Abstract 5517: Coronary Microvessel Spasm is a Frequent Cause of Myocardial Ischemia in Women With Angina-like Chest Pain

Abstract

Background: Angina without coronary stenosis is frequent in women, indicating that non-obstructive coronary artery disease (NOCAD) including coronary spasm should be clinically examined. Coronary microvessel spasm (CMVS) as well as epicardial coronary artery spastic angina (eCSA) can cause NOCAD, however clinical significance and diagnostic criteria of CMVS have not been established. Methods and Results: 239 consecutive patients suspected NOCAD (135 women and 104 men, age 64±11) were investigated by the intra-coronary acetylcholine-provocation test (ACh-test) with simultaneous measurement of cardiac lactic acid production (CLAP) and coronary blood flow volume (CBFV) calculated from average peak velocity using Doppler FloWire and coronary diameter by quantitative coronary angiography. eCSA was predominantly provoked in men [women 66 (48.9%) vs. men 75 (72.2%), p<0.001]. We diagnosed CMVS by our following criteria; occurrence of chest pain with ischemic electrocardiographic change, decrease in CBFV, and positive CLAP without epicardial spasm. CMVS was significantly frequent in women [women 30 (22.2%) vs. men 2 (1.9%), p<0.001]. 51 patients (21.3%) exhibited no evidence of myocardial ischemia by ACh-test [control; women 26 (19.3%) vs. men 25 (24.0%), p=0.37] and remaining 15 patients (6.3%) showed equivocal results. At baseline condition, CMVS patients showed significantly lower coronary flow values of diastolic to systolic velocity ratio compared to control (1.5±0.2 vs. 1.9±0.4, p<0.001). Women with CMVS exhibited significant decrease in CBFV (−50.7±24.0%, p<0.001) and increase in CLAP (31.8±30.7%, p<0.001) as compatible as eCSA by ACh-test (eCSA: CBFV; −45.2±40.7%, p=0.58, CLAP; 29.1±44.7%, p=0.74). We treated both patients with CMVS and eCSA by calcium-channel blockers. During 39 months follow-up, four cardiovascular events were documented in patients with eCSA, however, none in patients with CMVS. Conclusion: CMVS is the frequent cause of myocardial ischemia (22%) in women with chest pain and the medical treatment with calcium-channel blockers is effective. CMVS could be clinically identified as NOCAD by the diagnostic ACh-test with simultaneous measurement of CLAP and CBFV to provide optimal care for improving prognosis.