intravenous rt-PA is effective to reduce the risk of death or dependency after ischaemic stroke. This effect is due to an early recanalization secondary to the lysis of the clot. However this effect may be counterbalanced by the increased risk of bleeding and also the neurotoxicity of rt-PA, which has been shown in animals to depend on the ratio single chain (sc) / double chain (tc) in the rt-PA administered. The main objective of OPHELIE is to determine whether the functional outcome after treatment by iv rt-PA depends on the ratio sc-rtPA / tc-rtPA. Secondary objectives were to identify the influence on the risk of brain haemorrhage, and the influence of the cognitive state (OPHELIE-COG substudy).

OPHELIE is a multicenter study conducted in France in 25 centers where patients treated by iv rt-PA will be included. Patients are treated according to the local protocol, without any modification specifically for this study. A sample of 2 drops of the rt-PA used for the treatment is stored for analysis, to determine the sc-tPA/tc-tPA ration (immunostaining).

700 patients are needed for the study assuming that a difference of 5% will be found in the primary outcome measure (modified Rankin scale 0-1 at 3 months) with alpha and beta risks respectively of 5% and 20%.

The participating clinical centres recruit altogether more than 500 patients per year for thrombolysis. Assuming that 70% will be eligible, the recruitment should take less than 2 years.

Inclusion Criteria:

• Being treated by iv tPA for acute cerebral ischaemia

Exclusion Criteria:

• absence of reliable informant
• no rtPA left in the syringe after treatment

Patients treated in routine by iv t-PA for acute ischaemic stroke