According to research reported in the February 27, 2007, issue of the Journal of the American College of Cardiology (JACC), a computed tomography (CT) scan of the heart can quickly detect whether there are fatty blockages or pockets of rock-hard calcium in the arteries of the heart — clues that coronary artery disease may be the cause of the chest pain.
Imagine coming to the hospital with crushing chest pain, only to find that emergency room doctors are uncertain whether you?re having a heart attack. The electrocardiogram (ECG) is inconclusive and the blood tests that detect heart damage are normal. The only thing to do is wait, hour after hour, as doctors repeat the tests several times and scrutinize the results for diagnostic clues.
Soon, the wait may be much shorter. According to research reported in the February 27, 2007, issue of the Journal of the American College of Cardiology (JACC), a computed tomography (CT) scan of the heart can quickly detect whether there are fatty blockages or pockets of rock-hard calcium in the arteries of the heart?clues that coronary artery disease may be the cause of the chest pain.
“The new 64-slice CT scanners give us amazing pictures of the heart,” said James A. Goldstein, M.D., F.A.C.C., Director of Research and Education in the Division of Cardiology at William Beaumont Hospital, Royal Oak, MI. “With this very simple outpatient scan, you can rapidly determine whether the arteries are normal or abnormal?and if they?re abnormal, whether the disease is mild, moderate, or severe.”
Those who get a clean bill of health can safely go home from the hospital without further testing. “As a physician, it?s tremendously satisfying to tell an anxious patient, within about 30 minutes, that their heart and arteries are normal,” Dr. Goldstein said.
Each year, some 6 million people in the United States are rushed to the emergency room with chest pain. At least half have inconclusive early test results; of these, approximately 65 percent are eventually found not to have suffered a heart attack?but not before racking up diagnostic costs totaling $10 billion to $12 billion annually.
Even low-risk patients with no history of heart disease can spend 18 to 24 hours in the emergency room as doctors repeat the ECG and blood tests. That?s because doctors want never to mistakenly send home a patient who is actually having a heart attack. “The consequences of missing a heart attack can be disastrous,” Dr. Goldstein said. “So even if you appear to be completely healthy, if you come to the emergency room with chest pain, you?re going to go through a very laborious, expensive, and time-consuming evaluation.”
Dr. Goldstein and his colleagues wanted to see whether a CT scan of the heart could make the evaluation of chest pain more efficient and less costly, allowing emergency physicians to quickly send home patients with normal coronary arteries, while accurately identifying patients with serious heart disease who needed to be admitted to the hospital.
For the study, they recruited 197 patients with heart attack-like chest pain but no history of heart disease. In all patients, the results of the ECG and the blood tests that detect heart damage were normal, both initially and after being repeated four hours later. The researchers then randomly assigned half of the patients to have a CT scan of the heart and the other half to a standard diagnostic plan, which included additional rounds of ECG and blood testing, plus a nuclear scan of the heart.
Multislice CT first uses x-rays to measure the amount of calcium in the arteries supplying blood to the heart. Then, after injection of high-contrast intravenous dye, it creates detailed pictures of the heart and coronary arteries, including any soft, cholesterol-filled blockages. The scan takes only minutes to complete.
Nuclear scanning is a two-part test that uses radioactive material to evaluate blood flow to the heart during rest and again during stress, when the heart is pumping faster as the result of exercise or medication. By definition, nuclear imaging takes longer than a CT scan. Most doctors prefer to observe the patient in the emergency room for at least eight hours before stressing the heart, just to be safe. In addition, several hours must pass between the rest and stress portions of the test to allow the radioactive material to pass through the body.
In the new study, patients with a clearly normal CT or nuclear scan were allowed to go home immediately, and those with a clearly abnormal scan were sent to the cardiac catheterization laboratory for further, invasive testing. In the CT group, patients with uncertain test results?either because the images were not clear, or because there was only a moderate amount of disease in the coronary arteries?also had a nuclear scan to help determine whether invasive testing would be needed.
The researchers found that CT alone was able to determine that heart disease was the cause of chest pain?or reliably rule out that possibility?in 75 percent of patients. The remaining 25 percent of patients had a nuclear scan in addition to CT. Even so, both the cost and the time it took to reach a diagnosis were significantly lower in the CT group. Costs averaged $1,586 for patients who had a CT scan, as compared to $1,872 for patients who had a standard diagnostic evaluation (p