***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 feasibility , safety , and efficacy of intravenous tissue plasminogen activator ( t-PA ) for patients with acute ischemic stroke in clinical practice need to be assessed . METHODS We initiated a prospect i ve open-label study at a university hospital and two community hospitals in Houston , Tex , immediately after the publication of the National Institute of Neurological Disorders and Stroke ( NINDS ) t-PA study . A total of 30 patients , age 32 to 90 years , were treated with 0.9 mg/kg of intravenous t-PA ( maximum dose , 90 mg ) within 3 hours of acute ischemic stroke between December 1995 and December 1996 . RESULTS Six percent ( 6 % ) of all patients hospitalized with ischemic stroke received intravenous t-PA at the university hospital and 1.1 % at the community hospitals . The rates of total , symptomatic , and fatal intracerebral hemorrhage were 10 % , 7 % , and 3 % . Thirty-seven percent ( 37 % ) of patients recovered to fully independent function . The average time from stroke onset to emergency department arrival was 57 minutes ; emergency department arrival to computed tomography scan 41 minutes ; and computed tomography scan to administration of treatment 59 minutes . CONCLUSIONS When treatment guidelines are carefully followed in an urban hospital setting , intravenous t-PA for acute ischemic stroke is feasible and shows safety and efficacy comparable to the results of the NINDS study Objective : To study the short and long term differences in outcome between patients ⩾80 years of age and those ⩽79 years of age who received intravenous recombinant tissue plasminogen activator ( iv rt-PA ) for acute stroke within the first 3 hours of symptom onset . Methods : We studied consecutive patients treated with iv rt-PA for acute stroke , with prospect i ve follow up of up to 3 years . Outcome measures included National Institutes of Health Stroke Scale ( NIHSS ) score , Barthel Index ( BI ) , modified Rankin score ( MRS ) , and stroke mortality . Patients were split into two groups : younger ( ⩽79 years ) and older ( ⩾80 years ) . Results : There were 65 patients in the younger cohort and 31 patients in the older . Older patients were more likely to present with more severe baseline stroke ( p = 0.04 ; odds ratio ( OR ) 3.04 ; 95 % confidence interval ( CI ) 1.03 to 8.98 ) . Stroke mortality at 90 days was 10.8 % in the younger and 32.3 % in the older cohort ( p = 0.01 ) . At 90 days ’ follow up , patients in the older cohort with more severe stroke ( NIHSS score ⩾11 ) were nearly 10 times more likely to have poor outcome compared with their younger counterparts presenting with severe stroke ( p = 0.001 ; OR = 10.36 ; 95 % CI 2.16 to 49.20 ) . Baseline stroke severity and age were the only independent and equal predictors for stroke outcome . No threshold was found for age or baseline stroke severity predicting outcome . Conclusion : Older patients presenting with more severe baseline stroke are much less likely to benefit from iv rt-PA as compared with their younger counterparts Background —Intravenous recombinant tissue plasminogen activator ( rtPA ) is an effective therapy for acute ischemic stroke , but it is associated with risk of intracerebral hemorrhage ( ICH ) . Our aim was to identify , in a large cohort of patients , readily available baseline factors that are associated with thrombolysis-related ICH . Methods and Results —In a multicenter retrospective and prospect i ve investigation of individual data from 1205 patients treated in routine clinical practice with intravenous rtPA within 3 hours of stroke symptom onset , 72 patients ( 6 % ) developed symptomatic ICH and 86 additional patients ( 7 % ) had asymptomatic ICH identified on a routine follow-up CT . In analyses based on clinical variables alone , the main attributes associated with ICH were a history of diabetes mellitus and cardiac disease , increasing stroke severity , advancing age , use of antiplatelet agents other than aspirin before stroke onset , and elevated pretreatment mean blood pressure . In additional analyses that incorporated baseline CT and laboratory findings ( in a subset of