1801
Effect of anti-thrombotic medication on primary failure rate and survival of simple arteriovenous fistulae
A Murley, A Wijewardane , S Powers, C Allen, Lee Hollingsworth, J Baharani, T Wilmink
Institution: Departments of Renal Medicine and Vascular Surgery, Heart of England Foundation Trust, Birmingham, B95SS
Introduction:
Complications of dialysis access, including fistula thrombosis, are a common reason for patients with end stage renal failure to be admitted to hospital. Reducing the risk of fistula failure would improve patient's quality of life and improve dialysis outcomes. It has been suggested that use of antithrombotics (such as aspirin or warfarin), may reduce fistula primary failure rates and improve overall survival. The evidence so far is conflicting, some studies show benefit from antithrombotics, others no benefit and one study found increased complication rates (with no benefit) in patients taking antiplatelets. We were interested in how antithrombotic use affected outcomes in our local population. This study was performed with the aim of providing evidence (of benefit or harm) to clinicians considering whether to start patients on an antithrombotic before their fistula formation.
Materials and Methods: Retrospective review of two prospective databases of access operations and dialysis sessions of 720 patients from 2004 to 2011. Follow up until 1 March 2013. Patients with previous fistula operations excluded. Primary failure (PF) defined as an arteriovenous fistula (AVF) used for fewer than 6 consecutive dialysis sessions. Needling complications defined as failure to reach 6 consecutive sessions from when the fistula first used. AVF survival defined as date AVF abandoned. Antithrombotic medication was ascertained from case records from the preoperative vascular and renal clinic letters. Antithrombotic medication was not stopped prior to AVF formation.
Results: 720 patients were analysed: 47 excluded due to unknown outcomes and 2 non-standard fistulas removed. 372 (55%) patients were not on any antithrombotic medication, 203 (30%) were on aspirin, 24 (3.5%) on clopidogrel and 34 (5%) on warfarin. Antithrombotic medication had no significant effect on primary failure (p = 0.98), needling complications (p = 0.93) or AVF survival (log rank test, p = 0.98) nor was it a significant predictor of PF or AVF survival in a logistic regression model with proportional hazards adjusted for age, sex and type of AVF.
Conclusion: Antithrombotic medication has no significant effect on primary failure rate, complications causing interruption of dialysis or survival of AV fistulas. Although not from a randomised control trial our results suggest that antithrombotic use is not associated with improved fistula outcomes. Fistula formation alone should not be an indication to start a patient on an antithrombotic medication.