Atrial thrombus after the Fontan-operation: predisposing factors, treatment and prophylaxis

Thrombosis of the right side of the heart has previously been a rarely reported early or late postoperetive complication after a modified Fontan-procedure. In 4(5.5%) of 72 surviving patients who underwent a total cavopulmonary connection for various forms of univentricular atrioventricular connection or other complex lesion a thrombus within the right atrium was diagnosed by transthoracic echocardiogaphy either early (in 3 cases) or late (in one cases) postoperatively. Predisposing haemodynamic abnormalities could be identified in all four patients, but no patient was found to have severe abnormalities of coagulation. Two patients presented with acute clinical symptoms on the third and twelfth day after initial surgery. They underwent emergency reoperation with thrombectomy followed by prophylactic treatment with coumadin or aspirin after initial heparinization. In the other 2 patients, routine postoperative echocardiography revealed a right atrial thrombus without specific clinical symptoms 25 days or 3 months postoperatively. Thrombolytic therapy with an initial bolus of tissue plasminogen activator (0.1 mg/kg) followed by continuous infusion (1 mg/kg/day) combined with heparinization yielded complete resolution of the thrombus after 27 and 40 hours, respectively, as demonstrated on follow-up echocardiograms. Our own experience, coupled with a review of the literature, indicate that prophylactic anticoagulation therapy with coumadin should continue for at least 4 to 6 months for patients with an increased risk for postoperative thrombosis. For infants and young children with a low risk for postoperative thrombosis, aspirin should be given routinely for 6 months postoperatively.