection or postcardiotomy syndrome was not encountered. One patient developed a temporary complete heart block which converted to normal conduction while the patient was still in the operating room. Six patients experienced embolic episodes, four involving the cerebral circulation. T w o of these patients have moderately disabling left hemiparesis but are ambulatory. T h e others have no residual. Anterior tibia1 artery occlusion occurred in one patient, and a sixth patient died as a result of an embolus in the coronary artery. Although anticoagulant therapy was not initially employed, all patients are now routinely anticoagulated on the sixth or seventh postoperative day. DISCUSSION
T h e complications encountered in this series are not peculiar to the Magovern prosthesis. Dehiscence and embolic complications have been reported with other prosthetic valves. This series is not sufficiently large to draw statistically significant conclusions regarding operative mortality. Interestingly there were no surgical deaths in the first 14 patients. Long-term results in the surviving patients have been impressive. T h e presence of an aortic insufficiency murmur in 8 of the surviving patients has been a matter of continuing concern. Follow-up at this time, however, suggests that the degree of regurgitation present is of little dynamic significance in 6, since all have shown impressive objec-
464
THE ANNALS OF THOKACIC SURGERY
NOTE:
Magovern Aortic Valve
tive and subjective clinical improvement. Four have maintained normal pulse and diastolic pressures; 2 are borderline. T h e remaining 2 cases with low diastolic and wide pulse pressures have also shown significant improvement, presumably related to the correction of severe stenotic lesions. These patients have been closely followed for 20 and 17 months, respectively, to determine the need for reoperation. This murmur is due to leakage about the periphery of the valve and is more likely to occur in the presence of heavy calcification or in the presence of a very widely dilated aortic ring. O n occasion either of these can preclude the use of the Magovern prosthesis. However, it should be noted that all the aortic insufficiency murmurs occurred in the first 11 patients. It may be that experience and improved technique have avoided this problem in the last 10 patients. In the absence of routine postoperative anticoagulant therapy, we encountered embolic phenomena in 4 patients. Even with routine anticoagulation beginning on the seventh postoperative day, 2 additional patients had embolic episodes. Presently we are continuing to anticoagulate all patients for an indefinite period. T h e advantage of a technique that permits prosthetic aortic valve replacement without coronary perfusion under normothermic conditions is obvious. W e believe the results obtained in this group of patients warrant continued trial of this prosthesis. REFERENCE
1. Magovern, G. J., Kent, E. M., and Cromie, H. W. Sutureless artificial heart valves. Circzilation 27:784, 1963.
VOL.
I , NO.
4,
JULY,
1965
465
T
he Magovern sutureless aortic valve prosthesis* [l] was devised in an attempt to simplify the technique of insertion and to shorten the perfusion time required for successful aortic valve replacement. Whether or not it is worthwhile will depend on observations regarding mortality, morbidity, and long-term results in a significant number of cases. This report concerns our experience with 24 patients in whom Magovern prostheses were employed. All patients were evaluated preoperatively with left heart pressures and cineangiocardiography. Twelve patients had mixed aortic valve lesions. Stenosis was predominant in 15. Calcification was severe in 14. Nine patients had pure aortic insufficiency. T w o patients were found to have luetic aortitis, and another had cystic medial necrosis with aneurysmal aortic dilatation. All patients had severe impairment of cardiac function. Four patients had undergone previous aortic valve surgery. One had had a transventricular dilatation of the aortic valve six years earlier. Sculpturing procedures had been performed in two patients, and a fourth patient had a Bahnson leaflet replacement for a destroyed aortic valve leaflet. One patient also had a simultaneous StarrEdwards mitral valve replacement. RESULTS
There were two deaths during surgery. I n the first instance operation was performed as an emergency procedure in what otherwise appeared to be a hopeless situation. A second patient died on the table in severe metabolic acidosis. Two early postoperative deaths occurred. One patient died of renal shutdown on the tenth postoperative day. Another patient died sudFrom the Veterans Administration Hospital, Oteen, N.C. The cooperation of Dr. George Magovern and Mr. Harry Cromic in this study is gratefully acknowledged. Presented at the Eleventh Annual Meeting of the Southern Thoracic Surgical Association, Atlanta, Ga., Nov. 12-14, 1964. 'Surgitool Incorporated, Pittsburgh, Pa.
