Inclusion Criteria:  Angiographic inclusion criteria  Severely calcified stenoses Vessels with RVD between 2.5 - 4.0 mm TIMI flow 3  Exclusion Criteria:  Angiographic exclusion criteria  Concomitant use of rotational atherectomy Severe vessel tortuosity Stenosis un-crossable with a balloon/guidewire Concomitant conditions Contraindication for adenosine administration. Hemodynamic or electrical instability. Active liver disease or hepatic dysfunction, defined as AST or ALT > 3 times the ULN. Severe renal dysfunction, defined as an eGFR <30 mL/min/1.73 m2, unless the patient is in renal support therapy.  Other exclusion criteria  Unable to provide written informed consent (IC) Known pregnancy or breast-feeding at time of inclusion; pre-menopausal women, unless sterilized, must take an effective method of birth control up to 15 weeks after the end of treatment with IP Prior myocardial infarction subtended to the PCI target vessel. Akinesia or dyskinesia in myocardial segments in the distribution area of the PCI target vessel. Severe systolic dysfunction defined as left ventricular ejection fraction < 35%. Patent arterial or venous surgical graft supplying the PCI target vessel. Previous TIMI flow < 1 before guidewire crossing. Patient not eligible for drug-eluting stent treatment.