Results of aortic valve replacement with and without coronary artery perfusion

Aortic valve replacement: a 9-year experience

Experience with aortic valve replacement over a 9-year period is reviewed. Hospital mortality was 5.0%, with an additional late mortality of 15.0% during a mean follow-up period of 4.3 years. There was a 7.5% mortality among the 93 patients who were operated on using direct coronary perfusion. There were no early deaths among the 48 patients operated on using cold cardioplegic arrest. Paravalvular leaks developed in 20 patients, and 9 had reoperation. There were no early deaths following elective reoperations for prosthetic valve dysfunction, but urgent reoperation was associated with a 40% mortality. Eighty percent of all patients are still alive at a maximum follow-up of 9 years. Eighty-six percent of the survivors who were in New York Heart Association Functional Class III or IV before operation are now in Class I or II. Hypothermic cardioplegic arrest was found to be preferable to coronary perfusion as a method of myocardial protection during aortic valve replacement. Patients with paravalvular leaks who have a history of left ventricular failure prior to aortic valve replacement should be considered candidates for early elective reoperation, owing to the significantly greater mortality associated with urgent reoperation.

Multiple valve replacement: changing status

Review of our experience with multiple valve replacement over a 6-year-period revealed a recent marked reduction in operative risk. Operative mortality for 62 patients operated on before 1974 was 34%; for 44 patients operated on since 1974, mortality was only 11%. In both groups, mortality was clearly related to the preoperative cardiac functional status. Several recent technical advances including myocardial protection by topical hypothermia, shortened perfusion time, and the intraaortic balloon pump may all have contributed to the reduced operative risk.

Myocardial protection during aortic valve replacement

The results following aortic valve replacement (AVR) were compared in 40 patients in whom the myocardium was protected by topical hypothermic arrest or continuous coronary perfusion with sustained electrical fibrillation (Group A) and 40 similar patients in whom the hearts were also continuously perfused but were kept in the beating state (Group B). The operative mortality was not greatly different between the two groups, being 10 and 5%, respectively. The postperfusion cardiac performance was strikingly different, however. Seventeen patients (43%) in Group A required inotropic support, while this was necessary in only 1 patient (3%) in Group B. In this instance, recurrent ventricular fibrillation persisted despite attempts at reversion. These data show that the myocardium is preserved best during AVR when continuous coronary perfusion is used and the heart is maintained in the beating state.

Long-term survival after aortic valve replacement using Smeloff-Cutter prosthesis

The long-term prognosis of 187 consecutive patients who received single aortic valve replacement using Smeloff-Cutter prosthesis was studied. Of the 163 patients who survived the operation, a long-term follow-up (up to eight years) was obtained in 153 patients (95%). A total of 34 patients (22%) died during the follow-up period. Including the hospital mortality, the actuarial survival rate of our patients with Smeloff-Cutter prosthesis was 0.69 after the fifth year and 0.611 after the eighth year of follow-up. This is similar to the actuarial survival rate of patients with Starr-Edwards prosthesis but it appears significantly better than the expected survival rate of symptomatic patients with aortic stenosis treated without surgery. Thus, this result supports the contention that aortic valve surgery in properly selected patients can prolong life expectancy in addition to relieving symptoms in patients with aortic valve disease. The majority of surviving patients reported to have improved (88%) since the operation and to be symptom free (82%).

Coronary artery perfusion

Perfusion of the coronary arteries with oxygenated blood during cardiopulmonary bypass should in theory offer perfect myocardial protection, but the difficulties sometimes encountered with direct cannulation and the hazards of prolonged fibrillation in spite of perfusion raise questions regarding its universal efficacy. Arguments for and against coronary artery perfusion are presented and the hazards of partial perfusion are stressed.

Resection of the ascending aorta using profound local hypothermia for myocardial protection

Resection of the ascending aorta with or without aortic valve replacement requires prolonged interruption of myocardial blood flow. Profound local cardiac hypothermia was used in 8 patients, 5 of whom had simultaneous aortic valve replacement. Three patients with acute dissections were encountered, one with cardiac tamponade secondary to intrapericardial rupture. The duration of aortic cross-clamp time varied from 43 to 122 minutes. There were no complications related to the cooling technique. There were no operative or hospital deaths. One patient died of myocardial infarction at 6 weeks. These results coupled with the experience of others suggest that coronary perfusion during periods of obligatory anoxia in unnecessary. Local cardiac hypothermia offers a satisfactory alternative for myocardial protection during prolonged aortic crossclamping.