The Role of Qutenza® (Topical Capsaicin 8%) in Treating Neuropathic Pain from Critical Ischemia in Patients with End-Stage Renal Disease: An Observational Cohort Study

Objective

Current treatment strategies for painful critical ischemia in patients with end-stage renal disease (ESRD) are suboptimal. A drug that is non-renally excreted has minimal systemic absorption and does not require dose adjustment in renal failure is attractive. The aim of this study was to evaluate the safety and efficacy of Qutenza® (topical capsaicin 8%) for chronic neuropathic pain from critical ischemia in patients with ESRD.

Design and Setting

A prospective cohort study was conducted in a single-center, university teaching hospital.

Patients

Twenty patients with ESRD were treated with Qutenza® for neuropathic pain from critical limb ischemia.

Methods

Patients were followed-up at 1, 6 and 12 weeks post-treatment. The primary end point was the difference in visual analog scale (VAS) between baseline and week 12. Secondary end points were Brief Pain Inventory questionnaire (BPI) scores, quality of life assessment (EQ-5D) and patient global impression of change (PGIC). Safety and tolerability data were also collected. The trial was prospectively registered with clinical trials databases (EudraCT: 2012-001586-32; NCT01704313).

Results

There was significant reduction in VAS from baseline to week 12 (-20+/-7%; P = 0.02). There was a significant reduction in all seven domains of the BPI. Quality of life also improved at 12 weeks following treatment in two of the EQ-5D domains (mobility and pain). Qutenza® was well tolerated with no significant side effects in this patient cohort, which included 20% diabetics.

Conclusions

In this small, observational study Qutenza® treatment has been shown to be effective and well-tolerated to treat neuropathic pain from critical ischemia in patients with ESRD.

A unique case of acute embolus in a renal transplant with salvage by catheter-directed thrombolysis

INTRODUCTION

Acute renal transplant emboli can be disastrous and result in loss of the renal transplant. This case was successfully treated with thrombolysis.

CASE PRESENTATION

A 66-year-old female underwent a right-sided deceased heart-beating donor renal transplant. She had excellent transplant function but presented acutely three years later with pain in the transplanted kidney, an acute rise in serum creatinine and new onset atrial fibrillation. Bedside ultrasound scan demonstrated absent transplant perfusion. Emergency angiogram confirmed acute emboli in the transplant renal artery with some kidney perfusion. Thrombolysis with alteplase and anticoagulation with heparin was commenced. Serial imaging at 24 and 36 h demonstrated significant improvement in transplant perfusion. Following a period of supportive therapy, her transplant function recovered, although not to pre-morbid baseline levels.

CONCLUSION

Consider acute embolus in a renal transplant patient with acute kidney injury, transplant tenderness and cardiac arrhythmia. Early thrombolysis may salvage renal transplants and good transplant function may be regained.

Immediate access arteriovenous grafts versus tunnelled central venous catheters: study protocol for a randomised controlled trial

BACKGROUND

Autologous arteriovenous fistulae (AVF) are the optimal form of vascular access for haemodialysis. AVFs typically require 6 to 8 weeks to "mature" from the time of surgery before they can be cannulated. Patients with end-stage renal disease needing urgent vascular access therefore traditionally require insertion of a tunnelled central venous catheter (TCVC). TCVCs are associated with high infection rates and central venous stenosis. Early cannulation synthetic arteriovenous grafts (ecAVG) provide a novel alternative to TCVCs, permitting rapid access to the bloodstream and immediate needling for haemodialysis. Published rates of infection in small series are low. The aim of this study is to compare whether TCVC ± AVF or ecAVG ± AVF provide a better strategy for managing patients requiring immediate vascular access for haemodialysis.

METHODS/DESIGN

This is a prospective randomised controlled trial comparing the strategy of TCVC ± AVF to ecAVG ± AVF. Patients requiring urgent vascular access will receive a study information sheet and written consent will be obtained. Patients will be randomised to receive either: (i) TCVC (and native AVF if this is anatomically possible) or (ii) ecAVG (± AVF). 118 patients will be recruited. The primary outcome is systemic bacteraemia at 6 months. Secondary outcomes include culture-proven bacteraemia rates at 1 year and 2 years; primary and secondary patency rates at 3, 6, 12 and 24 months; stenoses; re-intervention rates; re-admission rate; mortality and quality of life. Additionally, treatment delays, impact on service provision and cost-effectiveness will be evaluated.

DISCUSSION

This is the first randomised controlled trial comparing TCVC to ecAVG for patients requiring urgent vascular access for haemodialysis. The complications of TCVC are considered an unfortunate necessity in patients requiring urgent haemodialysis who do not have autologous vascular access. If this study demonstrates that ecAVGs provide a safe and practical alternative to TCVC, this could instigate a paradigm shift in nephrology thinking and access planning.

