Brendon L. Neuen

Predictors of Patency after Balloon Angioplasty in Hemodialysis Fistulas: A Systematic Review

Percutaneous transluminal angioplasty (PTA) is an established treatment for dysfunctional hemodialysis fistulas. This article systematically reviews evidence for predictors of patency after PTA. Outcomes assessed were primary, assisted primary, and secondary patency after intervention, and findings were summarized descriptively. This review included 11 nonrandomized observational studies of 965 fistulas in 939 patients. Follow-up ranged from 0 days to 10 years. Study quality was overall suboptimal. Newer fistulas and longer lesion length may be associated with primary patency loss after PTA. Further studies are needed to confirm these findings, to identify potentially modifiable factors, and to guide the testing of new endovascular devices.

Factors Associated with Patency Following Angioplasty of Hemodialysis Fistulae

PURPOSE Patency after percutaneous transluminal angioplasty of native hemodialysis arteriovenous fistulae (AVFs) is highly variable. This study aimed to identify predictors of patency following angioplasty in native AVFs. MATERIALS AND METHODS All endovascular procedures performed in native AVFs between 2005 and 2013 at two institutions were retrospectively reviewed. Clinical, anatomic, biochemical, and medication variables were subjected to univariate and multivariate Cox regression analysis to identify predictors of postintervention primary and secondary patency. RESULTS During the study period, 207 patients underwent first angioplasty of their AVF. Follow-up ranged from 14 days to 8 years, during which another 247 endovascular interventions were performed to maintain patency. Postintervention primary patency rates at 6, 12, and 24 months were 66%, 49%, and 29%, respectively. Postintervention secondary patency rates at 6, 12, and 24 months were 94%, 84%, and 79%, respectively. On multivariate adjusted Cox regression analysis, upper-arm AVFs (P = .00072), AVFs less than 6 months of age (P = .0014), presence of multiple stenoses (P = .019), and degree of initial stenosis (P = .016) were significantly associated with shorter postintervention primary patency. A previously failed AVF was the only significant predictor of postintervention secondary patency loss (P = .0053). CONCLUSIONS Anatomic factors related to the AVF location, AVF age, and the extent of the lesion are important predictors of restenosis after balloon angioplasty. Traditional cardiovascular risk factors, metabolic and inflammatory markers, and medications were not associated with postintervention patency.

Neutrophil-lymphocyte ratio predicts cardiovascular and all-cause mortality in hemodialysis patients.

Abstract Neutrophil–lymphocyte ratio (NLR) is a marker of systemic inflammation that has been shown to predict mortality in patients with malignancies, ischemic heart disease and peripheral vascular disease. Its prognostic value in hemodialysis patients is unclear. The aims of this study were to: (i) explore the relationship between NLR and other biochemical parameters and (ii) to examine the value of NLR as a predictor of cardiovascular and all-cause mortality in hemodialysis patients. The study included all the incident hemodialysis patients from a single center between 2007 and 2012. NLR was calculated using samples obtained 3 months after commencing hemodialysis. One hundred seventy hemodialysis patients were included with a median follow-up of 37 months. There were 54 deaths (32%). NLR was positively correlated with C-reactive protein (r = 0.24, p = 0.0023) and negatively correlated with hemoglobin (r = −0.27, p = 0.00048), albumin (r = −0.23, p = 0.0034) and total cholesterol (r = −0.17, p = 0.049) levels. In multivariate Cox regression, NLR was independently associated with both all-cause mortality (adjusted hazard ratio [HR] 1.4; 95% confidence interval [CI], 1.2–1.6; p ≤ 0.0001) and cardiovascular death (HR 1.3, 95% CI 1.1–1.6, p = 0.0032). Other predictors of all-cause mortality were age (HR 1.6 per decade; 95% CI, 1.2–2.1; p = 0.0017), body mass index (HR 0.93; 95% CI, 0.88–0.98; p = 0.0047), albumin (HR 0.91; 95% CI, 0.86–0.97; p = 0.0035) and peripheral vascular disease (HR 2.7; 95% CI, 1.4–5.1; p = 0.0023). NLR is a practical, cost-efficient and easy to use predictor of cardiovascular and all-cause mortality in incident hemodialysis patients.

