Objective To assess the efficacy and safety of fibfinogen-depleting agents (snake venom extracts) in the treatment of acute ischemic stroke. Method A systematic review of all the relevant randomized controlled trails (RCTs) was performed. RCTs were identified from the Cochrane Stroke Group’s Specialized Trials Register, additional electronic and handsearching, and personal contract with pharmaceutical companies. We included all completed and unconfounded truly or quasi-randomized trials in patients with ischemic stroke comparing fibrinogen depleting agents for analysis. Results Ten completed and one ongoing RCTs have been identified so far. Up to 1998, only three trials using ancrod (182 patients) met the inclusion criteria. Ancrod was associated with a significant reduction in early deaths (5.6% vs. 16%; odds ratio [OR], 0.33; 95% confidence interval [CI], 0.13 to 0.85; 2P=0.02) suggesting that treatment of 100 patients would avoid about 10 early deaths. The frequency of asymptomatic intracranial hemorrhage shown by computed tomography was similar between ancrod-treated and control groups (7.6% vs. 9.6%; OR 0.78; 95%CI 0.26 to 2.33; 2P=0.65). No major intracranial or extracranial hemorrhages or recurrent ischemic strokes occurred in the ancord-allocated patients. There were nonsignificant trends in favor of ancrod in death from any cause (OR 0.57; 95%CI 0.27 to 1.23; 2P=0.15) and death or disability (OR 0.52; 95%CI 0.26 to 1.03; 2P=0.06) at the end of trial follow-up. Up to 2000, other two trials published results. This review will be updated with new trial results soon, which will provide more data. Conclusions There were too few patients and outcome events to draw reliable conclusions from the present data. Although ancrod-like agents appeared promising, their routine use cannot be recommended at the moment. Future trials should test simpler fixed-dose regimens to allow better generalizability.
Objective To assess the effect of different thrombolytic agents, and different regimens in acute ischaemic stroke. Methods A systematic review of all the relevant randomized controlled trials (RCTs) was performed. RCTs were identified from the Cochrane Stroke Group trials register, Embase (1980 to 1997), handsearching Japanese and Chinese journals, and personal contact with pharmaceutical companies. We included randomised and quasi-randomised trials in patients with confirmed acute ischaemic stroke comparing different doses of a thrombolytic agent, or different thrombolytic agent, or the same agent given by different routes. Results Eight trials involving 1 334 patients were included. Concealment of allocation was generally adequate. All the trials were conducted in Japan. Different doses (of tissue plasminogen activator or urokinase) were compared in six trials. Different agents (tissue plasminogen activator versus urokinase,or tissue-cultured urokinase versus conventional urokinase) were compared in three trials. Few data were available for functional outcomes. A higher dose of thrombolytic therapy was associated with a five-fold increase in fatal intracranial haernorrhages (odds ratio 5.02, 95% confidence interval 1.56 to 16.18). There was a non-significant trend towards more early deaths or clinically significant intracranial haemorrhages in higher dose group. No difference in late deaths or extra-cranial haemorrhages was shown between low and higher doses. However, very few of these events occurred. No difference was shown between the different thrombolytic agents tested. Conclusions There is not enough evidence to conclude whether lower doses of thrombolytic agents might be safer or more effective than higher doses in acute ischaemic stroke. It is not possible to conclude whether one agent might be better than another, or which route of administration might be best.