Understanding Mortality After Congenital Heart Surgery: What Do Procedure-Specific Factors Add?

BACKGROUND: Although collected by The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) since 2013, the value of procedure-specific factors (PSFs) in improving our understanding of expected mortality has not been studied. We evaluated the contribution of PSFs across a large cohort.

METHODS: Included were benchmark operations (BMO) for which PSFs are captured across 115 United States centers (2016-2022). We assessed the influence of PSFs on operative mortality discrimination and determined which specific PSFs had the most impact. Advanced modeling strategies were used given the numerous covariates and relatively low mortality rates. A baseline model (including standard STS-CHSD clinical risk variables) was compared with a baseline plus PSF model, with results reported overall and stratified by BMO.

RESULTS: Among 37,282 included BMOs, overall operative mortality was 2.6%. The proportion of BMOs with at least 1 PSF recorded as present ranged from 2.7% for ventricular septal defect to 85% for Norwood. Model discrimination increased from 0.088 (baseline) to 0.095 (baseline + PSF) overall, with better discrimination for 5 of 9 BMOs. Results for individual PSFs varied by BMO and analytic method. No PSFs were retained in the final models for ventricular septal defect in any scenario. The greatest number of PSFs were retained for Norwood and truncus arterious repair.

CONCLUSIONS: Incorporating PSFs into expected mortality models improved model discrimination for some BMOs, and certain PSFs had an important impact on mortality estimates, whereas others did not. These data can aid in reducing data collection burden and support ongoing refinement of risk models.