***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: BACKGROUND Venous thromboembolism is known to be an important social and health care problem because of its high incidence among patients who undergo surgery . Studies on the mechanical prophylaxis of thromboembolism after gynaecological pelvic surgery are few . The aim of our study was to evaluate the effect of mechanical thromboembolism prophylaxis after gynaecological pelvic surgery using a combination of graduated compression stockings ( GCS ) and intermittent pneumatic compression ( IPC ) or GCS alone . METHODS The study was performed on 108 patients who were r and omly assigned to two groups . The first group received GCS before the operation and IPC during the operation ( IPC + GCS group ) . The second group received GCS before the operation ( GCS group ) . To analyze the effect of the preventive measures and the laboratory examination on the incidence of thrombosis and to compare the safety of these measures , the incidence of adverse reactions was assessed . RESULTS The morbidity associated with DVT was 4.8 % ( 5/104 ) in the IPC + GCS group and 12.5 % ( 14/112 ) in the GCS group . There were significant statistical differences between the two groups . There were no adverse effects in either group . CONCLUSIONS The therapeutic combination of GCS and IPC was more effective than GCS alone for thrombosis prevention in high-risk patients undergoing gynaecological pelvic surgery , and there were no adverse effects in either group We studied 80 patients who were older than 50 years of age to determine if grade d elastic compression stockings reduced the frequency of postoperative thrombosis in patients undergoing dextran 70 prophylaxis . All of the patients received a total of 2,000 mL of dextran 70 during three days ; according to a r and om table , each of the patients had one leg encased in a grade d compression stocking for one week . Thrombosis development was screened with the fibrinogen I 125 test . Eight patients manifested thrombosis-one in the thigh and seven in the calf -- localized to the unstockinged leg , a frequency significantly greater than the zero frequency in the stockinged leg . No untoward effects of this combination prophylaxis were noted INTRODUCTION Darexaban ( YM150 ) is an oral direct factor Xa inhibitor in clinical development for prophylaxis of venous thromboembolism ( VTE ) after major orthopaedic surgery . The objective of this study was to assess the efficacy and safety of darexaban 15 mg twice daily ( bid ) in Japanese patients undergoing major abdominal surgery . MATERIAL S AND METHODS In a Phase III , multicentre , r and omized , open-label , mechanical prophylaxis-controlled , parallel-group study , adult patients ( aged ≥ 40 years ) were r and omized to darexaban 15 mg bid or mechanical prophylaxis , for 28 days . The primary efficacy outcome was incidence of total VTE at Day 12 . Adverse events ( AEs ) and bleeding events were recorded throughout the study . RESULTS The total VTE incidence at Day 12 was 2.6 % in the darexaban 15 mg bid group ( 95 % confidence interval [ CI ] : 0.32 , 9.07 ) , compared with 15.0 % ( 95 % CI : 5.71 , 29.84 ) in the mechanical prophylaxis group . During the investigational period , the incidence of all bleeding events was 9.5 % in the darexaban 15 mg bid group and 3.9 % in the mechanical prophylaxis group . In the darexaban 15 mg bid group , one patient experienced major bleeding and five patients experienced clinical ly relevant non-major ( CRNM ) bleeding . No patients in the mechanical prophylaxis group experienced major and /or CRNM bleeding . AEs were reported in 71.4 % of patients in the darexaban 15 mg bid group and 76.5 % of patients in the mechanical prophylaxis group ; the most frequent AEs across both treatment groups were constipation and insomnia . No patients died during the study . CONCLUSIONS Based on these findings , darexaban is expected to be effective for the prevention of VTE in patients undergoing major abdominal surgery . ( CLINICAL TRIAL REGISTRATION NUMBER NCT00942435 ) A study of 95 patients determined the incidence of postoperative venous thrombosis  and the effectiveness of simple prophylactic measures . In addition , the accuracy of the radioactive fibrinogen technique for the detection of thrombosis was compared to venography .  