Prognostic Value of Angiography-Derived Index of Microcirculatory Resistance in Patients with Coronary Artery Disease Undergoing Rotational Atherectomy

Background: Rotational atherectomy (RA) is the major tool used to treat severely calcified lesions in patients with coronary artery disease (CAD). The relationship between coronary microvascular dysfunction and RA remains unknown. Therefore, we attempted to ex-plore the predictive implications of the coronary angiography-derived index of microcirculatory resistance (angio-IMR) in CAD patients undergoing RA. Methods: This retrospective study included 118 patients with severe coronary calcification who underwent a successful RA from January 2018 to June 2021. The angio-IMR was calculated based on computed flow and pressure dynamic principles to assess coronary microcirculatory function. Follow-up was performed on all patients for major adverse cardiovascular events (MACEs), includ-ing all-cause death, non-fatal myocardial infarction, target vessel revascularization (TVR), and stroke. Results: The mean angio-IMR for all patients was 25.58 & PLUSMN; 7.93. Patients were stratified the groups based on a mean angio-IMR of 25, fifty-four (45.8%) patients had angio-IMR >25. The logistic regression analysis showed that angiography-derived fractional flow reserve was significantly associated with coronary microvascular dysfunction. After median follow-up of 21.7 (15.1-24.0) months, MACEs occurred in 30.6%, including 12.5% all-cause deaths, 6.4% non-fatal myocardial infarction, 14.5% TVR, and 0.9% stroke. Kaplan-Meier analysis demonstrated that patients with angio-IMR >25 had greater cumulative MACEs (41.6%) and TVR (20.7%) than patients with preserved angio-IMR. COX regression analysis indicated that angio-IMR >25 and reduced left ventricular ejection fraction were independent predictors of MACEs. In addition, angio-IMR >25 and lowered minimum luminal area independently predicted TVR occurrence. Conclusions: In CAD pa-tients undergoing RA, angio-IMR >25 was an independent and significant predictor of MACEs and TVR. Clinical Trial Registration: NCT05435898.