Cardiac valvular surgery in dialysis patients: comparison of surgical outcome for mechanical versus bioprosthetic valves

Abstract

There has been a changing preference for bioprosthetic valves over mechanical valves in dialysis patients, but there is still much controversy. We reviewed our 17-year experience and assessed the influence of prosthesis choice. From 1990 to 2007, a total of 63 consecutive dialysis patients who underwent valvular surgery (64 operations including one reoperation) at our hospital were retrospectively reviewed. The mean age of the patients was 58.3 +/- 9.0 years. The reasons for dialysis were glomerulonephritis (n = 32) and diabetes (n = 10). The major preoperative diagnosis was aortic stenosis (n = 44). The surgical procedures included aortic valve replacement (n = 44), mitral valve replacement (n = 7), double valvular replacement (n = 7), and mitral valve repair (n = 5). Prostheses for valve replacement were mechanical valves (n = 37) or bioprosthetic valves (n = 22). Follow-up was accomplished in 95.2%, and the mean follow-up period was 49 months. Actuarial survivals at 1, 5, and 10 years were 85%, 64%, and 45% respectively. Freedom from cardiovascular events at 1 and 5 years was 61% and 41%, respectively. Mechanical valve patients had significantly higher early mortality than bioprosthetic valve patients (P = 0.03). However, both mechanical and bioprosthetic valve patients had similar survival and event-free rates (P = 0.87 and P = 0.27, respectively) in the midterm results. The mechanical group had a higher rate of bleeding events. There was no structural valve deterioration up to the 5-year follow-up. The choice of prosthesis did not influence the surgical outcome except for early mortality. Careful consideration of preventive measures against bleeding is important, and prosthesis selection should be based on the patient's profile as well as the criteria for nondialysis patients.