Bleeding complications in secondary stroke prevention by antiplatelet therapy: a benefit-risk analysis

This review analyses the benefit-risk ratio of antiplatelet drugs in secondary stroke prevention and is based on the published data from eight large stroke prevention trials. In patients with prior transient ischaemic attack (TIA) or stroke, aspirin prevented one to two vascular events (stroke, AMI, or vascular death) per 100 treatment-years with an excess risk of fatal and severe bleeds of 0.4-0.6 per 100 treatment-years. The gastrointestinal bleeding risk was significantly lower with ticlopidine and clopidogrel, which were both somewhat more effective than aspirin in the prevention of vascular events. The combination of dipyridamole and aspirin prevented 2.82 strokes at the expense of an excess risk of 0.61 (95% CI = 0.27-0.95) fatal or severe bleeds per 100 treatment-years. In the acute phase of stroke, the aspirin-associated risk of haemorrhagic complications was much increased compared with that in the stable phase after stroke, with 0.48 (95% CI = 0.13-0.83) fatal or severe bleeds per 100 treated patients for the first 4 weeks after stroke in the Chinese Acute Stroke Trial and 0.41 (95% CI = 0.05-0.77) in the International Stroke Trial. Still, there was a net benefit with the prevention of about one death or non-fatal ischaemic stroke per 100 treated patients.