Clinical characteristics, treatment strategies, and outcomes of patients with aortic valve infective endocarditis with and without aortic root abscess: Insights from the NIDUS registry

Abstract Background Aortic root abscess is a severe and diagnostically challenging complication of infective endocarditis. Aims to examine differences between IE patients with and without aortic root abscesses in patient characteristics, treatment strategies, and clinical outcomes. Methods/results We conducted nationwide, unselected, registry-based cohort study using NatIonal Danish endocarditis stUdieS registry. All patients with aortic valve endocarditis in Denmark from 2016–2021 were included. Clinical and microbiological characteristics, treatment, and mortality were compared according to status of aortic root abscess. Mortality was adjusted for clinically relevant covariates. The study population included 1,902 patients with aortic endocarditis, of whom 316 (17%) had an aortic root abscess. Patients with an abscess versus those without were significantly younger (median 71.5 vs. 75.1 years, p-value=<0.001), more often male (76.3% vs. 69.7%, p-value=0.02), prosthetic valve (50.0% vs. 30.4%, p-value=<0.001), AV-block (10% vs. 1.7%, p-value=<0.001), coagulase-negative staphylococci and streptococci in their blood cultures, and were surgically treated (59.5% vs. 16.1%). In multivariable Cox regression, patients with abscesses had significantly higher 1-year mortality rate compared with those without (HR 1.41, 95% CI:1.13–1.76). When stratifying for surgery, non-operated patients with an abscess had the highest 1-year mortality 55.4%, alongside a high pre-operative risk (median age 79, 38% not self-reliant, more comorbidities including 12% active cancer). Conclusion Aortic root abscess was present in 17% of patients with aortic valve endocarditis and was associated with distinct clinical and microbiological characteristics, a higher frequency of complications, greater prevalence of surgery albeit a higher mortality rate compared with those without an abscess.