***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 
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    Input: Eighteen consecutive patients satisfying predefined clinical criteria for embolic strokes were prospect ively studied by sequential computerized tomography ( CT ) . Their findings were compared to CT scans obtained from patients presumed to have suffered thrombotic strokes . Our data reveal that the CT appearance of hemorrhagic infa rct ion is likely to occur twice as frequently ( 22 % ) in CT scans of strokes presumed embolic than in those presumed thrombotic , where hemorrhagic infa rct ion appeared at some time in 10 % of the patients . No patient deteriorated with anticoagulation regardless of the CT appearance . In patients showing hemorrhagic infa rct ion before anticoagulants , follow-up scans obtained after the administration of anticoagulants revealed resolution of the hemorrhagic aspect Background and Purpose — We sought to investigate the apparently high risk of early death after an ischemic stroke among patients with atrial fibrillation ( AF ) , identify the main factors associated with early death , and assess the effect of treatment with different doses of subcutaneous unfractionated heparin ( UFH ) given within 48 hours . Methods — We studied the occurrence of major clinical events within 14 days among 18 451 patients from the International Stroke Trial , first for all treatment groups combined . Then , among patients with AF , we examined the effects of treatment with subcutaneous UFH started within 48 hours and continued until 14 days after stroke onset . Results — A total of 3169 patients ( 17 % ) had AF . Seven hundred eighty-four patients were allocated to UFH 12 500 IU SC BID , 773 to UFH 5000 IU SC BID , and 1612 to no heparin . Within each of these groups , half of the patients were r and omly assigned to aspirin 300 mg once daily . Compared with patients without AF , patients with AF were more likely to be female ( 56 % versus 45 % ) , to be old ( mean age , 78 versus 71 years ) , to have an infa rct on prer and omization CT ( 57 % versus 47 % ) , and to have impaired consciousness ( 37 % versus 20 % ) . The initial ischemic stroke type was more often a large-artery infa rct ( 36 % versus 21 % ) . A lacunar stroke syndrome was less common ( 13 % versus 26 % ) . Death within 14 days was more common in patients with AF ( 17 % versus 8 % ) and more often attributed to neurological damage from the initial stroke ( 10 % versus 4 % ) . The frequency of recurrent ischemic or undefined stroke was not significantly different ( 3.9 % versus 3.3 % ) . The proportion of AF patients with further events within 14 days allocated to UFH 12 500 IU ( n=784 ) , UFH 5000 IU ( n=773 ) , and to no-heparin ( n=1612 ) groups were as follows : ischemic stroke , 2.3 % , 3.4 % , 4.9 % ( P = 0.001 ) ; hemorrhagic stroke , 2.8 % , 1.3 % , 0.4 % ( P < 0.0001 ) ; and any stroke or death , 18.8 % , 19.4 % and 20.7 % ( P = 0.3 ) , respectively . No effect of heparin on the proportion of patients dead or dependent at 6 months was apparent . Conclusions — Acute ischemic stroke patients with AF have a higher risk of early death , which can be explained by older age and larger infa rcts but not by a higher risk of early recurrent ischemic stroke , although slightly more patients with AF died from a fatal recurrent stroke of ischemic or unknown type ( 1.3 % versus 0.9 % ) . In patients with AF the absolute risk of early recurrent stroke is low , and there is no net advantage to treatment with heparin . These data do not support the widespread use of intensive heparin regimens in the acute phase of ischemic stroke associated with AF In a group of 60 patients in the acute phase of an ischemic stroke the assumption that low-molecular-weight heparin Kabi 2165 in the dose of 2 X 2,500 anti-Xa units s.c . could prevent thromboembolic complications was tested using a double-blind , placebo-controlled , r and omized trial design . Thirty patients were allocated to each group . Both treatment groups were comparable with regard to neurological status and general condition . In the Kabi 2165 group there were 6 cases of deep venous thrombosis ( DVT ) compared to 15 in the placebo group ( p = 0.05 ) . In the placebo group there were 4 deaths during the trial versus 9 in the Kabi-2165-treated group ( NS ) . Cerebral bleeding complicated 2 cases in the placebo group versus 4 in the Kabi 2165 group ( NS ) . These results indicate