Xincheng Sheng, Yumeng Hu, Yizhi Zhang, Jiyuan Chen, Jianping Xiang, Song Ding, Jun Pu
BACKGROUND: AccuIMR is a novel angiography-based method for assessing microvascular dysfunction (MVD) by simulating the index of microcirculatory resistance (IMR). In a prior study, AccuIMR showed a strong correlation with wire-based IMR. OBJECTIVES: This study aimed to evaluate the clinical significance of the angiography-derived index of microcirculatory resistance (AccuIMR) in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: This was a retrospective analysis of a prospective multicenter registry of STEMI patients who underwent cardiac magnetic resonance (CMR). This investigation included 482 STEMI patients. AccuIMR was obtained using angiographic images after percutaneous coronary intervention. The patients were categorized into the MVD group (AccuIMR >40) and the non-MVD group (AccuIMR ≤40). CMR results at 5 ± 2 days after percutaneous coronary intervention served as the reference standard for assessing CMR-derived microvascular obstruction (CMR-MVO) and infarct size. RESULTS: Compared with the non-MVD group, the MVD group exhibited a larger CMR-MVO area, a larger infarct size area, and a lower left ventricular ejection fraction. Multivariate logistic regression analysis indicated that AccuIMR >40 was an independent predictive factor for CMR-MVO (OR: 4.730, 95% CI: 2.868-7.799, P < 0.001) and larger infarct size (OR: 2.101, 95% CI: 1.323-3.337, P = 0.002). DeLong's test, net reclassification index/integrated discrimination improvement, and likelihood ratio test demonstrated that incorporating AccuIMR into conventional predictive factors significantly improved the predictive accuracy for CMR-MVO and larger infarct size. CONCLUSIONS: AccuIMR is an efficient and dependable method for evaluating MVD in STEMI patients after percutaneous coronary intervention. When combined with conventional predictive factors, it provides supplementary information regarding cardiac function.