Vegetation size: a key metric in the team effort for treating infective endocarditis

This editorial refers to ‘Prognostic impact of vegetation size in infective endocarditis’, by S. Tadimi-Tazi et al., https://doi.org/10.1093/ehjci/jeag061. Infective endocarditis (IE) remains a lethal disease where surgery, along with antibiotics, is the cornerstone of the treatment strategy.1,2 Echocardiography serves as the main modality in the workup of IE where size of vegetation is a key measure for the evaluation of surgical indication. Vegetation size serves as a factor for risk stratification where previous studies have unfolded that increasing vegetation size has been associated with increased risk of emboli and elevated mortality.3–5 In the absence of heart failure or an abscess, vegetation in effect becomes the key metric for establishing surgical indication. A metric with significant variation in measurement and definition. Hence, it is important to have solid data from large, and preferably unselected cohorts, in order to build confidence in surgical indication guidelines. With the 2023 European Society of Cardiology (ESC) guidelines, even smaller vegetations now suggest surgery, and this is an obvious call for meticulous studies. In the recent issue of the European Heart Journal—Cardiac Imaging, Tadimi-Tazi et al. bring new data to the field with the largest cohort, thus far, to examine the prognostic impact of vegetation size in patients with IE.6 From a multicentre, national registry, recruiting from 44 sites (70% referral centres) in Spain, the authors examined 5000 patients (and 3592 patients with vegetation size measurements) and found that patients with a vegetation ≥10 mm were associated with an increased risk of emboli (odds ratio 1.34, 95% CI: 1.15–1.55) as compared with patients with a vegetation 10 mm without heart failure or uncontrolled infection of which 50.4% underwent surgery and 49.6% of patients were conservatively managed. The authors found that patients undergoing surgery had an in-hospital mortality of 18.6% while this was 11.6% for patients conservatively managed (P = 0.251).10 Future trials will help us provide more clarity in the field, where CHIRURGENDO (NCT03718052) and the ASTERIx trial (NCT05061355) randomize patients with left-sided IE and a vegetation size ≥10 mm, without a class I indication for surgery, to surgery or conventional treatment. In the CHIRURGENDO the primary outcome is a composite of all-cause death and clinically symptomatic embolic events within 6 weeks from randomization while the primary composite endpoint in the ASTERIx trial is death, stroke, or systemic embolism, new IE event, or heart failure hospitalization within 12 months of randomization. The current findings by Tadimi-Tazi et al. should be interpreted in the light of some limitations, which have also been described by the authors. The cohort was mainly represented by patients from tertiary centres that may provide a referral bias with patients not generalized to the overall IE-patient group. The authors identified 5000 patients with a vegetation, but only 3592 patients had vegetation size measurement. Additionally, vegetation size measurements were not provided by a core laboratory which may introduce a large variance across echocardiographers and centres. The authors chose to pool right- and left-sided IE that constitute different entities of the disease with different clinical decision processes. The findings provided by Tadimi-Tazi et al. also show that prognosis according to vegetation size is dependent on localization (right- and left-sided), and future studies should consider only to report findings according to localization. Finally, as acknowledged by the authors, missing data is significant in this study, and the results should be interpreted in the light of this. Taken together, with the limitations of the study, Tadimi-Tazi et al. bring important data, from a large cohort, for the building evidence of vegetation size as a key measure in the workup and clinical decision-making of patients with IE. The authors conclude that vegetation size ≥10 mm was associated with increased risk of mortality and emboly and that ‘Our findings suggest the need for more aggressive management strategies in patients with large vegetations’. However, we strongly believe that only future randomized controlled trials will tell us how aggressive these patients should be treated. Lauge Østergaard (Conceptualization, Methodology, Project administration [equal], Writing—original draft [lead]), and Emil Fosbol (Conceptualization, Methodology [equal], Project administration, Resources, Supervision, Writing—review & editing [lead]) No funding was obtained for this work. No data were used for the preparation of this manuscript.