Vascular access in hemodialysis patients older than 80 years.

OBJECTIVE: There is a worldwide surge in numbers of elderly people requiring hemodialysis accompanying the prevailing increase in longevity. There is a trend for central venous catheters to be preferentially placed in elderly patients, whereas others recommend routine use of grafts for surgical access. In our center, age has not been a consideration in deciding to construct arteriovenous access for hemodialysis. We reviewed our experience with arteriovenous access surgery in all hemodialysis patients aged 80 years and older to determine if this approach is justified in terms of patency and life expectancy. METHODS: A retrospective study was made of all patients aged 80 years and older who had surgery from January 2005 to December 2009 at our national vascular access referral center. All patients had preoperative mapping and had fistula construction if the vein size was at least 3 mm. Otherwise they had brachiobasilic or brachioaxillary grafts. All patients had routine access surveillance by Doppler ultrasound (duplex) and physical examination at regular intervals, and interventions were carried out according to the findings. Type of access, success rate, maturation, primary and secondary patency, and patient survival in the age group older than 80 years were noted. RESULTS: During the study period, 134 patients had 146 new accesses. There were 128 autogenous accesses (30 forearm, 91 upper arm, and seven transposed basilic veins) and 18 prosthetic accesses. Overall primary patency was 39%, 33%, and 23% at 12, 24, and 36 months. Secondary patency was 92%, 83%, and 77% at 12, 24, and 36 months. There was no significant difference in patency between the different types of accesses and between diabetic and nondiabetic patients. Eleven upper arm and four forearm fistulas had delayed maturation or nonmaturation. The relative risk for delayed maturation or nonmaturation of forearm fistulas (13.3%) compared with brachial-cephalic fistula (12.1%) was 1.1030 (95% confidence interval, 0.3973-3.204; P = .8571). Median patient survival was 38 months, with 49 dying during follow-up. CONCLUSIONS: Contrary to recent recommendations favoring grafts for hemodialysis in patients older than 80 years, most elderly patients in this study were found to have vasculature that was suitable for autogenous access construction, with patency rates similar to those of their younger counterparts when adequate preoperative planning and postoperative maintenance were carried out. Age alone should not disqualify patients older than 80 years from access surgery for hemodialysis, nor should age disqualify these patients from the Fistula First Initiative.

A prospective randomized study of heparin-bonded graft (Propaten) versus standard graft in prosthetic arteriovenous access.

OBJECTIVE: Prosthetic grafts continue to be required for hemodialysis access when the options for native fistulas have been exhausted. The inferior long-term patency of grafts makes the possibility of preventing occlusion with heparin-bonded grafts an attractive alternative. We carried out a prospective randomized study to compare the patency of standard grafts with heparin-bonded grafts. METHODS: Patients with end-stage renal failure requiring a prosthetic access were randomized to receive either a standard expanded polytetrafluorethylene (ePTFE) graft or a heparin-bonded ePTFE graft. Patients were enrolled from June 2007 until November 2011 and were followed up until July 2013, when the study concluded. RESULTS: In this study, 160 patients were randomized and followed up for a median of 23.5 months. No patient was lost to follow-up. Primary patency was 35% and 14% for heparin-bonded grafts and 29% and 12% for standard ePTFE grafts at 6 and 12 months, respectively (P = .48). Assisted primary patency was 54%, 41%, and 27% for heparin-bonded grafts and 41%, 30%, and 23% for standard grafts at 12, 24, and 36 months, respectively (P = .12). Secondary patency was 83%, 83%, and 81% for heparin-bonded grafts and 81%, 73%, and 68% for standard grafts at 12, 24, and 36 months, respectively (P = .33). There were significantly fewer thromboses in heparin-bonded grafts during the first 5 months (P = .020). Of 80 standard grafts, 24 were eventually abandoned vs 17 heparin-bonded grafts (P = .188). Bleeding complications, infections, and intervention rates were similar in both groups. CONCLUSIONS: Heparin-bonded grafts demonstrated a trend to improved patency, but the difference was not statistically significant. Heparin-bonded grafts had a significantly lower early thrombosis rate that was sustained only for the first 5 months of follow-up.

Nephrology Partnership for Advancing Technology in Healthcare (N-PATH) program: the teachers' perspective.

