Reoperation on prosthetic heart valves. An analysis of risk factors in 552 patients.

Five hundred fifty-two patients underwent a total of 617 reoperations for repair or replacement of a prosthetic heart valve. Operative mortality for first reoperation (530 patients) was 5.9% for the aortic position and 19.6% for the mitral position. Overall operative mortality was 14% for second reoperation (69 patients) and 7% for third reoperation (14 patients). In addition to valve position, operative mortality for first reoperation appeared to be related to pre-reoperation functional class and urgency of operation. First reoperation for mitral valve patients in New York Heart Association (NYHA) Class II was 4.2%; for Class III, 9.3%; and for Class IV, 41%. In the aortic position, operative mortality was 2.4% for Class I, 1.6% for Class II, 6.3% for Class III, and 20.8% for Class IV. The mortality for elective mitral valve reoperation was 0%; for urgent operation, 20.3%; and for emergency procedures, 54.5%. Elective aortic valve reoperation carried a 1.4% mortality; urgent procedures, 8%; and emergency procedures, 37.5%. No significant differences in bleeding complications were noted between reoperations and initial valve replacement. The data appear to suggest that when significant valve dysfunction is first noted, reoperation should be undertaken to minimize operative risk.