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

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