Non-Obstructive Coronary Artery Disease Still Confers Heart Attack Risk

Thomas M. Maddox MD MSc Cardiology, VA Eastern Colorado Health Care System Associate Director, VA CART Program MedicalResearch.com Interview with:
Thomas M. Maddox MD MSc
Cardiology, VA Eastern Colorado Health Care System
Associate Director, VA CART Program
Associate Professor, Department of Medicine
University of Colorado School of Medicine

Medical Research: What is the background for this study? What are the main findings?

Dr. Maddox: Nonobstructive coronary artery disease (CAD) is atherosclerotic plaque that would not be expected to obstruct blood flow or result in anginal symptoms (such as chest pain). Although such lesions are relatively common, occurring in 10 percent to 25 percent of patients undergoing coronary angiography, their presence has been characterized as “insignificant” or “no significant CAD” in the medical literature. However, this perception of nonobstructive coronary artery disease may be incorrect, because prior studies have noted that the majority of plaque ruptures and resultant myocardial infarctions (MIs; heart attacks) arise from nonobstructive plaques. Despite the prevalence of nonobstructive CAD identified by coronary angiography, little is known about its risk of adverse outcomes, according to background information in the article.

During the study period, 37,674 patients underwent elective coronary angiography for indications related to CAD; of those, 22.3 percent had nonobstructive CAD and 55.4 percent had obstructive CAD. Within 1 year, 845 patients died and 385 were rehospitalized for myocardial infarction. The researchers found that the 1-year myocardial infarction risk progressively increased by the extent of coronary artery disease, rather than abruptly increasing between nonobstructive and obstructive CAD. Patients with nonobstructive CAD had an associated risk of MI that was 2-to 4.5-fold greater than among those with no apparent coronary artery disease. Similar observations were seen with 1-year mortality and the combined outcome of 1-year myocardial infarction and death.

Medical Research: What should clinicians and patients take away from your report?

Dr. Maddox: The take home message for clinicians is recognizing that non-obstructive coronary artery disease isn’t insignificant or benign, but instead confers significant risk for myocardial infarction and mortality.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Maddox: Consideration of preventative therapies – such as aspirin, statins, and lifestyle modifications such as smoking cessation, weight loss, and increased physical activity – should be considered in all patients with non-obstructive coronary artery disease. Trials testing the effectiveness of these therapies in patients with non-obstructive CAD should also occur.

Citation:

Maddox TM, Stanislawski MA, Grunwald GK, et al. Nonobstructive Coronary Artery Disease and Risk of Myocardial Infarction. JAMA. 2014;312(17):1754-1763. doi:10.1001/jama.2014.14681.