Vegetation Size May Increase Mortality Risk in Infective Endocarditis

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Large vegetations (>10 mm) may be associated with an increased risk of embolization. <i>Photo Credit: CDC/Dr Edwin P. Ewing, Jr.</i>
Large vegetations (>10 mm) may be associated with an increased risk of embolization. Photo Credit: CDC/Dr Edwin P. Ewing, Jr.

Patients with a vegetation size greater than 10mm had increased odds of embolic events and mortality, according to a new study published in JAMA Internal Medicine.

Fragmentation of vegetation specimens or cardiac tissue in patients with infective endocarditis can lead to embolic events in up to 80% of cases. The American Heart Association guidelines recommend the consideration of surgical options when the vegetation size in a patient is greater than 10 mm to prevent the likelihood of an embolic event, but evidence behind these recommendations are based on small observational studies with varying degrees of bias.

In a meta-analysis comprised of studies published on PubMed and EMBASE databases before May 1, 2017, the association of vegetation size greater than 10 mm with embolic events was evaluated. Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines by 2 independent reviewers.

The search inclusion criteria included studies where vegetation size was estimated by 2-dimensional transthoracic endocardiography and/or transesophageal echocardiography, studies of adult patients with native valve infective endocarditis, and studies that provided information on embolic events in patients with a vegetation size less and greater than 10mm. A total of 21 studies published from 1983 to 2016 were included, including both observational studies and randomized clinical trials. These studies had a total of 6646 patients with infective endocarditis along with 5116 vegetations with dimensions.

Increased odds of embolic events were observed in patients with a vegetation size greater than 10 mm compared with patients with a vegetation size less than 10 mm (odds ratio [OR] 2.28; P <.001). The calculated risk difference between these 2 groups was 0.13 (P <.001). Interestingly, studies published from 2006 to 2016 showed an increased likelihood of embolic events with a vegetation size greater than 10 mm (OR 2.70; P <.001), while studies published from 1993 to 1999 showed that patients with and without a vegetation size greater than 10 mm were at comparable odds for embolic events (OR, 1.41; P =.24). No significant difference between these subgroups was found on the basis of age, male sex, or type of valve involved. Additionally, an association between vegetation size greater than 10 mm and all-cause mortality was seen (OR, 1.63; P =.009).

An ambiguity that remains is whether a vegetation size of exactly 10 mm is associated with embolic events as a result of some studies grouping it with vegetation sizes greater than 10 mm and others grouping it with vegetation sizes less than 10 mm.

Based on the results of this analysis, the study authors concluded that “understanding the risk of embolization will allow clinicians to adequately risk stratify patients and will also help facilitate discussion regarding surgery in patients with a vegetation size greater than 10 mm.”

Reference

Mohananey D, Mohadjer A, Pettersson G, et al. Association of vegetation size with embolic risk in patients with infective endocarditis: a systematic review and meta-analysis [published online February 19, 2018].JAMA Intern Med. doi: 10.1001/jamainternmed.2017.8653

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