Background. It is known that systemic venous collaterals develop and that they can lead an unanticipated cyanosis after the Fontan procedures. However, there have been a few reports focusing on this problem.
Objective. To determine the incidence, clinical course and factors associated with venous collaterals after the Fontan procedures.
Methods. We reviewed angiograms and clinical data in 171 Fontan patients who underwent cardiac catheterization. Venous collaterals with < 95 % systemic desaturation were defined as significant. Anatomic and hemodynamic variables as the predictive factors were compared between the groups with or without decompressing venous collaterals.
Results. Fifty-four venous collaterals were identified in 36 patients (21%). In 19 patients (53%), the collaterals were detected within 1 year after the Fontan procedures. The follow-up catheterizations (n=25) showed that the arterial oxygen saturation at rest (90±4%) did not change during follow-up periods (5.3±3.3 years), although the size of vessels increased in some cases. The morphology of ventricle, hemodynamic variables including pulmonary artery pressure, resistance, Nakata index before the Fontan procedures and transpulmonary pressure after the procedures were similar between the groups. The only anatomic factor of heterotaxia syndrome was a predictor for venous collaterals (53% in heterotaxia vs. 22% in non-heterotaxia, p<0.001).
Conclusions. Systemic venous collaterals are common in the Fontan patients. They increase in size but do not hemodynamically deteriorate with time. These collaterals are more likely to occur in the heterotaxia syndrome.