Physiological correlates of densely calcified coronary lesions on coronary computed tomography angiography among patients with low-to-intermediate coronary artery disease likelihood

Abstract

Coronary computed tomography angiography (CCTA) is often used to assess the extent and severity of atherosclerosis. A major limitation of CCTA are densely calcified coronary plaques that obscure the underlying lumen rendering assessment difficult. The purpose of this study was to evaluate the hemodynamic importance of densely calcified coronary lesions on CCTA in patients with low-to-intermediate likelihood of coronary artery disease. We studied 92 patients (64±10 years, 75% men) who underwent CCTA and stress perfusion cardiovascular magnetic resonance (CMR). Coronary stenoses were categorized as none, less than 50%, 50-70%, and greater than 70%, or densely calcified. Coronary arteries were considered densely calcified if the artery had a calcified lesion obscuring the underlying lumen and did not have another stenosis of greater than 50%. CMR was considered abnormal if there was reversible ischemia or myocardial scar determined by the presence of late gadolinium enhancement. Among the 92 patients, 271 vessels were analyzed of which 44 (16%) were considered densely calcified. Among these 44 coronary territories, six (14%) had abnormal CMR findings. On a per-vessel analysis, a proportional increase in the number of myocardial segments with reversible ischemia or the presence of late gadolinium enhancement was associated with an increase of CCTA stenosis ranging from 2% in patients without coronary plaque to 70% in patients with a greater than 70% stenosis (P<0.0001). In conclusion, the vast majority (86%) of densely calcified lesions were not hemodynamically significant in our study. As our study was in patients with relatively low-to-intermediate likelihood of coronary artery disease, a prospective study is warranted to assess if our findings are generalizable to other patient populations.