patients ) , the main associations were early ischemic CT changes , in particular if exceeding one third of middle cerebral artery territory ; increasing stroke severity ; diabetes mellitus or elevated serum glucose ; and lower platelet counts . Final independent attributes associated with parenchymatous hematoma , defined by purely radiologically based criteria , were similar to those of symptomatic ICH . Conclusions —Readily available factors can identify acute ischemic stroke patients at high and low risk for rtPA-related  ICH . These factors require confirmation in a prospect i ve cohort before clinical implementation Background and Purpose — Iron overload has been associated with greater oxidative stress and brain injury in experimental cerebral ischemia and reperfusion . This study investigates whether high serum ferritin levels , as an index of increased cellular iron stores , are associated with poor outcome , hemorrhagic transformation , and brain edema after treatment with tissue plasminogen activator in patients with acute ischemic stroke . Methods — A total of 134 consecutive patients treated with intravenous tissue plasminogen activator were prospect ively studied in four centers .  Serum ferritin levels were determined at baseline , 24 and 72 hours after treatment . Cranial computed tomography was performed on admission and at 24 to 36 hours after tissue plasminogen activator infusion .  Stroke severity and outcome were evaluated by using the National Institute of Health Stroke Scale and the modified Rankin Scale . Results — Computed tomography showed hemorrhagic transformation in 27 patients ( hemorrhagic infa rct ion in 15 and parenchymal hematoma in 12 ; symptomatic in four ) and brain swelling with midline shift in 15 . Poor outcome ( modified Rankin Scale > 2 ) at 90 days was observed in 54.5 % of patients . Ferritin levels at baseline were higher in patients with poor outcome at 90 days ( median [ quartiles ] , 165 [ 98,307 ] versus 17 [ 12,37 ] ng/mL ; P<0.001 ) and in those who developed parenchymal hematoma ( P=0.006 ) , symptomatic hemorrhagic transformation ( P=0.008 ) , and severe brain edema ( P<0.001 ) . Serum ferritin levels higher than 79 ng/mL before tissue plasminogen activator treatment were independently associated with poor outcome ( OR , 117 [ 95 % CI , 25 to 557 ] ) . Conclusions — Increased body iron stores are associated with poor outcome , symptomatic hemorrhagic transformation , and severe edema in patients treated with tissue plasminogen activator after ischemic stroke . These findings suggest that iron overload may offset the beneficial effect of thrombolytic therapies Background and Purpose — Patients with right hemispheric strokes ( RHSs ) present later to an emergency department , have a lower chance to receive intravenous recombinant tissue plasminogen activator ( IV rt-PA ) , and have worse clinical outcomes than do patients with left hemispheric strokes ( LHSs ) . We analyzed outcomes after IV rt-PA with respect to the side of the affected hemisphere . Methods — A prospect i ve cohort of acute stroke patients was treated with IV rt-PA at the London Health Sciences Centre ( December 1998 to March 2003 ) . Differences between patients with RHS and LHS were identified by univariate analysis . Logistic-regression analysis was used to determine a subset of variables independently associated with major neurological improvement at 24 hours and good outcome at 3 months after treatment . Results — Of 219 stroke patients who received IV rt-PA , 165 had hemispheric strokes ( 68 RHSs and 97 LHSs ) . Patients with RHSs were less hypertensive ( P=0.001 ) and had lower pretreatment National Institutes of Health Stroke Scale ( NIHSS ) scores ( P=0.005 ) . LHS ( odds ratio [ OR ] , 2.29 ; 95 % CI , 1.14 to 4.59 ; P=0.019 ) , age ( OR , 0.96 ; 95 % CI , 0.93 to 0.99 ; P=0.012 ) , and pretreatment NIHSS ( OR , 0.83 ; 95 % CI , 0.78 to 0.89 ; P<0.0001 ) were independent predictors of 3-month outcome . Female sex ( OR , 3 ; 95 % CI , 1.53 to 5.90 ; P=0.001 ) and LHS ( OR , 2.07 ; 95 % CI , 1.05 to 4.08 ; P=0.03 ) were independent predictors of major neurological improvement at 24 hours after IV