Coronary CT angiography (CCTA) is effective for determining the risk of heart attacks and other major adverse cardiovascular events in patients with suspected coronary artery disease (CAD) but no treatable risk factors, according to a study published Feb. 19 in Radiology. 

The absence of CAD at CCTA is associated with a very low risk of adverse events, regardless of age, sex or pretest likelihood of CAD, according to Jonathon A. Leipsic, MD, chairman of the radiology department for Providence Health Care and vice chairman of research for the radiology department at the University of British Columbia in Vancouver, Canada, and colleagues.

“These findings suggest a potential need for refinement of the evaluation of individuals whose disease may be missed by traditional methods of CAD evaluation,” wrote the authors.

Treatment for heart disease is typically based on addressing modifiable clinical risk factors such as high cholesterol or high blood pressure. However, Leipsic and colleagues noted that there isn’t a clinical risk score addressing the incidence of adverse cardiac events in stable patients suspected of having CAD.

“Given the imperfect nature of traditional CAD risk factor scoring, numerous additional adjunctive tests have been investigated to determine the additive predictive value of identifying individuals at risk for [major adverse cardiac events]—including biomarkers and imaging tests—in both asymptomatic and symptomatic individuals,” wrote the authors.

Leipsic and colleagues sought to use CCTA to assess risks for patients with suspected CAD but without medically modifiable risk factors. They conducted an international, multicenter analysis of over 27,000 subjects undergoing CCTA using data collected from the CONFIRM (Coronary CT Angiography Evaluation For Clinical Outcomes: An International Multicenter) registry. The final study group included 5,262 patients with suspected CAD but no medically modifiable risk factors.

Results after an average follow up of 2.3 years showed that of the patients with suspected CAD but no modifiable risk factors, 104 experienced a major adverse cardiovascular event. Despite the absence of modifiable risk factors, the authors identified a high prevalence of CAD in the study group. More than 25 percent of these patients had non-obstructive disease and 12 percent had obstructive disease with greater than 50 percent narrowing in a coronary artery.

Symptomatic and asymptomatic patients with obstructive disease had an increased risk for a major cardiac event, with more severe CAD at CCTA being associated with greater risk. Absence of CAD on CCTA was associated with a very low risk of a major event.

The study authors said their data are not intended to suggest modification of appropriate use criteria, but to provide an understanding of the prevalence of disease and the prognostic value of CAD at CCTA in a unique patient population.

“CCTA should be considered as an appropriate first-line test for patients with atypical chest pain and suspected but not confirmed coronary artery disease,” Leipsic said in a release.