Rationale and design of a randomized controlled trial comparing stress myocardial perfusion imaging with coronary CT angiography as the initial imaging study for intermediate-risk patients admitted with chest pain.

BACKGROUND: Noninvasive cardiac imaging plays an important role in the diagnosis and management of coronary artery disease (CAD). Prior studies have focused on the diagnostic performance of noninvasive modalities using angiographically significant stenoses as the reference standard. Recent trends in evidence-based medicine and increasing imaging utilization call for validation of diagnostic algorithms with well-designed, controlled trials with clinical outcome endpoints.

OBJECTIVE: To compare the performance of stress radionuclide myocardial perfusion imaging (MPI) and coronary computed tomography angiography (CTA) in terms of outcomes.

METHODS: We designed a single-center, randomized controlled trial that compares MPI and CTA as the initial modality for the evaluation of patients hospitalized for chest pain without known CAD or acute myocardial infarction. Patients with intermediate-risk characteristics and a clinical need for noninvasive imaging are included. The primary outcome measured is the incidence of conventional angiography not leading to subsequent coronary revascularization within 1 year. The study is powered to detect a reduction from 11% to 3% in catheterization not leading to an intervention with a sample size of 400. Secondary outcomes include procedural complications and posttest renal dysfunction (safety outcomes), major adverse cardiovascular events, length of hospital stay, subsequent hospitalizations and imaging, changes in medical management, and tolerability of the noninvasive test.

CONCLUSIONS: The results of this trial will further our understanding of the relative appropriateness of CTA and MPI in evaluating intermediate-risk patients hospitalized with chest pain. It will also have implications for the design and probability of success of multicentered trials that are currently being planned.