Safety and efficacy of arteriovenous fistula angioplasties performed by nephrologists: report from a Brazilian interventional nephrology center / Segurança e eficácia de angioplastias de fístulas arteriovenosas realizadas por nefrologistas: relato de um centro de nefrologia intervencionista brasileiro

ABSTRACT Introduction: Arteriovenous fistulas (AVF) are the first choice vascular access for hemodialysis. However, they present a high incidence of venous stenosis leading to thrombosis. Although training in interventional nephrology may improve accessibility for treatment of venous stenosis, there is limited data on the safety and efficacy of this approach performed by trained nephrologists in low-income and developing countries. Methods: This study presents the retrospective results of AVF angioplasties performed by trained nephrologists in a Brazilian outpatient interventional nephrology center. The primary outcome was technical success rate (completion of the procedure with angioplasty of all stenoses) and secondary outcomes were complication rates and overall AVF patency. Findings: Two hundred fifty-six angioplasties were performed in 160 AVF. The technical success rate was 88.77% and the main cause of technical failure was venous occlusion (10%). The incidence of complications was 13.67%, with only one patient needing hospitalization and four accesses lost due to the presence of hematomas and/or thrombosis. Grade 1 hematomas were the most frequent complication (8.2%). The overall patency found was 88.2 and 80.9% at 180 and 360 days after the procedure, respectively. Conclusion: Our findings suggest that AVF angioplasty performed by trained nephrologists has acceptable success rates and patency, with a low incidence of major complications as well as a low need for hospitalization.

RESUMO Introdução: As fístulas arteriovenosas (FAV) são a primeira escolha de acesso vascular para hemodiálise. No entanto, elas apresentam uma alta incidência de estenoses venosas levando à trombose. Embora o treinamento em nefrologia intervencionista possa melhorar a acessibilidade para o tratamento das estenoses venosas, há dados limitados sobre a segurança e a eficácia desta abordagem realizada por nefrologistas treinados em países em desenvolvimento e de baixa renda. Métodos: Este estudo apresenta os resultados retrospectivos de angioplastias de FAV realizadas por nefrologistas treinados em um centro ambulatorial brasileiro de nefrologia intervencionista. O desfecho primário foi a taxa de sucesso técnico (conclusão do procedimento com angioplastia de todas as estenoses) e os desfechos secundários foram taxas de complicação e a patência geral das FAV. Achados: Duzentas e cinquenta e seis angioplastias foram realizadas em 160 FAV. A taxa de sucesso técnico foi de 88,77% e a principal causa de falha técnica foi a oclusão venosa (10%). A incidência de complicações foi de 13,67%, com apenas um paciente necessitando de internação e quatro acessos perdidos devido à presença de hematomas e/ou trombose. Hematomas de grau 1 foram a complicação mais frequente (8,2%). A patência geral encontrada foi de 88,2 e 80,9% a 180 e 360 dias após o procedimento, respectivamente. Conclusão: Nossos achados sugerem que a angioplastia de FAV realizada por nefrologistas treinados tem taxas de sucesso e patência aceitáveis, com uma baixa incidência de complicações maiores, bem como uma baixa necessidade de hospitalização.

Real-world data from selective laser trabeculoplasty in Brazil.

Evaluate real-world data of outcomes from selective laser trabeculoplasty (SLT) performed in different regions of Brazil and investigate potential predictors of success associated with treatment. Multicenter retrospective case series with patients who underwent a primary SLT procedure. A total of 835 eyes from 835 patients were included. The mean follow-up was 916.8 ± 563.0 days. The mean age was 64.5 ± 14.9 years and 56.6% were women. We observed an intraocular pressure reduction comparing baseline to post-SLT measurements (18.4 ± 3.8 mmHg versus 14.8 ± 3.5 mmHg; P < 0.001) and mean number of glaucoma medications (1.8 ± 1.3 versus 1.4 ± 1.4; P < 0.001). We observed visual acuity loss over time (0.1 ± 0.3 versus 0.2 ± 0.3 logMAR, baseline and post-SLT, respectively, P = 0.009) and decrease in visual field mean deviation values (- 5.4 ± 5.9 versus - 5.7 ± 6.0 dB; P = 0.054) The Kaplan-Meier survival analysis showed an estimated probability of treatment success of 88% at 12 months, declining to 70% at 24 months and 54% at 36 months post-SLT. In the multivariable model, we found that a denser angle pigmentation (HR 0.69; 95% CI 0.57-0.85, P = 0.001) and corticosteroid treatment following SLT (HR 0.59; 95% CI 0.39-0.91, P = 0.018) were significantly associated with a lower risk for failure. Primary SLT achieved relatively high success rates without sight-threating complications in this real-world study with a large sample of Brazilian patients. These findings corroborate previous studies regarding SLT outcomes and may help clinicians to identify the best candidates for laser treatment.

