Abstract
Assessing coronary microcirculation is crucial in the progression of hypertrophic cardiomyopathy (HCM), but it's often inadequate in clinical practice. This study investigates the role of coronary microcirculation, assessed via angiography-derived index of microvascular resistance (angio-IMR), in predicting clinical outcomes in HCM patients. We retrospectively measured angio-IMR in 422 HCM patients across two sites. The primary endpoint was major advance cardiovascular event (MACE), including cardiovascular death, heart failure readmission, life-threatening ventricular arrhythmias, septal reduction therapy or new-onset stroke. Over a mean follow-up of 43 ± 23 months, 63 patients (14.93%) experienced MACE. The mean angio-IMR value for the left anterior descending artery (LAD) was 22 ± 8. Using maximally selected log-rank statistic, 123 patients were stratified into the high LAD angio-IMR group, indicating microvascular dysfunction. Patients with LAD angio-IMR > 25 exhibited a higher incidence of MACE than those with LAD angio-IMR ≤ 25 (25.4% vs. 13.3%, p = 0.035). After adjusting for risk factors, elevated LAD angio-IMR remained an independent predictor of MACE (HR 1.779, 95% CI, 1.053-3.007, p = 0.031). Subgroup analysis showed consistent results. Our findings underscore that elevated LAD angio-IMR is a robust, independent indicator of adverse prognosis in HCM patients, highlighting the importance of evaluating LAD angio-IMR during coronary angiography for these patients.