Emma Aitken

Effect of regional versus local anaesthesia on outcome after arteriovenous fistula creation: a randomised controlled trial

BACKGROUND Arteriovenous fistulae are the optimum form of vascular access in end-stage renal failure. However, they have a high early failure rate. Regional compared with local anaesthesia results in greater vasodilatation and increases short-term blood flow. This study investigated whether regional compared with local anaesthesia improved medium-term arteriovenous fistula patency. METHODS This observer-blinded, randomised controlled trial was done at three university hospitals in Glasgow, UK. Adults undergoing primary radiocephalic or brachiocephalic arteriovenous fistula creation were randomly assigned (1:1; in blocks of eight) using a computer-generated allocation system to receive either local anaesthesia (0·5% L-bupivacaine and 1% lidocaine injected subcutaneously) or regional (brachial plexus block [BPB]) anaesthesia (0·5% L-bupivacaine and 1·5% lidocaine with epinephrine). Patients were excluded if they were coagulopathic, had no suitable vessels, or had a previous failed ipsilateral fistula. The primary endpoint was arteriovenous fistula patency at 3 months. We analysed the data on an intention-to-treat basis. This study was registered with ClinicalTrials.gov (NCT01706354) and is complete. FINDINGS Between Feb 6, 2013, and Dec 4, 2015, 163 patients were assessed for eligibility and 126 patients were randomly assigned to local anaesthesia (n=63) or BPB (n=63). All patients completed follow-up on an intention-to-treat basis. Primary patency at 3 months was higher in the BPB group than the local anaesthesia group (53 [84%] of 63 patients vs 39 [62%] of 63; odds ratio [OR] 3·3 [95% CI 1·4-7·6], p=0·005) and was greater in radiocephalic fistulae (20 [77%] of 26 patients vs 12 [48%] of 25; OR 3·6 [1·4-3·6], p=0·03). There were no significant adverse events related to the procedure. INTERPRETATION Compared with local anaesthesia, BPB significantly improved 3 month primary patency rates for arteriovenous fistulae. FUNDING Regional Anaesthesia UK, Darlindas Charity for Renal Research.

Early cannulation prosthetic graft (Acuseal) for arteriovenous access: a useful option to provide a personal vascular access solution.

Purpose Early cannulation arteriovenous grafts (ecAVGs), such as the GORE® Acuseal™, have “low bleed” properties permitting cannulation within 24 hours of insertion. They may provide an alternative to tunneled central venous catheters (and associated line complications) in patients requiring urgent vascular access. Methods We present our early experience of 37 patients treated with the GORE® Acuseal™ ecAVG. Results A total of 11 upper limb, 24 lower limb and 2 complex graft procedures were performed. Indications for ecAVG were as follows: bridge to transplantation (21.6%); bridge to arteriovenous fistula (AVF) maturation (8.1%); AVF salvage (8.1%); no native options (67.6%, including 17 patients with bilateral central vein stenosis); 36 AVGs (97.3%) were successfully cannulated. Mean time to first cannulation: 30.4±23.4 hours (range: 2–192). Primary and secondary patency rates at 3, 6 and 12 months were 64.9%, 48.6%, 32.4% and 70.2%, 59.4%, 40.5% respectively. The systemic bacteremia rate was 0.2 per 1,000 access days. There was one perioperative death. Other complications included hematoma at cannulation sites (n=9), pseudoaneurysm (n=3) and local infection at graft site (n=6). A total of 26 of 37 patients (70.6%) achieved a “personal vascular access solution”: bridge to transplantation (n=8), bridge to functioning AVF/interposition AVG (n=5), maintenance hemodialysis via ecAVG (n=13); death with functioning AVG (n=1). Conclusions Early experience with the GORE® Acuseal™ is encouraging. Patency and bacteremia rates are at least comparable to standard polytetrafluoroethylene grafts. ecAVGs have permitted cannulation within 24 hours of insertion and line avoidance in the majority of patients. Nearly three-quarters of patients achieved a definitive “personal vascular access solution” from their ecAVG.

