Correlation between coronary artery calcification by non-cardiac CT and Framingham score in young patients

Abstract

Background: Previous studies have established a correlation between coronary artery calcification (CAC) measured by ECG-gated chest computed tomography (CT) and cardiovascular disease. Recent reports which included asymptomatic patients suggest that CAC measured on non-ECG gated CT is similarly associated with cardiovascular risk. This study investigates the correlation between the Framingham Risk Score (FRS) and an incidental finding of CAC on a non-gated chest CT performed for non-cardiac indications in young and seemingly healthy adults.

Methods: A cross-sectional study that included 162 CT scans performed in young patients aged 18-50 years old for non-cardiac indications in our institution was conducted. CAC score (CACS) was calculated using the Agatston method. FRS was calculated and compared to the CACS using three different approaches. The correlations between the CACS and several specific factors (i.e. age, body mass index, smoking, statins, etc.), were also evaluated.

Results: Mean age of patients was 36.43 year old and 105 (64.8%) were male. We found a significant positive correlation between the CACS and the FRS in all three approaches (p<0.05). Increased age, smoking and statin use were the only individual factors clearly associated with an increase in CACS (p = 0.002, p = 0.045 and p = 0.009, respectively).

Conclusion: This is the first report indicating that incidental CACS identified in non-gated MDCT is also associated with cardiovascular risk evaluated by FRS in a young population. Our findings suggest that young asymptomatic individuals with incidental CAC should be seriously evaluated for cardiovascular risk factors despite presumption of belonging to a low cardiovascular risk category.

Fig 1. Calcification percentage by cardiovascular risk category.

FRS = Framingham risk score.

Fig 2. Categorical distribution of coronary calcification by categorical distribution of cardiovascular risk.

Observing the proportion of the cardiovascular risk groups in the different calcification categories, it is evident that the more calcification demonstrated, the smaller the lowest cardiovascular risk group (colored in blue) becomes. p value for linear trend = 0.04. CACS = Coronary artery calcium score; FRS = Framingham risk score.

Fig 3. Calcification as a binary categorical variable by quantitative cardiovascular risk.

Box plot showing bulk of higher Framingham risk score values in the calcification group. CACS = Coronary artery calcium score; FRS = Framingham risk score.