Surgery versus Interventional Radiology in the Management of Thrombosed Vascular Access for Hemodialysis

Patency Rates After Successful Arteriovenous Fistula Thrombectomy: Relevance of the Flow/d-Dimer Ratio in the Decision-Making

OBJECTIVES

Surgical thrombectomy for acute arteriovenous fistula (AVF) thrombosis is one of the primary salvage intervention. The independent risk factors affecting the patency of AVF after a successful thrombectomy are yet unknown. Here, the author aimed to report the results of surgically corrected AVFs and the independent risk factors which may cause early failure following the surgical salvage.

METHODS

The study cohort comprised 24 patients who had acute AVF thrombosis and underwent successful surgical thrombectomy in the first 24 to 48 hours between January 2016 and April 2020 in our center. The study group was divided into patients with recurrent AVF thrombosis (n = 11, 45.8%) and without recurrent AVF thrombosis (n = 13, 54.1%) following surgical thrombectomy with a follow-up of 22.4 ± 6.8 months. Postthrombectomy primary and secondary patency of AVF were also evaluated.

RESULTS

The mean age of the cohort was 58.1 ± 15.2 years. A simple thrombectomy was performed for all cases. Only 2 cases have required a revision at the anastomosis due to severe intimal hyperplasia. Postthrombectomy primary patency rate was 45.5% for 18 months. Receiver operating characteristic analysis was performed with a resulting area under the curve value of 0.81 (95% CI: 0.35-0.94, P = .006) for flow (mL)/d-dimer (ng/mL) <0.63 in predicting recurrent AVF thrombosis following surgical thrombectomy.

CONCLUSIONS

Flow (mL)/d-dimer (ng/mL) <0.63 was independent predictor of recurrent thrombosis (RT) of a surgically salvaged AVF. The patients at risk for RT or who may benefit from further intervention should be identified with predictive parameters.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Restoration of Autologous Arteriovenous Fistula by Removal of the Occluded Short Venous Part and Venovenous End-To-End Anastomosis in a Hemodialysis Patient

Standard salvage procedures for occuluded autologous arteriovenous fistula (AVF) in a hemodialysis patient are endovascular and/or surgical therapy. When endovascular therapy and thrombectomy prove unsuccessful, it is most likely that creating a new AVF or arteriovenous graft will be considered. However, if the occuluded venous part is short, we have adopted an operative technique for repair of AVF by removal of the occluded short venous part and venovenous end-to-end anastomosis. To our knowledge, the efficacy and clinical course of restoration of AVF by the technique have not been reported to date. Here, we describe the technique and report the successful treatment of a hemodialysis patient who developed AVF occlusion.

Clinical effectiveness of open thrombectomy for thrombosed autogenous arteriovenous fistulas and grafts

OBJECTIVE

Arteriovenous (AV) fistulas are the preferred hemodialysis access for patients with end-stage renal disease, although multiple interventions are typically needed to maintain patency. When AV fistulas thrombose, however, there is debate as to whether open thrombectomy should be attempted, particularly for salvage of upper arm fistulas. This study was designed to evaluate outcomes after open thrombectomy of upper arm and forearm AV fistulas compared with AV grafts.

METHODS

We identified all patients who underwent an open thrombectomy procedure for a thrombosed AV fistula or graft at a single academic medical center between January 2006 and March 2017. The specific type of AV fistula or graft was evaluated, as were the patients' demographics, comorbidities, medications, adjunctive procedures during thrombectomy, and secondary interventions. The primary outcome measures, postintervention primary patency and postintervention secondary patency, were analyzed using Kaplan-Meier curves and Cox regression models for risk adjustment.

