Increased CAC levels may predict sudden cardiac death beyond traditional risk factors

Sudden cardiac death (SCD) is a sudden, unexpected death caused by loss of heart function (sudden cardiac arrest). Sudden cardiac death is the largest cause of natural death in the United States, causing about 325,000 adult deaths in the United States each year, its initial manifestation of coronary heart disease however, risk prediction remains elusive.

A recent study by Alexander C. Razavi and team reported that high Coronary artery calcium (CAC) levels is strongly associated with incident sudden cardiac death beyond traditional risk factors. This scaliness can be useful to know the early stages of cardiac heart disease (CHD) through the measurement of CAC. The findings are published in JACC: Cardiovascular Imaging.

Study included 66,636 primary prevention patients from the CAC Consortium. Multivariable competing risks regression and C-statistics were used to assess the association between CAC and SCD, adjusting for demographics and traditional risk factors.

The results of the study were

• The mean age of participants was 54.4 years old, 33% were female, 11% were of non-white ethnicity, and 55% had CAC >0. A total of 211 SCD events (0.3%) were observed during a median follow-up of 10.6 years, 91% occurring among those with baseline CAC>0.

• Compared to CAC=0, there was a stepwise higher risk (p-trend <0.001) in SCD for CAC 100-399 (SHR =2.8, 95% CI: 1.6-5.0), CAC 400-999 (SHR =4.0, 95% CI: 2.2-7.3), and CAC >1000 (SHR =4.9, 95% CI: 2.6-9.9).

• CAC provided incremental improvements in the C-statistic for the prediction of SCD among individuals with a 10-year risk <7.5% (ΔC-statistic=+0.046, p=0.02) and 7.5-20% (ΔC-statistic=+0.069, p=0.003), which were larger when compared to persons with a 10-year risk >20% (ΔC-statistic=+0.01, p=0.54).

Razavi and team concluded that "Higher CAC burden strongly associates with incident SCD beyond traditional risk factors, particularly among primary prevention patients with low-intermediate risk. SCD risk stratification can be useful in the early stages of CHD through the measurement of CAC, identifying patients most likely to benefit from further downstream testing."

Reference: 10.1016/j.jcmg.2022.02.011