Deep venous thrombosis was detected in six of 44 ( 14 % ) control patients . However , only two of 51 ( 4 % ) patients on whom prophylactic measures were applied developed thrombosis . The  ages of the patients with thrombosis occurring postoperatively were significantly higher than the ages of the other patients in this study . There was an excellent correlation of the results obtained by the radioactive method with those of venography . Laboratory tests indicated a deficient endogenous fibrinolytic activity in those patients who developed thrombosis The effect of incremental increases in external pressure , applied to the leg , on blood volume flow in the femoral vein was studied in dogs . Clinical investigation of external pressure increases was also carried out on nine patients undergoing surgery for varicose veins . An external pressure between 5 and 15 mm . Hg caused a sustained increase in mean femoral vein flow both in a control and in the compressed limb . Above 15 mm . Hg external pressure flow decreased in the compressed limb but was maintained at an increased level in the control limb . If external compression is to be used to prevent and treat deep vein thrombosis its application must be carefully controlled Lower‐limb venous haemodynamics were studied prospect ively in 40 patients ( 24 women , 16 men of median age 52 years ) undergoing laparoscopic cholecystectomy . Patients were r and omized to wear compression stockings during surgery or no stockings . All received subcutaneous heparin prophylaxis . Venous capacitance and outflow were measured non‐invasively before , during and after pneumo‐peritoneum . In the group without compression stockings ( 20 patients ) venous capacitance and outflow decreased during pneumoperitoneum in most patients . In the group wearing stockings ( 20 patients ) the changes were less pronounced or abolished . There was a significant difference between the groups in venous capacitance and outflow ratios at mid‐operation : median ( interquartile range ) 0‐89 ( 0‐56‐1‐16 ) and 0‐89 ( 0‐56‐1‐15 ) respectively in the group without stockings versus 1‐48 ( 1‐09‐2‐19 ) and 1‐71 ( 1‐20‐2‐19 ) respectively in that with stockings ( P < 0.001 ) . Pneumoperitoneum creates a significant resistance to venous return . Compression stockings counteract the changes observed In a prospect i ve , r and omized study on 114 patients undergoing major abdominal surgery , the prophylactic effect of dihydroergotamine ( DHE ) combined with low-dose heparin ( LDH ) against postoperative deep vein thrombosis ( DVT ) was compared with that of peroperative intermittent pneumatic calf compression ( IPCC ) . The additive effect of graduated pressure stockings was also studied , by r and omizing a stocking to the right or left leg in each patient . The  125I-fibrinogen test was used to diagnose DVT . The incidence of postoperative DVT was significantly lower in the DHE-LDH than in the IPCC group ( 4 % v. 19 % ) . In the IPCC group the incidence of postoperative DVT was equal in legs with and without stocking . The study thus indicated that DHE-LDH is more effective than peroperative IPCC in preventing DVT after major abdominal surgery , and that graduated pressure stockings do not enhance the prophylactic effect of peroperative IPCC Purpose Venous thromboembolism ( VTE ) is a frequent and serious problem in intensive care units ( ICU ) . Anticoagulant treatments have demonstrated their efficacy in preventing VTE . However , when the bleeding risk is high , they are contraindicated , and mechanical devices are recommended . To date , mechanical prophylaxis has not been rigorously evaluated in any trials in ICU patients . Methods In this multicenter , open-label , r and omized trial with blinded evaluation of endpoints , we r and omly assigned 407 patients with a high risk of bleeding to receive intermittent pneumatic compression ( IPC ) associated with graduated compression stockings ( GCS ) or GCS alone for 6 days during their ICU stay . The primary endpoint was the occurrence of a VTE between days 1 and 6 , including nonfatal symptomatic documented VTE , or death due to a pulmonary embolism , or asymptomatic deep vein thrombosis detected by ultrasonography systematic ally performed on day 6 . Results The primary outcome was assessed in 363 patients ( 89.2 % ) . By day 6 , the incidence of