EBM98.10.22::
65,,.Permanent Catheter,,.,,(arteriovenous graft).graft.
70,,(ballon angioplasty)(thrombectomy),..
. graftarteriovenous graft,.,???
AVG stenosisDialysis access:The most common cause of arteriovenous failure is thrombosis,which is most commonly secondary to progressive venous outflow stenosis followed by occlusion
5As of EBMAsk : ask an answerable questionAcquire : track down the best evidenceAppraisal : validity, impact, applicabilityApply : to patients problemAudit : effectiveness
Ask Patient:DM with nephropathy and progressed to ESRDHad arteriovenous graft created Intervention:any medicationComparison:placeboOutcome: arteriovenous graft thrombosis
Acquire
AcquirePubmed Main serch:Arteriovenous graftAntithrombosisAdvanced Search:randomised trials or meta-analysis
Acquire
AcquireallEBM reviewMain serch:Arteriovenousantithrombosis
AcquireAntiplatelet Agents Reduce Risks for Death, Stroke, Myocardial Infarction, Deep Venous Thrombosis, and Arterial OcclusionDouble-blind randomized trial of the effect of ticlopidine in arteriovenous fistulas for hemodialysisEffect of clopidogrel on early failure of arteriovenous fistulas for hemodialysis: a randomized controlled trialNo suitable paper for our PICO
Appraisal
AppraisalSelection criteria:RCTs of active drug versus placebo in patients with ESRD undergoing haemodialysis via an A-V fistula or prosthetic interposition AV graftlevel IAOutcome:measure analysed was the long-term fistula or graft patency rate
All randomised trials from electronic searches of MEDLINE (1966 to date), EMBASE (1980 to date) and CINAHL (1982 to date)
Characteristics of included studies
Andrassy 1974Crowther 2002Fiskerstrand 1984Grontoft 1985Grontoft 1998Harter 1979
Michie 1977Schmitz 2002Sreedhara 1994Trimarche 2006All randomised controlled studies
A (low risk of bias) B (moderate risk of bias) C(high risk of bias)
Quality of trials
Andrassy 1974
Aspirin 500mg VS placeboData base 92
Harter 1979
Aspirin 160 mg VS placeboData base 44
Crowther 2002Warfarin VS placeboData base 107
Fiskerstrand 1984Ticlopidine 250mg VS placeboData base 18
Grontoft 1985
Ticlopidine 250 mg VS placeboData base 42
Grontoft 1998
Ticlopidine 250mg VS placeboData base 254
Michie 1977
Sulfinpyrazone 200 mg VS placeboNo show data base
Schmitz 2002
fish oil VS placebo
Data base 24
Sreedhara 1994
1.Dipyridamole 75 mg +aspirin 325mg2.Dipyridamole 75mg3.Aspirin 325 mg4.placebo
Data base 108
Trimarche 2006
Clopidogrel VS placebo
Characteristics of excluded studies
Mata-analysis
Aspirin versus placebo
Cochran Q ( P < 0.1 )(Q/df) > 1
Reduce thrombosis by 58%Aspirin 500Aspirin 160Aspirin 325
Ticlopidine versus placebo
Cochran Q is not statistically significantBut (Q/df) > 1,Reduce thrombosis at one month by 53%All use ticlopidine 250 mg
Dipyridamole versus placebo
Dipyridamole + aspirin versus placebo
Warfarin versus placebo
Fish oil versus placebo
Clopidogrel versus placebo
NEJMN ENGL J MED 360;21 NEJM.ORG May 21, 2009
Method
Include > 18 y/oa new arteriovenous graft placed for the purpose of hemodialysisCurrently undergoing long-term hemodialysisExpected to undergo it within 6 months
Exclude Pregnant or breast-feedingIncreased risk of bleeding or a known bleeding disorderActive esophagitis, gastritis, or peptic ulcer diseasePlatelet count of less than 75,000Advanced liver disease; or required an anticoagulant or antiplatelet agent other than aspirinAllergy to aspirin or dipyridamole
Study Design and ProceduresRandomizationOne capsule contain 200 mg of extended-release dipyridamole plus 25 mg of immediate-release aspirinidentical-looking placebo Followed monthly by ultrasoundFrom July 31,2003~Jaunary 31,2008
RandomizationAccording to the center and access location(forearm or alternative site) with the use of a random permuted-block designPatients were unaware of the treatment assignments
Outcome Primary outcome:Loss of primary unassisted graft patency, defined as the first occurrence of graft thrombosis, an access procedure performed to correct a stenosis of 50% or more of the diameter of the adjacent normal vessel, or other surgical modification of the graft
OutcomeSecondary outcomes:Cumulative graft failureDeath from any causeCombined outcome of death from any cause
Statistical Analysis
Cox proportional-hazardsBasis:clinical centerAccess location (forearm or other site)Adjustmentserum albumin leveluse of ACEI of ARB
Statistical Analysis
Aimed to enroll 1056 patients for statistical powerprovide a statistical power of 85% to detect a 25% reduction in the incidence of the primary outcome, with a two-sided type I error rate of 5%.
Result
Study Population
Baseline Characteristics
Female,Black race And DM history
Efficacy
EfficacyPrimary unassisted patency at 1 year:23% VS 28%Median duration of patency:5.8 months VS 4.3 months
Hazard ratio
Secondary outcomeAll had no difference in the two group
Side effect
Side effectno significant difference between the two study groups with regard to any adverse-event category
Bias patient in this study,loss of graft patency in one year,higher than 54% originally predictedMay due to our study population;more woman,black race and DM historyMonthly follow up flow of graft,may increase the loss of graft patency incidence
Apply Aspirin or Ticlopidine or could decrease short term thrombosis;however There is no long term dataFish oil or Clopidogrel or Sulfinpyrazone could decrease decrease short term thrombosis;however data number was small and there is no long term dataWarfarin had no benefit
Suggestion Could use Aspirin(500mg or 160mg) or Ticlopidine(250mg) or dipyridamole (200mg)+aspirin (25mg) if patient has no bleeding tendency
Discussion If there is no obvious side effect,why not try antiplatelet?short term thrombosishemodialysis?