[Heparin during acute ischemic stroke. Present data and clinical situation]

Therapy with low- or high-dose heparin in acute stroke is changing. Despite several clinical studies (>20), some with quite large numbers of patients, no statistically significant benefit was found for the clinical endpoints of death and functional outcome. This negative result remains even when considering the preventive effect of high-dose heparin on secondary acute embolic events (e.g., cardiac emboli-arrhythmia) and low-dose heparin on venous thrombosis. Based on study results, most reviews and therapy recommendations for the treatment of acute stroke generally decline the use of high-dose heparins and heparinoids with full anticoagulation for improving outcome or preventing secondary embolic events as well as low-dose applications for venous thrombosis prophylaxis. This paper reviews the literature and presents the data of a standardised survey on coagulation therapy in acute stroke patients from all university and major stroke units in Germany (n=33). Contrary to the restrictive recommendations, therapy with heparin is firmly established in most stroke units. Full anticoagulation with heparin ("full dose") is performed on selected patients in 32/33 stroke units (97%). The selection criteria and thus the frequency of high-dose heparin use varies widely among the different centers. Almost all German stroke units (97%) routinely use low-dose heparin to prevent venous thrombosis and pulmonary embolism.The heparin agents and dosage, however, vary. These data correspond to those from the USA and Canada,where daily routine also departs from evidence-based treatment recommendations. That may be due to individual pathophysiological and aetiological considerations and of course the low acceptance of treatment recommendations based on classic, randomised trials. This underlines the need for new concepts (e.g.observational trials, continuous registers, etc.) addressing the adaptation of study-related conditions to the much more complex situation of daily routine (with risk/benefit, safety, and economic variables).