Global kidney disease

www.thelancet.com Vol 382 October 12, 2013 1243 Submissions should be made via our electronic submission system at http://ees.elsevier.com/ thelancet/ for the management of patients with chronic kidney disease, including renal replacement therapies. However, the Social Security System (Essalud)— which covers 20% of the population— has a chronic kidney disease programme. Through MINSA, the care of patients requiring renal transplantation is limited to general hospitals and haemodialysis is provided by hospitals with self-initiated dialysis centres with limited capacity, mostly in the capital, Lima. There are several remote regions that do not have dialysis centres or nephrologists. The financing of dialysis therapy is covered by the Comprehensive Health System (SIS) for patients in extreme poverty, up to a maximum of €10 700 per patient. In practice, the funding is limited by the shortage of dialysis centres or places in MINSA hospitals, and some patients cannot receive dialysis therapy. The main problem for planning a comprehensive programme for patients with chronic kidney disease in Peru is the absence of studies evaluating the number of patients with chronic kidney disease, including those requiring renal replacement therapies. Likewise, there are no official data on mortality, nor on abandonment of therapy, in these patients. Given the scarcity of centres and nephrologists, we anticipate that abandonment of therapy might be important. Health coverage in Peru is still insuffi cient, and is not in line with the economic growth of the country.

Clinical presentation, treatment and outcome of focal segmental glomerulosclerosis in Far North Queensland Australian adults

The aim is to describe the clinical features, treatment and outcomes in Australian adults with focal segmental glomerulosclerosis and identify predictors of disease progression and all‐cause mortality.

Endovascular stent placement for hemodialysis arteriovenous access stenosis

This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss.

Indications for fistulography and correlation with detection of arteriovenous fistula stenosis