that in ischemic stroke patients  Kabi 2165 2 X 2,500 anti-Xa units s.c./24 h reduces the frequency of DVT . Because of the small number of patients it is impossible to evaluate the safety IN A PREVIOUS issue of this journa1,l the details of our national cooperative ControIled study of long-term anticoagulant therapy in cerebral ischemia and cerebral infa rct ion were presented along with an interim report covering some eighteen months . At that time , longterm anticoagulation did not appear to reduce the mortality and there was an added risk due to hemorrhagic complications . The study , embracing 7 clinical centers and extending over a period of forty-two months , was brought to an end in August 1961 , and this is a report of our findings and final conclusions . The important aspects of the study , including selection and classification of cases and method of anticoagulation , were fully covered previously and will not be repeated here . A total of 443 patients were enrolled in the study , each patient being assigned to the anticoagulant or nonanticoagulant therapeutic groups on a statistically r and om basis by means of sealed envelopes . All the patients in the study were divided into 5 diagnostic categories : ( 1 ) transient ischemic attacks , ( 2 ) thrombosis-in-evolution , ( 3 ) thrombosis-completed stroke , ( 4 ) thorem ( thrombosis or embolism ) , and ( 5 ) cerebral embolism . Analysis of the control and treated groups showed that they were remarkably comparable in most respects ( table 1 ) . The number of cases involving the internal carotidmiddle cerebral and vertebral-basilar systems varied from category to category ; in the whole series there were 328 in the carotid and 102 in the vertebral-basilar . In regard to blood pressure , 59.6 per cent of the entire group had an elevated blood pressure . To determine the effect of anticoagulant therapy , the cases were analyzed as to the incidence of ( 1 ) deaths , ( 2 ) progression of cerebral infa rct ion due to either extension of the infa rct ed area or a new infa rct ion , ( 3 ) the advent of extracerebral thrombotic episodes ( ECTE ) , including myocardial infa rct ion , pulmonary embolism , thrombophlebitis , and so forth , and ( 4 ) hemorrhagic complications . Patients whose anticoagulants were stopped within two weeks of death when the patient 's condition was deteriorating were reckoned as deaths while on anticoagulants The clinical features of 49 patients who had sustained small strokes in the internal carotid artery territory , who were normotensive , free from cardiac or other relevant disease , and who each had a normal appropriate single vessel angiogram are presented . These were r and omized into two groups : group A , 25 patients , who received only supportive treatment ; group B , 24 patients who were treated with anticoagulants for an average period of 18 months  . There was a reduced incidence of neurological episodes during the administration of anticoagulant therapy but , after treatment was discontinued , there was no significant difference between the two groups . In view of the relatively benign prognosis for this syndrome , unless special facilities exist for the personal control of anticoagulant treatment , the dangers may outweigh the benefits In a non‐r and omized controlled study carried out on 238 hospitalized patients with cerebral infa rct ion ,  anticoagulant treatment ( AC )  was compared with the natural course in the prevention of transient ischemic attacks ( TIA ) , cerebral infa rct ion , stroke , stroke or death . 137 patients were allocated to AC  , mean follow‐up 30.5 months , and 101 patients were allocated to the controls  ( untreated group ) , mean follow‐up 25.2 months In a double-blind , placebo-controlled trial , 225 patients with acute partial stable thrombotic stroke were r and omly assigned to receive continuous intravenous heparin therapy or placebo for 7 days for the prevention of stroke progression or death . No statistically significant difference between the two groups was found in degree of neurologic change ; incidence of stroke progression after 7 days ; or functional activity level of survivors at 7 days , 3 months and at 1 year after treatment . Compared with controls , a statistically significant greater number of patients in the group receiving heparin  died in the year after the stroke . These deaths occurred 3 to 12 months after the initial stroke and probably were not related to treatment . Results