***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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    ***EXAMPLES*** 
    Input: BACKGROUND Post-thrombotic syndrome varies from mild oedema to incapacitating swelling with pain and ulceration . We investigated the rate of post-thrombotic syndrome after a first episode of deep-vein thrombosis and assessed the preventive effect of direct application of a sized-to-fit grade d compression stocking . METHODS Patients with a first episode of venogram-proven proximal deep-vein thrombosis were r and omly assigned no stockings ( the control group ) or made-to-measure grade d compression elastic stockings for at least 2 years . Post-thrombotic syndrome was assessed with a st and ard scoring system that combined clinical characteristics and objective leg measurements . Patients were assessed every 3 months during the first 2 years , and every 6 months thereafter for at least 5 years . The cumulative incidence of mild-to-moderate post-thrombotic syndrome was the primary outcome measure . FINDINGS Of the 315 consecutive out patients considered for inclusion , 44 were excluded and 77 did not consent to take part . 194 patients were r and omly assigned compression stockings ( n = 96 ) or no stockings ( n = 98 ) . The median follow-up was 76 months ( range 60 - 96 ) in both groups . Mild-to-moderate post-thrombotic syndrome ( score > or = 3 plus one clinical sign ) occurred in 19 ( 20 % ) patients in the stocking group and in 46 ( 47 % ) control-group patients ( p < 0.001 ) . 11 ( 11 % ) patients in the stocking group developed severe post-thrombotic syndrome ( score > or = 4 ) , compared with 23 ( 23 % ) patients in the control group ( p < 0.001 ) . In both groups , most cases of post-thrombotic syndrome occurred within 24 months of the acute thrombotic event . INTERPRETATION About 60 % of patients with a first episode of proximal deep-vein thrombosis develop post-thrombotic syndrome within 2 years . A sized-to-fit compression stocking reduced this rate by about 50 % Fibrinolytic treatment of acute deep vein thrombosis ( DVT ) of the leg with high-dose streptokinase ( SK ) ( 100,000 U/h ) in 39 cases , or low-dose SK ( approx 10,000 U/h ) in combination with low-dose heparin in 41 cases , was studied in a prospect i ve r and omized trial . The degree of thrombolysis was similar in both groups and did not correlate with age or size of the thrombus or with fibrinogen level . The degree of late recanalization was also similar in both groups . There were however significantly more patients with postthrombotic changes  in the low-dose group than in the high-dose group after a mean follow-up time of 31 and 38 months respectively . In the low-dose group 2 intracranial hemorrhages occurred ( one was fatal ) and one patient died of pulmonary embolism , but there were significantly less allergic side effects to SK .  There were no cases of such serious side effects in the highdose group . Although low-dose SK has equal thrombolytic effect it seems inferior to high-dose SK , since it probably causes more severe hemorrhagic side-effects In a prospect i ve study , 174 patients ( 118 women and 56 men , average age 44 years , range 14 to 82 ) with proximal extensive thrombosis received streptokinase ( 100,000 U/hour ) for an average of 2.8 days ( range 0.5 to 7 ) through the catheter of a temporary caval filter . Twenty-seven of 45 ( 60 % ) patients with nonocclusive clots were completely free of clots at the second phlebography versus 17 of 116 ( 14 % ) with occlusive clots ( p less than 0.001 ) . Among nonocclusive clots , proximal ones ( caval , iliac and femoral ) were more easily lysed than popliteal clots ( 88 of 116 [ 76 % ] vs 26 of 58 [ 45 % ] ; p less than 0.001 ) . In 41 of 132 ( 31 % ) patients , a daily injection of contrast medium through the filter-carrying catheter enabled the observation of a clot in the filter , which was lysed by streptokinase .  