***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: Development of dialysis therapy over the last decade caused considerable increase in the number of patients receiving haemodialyses as kidney substitution therapy . However , a wider use result ed in greater number of A-V fistula complications .  Uraemia patients were reported to develop plasmatic and platelet haemostasis disorders which provoke dialysis fistula thrombosis . The aim of the paper was to answer how Ticlopidine affected decrease in the number of late thrombosis complications in freshly created A-V fistula . The study included 60 patients , 30 of whom were given Ticlopidine ( 125 mg twice every 24h ) . The other 30 patients constituted the  control group and did not received the drug . The follow-up lasted 27 months . It was concluded that preventive administration of Ticlopidine significantly reduces the extent of late thrombosis complications Background The Dialysis Access Consortium ( DAC ) was developed to investigate interventions to improve hemodialysis vascular access outcomes . The autogenous arteriovenous fistula created by direct connection of native artery to vein is the recommended vascular access for hemodialysis . However , it fails frequently due to clotting after surgery . Purpose The DAC Early AV Fistula Thrombosis Trial tests the hypothesis that clopidogrel can prevent early fistula failure and increase the number of fistulas that ultimately become usable for hemodialysis access . This is one of two initial and concurrent trials being performed by the DAC . The companion trial investigates pharmacologic approaches to prevent venous stenosis leading to AV graft failure . Methods This is a multicenter , r and omized , double-blind , placebo-controlled trial that will enroll 1284 patients over four years . Patients undergoing creation of a new native arteriovenous ( AV ) fistula are r and omized to treatment with clopidogrel or placebo for six weeks following fistula creation surgery . The primary outcome is fistula patency at six weeks . The major secondary outcome is fistula suitability for dialysis . Results This paper examines key aspects of this study that have broad relevance to trial design including : 1 ) the selection of an intermediate event as the primary outcome , 2 ) timing of the intervention to balance efficacy and safety concerns , 3 ) ethical considerations arising from required modifications of concomitant drug therapy , and 4 ) choosing an efficacy or effectiveness evaluation of the intervention . Conclusions This is the first , large , multicenter trial evaluating a pharmacologic approach to prevent early AV fistula failure and promote more usable fistulas for hemodialysis . The method ologic challenges identified and addressed during the development of this trial should help to inform the design of future vascular access trials , and are relevant to clinical trials addressing a wide range of questions Previous studies demonstrated a high incidence of local thrombosis in patients in whom external arteriovenous shunts were used for vascular access . This procedure provides , therefore , a useful model for the evaluation of potential antithrombotic agents . The effect of the hemorheologically and hemostasiologically active drug Pentoxifylline on the incidence of thrombosis of arteriovenous shunts ( Ramires shunt ) was investigated in a long-term , double-blind , placebo-controlled study in 51 patients on chronic hemodialysis . The two treatment groups were comparable in age , sex , concomitant medication , and dialysis program ( three times per week for four hours ) . Drugs known to affect platelet function or coagulation were excluded , with the exception of heparin , during the dialysis procedure . All shunts were placed in the forearm and inserted into the distal part of the radial artery and basilic antebrachial vein . Simultaneously , for medical reasons , in all patients an arteriovenous fistula was performed ( proximal part of radial artery and cephalic antebrachial vein ) . Shunt thrombosis was assumed when the flow in the shunt discontinued under visual and auscultatory control . Thrombi were documented by physical removal from the arterial part of the shunt by use of gentle suction or by complete shunt thrombosis ( both arterial and venous part of the shunt ) . Thereafter , the patients ' trial period terminated . The total number of