Prevalence of "silent" pulmonary emboli in adults after the Fontan operation.

<bold>Objectives: </bold>The study was done to determine the prevalence of pulmonary emboli (PE) in asymptomatic adult Fontan patients and to identify the risk factors associated with PE.<bold>Background: </bold>Right atrial thrombi and systemic thromboembolic complications have been reported after the Fontan procedure. However, the frequency of silent PE in this patient population is not known.<bold>Methods: </bold>All consecutive adult Fontan patients attending the adult congenital clinic over a six-month period underwent ventilation-perfusion (VQ) scanning and blood testing for thrombophilia tendency. If the VQ scan showed an intermediate or high probability for PE, a computerized tomography (CT) pulmonary angiogram was performed to confirm the presence of PE.<bold>Results: </bold>Thirty patients (mean age 26 +/- 7 years, 57% men) were included in this study. Five (17%) adult Fontan patients had an intermediate or high probability for PE on VQ scan, all of which were confirmed on CT pulmonary angiography. No patient had a thrombophilia tendency. Pulmonary emboli were not present in any patients (30%) taking warfarin. Late age at time of Fontan operation (19 +/- 6 years vs. 11 +/- 6 years, p = 0.012) and type of Fontan anatomy (p = 0.001) were associated with increased risk of silent PE.<bold>Conclusions: </bold>Seventeen percent of adult patients with Fontan procedure have clinically silent PE. The long-term hemodynamic implications of this with respect to Fontan attrition over time are unknown. Large randomized prospective studies looking at anticoagulation therapy in all Fontan patients are urgently needed. [ABSTRACT FROM AUTHOR]