RESULTS

During the study period, 209 open thrombectomy procedures were performed in 139 patients; 73 (35%) were undertaken in AV fistulas and 136 (65%) in grafts. Patients with upper arm fistulas (n = 52; 54% brachiocephalic, 46% brachiobasilic) and forearm fistulas (n = 16) were more likely to be male but less likely to have cerebrovascular disease or ischemic heart disease and to be receiving anticoagulation therapy compared with graft patients. After thrombectomy, the majority of patients underwent dialysis successfully (70% upper arm fistulas, 56% forearm fistulas, 63% grafts; P > .05), and 1-year survival rates were similar in all three cohorts. Postintervention primary patency at 1 year was significantly higher for AV fistulas vs grafts (33% for upper arm fistulas and 25% for forearm fistulas vs 9% for grafts; P < .05), which was confirmed in multivariate analysis, where upper arm AV fistulas had a 46% lower risk of recurrent thrombosis or secondary intervention (hazard ratio, 0.56; 95% confidence interval, 0.35-0.85; P < .05). Postintervention secondary patency at 1 year was similar between AV fistulas and grafts (44% for upper arm fistulas vs 43% for forearm fistulas vs 31% for grafts; P = .16), but in multivariate analysis, upper arm fistulas were significantly less likely to fail (hazard ratio, 0.63; 95% confidence interval, 0.40-1.00; P = .05).

CONCLUSIONS

Our data suggest that AV fistula thrombectomy is successful in up to 70% of cases, with significantly improved risk-adjusted 1-year primary and secondary patency rates for upper arm fistulas compared with grafts. Whereas the risk of access failure is high after thrombectomy, efforts to salvage upper arm AV fistulas are effective in most patients and should be undertaken when feasible.

A novel technique for duplex-guided office-based interventions for patients with acute arteriovenous fistula occlusion

OBJECTIVE

The purpose of the study was to aggressively salvage acutely occluded arteriovenous fistulas (AVFs) using duplex imaging as the sole imaging modality for percutaneous transluminal angioplasty of acutely thrombosed AVF.

METHODS

Over a period of 12 months, 14 patients with acute thrombosis of their AVFs underwent 18 procedures in a single center for AVF salvage. All 14 patients presented with chronic renal failure, and six were diabetic. All patients were treated under duplex guidance alone. Treatment included simple balloon dilation and maceration (group A; n =10 procedures [56%]) for subacute thrombosis or pharmacomechanical thrombectomy (group B; n = 8 procedures [44%]) for more hypoechoic thrombus. A successful procedure was defined as immediate restoration of flow through the AVF.

RESULTS

Of the 18 procedures, 13 (72%) were successful. Of the 14 patients, thrombus was located at the perianastomotic AVF in 6 (43%), proximal-mid AVF in 6 (43%), mid AVF in 1 (7%), and distal AVF in 1 (7%). From group A, six (60%) were successful. From group B, seven (88%) were successful. Among the unsuccessful procedures, one group B patient was hypercoagulable (polycythemia vera). Of the 18 procedures, 16 (89%) were treated within 2 weeks from when duplex revealed the presence of thrombus. Early rethrombosis (<1-month patency) occurred in three cases (17%), and these patients received new fistulas. Full restoration of the fistula flow was established in 14 cases (78%). Of these 14 patients, 8 (57%) are currently on hemodialysis via fistula, 3 patients (21%) had newly placed fistulas after failed interventions, 2 patients (14%) are not on dialysis yet, and 1 patient (7%) with polycythemia vera disorder is on dialysis via a Tesio catheter (MedComp, Harleysville, Pa).

CONCLUSIONS

The sole use of duplex ultrasound imaging to salvage acutely occluded AVFs using percutaneous transluminal angioplasty is a safe and effective alternative to traditional treatment of thrombosed failing/maturing AVF.

Surgical versus endovascular management of thrombosed autogenous arteriovenous fistulae

A best evidence topic in vascular surgery was written according to a structured protocol. The question addressed was: In patients undergoing haemodialysis with thrombosed autogenous arteriovenous fistulae, does surgical management as compared to endovascular management improve clinical outcomes? A total of 130 papers were identified using the search protocol described, of which four represented the best evidence available to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Three of the four studies demonstrated no significant difference between the initial success rates of surgical or endovascular management. However, one study illustrated that hybrid surgery (a combination of endovascular and surgical techniques) significantly improved initial success rates, shortened hospital stays and decreased total monetary costs. Furthermore, three studies showed that subsequent fistula patency rates were significantly higher when surgical management was instigated. Nevertheless, one study suggested that surgery worsened subsequent patency rates and that in fact surgical patients were more likely to require temporary dialysis catheters than endovascular patients. Therefore, the clinical bottom line is that with careful patient and fistula selection, surgery provides a number of benefits over endovascular management of thrombosed autogenous arteriovenous fistulae, particularly in the medium to long term. However, further appropriately powered and randomised Level 1 studies are necessary to clarifying this important issue.