Safety and efficacy of arteriovenous fistula angioplasties performed by nephrologists: report from a Brazilian interventional nephrology center.

INTRODUCTION: Arteriovenous fistulas (AVF) are the first choice vascular access for hemodialysis. However, they present a high incidence of venous stenosis leading to thrombosis. Although training in interventional nephrology may improve accessibility for treatment of venous stenosis, there is limited data on the safety and efficacy of this approach performed by trained nephrologists in low-income and developing countries. METHODS: This study presents the retrospective results of AVF angioplasties performed by trained nephrologists in a Brazilian outpatient interventional nephrology center. The primary outcome was technical success rate (completion of the procedure with angioplasty of all stenoses) and secondary outcomes were complication rates and overall AVF patency. FINDINGS: Two hundred fifty-six angioplasties were performed in 160 AVF. The technical success rate was 88.77% and the main cause of technical failure was venous occlusion (10%). The incidence of complications was 13.67%, with only one patient needing hospitalization and four accesses lost due to the presence of hematomas and/or thrombosis. Grade 1 hematomas were the most frequent complication (8.2%). The overall patency found was 88.2 and 80.9% at 180 and 360 days after the procedure, respectively. CONCLUSION: Our findings suggest that AVF angioplasty performed by trained nephrologists has acceptable success rates and patency, with a low incidence of major complications as well as a low need for hospitalization.

Changes in circulating biomarkers during a single hemodialysis session.

The hemodialysis (HD) procedure induces an inflammatory response potentially contributing to cardiovascular disease. Here we investigated the acute impact of HD on circulating biomarkers. Circulating biomarkers (small solutes, middle molecular-sized peptides, and proteins) related to inflammation, oxidative stress, and vascular calcification (VC) were measured before and after a single session of HD in 45 clinically stable patients. Concentrations were corrected for ultrafiltration-induced hemoconcentration. Among vascular calcification-related biomarkers, osteoprotegerin and fetuin-A remained unchanged while fibroblast growth factor-23 (FGF23) decreased by -19%. Changes of FGF23 and changes of phosphate correlated (ρ = 0.61, P < 0.001). While C-reactive protein did not change, interleukin-6 (IL-6) increased by 14% and pentraxin 3 (PTX3) increased by 45%. IL-6 and PTX3 appear to be valid biomarkers of the intradialytic inflammatory response. VC-related markers were in general not affected by the single HD session; however, the observed correlation between acute changes of FGF-23 and phosphate during HD warrants further studies.

Effect of oral N-acetylcysteine treatment on plasma inflammatory and oxidative stress markers in peritoneal dialysis patients: a placebo-controlled study.

BACKGROUND: Inflammation and oxidative stress (OS) are cardiovascular risk factors in patients with chronic kidney disease. N-acetylcysteine (NAC) is a thiol-containing antioxidant with anti-inflammatory properties and has been shown to reduce the number of cardiovascular events in hemodialysis patients. METHODS: The current study aimed to determine the effect of oral NAC (2 x 600 mg/daily) on plasma levels of inflammatory and OS markers in peritoneal dialysis (PD) patients. We performed a placebo-controlled study over 8 weeks in 30 patients (40% males, age 52 +/- 13 years) on regular PD. Before the study was started, the patients were divided into 2 groups of 15 patients matched for age and gender. 22 patients completed the study (12 on NAC, 10 on placebo). Proinflammatory cytokines [high-sensitivity C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-alpha, and pentraxin 3] and markers of OS (pentosidine, advanced oxidation protein products, homocysteine, glutathione, asymmetric dimethylarginine, and free sulfhydryls) were measured before and after treatment with NAC. RESULTS: Treatment with NAC for 8 weeks increased mean baseline plasma NAC levels from 2.6 to 24.8 mumol/L (p = 0.007). This intervention, which caused no side effects, significantly diminished IL-6 levels, from 9.4 (4.5 - 31) to 7.6 (4.9 - 13.5) pg/mL (p = 0.006), whereas no such changes were observed in the placebo group. NAC treatment did not significantly affect the other inflammatory and OS markers. CONCLUSION: Short-term oral NAC treatment resulted in reduction of circulating IL-6, suggesting that such treatment could be a useful strategy in blunting the inflammatory response in PD patients.

