This is a prospective, randomised study to compare the endothelial dysfunction of BMS vs SES, both implanted in the same patient with multiple de novo coronary artery lesions undergoing elective PCI. The primary end point will be the evaluation of endothelial dysfunction at 6 months follow-up by measuring the change in vessel diameter in 5 points of the stent and peri-stent site after infusion of acetylcholine.

This prospective, randomised study compares the endothelial dysfunction of BMS vs SES, both implanted in the same patient with multiple de novo coronary artery lesions undergoing elective PCI. From february 2009 to may 2009 we aim to enroll 20 patients with at least two de novo significant angiographic stenoses in different coronary segments who will have similar diameter and length. The primary end point will be the evaluation of endothelial dysfunction at 6 months follow-up by measuring the change in vessel diameter in 5 points of the stent and peri-stent site after infusion of acetylcholine.

Inclusion Criteria:

• stable angina pectoris
• at least two significant angiographic stenoses in different native coronary vessels or in the same vessel but two different ramifications with similar diameter
• non-surgical patients

Exclusion Criteria:

• acute coronary syndromes
• myocardial infarction within 3 months from event
• clinical or angiographic coronary vasospasm
• coronary angiographic findings of a fresh thrombus in the initial angiography (filling defect proximal to or involving the stenosis)
• coronary anatomy unsuitable for for intracoronary acetylcholine testing (left main coronary artery disease >30%, surgical three vessel disease or other anatomical considerations that make it unsafe to perform intracoronary studies)
• progression of lesions or development of de novo lesions in nontarget lesions or vessels on follow-up angiography
• patients with a vessel diameter < 2,50 mm and length lesions <10 and >30 mm.
• patients with vessel diameter difference (SES vs BMS) >0,5mm and length difference of the stenosis >50%
• lesions treated with balloon injury <10 mm or >50 mm in length
• severe left ventricular (LV) systolic dysfunction
• bifurcation/ostial
• presence of an unhealed dissection identified by intravascular ultrasound (IVUS) performed at the end of the study.
• angiographic restenosis in follow-up angiography
• patients with severe risk factors for endothelial dysfunction: severe renal failure, life expectancy less than 1 year, uncontrolled diabetes, uncontrolled hypertension (systolic blood pressure >180mmHg), currently smoking, uncontrolled hypercholesterolemia (total cholesterol >240mg/dl)
• any contraindication/nontolerance to the use of aspirin, heparin and/or clopidogrel
• lack of consent to participate