of this study do not support the use of intravenous heparin to treat patients who have had acute partial stroke Deep vein thrombosis ( DVT ) and subsequent pulmonary embolism ( PE ) is a major source of mortality and morbidity in stroke patients . This study was design ed to determine the effectiveness of different prophylactic treatments in the prevention of DVT after a stroke in patients undergoing rehabilitation . An additional objective was the identification of risk factors for DVT  in stroke in patients during rehabilitation . Three hundred and sixty patients , over a 3-year period , were r and omly assigned to one of four groups : adjusted dose heparin , intermittent pneumatic compression ( IPC ) , functional electrical stimulation ( FES ) , or control . There was no significant difference in the development of DVT by treatment group . Patients with DVT on admission ( prevalent , n = 61 ) were compared with the study patients ( n = 360 ) .  Time interval ( from stroke to admission ) and lactic dehydrogenase ( LDH ) concentration were significant risk factors , as well as predictors , for development of DVT ( p < .000 ) . These results suggest that the longer a patient remains without DVT prophylaxis after a stroke , the greater the risk of developing DVT and this supports early prophylaxis before rehabilitation Venous thrombo-embolism is a major and often unrecognized cause of morbidity and mortality in patients after acute strokes . Three hundred and five elderly patients were r and omly allocated to either control ( 161 ) or treatment ( 144 ) with 5000 units calcium heparin subcutaneously 8-hourly for two weeks . A reduction in deep-vein thrombosis rate from 72.7 % in the control group to 22.2 % in treatment patients was achieved . In patients who died ( 84 ) , post-mortem examination to look for pulmonary emboli was performed in 71 . Comparison between treated and untreated patients showed significantly fewer deaths and pulmonary emboli in the treated group . Most of the beneficial effect on mortality was seen in patients with lighter strokes . When patients with pulmonary emboli at post-mortem were excluded , there was no significant difference in the death rate in treatment ( 17 ) and control ( 14 ) groups . At post-mortem , 9.9 % of the strokes were haemorrhagic ( 4 in the treatment and 3 in the control group ) . Low-dose calcium heparin given subcutaneously following acute stroke reduced the number of deep-vein thromboses , pulmonary emboli and deaths without increasing the number of haemorrhagic strokes in this study We studied the effect of argatroban , a new selective thrombin inhibitor , on the haemostatic system in seven patients with acute ischaemic stroke ( the argatroban group ) .  Argatroban was infused continuously at 2.5 mg/h for the first 48 h , and then 10 mg of argatroban was infused over 3 h twice a day on days 3 - 7 . The  placebo group consisted of six acute ischaemic stroke patients . As a combination therapy , intravenous administration of glycerol was also performed at the same time in five of the seven patients in the argatroban group and in four of the six patients in the placebo group . D-dimer levels were measured by a latex photometric immunoassay that allowed immediate quantitative assessment . The D-dimer levels of our 13 patients with acute ischaemic stroke were raised at the time of admission ( day 1 ) and 69 % of the values were above the 97th percentile ( > 500 ng/ml ) in healthy subjects . D-dimer levels were significantly reduced in the argatroban group on days 2 and 7 after admission when compared with the placebo group ( day 2 : P = 0.032 ; day 7 : P = 0.046 ) . Thus , haemostatic activation occurred in acute ischaemic stroke was effectively blocked by argatroban A r and omized trial of immediate versus delayed anticoagulation of patients with cardiogenic embolic brain infa rct ion was carried out in a multi-centered study . Patients who were within 48 hours of onset of deficit and who had no evidence of hemorrhage on computed tomography ( CT ) were r and om 
    Output:
    
Sensitivity analyses did not identify a particular type of anticoagulant regimen or patient characteristic associated with net benefit .
REVIEW ER 'S CONCLUSIONS Immediate anticoagulant therapy in patients with acute ischaemic stroke is not associated with net short- or long-term benefit .
The data from this review do not support the routine use of any type of anticoagulant in acute ischaemic stroke