VOL. 1 , NO.
4,
JULY,
196;
463
SCOTT, FISH, TAKARO, AND SEWELL
denly on the seventh postoperative day with an embolus in the left coronary artery. There were two later deaths. T h e first occurred in a patient with luetic aortic insufficiency who had done well immediately postoperatively. Shortly after discharge from the hospital this patient developed recurrent intractable congestive failure and a change of blood pre,qsure from 110/70 to 150/40. H e died three months postoperatively after refusing reoperation. Postmortem examination revealed separation of the prosthesis along 25% of the aortic wall. Another death occurred suddenly at six weeks in a patient who was doing quite well. Autopsy failed to disclose the cause of death; the valve was in good position and firmly attached. Although the 18 surviving patients showed marked clinical improvement, two patients have been partially incapacitated from the effects of cerebral emboli. I n addition to the usual aortic systolic murmur, 8 patients manifested a classic aortic insufficiency murmur of grade 1 to 2 intensity after surgery. I n one patient with a wide pulse pressure (140/40), regurgitant flow about the periphery of the prosthesis was demonstrated by cineangiocardiography. Infection or postcardiotomy syndrome was not encountered. One patient developed a temporary complete heart block which converted to normal conduction while the patient was still in the operating room. Six patients experienced embolic episodes, four involving the cerebral circulation. T w o of these patients have moderately disabling left hemiparesis but are ambulatory. T h e others have no residual. Anterior tibia1 artery occlusion occurred in one patient, and a sixth patient died as a result of an embolus in the coronary artery. Although anticoagulant therapy was not initially employed, all patients are now routinely anticoagulated on the sixth or seventh postoperative day. DISCUSSION
T h e complications encountered in this series are not peculiar to the Magovern prosthesis. Dehiscence and embolic complications have been reported with other prosthetic valves. This series is not sufficiently large to draw statistically significant conclusions regarding operative mortality. Interestingly there were no surgical deaths in the first 14 patients. Long-term results in the surviving patients have been impressive. T h e presence of an aortic insufficiency murmur in 8 of the surviving patients has been a matter of continuing concern. Follow-up at this time, however, suggests that the degree of regurgitation present is of little dynamic significance in 6, since all have shown impressive objec-
464
THE ANNALS OF THOKACIC SURGERY
NOTE:
Magovern Aortic Valve
tive and subjective clinical improvement. Four have maintained normal pulse and diastolic pressures; 2 are borderline. T h e remaining 2 cases with low diastolic and wide pulse pressures have also shown significant improvement, presumably related to the correction of severe stenotic lesions. These patients have been closely followed for 20 and 17 months, respectively, to determine the need for reoperation. This murmur is due to leakage about the periphery of the valve and is more likely to occur in the presence of heavy calcification or in the presence of a very widely dilated aortic ring. O n occasion either of these can preclude the use of the Magovern prosthesis. However, it should be noted that all the aortic insufficiency murmurs occurred in the first 11 patients. It may be that experience and improved technique have avoided this problem in the last 10 patients. In the absence of routine postoperative anticoagulant therapy, we encountered embolic phenomena in 4 patients. Even with routine anticoagulation beginning on the seventh postoperative day, 2 additional patients had embolic episodes. Presently we are continuing to anticoagulate all patients for an indefinite period. T h e advantage of a technique that permits prosthetic aortic valve replacement without coronary perfusion under normothermic conditions is obvious. W e believe the results obtained in this group of patients warrant continued trial of this prosthesis. REFERENCE
1. Magovern, G. J., Kent, E. M., and Cromie, H. W. Sutureless artificial heart valves. Circzilation 27:784, 1963.
VOL.
I , NO.
4,
JULY,
1965
465