OBJECTIVES: Percutaneous treatment of severely calcified coronary artery lesions is associated with lower procedural success and higher complication rates compared to non-calcified lesions. Compared to rotational atherectomy (RA), orbital atherectomy (OA) has been shown to decrease procedure failure and reintervention rates. Our objective was to explore the cost-effectiveness of OA compared to RA in the Japanese healthcare system. METHODS: A decision-analytic model calculated reintervention rates and consequent total one-year costs. Effectiveness inputs were therapy-specific target lesion revascularization (TLR) rates and all-cause mortality, pooled from clinical studies. Index and reintervention costs were determined based on claims data analysis of n=33,628 subjects treated in the period 2014-2016. We computed incremental cost-effectiveness in Japanese Yen (JPY) per life year (LY) gained based on differences in one-year cost and projected long-term survival. In the absence of a final reimbursement amount, we tested OA device costs between JPY 350,000 and JPY 550,000.   RESULTS: OA was found to be associated with improved clinical outcomes (twelve-month TLR rate 5.0 vs. 15.7%) and projected survival gain (8.34 vs. 8.16 LYs (+0.17), based on one-year mortality of 5.5 vs. 6.8%). Total one-year costs were lower for device cost of 430,000 JPY or less, and reached a maximum ICER of JPY 753,445 per LY at highest assumed device cost, making OA dominant or cost-effective across the tested range. Findings were robust across a wide range of clinical, utilization, and cost assumptions.Orbital atherectomy for the treatment of severely calcified coronary artery lesions is a cost-effective and potentially cost-saving treatment approach in the Japanese healthcare system. CONCLUSIONS: Orbital atherectomy for the treatment of severely calcified coronary artery lesions is a cost-effective and potentially cost-saving treatment approach in the Japanese healthcare system. Future confirmatory analyses are warranted.