Association of Coronary Artery Calcification and Mortality in the National Lung Screening Trial: A Comparison of Three Scoring Methods

Abstract

Purpose To evaluate three coronary artery calcification (CAC) scoring methods to assess risk of coronary heart disease (CHD) death and all-cause mortality in National Lung Screening Trial (NLST) participants across levels of CAC scores. Materials and Methods The NLST was approved by the institutional review board at each participating institution, and informed consent was obtained from all participants. Image review was HIPAA compliant. Five cardiothoracic radiologists evaluated 1575 low-dose computed tomographic (CT) scans from three groups: 210 CHD deaths, 315 deaths not from CHD, and 1050 participants who were alive at conclusion of the trial. Radiologists used three scoring methods: overall visual assessment, segmented vessel-specific scoring, and Agatston scoring. Weighted Cox proportional hazards models were fit to evaluate the association between scoring methods and outcomes. Results In multivariate analysis of time to CHD death, Agatston scores of 1–100, 101–1000, and greater than 1000 (reference category 0) were associated with hazard ratios of 1.27 (95% confidence interval: 0.69, 2.53), 3.57 (95% confidence interval: 2.14, 7.48), and 6.63 (95% confidence interval: 3.57, 14.97), respectively; hazard ratios for summed segmented vessel-specific scores of 1–5, 6–11, and 12–30 (reference category 0) were 1.72 (95% confidence interval: 1.05, 3.34), 5.11 (95% confidence interval: 2.92, 10.94), and 6.10 (95% confidence interval: 3.19, 14.05), respectively; and hazard ratios for overall visual assessment of mild, moderate, or heavy (reference category none) were 2.09 (95% confidence interval: 1.30, 4.16), 3.86 (95% confidence interval: 2.02, 8.20), and 6.95 (95% confidence interval: 3.73, 15.67), respectively. Conclusion By using low-dose CT performed for lung cancer screening in older, heavy smokers, a simple visual assessment of CAC can be generated for risk assessment of CHD death and all-cause mortality, which is comparable to Agatston scoring and strongly associated with outcome.

2016 SCCT/STR guidelines for coronary artery calcium scoring of noncontrast noncardiac chest CT scans: A report of the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology

“…69 For the second ordinal method, 0 ¼ very low risk, 1e5 ¼ mildly increased risk, 6e11 ¼ moderately increased risk, and 12e30 ¼ moderate to severely increased risk. 68 For visual assessment analysis, none ¼ very low risk, mild ¼ mildly increased risk, moderate ¼ moderately increased risk, and severe ¼ moderately to severely increased risk. 68 Treatment recommendations should parallel the risk classification and are particularly critical in this context since the referring physicians have not requested the CAC scores and are not likely to be familiar with the therapeutic algorithms for each CAC level.…”

“…68 For visual assessment analysis, none ¼ very low risk, mild ¼ mildly increased risk, moderate ¼ moderately increased risk, and severe ¼ moderately to severely increased risk. 68 Treatment recommendations should parallel the risk classification and are particularly critical in this context since the referring physicians have not requested the CAC scores and are not likely to be familiar with the therapeutic algorithms for each CAC level. Formal treatment recommendations, however, are beyond the scope of this guideline; they may be part of forthcoming SCCT Expert Consensus and other documents.…”

“…67 Low dose nongated CT scans were evaluated in 1442 patients in the National Lung Screening Trial. 68 Compared to Agatston scores of 0, scores of 1e100, 101e1000, and greater than 1000 had HR of 1.27 (95% CI: 0.69, 2.53), 3.57 (95% CI: 2.14, 7.48), and 6.63 (95% CI: 3.57, 14.97), respectively.…”

“…68 Categories of CAC on visual estimation are none, mild, moderate and severe. Compared to no CAC, the adjusted HR for coronary heart disease deaths were 2.09 (95% CI:1.…”

Diagnostic accuracy of standard axial 64-slice chest CT compared to cardiac MRI for the detection of cardiomyopathies

“…Dutch and Italian lung cancer CT screening trials have reported the ability of non-cardiacgated chest CT to detect coronary artery disease. [24][25][26] Chiles et al 27 have shown that a global assessment of the volume of calcified coronary artery plaque in smokers undergoing noncardiac-gated chest CTs can help risk stratify patients for coronary heart disease associated mortality. However, there is no evidence that standard axial chest CT has the ability to detect cardiomyopathies per se, and we could not find another published series with which to compare our results too.…”