Coronary Micro-vessel Spasm and Angina-like Chest Pain

A study by Keisuke Ohba and colleagues from the Department of Cardiovascular Medicine, Graduate School of Medical Sciences at Kumamoto University, presented results from their study "Coronary Micro-vessel Spasm is a Frequent Cause of Myocardial Ischemia in Women with Angina-like Chest Pain" during an abstract poster session Tuesday at the American Heart Association Scientific Sessions 2009. The study looked at the relationship between coronary micro-vessel spasm, epicardial coronary artery spastic angina, and non-obstructive coronary artery disease.

Researchers identified 239 consecutive patients with suspected non-obstructive coronary artery disease (135 women and 104 men, with an average age of 64 years), and administered an intra-coronary acetylcholine-provocation test (ACh-test) to each patient. Cardiac lactic acid production (CLAP) was also simultaneously measured in each patient, along with "coronary blood flow volume (CBFV) calculated from average peak velocity using Doppler FloWire" and "coronary diameter by quantitative coronary angiography." Epicardial coronary artery spastic angina was provoked in 72% of men and in 49% of women.

The researchers used the following criteria to diagnose CMVS in this cohort: occurrence of chest pain with ischemic electrocardiographic change, decrease in CBFV, and positive CLAP without epicardial spasm. Coronary micro-vessel spasm was present in 22% of women and in 2% of men.

ACh-testing revealed that 21% of patients showed no evidence of myocardial ischemia. Patients with baseline CMVS showed "significantly lower coronary flow values of diastolic to systolic velocity ratio compared to controls." Women with CMVS experienced a significant decrease in CBFV and increase in CLAP.

During 39 months follow-up, researchers documented four cardiovascular events in patients with eCSA; no cardiovascular events were documented in patients with CMVS. The authors conclude that "CMVS is the frequent cause of myocardial ischemia (22%) in women with chest pain," and that "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" in this patient population.