Development and Validation of Risk Models for Outcomes of Isolated Coronary Artery Bypass Grafting　- A Nationwide Analysis in Japan.

Background

Reliable preoperative risk assessment is essential in cardiac surgery. In Japan, coronary artery bypass grafting (CABG) risk models have been developed from the Japan Cardiovascular Surgery Database - Adult section (JCVSD-A), with JapanSCORE I and II released previously. To reflect contemporary practice, we developed and validated JapanSCORE III, an updated risk model for isolated CABG, using JCVSD-A.

Methods

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Results

We identified patients undergoing isolated CABG between 2018 and 2023 in the JCVSD-A. The dataset was temporally split into development (2018-2022) and validation (2023) cohorts. A least absolute shrinkage and selection operator model was developed to predict operative mortality, incorporating imaging-based predictors and clinically relevant factors. Secondary outcome models were constructed for stroke, reoperation, prolonged ventilation, renal failure, deep sternal wound infection (DSWI), gastrointestinal complications, and intensive care unit stay >7 days. Model performance was assessed by areas under the curve (AUC) and calibration plots. Among 70,180 patients (mean age 69.3 years; 20% women), operative mortality was 2.7%. The incidence of stroke, reoperation, prolonged ventilation, renal failure, DSWI, gastrointestinal complications, and prolonged ICU stay was 1.8%, 1.5%, 3.7%, 2.0%, 1.1%, 1.3%, and 13.2%, respectively. Operative mortality and renal failure models demonstrated good discrimination (AUC >0.8) and calibration in validation.

Conclusions

Operative outcomes remained stable despite increasing predicted risk. The JapanSCORE III models showed good predictive performance, providing valid tools for preoperative risk stratification.