Duplex ultrasound surveillance after carotid artery endarterectomy.

OBJECTIVE: After carotid endarterectomy (CEA), patients have been regularly followed up by duplex ultrasound imaging. However, the evidence for long-term follow-up is not clear, especially if the results from an early duplex scan are normal. This study assessed and systematically reviewed the evidence base for long-term surveillance after CEA and a normal early scan. METHODS: Electronic databases were searched for studies assessing duplex surveillance after CEA in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome for this study was the incidence of restenosis after a normal early scan. The secondary outcome was the number of reinterventions after a normal early scan. RESULTS: The review included seven studies that reported 2317 procedures. Of those patients with a normal early scan, 2.8% (95% confidence interval, 0.7%-6%) developed a restenosis, and 0.4% (95% confidence interval, 0%-0.9%) underwent a reintervention for their restenosis during the follow-up period. CONCLUSIONS: This review confirms that routine postoperative duplex ultrasound surveillance after CEA is not necessary if the early duplex scan is normal.

Efficacy of the Ulnar-Basilic Arteriovenous Fistula for Hemodialysis: A Systematic Review.

BACKGROUND: The fistula first initiative has promoted arteriovenous fistulas (AVFs) as the vascular access of choice. To preserve as many future access options as possible, multiple guidelines advocate that the most distal AVF possible should be created in the first place. Generally, snuff box and radiocephalic (RC) are accepted and well-described sites for AVFs; however, the forearm ulnar-basilic (UB) AVF is seldom used or recommended. The aim of this study is to assess and systematically review the evidence base for the creation of the UB fistula and to critically appraise whether more attention should be given to this site. METHODS: Electronic databases were searched for studies involving the creation of UB fistulas for dialysis in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The primary outcomes for this study were 1-year primary and secondary patency rates. Secondary outcomes were rates of hemodialysis access-induced distal ischemia (HAIDI) and infection. RESULTS: After strict inclusion and/or exclusion criteria by 2 reviewers, 8 studies were included in our review. Weighted-pooled data reveal 1-year primary patency rate for UB AVFs of 53.0% (95% confidence interval [CI]: 40.1-65.8%) with a secondary patency rate of 72.0% (95% CI: 59.2-83.3). HAIDI and infection rates were low. CONCLUSIONS: Our review has shown that the UB AVF may be a viable alternative when a RC AVF is not possible, and dialysis is not required urgently. It has adequate 1-year primary and secondary patency rates and extremely low risk of HAIDI. While it may be more challenging for both surgeons and dialysis nurses to make it a successful vascular access it offers a further option of distal access which may be overlooked.

Arteriovenous fistula outcomes in the elderly.

OBJECTIVE: Over several decades, there has been an increase in the number of elderly patients requiring hemodialysis. These older patients typically have an increased incidence of comorbidities including diabetes, hypertension, and peripheral vascular disease. We undertook a systematic review of the current literature to assess outcomes of arteriovenous fistula (AVF) formation in the elderly and to compare the results of radiocephalic AVFs vs brachiocephalic AVFs in older patients. METHODS: A literature search was performed using MEDLINE, Embase, PubMed, and the Cochrane Library. All retrieved articles published before December 31, 2014 (and in English) primarily describing the creation of hemodialysis vascular access for elderly patients were considered for inclusion. We report pooled AVF patency rates and a comparison of radiocephalic vs brachiocephalic AVF patency rates using odds ratios (ORs). RESULTS: Of 199 relevant articles reviewed, 15 were deemed eligible for the review. The pooled 12-month primary and secondary AVF patency rates were 53.6% (95% confidence interval [CI], 47.3-59.9) and 71.6% (95% CI, 59.2-82.7), respectively. Comparison of radiocephalic vs brachiocephalic AVF patency rates demonstrated that radiocephalic AVFs have inferior primary (OR, 0.72; 95% CI, 0.55-0.93; P = .01) and secondary (OR, 0.76; 95% CI, 0.58-1.00; P = .05) patency rates. CONCLUSIONS: This meta-analysis confirms that adequate 12-month primary and secondary AVF patency rates can be achieved in elderly patients. Brachiocephalic AVFs have both superior primary and secondary patency rates at 12 months compared with radiocephalic AVFs. These important data can inform clinicians' and patients' decision-making about suitability of attempting AVF formation in older persons.

Is there a role of the kidney failure risk equation in optimizing timing of vascular access creation in pre-dialysis patients?