the primary outcome was 5.6 % ( 10 of 179 patients ) in the IPC + GCS group and 9.2 % ( 17 of 184 patients ) in the GCS group ( relative risk 0.60 ; 95 % confidence interval 0.28–1.28 ; p = 0.19 ) . Tolerance of IPC was poor in only 12 patients ( 6.0 % ) . No intergroup difference in mortality rate was observed . Conclusions With the limitation of a low statistical power , our results do not support the superiority of the combination of IPC + GCS compared to GCS alone to prevent VTE in ICU patients at high risk of bleeding Totally , 150 patients , subjected to total hip arthroplasty , were r and omly allocated into three prophylactic groups with either conventional dextran alone or with additional grade d compression stockings or with additional preoperative administration of dextran . The overall frequency of deep venous thrombosis ( DVT ) , as studied by radioactive fibrinogen uptake test and ascending phlebography of the operated on thigh was in the conventional dextran group 46 percent , the additional stockinged group 30 percent , and in the additional preoperative dextran group 52 percent . In the stockinged group , there was a lower frequency of DVT in the nonoperated on leg as well as , on an average , about 350 mL less peroperative bleeding as compared with the other two groups . No adverse reaction occurred from dextran administration . Increased and prolonged postoperative administration of dextran decrease the number of femoral DVTs Postoperative thromboembolic complications were evaluated in 2578 patients undergoing elective abdominal surgery , all receiving prophylaxis with low molecular weight heparin .  A positive fibrinogen uptake test ( FUT ) developed in 217 patients ( 8.4 % ) , while 37 patients ( 1.4 % ) had major thromboembolism ( TE , defined as proximal deep vein thrombosis and /or pulmonary embolism , verified with phlebography , pulmonary scintigraphy or autopsy ) . In only 14 % a positive FUT was associated with a major TE event . In 19 % of the patients with major TE the FUT was negative . In multiple logistic regression the independent predictors for major TE were partially different from those for positive FUT . Thirty day mortality was 3.0 % . There were significant associations between both positive FUT and major TE on one h and and mortality on the other ( relative risks 2.4 and 5.8 , respectively ) . FUT is not a good predictor of major TE . Both positive FUT and major TE indicate a significant risk of postoperative death Seventy-eight patients having elective total hip replacement were r and omised into 3 groups A ) control ; B ) low molecular weight heparin : ( enoxaparin 40 mg once daily ) and C ) enoxaparin ( 40 mg once daily ) plus graduated elastic compression ( TEDR stockings ) for 8 - 12 days . All patients had a preoperative perfusion lung scan and chest X-Ray and a postoperative perfusion/ventilation scan together with bilateral ascending venography on days 8 - 12 . A blood sample was taken preoperatively , on the 1st , 3rd and 5th postoperative day and at the end of the study . The control group received placebo injections . The venograms and V/Q scans were reported blindly by an independent panel of three and one radiologists respectively . An independent panel of assessors stopped entry in the control group when a total of 45 patients were admitted according to Ethics Committee directives . The study continued with groups B and C. The incidence of DVT ( including isolated asymptomatic calf thrombi ) was as follows : Group A ( n = 14 ) 93 % ; Group B ( n = 32 ) 38 % ; Group C ( n = 32 ) 25 % ( chi 2 ; p < 0.001 for group A versus B or C ) . The incidence of proximal DVT was : Group A 57 % ; group B 28 % ; group C 13 % ( chi 2 ; p = 0.057 for group A versus B and p < 0.005 for group A versus C ) . The incidence of silent pulmonary embolism ( PE ) ( new defect on V/Q scan ) was 28 % ( 8 out of 29 ) in patients with and 5 % ( 2 out of 43 ) in patients without DVT ( chi 2 ; p < 0.02 ) . The combination of high TAT and low anti-Xa activity on the 1st postoperative day identified a high risk group of patients who had a 56 % incidence of proximal DVT on the 8th to  
    Output:
    
AUTHORS ' CONCLUSIONS GCS are effective in diminishing the risk of DVT  in hospitalised patients , with strong evidence favouring their use in general and orthopaedic surgery .