Coronary Index of Microcirculatory Resistance in Stable Angina with or without Significantly Obstructive Coronary Atherosclerosis

초록

Background Microvascular angina (MVA) was defined as patients with ischemic chest pain and evidence of myocardial ischemia on the noninvasive test, but without obstructive coronary atherosclerosis. Patients with microvascular angina had increased coronary microvascular resistance. In addition, mean coronary index of microcirculatory resistance (IMR) was higher in patients with epicardial coronary lesion compared without epicardial lesion. We investigated by comparing IMR according to presence or absence of significantly obstructive coronary atherosclerosis (CAOD) in patients with evidence of myocardial ischemia on the treadmill exercise test. Methods We recruited patients with typical effort angina symptom and positive treadmill exercise test result. Patients were divided into two groups based on angiographic stenoses. The MVA group was presented with completely normal coronary artery, and the CAOD group had only single significant epicardial lesion (more than 50% diameter stenosis) in the left anterior descending artery. Treadmill exercise test was performed for assessing myocardial ischemia severity by Duke treadmill score (DTS). Results Total 30 patients were enrolled in the present study. 14 patients were the MVA group, while 16 patients were the CAOD group. Fractional flow reserve (FFR) and diameter stenosis revealed significant difference between groups. CFR was relatively lower in the CAOD group compared with the MVA group (2.16 ± 1.14 vs. 3.31 ± 2.02, p=0.061). However, IMR value were similarly distributed between groups (21.92 ± 9.82 vs. 20.38 ± 8.64, p=0.654). DTS showed no significant difference among both groups (-4.60 ± 5.20 vs. -4.45 ± 4.84, p=0.952) Conclusions Mean IMR was similarly presented between patients with or without epicardial obstructive coronary atherosclerosis who had evidence of myocardial ischemia on the treadmill exercise test.