Haemodilution for acute ischaemic stroke.

BACKGROUND

Ischaemic stroke interrupts the flow of blood to part of the brain. Haemodilution is thought to improve the flow of blood to the affected areas of the brain.

OBJECTIVES

The objective of this review was to assess the effects of haemodilution in acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Medline and conference abstracts. We contacted manufactures and investigators in the field.

SELECTION CRITERIA

Randomised trials of haemodilution treatment in people with acute ischaemic stroke. Only trials where treatment was started within 72 hours of stroke onset were included.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and independently extracted the data.

MAIN RESULTS

Sixteen trials were included. A combination of venesection and plasma volume expander was used in eight trials. Eight trials used plasma volume expander alone. The plasma volume expander was dextran 40 in 11 trials, hydroxyethyl starch in four trials and albumin in one trial. Two trials tested haemodilution in combination with another therapy. Evaluation was blinded in 11 trials. Five trials probably included some patients with intracerebral haemorrhage. Haemodilution did not significantly reduce deaths within seven to 28 days (odds ratio 1.12, 95% confidence interval 0.88 to 1.43). Similarly, haemodilution did not influence deaths within three to six months (odds ratio 1.02, 95% confidence interval 0.85 to 1.23), or death and dependency or institutionalisation (odds ratio 1.01, 95% confidence interval 0.86 to 1.19). The results were similar in confounded and unconfounded trials, in trials of isovolaemic and hypervolaemic haemodilution, and in trials using different types of hemodiluting agents. Six trials reported venous thromboembolic events. There was a tendency towards reduction in deep venous thrombosis and/or pulmonary embolism at three to six months follow-up (odds ratio 0.59, 95% confidence interval 0.33 to 1.06).

REVIEWER'S CONCLUSIONS: The overall results of this review are compatible both with a modest benefit and a moderate harm of haemodilution therapy for acute ischaemic stroke. As used in the randomised trials, this therapy has not been proven to improve survival or functional outcome.