***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 : Mechanical thrombectomy with a stent retriever applied shortly after symptom onset could increase good functional outcomes and improve survival in patients with acute basilar artery occlusion , but this has not yet been studied . This study evaluated the efficacy and safety of mechanical thrombectomy with a Solitaire stent within 8 hours of stroke onset in patients with acute basilar artery occlusion . MATERIAL S AND METHODS : We analyzed 25 consecutive patients with acute basilar artery occlusion who were treated with mechanical thrombectomy by use of the Solitaire stent within 8 hours of stroke symptom onset .  Successful recanalization was defined as TICI grade 2b or 3 . Good outcome was defined as mRS score of 0–2 at 3 months . Clinical and radiologic data in patients with good outcomes were compared with those with poor outcomes . RESULTS : Successful recanalization was achieved in 96 % ( 24/25 ) of patients , and 48 % ( 12/25 ) of patients had good outcomes . Eighty-eight percent ( 22/25 ) of patients survived to 3 months . The median NIHSS score on admission was significantly lower in patients with good outcomes than in those with poor outcomes ( 9.5 versus 14 , P = .005 ) . Procedure-related complications occurred in 2 patients ( 8 % ) . No symptomatic intracerebral hemorrhages occurred . CONCLUSIONS : The current study suggests that mechanical thrombectomy by use of a Solitaire stent within 8 hours of stroke onset increases good outcomes and improves survival in patients with acute basilar artery occlusion BACKGROUND Among patients with acute ischemic stroke due to occlusions in the proximal anterior intracranial circulation , less than 40 % regain functional independence when treated with intravenous tissue plasminogen activator ( t-PA ) alone . Thrombectomy with the use of a stent retriever , in addition to intravenous t-PA , increases reperfusion rates and may improve long-term functional outcome . METHODS We r and omly assigned eligible patients with stroke who were receiving or had received intravenous t-PA to continue with t-PA alone ( control group ) or to undergo endovascular thrombectomy with the use of a stent retriever within 6 hours after symptom onset  ( intervention group ) . Patients had confirmed occlusions in the proximal anterior intracranial circulation and an absence of large ischemic-core lesions . The primary outcome was the severity of global disability at 90 days , as assessed by means of the modified Rankin scale ( with scores ranging from 0 [ no symptoms ] to 6 [ death ] ) . RESULTS The study was stopped early because of efficacy . At 39 centers , 196 patients underwent r and omization ( 98 patients in each group ) . In the intervention group , the median time from qualifying imaging to groin puncture was 57 minutes , and the rate of substantial reperfusion at the end of the procedure was 88 % . Thrombectomy with the stent retriever plus intravenous t-PA  reduced disability at 90 days over the entire range of scores on the modified Rankin scale ( P<0.001 ) . The rate of functional independence ( modified Rankin scale score , 0 to 2 ) was higher in the intervention group than in the control group ( 60 % vs. 35 % , P<0.001 ) . There were no significant between-group differences in 90-day mortality ( 9 % vs. 12 % , P=0.50 ) or symptomatic intracranial hemorrhage ( 0 % vs. 3 % , P=0.12 ) . CONCLUSIONS In patients receiving intravenous t-PA for acute ischemic stroke due to occlusions in the proximal anterior intracranial circulation , thrombectomy with a stent retriever within 6 hours after onset improved functional outcomes at 90 days . ( Funded by Covidien ; SWIFT PRIME Clinical Trials.gov number , NCT01657461 . ) Background and Purpose — In middle cerebral artery occlusion , probability of recanalization after intravenous tissue-type plasminogen activator thrombolysis ( IVT ) was reported to drop < 1 % for thrombi exceeding 8 mm . We aim ed to evaluate the effect of thrombus length and location on success of recanalization after IVT in basilar artery occlusion . Methods — We evaluated 164 consecutive patients with angiography-proven basilar artery