***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background and Purpose — The relationship between the dose of recombinant tissue-type plasminogen activator ( r-tPA ) and its safety/efficacy for ischemic stroke has not been well evaluated in the East Asian population . We assessed the safety/efficacy of different doses of r-tPA for acute ischemic stroke in Chinese patients . Methods — A total of 1004 eligible patients were classified according to the dose of r-tPA received for managing acute ischemic stroke : 0.9 mg/kg ( n=422 ) , 0.8 mg/kg ( n=202 ) , 0.7 mg/kg ( n=199 ) , and 0.6 mg/kg ( n=181 ) . The safety outcome was symptomatic intracerebral hemorrhage and death within 3 months . The efficacy outcome was good functional outcome ( modified Rankin Scale ⩽1 ) at 3 months . Results — There was a significant trend for symptomatic intracerebral hemorrhage with age ( P=0.002 ) . With multivariate logistic regression analysis , a dose of 0.9 mg/kg was a predictor of symptomatic intracerebral hemorrhage ( P=0.0109 ) , and a dose ⩽0.65 mg/kg was a predictor of good functional outcome ( P=0.0369 ) . In patients aged 71 to 80 years , there was a significant trend of increasing symptomatic intracerebral hemorrhage ( P=0.0130 ) and less good functional outcome ( P=0.0179 ) with increasing doses of r-tPA . There was also a trend of increasing mortality ( P=0.0971 ) at 3 months in these patients . Conclusions — These results did not support the dose of 0.9 mg/kg of r-tPA being optimal for all patients in the East Asian population . In elderly patients ( 71–80 years ) , a lower dose of 0.6 mg/kg is associated with a better outcome . Confirmation of the results through r and omized trial is required Background and Purpose — The purpose of this study was to evaluate further the efficacy of 0.6 mg/kg intravenous alteplase on vascular and clinical outcomes in patients with middle cerebral artery occlusion in a postmarketing Phase IV trial of prospect i ve cohort study design . Methods — Alteplase was given intravenously at 0.6 mg/kg to patients with ischemic stroke within 3 hours of onset with MR angiography-documented middle cerebral artery occlusion .  Vascular outcome was evaluated by MR angiography at 6 and 24 hours after symptom onset based on the modified Mori grade . The primary end points also included a favorable outcome ( modified Rankin Scale 0 to 1 at 3 months after onset ) and incidence of symptomatic intracranial hemorrhage within 36 hours after treatment . The impact of recanalization on clinical outcome was assessed by stepwise logistic regression analysis . Results — Fifty-eight patients were enrolled .  Recanalization was noted in 51.7 % on 6-hour MR angiography and 69.0 % on 24-hour MR angiography . A favorable clinical outcome was achieved in 46.6 % . None had symptomatic intracranial hemorrhage . In logistic regression models , recanalization on either 6-hour or 24-hour MR angiography was an independent predictor for clinical outcome as well as the baseline National Institutes of Health Stroke Scale score . Conclusions — Early recanalization of an occluded middle cerebral artery can be provoked by 0.6 mg/kg intravenous alteplase and may induce a favorable clinical outcome . The rates of recanalization and favorable outcome are comparable to that previously reported with the 0.9-mg/kg dose Background —Arterial recanalization precedes clinical improvement or may lead to hemorrhage or reperfusion injury . Speed of clot lysis was not previously measured in human stroke . Methods and Results —Transcranial Doppler ( TCD ) and the National Institutes of Health Stroke Scale ( NIHSS ) were used to monitor consecutive patients receiving intravenous tissue plasminogen activator ( tPA ) , before tPA bolus and at 24 hours . Patients with complete or partial recanalization of the middle cerebral or basilar artery on TCD were studied . Recanalization was classified a priori as sudden ( abrupt appearance of a normal or stenotic low-resistance signal ) , stepwise ( flow improvement over 1 to 29 minutes ) , or slow ( ≥30 minutes ) . Recanalization was documented in  43 tPA-treated