Original article: cardiovascular
Evolving strategies and improving outcomes of the modified Norwood procedure: a 10-year single-institution experience

https://doi.org/10.1016/S0003-4975(01)02795-3Get rights and content

Abstract

Background. This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience.

Methods. A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought.

Results. Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors.

Conclusions. With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

Section snippets

Material and methods

Permission to perform the health record review was obtained from the Research Ethics Board of The Hospital for Sick Children. The cardiovascular surgery database was reviewed for all patients having a stage-one Norwood operation between 1990 and 2000. The 10-year period was divided into three eras: era I, 1990 through 1993; era II, 1994 through 1997; and era III, 1998 into 2000.

From March 1990 to October 2000, 171 modified Norwood procedures were performed at The Hospital for Sick Children in

Results

A flowchart of the outcomes for the 171 neonates and infants having a modified Norwood procedure is shown in Figure 1. The overall hospital mortality rate for stage one palliation was 41% and did not differ between patients with a diagnosis of HLHS (mortality rate of 42%, 50/118) versus those with a diagnosis that was not HLHS (mortality rate of 36%, 19 of 53) (p = 0.50). Overall Kaplan-Meier survival is shown in Figure 2. The mortality rate for the stage-one procedure in the three

Mortality

The mortality rate after the stage-one modified Norwood procedure has been reported to be as high 40% to 50% 4, 6. With increased experience, survival has improved to 70% to 80% 6, 9, 10. In our experience, the overall unadjusted mortality rate is 40%. However, it has declined progressively, and in 2000 was 10%.

Risk factors for mortality

Reported risk factors for mortality include earlier era of operation 6, 9, older age at operation 6, 9, lower weight at operation 4, 6, anatomic subtype 2, 3, 14, diagnosis of HLHS

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