Risk Stratification Using Computed Tomography Coronary Angiography in Patients Undergoing Intermediate-Risk Noncardiac Surgery

Abstract

Objectives This study evaluated whether coronary artery calcium scores (CACS) and the degree of stenosis that were measured with computed tomography coronary angiography (CTCA) predicted post-operative cardiovascular events in patients who were undergoing intermediate-risk noncardiac surgery. Background Cardiovascular complications are important causes of mortality and morbidity in patients undergoing major noncardiac surgeries. Methods A total of 239 patients underwent CTCA before intermediate-risk noncardiac surgeries. We measured CACS and the degree of stenosis with CTCA and assessed clinical risk factors according to the revised cardiac risk index (RCRI) scores. Post-operative cardiovascular events were defined as cardiac death, acute coronary syndrome, pulmonary edema, ventricular arrhythmia with hemodynamic compromise, and complete heart block. Results Nineteen patients (8%) had post-operative cardiac events. The variables that correlated with the occurrence of cardiac events were RCRI (p < 0.001), CACS (p < 0.001), the presence of significant coronary artery stenosis (diameter stenosis >= 50%) (p = 0.01), and multivessel coronary artery disease (p < 0.001). In the receiver-operating characteristic (ROC) curve analysis of CACS for prediction of cardiac events, the cutoff value was 113 (sensitivity, 0.79; specificity, 0.61; area under the curve, 0.762). When comparing ROC curves of the combination models of RCRI, high CACS (>= 113), and the presence of multivessel disease, RCRI plus high CACS, RCRI plus multivessel disease, and RCRI plus high CACS plus multivessel disease were significantly more predictable of post-operative cardiovascular events than RCRI alone. Conclusions In the pre-operative risk stratification of patients who were undergoing intermediate-risk noncardiac surgeries, CTCA evaluations showed additive value to RCRI. (J Am Coll Cardiol 2013;61:661-8) (C) 2013 by the American College of Cardiology Foundation