Background
Repair of TAPVC associated with heterotaxia syndrome still carries a high mortality. Multiple factors are potentially involved, and acquired pulmonary venous obstruction (PVO) after a TAPVC repair may be an important one.

Methods
Retrospective review of patients undergoing repair of TAPVC associated with heterotaxia (H-TAPVC, n=30) and with no other major cardiac or non-cardiac anomalies (Isolated TAPVC, n=63) from 1997.7 to 2007.11.

Results
Normal PV anatomy (having non-obstructive PVs, well-formed confluence, and single vertical vein) was seen in 52/63 (82.4%) of isolated TAPVC, and in 17/30 (56.7%) of H-TAPVC (OR 3.7, p=0.006). In 8 of the H-TAPVCs, PVs were converged to a small confluence, which necessitated an incision extending into the vertical vein, and mixed TAPVCs were seen in 6. Presence of PV anomaly was associated with a higher incidence of PVO (OR 7.0, p=0.03). Reoperation for PVO was invariably seen in the acute postoperative period in isolated TAPVCs (n=10), whereas it occurred constantly up to 3 years in H-TAPVC (n=8), with the interval to reoperation being 0.3±0.3 and 1.2±1.0 years (p=0.012). Three mid-term mortality cases (occurred > 2 years after repair) had acquired PVO.

Conclusions
PV anomaly was more frequently seen in H-TAPVC, and was associated with higher incidence of acquired PVO. The interval to onset of PVO is longer with H-TAPVC. A different mechanism of PVO may be involved in H-TAPVC, such vertical vein constriction, intrinsic obstruction, and orifice constriction caused by atrial enlargement/wall thickening. Modifications such as sutureless pericardial technique may be justified at initial repair.