Significance of Coronary Artery Calcium Found on Non–Electrocardiogram-Gated Computed Tomography During Preoperative Evaluation for Liver Transplant

Abstract

Guidelines to evaluate patients for coronary artery disease (CAD) during preoperative evaluation for orthotopic liver transplantation (OLT) are conflicting. Cardiac catheterization is not without risk in patients with end-stage liver disease. No study to date has looked at the utility of non-electrocardiogram-gated chest computed tomography (CT) in the preliver transplant population. Our hypothesis was that coronary artery calcium scores (CACSs) from chest CT scans ordered during the liver transplant workup can identify patients who would benefit from invasive angiography. Nine hundred and fifty-three patients who underwent coronary angiography as part of their OLT workup were considered. Charts were randomly selected and reviewed for the presence of a chest CT performed before coronary angiography during the OLT workup. Agatston and Weston scores were calculated. CACS results were compared with coronary angiography findings. Nine of 54 patients were found to have obstructive CAD by angiography. Receiver-operating characteristic analysis demonstrated that an Agatston score of 251 and a Weston score of 6 maximized sensitivity and specificity for detection of obstructive coronary disease. An Agatston score <4 or Weston score <2 excluded the presence of obstructive CAD; using these thresholds, 13 patients (24%) or 15 patients (28%), respectively, could have theoretically avoided catheterization without missing significant CAD. In conclusion, our data identify the strength of CACS in ruling out coronary disease in patients being evaluated for OLT. Calcium scoring from non-electrocardiogram-gated CT studies may be integrated into preoperative algorithms to rule out obstructive CAD and help avoid invasive angiography in this high-risk population.