patients ( age 68±17 years ; NIHSS score 16.8±6 , median 15 points )  . tPA bolus was given at a mean of 135±61 minutes after symptom onset . Recanalization began at a median of 17 minutes and was completed at 35 minutes after tPA bolus , with mean duration of recanalization of 23±16 minutes . Recanalization was sudden in 5 , stepwise in 23 , and slow in 15 patients . Faster recanalization predicted better short-term improvement ( P = 0.03 ) . At 24 hours , 80 % , 30 % , and 13 % of patients in these respective recanalization groups had NIHSS scores of 0 to 3 . Symptomatic hemorrhage occurred in only 1 patient , who had stepwise recanalization 5.5 hours after stroke onset . Slow or partial recanalization with dampened flow signal was found in 53 % of patients with total NIHSS scores > 10 points at 24 hours ( P = 0.01 ) . Complete recanalization ( n=25 ) occurred faster ( median 10 minutes ) than partial recanalization ( n=18 ; median 30 minutes;P = 0.0001 ) . Conclusions —Rapid arterial recanalization is associated with better short-term improvement , mostly likely because of faster and more complete clot breakup with low resistance of the distal circulatory bed . Slow ( ≥30 minutes ) flow improvement and dampened flow signal are less favorable prognostic signs . These findings may be evaluated to assist with selection of patients for additional pharmacological or interventional treatment OBJECTIVES To assess time management of stroke thrombolysis triage and functional outcomes in patients receiving recombinant tissue plasminogen activator for hyperacute stroke , and identify bottlenecks in delivery of the treatment . DESIGN Prospect i ve study . SETTING A university teaching hospital in Hong Kong . PATIENTS Patients with suspected hyperacute stroke referred to the stroke thrombolysis team during October 2008 to September 2009 . MAIN OUTCOME MEASURES Time performance records including  door-to-stroke team , door-to-needle , and onset-to-thrombolysis times . Functional outcomes by modified Rankin Scale score at 3 months , and thrombolysis-related complications including haemorrhagic transformations and mortality . RESULTS During the 12-month period , 95 thrombolysis calls were received ; recombinant tissue plasminogen activator was given intravenously to 17 ( 18 % ) of the patients and intra-arterially to 11 ( 12 % ) . The mean ( st and ard deviation ) door-to-stroke team and the door-to-needle times for intravenous recombinant tissue plasminogen activator patients were 33 ( 25 ) and 80 ( 25 ) minutes , respectively ; both were about 20 minutes longer than that recommended by the National Institute of Neurological Disorders and Stroke . The mean National Institute of Health Stroke Scale score for patients received intravenous recombinant tissue plasminogen activator was 16 ( st and ard deviation , 7 ) . The mean ( st and ard deviation ) onset-to-treatment time was 144 ( 42 ) minutes . Nine ( 53 % ) patients who received intravenous recombinant tissue plasminogen activator achieved favourable outcomes at 3 months , with a modified Rankin Scale score of 0 to 1 . Symptomatic haemorrhage and mortality occurred in one ( 6 % ) patient . CONCLUSION A dedicated stroke triage pathway is essential to ensure efficient and safe delivery of thrombolysis therapy . Improvements in door-to-stroke team time through integration with emergency medicine staff and neuroradiologists may improve thrombolysis eligibility Background and Purpose — In Japan , alteplase at 0.6 mg/kg was approved in October 2005 for use within 3 hours of stroke onset by the Ministry of Health , Labor and Welfare ( MHLW ) . The aim of the Japan post-Marketing Alteplase Registration Study ( J-MARS ) , which was requested by MHLW at the time of approval , was to assess the safety and efficacy of 0.6 mg/kg alteplase in routine clinical practice for the Japanese . Methods — A total of 7492 patients from 942 centers were enrolled in the J-MARS , an open-label , nonr and omized , observational study , from October 2005 to October 2007 . Primary outcome measures were symptomatic intracranial hemorrhage ( a deterioration