Design, rationale, and populations of an international outcomes and utilization study of pharmacologic stress SPECT myocardial perfusion imaging in contemporary practice

Abstract

A prospective, international, multicenter, observational study was conducted to investigate patient and population characteristics; utilization of radiopharmaceuticals and pharmacologic stress (PS) agents; imaging protocols; clinical outcomes; the incidence, intensity, and time to onset of adverse events; and the prognostic value of single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) procedures. The rationale, study methods, and data on presenting populations are described. Investigators recorded the demographics, American College of Cardiology/American Heart Association pretest likelihood for coronary artery disease, cardiovascular risk factors, antianginal drug use, use of PS agents and associated adverse events, and radiopharmaceutical(s) and imaging protocol for each patient enrolled. SPECT images were reconstructed at each site; investigators assigned summed stress and summed rest scores using a 17-segment model (rating perfusion on a scale ranging from 0 to 4). Patients were followed up for 1 year for clinical outcomes of revascularization, nonfatal myocardial infarction, or death. The design offers a unique opportunity to study the characteristics of patients referred for SPECT imaging over a period of time consistent with the laboratories' usual practices, provides an up-to-date PS safety registry, and allows assessment of the prognostic value of PS SPECT MPI across a wide number of covariables, as well as relationships between patient and population characteristics, SPECT MPI results, and clinical outcomes.