Calcium Score and Long-Term ASCVD Outcomes
What is the long-term risk of death and atherosclerotic cardiovascular disease (ASCVD) outcomes, including stroke, in a real-world cohort that underwent coronary artery calcium (CAC) scoring?
The investigators analyzed a total of 23,637 consecutive subjects without ASCVD who underwent CAC scoring from 1997 to 2009. Subjects were assessed for myocardial infarction (MI), stroke, major adverse cardiovascular events (MACE) (e.g., MI, stroke, or cardiovascular death), and all-cause mortality. Outcomes were extracted from the Military Data Repository and the National Death Index and assessed using Cox proportional hazards models, controlling for baseline risk factors, atrial fibrillation, and competing mortality.
Patients (mean age 50.0 ± 8.5 years) were followed over a median of 11.4 years. The relative adjusted subhazard ratio (aSHR) for CAC 1-100, 101-400, and >400 was 2.2, 3.8, and 5.9 for MI; 1.2, 1.4, and 1.9 for stroke; 1.4, 2.0, and 2.8 for MACE; and 1.2, 1.5 and 2.1 for death (p < 0.0001). The addition of CAC score to risk factors significantly improved the prognostic accuracy for all outcomes by the likelihood ratio test. Area under the curve increased from 0.658 to 0.738 for MI, 0.703 to 0.704 for stroke, 0.685 to 0.705 for MACE, and 0.759 to 0.767 for mortality. Among subjects without traditional risk factors (n = 6,208; mean age 43.8 ± 4.4 years), the presence of any CAC (>0; n = 848) was associated with an increased risk of MACE (aSHR, 1.67; 95% confidence interval, 1.16-2.39).
The authors concluded that CAC scoring significantly improved long-term prognostic accuracy for MACE events and mortality, regardless of age and risk factors.
This large-scale, observational study reports that the presence and severity of CAC were superior to traditional risk factors for the prediction of important ASCVD outcomes and all-cause mortality over a median of 11.4 years in a lower-risk, real-world cohort. Of particular clinical significance is the evaluation of CAC for improving long-term risk prediction among young subjects, especially those without a high burden of cardiovascular risk factors who would not typically qualify for preventive therapies (e.g., statins). These data suggest that calcium scoring may significantly improve the assessment of individual cardiovascular risk and better guide the application of preventive therapies. Additional studies assessing the impact on hard clinical outcomes of an image-guided prevention strategy will further solidify the role of CAC in primary prevention.
Keywords: Atherosclerosis, Atrial Fibrillation, Diagnostic Imaging, Myocardial Infarction, Myocardial Ischemia, Outcome Assessment (Health Care), Plaque, Atherosclerotic, Primary Prevention, Risk Factors, Stroke, Vascular Diseases
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