Outcomes following renal transplantation in older people: a retrospective cohort study

BackgroundThe mean age of renal transplant recipients is rising, with age no longer considered a contraindication. Outcomes in older patients have not, however, been fully defined. The aim of our study is to evaluate outcomes in older people following renal transplantation at a Scottish regional transplant unit.MethodsAll renal transplants from January 2001 to December 2010 were analysed (n = 762). Outcomes following renal transplantation in people over 65 years old were compared to those in younger patients. Outcome measures were: delayed graft function (DGF), primary non-function (PNF), biopsy proven acute rejection (BPAR), serum creatinine at 1 year and graft and recipient survival. Lengths of initial hospital stay and re-admission rates were also assessed. Student’s T-Test was used to analyse continuous variables, Pearson’s Chi-Squared test for categorical variables and the Kaplan-Meier estimator for survival analysis.ResultsOlder recipients received proportionately more kidneys from older donors (27.1% vs. 6.3%; p  <  0.001). Such kidneys were more likely to have DGF (40.7% vs. 16.9%; p < 0.001). Graft loss at 1 year was higher in kidneys from older donors (15.3% vs. 7.6%; p = 0.04). There was no significant difference in patient survival at 1 year based on the age of the donor kidney. Recipient age did not affect DGF (16.9% vs. 18.5%; p = 0.77) or graft loss at 1 year (11.9% vs. 7.8%; p = 0.28). Older recipients were, however, more likely to die in the first year post transplant (6.8% vs. 2.1%; p = 0.03). BPAR was less common in older patients (6.8% vs. 22%; p < 0.01). Older recipients were more likely to be readmitted to hospital (31.8% vs. 10.9%; p < 0.001).ConclusionsOlder patients experience good outcomes following renal transplantation and donor or recipient age alone should not preclude this treatment. An awareness of this in clinicians managing older patients is important since the prevalence of End Stage Renal Disease is increasing in this age group.

Cardiovascular changes occurring with occlusion of a mature arteriovenous fistula

Background The aim of this study was to evaluate the relationship between Qa, cardiovascular parameters and symptomatic cardiac disease. Methods A prospective cohort study of 100 patients dialysing via an arteriovenous fistula (AVF) was performed. Qa was measured using pulsed Doppler ultrasound. Cardiovascular parameters were measured using thoracic bioimpedance technique (Medis, GmbH). Measurement of cardiovascular parameters was undertaken pre- and post-occlusion of the AVF. Results Mean age was 57.1 years (range: 19-83); 51% male. Mean values pre-occlusion: mean arterial blood pressure (MABP) 89.6 ± 16.9 mmHg; stroke volume index (SVI) 39.3 ± 4.6 mL; cardiac index (CI) 3.7 ± 0.8 L/min/m2; systemic vascular resistance index (SVRI) 585.5 ± 67.8 dyn/sec/cm−5/m2; oxygen delivery (DO2I) 607.1 ± 116.8 mL/min/m2. A total of 12% of patients had CI>4.5 L/min/m2 pre-occlusion. There was no difference in heart rate (HR), MABP and SVI following occlusion of AVF. Mean CI reduced post-AVF occlusion (∆CI: -0.42 L/min/m2; p<0.001), as did DO2I (∆ DO2I: 45.5 mL/min/m2; p<0.001). SVRI increased (∆SVRI: 170.1 dyn/sec/cm−5/m2; p<0.001). The drop in CI which occurred post-AVF occlusion was greater in patients with Qa >2000 mL/min (-2.79 ± 0.34 vs. -0.24 ± 0.48 L/min/m2; p<0.001). There was a non-significant trend towards symptomatic heart failure in those patients with a greater ∆CI following AVF occlusion (NYHA 1: -0.1 ± 0.1 L/min/m2; NHYA 2: -0.3 ± 0.7 L/min/m2; NYHA 3: -0.7 ± 1.0 L/min/m2; p = 0.06). Conclusions The relationship between AVF blood flow, cardiac output and symptomatic cardiac disease is complex. Occlusion of an AVF leads to reduced cardiac output and improved oxygen delivery, even in asymptomatic patients. This difference is most marked in patients with high-flow AVF (>2000 mL/min). High-flow AVF with large ∆CI may lead to high cardiac output state, which is reversible on occlusion of the AVF.

The use of Tunneled Central Venous Catheters: Inevitable or System Failure?:

Purpose To evaluate reasons for tunneled central venous catheter (TCVC) usage in our prevalent hemodialysis population and assess the impact of a surgically aggressive approach to definitive access creation. Methods Clinical review of all patients in the West of Scotland dialyzing via a TCVC in November 2010 was performed. Reasons for TCVC usage and TCVC complications were evaluated. Over the subsequent year, aggressive intervention was undertaken to achieve definitive access in all suitable patients and outcomes re-evaluated a year later (November 2011). Results There was no significant difference in the proportion of patients dialyzing via a TCVC in 2010 compared to 2011 (30.3% (n=193) vs. 31.7% (n=201), respectively; p=0.56). All patients now have a “vascular access plan.” Of patients dialyzing via a TCVC in 2010, 37% had died by 2011, 22% remained on long-term line, 20% had successful arteriovenous fistula (AVF) creation, 1% had an arteriovenous graft and 2% were transplanted; 10.4% developed complications of vascular access and required ligation of a functioning AVF. A further 6.5% died within 28 days of surgery. The incidence of culture-positive Staphylococcus aureus bacteremia was 1.6 per 1,000 catheter days. Conclusions Aggressive strategies of AVF creation resulted in one-fifth of patients on a long-term TCVC having successful creation of an AVF. This was offset against high failure and significant complication rate from AVF creation in this population. One-third of patients dialyzing via a TCVC died in the subsequent year. Correct patient selection for AVF creation is essential and predialysis care must be optimized to avoid the need for TCVCs entirely.

