Outcome in patients with left-sided native-valve infective endocarditis and isolated large vegetations

Background: In patients with left-sided native-valve infective endocarditis (IE), the risk of embolism is increased with a vegetation size ≥10 mm. For this reason-according to guidelines-surgery may be considered in patients with isolated large vegetations (without any other indication for surgery). However, the value of surgery in this patient subset has never been systematically studied.

Hypothesis: We hypothesized that surgery may be superior to medical therapy in terms of clinical outcome in the aforementioned patients.

Methods: All patients who presented at our institution between January 2000 and July 2012 with isolated leftsided native-valve IE and large vegetations (≥10 mm) were examined. Patients with conventional indications for surgical treatment were excluded. Follow-up for clinical events was performed according to predefined definitions.

Results: A total of 71 patients with left-sided native-valve IE and isolated large vegetations qualified for inclusion into the study cohort. Mean vegetation length was 17±5 mm. A total of 59 patients underwent surgery after a mean of 5±6 days following the initiation of antibiotic treatment. Mean follow-up duration was 6.0±2.9 years. Surgical compared to purely medical treatment was associated with a significant increase in long-term all-cause mortality (P = 0.03 by log-rank test, unadjusted analysis). Upon multivariable Cox regression analysis, surgical treatment, affection of mitral valve, blood cultures positive for Staphylococcus aureus, and increasing age showed trends as independent predictors of long-term mortality.

Conclusions: Surgical treatment in patients with left-sided native-valve IE and isolated large vegetations without any other indication for surgery seems to be associated with excess mortality. A randomized controlled trial of surgery vs conservative treatment in this subset of patients is justified.