WEDNESDAY, Nov. 30 (HealthDay News) -- Not all clogged arteries are created equal, with women and men facing different heart risks even when they have the same amount of coronary plaque, a new study suggests.

Analyzing the results of coronary CT angiographies -- non-invasive tests that look for coronary artery blockages -- in 480 patients with acute chest pain, scientists from the Medical University of South Carolina found that the risk of major cardiac events was significantly higher in women when they had a large amount of plaque buildup and extensive hardening of the arteries.

On the other hand, men faced greater risks of heart attack or coronary bypass surgery when their arteries contained "non-calcified plaque," fatty deposits that accumulate deep in artery walls.

While the study didn't specifically quantify the risks of each scenario for men and women, it may be valuable to physicians ordering tests for heart patients in distress, said study author Dr. John Nance Jr., a radiology resident at Johns Hopkins Hospital in Baltimore.

"This is so intriguing because now we're really starting to figure out the gender differences in heart disease," said Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City. She was not involved in the study.

"We've known in the past that women tend to deposit plaque differently . . . this nuance is something that's relatively new in how we risk-stratify patients," she added. "What it tells us is when we risk-stratify patients, it becomes more important to actually visualize plaque through CTA [angiography] or catheterization."

The study was slated to be presented Wednesday at a meeting of the Radiological Society of North America, in Chicago. Research presented at scientific meetings is preliminary and has not yet been peer-reviewed.

Study participants, two-thirds of whom were women, were an average age of 55. Using the coronary CT angiographies, researchers were able to determine the number of blood vessel segments with plaque, the severity of the blockage and the composition of the plaque.

By comparing those results with data accumulated over a nearly 13-month follow-up period, the researchers were able to link these factors with the incidence of major cardiac events. The analysis tested all types of coronary plaques -- non-calcified, calcified and mixed -- along with each individual type separately.

In the follow-up period, 70 patients suffered major cardiac events, including death, heart attack, unstable angina or bypass surgery.

"We're not sure why the risk differences exist [between the sexes] but women have smaller blood vessels and men have larger," said Dr. Jennifer Mieres, a cardiologist with the North Shore-LIJ Health System in Manhasset, N.Y. "We also believe that atherosclerosis (artery hardening) differs in how it's deposited in men and women."

Using this information will help doctors tailor treatments to each gender and customize their care, the health experts agreed.

"I think this is the sort of stuff we're going to start seeing more and more of," Nance said. "There are people out there who are anti-customized care and just don't think that's what we should really strive for, but this data kind of argues for that."

More information

The U.S. National Library of Medicine has more about atherosclerosis.