Aims: To identify the indications for fistulograms and determine correlation between indication and radiological findings. Background: Dialysis access stenosis is the most common cause of access dysfunction. Clinical monitoring or vascular access surveillance abnormalities prompt a fistulogram. At our institution, fistulogram is primarily used to confirm stenosis. Methods: A retrospective observational study was conducted on 245 fistulograms performed at our institution over a two year period from January 2012 to December 2013. The indication for referral, fistulogram findings, type of fistula and demographic data were obtained. Results: Total of 75.5% (185 of 245) fistulograms performed confirmed stenosis. The most frequent clinical indication was high venous pressures – 18.4% (45 of 245) and the most common surveillance indication was abnormal access flow (Transonic®) – 17.1% (42 of 245). The average age was 57 years, with 35.9% Aboriginal and 28.2% Torres Straight Islander ethnicity. The most common type of vascular access was radiocephalic fistula (49.8%) followed by brachiocephalic fistula (43.3%). Further analysis of variables, using bivariate logistic regression analysis, failed to reveal any significant correlation between indications for referral and finding of stenosis. However, increased venous pressure tends to be associated with stenosis (Odds ratio 2.0, 95% CI = 0.84–4.7, P = 0.12). Both venous hypertension (Odds ratio 0.10, 95% CI = 0.011–1.0, P = 0.052) and development of collaterals (Odds ratio 0.077, 95% CI = 0.0084–0.70, P = 0.023) were associated with negative fistulograms. Conclusions: At our institution, the majority of fistulograms demonstrated access stenosis, based on established referral indications. Both venous hypertension and development of collaterals as referral indications were associated with less likelihood of finding vascular access stenosis in this cohort.Aim: To examine the value of neutrophil-lymphocyte ratio (NLR) as a marker of inflammation and predictor of all-cause mortality in patients with end-stage kidney disease (ESKD). Background: NLR is a marker of systemic inflammation that has been shown to predict mortality in patients with coronary and peripheral vascular disease. In contrast to albumin, NLR is unlikely to be affected by nutritional status. Its prognostic value in ESKD patients is unclear. Methods: We retrospectively reviewed all consecutive haemodialysis patients between January 2007 and December 2011 at a single centre. We recorded patients full blood count and other biochemistry three months after commencement of dialysis. Correlations between NLR and other metabolic and inflammatory markers were evaluated using Pearsons r coefficient. The prognostic value of NLR was tested using Kaplan Meier, univariate and multivariate Cox analyses adjusted for Australian and New Zealand Dialysis and Transplant Registry data. Results: 140 haemodialysis patients were included with median follow-up of 36 months and overall mortality of 41% (58 patients). Neutrophil-lymphocyte ratio was positively correlated with C-reactive protein (r = 0.48, P < 0.01) and negatively correlated with haemoglobin (r = -0.32, P < 0.01) and albumin (r = -0.40, P < 0.01). In Kaplan Meier analysis, NLR (stratified into tertiles) was associated with all-cause mortality (log-rank, P = 0.01). In multivariate Cox analysis, NLR was independently associated with all-cause mortality (HR 1.09, 95% CI 1.01– 1.17 P = 0.03). Other predictors of all-cause mortality in multivariate analysis were low albumin (HR 0.89, 95% CI 0.89–0.94 P < 0.01) and history of cardiovascular disease (HR 2.29, 95% CI 1.25–4.48 P = 0.01). Conclusions: Neutrophil-lymphocyte ratio correlates with other markers of systemic inflammation in ESKD patients and is associated with poor survival. The extent to which other confounding factors affect these results is unknown.Aim: To determine whether: (1) systemic expression of endogenous secretory RAGE (esRAGE) after the induction of diabetes can prevent the development of diabetic nephropathy (DN) in mice with streptozotocin-induced diabetes; (2) the protective effects of esRAGE are attributable to interruption of signaling via the HMGB1receptors (TLR2, TLR4 and RAGE). Background: We have reported that systemic overexpression of esRAGE attenuates diabetic kidney injury. esRAGE is a soluble decoy receptor that can competitively bind ligands for TLRs/RAGE, including HMGB1. Here we test the hypothesis that the protective effects of esRAGE are attributable to interruption of signaling via the HMGB1 receptors (TLR2, TLR4 and RAGE). Methods: DN was induced in WT, TLR4−/− and TLR2−/− mice by intraperitoneal injection of streptozotocin. At 2 weeks after streptozotocin injection, mice received an IP injection of 5 × 1011 vector genome copies (VGC) rAAV encoding either esRAGE or HSA, or saline-control. Samples were collected at week 12 post-induction of diabetes. Results: Diabetic mice that received rAAV-esRAGE, rAAV-HSA or saline developed equivalent degrees of hyperglycaemia. Diabetic WT-mice given rAAVHSA or saline developed significant albuminuria versus non-diabetic WT-mice (ACR309 ± 213 & 313 ± 215 versus 55 ± 10, P < 0.05–0.01), whilst rAAVesRAGE treated-diabetic-mice were protected (118 ± 42, P < 0.05). WT diabetic-mice developed histological damage including glomerular hypertrophy, podocyte injury, macrophage accumulation and interstitial fibrosis. These changes were significantly attenuated in diabetic mice given rAAV-esRAGE versus rAAV-HSA (P < 0.05–0.01).While both TLR2−/− mice and TLR4−/−mice were partially protected against diabetic nephropathy, esRAGE treatment provided additional protection to TLR2−/− mice, but not TLR4−/− mice. A further study of esRAGE treatment in RAGE−/− mice is underway. Conclusions: High-level expression of serum esRAGE after the induction of diabetes provided partial protection against the development of DN in mice with streptozotocin-induced diabetes, which may operate through the TLR4 pathway.

Neutrophil-lymphocyte ratio as a marker of inflammation and predictor of mortality in patients with end-stage kidney disease

