Bioprosthetic versus mechanical prostheses in patients aged 50 to 70 years undergoing aortic valve replacement surgery: outcomes analysis from propensity score matching

Abstract Introduction Despite increasing use of bioprosthetic surgical aortic valve replacement (bAVR) in patients ≤70 years [1, 2], the relative benefits compared to mechanical valve replacement (mAVR) remain uncertain [3, 4]. Purpose The current study aims to compare mortality and other important clinical endpoints by prosthesis type for patients aged 50-70 years who received an AVR in a well-characterised Australian cohort. Methods A retrospective cohort study was designed utilising the WAVES Patient Registry and incorporating linked administrative outcome data including all patients who had an AVR in Western Australian public hospitals between 2010-2020. The primary endpoint was all-cause mortality. Secondary endpoints included cardiovascular (CV) mortality, separately and combined with non-fatal myocardial infarction and non-fatal stroke (MACE), major bleeding, and days alive and out of hospital (DAOH). Outcomes were compared based on a propensity-matched analysis (including demographics, biometrics, and clinical characteristics). Results Within the initial cohort of 727 patients undergoing surgical AVR (mean age = 63 ± SD 6), a propensity-matched cohort identified 151 patients each with bAVR (mean age = 61 ± 4) and mAVR (mean age = 60 ± 5). Patients who received mAVR versus bAVR had improved all-cause survival (Hazard Ratio [HR] 0.50; 95% CI 0.25-0.99) but increased risk of major bleeding (HR 4.85; 95% CI 1.57-14.98). There were no significant differences in CV mortality (HR 0.58; 95% CI 0.19-1.74), MACE (HR 0.59; 95 % CI 0.32-1.07), or DAOH by prosthesis type (P = 0.452). Conclusions Patients aged 50-70 years who underwent mAVR had lower risk of all-cause mortality compared with bAVR, despite higher bleeding risk. Although risks of CV mortality and MACE were lower in mAVR, statistical significance was not reached, likely due to the small sample size. Larger studies are necessary to confirm these findings, which have important clinical implications.