Yield and diagnostic value of stress myocardial perfusion imaging in patients without known coronary artery disease presenting with syncope.

BACKGROUND American College of Cardiology/American Heart Association appropriate use criteria recommend performing stress myocardial perfusion imaging (MPI) for intermediate- to high-risk patients presenting with syncope but not for low-risk patients. However, there are limited data to support these recommendations. We investigated the yield of stress MPI for the evaluation of syncope in patients at risk but without known coronary artery disease. METHODS AND RESULTS Using the Cleveland Clinic Institutional Review Board-approved MPI database, we identified consecutive patients without known coronary artery disease who underwent stress MPI between 2006 and 2012 for diagnostic workup of syncope. Patients were stratified into low-, intermediate-, and high-risk groups using the Framingham risk score. For patients with abnormal MPI, left heart catheterization were reviewed if performed. There were 700 patients (mean age, 62±15 years; 55% female) who had undergone stress MPI for syncope; 659 patients (94%) had normal perfusion. Of the 41 patients with abnormal MPI, 18 had left heart catheterization (9 were false-positive); there were 23 remaining patients with abnormal MPI (16 having moderate to severe perfusion defect size) but who did not have a left-side angiogram and could have undiagnosed significant coronary artery disease. The diagnostic yield of stress MPI was similarly low among all cardiovascular risk categories. CONCLUSIONS Stress MPI for evaluation of syncope in patients without known coronary artery disease has a low-diagnostic yield among all risk categories; thus, reaffirmation and revision of the appropriateness criteria should be considered.