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Anticoagulants for acute ischaemic stroke

This is not the most recent version

Abstract

Background

Most ischaemic strokes are caused by blood clots blocking an artery in the brain. Clot prevention with anticoagulants might improve outcome if bleeding risks were low. This is an update of a Cochrane review first published in 1995, and previously updated in 2004.

Objectives

To assess the effect of anticoagulant therapy versus control in the early treatment (less than 14 days) of patients with acute ischaemic stroke.

Search methods

We searched the Cochrane Stroke Group Trials Register (last searched 2 October 2007), and two Internet clinical trials registries for relevant ongoing studies (last searched October 2007).

Selection criteria

Randomised trials comparing early anticoagulant therapy (started within two weeks of stroke onset) with control in patients with acute presumed or confirmed ischaemic stroke.

Data collection and analysis

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted the data.

Main results

Twenty‐four trials involving 23,748 participants were included. The quality of the trials varied considerably. The anticoagulants tested were standard unfractionated heparin, low‐molecular‐weight heparins, heparinoids, oral anticoagulants, and thrombin inhibitors. Based on 11 trials (22,776 participants) there was no evidence that anticoagulant therapy reduced the odds of death from all causes (odds ratio (OR) 1.05; 95% confidence interval (CI) 0.98 to 1.12) at the end of follow up. Similarly, based on eight trials (22,125 participants), there was no evidence that anticoagulants reduced the odds of being dead or dependent at the end of follow up (OR 0.99; 95% CI 0.93 to 1.04). Although anticoagulant therapy was associated with fewer recurrent ischaemic strokes (OR 0.76; 95% CI 0.65 to 0.88), it was also associated with an increase in symptomatic intracranial haemorrhages (OR 2.55; 95% CI 1.95 to 3.33). Similarly, anticoagulants reduced the frequency of pulmonary emboli (OR 0.60; 95% CI 0.44 to 0.81), but this benefit was offset by an increase in extracranial haemorrhages (OR 2.99; 95% CI 2.24 to 3.99).

Authors' conclusions

Since the last version of the review, neither of the two new relevant studies have provided additional information to change the conclusions. In patients with acute ischaemic stroke, immediate anticoagulant therapy is not associated with net short or long‐term benefit. Treatment with anticoagulants reduced recurrent stroke, deep vein thrombosis and pulmonary embolism, but increased bleeding risk. The data do not support the routine use of any the currently available anticoagulants in acute ischaemic stroke.

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

Plain language summary

Anticoagulants for acute ischaemic stroke

Millions of people around the world have strokes every year. Most strokes take place when a blood clot blocks a blood vessel leading to the brain. Without a proper blood supply, the brain quickly suffers damage, which can be permanent. The damage from a stroke can cause arm or leg weakness, or difficulties with language or vision. Strokes are sometimes fatal, but will more often leave the survivor unable to do the things that they used to do. Because strokes are common and cause such damage, researchers are trying to find ways to get rid of the blood clot soon after the stroke happens. One way to do this is with blood thinning drugs called anticoagulants. If anticoagulants work, the bad effects of the stroke might be avoided. The main problem with anticoagulants is that they can cause bleeding, which can sometimes be very serious. This systematic review was designed to find out whether people treated with anticoagulants early after stroke got better or not, and whether they had problems with bleeding. There is a lot of information in this systematic review ‐ 23,748 people with stroke have been involved in 24 included randomised trials to answer this question. People treated with anticoagulants had less chance of developing blood clots in their legs and in their lungs following their stroke, but these benefits were offset by an increased risk of bleeding. More research is needed to find out if there are ways to select the people with stroke who will benefit from anticoagulants without suffering the bleeding complications. This review did not provide any evidence that the early use of anticoagulants is of overall benefit to people with strokes caused by blood clots. Anticoagulants did not reduce disability, and caused more bleeding.