The N-PATH (Nephrology Partnership for Advancing Technology in Healthcare) program concluded with the 60th European Renal Association 2023 Congress in Milan, Italy. This collaborative initiative aimed to provide advanced training in interventional nephrology to young European nephrologists. Funded by Erasmus+ Knowledge Alliance, N-PATH addressed the global burden of chronic kidney disease (CKD) and the shortage of nephrologists. CKD affects >850 million people worldwide, yet nephrology struggles to attract medical talent, leading to unfilled positions in residency programs. To address this, N-PATH focused on enhancing nephrology education through four specialized modules: renal expert in renal pathology (ReMAP), renal expert in vascular access (ReVAC), renal expert in medical ultrasound (ReMUS) and renal expert in peritoneal dialysis (RePED). ReMAP emphasized the importance of kidney biopsy in nephrology diagnosis and treatment, providing theoretical knowledge and hands-on training. ReVAC centred on vascular access in haemodialysis, teaching trainees about different access types, placement techniques and managing complications. ReMUS recognized the significance of ultrasound in nephrology, promoting interdisciplinary collaboration and preparing nephrologists for comprehensive patient care. RePED addressed chronic peritoneal dialysis, offering comprehensive training in patient selection, prescription, monitoring, complications and surgical techniques for catheter insertion. Overall, N-PATH's strategy involved collaborative networks, hands-on training, mentorship, an interdisciplinary approach and the integration of emerging technologies. By bridging the gap between theoretical knowledge and practical skills, N-PATH aimed to revitalize interest in nephrology and prepare proficient nephrologists to tackle the challenges of kidney diseases. In conclusion, the N-PATH program aimed to address the shortage of nephrologists and improve the quality of nephrology care in Europe. By providing specialized training, fostering collaboration and promoting patient-centred care, N-PATH aimed to inspire future nephrology professionals to meet the growing healthcare demands related to kidney diseases and elevate the specialty's status within the medical community.

Stent grafts for central venous occlusive disease in patients with ipsilateral hemodialysis access.

PURPOSE: To assess long-term outcomes of stent grafts in patients with symptomatic central venous stenoses and occlusions ipsilateral to hemodialysis grafts or fistulas. MATERIALS AND METHODS: The study included 52 of 55 consecutive patients with symptomatic stenoses of the central veins draining upper limb dialysis access grafts or fistulas treated with stent grafts. Indications for stent grafts were poor angioplasty results, rapid recurrence, or total occlusion. Endpoints were lesion patency and access patency following intervention. Mean follow-up was 25 months with a median of 24 months and 1.25 additional procedures per patient year. Patency rates were calculated using Kaplan-Meier analysis. RESULTS: All stent grafts were successfully deployed. The lesion patency rates at 6, 12, 24, and 36 months after intervention were 60%, 40%, 28%, and 28%. The access patency rates at 6, 12, 24, and 36 months after intervention were 96%, 94%, 85%, and 72%. There was one major complication and no minor complications. In 40 patients (77%), the internal jugular vein confluence was covered by the stent graft. In five patients, the dialysis circuits became occluded, with no clinical sequelae in four; one patient was lost to follow-up. The contralateral brachiocephalic vein was covered in three patients (6%), preventing contralateral access construction in one patient. CONCLUSIONS: Central vein stent graft placement in patients with hemodialysis access is associated with prolonged access patency. Coverage of major vein confluences, which occurred in 83% of the patients in this series, can compromise future access and should be avoided whenever possible by careful technique.

Single probe light reflectance spectroscopy and parameter spectrum feature extraction in experimental skin cancer detection and classification.

Skin cancer, an anomalous development of skin cells in the epidermis, is among the most common types of cancer worldwide. Because of its clinical importance and to improve early diagnosis and patient management, there is an urgent need to develop noninvasive, accurate medical diagnostic tools. To this aim, light reflectance spectroscopy over the visible and near-infrared spectral range (400-1000 nm) based on a single-fiber six-around-one optical probe was applied to extract nine features used for diagnostics. These features include skewness, entropy, energy, kurtosis, scattering amplitude, and others, and are spread over each of four different spectral signatures, namely, light reflectance, absorbance, scattering profile approximation, and absorption/scattering ratio. Our preliminary studies focused on 11 adult patients with diagnoses of malignant melanoma (n = 4), basal cell carcinoma (n = 5), and squamous cell carcinoma (n = 2) in a variety of locations on the body. Measurements were taken first in vivo before surgery, at the site of the lesion and from healthy skin of the same patient, and ex vivo after surgical excision, where the lesion was rinsed in saline solution and measurements of the reflected light from the "inside" facing plane of the tissue were taken in the same manner. Overall, experimental results demonstrate that by examining a variety of wavebands, features, and statistical metrics, we can detect and distinguish cancer from normal tissue and different cancer subtypes. Nevertheless, discrepancies in results between in vivo and ex vivo tissue were observed and explanations for these discrepancies are discussed.

