The vulnerable calcium index (VCI) was independently associated with major adverse cardiac events per unit increase in the CLARIFY (HR 1.12; 95% CI 1.02-1.22) and SCOT-HEART cohorts.
Cohort (n=2,912)
Yes
Does the vulnerable calcium index (VCI) improve prediction of MACE compared to the conventional Agatston score in asymptomatic individuals and patients with chest pain?
The vulnerable calcium index (VCI) captures sub-Agatston coronary calcification and independently improves MACE prediction beyond the conventional Agatston score in both primary-prevention and symptomatic chest pain populations.
Hazard Ratio: 1.12 (95% CI 1.02–1.22)
p-value: p=0.02
Abstract Aims To develop assessments of low-density (“sub-Agatston”) coronary artery calcification (CAC) on non-contrast CT calcium score (CTCS) examinations to evaluate its association with the risk of atherosclerotic major adverse cardiac events (MACE) and with high-risk plaque (HRP) features from coronary CT angiography (CCTA). Methods We analyzed 1837 asymptomatic individuals from the CLARIFY CTCS registry (NCT04075162) and 1075 patients presenting at chest-pain clinics from the SCOT-HEART trial (NCT01149590). MACE comprised death, myocardial infarction, stroke, or revascularization. We developed the vulnerable calcium index (VCI), which quantifies the proportional CAC mass increase after region-growing from 130 HU (Agatston) to 110 HU. Cox models were adjusted for age, sex, diabetes, hypertension, smoking, baseline statin use, and Agatston score. The association between VCI and CCTA-defined HRP (low-attenuation plaque, positive remodeling, spotty calcifications, mixed plaque, punctate calcification, napkin-ring sign) was assessed in patients with paired CTCS and CCTA in SCOT-HEART. Results Median follow-up was 4.8 y (CLARIFY) and 4.9 y (SCOT-HEART). VCI was independently associated with MACE in both cohorts: CLARIFY (adjusted hazard ratio HR 1.12, 95% CI 1.02–1.22, p=0.02) per unit increase in VCI and SCOT-HEART (adjusted HR 1.16, 1.03–1.31, p=0.02). Patients in the top quartile of adjusted model risk had markedly higher event rates compared with the lowest quartile (CLARIFY HR 25.0; SCOT-HEART HR 33.7 vs Q1, p0.005 for both). Addition of VCI to Agatston significantly improved C-index (CLARIFY: 0.62 to 0.66, p0.001; SCOT-HEART: 0.72 to 0.75, p0.001) and net reclassification index (CLARIFY: 0.52 0.40, 0.64, p0.005; SCOT-HEART: 0.72 0.48, 0.94, p0.005). In SCOT-HEART, VCI was associated with all HRP features (OR: 1.45 to 1.85, p0.001), adjusted for Agatston score. Conclusion VCI captures sub-Agatston CAC linked to HRP and independently improves MACE prediction in both a primary-prevention and a mixed-risk symptomatic chest pain population. Incorporating VCI into CAC reporting may refine preventive risk stratification beyond the conventional Agatston score.
Singh et al. (Sat,) conducted a cohort in Asymptomatic individuals and patients with chest pain (n=2,912). Vulnerable calcium index (VCI) vs. Lower VCI was evaluated on Major adverse cardiac events (MACE) comprising death, myocardial infarction, stroke, or revascularization (HR 1.12, 95% CI 1.02-1.22, p=0.02). The vulnerable calcium index (VCI) was independently associated with major adverse cardiac events per unit increase in the CLARIFY (HR 1.12; 95% CI 1.02-1.22) and SCOT-HEART cohorts.