Study of Tirofiban Administration in Patients With Aspirin and or Clopidogrel Resistance

Inclusion Criteria: 1. All Patients older than 18 years scheduled for coronary angiography and/or PCI will be enrolled. \[Patients should be CK-MB negative (to avoid CK washout with revascularization) and also cTnI/T negative whereas other high-risk features will not lead to patient exclusion. 2. All consecutive patients with stable or unstable troponin and CK-MB negative coronary artery disease showing aspirin and or clopidogrel resistance (ACR) will be enrolled. These include: * Patients with clinical indication to undergo angiography for possible revascularisation. * Patients with ACR in whom catheter-based coronary intervention is planned based on previous angiogram. Exclusion Criteria: 1. Patients who can not give informed consent or have a life expectancy of \< 1 year 2. Evolving or Ongoing myocardial infarction (MI) (Persistence of or developing Q wave or ST segment elevation at ECG with or without typical chest pain or typical rapid rise and fall CK-MB or new LBBB) or patients in whom the treating physician intends to use a Gp IIB/IIIa inhibitors. 3. Administration of any GP IIb/IIIa receptor antagonist, anticoagulation, or lytic therapy in the previous 30 days 4. Serum creatinine more than 2.5 mg/dl (221 micromol/L) 5. Ongoing bleeding or bleeding diathesis or contraindication for anticoagulation or increase bleeding risk or history of bleeding in the last 1 year 6. Previous stroke or TIA or any intracranial pathology in the last six months 7. Major surgery or trauma within the previous six weeks 8. Platelet count \< 100.000 per cubic mm or HCT ,33% or Hb \< 11 gm/dL 9. Subjects who received low-molecular-weight heparin within the 24 hours prior to randomization 10. Subjects with an allergy or intolerance to aspirin, heparin, clopidogrel, or tirofiban 11. Patients with severe hypertension (SBP \> 180 mm Hg or DBP \> 110 mm Hg) or in cardiogenic shock (SBP 80 mm Hg or below for \> 30 minutes) or requiring IABP