Aims: To identify the indications for fistulograms and determine correlation between indication and radiological findings. Background: Dialysis access stenosis is the most common cause of access dysfunction. Clinical monitoring or vascular access surveillance abnormalities prompt a fistulogram. At our institution, fistulogram is primarily used to confirm stenosis. Methods: A retrospective observational study was conducted on 245 fistulograms performed at our institution over a two year period from January 2012 to December 2013. The indication for referral, fistulogram findings, type of fistula and demographic data were obtained. Results: Total of 75.5% (185 of 245) fistulograms performed confirmed stenosis. The most frequent clinical indication was high venous pressures – 18.4% (45 of 245) and the most common surveillance indication was abnormal access flow (Transonic®) – 17.1% (42 of 245). The average age was 57 years, with 35.9% Aboriginal and 28.2% Torres Straight Islander ethnicity. The most common type of vascular access was radiocephalic fistula (49.8%) followed by brachiocephalic fistula (43.3%). Further analysis of variables, using bivariate logistic regression analysis, failed to reveal any significant correlation between indications for referral and finding of stenosis. However, increased venous pressure tends to be associated with stenosis (Odds ratio 2.0, 95% CI = 0.84–4.7, P = 0.12). Both venous hypertension (Odds ratio 0.10, 95% CI = 0.011–1.0, P = 0.052) and development of collaterals (Odds ratio 0.077, 95% CI = 0.0084–0.70, P = 0.023) were associated with negative fistulograms. Conclusions: At our institution, the majority of fistulograms demonstrated access stenosis, based on established referral indications. Both venous hypertension and development of collaterals as referral indications were associated with less likelihood of finding vascular access stenosis in this cohort.Aim: To examine the value of neutrophil-lymphocyte ratio (NLR) as a marker of inflammation and predictor of all-cause mortality in patients with end-stage kidney disease (ESKD). Background: NLR is a marker of systemic inflammation that has been shown to predict mortality in patients with coronary and peripheral vascular disease. In contrast to albumin, NLR is unlikely to be affected by nutritional status. Its prognostic value in ESKD patients is unclear. Methods: We retrospectively reviewed all consecutive haemodialysis patients between January 2007 and December 2011 at a single centre. We recorded patients full blood count and other biochemistry three months after commencement of dialysis. Correlations between NLR and other metabolic and inflammatory markers were evaluated using Pearsons r coefficient. The prognostic value of NLR was tested using Kaplan Meier, univariate and multivariate Cox analyses adjusted for Australian and New Zealand Dialysis and Transplant Registry data. Results: 140 haemodialysis patients were included with median follow-up of 36 months and overall mortality of 41% (58 patients). Neutrophil-lymphocyte ratio was positively correlated with C-reactive protein (r = 0.48, P < 0.01) and negatively correlated with haemoglobin (r = -0.32, P < 0.01) and albumin (r = -0.40, P < 0.01). In Kaplan Meier analysis, NLR (stratified into tertiles) was associated with all-cause mortality (log-rank, P = 0.01). In multivariate Cox analysis, NLR was independently associated with all-cause mortality (HR 1.09, 95% CI 1.01– 1.17 P = 0.03). Other predictors of all-cause mortality in multivariate analysis were low albumin (HR 0.89, 95% CI 0.89–0.94 P < 0.01) and history of cardiovascular disease (HR 2.29, 95% CI 1.25–4.48 P = 0.01). Conclusions: Neutrophil-lymphocyte ratio correlates with other markers of systemic inflammation in ESKD patients and is associated with poor survival. The extent to which other confounding factors affect these results is unknown.Aim: To determine whether: (1) systemic expression of endogenous secretory RAGE (esRAGE) after the induction of diabetes can prevent the development of diabetic nephropathy (DN) in mice with streptozotocin-induced diabetes; (2) the protective effects of esRAGE are attributable to interruption of signaling via the HMGB1receptors (TLR2, TLR4 and RAGE). Background: We have reported that systemic overexpression of esRAGE attenuates diabetic kidney injury. esRAGE is a soluble decoy receptor that can competitively bind ligands for TLRs/RAGE, including HMGB1. Here we test the hypothesis that the protective effects of esRAGE are attributable to interruption of signaling via the HMGB1 receptors (TLR2, TLR4 and RAGE). Methods: DN was induced in WT, TLR4−/− and TLR2−/− mice by intraperitoneal injection of streptozotocin. At 2 weeks after streptozotocin injection, mice received an IP injection of 5 × 1011 vector genome copies (VGC) rAAV encoding either esRAGE or HSA, or saline-control. Samples were collected at week 12 post-induction of diabetes. Results: Diabetic mice that received rAAV-esRAGE, rAAV-HSA or saline developed equivalent degrees of hyperglycaemia. Diabetic WT-mice given rAAVHSA or saline developed significant albuminuria versus non-diabetic WT-mice (ACR309 ± 213 & 313 ± 215 versus 55 ± 10, P < 0.05–0.01), whilst rAAVesRAGE treated-diabetic-mice were protected (118 ± 42, P < 0.05). WT diabetic-mice developed histological damage including glomerular hypertrophy, podocyte injury, macrophage accumulation and interstitial fibrosis. These changes were significantly attenuated in diabetic mice given rAAV-esRAGE versus rAAV-HSA (P < 0.05–0.01).While both TLR2−/− mice and TLR4−/−mice were partially protected against diabetic nephropathy, esRAGE treatment provided additional protection to TLR2−/− mice, but not TLR4−/− mice. A further study of esRAGE treatment in RAGE−/− mice is underway. Conclusions: High-level expression of serum esRAGE after the induction of diabetes provided partial protection against the development of DN in mice with streptozotocin-induced diabetes, which may operate through the TLR4 pathway.

