If you or a loved one are experiencing frightening symptoms that could be heart disease, such as chest pain, difficulty breathing, fatigue, shoulder, neck or jaw pain, palpitations or dizziness, you might be relieved when a doctor sends you for a test called a CT angiogram instead of a stress test. Unlike a stress test, a CT angiogram allows a doctor to actually see the heart’s arteries and identify blockages. You might think that such a test is more accurate than a stress test. But it turns out that the long-term results using this test are no different from conventional stress tests and, in fact, a CT angiogram is potentially riskier and significantly more expensive.
CT angiography is similar to regular CT scanning and is a newer application of this technology. Doctors did not know whether CT angiography was better than stress testing to diagnose risk for coronary artery disease—a buildup of plaque in the heart’s arteries that can result in heart attack. But a team of researchers from Duke University and Harvard Medical School found that CT angiography was no better than stress testing in predicting coronary artery disease.
The researchers recruited 10,000 patients with symptoms typically associated with coronary artery disease, most commonly chest pain or trouble breathing with exertion. Half of the participants were randomly assigned to get traditional stress tests, and the other half to get CT angiography. After these procedures, patients were given whatever medical or surgical therapies were recommended based on their test findings and followed up at 60 days and then every six months until the end of the study for a minimum of one year. The researchers’ aim was to see whether CT angiography led to better prevention of cardiovascular events than stress testing. “Cardiovascular events” included fatal or nonfatal heart attack, urgent hospitalization for chest pain or any major complication related to cardiovascular disease or diagnostic testing (such as stroke or kidney failure).
The results: Most of the patients—94%—were followed for at least a year, but some were followed for more than four years. At one year, the rates of cardiovascular events for both groups were identical—3%. And even looking at the rate of cardiovascular events at a median follow-up of two years (taking into account the patients who were followed longer), there was still no difference.
CT angiograms do have a place in the diagnosis of coronary artery disease. When stress tests show a potential problem, patients are more likely to undergo invasive cardiac catheterization, which often does not show significant blockages. In those cases, a CT angiogram, which would have shown the lack of blockages, has a safety advantage. And CT angiograms expose patients to less radiation than nuclear stress testing, another kind of stress test that takes a picture of the heart.
But having a CT angiogram did expose some patients to more radiation than those for whom the alternative was a treadmill stress test, which includes exercise (usually walking briskly on a treadmill) or receiving a medication to affect the heart’s functioning while being hooked up to an electrocardiogram (or echocardiogram) and a blood pressure monitor. This kind of stress test does not expose patients to the potential dangers of ionizing radiation at all.
The new research underscores that CT angiograms aren’t right for everyone and, when all is said and done, they don’t necessarily lead to better outcomes when it comes to the real goal—preventing cardiovascular events such as heart attacks.
