Epidemiology and Risk Factors of Mycotic Aneurysm in Patients with Infective Endocarditis and the Impact of Its Rupture in Outcomes. Analysis of a National Prospective Cohort

Background Several aspects of the occurrence and management of mycotic aneurysm (MA) in patients with infective endocarditis (IE) have not been studied.Objectives To determine the incidence and factors associated with MA presence and rupture and to assess the evolution of those initially unruptured MA.Methods Prospective multicenter cohort including all patients with definite IE between January 2008 and December 2020.Results Of 4548 IE cases, 85 (1.9%) developed MA. Forty-six (54.1%) had intracranial MA and 39 (45.9%) extracranial MA. Rupture of MA occurred in 39 patients (45.9%). Patients with ruptured MA had higher 1-year mortality (hazard ratio, 2.33; 95% confidence interval, 1.49-3.67). Of the 55 patients with initially unruptured MA, 9 (16.4%) presented rupture after a median of 3 days (interquartile range, 1-7) after diagnosis, being more frequent in intracranial MA (32% vs 3.3%, P = .004). Of patients with initially unruptured MA, there was a trend toward better outcomes among those who received early specific intervention, including lower follow-up rupture (7.1% vs 25.0%, P = .170), higher rate of aneurysm resolution in control imaging (66.7% vs 31.3%, P = .087), lower MA-related mortality (7.1% vs 16.7%, P = .232), and lower MA-related sequalae (0% vs 27.8%, P = .045).Conclusions MA occurred in 2% of the patients with IE. Half of the Mas occurred in an intracranial location. Their rupture is frequent and associated with poor prognosis. A significant proportion of initially unruptured aneurysms result from rupture during the first several days, being more common in intracranial aneurysms. Early specific treatment could potentially lead to better outcomes. In this prospective multicenter cohort with 4,548 infective endocarditis cases, mycotic aneurysms (MA) developed in 2%, with half being intracranial. Rupture was common, correlating with poor prognosis. A notable portion of initially intact intracranial MA ruptured within the initial days.