INCREASING CYANOSIS EARLY AFTER CAVOPULMONARY CONNECTION CAUSED BY ABNORMAL SYSTEMIC VENOUS CHANNELS

Objective-To show that abnormal systemic venous channels in patients w ho undergo cavopulmonary anastomoses can become manifest and haemodyna mically important only after surgery despite detailed preoperative inv estigation. Design-Descriptive study of patients fulfilling the above criteria selected from hospital records over the past three years. Set ting-A tertiary referral centre. Patients-Of the three cases identifie d, two were isomeric, one with left atrial isomerism and hemiazygos co ntinuation of the inferior vena cava who underwent bilateral bidirecti onal Glenn anastomoses and one with right isomerism who underwent tota l cavopulmonary anastomosis. Case 3 had absent left atrioventricular c onnection with a hypoplastic left lung and underwent a classic right G lenn procedure. All three cases presented with progressive cyanosis in the early postoperative period. Interventions and results-Postoperati ve angiography in case 1 showed a remnant of a left inferior vena cava draining to the atrium to have become grossly dilated causing cyanosi s, which resolved after redirection of this vessel and of the hepatic veins into the right pulmonary artery with an intra-atrial baffle. Cya nosis in case 2 was caused by intra-hepatic shunting to a hepatic vein draining to the left of the intra-atrial baffle. The diagnosis was ma de at necropsy, being overlooked on postoperative angiography. Repeat angiography in case 3 showed progressive dilatation of a small left su perior vena cava to coronary sinus. Test occlusion with a view to embo lisation revealed hitherto an undemonstrated hemiazygos continuation o f inferior caval to brachiocephalic vein. The patient underwent surgic al ligation of these two venous channels. Conclusions-Despite appropri ate investigation some ''abnormal'' venous pathways manifest themselve s, dilate, and become haemodynamically important only after surgical c avopulmonary anastomoses. In the presence of early postoperative cyano sis ''new'' systemic venous collateral channels should be considered a s a possible cause, which may require reintervention.