Unrequested information from routine diagnostic chest CT predicts future cardiovascular events

Abstract

Objectives: An increase in the number of CT investigations will likely result in a an increase in unrequested information. Clinical relevance of these findings is unknown. This is the first follow-up study to investigate the prognostic relevance of subclinical coronary (CAC) and aortic calcification (TAC) as contained in routine diagnostic chest CT in a clinical care population.

Methods: The follow-up of 10,410 subjects (>40 years) from a multicentre, clinical care-based cohort of patients included 240 fatal to 275 non-fatal cardiovascular disease (CVD) events (mean follow-up 17.8 months). Patients with a history of CVD were excluded. Coronary (0-12) and aortic calcification (0-8) were semi-quantitatively scored. We used Cox proportional-hazard models to compute hazard ratios to predict CVD events.

Results: CAC and TAC were significantly and independently predictive of CVD events. Compared with subjects with no calcium, the adjusted risk of a CVD event was 3.7 times higher (95% CI, 2.7-5.2) among patients with severe coronary calcification (CAC score ≥6) and 2.7 times higher (95% CI, 2.0-3.7) among patients with severe aortic calcification (TAC score ≥5).

Conclusions: Subclinical vascular calcification on CT is a strong predictor of incident CVD events in a routine clinical care population.

Fig. 1

Axial 16-slice CT images of different grades of coronary artery calcification in the left anterior descending (LAD) branch (arrows demonstrate the example area): a grade 1 (2 focal calcifications); b grade 2 (1 large calcification); c grade 3 (extensive calcification covering a large segment of the LAD branch)