Intracranial hemorrhage, hemoptysis, retroperitoneal hemorrhage; aneurysm; serious disturbance of consciousness; recent (in the last 2 mth) intracranial or spinal surgery or w/ such injury. Atrial fibrillation (particularly w/ mitral stenosis), infective endocarditis, old MI, patients w/ prosthetic valve; patients w/ neurological signs & symptoms of stroke w/c became complete instantaneously.