Adding Coronary Calcium Score to Traditional Risk Factors Improves Heart Disease Risk Assessment

Including a coronary artery calcium score in a risk assessment for future heart disease events, such as heart attacks, provides a better estimate in some populations than a standard coronary risk factors assessment, according to research supported by the National Heart, Lung, and Blood Institute (NHLBI).

A coronary artery calcium score was most helpful for people considered to be at intermediate risk of a heart disease—defined as those with a 3% to 10% chance of developing heart disease over the next five years—according to the report in The Journal of the American Medical Association.

In the Multi-Ethnic Study of Atherosclerosis (MESA), researchers used cardiac CT scans, which detect specks of calcium in the walls of the coronary arteries. These specks, indicating calcifications, are an early sign of coronary artery disease, or heart disease.

"This study adds to our knowledge about the possible use of a coronary calcification scan to improve prediction of a patient's risk of heart disease, especially in individuals considered at intermediate, or moderate, risk of heart disease," says NHLBI Acting Director Susan B. Shurin, MD. "However, further evidence is needed to know whether using this test will actually change the course of heart disease and improve patient outcomes."

The study drew from 5,878 MESA participants, aged 45 to 84, who initially did not have known cardiovascular disease, and included both men and women who were white, African American, Hispanic, or of Chinese heritage. Interviewers telephoned participants or a family member at intervals of nine to 12 months to inquire about interim hospital admissions, diagnoses of cardiovascular disease, and deaths.

Participants were followed for almost six years. Over the follow-up period, 209 participants experienced a heart disease event, such as heart attack, death from heart disease, or cardiac arrest.

Using the coronary artery calcium score in addition to standard risk factors accurately placed 77% of the overall population into the highest or lowest risk categories, compared with only 69% assessed with traditional risk factors alone.

The risk assessment with the coronary calcium score reclassified a notable proportion of participants to a more accurate risk classification. An additional 23% of those who experienced events were reclassified to high risk, and an additional 13% who did not experience an event were appropriately reclassified to low risk.

The MESA findings indicate that a coronary artery calcium score may not be an efficient screening tool among low-risk individuals. It is generally accepted that patients who are at high risk should be treated regardless of their coronary artery calcium score, and as a result do not need coronary artery calcium testing for additional risk assessment.

Source: National Institutes of Health