Epicardial Spasms May Increase the Risk for Myocardial Infarction

Among patients with coronary artery spasms, those with epicardial spasms had an increased risk for repeat angiography and myocardial infarction, according to a long-term follow-up study published in the Journal of the American College of Cardiologists: Cardiac Interventions.

A total of 736 patients (mean age, 62±12 years; 57% women who were symptomatic despite unobstructed coronary arteries were prospectively enrolled between 2007 and 2010 in Germany, and followed for a median of 7.2 years (range, 6.5-7.9 years). Study participants underwent acetylcholine spasm testing (ACh-test) to determine the presence of epicardial or microvascular coronary spasms. Epicardial spasms were defined by angina and ischemic electrocardiogram (ECG) shifts with more than 75% focal or diffuse coronary artery diameter reduction. Microvascular spasms were defined as an angina and ischemic EGC shifts in the absence of epicardial spasms.

In this cohort, 55 patients (7.5%) died during the follow-up period (annual all-cause mortality rate, 1.1%). Deaths were from noncardiac causes (n=46), or due to myocardial infarction (MI; n=3), decompensated heart failure (n=2), and heart rhythm disorder (n=1).

Nonfatal MIs occurred in 1.4% of patients who were more likely than those without MI to have epicardial spasms (P =.012). De novo stenosis occurred in 75% of patients who experiences a nonfatal MI. No instance of MI was observed in patients with a normal (P =.096) or inconclusive (P =.075) Ach-test. Nonfatal strokes (2.2%) and recurrent symptoms (64%) were observed in this cohort.

Epicardial spasms were found to increase the risk for nonfatal MI (hazard ratio [HR], 14.369; 95% CI, 1.727-119.528) and repeated angiography (HR, 1.699; 95% CI, 1.061-2.719). Microvascular spasms increased the risk for recurrent angina (HR, 1.318; 95% CI, 1.004-1.730).

A limitation of this study was the small sample size. In addition, many of the originally recruited patients were lost before follow-up, and it remains unclear whether these patients were lost due to adverse events or death, so that reported rates may have been underestimated.

“These results demonstrate the prognostic value of ACh-testing regarding morbidity and underline the importance of performing coronary functional testing in this overall low-risk, but challenging patient population with angina but [unobstructed coronary arteries],” concluded the study authors.

Reference

Seitz A, Gardezy J, Pirozzolo G, et al. Long-term follow-up in patients with stable Angina and unobstructed coronary arteries undergoing intracoronary acetylcholine testing. JACC Cardiovasc Interv. 2020;S1936-8798(20)31139-0. doi:10.1016/j.jcin.2020.05.009