RIGHT-TO-LEFT INTERATRIAL COMMUNICATIONS AFTER THE MODIFIED FONTAN PROCEDURE - IDENTIFICATION AND MANAGEMENT WITH TRANSCATHETER OCCLUSION

Objective-To describe unusual venous communications from the right to the left atrium resulting in cyanosis after the modified Fontan proced ure, and their management with transcatheter occlusion. Methods-Betwee n September 1999 and November 1994, eight patients were assessed for p ersistent cyanosis after a modified Fontan procedure. Desaturation was found to be caused by unusual venous shunts originating at atrial lev el, and transcatheter occlusion with either a double umbrella or coil was attempted. Results-Three types of venous channels were identified. The first type of communication consisted of thin long tortuous chann els originating from the right atrial wall, and draining into the left atrium through a capillary network. The second type of communication was in the superior anterior portion of the atrial baffle, incorporati ng the pectinate muscles of the right atrium, draining into the neolef t atrium. These channels were shorter and often fanned out into small vessels toward the right atrial appendage. In each instance, the shunt s were in the superior suture Line of a lateral tunnel modification of the Fontan procedure. The third type of communication originated from the inferior vena cava, connecting inferior phrenic veins to pericard ial veins and subsequently to the left atrium, at or close to the osti um of the left pulmonary veins. Before device occlusion, the room air aortic oxygen saturation was 88(SD 4)% (range 84% to 94%), and increas ed to 95(3)% (range 91% to 100%) following occlusion (PL much less tha n 0.001). The mean right atrial pressure was 14(4)mm Hg and remained u nchanged after occlusion. In six patients there was complete shunt obl iteration, while in two both occluded with umbrella devices, a small r esidual leak persisted. No complication occurred during or immediately after catheterisation. Conclusions-Unusual venous communications can evolve after the Fontan procedure, resulting in the development or per sistence of cyanosis. Some of these communications may be present preo peratively as normal veins draining into the right atrium, enlarging w ith the increased atrial pressure after surgery. These observations af fect long term function after the Fontan procedure. Transcatheter occl usion of these communications is technically feasible and effective, a lthough recurrence may occur.