Infective endocarditis following transcatheter aortic and mitral valve implantation: incidence, predictors and outcomes

Background Transcatheter aortic valve implantation (TAVI) and transcatheter mitral valve implantation (TMVI) are established therapeutic strategies with expanding indications. Infective endocarditis (IE) remains a rare but serious complication associated with high morbidity, in-hospital mortality and diagnostic challenges related to prosthetic imaging. Purpose To evaluate the incidence, determinants, microbiological characteristics and prognosis of IE following TAVI and TMVI. Methods We conducted a single-centre retrospective observational study including all definite or possible IE cases, according to ESC criteria, occurring after TAVI or TMVI between October 2006 and February 2025. Determinants of IE were analysed using Fine and Gray competing risk models, with death as a competing event. Separate univariable and multivariable analyses were performed for the TAVI and TMVI cohorts. Kaplan–Meier analyses were performed to assess overall, endocarditis-free and post-IE survival in both cohorts. Results Among 2,545 patients who underwent TAVI and 237 who underwent TMVI, IE occurred in 72 TAVI patients (76 episodes; 2.8%) and 11 TMVI patients (4.6%). After TAVI, cumulative IE incidence was 1.3% at 1 year and 3.8% at 5 years. Younger age and atrial fibrillation were independently associated with IE, whereas elective procedures were protective. Enteric bacteria accounted for 47.4% of cases, predominantly enterococci (28.9%) and streptococci of gastrointestinal origin (18.4%), followed by staphylococci (19.7%) and oral streptococci (13.2%). The colon was the main portal of entry (22.4%). Embolic events occurred in 44.7% of cases. An intravenous-to-oral antibiotic switch was performed in 20 patients (26.3%), while surgery was performed in only 2 of the 27 patients with a surgical indication (7.7%). In-hospital mortality was 23.7%. After TMVI, cumulative IE incidence was 2.7% at 1 year and 5.1% at 5 years. Staphylococcus aureus predominated (36.4%), frequently associated with catheter-related infection (27.3%). Embolic events occurred in 27.3% of patients. No patient received oral antibiotic therapy, and surgery was performed in only one of the seven patients with a surgical indication (14.3%). In-hospital mortality reached 36.4%. Conclusion IE following TAVI and TMVI remains an uncommon complication but carries a poor prognosis. Microbiological profiles and portals of entry differ according to the procedure, supporting targeted preventive strategies, including antibiotic prophylaxis covering enteric pathogens, rigorous catheter management and screening for oral and dental infectious foci. Given the predominance of a colonic portal of entry, assessment of colorectal cancer screening status prior to TAVI implantation may warrant consideration.