in NIHSS score ≥4 from baseline ) and favorable outcome ( modified Rankin Scale score , 0–1 ) at 3 months after stroke onset . Results — The proportion of patients with symptomatic intracranial hemorrhage in 7492 patients ( safety analysis ) was 3.5 % ( 95 % confidence interval [ CI ] , 3.1%–3.9 % ) within 36 hours and 4.4 % ( 95 % CI , 3.9%–4.9 % ) at 3 months . The overall mortality rate was 13.1 % ( 95 % CI , 12.4%–13.9 % ) and the proportion of patients with fatal symptomatic intracranial hemorrhage was 0.9 % ( 95 % CI , 0.7%–1.2 % ) . The outcomes at 3 months were available for 4944 patients and the proportion of favorable outcome ( efficacy analysis ) was 33.1 % ( 95 % CI , 31.8%–34.4 % ) . The subgroup analysis in patients between 18 and 80 years with a baseline NIHSS score < 25 demonstrated that favorable outcome at 3 months was 39.0 % ( 95 % CI , 37.4%–40.6 % ) . Conclusions — These data suggest that 0.6 mg/kg intravenous alteplase within 3 hours of stroke onset could be safe and effective in routine clinical practice for the Japanese Background and Purpose — The safety and efficacy of alteplase for ischemic stroke has not been examined in Chinese patients . We assessed the safety and efficacy of alteplase for acute ischemic stroke in daily clinical practice in Taiwan . Methods — A prospect i ve , multicenter , observational study was conducted in Taiwan from December 2004 to July 2008 . Eligible patients ( 241 ) receiving alteplase  were recruited and divided into 2 groups : st and ard dose ( 0.90±0.02 mg/kg , n=125 ) and lower dose ( 0.72±0.07 mg/kg , n=116 ) . Primary outcome measures were safety : symptomatic intracerebral hemorrhage and death within 3 months . The secondary outcome measure was efficacy a modified Rankin scale of 0 to 2 after 3 months . Results — The st and ard-dose group had higher rates of symptomatic intracerebral hemorrhage using National Institute of Neurological Diseases and Stroke , European Cooperative Acute Stroke Study , and Safe Implementation of Thrombolysis in Stroke-Monitoring Study definitions ( 10.4 % versus 5.2 % , 8.0 % versus 2.6 % , and 5.6 % versus 1.7 % , respectively ) and mortality within 3 months ( 12.8 % versus 6.9 % ) , twice that of the lower-dose group . This pattern was more prominent in older patients . Significantly higher rates of symptomatic intracerebral hemorrhage per European Cooperative Acute Stroke Study ( 15.4 % versus 3.3 % , P=0.0257 ) and mortality ( 21.1 % versus 5.0 % , P=0.0099 ) and significantly lower independence rate ( 32.6 % versus 53.6 % , P=0.0311 ) were observed among patients ≥70 years old receiving the st and ard dose than those receiving the lower dose . Conclusions — This study suggests that the st and ard dose of 0.9 mg/kg alteplase may not be optimal for treating aged Chinese patients . However , the dose of recombinant tissue plasminogen activator for ischemic stroke in Chinese patients should be based on more broad and convincing evidence s and r and omized trials of lower versus higher doses are needed Background and Purpose — Based on previous studies comparing different recombinant tissue plasminogen activator ( rt-PA ) doses , we performed a clinical trial with 0.6 mg/kg , which is lower than the internationally approved dosage of 0.9 mg/kg , aim ing to assess the efficacy and safety of alteplase in acute ischemic stroke for the Japanese . Methods — Our prospect i ve , multicenter , single-arm , open-label trial was design ed with a target sample size of 100 patients . The primary end points were the proportion of patients with a modified Rankin Scale ( mRS ) score of 0 to 1 at 3 months and the incidence of symptomatic intracranial hemorrhage ( sICH ) within 36 hours . Thresholds 
    Output:
    
The results remained consistent when sensitivity analyses were performed including only low-dose and st and ard-dose rtPA or only Asian studies .
Our review shows small difference between the outcomes or the risk profile in the studies using low-dose and /or st and ard-dose rtPA for AIS .
Low-dose rtPA was not associated with lower risk of death or disability , death alone , or sICH