Reoperative surgery for degenerated aortic bioprostheses:: predictors for emergency surgery and reoperative mortality

Objective: The long-term outcome of patients with aortic bioprosthetic valves could be improved by decreasing the reoperative mortality rate. Methods: Predictors of emergency reoperation and reoperative mortality were identified retrospectively in 172 patients who had the first bioprosthetic aortic valve replacement between 1975 and 1988 (mean age 46 +/- 13 years) and were subjected to replacement of the degenerated bioprostheses between 1978 and 1997 (mean age 56 +/- 14 years). Emergency reoperation had to be performed in 31 patients (18%). Results: The operative mortality was 5.2% (9/172), 22.6% for emergency (odds ratio 11.17; 95%-confidence limit 4.33-28.85) and 1.4% for elective replacement of the degenerated aortic bioprosthesis (P < 0.0001; OR = 20.3). Patients who died at reoperation had higher transvalvular gradients before the primary aortic valve replacement (P = 0.007), received smaller bioprostheses at the first operation (P = 0.03), had later recurrence of symptoms after the first aortic valve replacement (P = 0.04), a higher pre-reoperative New York Heart Association (NYHA) class (P = 0.02), and a higher incidence of coronary artery disease (P = 0.001) and pulmonary artery hypertension (P = 0.009). Endocarditis before the primary aortic valve replacement (P = 0.004), postoperative pneumonia at the first operation (P = 0.005), pulmonary hypertension (P = 0.0004) acquired during the interval, later recurrence of symptoms (P = 0.04) after the first operation, a lower ejection fraction at the time of reoperation (P = 0.03) and acute onset of bioprosthetic regurgitation (P = 0.00002) were predictors for emergency surgery. Higher transvalvular gradients at the primary aortic valve replacement (P = 0.006), coronary artery disease (P = 0.003) acquired during the interval, the need for concomitant coronary artery revascularization (P = 0,001), sex (P = 0.02) and size (P = 0.05) and type of the bioprostheses used (P = 0.007) were incremental predictors for reoperative mortality which were independent of emergency surgery. Conclusions: Elective replacement of failed aortic bioprostheses is safe. Patients undergoing emergency reoperation have a considerably higher mortality. They can be identified by a history of native aortic valve endocarditis, higher transvalvular gradients at primary aortic valve replacement, smaller bioprostheses, and pulmonary hypertension or coronary artery disease acquired during the interval. A failing bioprosthesis must be replaced at its first sign of dysfunction. (C) 2000 Elsevier Science B.V. All rights reserved.