Background: The presence of coronary artery calcification is associated with a significant burden of coronary artery disease along with being a predictor of increased adverse ischemic events. The Diamondback 360 (R) Coronary Orbital Atherectomy System ( OAS) is a novel device designed to facilitate treatment of calcified lesions. This study aimed to evaluate the cost-effectiveness of OAS compared to standard treatment. Methods: A decision tree model utilizing ORBIT II clinical trial and Medicare data from the health system perspective was constructed. Target population was U.S. patients age >= 65 with coronary atherosclerosis due to a calcified coronary lesion, both inpatients and outpatients, and combined over a time horizon of two years for costs and lifetime for mortality. OAS was compared to standard treatment ( use of balloon angioplasty to prepare stent placement site). Outcomes were costs of index event and target vessel revascularization in two years, life years gained, and incremental cost-effectiveness ratios ( ICERs). Results: On average, OAS was projected to cost $ 1702 less than standard treatment for inpatients, $ 2360 more than standard treatment for outpatients, and $959 more than standard treatment overall; the projected mortality reduction implies 0.41 life-years gained. Compared to standard treatment, OAS was dominant in an inpatient setting, had an ICER of $ 5759 per QALY in the outpatient setting, and had an ICER of $ 2340 per QALY overall. These ICERs are below the accepted threshold for highly cost-effective interventions of $ 50,000 per QALY. Conclusions: Compared to standard treatment, OAS is likely to be cost-effective and was projected to be cost saving in an inpatient setting. Summary: A decision tree from the health system perspective was used to evaluate the cost-effectiveness of Diamondback 360 (R) Coronary Orbital Atherectomy System( OAS), a novel device designed to facilitate treatment of calcified lesions. OAS was projected to cost $ 1702 less than standard treatment for inpatients, $ 2360 more than standard treatment for outpatients, and $959 more than standard treatment overall; the projected mortality reduction implies 0.41 life-years gained. Compared to standard treatment, OAS was dominant in an inpatient setting, had an ICER of $ 5759 per QALY in the outpatient setting, and overall had an ICER of $ 2340 per QALY. (C) 2017 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/).