Mechanical versus bioprosthetic valve for aortic valve replacement: systematic review and meta-analysis of...

The aim of this study was to compare biological versus mechanical aortic valve replacement.

We searched MEDLINE, Scopus and Cochrane Library databases for randomized clinical trials and propensity score-matched studies published by 14 October 2021 according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. Individual patient data on overall survival were extracted. One- and two-stage survival analyses and random-effects meta-analyses were conducted.

A total of 25 studies were identified, incorporating 8721 bioprosthetic and 8962 mechanical valves. In the one-stage meta-analysis, mechanical valves cumulatively demonstrated decreased hazard for mortality [hazard ratio (HR): 0.79, 95% confidence interval (CI): 0.74-0.84, P < 0.0001]. Overall survival was similar between the compared arms for patients <50 years old (HR: 0.88, 95% CI: 0.71-1.1, P = 0.216), increased in the mechanical valve arm for patients 50-70 years old (HR: 0.76, 95% CI: 0.70-0.83, P < 0.0001) and increased in the bioprosthetic arm for patients >70 years old (HR: 1.35, 95% CI: 1.17-1.57, P < 0.0001). Meta-regression analysis revealed that the survival in the 50-70 year-old group was not influenced by the publication year of the individual studies. No statistically significant difference was observed regarding in-hospital mortality, postoperative strokes and postoperative reoperation. All-cause mortality was found decreased in the mechanical group, cardiac mortality was comparable between the 2 groups, major bleeding rates were increased in the mechanical valve group and reoperation rates were increased in the bioprosthetic valve group.

Survival rates seem to not be influenced by the type of prosthesis in patients <50 years old. The survival advantage in favour of mechanical valves is observed in patients 50-70 years old, while in patients >70 years old bioprosthetic valves offer better survival outcomes.