Chronic total occlusion (CTO) pathophysiology has been described in a few, small studies using post mortem
histology, and more recently, in vivo intravascular ultrasound (IVUS) to analyse the constituents of occluded segments.
Recent improvements in equipment and techniques have revealed new insights into physical characteristics of occluded
coronaries, which in turn enable predictable procedural success. The purpose of this review is to consider the published
evidence describing CTO pathophysiology from the perspective of the hybrid algorithm approach to CTO PCI.
Methods: Literature searches using “Chronic Occlusion”, “angioplasty”, and” pathology” as keywords. Further searches
on “coronary” “collateral”, “Viability”. Bibliographies were scrutinised for further key publications in an iterative process.
Papers describing animal models were excluded.