Intracardiac thrombus formation after the Fontan operation

Objectives: Intracardiac thrombus formation is suspected to be a specific sequela after the Fontan operation and is difficult to determine by means of routine transthoracic echocardiography. The aim of our study was to evaluate the occurrence of intracardiac thrombi in the different types of Fontan modifications and to identify predisposing risk factors. Methods: We evaluated 52 patients who had undergone a Fontan-type operation and were free of symptoms regarding thrombosis as determined by transesophageal echocardiography. Results: In 17 (33%) patients thrombus formation could be found without clinical evidence of thromboembolic complications. Neither underlying morphologic disease nor age at operation, type of Fontan operation, sex, follow-up interval, arrhythmias, or laboratory or hemodynamic findings could be identified as predisposing risk factors. Conclusion: In patients having had a Fontan operation with inadequate or without anticoagulation medication, we would recommend routine transesophageal echocardiography to exclude eventual thrombi. Because of the high incidence of thrombi, we suggest oral anticoagulation therapy in all patients.