Coronary artery calcium evaluation with chest CT strongly linked to severity of coronary disease and mortality

Researchers aimed to determine the correlation between coronary artery calcium (CAC) scores on 3mm ECG-gated computed tomography (CT) scans and standard 6mm chest CT scans, and to compare relative strength of associations of CAC on each scan type with mortality risk.

Coronary artery calcification predicts cardiovascular disease (CVD) and all-cause mortality, and is typically measured on ECG-gated 3mm CT scans. Patients undergo standard 6mm chest CTs for various clinical indications much more frequently, but CAC is not usually quantified. To better understand the usefulness of standard chest CTs to quantify CAC, we conducted a case-control study among persons who had both scan types.

Between 2000–03, 4,544 community-living individuals self- or physician-referred for “whole body” CT scans, had 3mm ECG-gated CTs and standard 6mm chest CTs, and were followed for mortality through 2009. In this nested case-control study, we identified 157 deaths and 494 controls frequency matched (1:3) on age and gender. The Agatston method quantified CAC on both scan types. Unconditional logistic regression determined associations with mortality, accounting for CVD risk factors.

Participants were 68±11 years old and 63% male. The Spearman correlation of CAC scores between the two scan types was 0.93 (p<0.001); median CAC scores were lower on 6mm CTs compared to 3mm CTs (22 vs.104 Agatston units, p<0.001). Adjusted for traditional CVD risk factors, each SD higher CAC score on 6mm CTs was associated with 50% higher odds of death (OR=1.5; 1.2–1.9), similar to 50% higher odds on the 3mm ECG-gated CTs (OR=1.5, 1.1–1.9).

CAC scores on standard 6mm chest CTs are strongly correlated with 3mm ECG-gated CTs and similarly predict mortality in community-living individuals. Chest CTs performed for other clinical indications may provide an untapped resource to garner CVD risk information without additional radiation exposure or expense.

Reference:

Hughes-Austin JM, Dominguez A 3rd, Allison MA, Wassel CL, Rifkin DE, Morgan CG, Daniels MR, Ikram U, Knox JB, Wright CM, Criqui MH, Ix JH. Relationship of Coronary Calcium on Standard Chest CT Scans With Mortality. JACC Cardiovasc Imaging. 2016 Feb;9(2):152-9. doi: 10.1016/j.jcmg.2015.06.030. Epub 2016 Jan 6. PMID: 26777213; PMCID: PMC4744104.

Keywords:

JACC Cardiovasc Imagin, Coronary artery calcium, Chest Computed Tomography, Mortality, Epidemiology, Hughes-Austin JM, Dominguez A 3rd, Allison MA, Wassel CL, Rifkin DE, Morgan CG, Daniels MR, Ikram U, Knox JB, Wright CM, Criqui MH, Ix JH