Manipulation of coagulation factors in acute stroke.

In patients with an acute cerebral infarction, anticoagulation may spare tissue in the ischaemic penumbra from irreversible necrosis by preventing thrombus extension from a vascular bed with good collateral circulation to one with poor collateral circulation. In addition to the possibility of limiting infarct volume, anticoagulation may be given acutely to prevent early recurrent cerebral infarction or to prevent or treat thrombus outside the nervous system (i.e. deep venous thrombosis or pulmonary embolus). In one controlled trial of a low molecular weight heparin, administration of nadroparin calcium within 48 hours of onset of cerebral infarction decreased the combined incidence of dependency and all-cause mortality at 6 months. Another controlled trial in patients with cerebral venous thrombosis demonstrated the benefit of continuous intravenous adjusted-dose unfractionated (UF) heparin compared with placebo. Although results of anticoagulation appear promising in patients with acute cerebral infarction and cerebral venous thrombosis, the benefits of these agents remain unconfirmed. The results of large multicentre trials using a heparinoid (ORG 10172) and subcutaneous UF heparin in patients with acute cerebral infarction are expected within the year.