Associations of segment-level coronary calcium scoring metrics with major and minor cardiovascular events

Background Coronary artery calcium (CAC) scoring is a well-established method for the non-invasive assessment of coronary artery calcification. Although its potential for clinical risk prediction has been discussed numerous times, there is limited evidence on the assessment of calcification at the coronary artery segment level. Methods This prespecified analysis of the DISCHARGE Trial (NCT02400229) included patients who received a calcium scoring CT and showed presence of coronary calcification. The diffusivity index and risk groups derived from that index, and the number of calcified segments were extracted. The association with major adverse cardiovascular events (MACE) and minor adverse cardiovascular events (MICE) was assessed. Results This study included 833 patients. During a median follow-up of 3.5 years, 26 (3.1%) patients experienced MACE and 106 (12.7%) experienced MICE. The Kaplan-Meier analysis showed a higher cumulative incidence of cardiovascular events in patients with high CAC diffusivity. High compared to low CAC diffusivity was associated with an approximately 4.5-fold increase in risk of MACE. There was a 3% increase in risk per diffusivity index unit. The CAC diffusivity index and risk groups were only significantly associated with MICE when adjusted for the total Agatston score and not for the CAC risk groups (Agatston 1–399 or ≥400). There was no evidence of a statistically significant interaction between segment-level metrics and sex. Conclusion CAC diffusivity metrics were significantly associated with MACE beyond traditional scoring methods, whereas their association with MICE was weak. The number of calcified segments was only significantly associated with MICE.