All consecutive patients who will undergo elective PCI in native coronary arteries at the Clinica Mediterranea (Naples, Italy) will be considered for eligility. Study participants wiil require to have symptomatic ischemic heart disease attributable to critical (that is, \>70% visual estimate) stenotic lesions of native coronary arteries. Inclusion criteria in this pilot study are 1) chronic total occlusion (CTO), 2) severe target vessel calcification, and 3) severe target vessel tortuosity. CTO is defined as the presence of TIMI 0 flow within the occluded segment and angiographic or clinical evidence or high likelihood of an occlusion duration of ≥3 months. Calcification is defined severe when larger than 3x vessel diameter, and comprising the vessel wall totally in two perpendicular views. Tortuosity is defined severe when it satisfies the following criteria: one or more bends of 90° or more, or three or more bends of 45-90° proximal to the diseased segment.

200 patients will be enrolled into the study. Stents will be implanted according to current clinical practice. Techniques attempted for facilitating stent delivery in such a complex lesions are: maximize guide catheter support, optimize predilatation of the stenosis, use of a stiffer guidewire. Specific tricks include: a) buddy-wire; anchoring balloon; GuideLiner catheter. In case of severe calcification, rotational atherectomy will be electively performed with the Rotablator® system (Boston Scientific Corporation, Natick, MA, U.S.A.). Following stent implantation, postdilatation will be performed in all instances with a non-compliant balloon. All patients will receive aspirin 325 mg and clopidogrel (75 mg daily) before stent deployment, with a loading dose (600 mg of clopidogrel) given to patients not pretreated. All patients will receive 70 IU/Kg intra-arterial bolus of unfractionated heparin in order to achieve and activated clotting time \>250 seconds. Glycoprotein IIb/IIIa inhibitors will be administered according to operator preference. Estimated glomerular filtration rate (eGFR) will be calculated by applying the Levey Modification of Diet in Renal Disease (MDRD) formula. Chronic kidney disease was defined as a eGFR \<60 ml/min/1.73 m2 .

XLIMUS eluting-stent is made of cobalt chromium L 605 and the stent is available in a 6-, 8-, or 10-cell structure design (closed cell architecture). The struts thickness is 73µm. The 6-cell design is for stenting of coronary artery diameter of 2.25mm-2.50mm, 8-cell structure is used for stenting of 2.75-3.50 mm artery diameters, and the 10-cell is for larger artery diameter lesions (up to 5mm). The XLIMUS has an innovative hydrophilic-coated shaft and an extra-low tip profile (crossing profile = 0.90 mm) to access the most tortuous lesions. The highly biocompatible polylactid acid (PLLA) drug containing release matrix degrades smoothly and provides an optimal release kinetic profile. Within 30 days, about 70% of the anti-proliferative drug is distributed into the surrounding arterial tissue of the stent struts, ensuring a highly effective inhibition of smooth muscle cell migration and proliferation. Pharmacokinetic study result confirm sustained anti-proliferative drug efficacy up to 120 days.

The primary objective of the study is the assessment of the clinical performance of the XLILMUS DES, using the following criteria 1) device success, defined as the ability to insert the stent into the target lesion and the attainment of \<20% residual stenosis (by visual estimate), 2) lesion success, defined as attainment of \<20% residual stenosis of the target lesion using any percutaneous method, and 3) procedural success, defined as lesion success without any in-hospital and MACE.