Calcium Scores Best Predictor of Heart Attack Risk

Scans can predict heart attack risk but often create uneccessary worry.

ByABC News
August 18, 2011, 2:40 PM

Aug. 18, 2011— -- Joanne Leahy, 59, of Fort Lauderdale, Fla., followed her cardiologist's recommendation and had a computer tomography, or CT, scan to check her heart attack risk, because of her family history of heart disease.

The procedure, called coronary artery calcium scoring -- or CAC -- checks for calcium buildup in the arteries. It rates heart attack risk and gauges the benefit of certain heart treatments, such as statins.

"It's quick, painless and an indicator of heart attack," Leahy said Dr. Wiliam O'Neill, her cardiologist and chief medical officer at the University of Miami Health System, told her at the time.

Doctors generally use a blood test to check for high levels of C-reactive protein, which can signal artery inflammation and is a potential predictor of a heart attack.

But Leahy's doctor went straight to the CAC scan as his first line of defense.

A study published Thursday in the Lancet now throws some data on O'Neill's confidence. The study suggests that screening for calcium buildup in coronary arteries, called atherosclerosis, may be a better method than a C-reactive protein test, which measures the amount of C-reactive protein in the blood, for not only predicting heart attack risk but whether a patient might benefit from statin therapy.

Researchers looked at 950 patients with no symptoms of heart disease and found that patients with the presence of calcium -– even those with low cholesterol levels -- had twice the risk for heart attack or stroke and four times the risk for heart disease than those with a calcium score of zero.

Statins, cholesterol-lowering medications, are prescribed to prevent or treat plaque buildup that could cause heart attacks. But many are prescribed statins because of such risk factors as age, high cholesterol, diabetes or a family history of heart attacks.

O'Neill said given the study findings, "You have to ask if they [those with no calcium] should be treated with statins."

While calcium scanning is helpful in seeing whether atherosclerosis has started, for many, calcium presence in the arteries does not necessarily indicate heart disease or even a looming heart attack. Studies have yet to show that calcium scans have reduced the risk of heart attack or death from heart disease.

Some experts do not support calcium scanning, saying that a patient may be exposed to high levels of radiation at extra out-of-pocket expense.

"Calcium scanning is one of the worst examples of medicine gone wild," said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic. "It's taken on a 'cultlike' following."