ANTITHROMBIN-III ACTIVITY AND THE EFFICACY OF HEPARIN IN PROGRESSING ISCHEMIC STROKE

Heparin is often used in progressing ischemic stroke. However, a subst antial part of the patients continue to progress while on treatment. T he purpose of this study was to evaluate if antithrombin (AT) III acti vity before treatment could predict patients at risk for continued pro gression or if heparin-induced reduction in AT-III activity during tre atment is related to continued progression. The study included 42 acut e stroke patients with heaprin treatment for progression of ischemic s troke. The patients were continuously supervised for progression. intr avenous heparin therapy was started as soon as possible after the prog ression was noticed. Antithrombin-III activity was assessed before ini tiation of treatment and daily during the treatment period. Nine (21%) of the 42 patients continued to progress while on treatment. There wa s no statistically significant difference in AT III activity before tr eatment between patients who continued to progress and those where the progression ceased when treatment was initiated. Nor were there any d ifferences in the mean AT III activity levels during treatment for pat ients with more or less favorable clinical course. The individual chan ges (Delta AT III) were similar in both patient groups as was the prop ortion of patients with their lowest AT III activity in the thrombogen ic range (continued: 22% vs. ceased: 27%). No clinically relevant infl uence of AT III activity on heparin efficacy in progressing ischemic s troke was found.