OBJECTIVES: Percutaneous coronary intervention (PCI) is commonly used to treat stenosis in coronary arteries. Stenting is the standard of care, with rotational atherectomy prior to stenting used in cases with heavy calcification. Patients who undergo PCI with rotational atherectomy may have worse clinical outcomes and higher costs compared to patients with PCI alone due to heavy calcification. This novel study aims to evaluate the clinical and economic outcomes of Japanese patients who underwent PCI with or without rotational atherectomy.  METHODS: This is a retrospective cohort study using secondary data from a large Japanese hospital administrative database (EBM Provider) which covers 238 hospitals and 12.94 million patients. Patients who underwent PCI between April 2008 and December 2015 were included. Two analytical cohorts were classified: PCI alone and PCI with rotational atherectomy. Clinical and economic outcomes were compared using chi square test and t-test for categorical and continuous variables respectively. Factors that are significantly associated with each of the clinical and economic outcomes are explored in multivariate regression models (multivariate linear and logistic regression) using SAS 9.3.   RESULTS: