DURHAM, N.C. — When some people have heart attacks, there are warning signs. Unfortunately, that is not the case for everyone.

A new program at Duke Medical Center is aimed at identifying those most at-risk for heart disease.

At his last visit to Duke, John Squire had more than just his weight and blood pressure checked. He received a CT heart scan to evaluate his heart disease risk.

"I just figured, you know, it's like an insurance policy -- get it done once and then you know you don't have to worry about it," he said.

The heart scan is part of a new comprehensive program at the Duke Heart Center.

Doctors first evaluate the standard risk factors for heart disease -- age, sex, smoking history, blood pressure, cholesterol and blood sugar. Those factors only predict about half of heart disease cases.

"The standard risk factors don't define all of the risks for heart disease," said Dr. Fred Cobb.

The heart CT scan detects calcification and plaque built up years before symptoms appear.

"Symptoms are really late manifestations of heart disease. If you wait until symptoms develop, the disease is usually at an advanced stage," Cobb said.

For example, if a patient feels fine, but a CT scan shows large amounts of plaque, Cobb says "This is the patient who frequently would go for further testing."

Studies show the comprehensive approach is an earlier and more accurate predictor of heart disease.

The typical patient who comes in for testing is over 40 and in good health with maybe a few risk factors for heart disease.

At age 44, Squire fits that mold. Fortunately, tests put his risk of heart disease near zero.

"I bet 99.5 percent of people who do this find nothing, but that's the whole point," he said.

The CT heart scan costs around $500. Squire's employer picked up half the cost as part of his physical, but most people pay out of pocket.

For more information on the Duke Program for Prevention and Treatment of Heart Disease call (919)660-6771.