Abstract: ［Abstract］ Objective〖HTSS〗〓To investigate the relationship between serum homocysteine(Hcy) level and prognosis of acute ischemic stroke（AIS）in the old elderly patients who received thrombolysis of recombinant tissue plasminogen activator(rtPA).
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Fortyseven patients were recruited according to the research criteria and were grouped by their serum Hcy levels.The patients were divided into 24 cases in the high level （Hcy≥18.54 μmol/L） group(group A) and 23 cases in the low level（Hcy＜18.54 μmol/L） group(group B).The data including age, sex, cerebrovascular disease risk factors, onset to needle time, blood glucose level, blood lipids levels, uric acid level, fibrinogen level, hemoglobin level, platelets count,stroke subtypes and clinical outcome were analyzed.All patients took CT/MRI examination to detect cerebral hemorrhage in 24 hours after rtPA treatment. Neurological function was evaluated by National Institute of Health Stroke Scale(NIHSS) score and modified Rankin Scale(MRS) score. The clinical outcome was scored according to the MRS and considered as poor when the MRS score was equal or greater than 4 after 90 days of thrombolysis.Risk factors influencing the prognosis of patients with acute ischemic stroke after thrombolysis were assessed and cutoff values of Hcy were calculated if Hcy level can be used as an index to predict the outcome.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓The Hcy mean level of all patients was higher than normal, which were associated with diabetes, smoking, alcohol consumption, uric acid level and hemoglobin level.After 1week rtPA treatment, the NIHSS scores of high Hcy level group were significantly higher than those of low level group(P＜0.05), meantime the high Hcy group showed obvious symptomatic intracerebral hemorrhage risk after 24 hours(P＜005). Poor outcome was presented in MRS score results after 3 months in high Hcy level group, compared with low Hcy level group(P＜005). The Hcy level and initial NIHSS score were risk factors for poor prognosis in old elderly patients with AIS receiving thrombolytic treatment of rtPA with apotentially optimal cutoff value of Hcy at 21.35 μmol/L(sensitivity 78.6%, specificity 63.3%).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Elevated Hcy level is a potential independent predicter of poor prognosis in the old elderly patients with AIS after rtPA treatment，while the probable optimal cutoff value is 21.35 μmol/L.

Key words: stroke； homocysteine, thrombolysis, aged, 80 and over