Aortic and Mitral Valve Prostheses Endocarditis: The Optimal Moment for a Successful Surgical Treatment?

Objectives: Despite detailed clinical research, the optimal setting for a prosthetic valve replacement in prosthesis endocarditis is not clear. Preoperative intravenous antibiotic drugs aims to improve the patient conditions for the operation by reducing the germ load. However, the microbiological proof of the germ from the prosthesis is often not possible. The present study focuses on the aspect of the existence of an antibiogram in a retrospectively study. We wanted to know, whether the delay of preoperative antibiotic treatment modulates the postoperative mortality.

Methods: Data of 84 patients with valve prosthesis endocarditis who underwent Redo-AVR or -MVR were analyzed, including 60-day mortality rate and the evaluation of early (≤12 months after prior native valve replacement) versus late (>12 months after prior native valve replacement) incidence. The influence of preoperative conditioning by antibiotic treatment and the absence of an antibiogram were analyzed.

Results: The 60-day mortality rate was 28.6%. Patients with early incidence of valve prosthesis endocarditis seem to have a higher mortality rate than those with late incidence (36.4 vs. 23.9%, p = 0.216). In 32 cases, the postoperative antibiotic treatment was based on the antibiogram for the proven germ and the mortality rate was 31.3% versus 52 cases without any antibiogram nor proven germ and a mortality rate of 23.1% (p = 0.282). The proven germs were divided into five groups: Staphylococcus, Candida, Enterococcus faecalis, Streptococcus, and other germs. Patients with the proof of Streptococcus as well as other germs were 100% survivors (p = 0.015). All patients with Staphylococcus had large abscesses and rings destructions in addition to the typical vegetations.

Conclusion: Prosthetic aortic and mitral valve endocarditis remains a severe challenge in order to find the best treatment. Despite all efforts, the results could not be improved by preoperative antibiotic conditioning. The identification of the germ found at the prosthesis did not improve the results. As prosthetic endocarditis is difficult to discover, the only way to improve the results is an earlier operation based on earlier identification of the endocarditis in order to avoid irreversible destruction of cardiac structure. We conclude that neither the delay of the operation nor the absence of actual germs in the intraoperatively prosthetic preparations seem to affect the postoperative course of these patients significantly.