Pain resulting from arteriovenous fistulae: prevalence and impact.

INTRODUCTION The burden of pain from cannulation of arteriovenous fistulae (AVF) and the impact it has on quality of life is poorly described in the literature. METHODOLOGY A pain score questionnaire was employed for all patients in the West of Scotland dialyzing via AVF (n = 461). Pain was assessed using visual analogue score (VAS) and McGill pain score. Patients with severe pain (VAS > 5) were compared to those with minimal pain. RESULTS The questionnaire as completed by 97.5% of the patients. Median VAS on cannulation was 3 (IQR 0.5 - 4.5). Of those who had completed the questionnaire, 24.4% had severe pain on cannulation and 3.2% experienced severe chronic pain. 53 patients (11.3%) cut a dialysis session short due to pain. Of the patients with severe chronic pain, 46.7% had a physical complication affecting their AVF (e.g., venous stenosis, pseudoaneurysm). Following treatment of the problem, pain improved in 71.4% and resolved completely in 14.3%. Brachiobasilic AVF was associated with a higher incidence of severe pain than either brachiocephalic or radiocephalic AVF (50%, 23.3% and 24.4% respectively; p = 0.03). There was a trend towards more severe pain with rope-ladder cannulation (27.7%) compared to button-hole cannulation (18.2%); however, this difference did not reach statistical significance (p = 0.09). CONCLUSIONS Pain from AVF is poorly recognized and an under-reported problem. While severe pain resulting in the avoidance of dialysis is rare, it can lead to significant difficulties and ultimate abandonment of AVF. Pain is often suggestive of an underlying anatomical problem.

A randomized controlled trial and cost-effectiveness analysis of early cannulation arteriovenous grafts versus tunneled central venous catheters in patients requiring urgent vascular access for hemodialysis

Objective: Early cannulation arteriovenous grafts (ecAVGs) are proposed as an alternative to tunneled central venous catheters (TCVCs) in patients requiring immediate vascular access for hemodialysis (HD). We compared bacteremia rates in patients treated with ecAVG and TCVC. Methods: The study randomized 121 adult patients requiring urgent vascular access for HD in a 1:1 fashion to receive an ecAVG with or without (+/−) an arteriovenous fistula (AVF; n = 60) or TCVC+/−AVF (n = 61). Patients were excluded if they had active systemic sepsis, no anatomically suitable vessels, or an anticipated life expectancy <3 months. The primary end point was the culture‐proven bacteremia rate at 6 months, with the trial powered to detect a reduction in bacteremia from 24% to 5% (&agr; = .05, &bgr; = .8). Secondary end points included thrombosis, reintervention, and mortality. A cost‐effectiveness analysis was also performed. Results: Culture‐proven bacteremia developed in 10 patients (16.4%) in the TCVC arm ≤6 months compared with two (3.3%) in the ecAVG+/−AVF arm (risk ratio, 0.2; 95% confidence interval, 0.12–0.56; P = .02). Mortality was also higher in the TCVC+/−AVF cohort (16% [n = 10] vs 5% [n = 3]; risk ratio, 0.3; 95% CI, 0.08–0.45; P = .04). The difference in treatment cost between the two arms was not significant (£11,393 vs £9692; P = .24). Conclusions: Compared with TCVC+/−AVF, a strategy of ecAVG+/−AVF reduced the rate of culture‐proven bacteremia and mortality in patients requiring urgent vascular access for HD. The strategy also proved to be cost‐neutral.

