The objective of this study is to investigate whether intravenous administration (injected into a vein) of acetylsalicylic acid (Aspirin) in doses of 250 and 500 mg is superior to oral treatment of ACS with tablets containing 300 mg of Aspirin.

In November 2009 it was the company's decision to cancel this study as an international trial. However, to support the local MA application of Aspirin i.v. for the indication "For the initial treatment in case of suspicion of acute coronary syndrome", Bayer decided to perform this trial in Germany as a domestic trial, with changed number of participants and study dates.

Inclusion Criteria:

• Angina pectoris lasting for more than 20 minutes within the last 24 hours before study drug treatment (or equivalent acute symptoms such as increasing dyspnea, diaphoresis, nausea, abdominal/epigastric pain, syncope etc.)
• ECG change suggestive for ischemia:
• ST elevation or T-wave change or ST depression, new or presumed left bundle-branch block (LBBB)
• Elevated troponin T level > 0.01 ng/ml, levels according to local laboratory reference values
• Risk factors for ACS such as known coronary artery disease (CAD), diabetes mellitus, impaired renal function, peripheral artery or cerebrovascular disease, current smoking.

Exclusion Criteria:

• Treatment with acetylsalicylic acid (ASA) within 48 hours prior to study drug treatment
• Treatment with glycoprotein IIa/IIIb inhibitors within 48 hours prior to study drug treatment and before the 20 minutes blood samples for thromboxane, prostacycline and platelet aggregation measurement have been taken
• Thrombolytic therapy within 24 hours before study drug treatment
• Obligation for tracheal intubation and mechanical ventilation
• Contraindications to ASA treatment
• Known haemorrhagic diathesis
• Evidence of an active gastrointestinal or urogenital bleeding
• Stroke within 3 months prior to study drug treatment
• Major surgery including coronary artery bypass graft (CABG) within 6 weeks prior to study drug treatment
• Known severe hepatic or renal insufficiency
• Pregnant or breast-feeding women