Prognostic Assessment of Coronary Artery Bypass Patients Based on Coronary CTA: Vessel Weight and Native Artery Lesions Aid in Predicting Cardiovascular Events

Purpose The Fitzgibbon classification and Coronary Artery Disease—Reporting and Data System (CAD-RADS) were the main assessment methods for graft patency in post-coronary artery bypass graft (CABG) patients. Yet they only included the stenosis degree and have limited predictive power for long-term outcomes. We thus developed a novel scoring system (graft score) for graft evaluation in post-CABG patients by integrating stenosis degree, vessel weight coefficient, and native artery lesions based on coronary computed tomography angiography (CCTA) for guiding and optimizing post-CABG treatment. Methods This retrospective study enrolled consecutive post-CABG patients indicated for 1-year follow-up CCTA examination. The primary outcome was major adverse cardiovascular event (MACE). Multivariable Cox regression analysis, Harrell’s C-statistics, and continuous net reclassification were used for statistical analyses. Results A total of 402 patients (median age: 64 years, interquartile range: 58–69; 81.19% males) were included. Inclusion of the graft score or CAD-RADS while constructing clinical prediction models brought a significant net reclassification improvement (NRI) in MACE (graft score: NRI = 0.558, 95% CI 0.533–0.584, p < 0.001; CAD-RADS: NRI = 0.065, 95% CI 0.038–0.093, p = 0.017) compared with the inclusion of Fitzgibbon classification. Inclusion of the graft score significantly improved reclassification of the model with the CAD-RADS (NRI = 0.449, 95% CI 0.428–0.471, p < 0.001). In contrast, the modified Fitzgibbon classification did not provide such predictive superiority (NRI = 0.014, 95% CI − 0.011 to 0.039, p = 0.567). Conclusions The novel graft score based on CCTA outperformed the other three assessment methods in predicting the occurrence of MACEs suggesting that stenosis degree, vessel weight, and native coronary artery lesions should be all integrated in graft evaluation in post-CABG patients.