Prediction of cardiovascular events by using non-vascular findings on routine chest CT

BACKGROUND: Routine computed tomography (CT) examinations contain an abundance of findings unrelated to the diagnostic question. Those with prognostic significance may contribute to early detection and treatment of disease, irrelevant findings can be ignored. We aimed to assess the association between unrequested chest CT findings in lungs, mediastinum and pleura and future cardiovascular events.

METHODS: Multi-center case-cohort study in 5 tertiary and 3 secondary care hospitals involving 10410 subjects who underwent routine chest CT for non-cardiovascular reasons. 493 cardiovascular hospitalizations or deaths were recorded during an average follow-up time of 17.8 months. 1191 patients were randomly sampled to serve as a control subcohort. Hazard ratios and annualized event rates were calculated.

RESULTS: Abnormalities in the lung (26-44%), pleura (14-15%) and mediastinum (20%) were common. Hazard ratios after adjustment for age and sex were for airway wall thickening 2.26 (1.59-3.22), ground glass opacities 2.50 (1.72-3.62), consolidations 1.97 (1.12-3.47), pleural effusions 2.77 (1.81-4.25) and lymph-nodes 2.04 (1.40-2.96). Corresponding annual event rates were 5.5%, 6.0%, 3.8%, 10.2% and 4.4%.

CONCLUSIONS: We have identified several common chest CT findings that are predictive for future risk of cardiovascular events and found that other findings have little utility for this. The added value of the non-vascular predictors to established vascular calcifications on CT remains to be determined.