Aorto-ostial lesions (AOL), located at the origin of the right and left coronary arteries and surgical bypass grafts, are of critical clinical importance. These lesions compromise blood supply to large myocardial territories and can cause extensive myocardial ischemia. The purpose of this chapter is to review unique lesion, anatomic, and procedural characteristics that contribute to these challenges and to address novel approaches designed to facilitate the treatment of these lesions.
Flow-limiting AOLs are defined as stenoses located within 3 mm of the origin of the native coronary arteries and of surgical bypass grafts.1 The challenge of percutaneous coronary interventions (PCI) in AOL is derived from their anatomic location and variable relationship with the aorta. Percutaneous interventions in AOL may result in inferior procedural and clinical outcomes compared to interventions in non-AOL coronary lesions.2 Optimal outcome requires complete stent expansion and apposition to the vessel wall, complete lesion coverage with the stent, and accurate localization of the proximal stent edge within a virtual aorto-ostial landing zone (AOLZ)3 (Figure 19A-1). Inferior outcomes may be due to inaccurate stent deployment (geographic miss) as well as to unique anatomic and histologic characteristics of AOL that may increase the risk of restenosis and stent thrombosis. Factors that challenge optimal AOL stenting are summarized in Table 19A-1.
The aorto-ostial landing zone (AOLZ), defined as the area along the axis of the coronary artery located within 1 mm of the aorto-ostial plane. (Reproduced with permission from the International Journal of Cardiology.)
Table 19A-1Factors Associated With Suboptimal Stenting of Aorto-Ostial Coronary Lesions (AOL) ||Download (.pdf) Table 19A-1 Factors Associated With Suboptimal Stenting of Aorto-Ostial Coronary Lesions (AOL)
|Factor ||Description |
|AOL anatomy ||Three-dimensional funnel-shaped (Figure 19A-3A) |
| ||Variable angulation of coronary artery relative to the aortic wall (Figure 19A-3B) |
|AOL histology ||Frequent severe calcification (Figure 19A-4) |
|Stent design ||Tubular stent (Figure 19A-3) |
|Suboptimal angiographic imaging ||Dye injection in aorta proximal to AOL or within the vessel distal to AOL |
|Guide catheter positioning ||Unstable position of guide catheter positioned in aorta proximal to AOL |
|Stent positioning ||Unstable position of undeployed stent due to guide catheter instability |
The origin of the native coronary arteries from the aorta has a unique 3-dimensional funnel-shaped anatomy, transitioning to a tubular geometry further downstream4 (Figure 19A-2). Additionally, the coronary arteries may have variable vertical and horizontal takeoff angles relative to the plane of the aortic wall. Coronary stents have a cylindrical design, and apposition to the wall of the funnel-shaped ostium may not be achieved (Figure 19A-3A). An acutely angulated takeoff angle of the coronary arteries relative to the aortic wall makes it challenging to deploy the ...