BACKGROUND: The aims of this study were to assess the utility of using the Kidney Failure Risk Equation (KFRE) as an indicator to guide timing of vascular access creation in pre-dialysis patients. MATERIALS AND METHODS: Patients referred for vascular access creation had KFRE calculated at the time of assessment and compared to standard criteria for referral. Receiver operating characteristic curves were produced for each parameter. The outcomes at 3 months, 6 months, and 1 year were used as time points for analysis. RESULTS: Two hundred and three patients were assessed, and full data sets were available on 190 (94.6%). Access was created in 156 patients (82.1%) with a fistula in 153 (98.7%). Only 65.7% initiated dialysis within the follow up period. Those patients with an AV access created (n = 156) 37 (23.7%) did not reach end stage over the entire follow up period. Of the remaining patients (n = 119) that reached end stage 72.2% (n = 86) started on an AVF/AVG and 27.7% (n = 33) on a CVC. Using ROC analysis for referral eGFR, ACR and KFRE predicting dialysis initiation predictors resulted in C statistics for eGFR, ACR, and KFRE2 of 0.68 (0.58-0.79), 0.75 (0.65-0.84), and 0.72 (0.62-0.81) at 3 months; 0.73 (0.65-0.81), 0.70 (0.62-0.78), and 0.75 (0.67-0.81) at 6 months; and 0.65 (0.57-0.72); 0.67 (0.59-0.75), and 0.68 (0.61-0.77) at 12 months. CONCLUSIONS: In a group of patients referred for vascular access creation the predictive models are relatively poor when applied to initiation of dialysis. The application of current guidelines to fistula creation appears to result in a high rate of unnecessary fistula formation and non-use. The study requires further evaluation in a test set of patients to confirm these findings and also identify where such risk based approaches may need modification.

WavelinQ created arteriovenous fistulas versus surgical radiocephalic arteriovenous fistulas? A single-centre observational study.

PURPOSE: Devices to permit percutaneous endovascular arteriovenous fistula formation have recently been introduced into clinical practice with promising initial evidence. As guidelines support a distal fistula first policy, the question of whether an endovascular arteriovenous fistula should be performed as an initial option is introduced. The aims of this study were to compare a matched cohort of endovascular arteriovenous fistula with surgical radiocephalic arteriovenous fistulas. MATERIALS AND METHODS: Using data from a prospectively collected database over a 3-year period, a matched comparative analysis was performed. RESULTS: WavelinQ arteriovenous fistulas (group W, n = 30) were compared with radiocephalic arteriovenous fistulas (group RC; n = 40). Procedural success was high with 96.7% for group W and 92.6% for group RC. Primary patency at 6 and 12 months was greater in group W (65.5% 6mo and 56.5% 12mo) compared to group RC (53.4% 6mo and 44% 12mo) (p = 0.69 and 0.63). Mean primary patency was significantly lower for RC (235 ± 210 days) vs W (362 ± 240 days) (p < 0.05). Secondary patency for group W was 75.8% and 69.5% at 6 and 12 months, respectively. Secondary patency for RC was lower at 66.7% and 57.6% at 6 and 12 months, respectively. CONCLUSION: Outcomes of WavelinQ arteriovenous fistulas in this series are similar to published results. When compared to a contemporaneously created group of surgical fistulas, WavelinQ demonstrated superior outcomes. These data would support that WavelinQ endovascular arteriovenous fistulas may be considered as a first option in the access pathway particularly if vessels at the wrist are absent or less than ideal.

Options for end stage vascular access: Translumbar catheter, arterial-arterial access or right atrial graft?

BACKGROUND: Running out of vascular access for dialysis is thankfully rare, but despite this, most units will have a number of patients with few options and in a precarious state. The increasing longevity of dialysis patients portends more patients will reach minimal access options. End stage vascular access is poorly defined but classification may enable assessment and comparison of treatment options. Three options for patients with end stage access are a central venous catheter through a translumbar or transhepatic route, arterial-arterial prosthetic loop or a right atrial graft. AIMS: The aims of this study are to provide a structured review of evidence for these procedures to allow application and guide practice for patients with end stage vascular access. METHODS: A standardised search of published literature was performed of relevant studies. In addition, the references cited in those papers were assessed for any further available articles. All study types were included and reviewed by two authors independently. Primary outcomes were patient survival and secondary patency rate at 3 and 12 months. Secondary outcomes were long-term patency rates, mean time to cannulation and complications such as access dysfunction, thrombosis and infection. SUMMARY: Based on the available evidence, it would appear that arterial-arterial prosthetic loop is a definitive option for maintaining dialysis access in patients with no more arteriovenous access options. Translumbar and transhepatic dialysis catheters may offer short- and medium-term options and right atrial grafts may also be suitable as an option where arterial-arterial prosthetic loop is unsuitable.

Early experience and observations in endovascular dialysis fistula re-intervention.

In recent years, new emerging technology has allowed the endovascular creation of dialysis fistulas in the proximal forearm without the need for open surgery. Two such systems currently exist, and evidence to date has demonstrated high rates of technical success in fistula creation, high rates of dialysis functionality, and low rates of re-intervention using both systems. Whilst early trial data has demonstrated lower rates of re-intervention to maintain patency compared to surgical fistulas, endovascular re-interventions are still required to maintain functionality. The endovascular fistula (endoAVF) typically exhibits a shared drainage pattern and is morphologically distinct from the surgical fistula and patterns of failure observed often differ to what has been traditionally encountered. A fresh approach and understanding is therefore required and here we share our observations and experience of endovascular re-intervention in endoAVF created with the Wavelinq system.