thrombi during the observation period was 44 in the pentoxifylline group ( 26 patients ) , compared with 82 in the placebo group ( 25 patients ) . The mean number of thrombi per patient was 1.69±1.29 in the pentoxifylline group , significantly lower than that in the placebo group ( 3.28±1.99 / p < 0.05 ) . Further , the periods until the occurrence of first thrombosis ( in the arterial part of the shunt ) and complete shunt thrombosis were assessed per patient in days : in the pentoxifylline group the first shunt thrombosis occurred after 34.8±6.7 days ( x±s.e . ) and with placebo after 16.7±4.4 days ( p < 0.05 ) . The complete thrombosis was recorded in the pentoxifylline group after 46.8±6.5 days and with placebo after 24.6±5.8 days ( p < 0.05 ) . These findings indicate that pentoxifylline medication markedly reduced the incidence of thrombosis of arteriovenous shunt and distinctly extended the shunt survival period , suggesting an effective antithrombotic property of the drug The effect of sulfinpyrazone on the incidence of thrombosis of arterio-venous shunts was investigated in a double-blind crossover study in 45 patients on chronic hemodialysis over a period of 12 months . The incidence of thrombosis was reduced from 0.64 thrombi per patient month when on placebo to 0.21 thrombi per patient month when on sulfinpryazone ( P < 0.001 ) . The therapeutic effect was more striking in men than in women and became evident within a week of starting the drug . The side effects were minimal , requiring withdrawal from the study of only one patient . This crossover study strengthens the findings in the previous report that sulfinpyrazone is of value in the prevention of thrombosis Since platelet cyclo-oxygenase is much more sensitive to inactivation by aspirin than is the enzyme in the arterial wall and low doses of aspirin may prevent thrombosis by blocking thromboxane synthesis , we conducted a r and omized , double-blind trial of aspirin ( 160 mg per day ) vs. placebo in 44 patients on chronic hemodialysis . The study was continued until there were 24 patients with thrombi and both groups had been under observation for a mean of nearly five months . Thrombi occurred in 18 of 25 ( 72 per cent ) of patients given placebo and 16 of 19 ( 32 per cent ) of those given aspirin ( P less than 0.01 ) . The incidence of thrombosis was reduced from 0.46 thrombi per patient month in the placebo group to 0.16 thrombi per patient month in the aspirin group ( p less than 0.005 ) . A dose of 160 mg of aspirin per day is an effective , nontoxic antithrombotic regimen in patients on hemodialysis Since fish oil has been reported to reduce platelet aggregability , to reduce blood viscosity by increasing red blood cell deformability and to lower blood pressure , we studied the effect of dietary supplementation with fish oil on the occurrence of adverse effects in patients receiving recombinant human erythropoietin ( rHuEPO ) .  In a prospect i ve , r and omized , double blind cross-over design we studied the effect of daily ingestion of 3 g fish oil versus 3 g corn oil ( placebo ) for 5 months , with a wash-out period of 3 months in between . Thirty-two dialysis patients newly treated with rHuEPO participated . rHuEP0 was given using a low and slow dose regimen ( 25 U/kg twice weekly s.c . ) . Target Hct was 35 % . Blood pressure , red blood cell deformability , plasma viscosity , fatty acid composition of plasma phospholipids , and fibrinogen levels were measured at 0 , 5 , 8 and 13 months . In both groups a stable target Hct ( 35 % ) was reached within 3 months . Blood pressure was not significantly different between the groups at any time point . In 4 patients ( 2 on fish oil and 2 on placebo ) antihypertensives had to be increased to regulate blood pressure adequately , whereas shunt occlusion occurred in one patient on placebo . Despite a significant increase in the omega-3 fatty acid content of plasma phospholipids during ingestion of fish oil , no significant changes in red blood cell deformability were observed . Since hypertension and shunt occlusion occurred at rates comparable to those reported in the literature , long-term ingestion of fish oil does not appear to mitigate the side effects of low and slow dose rHuEPO When constructing arteriovenous fistulas for haemodialysis in chronic renal failure patients , one of the main problems is still their clotting tendency . Ticlopidine is an effective inhibitor of platelet aggregation . In this r and omized double-blind study placebo or ticlopidine 250 mg twice daily was given to chronic uremic patients up to 4 weeks after construction of an arteriovenous fistula . 