Perfil de pacientes diabéticos em diálise / Profile of diabetic patients in dialysis

Introdução: Atualmente, diabetes mellitus (DM) representa a principal causa mundial de doença renal crônica. No Brasil, aproximadamente 25% dos pacientes em diálise são diabéticos. Objetivo: Este estudo visa a determinar as características clínicas e sociais dos pacientes diabéticos em diálise na cidade de Curitiba, Brasil. Materiais e Métodos: Estudo transversal realizado no período de março a agosto de 2006 na nossa instituição. Foram identificados 97 pacientes diabéticos (46% mulheres; média de 9,4 anos). As informações clínicas e socioeconômicas dos pacientes com idade de ± 58 anos foram obtidas por meio de questionário e revisão de prontuário. Resultados: Hipertensão arterial sistêmica (HAS) foi relatada por 75% dos pacientes e o tabagismo, em 25% das respostas. Renda familiar e nível de escolaridade baixos foram verificados em 85% dos pacientes (1 a 5 salários mínimos/mês). O diagnóstico de DM foi realizado por médico clínico geral em 86% dos casos, e o intervalo entre o diagnóstico de DM e a referência para o nefrologista foi maior que 10 anos (80%). Observou-se também que 48% e 70% dos pacientes em diálise já tinham avaliação prévia, por um endocrinologista e oftalmologista, respectivamente. Entretanto, somente 9% e 35% ainda mantêm acompanhamento regular com esses profissionais. Finalmente, 65% dos pacientes nunca receberam informações sobre cuidados do pé diabético. Conclusão: Diabéticos em diálise apresentam baixa escolaridade e maior prevalência de HAS. Além disso, o treinamento e acompanhamento de uma equipe multidisciplinar poderiam melhorar os cuidados dos pacientes diabéticos em diálise.

Introduction: Currently, diabetes mellitus (DM) represents the main cause of chronic disease worldwide. In Brazil, approximately 25% of dialysis patients are diabetic. Objective: This study was performed to determine the clinical and social characteristics in diabetic dialysis patients in the city of Curitiba, Brazil. Material and Methods: A cross-sectional study was carried out in our institution between March and August 2006. Ninety-seven diabetic (46% female: mean age 58 ± 9.4) patients were identified. Clinical and socialeconomic information was assessed through a questionnaire and by files review. Results: Systemic hypertension (High Blood Pressure HBP) was reported by 75% of patients, and smoking habit was present in 25% of the answers. Low income and low schooling were verified in 85% of the patients (between 1 and 5 minimal wage/month). Moreover, the DM diagnosis was performed by a general physician in 86% of the cases, and the interval between DM diagnosis and referral to the nephrologist was more than 10 years (80%). It has also been observed that 48% and 70% of the patients during dialysis had a previous evaluation by endocrinologist and ophthalmologist, respectively. However, only 9% and 35% of them are still being followed by these professionals regularly. Finally, 65% of the patients never received any information about diabetic foot care. Conclusion: Diabetic patients on dialysis have low income and schooling, with an increased prevalence of HBP. Moreover, management and training of a multiprofessional team could lead to an improvement in diabetes care in diabetic patients on regular dialysis.

Interleukin-6 is a better predictor of mortality as compared to C-reactive protein, homocysteine, pentosidine and advanced oxidation protein products in hemodialysis patients.

