Coronary chronic total occlusions

In contrast with nonocclusive coronary lesions, chronic total occlusions (CTO) represent the most challenging lesion subset for percutaneous coronary intervention (PCI). Although no single definition is perfect for all therapies and situations, using uniform consensus definitions across studies provides greater consistency, is more informative than using varying ad hoc definitions, and can provide insights into comparative health outcomes. Clinical trial design for CTO therapies can be particularly challenging. CTO-ARC thus not only has provided uniform definitions for end points specific to CTO interventions but also recommends a consensus framework for the design of clinical trials and registries, including the procedural data collected during CTO-PCI.

Note: paragraph extracted from CTO-ARC, available through the link below.