A percutaneous treatment algorithm for crossing coronary chronic total occlusions.

Coronary chronic total occlusions (CTOs) are frequently identified during coronary angiography and remain the most challenging lesion group to treat. Patients with CTOs are frequently left unrevascularized due to perceptions of high failure rates and technical complexity even if they have symptoms of coronary disease or ischemia. In this review, the authors describe a North American contemporary approach for percutaneous coronary interventions for CTO. Two guide catheters are placed to facilitate seamless transition between antegrade wire-based, antegrade dissection re-entry-based, and retrograde (wire or dissection re-entry) techniques, the "hybrid" interventional strategy. After dual coronary injection is performed, 4 angiographic parameters are assessed: 1) clear understanding of location of the proximal cap using angiography or intravascular ultrasonography; 2) lesion length; 3) presence of branches, as well as size and quality of the target vessel at the distal cap; and 4) suitability of collaterals for retrograde techniques. On the basis of these 4 characteristics, an initial strategy and rank order hierarchy for technical approaches is established. Radiation exposure, contrast utilization, and procedure time are monitored throughout the procedure, and thresholds are established for intraprocedural strategy conversion to maximize safety, efficiency, and effectiveness.