Tetralogy of Fallot without the infundibular septum–restricted growth of the pulmonary valve annulus after annulus preservation may render the right ventricular outflow tract obstructive

Objective Tetralogy of Fallot (ToF) with infundibular septal deficiency (ISD) is commonly associated with postoperative right ventricular outflow tract obstruction (RVOTO), presumably caused by subpulmonary extension of ventricular septal defect (VSD) and restricted growth of the pulmonary valve annulus (PVA). We sought to determine the postoperative growth of the PVA after annulus preservation according to the presence or absence of the infundibular septum. Methods A retrospective review of 90 patients who underwent surgical repair of ToF between June 1997 and August 2008 was performed. Median age at operation was 9.5 months. Infundibular septum was absent in 15 (15/90, 17%). PVA was preserved in 71 patients (71/90, 79%), including 13 patients with ISD (13/15, 87%). Results Median follow-up duration was 39 months (2 months to 13 years). There was no early mortality and one late noncardiac death. Among the patients with PVA preservation, reoperation for RVOTO was performed in 4 patients (4/71, 6%), including 3 patients without the infundibular septum. ISD was identified as the only risk factor in reoperation for RVOTO after PVA preservation (RR: 21.85, P = .007). Among the patients who underwent repair with PVA preservation during infancy (n = 43), PVA (Z-score) increased postoperatively in patients with the infundibular septum (+ 0.021/month, P = .009), whereas the changes in PVA (Z-score) were nonsignificant in patients with ISD (-0.021/month, P = .306), with a marginal intergroup difference ( P = .056). Conclusions PVA preservation in ToF with ISD may be associated with a higher risk for postoperative RVOTO, which can be attributed to the restricted growth of the PVA.