Arterial calcium a clue to heart attack risk

Even patients who have been told they are not “high-risk patients” may in fact be susceptible if calcium levels are too high, report the researchers at Ludwig Maximilians University in Munich in a report released by the Radiological Society of North America (RSNA).

“The amount of calcium in the coronary vessels, as measured by CT, is of high predictive value for subsequent serious or fatal heart attack in these patients, independent of the patient’s age, sex and other coronary risk factors,” said the study’s lead author, Dr Marcus Hacker, head of the research unit for nuclear cardiology and assistant medical director at the Munich university.

By “scoring” levels of arterial calcium, the Munich researchers found they were able to predict future severe cardiac events in patients with known, stable coronary artery disease (CAD).

Coronary artery disease is a condition in which plaque - cholesterol, calcium, fat and other substances - builds up inside the arteries that supply blood to the heart. CAD is the most common form of heart disease, claiming millions of lives worldwide each year.

Physicians have always wondered why certain “low-risk” patients nonetheless suffered major coronary events. Hacker and his colleagues set out to determine whether calcium “scoring” would help in predicting heart attacks in patients with diagnosed, albeit stable CAD.

For the study, 260 patients with CAD underwent coronary artery calcium scoring in addition to myocardial perfusion imaging.

Over a median period of more than five years, the patients were followed up for severe cardiac events, meaning cardiac death or nonfatal heart attacks. Twenty-three of the 260 patients had a fatal or severe heart attack, and 40 additional patients underwent bypass surgery.

The results showed that patents with an initial calcium score greater than 400 were at significantly increased risk for severe cardiac events, according to the study published in the RSNA journal Radiology.

“We found that coronary calcium seems to play an important role in predicting subsequent heart attack or sudden cardiac death, and adds prognostic value to SPECT findings,” the authors wrote.

Hacker stressed that combining calcium scoring and CT scanning can help to identify patients with known CAD who are at highest risk for serious or fatal heart attacks - and who perhaps do not realize they are at risk.

“In these patients, intensified medical therapy, shorter follow-up intervals and, if necessary, bypass procedures may be required to prevent future severe cardiac events,” he said.