Abstract 14978: Association Between Microvascular Dysfunction and Heart Failure Related Outcomes in Ischemia With Non-Obstructive Coronary Arteries Based on a Novel Angiography-Derived Index

Abstract

Introduction: Coronary angiography-derived index of microvascular resistance (caIMR) is a index that quantifies coronary microvascular dysfunction (CMD), which obviates the need of wire manipulation compared to index of microvascular resistance (IMR). In patients with ischemia with non-obstructive coronary arteries (INOCA), CMD plays a key role and is associated with development of heart failure (HF). The significance of global CMD, reflected by the average of caIMR values obtained in the three coronary arteries was however not fully known. The aim of this study was to evaluate the association between HF related outcomes (HFRO) and global CMD in INOCA patients based on caIMR. Methods: Patients with clinical myocardial ischemia and without ≥50% diameter stenosis in any coronary arteries on coronary angiography were included. For every patient, the global-caIMR value was calculated by averaging caIMR values measured in the three major coronary arteries, and it reflects the extent of global CMD. Based on IMR threshold, patients were stratified into high-global-caIMR group (global-caIMR≥25U) and low-global-caIMR group (global-caIMR<25U). The primary endpoint was HFRO, defined by a composite of HF related hospitalization and outpatient diuretic intensification. Results: Among 325 patients included (mean age 63.4±11.0; male 57.2%), 105 and 220 patients were stratified into the high- and low-global-caIMR groups respectively. The rate of HFRO at 3 years was higher in the high-global-caIMR group compared to low-global-caIMR group (19.0% vs. 8.2%; P=0.004). In multivariable analysis adjusted for age, gender, Charlson Comorbidity Index and baseline HF, global-caIMR≥25U was associated with a higher risk of HFRO at 3 years (subdistribution hazard ratio [sHR], 2.65; 95% confidence interval [CI], 1.39-5.06; P=0.003). With the same multivariable adjustment, every 1U increase in global-caIMR was associated with an increased risk of HFRO at 3 years (sHR, 1.07; 95% CI, 1.05-1.09; P<0.001). Similar trends were observed at 5 years of follow-up. Conclusions: Global CMD, reflected by increased global-caIMR, was associated with a higher risk of HFRO at 3 and 5 years in INOCA patients. This study provides clinical data that support real-world application of caIMR.