Aims: 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.
Methods and results: 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).
Conclusion: 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.
Keywords: acute coronary syndrome; computed tomographic angiography; prognosis.