Sinus Venosus Atrial Septal Defect: Repair with an Intra-Superior Vena Cava Baffle

Abstract

Although sinus venosus atrial septal defect (ASD) is a relativelysimplecongenitalcardiaclesion,repairshouldbe performed carefully to avoid obstruction of blood flow from the superior vena cava (SVC), associated anomalous rightsided pulmonary veins, or both of these structures. Sinus venosusASDsarelocatedoutsideoftheovalfossaatthepoint of entry of the SVC into the right atrium usually in close proximity to the pulmonary veins draining the right upper lung. 1 Often the right superior and occasionally middle pulmonary veins appear to enter the right atrium close to the SVC orifice; not uncommonly, these veins enter directly into the SVC. A true secundum ASD or patent foramen ovale may also be present. Sinus venosus ASDs without anomalous pulmonary venous drainage may be managed by simple patch closure of the ASD with preservation of SVC blood flow into therightatrium.Inthepresenceofanomalousdrainageofthe pulmonary veins at or above the SVC‐right atrial junction, a number of reconstructive options may be employed for management of these defects. When the entrance of the pulmonary veins is high in the rightatriumwithanadequaterimoftissueattheorificeofthe SVC, simple patch closure of the defect can be performed, taking care to orient the patch to allow unobstructed pulmonary venous return into the left atrium while maintaining unobstructed SVC return to the right atrium. The Warden procedure may be successfully employed in cases where the anomalous pulmonary venous drainage is high into the SVC. 2,3 In this procedure, the SVC is transected above the entry point of the pulmonary veins and the cardiac end of the SVC is oversewn. The SVC orifice is then baffled to the left atrium through the ASD; in this way the SVC orifice effectively serves as a large common orifice for the anomalous pulmonary veins. The reconstruction is completed by anastomosing the distal end of the SVC to the right atrial appendage to reestablish SVC drainage. For sinus venosus ASDs accompanied by anomalous pulmonary venous drainage that enters the SVC just superior to the cavoatrial junction or slightly higher, a pulmonary venous baffle to the ASD can be constructed via an incision in the SVC‐right atrial junction with patch enlargement of the junction. This technique requires precise technical execution toproduceunobstructedSVCandpulmonaryvenousreturn. In addition, it is important to avoid damage to the coronary arterial blood supply of the sinoatrial (SA) node at the time of surgery, which may demonstrate substantial anatomic variability from patient to patient.