42 patients were recruited and 36 completed the trial . The fistula clotted in 8 patients on placebo and in 2 patients on ticlopidine . The difference is significant . This effect was achieved without an increased frequency of side effects compared with placebo . It is concluded that ticlopidine has a function as a thromboprophylactic drug in chronic uremic patients Background : The most common complication of hemodialysis ( HD ) access graft is thrombosis . Clopidogrel , an inhibitor of platelet aggregation , was assessed to prevent this serious complication . Methods : A prospect i ve study in which 24 patients on chronic HD whose vascular accesses were grafts were divided into two groups : group A ( n = 12 , 50 % ) consisted of patients who did not receive antithrombotic therapy after graft creation , and group B ( n = 12 , 50 % ) received clopidogrel 75 mg/day from 2 days after surgery onwards . Both groups were not different according to age , gender , cause of renal failure , hematocrit levels , platelet counts and Kt/V. All patients ’ thrombotic episodes were followed up from the day of graft surgery until thrombosis was diagnosed . Finally , the patient survival difference between both groups was determined . Results : Eleven thrombotic episodes were diagnosed in group A while one event was reported in group B ( p < 0.001 ) . Graft access days of patency were significantly longer in group B compared to group A ( 380.8 ± 170 vs. 90.1 ± 57.2 , p < 0.001 ) . Time that elapsed from dialysis initiation to graft creation was not different ( group A 18 ± 12 days , group B 20 ± 10 days ) . Days on HD were different between both groups ( group A 208.9 ± 97.2 vs. group B 583.2 ± 287.0 , p < 0.001 ) and all patients from group A ( n = 12 , 100 % ) and 2 patients from group B ( 16.7 % ) died ( p = 0.001 ) . Major bleeding events were not reported . Conclusions : Clopidogrel significantly decreased thrombotic graft episodes . Patients on clopidogrel had a prolonged vascular access patency , longer time on HD and better survival Vascular access malfunction , usually presenting with an inadequate access flow ( Qa ) , is the leading cause of morbidity and hospitalization in hemodialysis ( HD ) patients . Many methods of thermal therapy have been tried for improving Qa but with limited effects . This r and omized trial was design ed to evaluate the effect of far-infrared ( FIR ) therapy on access flow and patency of the native arteriovenous fistula ( AVF ) . A total of 145 HD patients were enrolled with 73 in the control group and 72 in the FIR group . A WS TY101 FIR emitter was used for 40 min , and hemodynamic parameters were measured by the Transonic HD(02 ) monitor during HD . The Qa(1)/Qa(2 ) and Qa(3)/Qa(4 ) were defined as the Qa measured at the beginning/at 40 min later in the HD session before the initiation and at the end of the study , respectively . The incremental change of Qa in the single HD session with FIR therapy was significantly higher than that without FIR therapy ( 13.2 + /- 114.7 versus -33.4 + /- 132.3 ml/min ; P = 0.021 ) . In comparison with control subjects , patients who received FIR therapy for 1 yr had ( 1 ) a lower incidence ( 12.5 versus 30.1 % ; P < 0.01 ) and relative incidence ( one episode per 67.7 versus one episode per 26.7 patient-months ; P = 0.03 ) of AVF malfunction ; ( 2 ) higher values of the following parameters , including Delta(Qa(4 ) - Qa(3 ) ) ( 36.2 + /- 82.4 versus -12.7 + /- 153.6 ml/min ; P = 0.027 ) , Delta(Qa(3 ) - Qa(1 ) ) ( 36.3 + /- 166.2 versus -51.7 + /- 283.1 ml/min ; P = 
    Output:
    
The meta-analyses of three studies for ticlopidine ( an anti-platelet treatment ) , which all used the same dose of treatment but with a short follow-up of only one month , suggest ticlopidine may have a beneficial effect as an adjuvant treatment to increase the patency of AV fistulae and grafts in the short term .
There was insufficient evidence to determine if there was a difference in graft patency between placebo and other treatments such as aspirin , fish oil , clopidogrel , PRT-201 , dipyridamole , dipyridamole plus aspirin , warfarin , and sulphinpyrazone .