Intermediate-term outcomes of deferred Norwood strategy

Abstract

Objective: The aim of this study was to assess outcomes of the deferred Norwood strategy, i.e. planned Norwood following routine bilateral pulmonary artery banding and ductal stenting or continuous prostaglandin E1 administration.

Methods: Forty-five patients with hypoplastic left heart syndrome and its variants treated with the deferred Norwood strategy between 2012 and 2021 were enrolled. Mid-term outcomes were retrospectively reviewed. The median follow-up period after Norwood in hospital survivors was 4.6 years (interquartile range: 1.9, 6.8).

Results: Fourteen patients (31.1%) had no risk factors. The median age and weight at Norwood were 1.8 months (0.9, 3.5) and 3.1 kg (2.7, 3.6). Transplant-free survival at 6 years was 84.5%. Birth weight ≤2.5 kg and systemic atrioventricular valve (SAVV) regurgitation ≥ moderate after birth were not risk factors for mortality; body weight at Norwood ≤2.5 kg, however, was a risk factor [hazard ratio (HR), 11.3; 95% confidence interval (CI), 1.2-11; P = 0.036]. Twenty-two (48.9%) underwent Fontan with no mortalities, and 7 (15.5%) are awaiting Fontan. Freedom from SAVV surgery at 5 years was 53.1%. SAVV regurgitation ≥ moderate after birth was a risk factor for SAVV surgery (HR, 16; 95% CI, 3.6-71; P < 0.001); however, ductal stenting had a protective effect against SAVV surgery (HR, 0.09; 95% CI, 0.01-0.68; P = 0.019). Freedom from both surgical and catheter-based pulmonary artery intervention at 3 years was 27.1.

Conclusions: Although deferred Norwood provided acceptable intermediate-term survival, the Fontan completion rate was unsatisfactory. SAVV surgery and pulmonary artery intervention were frequently required.

Keywords: Hybrid stage I palliation; Hypoplastic left heart syndrome; Norwood.