Antithrombotic therapy in the acute phase: new approaches

Both anticoagulants and antiplatelet agents have been advocated, used and studied for the treatment of acute ischemic stroke. Randomized trials of unfractionated heparin, low-molecular-weight heparin and heparinoids have failed to show an overall benefit to these agents largely because the benefits in reducing thromboembolic events are offset by the increased risk of bleeding complications. The International Stroke Trial, the Trial of ORG 10172 Acute Stroke Treatment and studies of fraxaripine all failed to show an overall benefit to anticoagulation in the patients studied. Aspirin has been shown to offer a modest benefit when studied in patients treated within 48 h of stroke onset. Ancrod is an antithrombotic agent that acts by reducing circulating fibrinogen levels. Patients treated within 3 h of stroke symptom onset had a better functional outcome at 90 days compared to placebo-treated patients with both the benefits and the risk of intracerebral bleeding related to the fibrinogen lowering achieved. Abciximab is a blocker of the platelet GPIIb/IIIa receptor. A dose finding safety study suggests that in doses up to that typically given in patients with acute coronary occlusion syndromes, there is no increased risk of symptomatic intracerebral bleeding and suggestions of potential benefits on neurological outcome.