Orbital Atherectomy Treatment of Peripheral Artery Disease and Critical Limb Ischemia

Peripheral artery disease (PAD) is becoming extremely common worldwide, especially as risk factors and independent predictors for PAD rise to pandemic proportions. PAD affects more than 202 million people worldwide, and is prevalent in both high and low income countries.1 Approximately 18 million Americans have PAD and 2 million of these patients suffer from critical limb ischemia (CLI),2,3 the end stage of PAD.4 CLI is highly prevalent in older patients with diabetes and/or end-stage renal disease5 and is associated with high risk of amputation and mortality.6 As shown in Figure 1, the results following lower extremity amputation can be devastating — 27% of these patients will have one or more re-amputation(s) within 1 year,7 35% will have a higher level of limb loss,8 and 55% will have a contralateral limb amputation within 2-3 years.9 Furthermore, the mortality rates after primary amputation are very high, with rates ranging from 9% to 33% at 1 year7,8,10,11 and 26% to 82% at 5 years.7,10–12 Despite such devastating outcomes, primary amputation remains a common treatment modality for CLI.13 The most severe forms of PAD and CLI often involve heavily calcified lesions which may be more difficult to treat with angioplasty alone. One of the main risk factors for atherosclerotic plaque and vascular calcification is advanced age, since atherosclerotic lesions and calcium increase throughout life.14 Other risk factors include hypercholesterolemia, diabetes, hypertension, and smoking, many of which are on the rise worldwide.1,15 Historical methods of intervention, including balloon angioplasty, may be less effective for treating calcified lesions. These challenging lesions require higher inflation pressure, thus increasing the incidence of plaque rupture, embolization, and dissection.16 Orbital atherectomy (OA; Cardiovascular Systems, Inc.) is a unique device with an eccentrically mounted crown that treats peripheral lesions above-the-knee (ATK) and below-the-knee (BTK) via a dual mechanism of action (MOA): orbital sanding and pulsatile (repeated striking) forces. The orbital sanding removes intimal plaque while the repeated impact of the crown on the vessel wall (pulsatile forces) may fracture Abstract