Quality improvement in vascular access: The role of patient-reported outcome measures.

Quality improvement initiatives should be aimed to enhance clinical outcomes, service delivery and quality of life for patients. For patients reliant on haemodialysis, vascular access is a lifeline. Survival differences relating to the type of vascular access are evident and many initiatives have focussed on increasing absolute rates of arteriovenous fistulas and/or decreasing central venous catheter use. While these have achieved some success quantitatively, the qualitative effects are less obvious. The aims of this review article are to explore the concepts of quality of care in vascular access. There is a paucity of studies into the effects of vascular access on the quality of life of dialysis patients, and where studies have been performed, generalised patient-reported outcome measures have been used. To facilitate the implementation of quality improvement programmes specifically for vascular access requires suitable tools. While existing patient-reported outcome measures may be applicable to vascular access, it is likely that these will require further evaluation, and the development of vascular access-specific patient-reported outcome measures may be required.

Arteriovenous fistula creation in a patient without a pulse: Vascular access in patients with left ventricular assist devices.

Left ventricular assist devices are used in heart failure patients as bridge to transplantation or increasingly as a destination therapy. These patients frequently have renal dysfunction and many reach end-stage renal failure. If haemodialysis is required, minimization of infection risk is essential. Arteriovenous grafts have been recommended for these patients due to hypothetical concerns regarding fistula maturation due to continuous flow. A case is described where a brachiocephalic arteriovenous fistula was successfully formed and used for dialysis without issue. This is one case of a small number in the literature where arteriovenous fistulas have been used in left ventricular assist device patients and it appears that concerns are unfounded and good outcomes have been reported. It would appear from this experience that approaches to vascular access for dialysis in patients with continuous-flow left ventricular assist devices are in accordance with vascular access guidelines and standard practice.

Prospective Audit to Study urokinaSe use to restore Patency in Occluded centRal venous caTheters (PASSPORT 1).

OBJECTIVES: Tunnelled central venous catheters dysfunction can be defined as failure to provide blood flow above 200 mL/min during dialysis often caused by thrombosis. Although urokinase is used routinely for thrombolysis, there is wide variation in dose regimens. A multidisciplinary group was formed to address this issue and offer guidance. METHODS: Dialysis centres that used urokinase in the United Kingdom took part in a prospective study to determine the safety and outcomes of thrombolysis using agreed protocols. Data were collected anonymously from September 2017 until February 2018. Catheter blood flow was measured before and after the following interventions: catheter dwell or push locks with 12,500-50,000 IU or catheter infusion with 100,000-250,000 IU of urokinase. Interventions were repeated if the blood flow remained below 200 mL/min. RESULTS: 10 centres took part and recruited 200 patients; 45.5% were female and 54.5% were male with mean age of 63.6 (±15.2) years. The cumulative success rate for thrombolysis was 90.5% after first intervention, 97% after second intervention, and 99% after more than 2 interventions. Although there was trend towards benefit with dose increments, the success rate between push/dwell locks and high-dose infusion of urokinase was not significantly different (p = 0.069). Seventeen (8.5%) tunnelled central venous catheters were removed due to failure of treatment. No urokinase-related adverse events were reported. CONCLUSION: In this study, urokinase was safe and efficacious; there was no difference between dwell and push locks. There was some benefit with high-dose infusion of urokinase compared to the dwell and push lock.

End-stage vascular access failure: can we define and can we classify?

BACKGROUND: Renal replacement therapy using dialysis has evolved dramatically over recent years with an improvement in patient survival. With this increased longevity, a cohort of patients are in the precarious position of having exhausted the standard routes of vascular access. The extent of this problem of failed access or 'desperate measures' access is difficult to determine, as there are no uniform definitions or classification allowing standardization and few studies have been performed. The aim of this study is to propose a classification of end-stage vascular access (VA) failure and subsequently test its applicability in a dialysis population. METHODS: Using anatomical stratification, a simple hierarchical classification is proposed. This has been applied to a large dialysis population and in particular to patients referred to the complex access clinic dedicated to patients identified as having exhausted standard VA options and also those dialysing on permanent central venous catheters (CVC). RESULTS: A simple classification is proposed based on a progressive anatomical grading of (I) standard upper arm options exhausted, (II) femoral options exhausted and (III) other options exhausted. These are further subdivided anatomically to allow ease of classification. When applied to a complex group of patients (n = 145) referred to a dedicated complex access clinic, 21 patients were Class I, 26 Class II and 2 Class III. Ninety-six patients did not fall into the classification despite being referred as permanent CVC. CONCLUSIONS: The numbers of patients who have exhausted definitive access options will continue to increase. This simple classification allows the scope of the problem and proposed solutions to be identified. Furthermore, these solutions can be studied and treatments compared in a standardized fashion. The classification may also be applied if patients have the option of transplantation where iliac vessel preservation is desirable and prioritization policies may be instituted.