Abstract 13840: Stress Myocardial Perfusion Imaging Compared to Coronary Computed Tomography in Patients With Suspected Coronary Artery Disease: an International Randomized Controlled Trial

Abstract

Introduction: Functional imaging by stress myocardial perfusion imaging (MPI) and anatomical imaging by coronary computed tomographic angiography (CTA) are interchangeably used in the initial evaluation of patients with suspected coronary artery disease (CAD). Patients undergoing stress MPI as the initial study may require downstream testing less often when compared to those undergoing CTA. Methods: In this international, multicenter, open-label, randomized controlled trial, mildly symptomatic patients who had an intermediate likelihood of having CAD, and asymptomatic patients who were at intermediate risk of cardiac events, were randomized to undergo either initial stress MPI or coronary CTA. Randomization was stratified by site and symptom status. The primary outcome was downstream noninvasive or invasive testing at 6 months. The primary analysis was by intention-to-treat, after adjustment for site, symptom status and physician preference for MPI or CTA. The planned sample size was 500. Because of slow recruitment, the study was stopped at the end of 3 years, without knowledge of outcome data. (NCT01368770) Results: Between June 2011 and 2014, we recruited 303 patients (151 MPI and 152 CTA) from 6 centres in 6 countries. Average patient age was 59 years, 28% were diabetic, 80% had chest pain as the presenting symptom, and over 95% underwent the allocated study procedures. The initial test was abnormal in 29% (41/143) of patients in the MPI arm and in 56% (79/141) of the CTA arm.Fewer patients undergoing initial stress MPI had the primary outcome (adjusted OR 0.53, 95% CI 0.29 - 0.94, p=0.03). There were no important differences in the average cost per patient, or the median effective radiation dose between the strategies at 12 months. (Table) Conclusions: In the management of patients with intermediate likelihood of CAD, a strategy of initial stress MPI is substantially less likely to require further downstream testing than initial coronary CTA.