Heart health: tool brings people out of the ‘gray zone’

A picture is worth a thousand words, especially if it’s of your arteries, suggests a new study published in the July issue of Clinical Cardiology.

By non-invasively imaging the thickness of carotid arteries — the major vessels running up the neck and supplying the brain with blood — UW preventive cardiologists have helped to show people a clearer picture of their chances of developing heart disease or having a stroke.

Many middle-aged Americans fall into a gray zone when physicians assess their risk factors for developing heart problems, says James Stein, a cardiologist and associate director of the UW Health Heart and Vascular Care Preventive Cardiology Program.

Depending on a number of factors, including cholesterol, blood pressure, weight, age, smoking and family history, Stein says most people at intermediate risk have between a 6 and 20 percent chance of experiencing heart problems within the next decade of their lives.

These individuals, he adds, must decide whether the risk is great enough to go beyond making significant lifestyle changes (such as losing weight, eating healthier and quitting smoking) and start taking medication. “It’s a tough decision,” says Stein, explaining that people at intermediate risk could have to take a medicine for the rest of their lives, sometimes up to 40 years. These medications are expensive and can have side effects.

To help people, especially those with an intermediate risk of developing heart problems, to make more-informed decisions about heart health, Stein introduced a new tool into his clinic. It relies on standard ultrasound equipment and software to measure the thickness of the carotid artery walls. Thicker walls, he explains, increase the chance of heart attack or stroke.

Although widely used as a research tool and recommended by the American Heart Association for certain patients, Stein explains that using ultrasound to measure carotid-artery-wall thickness in a clinical setting is relatively new, primarily because it requires training and some additional software. Stein’s clinic currently offers a program to train health care professionals to perform carotid-artery-wall thickness exams and measurements.

After measuring wall thickness, Stein uses mathematical equations he developed and patented to convert the wall thickness values into a “vascular age,” or the age at which a person in normal health would have that particular reading. For example, a 45-year-old woman whose carotid artery walls are as thick as those of the average 65-year-old woman has a vascular age of 65 years.

As of July 2004, more than 400 people referred by their local physicians have passed through Stein’s screening program. Although the findings presented in the Clinical Cardiology paper are based on the first 82 patients, the results suggest that this diagnostic tool can bring people out of the “gray zone” and provide them with additional information to determine the treatment program right for them.

For example, when Stein measured carotid-artery thickness and calculated the corresponding vascular age for the first group of patients, the picture changed dramatically. While age based on birthdays averaged 55 years, vascular age based on artery-wall thickness averaged about 65 years, suggesting higher risk. Based on vascular age, wall thickness and other risk factors, the overall results showed that 37 subjects had greater chances of developing heart problems, while 17 had lower chances.

“For about two-thirds, the risk was higher than what we expected and, for about one-third, it was lower,” says Stein. He adds that about half of the people at intermediate risk moved up or down a risk level, leading to recommended changes in therapy.

Unlike other techniques for determining heart health, which simply plug numbers into a set of equations, Stein says this one may have a more-lasting effect. Those who underwent this screening, including Stein’s parents, have made significant lifestyle changes perhaps not made otherwise.

“Here, we show them a picture of their own arteries and what they’re supposed to look like. That can be a powerful motivator,” says Stein. “Also, it predicts not just heart attacks, but strokes, which can be devastating.”

Stein points out, too, that the standard prediction methods rely heavily on chronological age, oftentimes underestimating the risk of younger individuals whose families have a history of heart problems.

“Physicians are always interested in improving their ability to assess risk in patients using safe and relatively inexpensive techniques,” says Stein. “This research shows that you can measure carotid-artery-wall thickness in a clinical setting and alter people’s risk prediction, helping them make better decisions about their health.”