Aortic prosthetic valve endocarditis: clinical characteristics, microbiological profile and outcomes comparison between transcatheter and surgical bioprosthesis

Background The frequency of prosthetic infective endocarditis (IE) is increasing, accounting for 30% of cases in EURO-ENDO registry. In this registry, Enterococcal IE frequency was higher, compared to previous studies, and culture negative was also more frequent than expected. Furthermore, there was a high number of embolic events that could occur in up to 40% of cases. Mortality is also high, up to 30%. However, most of the studies reported are related to surgical prosthesis and very few is known regarding infection of transcatheter prosthesis. Our objective was to compare clinical characteristics, microbiological profile and outcome between surgical and transcatheter (TAVI) aortic bioprosthesis. Methods We reviewed all transesophageal echocardiograms performed in our institution from 2019 to 2024 for suspicious endocarditis in patients with prosthetic biological valves, either surgically or percutaneously implanted, some of them in other institutions. The electronic records were reviewed and confirmed endocarditis cases were included in the present analysis. Data was collected and this is a descriptive analysis regarding clinical characteristics, microbiological profile and outcomes. Results A total of 33 patients were included in the analysis, 19 with surgical valves and 14 percutaneous. Mean age was 77 ± 9 years, 64% males. Age was higher in the TAVI group (83 ± 7 vs. 72 ± 8 years, p=0.001). The other baseline clinical characteristics were similar between groups. An early endocarditis occurred in 21% of surgical patients and 57% in TAVI patients (p=0.033). The most common finding at echocardiography was the presence of vegetations, but the presence of abscess was observed in 33% of surgical compared to 7% in TAVI (p=0.098). Embolization rate was 42% in surgical and 21% in TAVI (p=0.278). The most frequent bacteria in surgical cases were Streptococcus (26%) and Enterococcus (26%), followed by Staphylococus (21%). In 16%, it was culture-negative. In TAVI patients, the most frequent bacteria were Staphylococcus (21%) and Steptococcus (21%), followed by Enterococcus (14%. However, in 14% it was culture-negative and in 28% of the cases, there were unusual bacteria. One-year all-cause mortality rate was 47% in surgical vs. 64% in TAVI (p=0.335). At a mean follow up of 401 ± 417 days, the mortality rate was 58% in the surgical group and 86% in the TAVI (p=0.086). Conclusions Although this is an exploratory study, from a single-centre and with a limited number of patients, we observed a similar pattern in endocarditis presentation in surgically implanted valves compared to percutaneous. However, early endocarditis was more frequent in percutaneous valve endocarditis, with a trend to a higher mortality rate.