(RxWiki News) Coronary artery disease can be split into two separate categories: obstructive and non-obstructive, or high-risk and low-risk. New research suggests that this black and white view of the condition may be deadly.
A recent study found that patients with non-obstructive coronary artery disease still had a higher risk for death or heart attack than people who did not have coronary artery disease.
The researchers discovered that patients with non-obstructive coronary artery disease in three blood vessels were more likely to have a heart attack or die than patients with obstructive coronary artery disease in one vessel.
These researchers argued that doctors need to pay more attention to the risks associated with non-obstructive coronary heart disease, as it is usually considered a low-risk condition.
"Discuss screening for coronary artery disease with your cardiologist."
The lead author of this study was Thomas M. Maddox, MD, MSc, from the Department of Cardiology of the VA Eastern Colorado Health Care System in Denver, Colorado and the University of Colorado School of Medicine in Aurora, Colorado.
The study included 40,872 veterans who underwent elective angiography between October 2007 and September 2012.
Angiography is a test that uses dyes and special types of x-rays to look at a person’s coronary arteries. The coronary arteries supply oxygen-rich blood to the heart.
The researchers categorized the participants by extent of coronary artery disease, and assessed whether any of the participants had a heart attack or died within one year of angiography.
Coronary artery disease (CAD) is a condition in which a waxy substance called plaque builds up inside the coronary arteries, causing the area through which blood flows to narrow. This narrowing is called stenosis.
The findings of this study showed that 8,411 (21 percent) of the participants did not have CAD.
A total of 5,219 (18 percent) of the participants had non-obstructive CAD in one vessel, 3,034 (10 percent) had non-obstructive CAD in two vessels, and 1,388 (5 percent) had non-obstructive CAD in three vessels.
Non-obstructive CAD means that at least 70 percent of the vessel has no stenosis. The condition damages the walls of the vessels, but doesn’t decrease blood flow or show typical symptoms of CAD, so it’s generally been considered to be a low-risk condition.
The researchers found that 8,588 (29 percent) of the participants had obstructive CAD in one vessel, 5,227 (18 percent) had obstructive CAD in two vessels, and 6,017 (20 percent) had obstructive CAD in three vessels.
Obstructive CAD means that a vessel has more than 70 percent stenosis.
Dr. Maddox and team found that compared to the participants with CAD, those with non-obstructive CAD in one vessel were 28 percent more likely to die or have a heart attack.
The participants with non-obstructive CAD in two vessels were 29 percent more likely, and the participants with non-obstructive CAD in three vessels were 44 percent more likely, to die or have a heart attack compared to the participants with no CAD.
The findings revealed that the participants with obstructive CAD in one vessel were 93 percent more likely than the participants with no CAD to have a heart attack or die.
Those who had obstructive CAD in two vessels and three vessels were 2.73 times and 2.98 times more likely to have a heart attack or die compared to those with no CAD.
The researchers highlighted the finding that the participants with non-obstructive CAD in three vessels were 34 percent more likely to die or have a heart attack compared to the participants with obstructive CAD in one vessel. One potential reason for this outcome is that the plaque in non-obstructive cases of CAD can still rupture and cause heart attacks.
“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,” Dr. Maddox said in a press statement. “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.”
He suggested that patients with non-obstructive CAD talk to their doctors about preventive strategies, such as quitting smoking, getting enough exercise, losing weight, eating a healthy diet and taking preventive medications like aspirin or statins.
This study was presented on June 4 at Quality of Care and Outcomes Research 2014.
The Department of Veterans Affairs provided funding.