Furthermore, there is robust data demonstrating prognostic information obtained from stress myocardial perfusion imaging. However, as counterintuitive and antithetical to modern practice as it seems, there are no prospective studies demonstrating that mechanical revascularization on patients with moderate or high risk perfusion scans alters prognosis. In fact, the ongoing International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial seeks to determine this very question. This study seeks to determine the regional effects of mechanical revascularization on patients with abnormal cardiac PET stress tests who were referred to angiography.