Inflammatory markers predict mortality in hemodialysis (HD) patients, whereas a possible association between oxidative stress (OS) markers and survival is less clear. We assessed the impact on all-cause mortality of baseline inflammatory [high-sensitivity C-reactive protein and interleukin-6 (IL-6)] and OS markers (advanced oxidation protein products, pentosidine, homocysteine) in 112 HD patients. We found no significant correlations between inflammatory and OS markers. During the 5.5 years of follow-up, 51 patients died. In a Kaplan-Meier analysis, the survival rate was reduced in patients with IL-6 higher than the median (IL-6 >4.2 pg/ml) (log- rank = 6.47; p = 0.01), in diabetics (log-rank = 12.26; p = 0.0005) and in older patients (log-rank = 11.22; p = 0.0008). Moreover, in Cox analysis only IL-6 and age were independently associated with mortality. We conclude that in this group of prevalent Brazilian HD patients, IL-6 was a better predictor of survival than other inflammatory and OS markers.

Stenosis in hemodialysis arteriovenous fistula: evaluation and treatment.

Vascular access complications are one of the main causes associated with an increase in morbidity and mortality in stage 5 chronic kidney disease patients. The arteriovenous fistula is regarded as the vascular access of choice for hemodialysis (HD) because of its superior patency and lower complication rates. Stenosis is considered the major cause of dysfunction of arteriovenous fistula. Despite the relatively low thrombosis rates of arteriovenous fistula, surveillance programs are necessary for detection of stenosis. We report a case of a HD patient who had never achieved an adequate Kt/V since the start of maintenance HD. During the investigation, abnormal findings were found on physical examination of the fistula, in addition to an alteration in intra-access pressure (IAP) measurements. A venous stenosis was diagnosed by Doppler ultrasound and then promptly treated with percutaneous transluminal angioplasty. The purpose of the discussion is to highlight the peculiarities of arteriovenous fistulae, methods of surveillance, including physical examination, IAP, recirculation, and measurements of blood flow, and the importance of the correction procedures for the stenosis.

Interventional nephrology in Brazil: current and future status.

The care of chronic kidney disease patients frequently involves many diagnostic and interventional procedures. Most of these procedures are currently performed by radiologists, vascular surgeons, and general surgeons. This has caused fragmented medical care, which has led many nephrologists to introduce a new paradigm, often referred as interventional nephrology (IN). The aim of this study was to establish the extent of involvement of the Brazilian nephrology community with regard to specific IN procedures. From October 2004 to February 2005, questionnaires were sent by e-mail to all 2500 nephrologists throughout Brazil. The enrollment questionnaire was composed of five sections, with questions about renal biopsy, specific training in ultrasonography, peritoneal dialysis access (insertion of peritoneal catheters guided or not by peritoneoscopy), hemodialysis vascular access (ability to place tunneled catheters, construction of arteriovenous fistulas, and other vascular access procedures), and the nephrologist's interest in being trained in IN. A total of 239 nephrologists answered the questionnaire. Only 18% of Brazilian nephrologists perform kidney biopsy guided by ultrasonography assisted by a radiologist. On the other hand, 42% of them reported that this procedure was done without any image support. Most of the respondents (85%) indicated that they were not formally trained to perform renal ultrasonography. When asked about peritoneal dialysis catheter placement, 66% of the respondents reported that they referred their patients to a surgeon for this procedure. The insertion of peritoneal dialysis catheters guided by peritoneoscopy was reported by 3% of the respondents. Similar to the results for peritoneal dialysis catheter placement, the majority of the respondents (77%) indicated no training in the insertion of tunneled catheters for temporary hemodialysis. Regarding the interest of nephrologists to participate in an IN program, the great majority (87%) responded that they would like to be trained in these procedures. Most nephrologists are not trained in IN procedures. Therefore, in Brazil, it will be necessary to develop training centers for IN that will allow nephrologists to optimize nephrology care.

Effect of high-dose thiamine and pyridoxine on advanced glycation end products and other oxidative stress markers in hemodialysis patients: a randomized placebo-controlled study.

