Article Print

Maybe a close relative died of a heart attack at 45 and you are now approaching middle age, or maybe you're starting an exercise program after 10 years of a mostly sedentary lifestyle. Either way, you'll want to know what your risk of heart disease is even if you don't have any symptoms of heart disease, such as chest pain.

Two recently published studies offer new information about whether it's helpful for people without symptoms to get an exercise stress test, where the heart is monitored while you walk or run on a treadmill or ride a stationary bicycle. Although these tests are often given to healthy people, the American Heart Association, the American College of Cardiology and other leading organizations only recommend stress tests for men and women with obvious heart disease because of a lack of evidence that they are useful in the general population.

"We asked whether the exercise test can detect disease at an early stage before it can cause symptoms and when we can do something to prevent trouble," says Michael S. Lauer, a professor of medicine at the Cleveland Clinic Lerner College of Medicine and lead author of one of the studies, published in the September 22th issue of The Journal of the American Medical Association.

Rating Risk Factors
When assessing heart disease risk in their healthy patients, doctors first look at the major risk factors for heart disease such as age, gender, blood pressure, diabetes, cholesterol and smoking status.

"We come up with the patients who are at greatest risk, and then we look at additional risk factors, such as whether or not they're postmenopausal, if they're women, or whether they have high C-reactive protein, which is a marker in the blood believed to reflect an increased risk of heart disease," says Kelly Spratt, DO, an clinical assistant professor at the University of Pennsylvania and a cardiologist in Penn's Cardiovascular Risk Intervention Program.

The Exercise Stress Test
The next step in assessing risk may be an exercise stress test. By looking at your heart under stress, doctors can measure how well the heart works and if there is adequate blood flow to the heart. A poor result may suggest someone has an irregular heartbeat or is out of shape, or that there is blockage in the arteries and that the person has coronary heart disease. If the artery blockage is confirmed with other tests, the person may undergo procedures such as angioplasty, stenting or bypass surgery to treat their heart disease.

Who Does It Help?
The exercise stress test has not received a unanimous vote as a cardiovascular screening test in healthy people. The two new studies, however, suggest that the exercise stress test may help determine heart disease risk in people without symptoms or heart disease, as long as they are already considered high risk based on their risk factors. The JAMA study included more than 35,000 men and women between 50 and 75 who did not have symptoms of heart disease. The patients' risk was assessed with either the Framingham Risk Score, which estimates someone's 10-year risk of a heart attack or death from heart disease by weighing risk factors, or the European scoring system, known as SCORE, which uses a different equation than the Framingham Score to calculate risk.

The researchers found that the exercise stress test, if used in conjunction with SCORE or the Framingham Risk Score, may be helpful in determining heart disease risk. So in patients with multiple risk factors, normal results on the exercise stress test might drop them down to intermediate risk while abnormal results might bump them up to very high risk.

"We did find that that the exercise test was useful for some people," Dr. Lauer says. "But not for everybody. The decision to get a test is not something to be taken lightly because in someone at low risk for heart disease, the test can give you misleading information and subject people to further tests and anxiety that are not appropriate."

For example, if a 40-year-old person who is a non-smoker with low cholesterol and low blood pressure may be at low risk even if the test showed they were at high risk.

The other study, published in the September 28th issue of Circulation: Journal of the American Heart Association, looked at more than 3,000 men and women without heart disease symptoms. The researchers found that the treadmill test was a good predictor of risk in men with multiple risk factors; there were not enough women in the study to evaluate the exercise test.

Dr. Lauer says the best way to figure out how the exercise test should be used is with a large, randomized trial where one group of healthy people receives the test and other group does not. A similar trial design helped determine the usefulness of mammograms for the detection of breast cancer.

Bottom Line? Know Your Risk.
Whether or not the exercise stress test is right for you, cardiologists say, it's valuable to know your risk by learning your cholesterol, blood pressure and blood sugar numbers—and quitting smoking. "Uncovering previously unknown heart disease can help a person change their behavior and adopt a more healthy lifestyle," says Dr. Spratt. And with a largely preventable illness like coronary heart disease, a healthy lifestyle, as well as blood pressure or cholesterol medicines when appropriate, can lead to a longer and healthier life.