Antimicrobial suppressive therapy in prosthetic valve endocarditis rejected from surgery despite indication

Prosthetic valve endocarditis (PVE) incidence is rising in older patients, often rejected for surgery, leading them to a poor prognosis. Optimal antibiotic management is unknown for these patients. We compared the efficacy and safety of suppressive (SAT) versus conventional antimicrobial therapy (CAT) in this setting.

We conducted a prospective, multicentric, cohort study in southwest France including patients with PVE rejected from surgery despite indication, and surviving the initial 6 weeks of intravenous therapy. Beyond this period, patients could or not receive SAT, according to endocarditis team decision. Primary outcome was a composite endpoint of one-year all-cause mortality and PVE-related hospitalization. Secondary outcome was the incidence and nature of SAT-related adverse events.

Between 2012 and 2022, 88 patients were included in the study, 42 receiving SAT and 46 CAT. Mean age was 69.4 ± 16.4 years and patients were highly comorbid (mean Charlson Comorbidity Index 5.6 ± 2.7). Main organisms included Streptococcus spp. (26/88, 29.5%) and Staphylococcus aureus (25/88, 28.4%). The primary composite outcome occurred in 7/42 (16.7%) patients in the SAT group, and 16/46 (34.8%) in the CAT group. Using a Cox model, SAT was significantly and independently associated with a lower incidence of one-year primary outcome (Hazard ratio 0.23, 95% CI 0.08-0.67, P = 0.007). Adverse effects in the SAT group were reported for 6/42 patients (14.3%). These effects were limited, causing only one treatment discontinuation.

In patients with PVE rejected from surgery despite indication, SAT may be safe and associated with better outcomes than CAT.