Seventy patients with follow-up greater than 2 years ( median 34 months ) were examined clinical ly . Nineteen of 22 ( 86 % ) patients with venograms free of clots at discharge were free of clinical sequelae versus 16 of 48 ( 33 % ) without normal venograms ( p less than 0.001 ) . It is concluded that : ( 1 ) in the case of occlusive clots , only a few patients were normalized after streptokinase ; ( 2 ) proximal nonocclusive clots were most effectively lysed ; ( 3 ) when venograms were free of clots at discharge , the majority of patients did not have venous sequelae at follow-up ; and ( 4 ) embolic migration seems to occur frequently with streptokinase Twenty patients with clinical signs of deep vein thrombosis of a duration not exceeding 72 hours , and with the condition confirmed phlebographically , were r and omly allocated to one of two groups in a double-blind study . In group 1 the patients received urokinase in a low-dose regimen of 200 000 Ploug units during the first 24 hours , followed by infusion of heparin , 40 000 units daily during the next 5 days . Patients in group 2 received heparin only , 40 000 units daily for 6 days . The clinical course was assessed daily . When the infusion period was completed , the phlebography was repeated , and the results of the two examinations were compared with respect to extent of filling defects and the degree of non-filling of the deep veins . We found no superiority in the regimen consisting of urokinase preceding heparin infusion , compared with that of heparin infusion alone . Most of the patients improved clinical ly during the 6-day infusion period , but the degree of thrombosis , evaluated phlebographically , was unaltered or even deteriorated during the period in all patients except two . Overt bleeding was noted in 6 patients Nineteen cases were reinvestigated 8 - 14 years after treatment with SK or heparin .  Judging from personal interviews , foot volumometry and phlebography , treatment with SK appears to be more preferable since it was less often followed by late severe postthrombotic changes In a prospect i ve study all  positive phlebographies within the well-defined population of the city of Malmö , Sweden , during 1987 were studied in order to determine the incidence of  deep venous thrombosis ( DVT ) .  Epidemiological data were analysed for the detection of patient groups at increased risk of DVT .  The incidence was found to be equal for both sexes , i.e. 1.6 per 1000 inhabitants a year . Risk factors were found to be in accordance with earlier studies . The median age for men was 66 years , compared to 72 years for women . At diagnosis of DVT , 19 % of subjects had a known malignancy and within 1 year 5 % ( 19 cases ) developed a new malignancy . Of the men , 29 % had  postoperative or post-traumatic ( fracture ) DVT  , compared to 46 % of the women . Fewer patients with DVT than expected ( 39 % ) belonged to blood group 0 ( 31 % ) ( P less than 0.005 ) . Pulmonary embolism ( PE ) was clinical ly suspected in only 5 % of cases , and diagnosis was verified scintigraphically in 2 % of cases . None of these died of PE , but of 6 patients who were found to have PE at autopsy , four died about 4 weeks after the DVT was diagnosed In a prospect i ve and r and omized multicenter trial the efficacy of intermittent regional and systemic thrombolytic therapy for DVT was evaluated . 137 patients with phlebographically confirmed acute DVT above the calf region were treated with 20 mg of rt-PA for 4 h each day . Thrombolysis was applied either locally via a dorsal pedal vein of the firmly b and aged affected leg or systemically using a cubital vein . Treatment lasted for 4 - 7 days , and during this time unfractionated heparin was applied continuously with the dosage adjusted according to aPTT ( 1.5 - 2.0 times the normal value ) . A second phlebography was performed within 24 h after the end of treatment . Results were evaluated by an independent radiologist who was unaware of the treatment given . Significant thrombolytic results ( e.g. lysis of more than 50 % of the original thrombus and complete recanalization of all affected veins ) were reached in only 1/3 of all patients . Rates of recanalization did not differ in both groups and bleeding complications occurred in 26.5 % . We conclude that intermittent local or systemic application of 20 mg rt-PA seems to be ineffective in the treatment of