TRIAL REGISTRATION

This study has been approved by the West of Scotland Research Ethics Committee 4 (reference no. 13/WS/0087, 28 August 2013) and is registered with the International Standard Randomised Controlled Trial Number Register (reference no. ISRCTN80588541 , 27 May 2014).

Delayed graft function is a syndrome rather than a diagnosis

OBJECTIVES

Delayed graft function is a significant prognostic indicator after renal transplantation. We hypothesized that delayed graft function is not a single entity, and different patterns of delayed graft function reflect various underlying pathological processes.

MATERIALS AND METHODS

An analysis of 762 renal transplants was performed, showing serum creatinine was charted serially for the first 30 days after transplant. Measurements were obtained: time on hemodialysis; time to peak creatinine; time for creatinine to half; time for creatinine to within 10% of baseline.

RESULTS

Four patterns of delayed graft function were identified. There was no association between pattern of delayed graft function, and 1-year graft survival or serum creatinine at 1 year. Time for creatinine to > 15 days was associated with a higher creatinine level at 1 year than it was with patients with time for creatinine to half < 5 days (300.6 ± 54.3 vs 211.3 ± 26.0 μmol/L; P < .01). Patients with 1-year creatinine concentrations > 180 μmol/L had longer time on hemodialysis and time for creatinine to half than did those with 1-year creatinine concentrations ≤ 180 μmol/L (9.2 ± 1.3 μmol/L vs 7.0 ± 0.7 μmol/L; P = .03; and 11.6 ± 1.7 μmol/L vs 6.0 ± 0.4 μmol/L; P < .001). Time for creatinine to half of 6.5 days (sensitivity 67.3%; specificity 79.4%; area under the curve, 0.70) was the best predictor of a 1-year creatinine concentration ≤ 180 μmol/L.

CONCLUSIONS

Delayed graft function is not a single entity; rather; it is the most common presentation of a heterogeneous variety of pathologies. Its rate of resolution of renal function is the best predictor of long-term graft outcome.

Renal function, uraemia and early arteriovenous fistula failure

BACKGROUND

Guidance varies regarding the optimal timing of arteriovenous fistula (AVF) creation. The aim of this study was to evaluate the association between uraemia, haemodialysis and early AVF failure.

METHODS

Immunoblotting and cell proliferation assays were performed on vascular smooth muscle cells (VSM) cells isolated from long saphenous vein samples to evaluate the cells' ability to proliferate when stimulated with uraemic (post-dialysis) and hyperuraemic (pre-dialysis) serum. Clinical data was collected prospectively for 569 consecutive radiocephalic (RCF) and brachiocephalic (BCF) fistulae. The primary outcome was AVF failure at 6 weeks. Dialysis status (haemodialysis (HD); pre-dialysis (Pre-D)), eGFR and serum urea were evaluated to determine if they affected early AVF failure.

RESULTS

Human VSM cells demonstrated increased capacity to proliferate when stimulated with hyperuraemic serum. There was no significant difference in early failure rate of either RCF or BCF depending on dialysis status (pre-D RCF 31.4% (n=188); pre-D BCF 22.4% (n=165); HD RCF 29.3% (n=99); HD BCF 25.9% (n=116); p=0.34). There was no difference in mean eGFR between those patients with early AVF failure and those without (11.2+/-0.2 ml/min/1.73 m2 vs. 11.6+/-0.4 ml/min/1.73 m2; p=0.47). Uraemia was associated with early AVF failure (serum urea: 35.0+/-0.7 mg/dl vs. 26.6+/-0.3 mg/dl (p<0.001)).

CONCLUSIONS

We present the first in vivo evidence of an association between adverse early AVF outcomes and uraemia. This is supported mechanistically by in vitro work demonstrating a pro-mitogenic effect of hyperuraemic serum. We hypothesise that uraemia-driven upregulation of VSM cell proliferation at the site of surgical insult in contributes to higher early AVF failure rates.

Abstract 554: Rabbit Arteriovenous Fistula Model and Identification of a Therapeutic Agent to Increase Fistula Patency

An arteriovenous fistula (AVF) is a vein graft which is created to permit vascular access allowing haemodialysis to be performed in renal failure patients. AVF using native tissues is the preferred surgical option; however AVF are associated with failure rates as high as 50% at 6 months. Failure is principally due to vascular cell proliferation, leading to the development of neointima causing stenosis and impaired blood flow. The aims of this study were to 1) develop a rabbit model of AVF remodelling, 2) investigate the contribution of cannulation injury in AVF remodelling and 3) identify a potential therapeutic which could be delivered topically to reduce AVF stenosis.

