The association between vegetation size and surgical treatment on 6-month mortality in left-sided infective endocarditis.

Aims In left-sided infective endocarditis (IE), a large vegetation >10mm is associated with higher mortality, yet it is unknown whether surgery during the acute phase opposed to medical therapy is associated with improved survival. We assessed the association between surgery and 6-month mortality as related to vegetation size. Methods and results Patients with definite, left-sided IE (2008-2012) from The International Collaboration on Endocarditis prospective, multinational registry were included. We compared clinical characteristics and 6-month mortality (by Cox regression with inverse propensity of treatment weighting) between patients with vegetation size <= 10mm vs. >10mm in maximum length by surgical treatment strategy. A total of 1006 patients with left sided IE were included; 422 with a vegetation size <= 10mm (median age 66.0 years, 33% women) and 584 (median age 58.4 years, 34% women) patients with a large vegetation >10 mm. Operative risk by STS-IE score was similar between groups. Embolic events occurred in 28.4% vs. 44.3% (P < 0.001), respectively. Patients with a vegetation >10mm was associated with higher 6-month mortality (25.1% vs. 19.4% for small vegetation, P = 0.035). However, after propensity adjustment, the association with higher mortality persisted only in patients with a large vegetation >10mm vs. <= 10 mm: hazard ratio (HR) 1.55 (1.27-1.90); but only in patients with large vegetation managed medically [HR 1.86 (1.48-2.34)] rather than surgically [HR 1.01 (0.69-1.49)]. Conclusion Left-sided IE with vegetation size >10mm was associated with an increased mortality at 6 months in this observational study but was dependent on treatment strategy. For patients with large vegetation undergoing surgical treatment, survival was similar to patients with smaller vegetation size.