rt-PA . Conclusions — Despite higher pretreatment NIHSS , patients with LHSs have a 2-fold increased chance of a good outcome 3 months after rt-PA treatment compared with patients with RHSs . This gain can be clinical ly detected at 24 hours after treatment . These results need to be coupled with neuroimaging and hemodynamic characteristics known to influence stroke outcome Background and Purpose — The Safe Implementation of Thrombolysis in Stroke-MOnitoring STudy ( SITS-MOST ) unadjusted results demonstrated that intravenous alteplase is well tolerated and that the effects were comparable with those seen in r and omized , controlled trials ( RCTs ) when used in routine clinical practice within 3 hours of ischemic stroke onset . We aim ed to identify outcome predictors and adjust the outcomes of the SITS-MOST to the baseline characteristics of RCTs . Methods — The study population was SITS-MOST ( n=6483 ) and pooled RCTs ( n=464 ) patients treated with intravenous alteplase within 3 hours of stroke onset . Multivariable , backward stepwise regression analyses ( until P≤0.10 ) were performed to identify the outcome predictors for SITS-MOST . Variables appearing either in the final multivariable model or differing ( P<0.10 ) between SITS-MOST and RCTs were included in the prediction model for the adjustment of outcomes . Main outcome measures were symptomatic intracerebral hemorrhage , defined as National Institutes of Health Stroke Scale deterioration ≥1 within 7 days with any hemorrhage ( RCT definition ) , mortality , and independency as defined by modified Rankin Score of 0 to 2 at 3 months . Results — The adjusted proportion of symptomatic intracerebral hemorrhage for SITS-MOST was 8.5 % ( 95 % CI , 7.9 to 9.0 ) versus 8.6 % ( 6.3 to 11.6 ) for pooled RCTs ; mortality was 15.5 % ( 14.7 to 16.2 ) versus 17.3 % ( 14.1 to 21.1 ) ; and independency was 50.4 % ( 49.6 to 51.2 ) versus 50.1 % ( 44.5 to 54.7 ) , respectively . In the multivariable analysis , older age , high blood glucose , high National Institutes of Health Stroke Scale score , and current infa rct ion on imaging scans were related to poor outcome in all parameters . Systolic blood pressure , atrial fibrillation , and weight were additional predictors of symptomatic intracerebral hemorrhage . Current smokers had a lower rate of symptomatic intracerebral hemorrhage . Disability before current stroke ( modified Rankin Score 2 to 5 ) , diastolic blood pressure , antiplatelet other than aspirin , congestive heart failure , patients treated in new centers , and male sex were related to high mortality at 3 months . Conclusions — The adjusted outcomes from SITS-MOST were almost identical to those in relevant RCTs and reinforce the conclusion drawn previously in the unadjusted analysis . We identified several important outcome predictors to better identify patients suitable for thrombolysis Background : Predictors of outcome and safety in intravenous thrombolysis within 3 h in clinical routine is a matter of ongoing debate . Available reports contain small patient numbers or summarize heterogeneous multicenter data . Methods : Four hundred and fifty patients received intravenous thrombolysis within 3 h after stroke . Pretreatment NIHSS score and detailed medical history were analyzed . Noncontrast CT was performed before thrombolysis , 24–36 h later and in case of clinical deterioration . Symptomatic intracranial hemorrhage ( SICH ; any bleeding with an NIHSS increase of ≧4 points ) and clinical outcome ( modified Rankin Scale , mRS ) after 3 months were recorded . Logistic regression identified parameters predictive of independence ( mRS 0–2 ) and SICH . Results : Median onset to admission , door to needle and onset to treatment time was 75 , 50 and 135 min , respectively . Direct presentation by emergency service ( 64 % ) was the fastest way of referral . Median pretreatment NIHSS was 11 points . Independence ( mRS 0–2 ) was reached by 53 % . Mortality was 11 % ( 7 % intracerebral , 4 % extracerebral complications ) . Logistic regression identified low 
    Output:
    
These results suggest no gender difference in outcome among patients treated with intravenous rtPA