Orbital atherectomy treatment of severely calcified native coronary lesions in patients with prior coronary artery bypass grafting: Acute and one-year outcomes from the ORBIT II trial.

AIMS: Patients undergoing percutaneous coronary intervention (PCI), with a history of coronary artery bypass grafting (CABG), may be at increased risk for mortality and repeat revascularization, compared with patients without prior CABG. In this post-hoc analysis of the ORBIT II trial, safety and efficacy of coronary orbital atherectomy (OA) to modify severe coronary artery calcium, prior to stent placement, was evaluated in subjects based on history of CABG.

METHODS AND RESULTS: Comorbidities: diabetes, dyslipidemia, hypertension, and history of myocardial infarction (MI) were more prevalent in the CABG group. The in-hospital major adverse cardiac event (MACE) rate, defined as a composite of cardiac death, MI (CK-MB>3× ULN), and target vessel revascularization (TVR), was higher in the CABG group (16.9% vs. 8.5%, p=0.04), driven primarily by a higher incidence of MI (16.9% vs. 8.0%, p=0.03); however, Q-wave rates were low at 1.5% vs 0.5%, (p=0.38). There was no significant difference in rates of cardiac death (6.2% vs. 2.7%, p=0.17) and TVR (7.9% vs. 5.5%, p=0.47).

CONCLUSIONS: Low rates of TVR, cardiac death, and Q-wave MI, suggest OA treatment to facilitate stent delivery is successful and provides durable outcomes in subjects with and without prior CABG.

CONDENSED ABSTRACT: Patients with history of CABG have extensive coronary artery disease. Those who undergo PCI may be at increased risk for mortality and repeat revascularization, compared with patients without prior CABG. This post-hoc analysis of ORBIT II trial evaluated safety and efficacy of coronary OA to modify severe coronary artery calcium, prior to stent placement, based on subject history of CABG. The MACE rate was higher in the CABG group, driven by higher incidence of MI; however, Q-wave rates were low. OA treatment to facilitate stent delivery is successful, but higher incidence of non-Q-wave MI in CABG patients warrants further study.