Usefulness of Multislice Computed Tomographic Coronary Angiography to Identify Patients With Abnormal Myocardial Perfusion Stress in Whom Diagnostic Catheterization May Be Safely Avoided

Abstract

Computed tomographic angiography (CTA) has been validated for noninvasive assessment of coronary anatomy. The aim was to establish whether CTA could guide the use of invasive coronary angiography (ICA) in symptomatic patients with intermediate risk after myocardial perfusion stress imaging (MPSI). From April 2005 to February 2006, patients referred for CTA to a cardiology practice were entered into a database. Inclusion required symptoms suggestive of coronary artery disease and intermediate-risk MPSI. Subjects with intermediate risk after MPSI underwent CTA, and if severe stenosis or moderate stenosis matching a perfusion defect was found, ICA was performed. If appropriate, patients were then sent for revascularization. Clinical follow-up was completed until December 2006. Main outcome measures were number of patients sent for ICA, immediate revascularization after ICA, and adverse outcomes (death, myocardial infarction, and late revascularization). Four hundred twenty-one patients were included. Adequate diagnostic-quality images were obtained in 99%. After MPSI-CTA assessment, 78 patients (18.5%) were sent for ICA and 343 (81.5%) were medically managed. Follow-up was 15+/-3 months. In the group referred for ICA, there were 50 cases of immediate revascularization, 1 non-ST-segment elevation myocardial infarction, 1 death, and 5 patients requiring repeat ICA, 3 of whom underwent late revascularization. In the medically managed group, 6 patients required late ICA, 1 of whom underwent revascularization. In conclusion, in symptomatic patients with suspected coronary artery disease and intermediate-risk MPSI results, CTA can identify up to 80% of patients at low risk of events in whom ICA may be safely avoided. Additional studies assessing new technologies combining MPSI-CTA are needed to refine imaging strategies in these patients.