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.

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.

Bone Marrow Adiposity in Premenopausal Women With Type 2 Diabetes With Observations on Peri-Trabecular Adipocytes.

CONTEXT: No study has yet evaluated the relationships among bone marrow adiposity (BMA), bone histomorphometry (BH), and glycemic control in premenopausal women with type 2 diabetes (T2DM). OBJECTIVE: We aimed to assess the effect of glycemic control on BMA, correlate the parameters of BH with BMA, and correlate BMA with the use of hypoglycemic agents and with bone mineral density (BMD). METHODS: This was a cross-sectional study that evaluated 26 premenopausal women with T2DM who were divided into groups with HbA1c < 7% (good control [GC], n = 10) and HbA1c > 7% (poor control [PC], n = 16). BMA parameters (adipocyte number [Ad.N], total adipocyte perimeter [Ad.Pm], total adipocyte area [Ad.Ar], percentage adipocyte volume per marrow volume [Ad.V/Ma.V]) and peri-trabecular adipocyte number divided by bone surface (Ad.N/BS) were evaluated. BH static (bone volume fraction [BV/TV], osteoid thickness [O.Th], osteoid surface/bone surface [OS/BS]) and dynamic parameters and serum insulin-like growth factor-1 were measured. BMA data were compared between the GC and PC groups. Correlations were performed. RESULTS: Ad.N, Ad.Pm, and Ad.Ar were higher in PC (all, P = 0.04). HbA1c correlated positively with Ad.N/BS (P < 0.01) and Ad.N/BS correlated negatively with O.Th (P < 0.01) and OS/BS (P = 0.02). Positive and negative correlations were observed between insulin and metformin use, respectively, with all adipocyte parameters except Ad.N/BS (P < 0.05). Structural parameters were negatively correlated with the BMA. BMD of the femoral neck (r = -549, P < 0.01) and total femur (r = -0.502, P < 0.01) were negatively correlated with Ad.V/Ma.V. CONCLUSION: Poor glycemic control is associated with hyperplasia and hypertrophy of BMAs and with lower BV/TV. Ad.N/BS, a new BMA parameter, is correlated with HbA1c and negatively with O.Th. The use of insulin seems to stimulate the expansion of BMA while that of metformin has the opposite effect. These findings suggest that the increase in BMA may play a role in the T2DM bone disease; on the other hand, good glycemic control might help prevent it.

Bone Histomorphometry in Young Patients With Type 2 Diabetes is Affected by Disease Control and Chronic Complications.

CONTEXT: Type 2 diabetes mellitus (T2DM) is associated with an increased risk of fractures. No study has evaluated the correlation of bone histomorphometry (BH) parameters with glycemic control and presence of chronic complications (CCs) in premenopausal women with T2DM. OBJECTIVES: To evaluate BH and correlate them with the degree of glycemic control and presence of CCs. DESIGN, SETTINGS, AND PATIENTS: This was a cross-sectional study conducted at a tertiary medical center. Twenty-six premenopausal women with T2DM were divided into groups with glycated hemoglobin HbA1c < 7% (good control, GC; n = 10) and HbA1c > 7% (poor control, PC; n = 16), and further subdivided into groups with (n = 9) and without (n = 17) CCs. BH parameters (bone volume [bone volume per total volume, BV/TV], trabecular thickness [Tb.Th], trabecular number [Tb.N], trabecular separation [Tb.Sp], osteoid thickness [O.Th], osteoid surface [osteoid surface per bone surface, OS/BS]), mineralizing surface [MS/BS], bone formation rate [BFR]), mineral apposition rate [MAR]) as well as serum pentosidine (PEN) and insulin-like growth factor (IGF)-1 were measured. The BH data were compared among the groups and with a BH control group (control group, CG, n = 15) matched by age, sex, and race. RESULTS: BV/TV was increased in GC (P < .001) and PC (P = .05) groups and O.th (P = .03) was smaller in the PC group than in the CG. A comparison of the groups with and without CCs with the CG showed in the group with CCs, O.Th was smaller(P = .01) and BV/TV similar to the CG (P = .11). HbA1c correlated negatively with O.Th (P = .02) and OS/BS (P = .01). There was no correlation of BH to PEN and IGF-1. CONCLUSION: BH in premenopausal patients with T2DM is affected by disease control and chronic complications.

Peritoneal dialysis access: what's the best approach?

There are many procedures for placement of an intraabdominal peritoneal catheter for peritoneal dialysis. Each one has its own advantages and disadvantages. Although the blind technique with a trocar was the initial procedure utilized, over the years interventional nephrologists and surgeons have evolved to more modern techniques that allow more direct visualization of the peritoneal cavity, minimizing complications catheter-related. Novel techniques such as peritoneoscopy and laparoscopy appear to be associated with a reduced number of exit site infections, lower incidence of peritonitis, decreased risk of leakage and improved catheter survival. Since some studies have not seen all these benefits associated with these procedures, one recognizes the importance of the experience obtained with each procedure in every center and the impossibility of generalization.

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.