Aug. 27, 2003 -- Calcium in the coronary arteries has always been bad news -- signaling the onset of heart disease. But new research shows it could indicate something much more serious: that you could suffer sudden cardiac death within five years.
Often No Warning Signs
Heart disease is the No. 1 killer of American men and women. Massive heart attack is the most common cause of sudden cardiac death. "We know that atherosclerosis [hardening of the arteries] is a disease that infiltrates the arterial wall long before it obstructs blood flow and causes symptoms," says Paolo Raggi, MD, associate chief of cardiology at Tulane University Hospital, in a news release. "Over half of all first coronary heart disease events are sudden cardiac deaths or acute heart attacks in individuals who experienced no previous symptoms."
The study took place over five years, following more than 10,000 asymptomatic people who were referred for cardiac risk factor evaluation and coronary artery screening. They raged from 30 to 85 years old. The findings appear in the September issue of Radiology.
All of the volunteers were above-average risk for coronary disease based on having common cardiac risk factors -- such as family history of heart disease and history of high blood pressure, smoking, or diabetes.
Each underwent an imaging test called electron-beam CT screening to determine whether there was calcium buildup in the coronary arteries. Researchers based their results on this test, medical records, referring physician notes, and patient interviews.
Age, Calcium Scores Increase Risk
The average coronary calcium score was 133. But scores ranged from 12 to 1,070 for men and seven to 291 for women. Little more than half of the total group had scores of 10 and under. The study showed that as the calcium score went up, so did people's chances of having a sudden cardiac death. Compared with people who had scores of 10 or less, the risk of death within five years was:
- 3 times greater for scores of 11-100
- 4 times greater for scores of 101-400
- 6 times greater for scores of 401-1,000
- 12 times greater for scores higher than 1,000
Researchers say age (60 years or older) and coronary calcium were the strongest risk factors of sudden cardiac death in the study. Researchers tacked on a twofold relative risk ratio for smokers and volunteers with high blood pressure.
Raggi says the results of such a large sample can't be ignored. "It is not clear whether the presence of coronary calcium renders plaque unstable, but it does indicate an individual's predisposition to suffer acute coronary events such as stroke and sudden death. ... The results of our study justify using coronary calcium screening to help calibrate the risk more accurately in patients considered to be at immediate risk for heart disease."