FAPI Imaging Assessment of Chronic Total Occlusion

This registry will include consecutive patients presenting with at least one chronic total coronary occlusion (CTO) identified via coronary angiography or cardiac computed tomography angiography (CCTA) at our center. Due to the complexity of CTO lesions, both procedural success rates and prognosis improvements are limited. The progression and development of atherosclerotic plaques involve fibroblast activity, contributing to the formation of fibrous caps and calcified nodules through various mechanisms. Myocardial fibrosis within chronically occluded segments is strongly linked to ventricular remodeling and patient prognosis. The activation of cardiac fibroblasts (CFs) is a critical early phase in myocardial fibrosis, playing a key role in fibrotic progression. However, the role of activated CFs in CTO patients has remained unclear, mainly due to the lack of reliable in vivo assessment techniques for detecting CF activation. Recent studies have demonstrated that radionuclide-labeled fibroblast activation protein inhibitor (FAPI) imaging is an effective and reliable technique for detecting both myocardial fibrosis and activated CFs in arterial plaques. Preliminary data suggest that FAPI imaging can characterize plaque composition and assess the extent of myocardial fibrosis in various cardiovascular conditions. However, its potential to predict the ease of CTO recanalization and subsequent clinical outcomes remains to be fully explored. The aim of this prospective cohort study is to evaluate the predictive value of FAPI imaging in patients with at least one untreated CTO. All enrolled patients will undergo baseline assessments prior to intervention, including blood tests, clinical evaluations, and imaging studies. These imaging studies will include myocardial FDG/perfusion imaging, FAPI imaging, and resting perfusion imaging. In selected patients, additional evaluations such as stress myocardial perfusion imaging, magnetic resonance imaging (MRI), and echocardiogra