Heart disease without coronary plaque buildup linked to heart attack risk

Non-obstructive coronary artery disease was associated with a 28 to 44 percent increased risk of a major adverse cardiac event such as a heart attack or death, in a new study presented at the American Heart Association's Quality of Care and Outcomes Research 2014 Scientific Sessions.

Non-obstructive CAD damages the walls of the heart's blood vessels, but doesn't result in decreased blood flow or symptoms so it's generally been considered to be a low-risk condition.

In this study, researchers studied 40,872 veterans who underwent elective cardiac angiography from October 2007 to September 2012. The patients' condition was categorized as normal, non-obstructive and obstructive CAD. The rates of heart attack and death within one year following angiography increased progressively with increasing CAD severity, even among those patients with non-obstructive CAD, researchers found.

"Unlike obstructive CAD, which blocks blood flow, non-obstructive CAD may initially appear less threatening on angiography tests since it doesn't result in decreased blood flow, but it appears to have significant risk for heart attack and death" said Thomas M. Maddox, M.D., M.Sc., the study's lead researcher, a cardiologist for the VA Eastern Colorado Health Care System and associate professor of medicine at the University of Colorado School of Medicine in Denver. "Dismissing non-obstructive CAD as harmless could be dangerous. Our findings show there is indeed a risk, that non-obstructive damage can lead to heart attacks just like obstructive disease, and that we should consider preventive therapies for these patients."

Patients with non-obstructive disease should ask their physicians about preventative therapies, like quitting smoking, healthy diets, getting enough exercise, losing weight and taking preventative medications such as aspirin and statins.