Externally mounted versus internally mounted leaflet aortic bovine pericardial bioprosthesis: meta-analysis

Recent studies reported higher-than-expected rates of early structural valve degeneration (SVD) and/or reoperation of externally mounted leaflet aortic bioprosthesis compared with others. This meta-analysis aims to compare the outcomes of bioprostheses with externally versus internally mounted leaflet design in patients who underwent surgical aortic valve replacement (SAVR).

MEDLINE and EMBASE were searched through November 2021 to identify comparative studies investigating outcomes following SAVR with either externally or internally mounted leaflet aortic bioprosthesis. Outcomes of interest were reoperation for SVD or any cause and all-cause mortality.

Our analysis included 15 observational studies that enrolled a total of 23,539 patients who underwent SAVR using externally mounted (n = 9338; 39.7%) or internally mounted leaflet (n = 14,201; 60.3%) bioprostheses. Externally mounted valves consisted of the Trifecta (Abbott, St Paul, MN) (n = 6146) and the Mitroflow (LivaNova, London, UK) (n = 3192), and all internally mounted valves were the Perimount (Edwards Lifesciences, Irvine, CA). Externally mounted valves compared with the Perimount were associated with higher reoperation rates for SVD [hazard ratio (HR) 3.55, 95% confidence interval (CI) 2.67-4.72; P < 0.001] and any cause (HR 9.36, 95% CI 3.70-23.67; P < 0.001). Furthermore, externally mounted valves demonstrated higher all-cause mortalities (HR 1.33, 95% CI 1.13-1.56; P < 0.001).

The present study summarizing updated evidence revealed higher reoperation rates and all-cause mortalities in patients with externally mounted leaflet aortic bioprostheses compared with those with internally mounted design. Choosing the right SAVR valve type is critical part of lifetime management of aortic valve disease.