Does prior coronary artery bypass grafting affect percutaneous chronic total occlusion revascularization?

Abstract

Chronic totally occluded coronary arteries are commonly encountered and often referred to as the “final frontier of interventional cardiology” [1]. Despite recent advances in wires, catheters, devices and techniques, this lesion subset remains the most technically challenging in the current era of interventional cardiology. Prior coronary artery bypass graft (CABG) surgery further increases the complexity of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and many of these special considerations are highlighted in this article. CTOs are commonly discovered among patients referred for coronary angiography. In a large Canadian catheterization registry 18% of patients were found to have at least one CTO [2]. While CTOs are common among all patients referred for angiography, those with prior CABG represent a population with very high CTO prevalence. Approximately half of post-CABG patients undergoing coronary angiography have an unrevascularized CTO [2]. Among CTOs identified during coronary angiography, PCI is attempted in only 10–13%, and the CTOs successfully revascularized by PCI are a mere 7% [2,3]. In the SYNTAX trial, successful revascularization was achieved in only 49.4% of CTOs in the PCI cohort and 68.1% of CTOs in the surgical cohort on a per-lesion basis [4]. This observation suggests that CTO revascularization remains a challenge not only for interventionalists, but also for surgeons. However, the presence of a CTO, particularly in the setting of multivessel disease remains one of the strongest predictors of referral for CABG [3]. While the patency of the left internal mammary artery is over 90% at 10 years post-CABG, the per-patient incidence of 1-year saphenous vein graft (SVG) failure (defined as stenosis