Modified Norwood procedure with a high-flow cardiopulmonary bypass strategy results in low mortality without late arch obstruction

Objective: The results of our modification of the stage I Norwood procedure, in which we use only autologous tissue to reconstruct the aortic arch, were reviewed. A high-flow, low-pressure cardiopulmonary bypass protocol (with phenoxybenzamine), before and after a period of deep hypothermic circulatory arrest, was used. Methods: Between 1993 and 1999, 59 patients, aged 1 to 353 days (median 4 days) and weighing 1.7 to 6.8 kg (median 3.2 kg), underwent a modified Norwood procedure. The ascending aortic diameter ranged from 1.5 to 8 mm (median 3 mm). The modified Blalock-Taussig shunt was 3 mm in 21 patients (36%) and 3.5 mm or larger in 38 patients (64%). Results: Deep hypothermic circulatory arrest and cardiopulmonary bypass times ranged from 15 to 64 minutes (median 37 minutes) and 44 to 144 minutes (median 88 minutes), respectively. Early postoperative survival was 83%. By univariate analysis, early mortality was associated with an ascending aortic diameter of 2.5 mm or less (P = .01). Weight, circulatory arrest and bypass times, diagnosis (hypoplastic left heart syndrome vs variant), shunt size, and date of the procedure did not affect survival. For a median followup period of 37 months (range 4-63 months), 42 (61%) patients underwent bidirectional cavopulmonary shunts, 10 (17%) had Fontan operations, and 1 patient underwent transplantation after a bidirectional cavopulmonary shunt. Eight patients subsequently died, for a 1-year actuarial survival of 72% (95% confidence interval: 60%-84%). Neoaortic arch obstruction was corrected in 3 patients (5%). Conclusions: At intermediate-term follow-up, our modification of the Norwood procedure together with our perioperative strategies has resulted in acceptable outcomes with a low incidence of neoaortic arch obstruction. Patients with a small ascending aortic diameter have emerged as a high-risk group, but a recent technical modification may improve the outlook for these patients.