Coronary CT angiography is superior to stress myocardial perfusion imaging for assessing plaque characteristics associated with invasive fractional flow reserve, researchers reported Thursday. It may be enough to reduce reliance on invasive testing.
That’s according to an analysis of more than 600 patients included in a trial investigating CT-based atherosclerotic determinants of coronary artery disease. The results, published in JAMA Cardiology, showed that comprehensive CCTA measures bolster the prediction of vessel-specific coronary physiology compared to typically used myocardial perfusion.
“These findings capture the instability thought to be associated with more lipid-rich, atherosclerotic plaque and reveal the importance of vessel size as an important marker of FFR abnormality,” Wijnand J. Stuijfzand, MD, with New York-Presbyterian Hospital’s radiology department, and colleagues wrote.
“Given this, identification of CCTA atherosclerotic plaque with coronary stenosis findings may provide sufficient evidence to guide preventive treatment and reduce the need for confirmatory functional testing or even use of invasive FFR,” the group added later.
For their study, Stuijfzand et al. set out to compare the accuracy of obstructive and nonobstructive atherosclerotic plaque with functional imaging metrics for predicting FFR in specific vessels. In total, 612 patients with signs of myocardial ischemia were included from across 23 centers. Individuals were part of the larger CREDENCE trial.
Results showed an invasive FFR of 0.80 or less—the primary measure of the study—in 26.5% of 1,727 vessels. CCTA factors associated with this mark included: stenosis severity, percentage of noncalcified atheroma volume, lumen volume, the number of lesions with high-risk plaque, and the number of lesions with stenosis greater than 30%.
“This supports the intriguing findings of atherosclerotic plaque precursors of symptoms or ischemia in the setting of nonobstructive CAD,” the authors noted. “In combination with the characteristic features of high-risk plaque, previously shown to predict acute coronary syndromes and major CAD events, we have identified factors that define vessel instability and potentially identify patients who may benefit from intensive preventive care resulting in improved outcome as compared with standard care approaches.”
Stuijfzand and colleagues also reported that, in the validation group, the areas under the receiver operating characteristic curve were 0.81 for CCTA versus 0.67 for myocardial perfusion imaging.
Future studies, they noted, should include a broader set of atherosclerotic plaque findings to assess arterial blood flow changes that occur when arteries narrow.