Bilateral Central Vein Stenosis: Options for Dialysis Access and Renal Replacement Therapy when all upper Extremity Access Possibilities have been Lost:

Purpose Patients with bilateral central vein stenosis present a unique challenge: treatment options are limited, largely unproven and associated with reputedly poor outcomes. Our aim was to compare patency rates of different access and renal replacement treatment (RRT) modalities in patients with bilateral central vein stenosis/occlusion. Material and methods Data on all patients presenting to a tertiary referral vascular access centre with end-stage vascular access (defined by bilateral central vein stenosis/occlusion with loss of upper limb access) over a 5-year period were included. 3, 6 and 12-month patencies of translumbar catheters (TLs), tunnelled femoral catheters (Fem), native long saphenous vein loops (SV), prosthetic mid-thigh loop grafts (ThGr), peritoneal dialysis (PD), and expedited donation after cardiac death (DCD) cadaveric renal transplants (Tx) via local allocation policies were compared using log-rank test. Kaplan–Meier survival analysis was used to estimate long-term access survival. Results One hundred forty-six vascular access modalities were attempted in 62 patients (62 Fem, 25 TL, 15 SV, 25 ThGr, 8 PD, 11 Tx). Median follow-up was 876±57 days. Three, 6 and 12-month primary-assisted patencies for each modality were as follows: Fem: 75.4%, 60% and 28%; TL: 88%, 65% and 50%; SV: 87.5%, 60% and 44.6%; ThGr: 64%, 38% and 23.5%; PD: 62.5%, 62.5% and 50%; Tx: 72.7%, 72.7% and 72.7%. SV had better secondary patency at 900 days (76.9%) than ThGr (49.2%) or Fem (35.8%) (p<0.01). No patients died as a result of loss of access. Conclusion Patients with bilateral central vein stenosis often require more than one vascular access modality to achieve a “personal access solution.” Native long saphenous vein loops provided the best long-term patency. Expedited renal transplantation with priority local allocation of DCD organs to patients with precarious vascular access provides a potential solution to this difficult problem.

Does regional compared to local anaesthesia influence outcome after arteriovenous fistula creation

BackgroundAn arteriovenous fistula is the optimal form of vascular access in patients with end-stage renal failure requiring haemodialysis. Unfortunately, approximately one-third of fistulae fail at an early stage. Different anaesthetic techniques can influence factors associated with fistula success, such as intraoperative blood flow and venous diameter. A regional anaesthetic brachial plexus block results in vasodilatation and improved short- and long-term fistula flow compared to the infiltration of local anaesthetic alone. This, however, has not yet been shown in a large trial to influence long-term fistula patency, the ultimate clinical measure of success.The aim of this study is to compare whether a regional anaesthetic block, compared to local anaesthetic infiltration, can improve long-term fistula patency.MethodsThis study is an observer-blinded, randomised controlled trial. Patients scheduled to undergo creation of either brachial or radial arteriovenous fistulae will receive a study information sheet, and consent will be obtained in keeping with the Declaration of Helsinki. Patients will be randomised to receive either: (i) an ultrasound guided brachial plexus block using lignocaine with adrenaline and levobupivicaine, or (ii) local anaesthetic infiltration with lignocaine and levobupivicaine.A total of 126 patients will be recruited. The primary outcome is fistula primary patency at three months. Secondary outcomes include primary patency at 1 and 12 months, secondary patency and fistula flow at 1, 3 and 12 months, flow on first haemodialysis, procedural pain, patient satisfaction, change in cephalic vein diameter pre- and post-anaesthetic, change in radial or brachial artery flow pre- and post-anaesthetic, alteration of the surgical plan after anaesthesia as guided by vascular mapping with ultrasound, and fistula infection requiring antibiotics.ConclusionsNo large randomised controlled trial has examined the influence of brachial plexus block compared with local anaesthetic infiltration on the long-term patency of arteriovenous fistulae. If the performance of brachial plexus block increases fistulae patency, this will have significant clinical and financial benefits as the number of patients able to commence haemodialysis when planned should increase, and the number of “redo” or revision procedures should be reduced.Trial registrationThis study has been approved by the West of Scotland Research Ethics Committee 5 (reference no. 12/WS/0199) and is registered with the ClinicalTrials.gov database (reference no. NCT01706354).

Below-target postoperative arterial blood pressure but not central venous pressure is associated with delayed graft function.

Delayed graft function (DGF) is a major issue in kidney transplantation and is associated with reduced graft and patient survival. The condition results from the summative effects of multiple injurious processes associated with transplantation with many underlying factors being nonmodifiable. Reducing cold ischemic time and machine perfusion have decreased the DGF incidence but peri-/postoperative injury resulting from suboptimal perfusion may also be critical to the development of DGF. We investigated the effect of perfusion parameters and other key variables on the incidence of DGF in 149 consecutive renal transplants. The occurrence of any recorded subtarget (70 mm Hg) mean arterial pressure (MAP) was significantly associated with DGF (perioperative P = .005; postoperative P = .002) while the occurrence of a subtarget (8 cm H(2)O) central venous pressure (CVP) among other variables was not. Routine continuous blood pressure monitoring is rare postoperatively and is shown to be more accurate than CVP in assessing renal perfusion and guiding management in the postoperative period.