Ticagrelor administration, whose molecule resembles to adenosine, led to reduction in overall mortality and thrombotic cardiovascular (CV) events when directly compared to clopidogrel in the PLATO trial, implicating possible pleiotropic actions for the drug. It has been shown that ticagrelor increases adenosine concentration, by interfering with its red blood cells' uptake and by inducing the release of ATP which is then converted to adenosine. Recent studies in healthy volunteers and patients with coronary artery disease (CAD) have shown that ticagrelor increases the coronary blood flow in response to intravenous adenosine administration. Ticagrelor administration, in comparison with other P2Y12 inhibitors, may influence the endothelial function, as assessed by the Peripheral Arterial Tonometry method (EndoPAT 2000 system (Itamar Medical, Caesarea, Israel), which is a method for evaluating endothelial dysfunction and has been found to positively correlate with flow mediated dilatation (FMD).

This is a prospective, observational study, which will be conducted in patients with coronary artery disease subjected to percutaneous coronary intervention (PCI) under ticagrelor maintenance dose (MD) 90mg x 2, who are about to stop treatment, due to completion of 1 year antiplatelet therapy. Eligible patients will be subjected to peripheral arterial tonometry at Day 0 (immediately after receiving the last pill of ticagrelor) and at day 2 and day 5 post study drug discontinuation. Peripheral blood sample will be taken from the patients at Day 0 for genotype analysis.

Inclusion Criteria:

1. Age above 18-80 years old
2. Patients with Coronary Artery Disease receiving ticagrelor maintenance dose (MD) 90mg x 2 and are about to discontinue the treatment due to the completion of 1 year of dual antiplatelet therapy.
3. Patients giving written Informed Consent.

Exclusion Criteria:

1. Acute Coronary Syndrome
2. Foreseeable need for anticoagulant treatment within the next 5 days
3. Severe non-regulated with theophylline/aminophylline administration chronic obstructive pulmonary disease
4. Creatinine Clearance <30ml/min/1.73mm2
5. HbA1c > 10mg/dl

Patients with coronary artery disease under ticagrelor maintenance dose, who are about to discontinue ticagrelor, due to completion of 12 months dual antiplatelet therapy.