JACC: CTA might better predict plaque instability for higher risk patients
Patients demonstrating positively remodeled coronary segments with low-attenuation plaques on CT angiography (CTA) were at a higher risk of acute coronary syndrome (ACS) developing over time when compared with patients having lesions without these characteristics, according to a study in the July 30 issue in the Journal in the American College of Cardiology.

The CT characteristics of culprit lesions in ACS include positive vessel remodeling (PR) and low-attenuation plaques (LAP). According to the authors, these two features have been observed in the lesions that have already resulted in ACS, but their prospective relation to ACS has not been previously described

Sadako Motoyama, MD, PhD, from the department of cardiology at Fujita Health University School of Medicine in Toyoake, Japan, and colleagues analyzed atherosclerotic lesions in 1,059 patients who underwent CTA for the presence of two features: PR and LAP. They calculated the remodeling index, and plaque and LAP areas and volumes; and evaluated the plaque characteristics of lesions resulting in ACS during the follow-up of an average of 27 months.

Of the 45 patients showing plaques with both PR and LAP (two-feature positive plaques), the researchers found that ACS developed in 22.2 percent, compared with 3.7 percent of the 27 patients with plaques displaying either feature (one-feature positive plaques).

In only four of the 820 patients with neither PR nor LAP (two-feature negative plaques) did ACS develop, the authors wrote. None of the 167 patients with normal angiograms had acute coronary events.

Motoyama and colleagues reported that ACS was independently predicted by PR and/or LAP (hazard ratio: 22.8). Among two- or one-feature positive segments, they found that those resulting in ACS demonstrated significantly larger remodeling index (126.7 vs. 113.4 percent), plaque volume (134.9 mm3 vs. 57.8 mm3), LAP volume (20.4 mm3 vs. 1.1 mm3) and percent LAP/total plaque area (21.4 mm2 vs. 7.7 mm2) compared with segments not resulting in ACS.

Based on their findings, the researchers concluded that once a patient is identified to be at high risk of having an adverse cardiac event on the basis of traditional clinical, biochemical, and biomarker risk profiles, imaging may help identify those at greater risk of acute coronary events, despite the fact that current appropriateness guidelines do not recommend screening with CTA.