Inclusion Criteria- Age 18 to 80 years, both inclusive.
- Acute ischemic stroke, defined as an acute, focal, neurological deficit(s), secondary to an ischemic vascular event, which must include at baseline at least 1 of the following components as reflected by at least 1 point on items 9, 3 and 11 of the National Institutes of Health Stroke Scale (NIHSS), i.e. language dysfunction (aphasic disorder, excluding dysarthria), visual field defect (excluding monocular blindness), extinction and inattention.
- NIHSS above 5 and below 18 for left and right hemisphere strokes.
- Indication for the administration of intravenous tPA for acute stroke in accordance with tPA's authorized label for acute stroke.
- Pre-stroke modified Rankin Scale score lower or equal to 2.
- Ability to understand the requirements of the study and willing to provide written informed consent. In the event of incapacitated subjects, informed consent will be sought from a legally acceptable representative or by any other means as approved by the Ethics Committee.
- No contraindication to i.v. administration of iodinated contrast agent
Exclusion Criteria- Contraindications for tPA administration because of an increased risk of bleeding
- Known hypersensitivity to tPA or to iodinated contrast agents.
- Neurological deficit that has led to stupor or coma (NIHSS level of consciousness score above or equal to 2).
- Stroke 90 days before screening/baseline assessments that is either confirmed or assumed to be in the same cerebral territory as is the current acute stroke.
- Seizure any time between stroke symptoms onset and randomization.
- Life expectancy below 1 month.
- Serious illness, e.g. heart failure grade III or IV according to the New York Heart - Association functional classification, severe hepatic or renal failure.
- Neurological or non-neurological disease that in the investigator's opinion may confound the assessment of the treatment's safety or biological effects.
- Estimated creatinine clearance equal to or lower than 45 mL/min or dependency on renal dialysis.
- Treatment of the qualifying stroke with intravenous heparin unless activated partial thromboplastin time prolongation is not more than 2 seconds above the upper limit of normal for local laboratory prior to study drug initiation.
- Treatment of the qualifying stroke with a low molecular weight heparin or heparinoid.
- Female of childbearing potential who is not willing to use adequate and effective birth control measures for the duration of the trial.
- Positive urine pregnancy test at screening/baseline or lactating female.
- Body weight (measured or estimated) above 100 kg.
- Current drug or alcohol abuse.