Differential Effect of Ticagrelor Versus Prasugrel Maintenance Dose on Endothelial Function of Peripheral Vessels in Patients With Coronary Artery Disease

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 prospective, randomized study with a crossover design, which will be conducted in patients with CAD under prasugrel maintenance dose (MD) 10mg once a day for at least a 3-month period. At Day 0 (day of randomization) eligible patients will be assigned to either:

* Ticagrelor 90mg twice a day for the next 15 days or * Prasugrel 10mg once a day for the next 15 days At Day 0 (before treatment onset)patients wiil be subjected to a baseline peripheral arterial tonometry measurement. Measurement will be repeated at Day 15 and then treatment crossover will be performed for the next 15 days (without an intervening washout period). At Day 30 patients will be subjected again to peripheral arterial tonometry assessment. Peripheral blood sample will be taken from the patients in Day 0 for genotyping control.