occlusion and available thrombus length . We excluded 24 patients who underwent endovascular treatment . All included patients ( n=140 ) received IVT . Thrombolysis in myocardial infa rct ion 2 to 3 was considered as successful recanalization . Results — Of the 140 included patients , 37 ( 26.4 % ) lacked post-treatment angiography  , mostly because of early death . Of the remaining 103 patients , those with recanalization had shorter thrombi ( median , 5.5 mm and mean , 9.7 mm ) when compared with those with nonrecanalized ( median , 15.0 mm and mean , 16.6 mm ; P<0.001 ) . Thrombi shorter than 10 mm had 70 % to 80 % probability of recanalization , whereas 10 to 20 mm , 20 to 30 mm , and > 30 mm long thrombi had probabilities of 50 % to 70 % , 30 % to 50 % , and 20 % to 30 % , respectively . Patients with thrombi < 10 mm ( n=52 ) and recanalization had more frequently top-of-the basilar ( 92.5 % ) and less frequently caudal or midbasilar ( 7.5 % ) clot location ( P=0.01 ) . In multivariable analysis , thrombus length was independently associated with recanalization ( P=0.001 ) . Their relationship remained linear across all lengths . Conclusions — Although recanalization of basilar artery occlusion with IVT depends on thrombus length , its probability even in patients with thrombi > 30 mm ( 20%–30 % ) was substantially higher than minimal recanalization of middle cerebral artery thrombi exceeding 8 mm . There was no threshold length , beyond which basilar artery occlusion recanalization with IVT could ad hoc be deemed hopeless BACKGROUND Treatment strategies for acute basilar artery occlusion ( BAO ) are based on case series and data that have been extrapolated from stroke intervention trials in other cerebrovascular territories , and information on the efficacy of different treatments in unselected patients with BAO is scarce . We therefore assessed outcomes and differences in treatment response after BAO . METHODS The Basilar Artery International Cooperation Study ( BASICS ) is a prospect i ve , observational registry of consecutive patients who presented with an acute symptomatic and radiologically confirmed BAO between November 1 , 2002 , and October 1 , 2007 .  Stroke severity at time of treatment was dichotomised as severe ( coma , locked-in state , or tetraplegia ) or mild to moderate ( any deficit that was less than severe ) . Outcome was assessed at 1 month . Poor outcome was defined as a modified Rankin scale score of 4 or 5 , or death . Patients were divided into three groups according to the treatment they received : antithrombotic treatment only ( AT ) , which comprised antiplatelet drugs or systemic anticoagulation ; primary intravenous thrombolysis ( IVT ) , including subsequent intra-arterial thrombolysis ; or intra-arterial therapy ( IAT ) , which comprised thrombolysis , mechanical thrombectomy , stenting , or a combination of these approaches . Risk ratios ( RR ) for treatment effects were adjusted for age , the severity of neurological deficits at the time of treatment , time to treatment , prodromal minor stroke , location of the occlusion , and diabetes . FINDINGS 619 patients were entered in the registry . 27 patients were excluded from the analyses because they did not receive AT , IVT , or IAT , and all had a poor outcome . Of the 592 patients who were analysed , 183 were treated with only AT , 121 with IVT , and 288 with IAT . Overall , 402 ( 68 % ) of the analysed patients had a poor outcome . No statistically significant superiority was found for any treatment strategy . Compared with outcome after AT , patients with a mild-to-moderate deficit ( n=245 ) had about the same risk of poor outcome after IVT ( adjusted RR 0.94 , 95 % CI 0.60 - 1.45 ) or after IAT ( adjusted RR 1.29 , 0.97 - 1.72 ) but had a worse outcome after IAT compared with IVT ( adjusted RR 1.49 , 1.00 - 2.23 ) . Compared with AT , patients with a severe deficit ( n=347 ) had a lower risk of poor outcome after IVT ( adjusted RR 0.88 , 0.76 - 1.01 ) or IAT ( adjusted RR 0.94 , 0.86 - 1.02 ) , whereas outcomes were similar after treatment with IAT or IVT ( adjusted RR 1.06 , 0.91 - 1.22 ) . INTERPRETATION Most patients in the BASICS registry received