Visually scored calcifications in thoracic arteries predict death: follow-up study after lung cancer CT screening

Our plain-English summary of Visually scored calcifications in thoracic arteries predict death: follow-up study after lung cancer CT screening, by T. Vehmas (Acta Radiologica, 2012).

The study

• Author: T. Vehmas
• Journal: Acta Radiologica
• Published: 2012;53(6):643-7
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Coronary arterial calcification scoring with special cardiac algorithms predicts death. However, a large number of patients undergo a non-cardiac chest CT for other reasons and the information on such arterial calcifications has so far received little attention.

Purpose: To explore whether visually detected chest atherosclerotic calcifications, which are unrelated to the indication of chest CT, predict mortality.

Material And Methods: A total of 504 men (aged 39-81 years, mean 63 years) were previously screened for lung cancer with spiral CT and later visually scored for atherosclerotic calcifications in the aorta and the origin of its great branches, and in coronary arteries. Their mortality was later checked in the national register, at a mean follow-up time of 10.4 years. Cox regression was used, adjusted for age, BMI, smoked pack-years, and asbestos exposure.

Results: One hundred and sixty deaths occurred during the follow-up, of which 57 were from cardiovascular disease. Calcifications at several sites significantly predicted all-cause and cardiovascular deaths in the enter models. In the backward model, calcifications in the aortic arch (hazard ratio HR = 1.35, 95% confidence interval 1.08-1.69, P = 0.009) and in the brachiocephalic origin (HR = 1.45, 1.15-1.82, P = 0.002) remained independent predictors of all-cause deaths. As regards cardiovascular deaths, calcifications in the left anterior descending artery (HR = 1.86, 1.29-2.67, P = 0.001) and brachiocephalic calcifications (HR = 1.65, 1.09-2.49, P = 0.018) remained independent predictors in the backward models.

Conclusion: Incidental arterial calcifications in routine chest CT should be actively reported to aid the recognition, preventive measures and medication of early atherosclerosis. The value of interventions after finding such calcifications should be further studied.

In plain English

This study followed 504 men, asbestos-exposed construction workers near Helsinki, Finland, who had lung cancer screening chest CT scans in 1996–1997. A radiologist had visually scored artery calcifications from 0 to 3 in the coronary arteries, the aorta and the origins of its main branches. Deaths were traced in the national register over a mean of 10.4 years. There were 160 deaths, 57 of them from cardiovascular disease. After adjusting for age, body mass index, smoking and years of asbestos exposure, calcifications at several sites significantly predicted death. In the final models, two sites predicted death from any cause: aortic arch calcification (hazard ratio 1.35 per score unit, 95% confidence interval 1.08–1.69) and calcification at the origin of the brachiocephalic artery (1.45, 1.15–1.82). Two sites predicted cardiovascular death: left anterior descending coronary artery calcification (1.86, 1.29–2.67) and brachiocephalic calcification (1.65, 1.09–2.49). No significant association was found with deaths from cerebrovascular disease. The author concluded that incidental calcifications on routine chest CT should be actively reported, and that the value of acting on them needs further study.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective cohort (follow-up) study using CT images from an earlier lung cancer screening study, linked to national death register data
• Who was studied: 504 male asbestos-exposed construction workers living in or near Helsinki, Finland, screened for lung cancer with CT in 1996–1997. Inclusion required either an asbestosis diagnosis, or smoking (printed as '10 pack-years') together with bilateral pleural plaques. Mean age was 63 years (range 39–81). Deaths were followed to April 2009.
• Exposure: The main exposure studied was visually scored atherosclerotic calcification, graded 0–3 per artery on single-slice spiral chest CT. Sites scored were the coronary arteries (RCA, LAD, LCX), the ascending, arch and descending aorta, and the origins of the brachiocephalic, left carotid and left subclavian arteries. Asbestos exposure (mean duration 26.3 years, range 2.0–48.0; fiber type not stated) was used as an adjustment factor, along with age, BMI and smoked pack-years.
• Main results:
  • Mean follow-up was 10.4 years (range 0.25–13.0 years), totaling 5251 person-years.
  • Of the 504 workers, 160 died (31.7%). 57 deaths were from cardiovascular disease: 33 from ischemic heart disease, 16 from cerebrovascular disease and 8 from other cardiovascular causes.
  • In adjusted models testing each score separately, the following significantly predicted all-cause death: LAD calcification, the coronary sum score, calcification of the ascending aorta, aortic arch and descending aorta and the aortic sum, calcification at the brachiocephalic and left subclavian origins and their sum, and the grand sum. For example, brachiocephalic calcification had a hazard ratio of 1.58 per score unit (95% CI 1.27–1.97).
  • In the backward-elimination model for all-cause death, two calcification sites remained significant predictors: the aortic arch (HR 1.35, 95% CI 1.08–1.69, P 0.009) and the brachiocephalic origin (HR 1.45, 1.15–1.82, P 0.002).
  • In the separate adjusted models for cardiovascular death, LAD calcification had a hazard ratio of 1.98 per score unit (95% CI 1.38–2.83).
  • In the backward-elimination model for cardiovascular death, two calcification sites remained significant predictors: LAD calcification (HR 1.86, 1.29–2.67, P 0.001) and brachiocephalic calcification (HR 1.65, 1.09–2.49, P 0.018).
  • No significant association was found between calcifications and deaths from cerebrovascular disease. Results for ischemic heart disease deaths were described as very similar to those for cardiovascular deaths but with less statistical power; the data were not shown.
  • Mean years of asbestos exposure did not differ significantly between those who died and those who survived (27 vs 26 years, P 0.165). The author stated that asbestos exposure had not previously been proven to be a risk factor and that this study supported this, so occupational asbestos exposure did not prevent generalizing the results.
• The authors' conclusion: The author concluded that incidental arterial calcifications seen on routine chest CT should be actively reported, to help recognize, prevent and treat early atherosclerosis, and that the value of interventions after finding such calcifications should be studied further.
• Limitations the authors state:
  • The cohort was limited to blue-collar male workers, most of them former or current smokers and mostly overweight.
  • More detailed lifestyle information was not available.
  • The single-slice CT method is now largely outdated. The author suggested that modern CT might show a stronger association, so the risk found may be an underestimate.
  • A few of the most recent deaths may have been missed by the register search; the author judged this unlikely to affect the overall results.
  • The lack of a finding for cerebrovascular deaths was attributed to the small number of such deaths and lack of statistical power.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Asbestos Exposure, Hazard Ratio, confidence interval.

Related studies

• Lung and pleural CT signs predict deaths: 10-year follow-up after lung cancer screening of asbestos-exposed workers — T. Vehmas, P. Oksa, et al. (2012)
• Lung function predicts mortality: 10-year follow-up after lung cancer screening among asbestos-exposed workers — T. Vehmas, P. Pallasaho, et al. (2013)
• Atherosclerotic and pleural calcifications are related among asbestos-exposed workers — T. Vehmas, A. Hiltunen, et al. (2008)
• Chest HRCT signs predict deaths in long-term follow-up among asbestos exposed workers — T. Vehmas, P. Oksa (2014)
• The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements — G.E. Goodman, M.D. Thornquist, et al. (2004)
• Diffuse Malignant Peritoneal Mesothelioma Presenting with Psammomatous Calcification on a Cervical Smear — A. Tan, P. Cohen, et al. (2015)

Browse return to medical research.