Immortality time and serial myocardial perfusion imaging: Only those who do not die may repeat the exam

Assessment of risk of future events in patients with suspected or known coronary artery disease (CAD) is challenging. Many studies are published every month on prognostic factors, and novel prognostic models and flowchart are proposed for clinical use. A quantity of data accumulated since the 70’ demonstrates the strength of stress single-photon emission-computed tomographymyocardial perfusion imaging (MPI) in predicting outcome. MPI is also commonly used as a gatekeeper to select patients for coronary revascularization. The degree of left ventricular (LV) dysfunction and the extent and magnitude of inducible myocardial ischemia are important prognostic variables that can be assessed by MPI. Transient ischemic LV cavity dilation is another high-risk variable associated with the presence of severe angiographic CAD and with an adverse outcome. Serial MPI imaging has been used to compare the effectiveness of intercurrent treatments, within the framework of randomized controlled trials. Moreover, an analysis of the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study not including patients with intervening cardiac events or revascularization found unexpected resolution of ischemia in most of these patients, potentially because of more aggressive medical treatment of cardiovascular risk factors.