Prosthetic Valve Endocarditis After Aortic Valve Replacement: Differences Between Biological and Mechanical Prostheses

Aims Prosthetic valve endocarditis (PVE) is the most severe form of infective endocarditis associated with a high mortality rate. Whether PVE affects biological and mechanical aortic valves to the same extent remains controversial. This study aimed to compare the incidence of re-intervention because of PVE between bioprosthetic and mechanical valves. Methods Patients undergoing isolated surgical aortic valve replacement (AVR) or combined AVR in a single cardiac surgery centre between January 1998 and December 2019 were analysed. All patients who underwent re-intervention because of PVE were identified. The primary endpoint was the rate of explants. Freedom from re-intervention and variables associated with re-intervention were analysed using Cox regression analysis including correction for competing risk. Results During the study period, 5,983 aortic valve prostheses were implanted, including 3,620 biological (60.5%) and 2,363 mechanical (39.5%) prostheses. The overall mean follow-up period was 7.365.3 years (median, 6.5; IQR 2.9-11.2 years). The rate of re-intervention for PVE in the biological group was 1.5% (n=54) compared with 1.7% (n=40) in the mechanical group (p=0.541). Cox regression analysis revealed that younger age (HR 0.960, 95% CI 0.942-0.979; p,0.001), male sex (HR 2.362, 95% CI 1.384-4.033; p=0.002), higher creatinine (HR 1.002, 95% CI 0.999-1.004; p=0.057), and biological valve prosthesis (HR 2.073, 95% CI 1.258-3.414; p=0.004) were associated with re-intervention for PVE. After correction for competing risk of death, biological valve prosthesis was significantly associated with a higher rate of reintervention for PVE (HR 2.011, 95% CI 1.177-3.437; p=0.011). Conclusions According to this single -centre, observational, retrospective cohort study, AVR using biological prosthesis is associated with re-intervention for PVE compared to mechanical prosthesis. Further investigations are needed to verify these findings.