The proposed model was an AVF created between the femoral artery and vein of a New Zealand white rabbit. Briefly, the fistula was fashioned by creating a side to side anastomosis, followed by occlusion of the distal vein. Over phase I of the study (days 1-28) maturation of the vein was evident by the presence of a pulsatile flow in the venous branch of the AVF, as well as a significant increase in venous blood velocity from 55.2± 6.0cm/s at day 10 to 68.4± 3.1cm/s by day 28 (p<0.05). A degree of medial/adventitial thickening was also evident at this time point. Rabbits were assigned to 3 groups for phase II of the study (days 29-56). The control group received no intervention, the injury group received cannulation to the AVF every 48-72 hrs, and the injury plus diclofenac group received the same frequency of injury and topical diclofenac (1.16% of diclofenac diethylammonium) twice a day, 5 days a week. In the control group, vein wall width increased significantly from 10.5± 0.9μM in the counter lateral vein to 16.6± 1.6μM in the AVF (p<0.05). Cannulation injury caused vein wall thickness to significantly increase to 46.8± 5.7μM (p<0.05). With diclofenac treatment, vein wall width decreased significantly to 15.8± 1.8μM (p<0.05).

These results show for the first time that cannulation injury significantly contributes to AVF remodelling in vivo . Topical treatment with diclofenac, which has anti-inflammatory as well as anti-proliferative properties, appears to reduce injury driven remodelling within AVF. Therefore, topical diclofenac could be used as a prophylactic treatment to reduce vascular stenosis in AVF.

Acute kidney injury: outcomes and quality of care

BACKGROUND

Deficiencies in management have been highlighted as contributory factors in the death of many patients with acute kidney injury (AKI). However, there is little evidence addressing the quality of care provided to patients with milder AKI.

AIM

The aim of this study is to evaluate the quality of care provided to a non-select cohort of patients with AKI and evaluate discrepancies in causation, recognition and management.

DESIGN

Retrospective inception cohort study.

METHODS

Demographic data were collected for all 1577 patients admitted to a University Teaching Hospital during a 1-month period. Baseline, admission and peak creatinine were correlated with mortality and length of hospital admission. AKI was classified according to Kidney Disease Improving Global Outcomes criteria. A retrospective case note review of all patients with AKI was carried out to evaluate quality of documentation and clinical management of AKI. Multivariate analysis was undertaken to determine risk factors for AKI.

RESULTS

Incidence of AKI on admission was 4.6%. A further 10.3% developed AKI while in hospital. All cause mortality was 4-fold higher among patients with AKI compared with those without (19 vs. 3.8%; P < 0.001). Mortality was significantly higher in those patients who developed AKI while an in-patient compared with those with AKI on admission (27.3 vs. 11.8%; P < 0.001). Diabetes, clinician perception of frailty, age and treatment with angiotensin-converting enzyme inhibitor prior to admission were found to be independent risk factors for AKI. AKI was unrecognized in 23.5% of patients, two-thirds of whom were discharged without resolution of renal function. Significant weaknesses in management were poorly kept fluid balance charts (48.2%), failure to withhold nephrotoxic drugs (38.8%) and failure to act upon abnormal biochemistry (41%) in a timely fashion.

CONCLUSION

AKI is common in hospitalized patients and associated with a significant increase in hospital stay and mortality. AKI is often found in conjunction with other organ failure and in many cases is not preventable. Nevertheless clinicians need to be more vigilant of small creatinine rises to permit early intervention particularly among elderly and frail patients.

The prognostic significance of iliac vessel calcification in renal transplantation

BACKGROUND

Peripheral vascular disease and major extremity amputation are common in patients with established renal failure and are associated with considerable morbidity. Several studies have shown high rates of amputation following simultaneous pancreas-kidney transplantation, but there is minimal literature on the incidence of amputation following renal transplantation. Furthermore, there is little evidence regarding the best method of predicting which patients might be at risk of developing peripheral vascular complications after transplantation.

METHODS

We undertook a 5 year follow-up on the cohort of patients who were on our renal transplant waiting list 5 years ago (January 2007). At this time, it was standard practice within our unit for all patients to have routine pelvic x-rays to assess for vascular calcification of the iliac vessels at the time of activation onto the transplant waiting list. Any patients with moderate/severe calcification on x-ray, which may complicate transplantation, were referred for computed tomography angiogram (CTA) of their aorto-iliac vessels. Mortality, transplantation outcomes, and amputation rates at 5 years were correlated with the severity of calcification on preoperative imaging.

