Intracardiac thrombus in adults with the Fontan circulation

Objectives: To determine the treatment and outcomes of a cohort of adults with the Fontan circulation diagnosed with intracardiac thrombus. Background: Formation of thrombus is common after the Fontan operation, albeit little has been published on the treatment and outcomes of these patients once they have developed an intracardiac thrombus. Methods: We identified all patients who had been converted to the Fontan circulation from the cardiology database at the Toronto Congenital Cardiac Centre for Adults, Toronto, and The Royal Brompton Hospital, London, studying the period from 1981 to 2003. We then reviewed the relevant echocardiograms and medical records. Results: Intracardiac thrombus was identified in 28 of 235 patients with the Fontan circulation, the patients having an average age of 27 plus or minus 9 years. Of the patients, 21 were initially medically treated, 19 with heparin or warfarin, and 2 with thrombolysis, whereas 7 patients underwent immediate surgical removal of the clot. Overall mortality was 18%, with residual clots seen in 39% of surviving patients at 1 year of follow up. At presentation, the haemodynamic stability of each patient with intracardiac thrombus dictated initial strategies for management, with 17% of those with stable presentations undergoing immediate surgical treatment, as opposed to 75% of those with unstable presentations (p-value equals 0.04), as well as correlating with ultimate clinical outcome. The rate of death was 8% in haemodynamically stable patients, versus 75% in haemodynamically unstable patients (p value equals 0.01). Conclusion: Formation of intracardiac thrombus is not rare in adults with the Fontan circulation, and carries a significant risk of death, especially in clinically unstable patients. Emphasis on prevention of formation of the clot is warranted.