Thromboembolic complications after Fontan procedures: comparison of different therapeutic approaches

Background. Although patients after Fontan procedure have a high incidence of thromboembolic complications, anticoagulant therapy is not handled uniformly. We analyzed the frequency and clinical relevance of thromboembolism after Fontan procedure and compared different therapeutic approaches. Methods. From 1986 to 1998, 101 patients (mean age, 7.3 ± 8.1 years) underwent Fontan type procedure (modified Fontan, N = 40; total cavopulmonary connection, N = 61). In 85 of 87 survivors, transthoracic echocardiography was performed; and in 31 transesophageal echocardiography and/or angiography was performed. Mean follow-up was 5.7 ± 3.5 years. Three groups with different anticoagulant regimen were compared: group I without medication (n = 45), group II with acetylsalicylic acid therapy (n = 14) and group III with Coumadin (n = 26). Results. Thromboembolic events occurred in 13 of 85 patients (15.3%; 3.3 events/100 patient-years). Type of operation as well as other known risk factors had no influence on the rate of thromboembolism. Within the first postoperative year, seven of 13 events occurred. A second peak developed beyond 10 years of follow-up. Patients benefit significantly from Coumadin compared with those who did not receive any medication, with similar results in the entire population and the subgroup of patients with total cavopulmonary connection (log-rank, p = 0.031 and p = 0.033, respectively). With 4.2 events/100 patient-years, the cumulative event rate was substantially higher in group I than with 1.6 in group II and with 1.1 in group III. No relevant bleeding complications occurred. Conclusions. Thromboembolism is frequent after Fontan procedure, with a peak during the first postoperative year and another peak beyond 10 years of follow-up. Coumadin is the most effective prophylactic therapy in preventing thromboembolism. Therefore, we suggest initial oral anticoagulation therapy in patients with Fontan type operation.