DVT Bolus urokinase ( Abbokinase ) is effective for initial treatment of deep venous thrombosis but is associated with a high rate of rigors . This r and omized controlled trial was undertaken among patients with deep venous thrombosis to evaluate the efficacy and safety of a novel thrombolytic agent , recombinant urokinase ( rUK ) , administered as three bolus infusions of 1 million U over a 24-hour period versus heparin alone . Of 361 patients with DVT screened , 17 ( 5 % ) were enrolled . Recent surgery was the most common reason for exclusion ( n = 113 , 31 % ) . Images of the patients were obtained at baseline , 24 to 48 hours after r and omization , and before hospital discharge . Two patients in each treatment group had minor clot progression . One patient in the heparin group had no change ; all other patients showed mild ( < 50 % ; n = 5 in each group ) or moderate ( > 50 % ; n = 1 in each group ) improvement . No bleeding complications or rigors developed in patients r and omized to rUK . Mean bleeding times among patients given rUK were not significantly different from mean values of patients given heparin at any of the measured time points available for comparison ( 331 vs 387 seconds at baseline and 381 vs 416 seconds at 24 hours ) . However , mean fibrinogen levels declined with successive urokinase boluses and were significantly lower than levels in patients treated with heparin at 24 ( 233 mg/dl vs 466 mg/dl , p = 0.01 ) and 48 hours ( 270 mg/dl vs 474 mg/dl , p = 0.02 ) . Although bolus rUK had a favorable safety profile , rUK was no more effective than heparin in achieving clot lysis at the doses used in this trial A controlled , prospect i ve study comparing streptokinase and heparin treatment has been completed in 51 patients presenting with acute proximal venous thrombosis of less than 8 days ' clinical duration . Patients were studied by means of pre‐treatment , post‐treatment , 3‐ and 12‐monthly phlebography and pulmonary perfusion scanning and were followed up at 3‐monthly intervals PURPOSE To compare the efficacy and safety of recombinant human tissue-type plasminogen activator ( rt-PA , supplied as Activase ) with heparin alone or rt-PA plus heparin in the treatment of venographically documented proximal deep venous thrombosis ( DVT ) of the leg . PATIENTS AND METHODS Sixty-four patients underwent 65 r and omizations to rt-PA alone ( n = 36 ) , rt-PA plus heparin ( n = 17 ) , or heparin alone ( n = 12 ) in a prospect i ve , multicenter , r and omized , open-label trial , with efficacy assessed by a radiology panel unaware of treatment assignment . Patients r and omly assigned to rt-PA received 0.05 mg/kg/hour for 24 hours via a peripheral vein , with a maximum dose of 150 mg . All patients then received heparin and warfarin for the remainder of the hospitalization . Follow-up venography was performed 24 to 36 hours after initiation of therapy . RESULTS Complete or more than 50 % lysis occurred in 10 ( 28 % ) patients treated with rt-PA , five ( 29 % ) patients with rt-PA plus heparin , and no patient treated with heparin .  No lysis occurred in 16 ( 44 % ) patients treated with rt-PA plus heparin , and 10 ( 83 % ) patients who received heparin alone ( p = 0.04 ) . There was one major complication , a nonfatal intracranial hemorrhage in a patient who received rt-PA alone . At 7 to 10 days after initiation of treatment , the level of serum glutamic oxaloacetic transaminase nearly doubled among all patients , including those assigned to receive heparin alone . CONCLUSION ( 1 ) rt-PA and rt-PA plus heparin cause more clot lysis than heparin alone ; ( 2 ) the addition of heparin to rt-PA does not improve the lysis rate ; ( 3 ) DVT treated with heparin is commonly associated with a rise in the transaminase level ; ( 4 ) 
    Output:
    
The authors determined that thrombolysis therapy results in greater lysis and complication rates than does anticoagulation alone .
The authors also found that PTS incidence is lower in patients treated with thrombolytics .
Therefore , the authors conclude that although the lysis rate is greater for thrombolytic agents , they can not be recommended routinely for DVT treatment