The Augmented Value of High Coronary CT Calcium Score for Prediction of Significant CAD in Acute Chest Pain vs Stable Chest Pain

Background: Non contrast-gated scan is often performed as an initial step of Cardiac CT angiography (CCTA). This scan is used for further planning of the contrast scan and assessment of the extent of coronary calcification. Occasionally, the contrast CT scan is aborted due to heavy calcifications, and the patient is referred directly to ICA or functional study due to high chance of significant CAD. The clinical value of the imaging findings differs in different populations, e.g, acute CP (ACP) vs. stable CP patients (SCP). Therefore, our aim was to determine the predictive value of a high calcium score (CS) for significant CAD amongst patients presenting with ACP vs. SCP.

Methods: The study included patients who underwent CCTA for assessment of CAD and were found to have high CS (Agatston score >200). Patients who referred to CCTA for structural analysis and those with known previous coronary artery disease were excluded. Severe CAD was defined as >70% stenosis on CCTA/ICA. Baseline characteristics and final diagnosis of significant CAD were compared.

Results: The cohort included 220 patients, 106 with ACP and 114 with SCP. The baseline characteristics were the same except for higher smoking rate in the ACP group (42.5% vs 27.2%; p=0.017). The mean CS did not differ between the two groups (450 vs 408; P=0.371). Patients with ACP had higher severe stenosis rate (60.4% vs 36.8%; p<0.001), underwent more PCI (50% vs 24.6%; p<0.001) and underwent more CABG (9.4% vs 2.6%; p=0.033). In multivariable analysis ACP was independently associated with higher rates of severe coronary artery stenosis (OR=2.60 95% CI [1.47-4.62]; p=0.001).

Conclusion: High CS value is predictive of severe CAD in patients presenting with ACP but not in patients with SCP. Our findings suggest that the initial CS value should impact the decision of weather to proceed with the CT contrast scan or refer to ICA, in patients with ACP.