Utility of Per Vessel Coronary Artery Calcium (CAC) Score in Symptomatic Patients Undergoing Coronary Computed Tomography in Predicting Major Adverse Cardiovascular Events: Single Center Experience and Literature Review

Background: Atherosclerotic vascular disease remains a significant etiology of morbidity and mortality in the United States. Coronary artery calcium (CAC) is associated with increased stroke incidence and coronary atherosclerotic burden. Uncertainty remains regarding how best to interpret non-zero CAC scores, particularly in symptomatic patients.
Methods: A review of the first 1122 patients who underwent coronary CT angiography (CCTA) with CAC scoring from January 2005 until July 2012 was performed. Patients were dichotomized into 2 groups, zero CAC score and non-zero CAC score. Non-zero CAC patients were further subdivided based on the specific coronary artery containing calcium. Rates of major adverse cardiovascular events (MACE) defined as all-cause mortality, non-fatal myocardial infarction (MI), ischemic stroke, and late revascularization (>90 days following CCTA) were evaluated in each group.
Results: 505 patients (63% male, mean age 60 ± 11) with non-zero CAC scores were analyzed over a six year period with resultant median follow up period of 22 months (IQR25,75 13-34 months). Major adverse cardiovascular events were observed in 11 patients. Receiver-operator curve (ROC) analysis on each coronary segment showed significance with the presence of left main (LM) CAC (AUC 0.752, p=0.004).
Conclusions: The presence of CAC at any value in the LM in this case series appears to predispose patients to increased rates of MACE.