OBJECTIVE: To study the effect of high doses of thiamine (250 mg/day) and pyridoxine (200 mg/day) supplementation on plasma levels of advanced glycation end products and other oxidative stress markers in hemodialysis patients. DESIGN: An interventional survey. SETTING: This study was conducted at an outpatient nephrology clinic. INTERVENTION AND PATIENTS: We performed a randomized placebo-controlled study over 8 weeks in 50 patients (53% men, age 52.9 +/- 3.4 years) on regular hemodialysis. MAIN OUTCOME MEASURES: The patients were divided into 2 groups of 25 patients in each arm. Before starting the study, the patients in both groups were matched by age, gender, inflammatory profile (plasma interleukin [IL]-6 and high-sensitivity C-reactive protein [hsCRP]), and nutritional status (subjective global assessment and protein nitrogen appearance). RESULTS: In all, 40 of 50 patients completed the study (19 patients in the vitamin group and 21 in the placebo group). Serum albumin, plasma hsCRP, IL-6, advanced oxidation protein products, pentosidine and 8-hydroxy-2'-deoxyguanosine were measured before and after treatment in each group. In both groups, over 8 weeks of follow-up, no significant differences could be observed in oxidative stress, inflammatory, or nutritional markers. CONCLUSIONS: There was no evidence showing that high doses of thiamine and pyridoxine affects oxidative stress in hemodialysis patients.

The prognostic impact of fluctuating levels of C-reactive protein in Brazilian haemodialysis patients: a prospective study.

BACKGROUND: A single elevated C-reactive protein (CRP) value predicts mortality in haemodialysis (HD) patients, but the relative importance of repeated vs occasional positive systemic inflammatory response findings is not known. METHODS: To assess the influence on survival of occasional inflammation, CRP, serum albumin (S-Alb) and fibrinogen were analysed bimonthly in 180 HD patients (54% male, 49+/-14 years). Clinically significant inflammation was defined as CRP >5.1 mg/l, based on the receiver operating characteristics curve for CRP as predictor of death. Based on four consecutive measurements of CRP, patients were assigned into three groups: group 1 (n = 74; 41%), no inflammation (CRP < or = 5.1 mg/l in all measurements); group 2 (n = 65; 36%), occasional inflammation (1-3 measurements of CRP > 5.1 mg/l); and group 3 (n = 41; 23%), persistent inflammation (all measurements of CRP >5.1 mg/l). The nutritional status was evaluated by subjective global assessment (SGA) and body mass index (BMI), and the survival (21 months of follow-up) by Kaplan-Meier curve and Cox model. RESULTS: The median and range of CRP values (mg/l) for group 1, 2 and 3 were: 3.2 (3.2-5.1), 3.6 (3.2-54.9) and 13.8 (5.2-82), respectively (P<0.001), whereas the prevalence of malnutrition, assessed by SGA and BMI, did not differ significantly between the groups. The survival rate by Kaplan-Meier analysis was significantly different among the groups (chi2 = 12.34; P = 0.0004). Patients in group 3 showed the highest mortality (34%; P = 0.001), compared with group 1 (8%) and group 2 (14%; P = 0.01), respectively, whereas there was no significant difference in mortality between groups 1 and 2. Age, CRP, S-Alb level and SGA were independent predictors of mortality. CONCLUSION: The patients with a persistent elevation of CRP had a higher mortality rate than the patients with occasional CRP elevation. Thus, persistent, rather than occasional, inflammation is an important predictor of death in HD patients.

The influence of hepatitis C and iron replacement therapy on plasma pentosidine levels in haemodialysis patients.

BACKGROUND: Chronic liver disease and intravenous (i.v.) iron therapy can enhance oxidative stress. The aim of this study was to assess the influence of hepatitis C virus (HCV) and i.v. iron administration on oxidative stress in chronic haemodialysis (HD) patients. METHODS: A total of 115 HD patients (47% males, age 47 +/- 13 years) were placed in two groups according to the presence (HCV(+)) or absence (HCV(-)) of serum antibodies against HCV. Plasma pentosidine, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and alanine aminotransferase (ALT) levels were measured. The patients were also analysed according to the tertiles of serum levels of ferritin: group 1 (ferritin <380 ng/ml), group 2 (ferritin 380-750 ng/ml) and group 3 (ferritin >750 ng/ml). The cumulative iron dose was recorded during 6 months prior to the study. RESULTS: HCV(+) patients had significantly higher levels of plasma pentosidine and ALT than HCV(-) patients. Age, gender, serum albumin, IL-6 and hsCRP did not differ according to HCV serology. The levels of pentosidine were related to the ferritin levels and were significantly higher in group 3 compared with group 1. Moreover, the cumulative dose of iron was significantly higher in group 3 than in group 1. Plasma pentosidine showed a positive correlation with age, HCV and ferritin. In a stepwise backward multiple regression model, age and HCV were independent predictors of pentosidine levels. CONCLUSION: HCV in HD patients is associated with increased pentosidine levels, possibly reflecting increased oxidative stress. The association between pentosidine and ferritin levels may suggest an impact of i.v. iron therapy.

