Women who have two or more risk factors -- such as obesity, smoking or metabolic syndrome -- along with a family history of heart disease should be considered for a fast cardiac CT scan regardless of low risk-factor scores, say researchers.

The latest findings are published in the American Heart Journal.

"Our best means of preventing coronary heart disease is to identify those most likely to develop the condition and intervene with lifestyle changes and drug treatment before symptoms start to appear," says cardiologist Roger Blumenthal, MD, senior author of both studies. Dr. Blumenthal is an associate professor and director of the Ciccarone Preventive Cardiology Center at the Johns Hopkins University School of Medicine and its Heart Institute.

"The goal is to strongly consider therapies, such as aspirin, cholesterol-lowering medications and, possibly, blood pressure medications for individuals at higher risk," he notes, "so that heart attacks will be less likely to occur in the future."

Problems Go Undetected

While the death rate for men from cardiovascular disease has steadily declined over the last 20 years, the rate has remained relatively the same for women. The Johns Hopkins researchers wanted to determine why many women at risk for heart disease are not identified earlier.

Their findings are believed to represent the first critical assessments of the Framingham Risk Estimate (FRE) as the principal test for early detection of heart disease.

The FRE, which is designed to determine how likely a person is to suffer a fatal or nonfatal heart attack within 10 years, is based on a summary estimate of major risk factors for coronary heart disease: age, blood pressure, blood cholesterol levels and smoking.

However, many women with cardiovascular problems go undetected despite use of the Framingham score, Dr. Blumenthal points out.

Framingham Score Underestimates Risk

In the latest study, the Hopkins team examined the risk of premature CHD in women whose average age was 50 and who were participating in the Sibling and Family Heart Study, a long-term analysis of how heart disease develops among family members. Research subjects had no symptoms of heart disease, but each had a sibling who had been hospitalized for a coronary event, such as a heart attack, before age 60.

After calculating each woman’s Framingham score, the Hopkins team found that 98 percent were gauged to be at very low risk for future CHD, with an FRE of less than 6 percent, while only 2 percent of participants were judged to be at intermediate risk for future CHD, with an FRE of 10-20 percent.

When the results were contrasted with evidence gleaned from CT-scan measurements of calcium buildup in the arteries, the researchers found that one-third of the women originally classified as very low risk actually had coronary atherosclerosis -- hardening and narrowing of the arteries that can lead to heart attacks if not controlled with drug therapy along with diet, exercise and other lifestyle changes.

Twelve percent of the participants had advanced stages of atherosclerosis, while another 6 percent had severe calcium buildup.

"We wanted to verify if the Framingham score truly captured who was most at risk, but it turns out to have underestimated a large number of those who should be considered for preventive therapies," says Dr. Blumenthal.

Two or More Factors

Performing cardiac CT scans on everyone with a low Framingham score is not a practical option for improving upon traditional risk-factor screening, the researchers maintain.

The investigators searched for additional predictors of those most vulnerable in order to determine who should get scanned, despite a low risk assessment.

Those who had two or more risk factors (e.g., obesity, smoking or metabolic syndrome) along with a family history of heart disease were most likely to have a high calcium score, they found. It is this group, the researchers say, who should be considered for a fast cardiac CT scan regardless of low Framingham scores.

In a related investigation published earlier this year in the journal Atherosclerosis, the same Hopkins team analyzed the Framingham scores of 2,447 women age 45-65, all of whom were participating in another long-term study in Ohio of adults referred by a physician for a cardiac risk assessment.

When the FRE results were compared to calcium scores, 84 percent (408 of 489) of those classified as low risk by FRE actually had some coronary atherosclerosis. Twenty percent of those who were classified at intermediate risk by FRE had signs of advanced atherosclerosis.

"Our results show that if a CT scan had not been performed in addition to traditional risk-factor scoring, a large number of women would have missed the chance to begin preventive therapies," says cardiologist Erin Michos, MD, a clinical research fellow at Hopkins and its Heart Institute. Michos led both Hopkins studies.

"For some women, especially those with a family history of heart disease and multiple risk factors for it, additional screening using CT scan and calcium scoring may be warranted," she adds.