Coronary Flow Reserve Following Orbital Atherectomy

Subjects must meet all inclusion criteria and no exclusion criteria to be eligible to participate in the study. Inclusion Criteria 1. Subjects must be at least 18 years of age. 2. Subjects must be scheduled for percutaneous coronary intervention involving stent deployment in de novo coronary lesions. 3. The target vessel must be a de-novo coronary artery with a severely calcified lesion. 4. The target vessel reference diameter must be ≥ 2.0mm and ≤ 4.0 mm. 5. The lesion length must not exceed 40 mm. 6. The target vessel must have a thrombolysis in myocardial infarction (TIMI) flow 3 at baseline. 7. The target lesion must have fluoroscopic, intravascular ultrasound (IVUS) or optical coherence tomograph (OCT) evidence of severe calcium deposit at the lesion site based on the protocol definition. 8. The lesion must be crossable with the ViperWire Advance® coronary guide wire. 9. Successful revascularization using OAS and stent deployment as demonstrated by no evidence of stent dissection and no more than 50% stenosis proximal to the stent. Exclusion Criteria 1. Inability to understand the study or a history of non-compliance with medical advice. 2. Unwilling or unable to sign the informed consent form (ICF). 3. History of any cognitive or mental health status that would interfere with study participation. 4. Currently enrolled in any pre-approval investigational study. Note: This does not apply to long-term post-market studies unless these studies might clinically interfere with the current study endpoints. 5. Female subjects who are pregnant or planning to become pregnant within the study period. 6. Previous myocardial infarction of the target vessel. 7. Known sensitivity to contrast media, which cannot be adequately pre-medicated. 8. Diagnosed with chronic renal failure or has a serum creatinine level \> 2.5 mg/dl. 9. History of a stroke or transient ischemic attack (TIA) within six (6) months of the procedure. 10. Active peptic ulcer or upper gastrointestinal (GI) bleeding within six (6) months of the procedure. 11. Wall motion abnormality in the intended vessel target zone. 12. Severe chronic obstructive pulmonary disease (COPD), asthma or current use of the medication: aminophylline. 13. 2nd or 3rd degree atrioventricular (AV) block. 14. Evidence of current left ventricular ejection fraction (LVEF) ≤45% (where current is defined as the latest LVEF measurement completed within the last 6 months). 15. New York Heart Association (NYHA) class III or IV heart failure. 16. Previous coronary artery bypass surgery. 17. Known allergy to atherectomy lubricant components such as soybean oil, egg yolk phospholipids, glycerin and sodium hydroxide. 18. Severe aortic stenosis. 19. Severe left ventricular hypertrophy. 20. Subject with angiographically confirmed evidence of more than 1 lesion requiring intervention. 21. Target vessel has other lesions with greater than 50% diameter stenosis based on visual estimate or on-line quantitative coronary analysis (QCA). 22. Target vessel has angiographically visible or suspected thrombus. 23. Target vessel has a stent from previous PCI unless: 1. The stent was implanted greater than 30 days prior to the treatment, and 2. The stent has no higher than 30% in-stent stenosis, and 3. The stent is on a different branch than the target lesion. 24. Target vessel is excessively tortuous. 25. Target lesion is an ostial location (within 5 mm of ostium) or an unprotected left main lesion. 26. Target lesion is a bifurcation. 27. Target lesion has a ≥ 1.5 mm side branch. 28. Angiographic evidence of a dissection prior to initiation of orbital atherectomy device (OAD). 29. Angiographic evidence of MACE during procedure.