To test the vasoactive and anti-inflammatory effects of prasugrel in patients with acute coronary syndrome endothelial function -as a surrogate parameter of NO bioavailability- and different markers of inflammation, oxidative stress and platelet activation will be assessed in patients with unstable angina.

Trial Objectives To test the vasoactive and anti-inflammatory effects of prasugrel in patients with acute coronary syndrome, endothelial function -as a surrogate parameter of NO bioavailability- and different markers of inflammation, oxidative stress and platelet activation will be assessed in patients with unstable angina.

Trial Design Single center, double blind, double-dummy, randomized, parallel trial.

Endpoints

Primary Endpoint Assessment of endothelial function (FMD) via high-resolution ultrasound (Sonoline G50, 12 MHz linear array transducer, Siemens, Germany) by experienced sonographer.

Secondary Endpoints

• Non-invasive assessment of microvascular perfusion and oxygen saturation by laser Doppler perfusion imaging and tissue spectrometry (O2C, Lea Medizintechnik, Giessen, Germany)
• Determination of leukocyte activity: plasma MPO levels (ELISA), plasma elastase levels (ELISA)
• Assessment of platelet activity: plasma levels of sCD40 ligand (ELISA), RANTES (ELISA)
• Measurement of different oxidative stress markers: hsCRP (ELISA), CD40 ligand (ELISA), carbonylated proteins (ELISA), urinary 8-iso-PGF2α (gas chromatography mass spectrometry)
• Determination of platelet-leukocyte aggregates by fluorescent activated cell sorter (FACS)
• Assessment of platelet function (PADA-test)

Inclusion Criteria:

• Acute coronary syndrome, unstable angina
• planned percutaneous coronary intervention
• Written informed consent

Exclusion Criteria:

• - Age < 18 years or ≥75 years
• Body weight < 60 kg
• STEMI, NSTEMI
• Cardiogenic shock at the time of randomization
• Refractory ventricular arrhythmias
• Congestive heart failure (NYHA IV)
• Increased risk of bleeding
• Active internal bleeding or history of hemorrhagic diathesis
• History of TIA, ischemic or hemorrhagic stroke
• Intracranial neoplasm, aneurysm and arteriovenous malformation
• INR > 1.5 at screening
• Platelets < 100,000/ml
• Anemia (Hb < 10 g/dl) at screening
• One or more doses of a thienopyridine 5 d or less before PCI
• Oral anticoagulation which cannot be safely discontinued for the duration of the study
• One or more doses of a thienopyridine 5 d or less before PCI
• Treatment within the last 30 d with an investigational drug or are presently enrolled in another drug or device study
• Women who are known to be pregnant, have given birth within the past 90 d, or are breast-feeding
• Concomitant medical illness that in the opinion of the investigator is associated with reduced survival over the expected treatment period
• Known severe hepatic dysfunction
• Any condition associated with poor treatment compliance, including alcoholism, mental illness, or drug dependence
• Intolerance of or allergy to aspirin, ticlopidine, or clopidogrel