Unusual Causes of Late Right Heart Dilatation Long After Repair of Total Anomalous Pulmonary Venous Drainage
Total anomalous pulmonary venous drainage (TAPVD) is an uncommon congenital cardiac condition in which there is no connection between the pulmonary veins (PVs) and the left atrium (LA). The PVs form a confluence behind the LA that usually drains to a systemic vein such as the left innominate or right superior vena cava (supracardiac TAPVD), the portal venous system (infracardiac TAPVD), or the coronary sinus. TAPVD is treated surgically by creating an anastomosis between the pulmonary venous confluence and the LA, closing the (obligatory) atrial septal defect (ASD), and ligating any connection between the pulmonary and systemic veins. The most common reported long-term complication of TAPVD repair is pulmonary venous obstruction, which requires reoperation in 12% to 15% of cases. We present 2 patients in whom unusual causes of persistent right heart dilation were discovered many years after TAPVD repair.
The first patient underwent neonatal repair of supracardiac TAPVD. At the operation, the pulmonary venous confluence was found to drain via a large vein into the superior vena cava. A routine transthoracic echocardiogram performed 14 years after repair showed dilatation of the right ventricle (RV). There was minimal tricuspid regurgitation, and it was not possible to reliably estimate pulmonary artery pressure. At transesophageal echocardiography, only the right upper and left upper PVs were identified draining into the pulmonary venous confluence, but no cause of RV dilatation was positively identified. At cardiac catheterization, drainage of the right lower PV to the portal system was suspected. A subsequent cardiac magnetic resonance imaging scan demonstrated that the superior right and left PVs drained to the LA, a vertical vein connected the pulmonary venous confluence to the portal vein, and the inferior right and left PVs drained to the vertical vein (Figure 1 and Movie I in the online-only Data Supplement). The RV end-diastolic volume was 128 mL/m2 body surface area (upper limit of normal, 110 mL/m2),1 and the estimated ratio of pulmonary to systemic flow (Qp:Qs) was 1.3.
In ≈10% of TAPVD cases, there are pulmonary venous connections to >1 site. In this case, the infracardiac connection, which originally coexisted with the supracardiac connection, had not been recognized at the original operation. Infracardiac connections through the portal system generally present higher resistance to flow than supracardiac connections, and it is likely that at the time of surgery there was relatively little infracardiac flow. Nevertheless, the persistent infracardiac connection provided a route for continued left-to-right shunting and consequent right heart dilatation. The RV dilatation resolved after device occlusion of the vertical vein (Movie II in the online-only Data Supplement).
The second patient underwent repair of supracardiac TAPVD, in which the pulmonary venous confluence was connected to the innominate vein at 1 week of age. After a period of loss to follow-up and 2 uneventful pregnancies, routine echocardiography at 22 years of age showed RV dilatation, a possible residual ASD, and an apparent structure descending from the LA. There was mild tricuspid regurgitation, and the estimated pulmonary artery systolic pressure was 30 mmg Hg to 35 mm Hg. To clarify the anatomy, a cardiac magnetic resonance imaging scan was performed. This confirmed severe RV dilatation (179 mL/m2) with an estimated Qp:Qs of 2 and revealed the cause to be a 13×14-mm inferior sinus venosus ASD (Figure 2), for which surgical repair is planned. Sinus venosus ASDs account for between 5% and 10% of all ASDs, and inferior sinus venosus defects account for only a small proportion of all sinus venosus defects. As far as we are aware, the presence of an inferior sinus venosus ASD has not been described previously in repaired TAPVD.
In both of these cases of repaired TAPVD, magnetic resonance imaging was critical in establishing the mechanisms responsible for RV dilatation. It would seem reasonable that this noninvasive modality be used early in the investigation of similar cases.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.112.113241/-/DC1.
- © 2013 American Heart Association, Inc.