Prognosis of vulnerable plaque on computed tomographic coronary angiography with normal myocardial perfusion image

Increasing clinical evidence has emphasized the importance of coronary plaque characteristics, rather than the severity of luminal narrowing on acute coronary syndrome (ACS) outcome. Computed tomographic coronary angiography (CTCA) is a unique, non-invasive approach for assessing plaque characteristics. This study was prospectively designed to investigate the prognostic value of physiologically non-obstructive but a vulnerable coronary plaque on CTCA for predicting future ACS events.

This study consisted of 543 patients who had undergone CTCA and had normal findings on exercise-stress myocardial perfusion single-photon emission computed tomography. CTCA analysis included the presence of >50% luminal stenosis and vulnerable features including positive remodelling (PR), low-attenuation plaque, and ring-like sign. The primary endpoint was ACS events including cardiac death, non-fatal myocardial infarction, and unstable angina. The mean follow-up period was 3.4 ± 0.8 years. The 3-year cumulative event rate was 1.2% per year, and 87% of ACS events occurred in plaques with at least one of vulnerable features. In patient-based multivariate analysis, the presence of plaque with vulnerable features on CTCA was a significant predictor for future ACS events (P = 0.001). Patients with vulnerable plaque had worse ACS outcomes compared with those without vulnerable plaques (3-year cumulative event rate; 3.2 per year vs. 0.8%, P < 0.001).

This study demonstrated that physiologically non-obstructive but vulnerable coronary plaques were associated with future ACS events. We should pay more attention to currently non-obstructive plaque but showing vulnerable morphologies on CTCA.