Coronary artery calcium and sudden cardiac death: current evidence and future directions

PURPOSE OF REVIEW: To provide a summary of the current evidence and highlight future directions regarding coronary artery calcium (CAC) and risk of sudden cardiac death (SCD). RECENT FINDINGS: Although up to 80% of all SCD is attributed to coronary heart disease (CHD), the subclinical atherosclerosis markers that help to improve SCD risk prediction are largely unknown. Recent observational data have demonstrated that, after adjustment for traditional risk factors, there is a stepwise higher risk for SCD across increasing CAC burden such that asymptomatic patients without overt atherosclerotic cardiovascular disease (ASCVD) experience a three-fold to five-fold higher SCD risk beginning at CAC at least 100 when compared with CAC = 0. Although the mechanisms underlying increasing CAC and SCD risk have yet to be fully elucidated, risk for myocardial infarction and scar, and/or exercise-induced ischemia may be potential mediators. SUMMARY: High CAC burden is an important risk factor for SCD in asymptomatic middle-aged adults, suggesting that SCD risk stratification can begin in the early stages of CHD via measurement of calcific plaque on noncontrast computed tomography. Despite the clinical inertia for downstream functional cardiac testing after detecting high CAC, comprehensive ASCVD prevention strategies should be the primary focus for SCD risk reduction.