Long-term Outcome after Cardiac Stress Imaging

Since the 70s of the last century both myocardial perfusion imaging (MPI) using single-photon emission computed tomography and dobutamine stress echocardiography (DSE) have played an important role in the diagnosis of coronary artery disease (CAD). In the last decades, stress imaging has not only been used for diagnosing CAD, it also has emerged as a noninvasive tool providing risk stratification and prognostic information. Risk stratification is based on the concept that patients with normal stress test results could be spared invasive angiographic assessment, because a normal test result defines patients at low-risk (typically <1% per year of follow-up) for cardiac events. On the other hand, patients with abnormal stress test results are candidates for invasive coronary angiography and intervention because they have a greater risk of cardiac events. However, risk after a normal stress test result varies along with the temporal characteristics of the patients, for example the presence of known CAD. This so called warranty period is defined as the duration of time whereby the patient’s risk alters significantly from that observed during the early portion of follow-up.

This thesis focused on the long-term prognostic value of cardiac stress imaging, more precisely on DSE and SPECT MPI in patients with known or suspected CAD. The prognostic value of both imaging modalities was studied in various patient groups, which are commonly encountered in with daily practice. The studies that form this thesis can be divided in three main topics:
A) Duration of low risk after a normal cardiac exercise stress test,
B) Prediction of long-term outcome in patients considered at increased risk of adverse events,
C) Impact of early coronary revascularization on long-term outcomes.