Coronary CT angiography (CCTA) does a better job than functional cardiac testing of predicting future cardiac events among individuals with chest pain, according to new results published June 13 in Circulation from the Prospective Multicenter Imaging Study for Evaluation of Chest Pain (PROMISE).
CCTA was able to identify a large group of at-risk patients with nonobstructive coronary artery disease who might have been missed had they received functional stress testing, according to a team led by Dr. Udo Hoffmann from Massachusetts General Hospital. In addition to affecting the decisions physicians make in referring patients for additional tests, the findings could also support lifestyle changes and the use of statins for at-risk patients.
PROMISE was performed at 193 centers across North America. The study was designed to compare two strategies for guiding treatment decisions for patients with chest pain: starting with CCTA, or starting with functional measures such as stress testing and echocardiography. A 2015 paper in the New England Journal of Medicine found that both strategies produced similar outcomes in terms of predicting future events.
For the new analysis, the researchers took a subset of 9,100 patients from the more than 10,000 involved in PROMISE. They found that CCTA did a better job than functional testing in identifying individuals with nonobstructive coronary artery disease, which is defined as the narrowing of a coronary artery of less than 70%. Indeed, most of the cardiac events during the study's follow-up period of two years happened in patients who did not have an initial diagnosis of coronary artery obstruction.
The researchers were able to improve the prognostic performance of functional imaging by adding traditional cardiovascular risk factors such as cholesterol levels, blood pressure, and smoking status.
Although this was an observational study rather than a randomized controlled trial, Hoffmann and colleagues believe the results could guide better treatment decisions in the future. Future studies could also determine whether analyzing more exercise parameters in functional tests would improve prognostic ability.