Case report: a thrombus to remember: a case of warfarin non-compliance in a total cavopulmonary circulation patient.

Background: The lack of pulsatile nature of the pulmonary blood flow through total cavopulmonary circulation (TCPC) has shown to prompt endothelial dysfunction thus creating a hypercoagulable state. Patients with a Fontan-type circulation are, therefore, at an increased risk of venous and arterial thromboembolism. In the setting of hypoplastic left heart syndrome following staged surgical repair, subaortic thrombosis is relatively common, but thrombosis of the hypoplastic aortic root is less commonly described. Case summary: Here, we present the case of a 25-year-old male with a background of TCPC and poor adherence to anticoagulation, who presented with features of acute coronary syndrome and was found to have right coronary artery thromboembolism stemming from thrombosis of the aortic root. He was treated with thrombolysis instead of coronary intervention due to the risk of dislodging the aortic root thrombus. He underwent successful thrombolysis and was discharged home thereafter. Discussion: In patients with a Fontan-type circulation and Norwood repair with Damus-Kaye-Stansel anastomosis, rigorous adherence to anticoagulation, and regular specialist follow-up are crucial. This case emphasizes the dire consequences of medication non-compliance in these patients. Effective patient education on the importance of anticoagulation and ensuring compliance through ongoing surveillance in clinic and primary care can be lifesaving in preventing such events.