Abstract
Percutaneous coronary intervention (PCI) for thrombotic and heavily calcified coronary artery lesions and occlusions is often hampered by difficulty in wiring the occlusions, restoring antegrade flow, and proceeding to successful stent implantation. Characterization of dynamic anatomical features such as thrombi and the calcium distribution is key to prevent periprocedural complications and long-term adverse events, which are mainly driven by stent underexpansion and malapposition and may prompt in-stent restenosis or stent thrombosis. Therefore, multimodal imaging is a critical step during PCI to better characterize these high-risk lesions and select those in which careful preparation with debulking devices is needed or to guide stent optimization with the aim of improving procedural and long-term clinical outcomes. Hence, obtaining a better understanding of the underlying cause of thrombus formation, imaging the calcium distribution, and thorough planning remain crucial steps in selecting the optimal revascularization strategy for an individual patient. In this review, we summarize current evidence about the prevalence, predictors, and clinical outcomes of "hard-rock" thrombotic lesions treated by PCI, focusing on the value of imaging and physiological assessments performed to guide interventions. Furthermore, we provide an overview of cutting-edge technologies with the aim of facilitating the use of such devices according to specific procedural features.