Discussion
Persistence of the left superior vena cava (LSVC) is the most common anomaly of the systemic venous connection, and in the absence of associated defects may be considered a variant of normal. Its presence can be relevant when a central venous catheter or a transvenous pacemaker is needed. Also, a LSVC can interfere with optimal venous drainage and exposure during some cardiac surgical procedures [1-6]. A persistent LSVC usually drains into the coronary sinus, but sometimes can drain into the left atrium leading to right-to-left shunt. When needed, surgical connection is possible with either intra- or extra-cardiac procedures [1-6]. The few cases reported in literature have been treated with: a) division and re-implantation of the LSVC to right atrium [1,4]; b) an intra-atrial baffle or graft to divert flow from the LSVC to the right atrium and to close the ASD [1, 2, 4, 7]; c) anastomosis of the LSVC to the left pulmonary artery [6,8,9] or d) simple ligation of the LSVC [1, 2, 3, 4-6, 8].
Our patient presented with a combination of persistent LSVC draining into the LA, a large ostium secundum ASD, coronary veins draining into the LA and pulmonary hypertension responding to pulmonary vasodilators. The multiple anomalous connections between the systemic and pulmonary circulation did not translate into a particularly high Qp/Qs, likely due to concomitant presence of left-to-right and right-to-left shunts. However, as fast fibrillation entered the picture the patient decompensated. An interatrial baffle would have been our treatment of choice, but the ostium of the left superior pulmonary vein was at risk of obstruction due to its proximity to the ostium of the LSVC. Therefore, an extracardiac technique was used.
As there is no standardised procedure for the correction of a persistent LSVC draining into the LA, whenever surgery is considered, the choice of the technique should take into account several variables such as the patient’s age, the intra-cardiac anatomy, the size of both the right superior vena cava and the pulmonary artery, the pulmonary vascular resistance and the site of drainage in the left atrium.