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Antiplatelet therapy in patients with subarachnoid haemorrhage

Three Part Question

In [patients with a definite subarachnoid haemorrhage] does the administration of an [antiplatelet drug] improve [outcome]?

Clinical Scenario

A 51 year old male presents to an Emergency Department with a history of a sudden-onset, worst-ever occipital headache. An urgent CT scan confirms a subarachnoid haemorrhage and arrangements are made for transfer to the regional neurosurgical unit. You administer nimodipine as recommended by the neurosurgical team. You wonder, given the risks and likely mechanism of secondary ischaemia and infarction whether administration of an anti-platelet therapy would benefit the patient.

Search Strategy

Using the Ovid interface the Cochrane Database of Systematic Reviews, CINAHL, EMBASE and Ovid MEDLINE were searched in October 2008.
[ OR [[ OR OR] AND] AND [ OR OR OR platelet aggregation OR OR glycoprotein OR acetylsalicylic] LIMIT to English language and human.

Search Outcome

379 papers were found in total. One Cochrane review was felt to be relevant to the three-part question. No papers, other than those already included in the Cochrane Review were felt to be relevant.

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Dorhout Mees SM, van den Bergh WM, Algra A, Rinkel GJ
1385 patients with subarachnoid haemorrhage included in seven randomised controlled trials.Systematic Review looking for benefits and adverse effects of antiplatelet therapy for subarachnoid haemorrhage.Reduction in poor outcomeRR 0.79, 95% CI 0.32 to 1.01
Reduction in secondary brain ischaemiaRR 0.79, 95% CI 0.56 - 1.22
Risk of intracranial haemorrhagic complicationsRR 1.36, 95% CI 0.59 - 3.12


Although there is a trend towards better outcome for patients and a reduction in secondary ischaemia these trends do not reach statistical significance. There is also the serious potential of adverse events in the form of further intracranial haemorrhage.

Clinical Bottom Line

There is insufficient evidence to advocate the administration of antiplatelet agents to patients with subarachnoid haemorrhage.

Level of Evidence

Level 1 - Recent well-done systematic review was considered or a study of high quality is available.


  1. Dorhout Mees SM, van den Bergh WM, Algra A, Rinkel GJ Antiplatelet therapy for aneurysmal subarachnoid haemorrhage Cochrane Database of Systematic Reviews 4):CD006184, 2007