A coronary artery chronic total occlusion (CTO) is defined as an occlusion present for 3 or more months, which will feature classic histopathologic changes (Fig. 35-1). Although considered separately in this book, the treatment decisions for coronary revascularization should focus on coronary physiology and ischemia rather than specific anatomic considerations. To that end, the indications for treatment of CTOs should be indistinguishable from 95% coronary lesions. However, once the decision to treat a CTO percutaneously is chosen, the technical aspects of this treatment diverge significantly from standard coronary intervention. For many interventionalists, CTOs continue to represent a major technical challenge.
Histopathology of preservation of vessel architecture, including a multilayered structure in which the intima and neointima (including atherosclerotic plaque) is distinguishable from the muscularis and adventitia and, importantly, in which the external elastic lamina remains intact. This preservation of gross architecture is the pathologic feature that most enables percutaneous recanalization.
Percutaneous coronary intervention (PCI) is invariably predicated upon a steerable guide wire spanning the target lesion and acting as a rail over which devices can be delivered. Typically, this wire is tracked in the vessel lumen using angiography as a guide. In the absence of a visible lumen during angiography, tracking the coronary vessel and ensuring an intraluminal position can be difficult. Thus, the primary challenge of CTO PCI lies in initially traversing the target lesion with a guide wire. In recent years, important strategic and technical advancements have been made that facilitate overcoming this essential challenge in a reproducible fashion.1 Most major PCI programs now have, or are planning for, specialized competence in contemporary CTO procedures. An understanding of the field has become essential knowledge for all interventionalists and arguably for any cardiologist who advises patients regarding revascularization options. The goal of this chapter is to describe the technical and strategic considerations necessary to understand CTO PCI.
Angiography for CTO PCI should emphasize simultaneous dual injections to visualize the antegrade and retrograde coronary flow, thus defining the extent of the lesion. Access choice is up to the operator’s discretion recognizing that 2 arterial access points are typically required. Frequently, at least 1 of the access points is 8 Fr to facilitate specific techniques described below. The relative merits of potentially larger sheath/guide sizes via femoral access can be weighed against the reduction in vascular complications and improved patient comfort when radial access is used.2,3 When femoral access is chosen, long (45-cm) sheaths can overcome iliac tortuosity and increase guide catheter support. Guiding catheter size is usually limited to 6-Fr from the radial approach, although sheathless 7-Fr systems are increasingly common. Good passive support with coaxial alignment is crucial, especially in complex CTO procedures. Although the choice of the guiding catheter shape is generally dictated by personal experience, it is important for ...