Recurrent Thromboembolism in Pediatric Congenital Heart Disease: Cumulative Incidence and Prognostic Factors.

Congenital heart disease (CHD) is a risk factor for thromboembolism (TE). Data describing the rate of, and risk factors associated with, recurrent TE in children with CHD are limited. We prospectively evaluated TE recurrence risk in children with CHD and acute TE and investigated clinical risk factors associated with recurrent TE. Patients < 21 years of age with CHD and acute TE were enrolled in a single-institutional prospective inception cohort study (July 2013-April 2024). Descriptive statistics summarized variables including CHD and thrombus characteristics, antithrombotic regimens, bleeding, and recurrent TE. Multivariable logistic regression determined risk factors for recurrent TE. Among 40 children with CHD and acute TE, 13 (33%) developed ≥ 1 recurrent TE (arterial n = 1 [6%], venous n = 15 [83%], venous + arterial n = 2 [11%]) at a median time of 86 (interquartile range, 45-112) days postdiagnosis of the index TE. One-year cumulative incidence of recurrent TE was 38%. Twelve (67%) recurrent TE events were central venous catheter (CVC)-related. In univariable analyses, immobility (46% vs. 7%, p = 0.01), the presence of a CVC (69% vs. 30%, p = 0.02), and lower extremity index venous TE (89% vs. 41%, p = 0.04) were associated with TE recurrence. After adjustment for other potential risk factors via multivariable logistic regression, immobility (adjusted odds ratio [OR] 13.2, 95% confidence interval [CI] 1.16-151.3, p = 0.04) and the presence of a CVC (adjusted OR 5.28, 95% CI 1.03-27.1, p = 0.05) remained as independent risk factors for recurrent TE. The 1-year risk of TE recurrence was high among pediatric patients with CHD and acute TE. Immobility and the presence of CVC were independent risk factors for recurrent TE. Multicenter prospective cohort studies are warranted to substantiate and expand upon these important findings.