Key messages
• There was insufficient evidence to suggest that a specific intervention was better than another for the outcomes of failure, function at 30 days, technical success and adverse events (both major and minor).
• Function at 30 days may improve with surgical compared to mechanical thrombectomy; however, the evidence is very uncertain.
• Death, access dysfunction, successful dialysis, and SONG (Standardised Outcomes in Nephrology) outcomes were rarely reported.
Why is it important to treat thrombosed (clotted) haemodialysis access?
When kidneys no longer work properly, dialysis (a process for cleaning the blood) is required. To connect to a dialysis machine, access is required via an entry point to the blood. An arteriovenous fistula (AVF) or arteriovenous graft (AVG) is a connection between an artery and a vein, and is used as this access point. If a blood clot forms, it may reduce the blood flow through this access.
What did we want to find out?
We wanted to find out what is the best method for treating clots in haemodialysis AVF or AVG.
What did we do?
We searched for randomised trials that looked at interventions used for treating thrombosed dialysis access. We compared and summarised the results of the trials and rated our confidence in the information based on factors such as trial methods and size.
What did we find?
We included 14 studies randomising 1176 people with thrombosed haemodialysis access. We included three types of interventions for the treatment of thrombosed AVF and AVG: (1) types of thrombectomy (thrombus removal), (2) types of thrombolysis (thrombus dissolution) and (3) surgical procedures. Most of the included studies had poor study design, low numbers of patients, and some had pharmaceutical industry funding. The surgical procedure in thrombosed AVF may be associated with better results at 30 days. There is insufficient evidence to suggest that a specific intervention is better to ensure adequate dialysis. There is insufficient evidence of which interventions have a lower risk of complications.
What are the limitations of the evidence?
The small number of studies per comparison and the small size of the studies were limitations in this review. Not all the studies provided data about the outcomes we were interested in. We are unsure about the results.
How up-to-date is the evidence?
The evidence is up to date as of January 2024.
It remains unclear whether any intervention therapy affects the patency at 30 days or failure in any thrombosed HD AV access (very low certainty of evidence). Future research will very likely change the evidence base. Based on the importance of HD access to these patients, future studies of these interventions among people receiving HD should be a priority.
Patients who present with problems with definitive dialysis access (arteriovenous fistula (AVF) or arteriovenous graft (AVG)) become catheter dependent (temporary access), a condition that often carries a higher risk of infections, central venous occlusions and recurrent hospitalisations. For AVG, primary patency rates are reported to be 30% to 90% in patients undergoing thrombectomy or thrombolysis. According to the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines, surgery is preferred when the cause of the thrombosis is a stenosis at the site of the anastomosis in thrombosed AVF. The European Best Practice Guidelines (EBPG) reported that thrombosed AVF may be preferably treated with endovascular techniques, but when the cause of thrombosis is in the anastomosis, surgery provides better results with re-anastomosis. Therefore, there is a need to carry out a systematic review to determine the effectiveness and safety of the intervention for thrombosed fistulae.
This review aims to establish the efficacy and safety of interventions for failed AVF and AVG in patients receiving haemodialysis (HD).
We searched the Cochrane Kidney and Transplant Register of Studies up to 28 January 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, EMBASE, conference proceedings, the International Clinical Trials Registry Portal (ICTRP) Search Portal and ClinicalTrials.gov.
The review included randomised controlled trials (RCTs) and quasi-RCTs in people undergoing HD treatment using AVF or AVG presenting with clinical or haemodynamic evidence of thrombosis. Patients had to have used an AVF or AVG at least once.
Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
Our search strategy identified 14 eligible studies (1176 randomised participants) for inclusion in this review. We included three types of interventions for the treatment of thrombosed AVF and AVG: (1) types of thrombectomy, (2) types of thrombolysis and (3) surgical procedures. Most of the included studies had a high risk of bias due to a poor study design, a low number of patients and industry involvement. Overall, there was insufficient evidence to suggest that a specific intervention was better than another for the outcomes of failure, primary patency at 30 days, technical success and adverse events (both major and minor). Primary patency at 30 days may improve with surgical compared to mechanical thrombectomy (3 studies, 404 participants: RR 1.36, 95% CI 1.07 to 1.67); however, the evidence is very uncertain. Death, access dysfunction, successful dialysis, and SONG (Standards Outcomes in Nephrology) outcomes were rarely reported. The current review is limited by the small number of available studies with a limited number of patients enrolled. Most of the studies included in this review have a high risk of bias and a low or very low certainty of evidence. Further research is required to define the most effective and clinically appropriate technique for access dysfunction.