Bleeding occurring during percutaneous coronary interventions (PCI has now emerged as one of the most common complication of PCI and adversely affect in-hospital, short- and long-term outcome.As bivalirudin proved its effectiveness in decreasing haemorrhagic events during PCI, its administration may be advocated in subjects deemed at high risk of bleeding.Objective of the present trial is to compare the safety and effectiveness of procedural use of bivalirudin in comparison to unfractionated heparin (UFH) in patients undergoing PCI deemed at high risk of procedural bleeding.