Coronary Artery Calcium Score: Refining Risk stratification and Predicting Number Needed to Screen in Outpatients with Intermediate Risk Chest Pain

Objectives: Several studies have shown that coronary artery calcium scoring (CACs) is significantlyassociated with the occurrence of major cardiovascular events. We aimed to look at the feasibility ofcombining the Framingham risk Score (FRS) and CACs to refine risk stratification in outpatients withintermediate risk chest pain and adding the value of using this combination to predict the number needto screen (NNS) in those patients. Methods: We retrospectively reviewed 266 patients who underwent CCTA and CAC score and their FRS. The yield of screening for CAC was assessed by determining the NNS. Patients in this study were grouped based on FRS into very low risk (0-5), low risk(5.1-10), intermediate risk (10.1-20) and high risk (> 20) groups. Results: The mean age of our patients was 51+10.56 years; 148 (55.76 %) were men. Of 266 study patients, 52.08% had a CACs of 0.Patients with CACs >100 were significantly older and were men. Also, the prevalence of a positiveCACs for men was higher than that for women (P <0.013). Also, there was a significantly higherCACs values with body mass index >27, smoking, diabetes mellitus and hypertension according toChi square nonparametric test. The CAC scores were significantly rising as the FRS increased. UsingCCTA, the number of CAD increased as the CAC score rose and the NNS decreased significantly asthe CAC score rose. Our study revealed that 93.1% of patients with zero CAC score had no significant CAD and only 6.9 % had significant CAD (i.e. ≥70% stenosis on CCTA). Conclusion: Thestrategy of combining FRS and CAC is feasible in clinical practice to refine risk stratification in outpatients with intermediate risk chest pain. However, there is substantial heterogeneity between traditional risk and actual atherosclerosis burden. Also, our study can concluded that knowledge regardingthe NNS can lead to a more precise estimation of risk and may provide additional information of suchpatients. NNS was much higher in participants with an FRS of 0 compared with those with an FRS>10%