BACKGROUND: Studies have demonstrated that immediate anticoagulation after thrombolysis can improve the prognosis of patients with acute cerebral infarction. However, the optimal timing and means of anticoagulation therapy remain unclear.OBJECTIVE: To observe the effects and safety of heparin treatment within 24 hours after intravenous thrombolysis for acute cerebral infarction.DESIGN: Observation experiment.SETTING: Department of Neurology, the 306 Hospital of Chinese PLA.PARTICIPANTS: Fifteen acute cerebral infarction patients complicated by moderate and severe neurologic function deficits within 6 hours after attack admitted to Department of Neurology, the 306 Hospital of Chinese PLA between January 2005 and December 2006 were recruited in this study. The involved patients,11 male and 4 female, were aged 46 - 79 years. They all met the diagnosis criteria for various cerebrovascular diseases formulated by the 4th National Conference for Cerebrovascular Disease (1995) and confirmed as cerebral infarction by skull CT or MRI imageology. Informed consents were obtained from the patients or their relatives.METHODS: On admission, patients received thrombolysis with urokinase. Immediately after thrombolysis,skull CT was rechecked. Intracranial hemorrhage signs were not found by skull CT. Hemorrhage was also not found in skin, mucous membrane and intal organs. Six hours later, low-dose low-intensity heparin 4 - 8 IU/kg per hour was intravenously administrated for anticoagulation for 7 - 10 days successively.MAIN OUTCOME MEASURES: Neurologic function was evaluated before, immediately 6 hours and 14 days after thrombolysis by scoring standard of clinical neurologic function deficit degree for stroke patients (1995). Activities of daily living of patients with stroke were evaluated 90 days after thrombolysis by modified Rankin Scale.RESULTS: Fifteen involved patients participated in the final analysis. ① Comparison of clinical neurologic function deficit degree of patients at different time: Neurologic function deficit score at the end of thrombolysis was significantly lower than that before thrombolysis (t =3.45, P ＜ 0.01). Neurologic function deficit score 6 hours after thrombolysis was higher than that at the end of thrombolysis, and neurologic deficits were increased, but no significant difference was found (P ＞ 0.05). Neurologic function deficit score 14 days after thrombolysis was significantly lower than that before thrombolysis (t =4.769, P ＜ 0.01). ②Therapeutic effect and modified Rankin scale results: 14 days after thrombolysis, 4 patients were basically cured, 7 significantly improved, 2 improved and 2 worsened. The total improvement rate of neurologic function deficit was 86.7%. Ninety days after thrombolysis, according to modified Rankin Scale, score was 0 to 2 in 12 patients (80%), 3 to 4 in 2 patients (13.3%) and 6 in 1 patient (6.7%). Complications of intracranial hemorrhage were not found in patients within 14 days after thrombolysis.CONCLUSION: Low-dose and low-intensity heparin applied within 24 hours after intravenous thrombolysis has good safety and efficacy in the treatment of acute cerebral infarction.