Aortopulmonary collateral flow in the Fontan patient: Does it matter?

Background. The effects of aortopulmonary collaterals (APCs) on the outcome of a Fontan procedure are unclear. We undertook this study to define the i ncidence and extent of APC flow, identify risk factors for APC flow, and de termine if APC flow has a measurable effect on the outcome of a Fontan proc edure. Methods. The APC flow was directly measured in 32 patients undergoing Fonta n procedures from July 1997 to September 2000. The APC flow was measured in the operating room during total cardiopulmonary bypass, and was expressed as a percentage of total bypass pump flow. Results. The APC flow ranged from 9% to 49% of total pump flow (median, 18% ). Higher preoperative systemic oxygen saturation, pulmonary artery oxygen saturation, pulmonary to systemic flow ratio, and angiographic APC grade co rrelated with higher APC flow. There were no operative deaths; there was on e Fontan takedown (APC flow = 14%). The APC flow had no significant effects on postoperative Fontan pressure, common atrial pressure, transpulmonary g radient, duration of effusions, or resource utilization after the Fontan pr ocedures. Conclusions. In patients undergoing a Fontan procedure, APC flow is omnipre sent, although its extent varies widely. Increased APC flow has no signific ant effect on the outcome of a Fontan procedure. This conclusion applies to patients who are well prepared for a Fontan procedure, but may not extend to patients at higher risk. (C) 2001 by The Society of Thoracic Surgeons.