The recommendations from the International Society for Peritoneal Dialysis for Peritonitis Treatment: a single-center historical comparison.

The antibiotic treatment currently recommended by the International Society for Peritoneal Dialysis (ISPD) for peritonitis consists of a combination of a first- and a third-generation cephalosporin. The schedule formerly recommended combined a first-generation cephalosporin and an aminoglycoside. No comparison between the treatment schedules has been performed until now. We compared the effectiveness of these two regimens in peritoneal dialysis-related peritonitis at our center. From January 1999 to April 2000, we followed 107 patients in our PD clinic (period 1: 47% men; 32% with diabetes; mean age: 52 +/- 13 years). We followed a similar number of patients from January 2002 to July 2003 (period 2: 109 patients; 54% men; 51% with diabetes; mean age: 56 +/- 18 years). In each period, diagnosis and treatment of peritonitis were based on the recommendations of the ISPD as earlier described. Negative culture rates were similar in period 1 and period 2 (32% vs. 30%). In both study groups, the bacteria that most commonly caused peritonitis were Staphylococcus epidermidis (period 1: 41%; period 2: 39%) and S. aureus (period 1: 27%; period 2: 18%). Gram-positive infections occurred in 59% of patients during period 1 and in 57% during period 2. Gram-negative infections occurred in 16% of patients during period 1 and in 18% during period 2. We observed no significant difference in the peritonitis cure rate from period 1 to period 2 (78% vs. 83%; chi-square: 0.98; p = 0.3), but changes in the primary antibiotic schedule were necessary in 4 patients in period 1 as compared with 1 patient in period 2. The rates of catheter removal were not significantly different during the two periods (period 1: 14%; period 2: 5%; chi-square: 2.5; p = 0.11). Mortality was also not significantly different during the two periods (period 1: 7%; period 2: 5%; chi-square: 0.23; p = 0.62). The two antibiotic schedules were equally effective in the treatment of peritonitis. Cost-effectiveness, impact on residual renal function, and potential development of bacterial resistance must be considered when selecting the antibiotic schedule for peritonitis treatment.

Inflammation, malnutrition and atherosclerosis in end-stage renal disease: a global perspective.

End-stage renal disease (ESRD) is characterized by an exceptional cardiovascular mortality rate. Although traditional risk factors are common in ESRD patients, they alone may not be sufficient to account for the high prevalence of cardiovascular disease (CVD). Recent evidence demonstrated that chronic inflammation, a non-traditional risk factor which is commonly observed in ESRD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. Although both malnutrition and inflammation have been shown to be strong predictors of cardiovascular mortality in ESRD patients, it must be remembered that the majority of studies describing the presence of inflammation and malnutrition have been performed in Western and Asian industrialized countries. As it is evident that the prevalence of malnutrition and inflammation may differ markedly between different regions of the world and developing countries face a much higher prevalence of chronic infectious diseases, comparative inter-regional studies focusing on the etiology and prevalence of the malnutrition, inflammation and atherosclerosis syndrome are warranted.

Relato de caso: biópsia renal por via transjugular / Relate of case: Renal biopsy through transjugular way

A realizaçäo de biópsia renal por via percutânea nem sempre é possível, especialmente na vigência de distúrbio de coagulaçäo significativo. Em novembro de 1997, no Hospital Universitário Evangélico de Curitiba, foi realizada uma biópsia renal por via tranjugular (VT) em uma paciente com suspeita de mieloma múltiplo que apresentava-se com um quadro de insuficiência renal e plaquetopenia (contagem de 30.000 plaquetas/mm3).O procedimento mostrou-se seguro, näo apresentando complicaçöes pós-biópsia e obtendo-se dois fragmentos com seis glomérulos em cada amostra, os quais possibilitaram o diagnóstico de "rim do mieloma". A biópsia por VTJ mousto-se um método seguro e eficaz quando da impossibilidde da realizaçäo desse procedimento por via percutânea