Increasing cyanosis early after cavopulmonary connection caused by abnormal systemic venous channels

Abstract

Objective-To show that abnormal systemic venous channels in patients who undergo cavopulmonary anastomoses can become manifest and haemodynamically important only after surgery despite detailed preoperative investigation. Design-Descriptive study of patients fulfilling the above criteria selected from hospital records over the past three years. Setting-A tertiary referral centre. Patients-Of the three cases identified, two were isomeric, one with left atrial isomerism and hemiazygos continuation of the inferior vena cava who underwent bilateral bidirectional Glenn anastomoses and one with right isomerism who underwent total cavopulmonary anastomosis. Case 3 had absent left atrioventricular connection with a hypoplastic left lung and underwent a classic right Glenn procedure. All three cases presented with progressive cyanosis in the early postoperative period. Interventions and results-Postoperative angiography in case 1 showed a remnant of a left inferior vena cava draining to the atrium to have become grossly dilated causing cyanosis, which resolved after redirection of this vessel and of the hepatic veins into the right pulmonary artery with an intra-atrial baffle. Cyanosis 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 made at necropsy, being overlooked on postoperative angiography. Repeat angiography in case 3 showed progressive dilatation of a small left superior vena cava to coronary sinus. Test occlusion with a view to embolisation revealed hitherto an undemonstrated hemiazygos continuation of inferior caval to brachiocephalic vein. The patient underwent surgical ligation of these two venous channels. Conclusions-Despite appropriate investigation some "abnormal" venous pathways manifest themselves, dilate, and become haemodynamically important only after surgical cavopulmonary anastomoses. In the presence of early postoperative cyanosis " new" systemic venous collateral channels should be considered as a possible cause, which may require reintervention.