The effect of adjunctive antibiotic oral therapy on the recurrence of infective endocarditis after valve surgeries.

Adjunctive oral antibiotics following intravenous antibiotics are administered after valve surgery in some patients with active infective endocarditis (IE); however, little is known about their efficacy. Therefore, we evaluated the effect of adjunctive antibiotic oral therapy after IE surgeries. Between 2009 and 2017, 585 patients underwent valve surgery for left-sided active IE at 14 hospitals. Patients who died during hospitalization or transferred with intravenous antibiotics were excluded. Of the remaining 460 patients, 239 were treated with oral antibiotics at discharge (group O) and 221 did not take the oral antibiotic (group N). The primary outcome was all-cause mortality. Secondary outcomes were the recurrence of IE and a subset analysis of it. The two groups had similar background, postoperative inflammatory responses, and an almost similar duration of postoperative intravenous antibiotics. The overall survival rates at 1 and 5 years were 96% and 88% in group O and 92% and 84% in group N, respectively (p=0.425). The rates of freedom from the recurrence of endocarditis at 1 and 5 years were 98% and 94% in group O and 97% and 93% in group N, respectively (p=0.309). In chronic hemodialysis patients, the rates of freedom from the recurrence were significantly higher in group O than in group N (1 year: 100% vs 87.5%; 5 years: 95% vs 69%, p=0.022). Adjunctive oral antibiotics following intravenous antibiotics in patients with active IE after valve surgery did not affect the overall survival and recurrence of IE, except in chronic hemodialysis patients.