The Evaluation of Fractional Flow Reserve and D SPECT for the Intervention of Chronic Total Occlusion

Coronary chronic total occlusions (CTOs) are defined as an occluded coronary vessel with TIMI defined as an occluded coronary vessel with TIMI (Thrombolysis in Myocardial Infarction) grade flow 0 and an estimated duration of at least 3 months. They are frequently encountered in patients undergoing coronary angiography. The application of contemporary techniques and the use of advanced dedicated equipment lead to high procedural success and low adverse events rates in experienced centers. Fractional flow reserve (FFR) is a validated tool to assess physiological severity of coronary artery disease and have a prognostic role after percutaneous coronary intervention (PCI). SPECT (Single-Photon Emission Computed Tomography) is the golden standard for detection of myocardial ischemia. Recanalization of a CTO leads to a number of anatomical and pathophysiological changes to the coronary circulation. These include anatomical and functional collateral vessels regression and significant lumen enlargement because of recovery of blood flow and restoration of vasomotor tone. The effect of PCI on CTO is unknown. The aim of this study was to assess the functional result of CTO PCI by measuring FFR and D SPECT before and immediately post-CTO PCI and at short-term follow-up.