Calcified Coronary Artery Disease: Pathology, Prevalence, Predictors and Impact on Outcomes

Calcified coronary artery disease is a common clinical finding and is visible angiographically in 25-30% of patients presenting for percutaneous coronary intervention. The presence of coronary calcium, even without coronary artery obstruction, confers an adverse clinical prognosis. Coronary calcium score on CT is additive in predicting risk of cardiovascular events beyond traditional scoring systems. Deposition of calcium in coronary arteries is initiated by the formation of an atherosclerotic plaque. Thereafter, multiple processes and pathways are involved, resulting in initial microcalcifications that coalesce into calcium sheets. Calcified nodules are thought to occur from rupture of these sheets. Calcified coronary stenoses requiring revascularisation result in greater target lesion failure and overall major adverse cardiovascular events than noncalcified lesions, regardless of the mode of revascularisation. Modifying calcium prior to stenting to optimise stent expansion is required and intracoronary imaging can greatly facilitate not only the detection of coronary calcium, but also the confirmation of adequate modification and stent optimisation. In this review, the authors examine the pathophysiology, prevalence, predictors and impact on outcomes of coronary calcium.