Evaluation of the extracardiac conduit modification of the Fontan operation for thrombus formation using magnetic resonance imaging.

BACKGROUND The prevalence of thrombosis after the Fontan procedure depends upon the surgical technique used and the method of detection employed. Current investigations for thrombosis lack sensitivity and specificity or, in the paediatric population, require a general anaesthetic. We undertook a study to examine the feasibility of using magnetic resonance imaging (MRI) to detect thrombosis within the conduit, cardiac chambers and pulmonary arteries after the extracardiac conduit modification of the Fontan procedure. METHODS Of the 50 children who had undergone this procedure at our institution between 1997 and 2002, 26 were eligible for, and 13 underwent, MRI study. The mean age was 10.2 years (range 8.2-16.8 years, median 9.5 years) and the average time from operation was 63 months (range 29-79 months, median 68 months). The mean age at Fontan operation was 4.9 years (range 2.1-10.5 years). Ten were on low dose aspirin, two were on warfarin and one was not anti-coagulated. In all cases, satisfactory imaging of the venous pathways and pulmonary arteries was obtained and there were no thrombi detected. CONCLUSIONS We conclude that MRI is a potentially useful tool for the detection of thrombus in patients who have undergone the Fontan operation.