RESULTS

One hundred eighty-seven patients were on the waiting list for renal transplantation in January 2007 (92 men; mean age, 58.3 +/- 6.2 years). Ninety-three patients received a transplant during the subsequent 5 years. By January 2012, 82 patients had a functioning transplant, 45 remained on the waiting list (5 suspended), 40 patients had died, and 20 were alive but no longer on the waiting list. Seventy-three (39.5%) had moderate or severe calcification on plain x-ray and went on to have CTA. Of these patients, 16 (21.9%) had extensive calcification affecting all the iliac vessels and were removed from the waiting list as a result. Preoperative imaging was useful in determining the side for surgery in a further 18 patients (24.3%). Twenty-two patients developed vascular complications. Nineteen (86.4%) had moderate-severe vascular calcification on imaging. Four of the patients with vascular complications (18.2%) underwent transplantation (2 had below knee amputation (BKA) prior to transplantation; 1 developed distal ischemia on the same side as the transplantation 2 years postoperatively; 1 had bilateral above knee amputation (AKA) approximately 2 years after transplantation). Eleven (50%) of the patients with vascular complications were dead at 5 years of follow-up. Mortality and amputation rates were higher in patients with moderate-severe calcification than minimal calcification (30.1% vs 16.6%; P = .02 and 10.9% vs 1.8%; P = .003, respectively). There was no difference in rates of delayed graft function (DGF), biopsy-proven acute rejection (BPAR), or creatinine at 1 year between patients who underwent transplantation with moderate-severe calcification and those without, however, intraoperative vascular complications (26.7% vs 3%; P < .001), graft loss (28.1% vs 3.4%; P = .01), and death with a functioning transplant (9.7% vs 1.6%; P = .04) rates were higher in patients with extensive calcification compared with those without.

CONCLUSIONS

Plain x-ray of the pelvis is a useful screening tool to identify those patients who may require further detailed vascular imaging prior to transplantation. Amputation rates following renal transplantation are low and peripheral vascular disease (PVD) in isolation should not preclude transplantation. Nevertheless, significant vascular calcification is predictive of mortality both with and without transplantation and graft loss in patients with a renal transplant.

Five-year outcomes after a change from a cyclosporin-based to a 'low-dose' tacrolimus-based primary immunosuppression regimen for incident kidney transplants--the Glasgow experience

In January 2007, our centre changed from a cyclosporin (CyA)/azathioprine (Aza)/ prednisolone (Pred) primary immunosuppression regimen (with basiliximab induction and mycophenolate mofetil [MMF] for those at immunologically high risk) to a tacrolimus (Tac) (low dose)/MMF/Pred regimen with basiliximab induction, following presentation of Symphony trial results. This analysis assesses the impact of this change on 5-year outcomes. Three hundred consecutive renal-only transplants were identified: 140 from the 2005-06 era and 160 from the 2007-08 era. The proportions of living donor (37.5 vs. 22.9%; p = 0.04) and donors after circulatory death (11.9 vs. 5.0%; p = 0.03) were higher in the 2007-08 cohort. Five-year actuarial patient survival was higher in the 2007-08 cohort (96.8 vs. 87.1%; p = 0.003), with a trend toward higher 5-year transplant survival (84.7 vs. 76.3%; p = 0.08). Estimated glomerular filtration rate (eGFR) was higher than in the 2005-06 era at 1 (53.5 vs. 44.5 ml/min/1.73m2; p = 0.0006) and 3 years (50.9 vs. 43.4 ml/min/1.73m2; p = 0.02), with a trend toward higher eGFR at 5 years (41.8 vs. 49.6 ml/min/1.73m2; p = 0.09). Differences were consistent when living donor and deceased donor transplants were analysed separately. In a "real world" population, a change from a CyA-based to a Tac (low-dose)/MMF/Pred primary immunosuppression regimen has been associated with better 5-year outcomes.

Cellular senescence in pretransplant renal biopsies predicts postoperative organ function

Older and marginal donors have been used to meet the shortfall in available organs for renal transplantation. Post-transplant renal function and outcome from these donors are often poorer than chronologically younger donors. Some organs, however, function adequately for many years. We have hypothesized that such organs are biologically younger than poorer performing counterparts. We have tested this hypothesis in a cohort of preimplantation human renal allograft biopsies ( n = 75) that have been assayed by real-time polymerase chain reaction for the expression of known markers of cellular damage and biological aging, including CDKN2A, CDKN1A, SIRT2 and POT1. These have been investigated for any associations with traditional factors affecting transplant outcome (donor age, cold ischaemic time) and organ function posttransplant (serum creatinine levels). Linear regression analyses indicated a strong association for serum creatinine with pre-transplant CDKN2A levels ( p = 0.001) and donor age ( p = 0.004) at 6 months post-transplant. Both these markers correlated significantly with urinary protein to creatinine ratios ( p = 0.002 and p = 0.005 respectively), an informative marker for subsequent graft dysfunction. POT1 expression also showed a significant association with this parameter ( p = 0.05). Multiple linear regression analyses for CDKN2A and donor age accounted for 24.6% ( p = 0.001) of observed variability in serum creatinine levels at 6 months and 23.7% ( p = 0.001) at 1 year posttransplant. Thus, these data indicate that allograft biological age is an important novel prognostic determinant for renal transplant outcome.