Abstract 587: Absence of Coronary Calcium on Non-contrast Enhanced, Non ECG-gated CT Correlates with Non-obstructive Coronary Artery Disease. A Retrospective Data Analysis of Liver Transplant Recipients

Background: Coronary angiography (CAG) remains the gold standard to diagnose coronary artery disease (CAD). However, it is associated with multiple risks and its utility is not well defined in the liver transplant population. Alternatives to evaluate for CAD such as coronary artery calcium score (CACS) are being increasingly investigated. Hypothesis: To determine if the absence of coronary arterial calcium (CACS=0) on non-contrast, non-ECG gated chest CT scan can exclude obstructive CAD in liver transplant patients. Methods: We performed a retrospective analysis of data collected from liver transplant recipients. We included patients who had a CT chest without contrast and CAG less than one year apart. Agatston score was derived from non-IV contrast, non-ECG gated chest CT’s utilizing the syngo.via platform (Siemens Healthcare). CACS was compared against CAG. Patients with coronary stents were excluded. We determined NPV, PPV, sensitivity and specificity of using CACS = 0 as predictor of the absence of obstructive CAD. Results: Mean age at date of transplant was 59.03 and males accounted for 68.8% of our population. The negative predictive value for CACS=0 as a predictor of non-obstructive CAD was 100%. Positive predictive value for CACS≥1 was 6.8%. Sensitivity and specificity for the correlation between CACS and CAD were 100% and 33% respectively (Figure 1). CACS was stratified into four subgroups based severity, and we found that all patients with obstructive CAD had scores >400 (Figure 2). Conclusion: The absence of coronary arterial calcium (CACS=0) on non-contrast, non ECG gated chest CT has a high negative predictive value and can exclude the presence of obstructive CAD.