Volume–Outcome Relationship of Norwood Procedures: Insights from the National Pediatric Cardiology–Quality Improvement Collaborative Database

Abstract

Background

Prior investigations of the center-specific case volume on outcomes in hypoplastic left heart syndrome have conflicting results. This study utilized the National Pediatric Cardiology–Quality Improvement Collaborative registry to investigate the center volume–outcome relationship in patients after the Norwood procedure with consideration of preoperative high-risk features.

Methods

Between 2016 and 2023, centers were categorized by Norwood procedure volume into low- (≤5 cases/y), medium- (6 to 10 cases/y), and high-volume centers (>10 cases/y). We compared preoperative high-risk features between the center volume categories and assessed survival outcomes, focusing on 30-day and 1-year mortality. We further compared short-term perioperative morbidity outcomes.

Results

We analyzed 3397 patients from 69 institutions participating in the National Pediatric Cardiology–Quality Improvement Collaborative. Twenty-nine centers were classified as a low-, 20 as medium-, and 20 as high-volume centers. There was no difference in frequency of preoperative high-risk features among the center categories in the majority of considered variables. There was no association between the volume categories and 30-day mortality. Low-volume and medium-volume were associated with higher risk of 1-year mortality. This difference remained when adjusting for the presence of high-risk features (Low: odds ratio, 1.40 [95% CI, 1.03-1.60], P = .020; Medium: odds ratio, 1.28 [95% CI, 1.05-1.86], P = .025). Postoperative comorbidities were more frequent in low- and medium-volume centers, including the need for diagnostic and interventional catheterization.

Conclusions

Patients undergoing Norwood procedure in low- and medium-volume centers have worse 1-year mortality. The outcome characteristics are potentiated when adjusted for high-risk features, with significantly higher survival and lower morbidity in patients treated in high-volume centers.