More complex atherosclerotic plaques containing calcium present additional challenges for interventional R428 procedures. The deposition of calcium within
these lesions reduces vessel elasticity and may create eccentric expansion during balloon angioplasty. This typically leads to increased perforation and/or dissection rates in this population . Rotational atherectomy has been employed to treat patients with coronary arterial calcific disease by enlarging the vessel lumen. The mechanism of action, which uses a rotating, diamond-coated burr within the vessel has been shown to have potential utility to prepare calcified lesions for further treatment that will be used to prevent restenosis (e.g., stent) . A recent study by Brogan et al.  highlighted the benefits of debulking
when treating patients with calcified coronary arteries. Using quantitative angiographic methods, they demonstrated the beneficial effects of calcium plaque reduction using rotational atherectomy. These benefits include increase in acute luminal gain, decreased vessel stretch and less elastic recoil resulting in procedural success in 37 of 41 patients (90%). Moussa et al.  treated 75 consecutive patients (106 lesions) with rotational atherectomy prior to coronary stenting and reported procedural success in 93.4% of lesions. In spite of these successes, other reports suggest that distal embolization of atherectomy fragments may result in no-reflow or slow flow, which can result Crizotinib chemical structure in serious complications such as adverse ischemic and clinical events including but not limited to microvascular spasm, MI and no-reflow . The OAS has additional advantages over other atherectomy devices. The average particle size created by rotational atherectomy is 5–10 μm
 vs. particles averaging less than 2 μm when the OAS is used . Particles ablated from the occluding plaque by the OAS are removed through the reticuloendothelial system. In addition, the orbit of the OAS crown can be regulated via the crown’s rotational speed, to achieve optimal plaque modification. This ability to treat the lesion with a single device may allow GBA3 for significant cost savings to be realized. Perforation rates of 0 to 1.5% have been reported with high-speed rotational atherectomy and differ based on technique . In this single-center subset of ORBIT I trial patients, two minor dissections, one major dissection and two perforations occurred. Use of smaller crown sizes and improved technique is expected to reduce acute complications in the future. In comparison, the OAS used in this study did not cause slow flow or distal embolization. This may be due to the mechanism of action. The elliptical orbit allows blood and micro-debris to flow past the crown, thus continually dispersing the particulate, cooling the crown and reducing the risk of thermal injury to the target vessel.