Abstract P370: Association of Coronary Calcium on Non-gated 6mm Chest CT with Mortality

Abstract

Background: Coronary artery calcification (CAC) predicts cardiovascular disease (CVD), but imaging to measure CAC is not covered by most insurance providers. Standard 6mm non-gated chest computed tomography (CT) is commonly performed for other clinical indications. Our objective was to compare the association between CAC scores on 3mm ECG gated cardiac CT to standard 6mm non-gated chest CT with risk of death. Methods: Between 2000-03, 4,544 community-living individuals self-referred for “whole body” CT scans had both a 3mm gated cardiac CT and 6mm non-gated chest CT and were followed for mortality through 2009. In this nested case-control study, we selected 173 cases who died, and age and gender frequency matched controls. CAC was scored by the Agatston method on both scans. Unconditional logistic regression determined odds of mortality. Results: The mean age was 68 years and 37% (257 of 691) were women. Spearman correlation of CAC scores between 6mm non-gated chest CT and 3mm gated cardiac CT was 0.79 (p 300 compared to the 3mm gated cardiac CTs. Compared to those without CAC, those with CAC >300 on 6mm non-gated CT scans were at 2.8-fold greater odds of mortality, while those with CAC >300 on 3mm gated CT scans had 1.8-fold greater odds in adjusted models (Table). As a continuous predictor (per 1SD higher Ln[CAC+1]), each SD higher CAC score had 1.50-fold (95% CI 1.20, 1.88) greater odds of death on 6mm chest CT and 1.27 (1.04, 1.55) on 3mm cardiac CT. Conclusions: CAC scores on non-gated 6mm chest CT are strongly correlated with 3mm gated cardiac CT and provide similar information about mortality risk. If confirmed, the many chest CTs done for other clinical purposes may provide valuable information on CVD risk.