Imaging Can Detect CAC, Predict Mortality

July 14, 2015

Imaging with electron beam tomography or CT helps determine plaque build-up in coronary artery calcification among asymptomatic patients.

Coronary artery calcification imaging determines plaque build up and accurately predicts 15-year mortality among asymptomatic patients, according to a study published in the Annals of Internal Medicine.

Researchers from Georgia, New York, Maryland, California, Pennsylvania, and Tennessee performed a study to determine the extent of coronary artery calcification (CAC) and near-term adverse clinical outcomes are associated over a follow-up period of five years.

A total of 9,715 patients (3,950 women) participated in the study; 6,672 had a family history of coronary heart disease, 4,220 had hypertension, 6,077 had dyslipidemia, and 810 had diabetes. There were 3,817 smokers in the group. All were asymptomatic and underwent CAC imaging using electron beam tomography or multislice computed tomography. The primary end point was time to all-cause mortality. Median follow-up was 14.6 years and during this period, 936 patients were confirmed as dead.

The results showed that the CAC score was highly predictive of all-cause mortality. The patients were grouped by their resulting number in the following configuration: zero, one-10, 11-99, 100-399, 400-999, and more than 1,000. The 15-year mortality rates ranged from 3% to 28% for patients with CAC scores from 0 to 1,000 or greater. “The relative hazard for all-cause mortality ranged from 1.68 for a CAC score of 1 to 10 to 6.26 for a score of 1,000 or greater,” the authors wrote. “The categorical net reclassification improvement using cut points of less than 7.5 percent to 22.5 percent or greater was 0.21.”

“All high-risk individuals - irrespective of their symptom status - should be considered for this study. It is like a mammogram for the heart,” coauthor James K. Min, MD, the Dalio Institute of Cardiovascular Imaging at New York-Presbyterian Hospital and Weill Cornell Medical College, and professor of radiology and of medicine at Weill Cornell, said in a release. “If physicians can accurately predict who is at risk, they can intervene earlier and more aggressively and hopefully prevent patients from ever having a heart attack.”