Abstract
Coronary revascularization procedures (coronary artery bypass graft – CABG surgery, percutaneous coronary intervention – PCI) are widely used in patients with coronary artery disease (CAD). By assessing myocardial perfusion, single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) aids the diagnosis of CAD and patient risk stratification, providing useful information regarding the decision about revascularization and is well suited to assess patients after intervention. Saphenous vein graft occlusion rates range between 8% (early) and 45% (11.5 years after CABG surgery), while the 10- year occlusion rate for arterial conduits such as the internal mammary artery is about 20%. PCI restenosis rates without stenting range between 20%-65% during the first 6 months of follow-up, while coronary stenting has been shown to reduce restenosis rates of about 20%. Chest pain and exercise electrocardiography are largely unhelpful in identifying patients at risk after revascularization procedures. MPI is of proven value to assess patients post intervention. Information gained from post-intervention myocardial SPECT is crucial to differentiate patients with angina from those with exo-cardiac chest pain syndromes, to assess peri-intervention myocardial damage/acute vessel closure, to predict-detect restenosis after PCI and graft occlusion/ stenosis after CABG surgery, to detect CAD progression in non-revascularized vessels, to assess left ventricular function (gated-SPECT), to evaluate the effects of intervention if required for occupational reasons and to predict longterm prognosis. With respect to detecting graft patency, MPI has an 80-96% sensitivity and 61-88% specificity, while regarding restenosis after PCI, sensitivity and specificity range between 74-94% and 67-88%, respectively.Despite the large amount of published data demonstrating the value of myocardial perfusion SPECT imaging in patients after CABG surgery or PCI, there is still debate on whether or not these tests should be performed routinely.
Keywords: SPECT, Coronary artery bypass grafting (CABG) surgery, Percutaneous coronary intervention (PCI), Revascularization
6