Residual thrombosis of stent struts may occur after the end of primary angioplasty and determine distal embolization and further myocardial damage. Bivalirudin is considered the most appropriate antithrombotic drug in the setting of primary PCI, but an initial increase in stent thrombosis has been reported. In order to overcome this potential adverse event, a prolonged infusion of bivalirudin after the end of PCI has been proposed.

This aim of this study is to test whether the use of long-term bivalirudin infusion, as compared to the intra-procedural only administration, reduces residual thrombosis of stent struts evaluated by optical coherence tomography (OCT) at the end of primary PCI and at 3-5 days follow-up.

A subgroup of patients enrolled in the MATRIX (Minimizing Adverse haemmhorragic events by TRansradial access site and AngioX study) study will be selected showing the following inclusion criteria:

• patients affected by STEMI undergoing primary PCI with stent implantation and randomised to bivalirudin treatment,
• patients who, in addition to the infarct related lesion, show at least one critical stenosis of other coronary vessels suitable for staged-PCI,
• patients whose anatomy is suitable for OCT evaluation.

Inclusion Criteria:

• Patients enrolled in the MATRIX (Minimizing Adverse haemmhorragic events by TRansradial access site and AngioX study) study showing the following features:

  1. patients affected by STEMI undergoing primary PCI with stent implantation and randomised to bivalirudin treatment,
  2. patients who, in addition to the infarct related lesion, show at least one critical stenosis of other coronary vessels suitable for staged-PCI,
  3. patients with a coronary anatomy suitable for OCT evaluation.

Exclusion Criteria:

• The same criteria used in MATRIX (Minimizing Adverse haemmhorragic events by TRansradial access site and AngioX study) study.