National Variation in Congenital Heart Surgery Outcomes.

Background: Optimal strategies to improve national congenital heart surgery outcomes and reduce variability across hospitals remain unclear. Many policy and quality improvement efforts have focused primarily on higher-risk patients and mortality alone. Improving our understanding of both morbidity and mortality and current variation across the spectrum of complexity would better inform future efforts.
Methods: Hospitals participating in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2014-2017) were included. Case mix-adjusted operative mortality, major complications, and postoperative length of stay were evaluated using Bayesian models. Hospital variation was quantified by the interdecile ratio (IDR, upper versus lower 10%) and 95% credible intervals (CrIs). Stratified analyses were performed by risk group (Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery [STAT] category) and simulations evaluated the potential impact of reductions in variation.
Results: A total of 102 hospitals (n=84 407) were included, representing ≈85% of US congenital heart programs. STAT category 1 to 3 (lower risk) operations comprised 74% of cases. All outcomes varied significantly across hospitals: adjusted mortality by 3-fold (upper versus lower decile 5.0% versus 1.6%, IDR 3.1 [95% CrI 2.5-3.7]), mean length of stay by 1.8-fold (19.2 versus 10.5 days, IDR 1.8 [95% CrI 1.8-1.9]), and major complications by >3-fold (23.5% versus 7.0%, IDR 3.4 [95% CrI 3.0-3.8]). The degree of variation was similar or greater for low- versus high-risk cases across outcomes, eg, ≈3-fold mortality variation across hospitals for STAT 1 to 3 (IDR 3.0 [95% CrI 2.1-4.2]) and STAT 4 or 5 (IDR 3.1 [95% CrI 2.4-3.9]) cases. High-volume hospitals had less variability across outcomes and risk categories. Simulations suggested potential reductions in deaths (n=282), major complications (n=1539), and length of stay (101 183 days) over the 4-year study period if all hospitals were to perform at the current median or better, with 37% to 60% of the improvement related to the STAT 1 to 3 (lower risk) group across outcomes.
Conclusions: We demonstrate significant hospital variation in morbidity and mortality after congenital heart surgery. Contrary to traditional thinking, a substantial portion of potential improvements that could be realized on a national scale were related to variability among lower-risk cases. These findings suggest modifications to our current approaches to optimize care and outcomes in this population are needed.