Coronary Artery Calcium Can Predict All-Cause Mortality and Cardiovascular Events on Low-Dose CT Screening for Lung Cancer

Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Universiteitsweg 100, P.O. Box 85060, 3508 AB Utrecht, The Netherlands.
American Journal of Roentgenology (Impact Factor: 2.73). 03/2012; 198(3):505-11. DOI: 10.2214/AJR.10.5577
Source: PubMed


Performing coronary artery calcium (CAC) screening as part of low-dose CT lung cancer screening has been proposed as an efficient strategy to detect people with high cardiovascular risk and improve outcomes of primary prevention. This study aims to investigate whether CAC measured on low-dose CT in a population of former and current heavy smokers is an independent predictor of all-cause mortality and cardiac events.
We used a case-cohort study and included 958 subjects 50 years old or older within the screen group of a randomized controlled lung cancer screening trial. We used Cox proportional-hazard models to compute hazard ratios (HRs) adjusted for traditional cardiovascular risk factors to predict all-cause mortality and cardiovascular events.
During a median follow-up of 21.5 months, 56 deaths and 127 cardiovascular events occurred. Compared with a CAC score of 0, multivariate-adjusted HRs for all-cause mortality for CAC scores of 1-100, 101-1000, and more than 1000 were 3.00 (95% CI, 0.61-14.93), 6.13 (95% CI, 1.35-27.77), and 10.93 (95% CI, 2.36-50.60), respectively. Multivariate-adjusted HRs for coronary events were 1.38 (95% CI, 0.39-4.90), 3.04 (95% CI, 0.95-9.73), and 7.77 (95% CI, 2.44-24.75), respectively.
This study shows that CAC scoring as part of low-dose CT lung cancer screening can be used as an independent predictor of all-cause mortality and cardiovascular events.

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    • "Low-dose non-gated chest CT has been applied for lung cancer screening in smokers [8], [9]. In spite of suboptimal image acquisition, CAC scoring from lung cancer screening CT has been shown to be a strong and independent predictor of cardiovascular events and all-cause mortality [10], [11], [12]. Also, several studies demonstrated good agreement between CAC scores determined using low-dose non-gated CT, as acquired in lung cancer screening, and CAC scores quantified using gated cardiac CT [13], [14], [15]. "
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    ABSTRACT: To determine the agreement and reliability of fully automated coronary artery calcium (CAC) scoring in a lung cancer screening population. 1793 low-dose chest CT scans were analyzed (non-contrast-enhanced, non-gated). To establish the reference standard for CAC, first automated calcium scoring was performed using a preliminary version of a method employing coronary calcium atlas and machine learning approach. Thereafter, each scan was inspected by one of four trained raters. When needed, the raters corrected initially automaticity-identified results. In addition, an independent observer subsequently inspected manually corrected results and discarded scans with gross segmentation errors. Subsequently, fully automatic coronary calcium scoring was performed. Agatston score, CAC volume and number of calcifications were computed. Agreement was determined by calculating proportion of agreement and examining Bland-Altman plots. Reliability was determined by calculating linearly weighted kappa (κ) for Agatston strata and intraclass correlation coefficient (ICC) for continuous values. 44 (2.5%) scans were excluded due to metal artifacts or gross segmentation errors. In the remaining 1749 scans, median Agatston score was 39.6 (P25-P75∶0-345.9), median volume score was 60.4 mm3 (P25-P75∶0-361.4) and median number of calcifications was 2 (P25-P75∶0-4) for the automated scores. The κ demonstrated very good reliability (0.85) for Agatston risk categories between the automated and reference scores. The Bland-Altman plots showed underestimation of calcium score values by automated quantification. Median difference was 2.5 (p25-p75∶0.0-53.2) for Agatston score, 7.6 (p25-p75∶0.0-94.4) for CAC volume and 1 (p25-p75∶0-5) for number of calcifications. The ICC was very good for Agatston score (0.90), very good for calcium volume (0.88) and good for number of calcifications (0.64). Fully automated coronary calcium scoring in a lung cancer screening setting is feasible with acceptable reliability and agreement despite an underestimation of the amount of calcium when compared to reference scores.
    Full-text · Article · Mar 2014 · PLoS ONE
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    • "Radiological evaluation of lung cancer screening CT 397 cancer screening can be used as an independent predictor of cardiovascular death and events [19] [20] . For the analysis of coronary calcification, the raw data should be reconstructed into 3-mm thickness to improve interscan reproducibility and make the settings more comparable with the dedicated coronary calcium examination [21] [22] . "
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    ABSTRACT: Lung cancer is the most common cause of cancer-related death in the world. The Dutch-Belgian Randomized Lung Cancer Screening Trial (Dutch acronym: NELSON) was launched to investigate whether screening for lung cancer by low-dose multidetector computed tomography (CT) in high-risk patients will lead to a decrease in lung cancer mortality. The NELSON lung nodule management is based on nodule volumetry and volume doubling time assessment. Evaluation of CT examinations in lung cancer screening can also include assessment of coronary calcification, emphysema and airway wall thickness, biomarkers for major diseases that share risk factors with lung cancer. In this review, a practical approach to the radiological evaluation of CT lung cancer screening examinations is described.
    Full-text · Article · Sep 2013 · Cancer Imaging
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    ABSTRACT: Background: Coronary calcium score (CS), traditionally based on electrocardiography-triggered computed tomography (CT), predicts cardiovascular risk. Currently, nontriggered thoracic CT is extensively used, such as in lung cancer screening. The purpose of the study was to determine the correlation in CS between nontriggered and electrocardiography-triggered CT, and to evaluate the prognostic performance of the CS derived from nontriggered CT. Methods and results: PubMed, Embase, and Web of Knowledge were searched until November 2012. Two reviewers independently screened 2120 records to identify studies reporting the CS in nontriggered CT and extracted information. Study quality was evaluated by standardized assessment tools. Cohen κ was extracted for agreement of CS categories between nontriggered and electrocardiography-triggered CT (validation). Hazard ratio (HR) was extracted for prognostic performance. Five studies about validation comprising 1316 individuals were included. Five studies about prognosis comprising 34 028 cardiac asymptomatic individuals, mainly from lung cancer screening trials, were included. All studies were of high quality. Meta-analysis could only be performed for validation studies because studies on prognostic performance were highly heterogeneous. Pooled Cohen κ for agreement between the 2 techniques was 0.89 (95% confidence interval, 0.83-0.95) for increasing CS categories. Increasing CS categories were associated with increasing risk of cardiovascular death or events. Nontriggered CT yielded false-negative CS in 8.8% of individuals and underestimated high CS in 19.1% of individuals. Conclusions: Our analysis shows the prognostic value and potential role of nontriggered assessment of coronary calcium, but it does not suggest that electrocardiography-triggered CT should be replaced by nontriggered examinations.
    Full-text · Article · Jun 2013 · Circulation Cardiovascular Imaging
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