Myocardial viability in coronary artery chronic total occlusion.

Coronary artery chronic total occlusion (CTO) has rapidly become a popular target of percutaneous coronary intervention (PCI). Technical and technological advances required for approaching these anatomically complex and challenging lesions have progressed at an extraordinary pace and have led to amazing success rates. Patient selection, however, has primarily focused on patient symptoms, lesion characteristics, as well as the state of collateral circulation. Multiple national and international registries have been established to follow the progress of percutaneous CTO recanalization and have provided valuable information. Concern, however, exists that this challenging procedure will become the "standard of care" before its effectiveness and appropriateness is tested in prospective controlled trials. This manuscript reviews the current state of patient selection and the need for careful assessment of the presence and extent of myocardial viability prior to lengthy, resource-intensive, and potentially high-risk procedures.