Objective: To assess the surgical results of the Norwood procedure and subsequent clinical outcome in the setting of transposition of the great arteries (TGA) with a dominant morphologic left ventricle.
Methods: Among 486 patients who underwent the Norwood procedure from 1988 to 2007 at our institution, there were 37 patients with TGA and left ventricular dependant circulation with the following associated lesions: double inlet left ventricle (DILV) (n=24), tricuspid atresia (n=9), ventricular septal defect (VSD) with hypoplastic right ventricle (RV) (n=4). Outcomes for all three-staged procedure were compared with the overall Norwood group.
Results: Early mortality was 21.6% (8/37) compared to 26.7% (120/449) in the overall Norwood group (p=ns). There was only one subsequent death giving a 5- and 10-year actuarial survival of 72.8+/-7.4% compared to 55.3+/-2.6% and 52+/-2.9% at 5 and 10 years for the overall series (p=0.06). Median follow-up was 4.7 (0.7-10.2) years. Eighteen patients underwent stage III completion at 3.9+/-1.5 years from the second stage with no mortality. Preoperative mean pulmonary artery (PA) pressure and transpulmonary gradient were respectively 11.6+/-3.4 and 5.2+/-3.3 mmHg. All patients had good left ventricle (LV) function at time of stage III. All patients except one are currently in NYHA I. One patient (with DILV) had congenital heart block and required a pacemaker. There was no postoperative heart block. The systemic outflow was unobstructed in all patients and no patient required any additional intracardiac procedure.
Conclusions: The Norwood procedure provides good palliation in this subgroup of patients and avoids the need for subsequent intracardiac operations, maintaining unobstructed systemic outflow tract and avoiding the risk of postoperative heart block.