Clinical question: In patients with infective endocarditis, does a vegetation size greater than 10 mm impart a greater embolic risk?
Background: A vegetation size greater than 10 mm has historically been used as the cutoff for increased risk of embolization in infective endocarditis, and this cutoff forms a key part of the American Heart Association guidelines for early surgical intervention. However, this cutoff is derived primarily from observational data from small studies.
Study design: Meta-analysis of observational studies and randomized clinical trials.
Setting: An English-language literature search from PubMed and EMBASE performed May 2017.
Synopsis: The authors identified 21 unique studies evaluating the association of vegetation size greater than 10 mm with embolic events in adult patients with infective endocarditis. This accounted for a total of 6,646 unique patients and 5,116 vegetations. Analysis of these data found that patients with a vegetation size greater than 10 mm had significantly increased odds of embolic events (odds ratio, 2.28; P less than .001) and mortality (OR, 1.63; P = .009), compared with those with a vegetation size less than 10 mm.
Limitations of this research include the potential for selection bias in the original studies, and the inability to incorporate information relating to microbiologic results, antibiotic use, and the location of systemic embolization. Interestingly, as vegetations with a size of exactly 10 mm were variably categorized in the original studies, this meta-analysis was unable to reach a conclusion on the risk of embolic events for instances when vegetation size is equal to 10 mm.
Bottom line: Patients with infective endocarditis and a vegetation size greater than 10 mm may have significantly increased odds of embolic events and mortality, compared with those with vegetation size less than 10 mm.
Citation: Mohananey D et al. Association of vegetation size with embolic risk in patients with infective endocarditis: A systematic review and meta-analysis..
Dr. Winters is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.