Non-Obstructive CAD Raises Myocardial Infarction Risk

A retrospective study finds that non-obstructive coronary artery disease (CAD) is associated with an elevated risk for myocardial infarction (MI) and death.

In an effort to compare myocardial infarction and mortality rates between patients with non-obstructive CAD, obstructive CAD, and no apparent CAD in a national cohort, a team including investigators from the VA Eastern Colorado Health System, the University of Colorado School of Medicine, and Duke University analyzed data from 37,674 elective angiography patients in the Veteran Affairs system.
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The researchers found that 20,899, or 55%, of these patients had obstructive CAD, while 8,384 (22%) were found to have non-obstructive coronary artery disease. At 1 year, the risk for MI and death was greater, based on the severity and extent of the CAD.

In comparison to those with no CAD, myocardial infarction risk was 2 to 4.5 times greater in patients with non-obstructive coronary artery disease. According to the authors, the risk rose with obstructive disease, meaning that individuals with obstructive 3-vessel or left main disease were at nearly 20 times the risk for myocardial infarction.

These findings "suggest clinical importance of non-obstructive CAD, and warrant further investigation of interventions to improve outcomes among these patients,” the authors wrote.

From a clinician standpoint, it’s important to recognize that “non-obstructive CAD isn’t significant or benign, but instead confers significant risk for myocardial infarction and mortality,” says Thomas Maddox, MD, MSc, a cardiologist in the department of veteran affairs at VA Eastern Colorado Health Care System, and lead author of the study.

“Preventive therapies such as aspirins, statins, and lifestyle modifications such as smoking cessation, weight loss, and increased physical activity should be considered in all patients with non-obstructive CAD,” adds Maddox, noting that “trials testing the effectiveness of these therapies in patients with non-obstructive CAD should also occur.”

—Mark McGraw

Reference

Maddox T, Stanislawski M, et al. Nonobstructive Coronary Artery Disease and Risk of Myocardial Infarction. JAMA. 2014.