Having cleaner-looking arteries on a scan is not giving women the break many might expect. In a new analysis of CT coronary images from more than 4,200 people with stable chest pain, women ran into death, heart attacks or hospitalizations at lower plaque levels than men, even though they had less overall plaque. The results call into question one-size-fits-all plaque cutoffs and suggest cardiologists may need a different playbook when they read coronary CT scans for women.
Study details
The study, published February 23 in Circulation: Cardiovascular Imaging, drew on imaging and outcome data from 4,267 adults enrolled in the PROMISE trial who were followed for a median of 26 months. Participants, whose average age hovered around 60 and of whom 51% were women, had coronary CT angiography at 193 clinical sites across the United States and Canada. Researchers measured total plaque volume and overall plaque burden, then tracked major adverse cardiovascular events such as death, myocardial infarction and hospitalization for unstable angina, according to the Circulation: Cardiovascular Imaging paper.
Surprising numbers
Fewer women had any detectable coronary plaque at all, 55% of women compared with 75% of men, and the median plaque volume for women was about 78 mm³ versus 156 mm³ for men. Yet during follow-up, short-term event rates were in the same ballpark, 2.3% for women and 3.4% for men, as reported by Cleveland.com. Put bluntly, having less plaque on the scan did not translate into clearly lower near-term risk for the women in this group.
Why less plaque isn't protective
Senior author Borek Foldyna said the findings show women are not “protected” from coronary events just because their plaque volumes tend to be lower. He noted that “a small amount of plaque can have a bigger impact in women because they have smaller coronary arteries,” according to a news release from the American Heart Association. The paper and related coverage point to plaque makeup, artery size and how risk climbs with added plaque as possible reasons for the sex-based differences.
Where risk starts to climb
When the team plotted risk against plaque burden, the total plaque-burden level where the hazard ratio crossed 1.0 showed up at roughly 20% plaque burden in women compared with 28% in men. From there, the risk curve rose more sharply for women, hitting a hazard ratio of 1.5 at about 32% plaque burden versus 42% in men, according to the Circulation: Cardiovascular Imaging report. Noncalcified plaque burden followed a similar sex-specific pattern, and the results held up even after adjustment for standard atherosclerotic risk scores.
Takeaways for patients and doctors
Lead author Jan Brendel said the data “suggest that applying uniform thresholds across sexes to determine whether patients' plaque measures put them at high risk for MACE may underestimate risk in women,” according to a Mass General Brigham news release. Clinicians stress that this work is about sharpening risk assessment in patients who already have symptoms, not about backing coronary CT scans for people who feel fine.
Bottom line
The study adds to evidence that women’s heart-disease risk can look different on imaging and underscores the need for sex-specific plaque interpretation. Women who have chest pain or several risk factors are urged to go over their scan results and treatment options carefully with a clinician, and researchers say further trials will need to test whether acting at these lower plaque thresholds actually improves outcomes.