Upper arm fistulae and multiple stenoses influence haemodialysis arteriovenous fistulae patency after balloon angioplasty

Aim: Patency after percutaneous balloon angioplasty (PTA) for haemodialysis fistula stenosis is highly variable. This study aimed to assess factors associated with patency following first episode of treatment with PTA. Background: Restenosis recurs commonly after PTA. Previous studies have shown that some intrinsic fistula and biochemical factors may influence patency after PTA. Methods: We retrospectively reviewed all endovascular procedures performed by nephrologists between 2007 and 2012 at a single centre. Anatomical, clinical, biochemical and medication information was subjected to cox regression analysis to identify factors influencing post-intervention patency. Results: 120 patients were identified as having first episode treatment with PTA. During a median follow-up period of 22.66 months (5.24–53 months), 171 follow-up procedures were performed. Post-intervention primary patency rates at 6, 12 and 18 months were 46%, 25% and 15% respectively. Cumulative (functional) patency rates at 6, 12 and 18 months were 97%, 94 and 92% respectively with 1.4 additional procedures per patient. In univariate cox regression analysis, the presence of multiple lesions (p = 0.037) was associated with early restenosis at 6 months, while upper arm fistulae were associated with early restenosis (p = 0.004) and shorter primary patency (p = 0.001). Other anatomical characteristics (fistula age, lesion length, pre-procedure stenosis), clinical history (diabetes, coronary and peripheral artery disease), medications, and biochemical parameters (HbA1c, CRP, albumin and lipids) did not influence patency. Conclusion: Multiple stenoses and upper arm fistulae may be associated with shorter patency after PTA. More large volume prospective studies are required to further assess factors associated with patency after PTA in haemodialysis fistulae, particularly the role of metabolic and inflammatory markers.

Factors influencing haemodialysis arteriovenous fistula patency after balloon angioplasty: a systematic review

Aim: Patency after percutaneous balloon angioplasty (PTA) for haemodialysis fistula stenosis is highly variable. This study aimed to assess factors associated with patency following first episode of treatment with PTA. Background: Restenosis recurs commonly after PTA. Previous studies have shown that some intrinsic fistula and biochemical factors may influence patency after PTA. Methods: We retrospectively reviewed all endovascular procedures performed by nephrologists between 2007 and 2012 at a single centre. Anatomical, clinical, biochemical and medication information was subjected to cox regression analysis to identify factors influencing post-intervention patency. Results: 120 patients were identified as having first episode treatment with PTA. During a median follow-up period of 22.66 months (5.24–53 months), 171 follow-up procedures were performed. Post-intervention primary patency rates at 6, 12 and 18 months were 46%, 25% and 15% respectively. Cumulative (functional) patency rates at 6, 12 and 18 months were 97%, 94 and 92% respectively with 1.4 additional procedures per patient. In univariate cox regression analysis, the presence of multiple lesions (p = 0.037) was associated with early restenosis at 6 months, while upper arm fistulae were associated with early restenosis (p = 0.004) and shorter primary patency (p = 0.001). Other anatomical characteristics (fistula age, lesion length, pre-procedure stenosis), clinical history (diabetes, coronary and peripheral artery disease), medications, and biochemical parameters (HbA1c, CRP, albumin and lipids) did not influence patency. Conclusion: Multiple stenoses and upper arm fistulae may be associated with shorter patency after PTA. More large volume prospective studies are required to further assess factors associated with patency after PTA in haemodialysis fistulae, particularly the role of metabolic and inflammatory markers.