Yoshimitsu Honda

Background: After coronary artery bypass grafting (CABG), graft and native-vessel anatomy complicate perfusion SPECT, and preoperative thresholds transfer poorly. We evaluated whether perfusion-anatomy concordance on hybrid SPECT/CT was associated with major adverse cardiac events (MACE) and compared it with perfusion severity and 123I-BMIPP mismatch.Methods: This retrospective study included 131 consecutive post-CABG patients who underwent stress/rest perfusion SPECT, 123I-BMIPP SPECT, and coronary CT angiography. Hybrid status was matched when a reversible defect corresponded to significant stenosis or occlusion in the supplying native artery or graft. Firth-penalized Cox regression was prespecified (5.4 events per parameter).Results: Over a median follow-up of 99.7 months (interquartile range 47.9–115.7), MACE occurred in 27 patients (20.6%). Event proportions were 38.8% versus 9.8% by matched status (log-rank P < 0.001), 30.4% versus 13.3% for a summed difference score ≥ 4 (P = 0.009), and 22.8% versus 18.9% for a summed mismatch score ≥ 7 (P = 0.269). After clinical adjustment, matched status remained associated with MACE (Firth-penalized hazard ratio 3.9970; 95% confidence interval 1.7666–9.7395; P < 0.001). This model showed the lowest unpenalized Akaike information criterion (226.32) and the highest ridge-stabilized optimism-corrected concordance index (0.704), with no proportional-hazards violation detected (P = 0.731). Perfusion severity was associated with MACE (unpenalized hazard ratio 2.9219; 1.2039–7.0916; P = 0.018) but showed evidence of nonproportional hazards (P = 0.036).Conclusions: Perfusion-anatomy concordance identifies a high-risk post-CABG subgroup. It provided the best model fit and, unlike perfusion severity, no evidence of nonproportional hazards. BMIPP mismatch was not associated with MACE.