IAT . Our results do not support unequivocal superiority of IAT over IVT , and the efficacy of IAT versus IVT in patients with an acute BAO needs to be assessed in a r and omised controlled trial . FUNDING Department of Neurology , University Medical Center Utrecht BACKGROUND In patients with acute ischemic stroke caused by a proximal intracranial arterial occlusion , intraarterial treatment is highly effective for emergency revascularization . However , proof of a beneficial effect on functional outcome is lacking . METHODS We r and omly assigned eligible patients to either intraarterial treatment plus usual care or usual care alone .  Eligible patients had a proximal arterial occlusion in the anterior cerebral circulation that was confirmed on vessel imaging and that could be treated intraarterially within 6 hours after symptom onset . The primary outcome was the modified Rankin scale score at 90 days ; this categorical scale measures functional outcome , with scores ranging from 0 ( no symptoms ) to 6 ( death ) . The treatment effect was estimated with ordinal logistic regression as a common odds ratio , adjusted for prespecified prognostic factors . The adjusted common odds ratio measured the likelihood that intraarterial treatment would lead to lower modified Rankin scores , as compared with usual care alone ( shift analysis ) . RESULTS We enrolled 500 patients at 16 medical centers in The Netherl and s ( 233 assigned to intraarterial treatment and 267 to usual care alone ) . The mean age was 65 years ( range , 23 to 96 ) , and 445 patients ( 89.0 % ) were treated with intravenous alteplase before r and omization . Retrievable stents were used in 190 of the 233 patients ( 81.5 % ) assigned to intraarterial treatment . The adjusted common odds ratio was 1.67 ( 95 % confidence interval [ CI ] , 1.21 to 2.30 ) . There was an absolute difference of 13.5 percentage points ( 95 % CI , 5.9 to 21.2 ) in the rate of functional independence ( modified Rankin score , 0 to 2 ) in favor of the intervention ( 32.6 % vs. 19.1 % ) . There were no significant differences in mortality or the occurrence of symptomatic intracerebral hemorrhage . CONCLUSIONS In patients with acute ischemic stroke caused by a proximal intracranial occlusion of the anterior circulation , intraarterial treatment administered within 6 hours after stroke onset was effective and safe . ( Funded by the Dutch Heart Foundation and others ; MR CLEAN Netherl and s Trial Registry number , NTR1804 , and Current Controlled Trials number , IS RCT N10888758 . ) Background Despite recent advances in acute stroke treatment , basilar artery occlusion ( BAO ) is associated with a death or disability rate of close to 70 % . R and omised trials have shown the safety and efficacy of intravenous thrombolysis ( IVT ) given within 4.5 h and have shown promising results of intra-arterial thrombolysis given within 6 h of symptom onset of acute ischaemic stroke , but these results do not directly apply to patients with an acute BAO because only few , if any , of these patients were included in r and omised acute stroke trials . Recently the results of the Basilar Artery International Cooperation Study ( BASICS ) , a prospect i ve registry of patients with acute symptomatic BAO challenged the often-held assumption that intra-arterial treatment ( IAT ) is superior to IVT . Our observations in the BASICS registry underscore that we continue to lack a proven treatment modality for patients with an acute BAO and that current clinical practice varies widely . Design BASICS is a r and omised controlled , multicentre , open label , phase III intervention trial with blinded outcome assessment , investigating the efficacy and safety of additional IAT after IVT in patients with BAO . The trial targets to include 750 patients , aged 18 to 85 years , with CT angiography or MR angiography confirmed BAO treated with IVT . Patients will be r and omised between additional IAT followed by optimal medical care versus optimal medical care alone . IV 
    Output:
    
Conclusions : The data from this meta- analysis suggest a possible superiority of SRT over IVT , pending positive results of r and omized controlled trials .