Cocaine users in their mid-40s have more than four times the risk of coronary artery aneurysms as non-users of the same age, according to an article in the May 17th issue of Circulation. Although the current study is the first to document an association between cocaine use and coronary aneurysms, the findings may help explain the known higher risk for myocardial infarction in this population.

“We found a significantly higher percentage of aneurysms in patients who had used cocaine than in a group of patients of similar age who did not,” said the study’s senior author, Timothy D. Henry, MD.

Researchers examined the records of 191 men and women, including 112 cocaine users who underwent angiography for known or suspected heart problems during a 10-year period and 79 age-matched controls who also underwent angiography. Henry and his American colleagues identified definite or probable aneurysms in the coronary arteries of 30.4 percent of the cocaine users compared with only 7.6 percent of non-user controls.

The average age of cocaine users was 43.7 years and that of non-users was 45.6 years, an insignificant difference. Males made up 80 percent of the cocaine group compared with 61 percent of the nonuser group, a statistically significant difference. About 95 percent of the cocaine users smoked compared with 71 percent of the control group.

The same three cardiologists read the angiogram of each patient to assess the presence or absence of coronary artery aneurysms. They classified patients as having a definite coronary artery aneurysm if all three readers agreed an aneurysm was present. An aneurysm was deemed “probable” if two readers agreed. In the cocaine group, 24 patients had definite coronary artery aneurysms and 10 had probable coronary artery aneurysms.

Among all study participants, a previous myocardial infarction and cocaine use were the strongest predictors that a patient would have an aneurysm. Previous infarction was common in both groups ? 45 percent of cocaine users and 38 percent of control patients.

“The extremely high prevalence of coronary artery aneurysms in cocaine users is striking compared with the control group,” Henry said. It is also much higher than the rate of coronary artery aneurysms found in previous studies of patients undergoing angiography, which ranged from 0.2 to 5.3 percent.

About 50 percent of coronary artery aneurysms are related to the presence of atherosclerosis. Those aneurysms rarely burst, and thus do not carry the same direct risk of death from a rupture as aneurysms in the brain and those in the aorta. But at least in cocaine users, coronary artery aneurysms may contribute to death in another way ? by increasing risk for myocardial infarction.

The authors suggest two possible ways that cocaine might weaken the artery wall and lead to an aneurysm: The drug can cause sharp spikes in blood pressure and it can damage endothelial cells. It is possible that altered blood flow through an aneurysm facilitates thrombosis, which can trigger ischemia or frank infarction.