Data on arterial thromboembolism in children undergoing cardiac surgery are limited. We sought to characterise, and estimate rates of, incident and recurrent arterial thromboembolism, and describe antithrombotic therapies for treatment in a large multinational population of children with CHD undergoing cardiac surgery.

We queried the TriNetX global electronic health record (derived real-world data research platform) from 2017 to 2024 for patients less than 18 years of age and an index arterial thromboembolism within 1 year of congenital cardiac surgery. Data were descriptively analysed.

Of 20,102 children who underwent an index cardiac surgery for CHD, 206 (1.1%) developed an index arterial thromboembolism within 1 year of surgery: 111 (53.9%) had only arterial thromboembolism and 95 (46.1%) had concomitant venous thromboembolism. The most common anatomic site for arterial thromboembolism was the lower extremity (n = 141, 68.4%), and the most common surgery was the Glenn procedure (n = 35, 17%). Unfractionated heparin was utilised in 136 (67 %) and aspirin in 91 (44.2%) patients. Recurrent thromboembolism occurred in 36 (17.5%) patients within 1 year of the index thromboembolism.

Among children undergoing congenital cardiac surgery, arterial thromboembolism was rare (1% of patients), but the 1-year risk of recurrent thromboembolism was high, at 17.5%. Multicentre prospective cohort studies are warranted to further evaluate risk factors for recurrent thromboembolism, to facilitate future risk-stratified interventional trials designed to reduce the high thromboembolism recurrence risk in these children.