Long-term outcomes of patients undergoing mechanical versus bioprosthetic aortic root replacement

Background We evaluated the impact of valve type (mechanical vs. bioprosthetic) on survival after aortic root replacement (ARR). Methods In a propensity-matched analysis, we evaluated consecutive operations from 2010 to 2018. Patients were identified using a prospectively maintained institutional database. Patients with infective endocarditis were excluded. Kaplan-Meier survival estimation and multivariable Cox regression analysis were performed. Cox regression adjusted for age, sex, baseline comorbidities, and operative variables. Propensity score matching yielded 153 pairs of patients. Results A total of 893 patients were identified. We excluded 192 patients with endocarditis and evaluated 701 patients. Of these patients, 455 (64.9%) received a bioprosthetic valve, 246 (35.1%) received a mechanical valve. Median follow-up was 4.06 years. The proportion of aortic dissections and circulatory arrest as well as cardiopulmonary bypass and ischemic times were similar across groups (p = .207, p = .086, p = .668, p = .454, respectively). Operative mortality was significantly higher in the bioprosthetic valve group (7.9% vs. 2.4%, p = .004). Total length of hospital stay was longer (11.4 +/- 11.0 vs. 9.5 +/- 10.1, p < .001) and there was a higher proportion of prolonged postoperative ventilation >24 h (21.3% vs. 13.0%, p = .007) in the bioprosthetic group. Postoperative outcomes were similar, regarding stroke (p = .077), re-exploration for bleeding (p = .211), new dialysis requirement (p = .077), long-term bleeding complications (p = .561), and reoperations (p = .755). Mechanical valve replacement was associated with improved long-term survival (adjusted HR 0.42, 95% CI: 0.23-0.77, p = .005). Conclusions These findings suggest that mechanical valves for ARRs may confer a survival benefit over bioprosthetic valves. Surgeon bias was likely to account for this survival advantage.