Commentary: It's better to be alone than in bad company…at least for bioprosthesis

Abstract

Differential benefits and risks with the use of bioprostheses and mechanical aortic valves are an issue of debate, and any large registry data that address these issues are always novel and welcome. Rodriguez-Caulo and colleagues 1 evaluated survival and major adverse cardiac events as primary outcomes in a large registry that included 50-to 65-year-old patients who underwent isolated aortic valve replacement (AVR) from 2000 to 2018 at 27 hospitals in Spain. Propensity matching (2:1) yielded 1822 patients with a mechanical prosthesis and 911 patients with a bioprosthesis. After a median of 6-8 years, survival was similar between both groups. Patients with a mechanical prosthesis had a higher risk for bleeding, and patients with a bioprosthesis had a higher risk for reintervention. 1 When evaluating long-term survival in patients with a bioprosthesis versus mechanical prosthesis through retrospective studies, it is critical to distinguish if included patients underwent isolated AVR or not. Patients aged 50-65 years who require coronary artery bypass grafting (CABG) might receive a mechanical prosthesis to avoid reintervention with patent grafts. This portrays a strong selection bias difficult to adjust by propensity match. Kyt€ o and colleagues 2 recently showed that 10-year allcause mortality was higher in patients with a bioprosthesis in a retrospective study. Although the 10-year mortality in those with a mechanical valve in the study by Kyt€ o and colleagues 2 (18.6%) was similar to that in the study by Rodriguez-Caulo and colleagues 1 (17%), this was not the case for the bioprosthesis (27.6% and 19%,