Persistent left superior vena cava: Review of embryologic anatomy and considerations for cardiopulmonary bypass.

The purpose of this report is to alert the perfusionist to the anatomy of persistent left superior vena cava (PLSVC) and the intraoperative complications that this anomaly may present. The perfusionist should be able to devise a venous circuit that will accommodate three cannulae. He should also be aware that, during cardiopulmonary bypass, a copious volume of deoxygenated blood from the left heart sump, with simultaneous cerebral congestion, may signal the presence of undocumented PLSVC.