Inclusion Criteria:  Patients with previous coronary stent implantation and a posterior catheterization performed > 8 months after the index procedure due to clinical follow-up (those ones with bare metal stents without restenosis will be included in the group of controls and those with restenosis will be included in the group of cases, 20 with bare metal and 20 with drug eluting stents). Age 18-75 years.  Exclusion Criteria:  Patients on chronic anti-inflammatory treatment, including corticosteroids. Patients with previous or current history of malignancy or any other disease mediated by inflammation.