• The minimal luminal diameter (MLD) at 8-month follow-up of the coronary segment treated with stent implantation in CTO lesions. The treated segment is defined as the segment covered by the stent(s) plus 5 mm proximally and distally to the stent(s).
  

• - Major adverse cardiac events (MACE) rate at 30 days, 8, 12 and 24 months;
  
• - In-segment late loss (LL) at 8 months;
  
• - Binary restenosis rate in the treated coronary segment, defined as the rate of patients showing an in-segment diameter stenosis greater than 50% at 8 months;
  
• - In-segment total re-occlusion at 8 months;
  
• - Target Lesion Revascularization (TLR) at 8 ,12 and 24 months;
  
• - Target Vessel Revascularization (TVR) at 8 ,12 and 24 months;
  
• - Angiographic success defined as achievement of a final residual diameter stenosis of < 30 % (by QCA)using the assigned study stent;
  
• - Procedural success defined as angiographic success, without the occurrence of death, myocardial infarction (MI), or repeat revascularization of the target lesion during the hospital stay;
  
• - Sub acute stent thrombosis defined as angiographic documentation <30 days after the index procedure (site-reported or by QCA) of thrombus or total occlusion at the target site and freedom from an interim revascularization of the target vessel;
  
• - Late stent thrombosis defined as angiographic documentation >30 days after the index procedure (site-reported or by QCA) of thrombus or total occlusion at the target site and freedom from an interim revascularization of the target vessel.
  

This is a multicenter, prospective, randomized study that will be conducted at up to 22 centers in Italy. All patients who meet the eligibility criteria will be randomized to Cypher Select-TM Stent or SONIC-TM Stent. Patients will have repeat angiography at 8 months and clinical follow-up to 2 years. The study population will consist of 200 patients with single chronic total occlusion in a native coronary artery with a reference diameter between 2.75 mm and 3.75 mm. The occlusion has to be dilatable by balloon angioplasty and can be fully covered by < 2 stents of ≤33 mm of length each. The CTO is defined as obstruction of a native coronary artery, at least 30 days old, with no luminal continuity and with Thrombolysis in Myocardial Infarction (TIMI) flow grade 0 or 1. Following confirmation of eligibility criteria and successful pre-dilating of the CTO, patients will be randomized in a 1:1 ratio to receive SES CYPHER SELECT Stent or BMS SONIC Stent. The coronary angiograms will be assessed at a core laboratory with Quantitative Coronary Angiography. Quantitative angiographic parameters including minimal luminal diameter, binary restenosis rate, total reocclusion rate, late luminal loss, will be evaluated at 8 months. The incidence of clinical events, including death, myocardial infarction, target vessel revascularization, stent thrombosis, will be evaluated at 8, 12 and 24 months.