Ipsilateral hemodialysis access after axillary dissection for breast cancer.

Breast cancer survivors who have had axillary lymph node dissection (ALND) and who later develop end-stage renal failure may eventually require hemodialysis access. If veins available for access in the contralateral arm have been exhausted, especially after chemotherapy, the ipsilateral arm will have to be considered for access construction. There are no evidence-based guidelines for lymphedema prevention, but there are sweeping recommendations to avoid physical injury to the ipsilateral limb, including needle puncture, after ALND with or without radiotherapy. Three studies have shown little or no effect of hand surgery in producing or exacerbating lymphedema after ALND. Dialysis access guidelines recommend the use of autogenous accesses over synthetic grafts whenever possible. Three patients after ALND were referred for hemodialysis access construction in our center. Pre-operative duplex ultrasound confirmed that patent veins appropriate for autogenous access construction were only present in the ipsilateral arm. Autogenous arteriovenous fistulas were constructed in the ipsilateral arm in the three patients. All the three entered our access surveillance program and were regularly examined. All had more than 20 lymph nodes removed. One had axillary radiotherapy and anthracycline-based chemotherapy, one had anthracycline-based chemotherapy without axillary radiotherapy and one had neither treatment. The access was established 4-10 years after ALND. No patient developed significant lymphedema at two, 20 and 76 months respectively after access construction, with cannulation for dialysis occurring three times a week. Autogenous hemodialysis access construction does not seem to contribute to lymphedema development after ALND. Physicians and other medical personnel caring for patients with breast cancer should not oppose the use of the ipsilateral arm if it is the only arm with vasculature suitable for autogenous access construction. Recommendations for lymphedema prevention may exaggerate the extent of risk attributable to interventions in the ipsilateral arm.

Resection margins in ultrasound-guided breast-conserving surgery.

BACKGROUND: Few published studies have shown the benefits of intraoperative ultrasound in avoiding inadequate margins in breast-conserving surgery. The aim of this study is to quantify intraoperative ultrasound margin size and assess its relationship to tumor size, multifocality, palpability, histology, and presence of intraductal component. METHODS: Patients with breast cancer undergoing breast-conserving surgery in whom the operating surgeon visualized the tumor by ultrasound were included. Ultrasound margins measured intraoperatively were prospectively recorded and compared with pathology margins. RESULTS: Forty-five patients with 48 tumors were included. Twenty five patients (56%) had palpable tumors. Pathologic mean tumor size was 1.9 cm [95% confidence interval (CI) 1.6-2.2 cm, range 0.5-4.8 cm]. There was good correlation between closest margins recorded by ultrasound and pathology margins (r = 0.4674, P < 0.0008). Fourteen patients (31%) had margins re-excised intraoperatively, 12 of them in the direction of the closest pathological margin. Three patients (7%), all of whom had intraoperative re-excision, had a second operation for involved margins without residual cancer on pathological examination of the reoperative specimens. Ultrasound margins ≥0.5 cm achieved adequate pathology margins of ≥0.2 cm in 95% of margins. Overestimation of pathology margins by ultrasound measurement was significantly affected by multifocality (P = 0.0473). Tumor size, palpability, invasive lobular histology, and presence of ductal carcinoma in situ (DCIS) did not cause significant overestimation of pathology margins by ultrasound. CONCLUSIONS: Intraoperative ultrasound may help maintain a low level of reoperation after breast-conserving surgery. Ultrasound margins <0.5 cm should be re-excised intraoperatively. Reliability of ultrasound in predicting the closest pathology margins was diminished in patients with multifocal tumors.

Stent graft treatment for hemodialysis access aneurysms.

BACKGROUND: Aneurysms that develop in arteriovenous accesses as a result of repeated punctures are sometimes complicated by infection or ischemia causing sloughing of the overlying skin, which may endanger the access and risk major bleeding and other complications. Surgical revision may necessitate the temporary use of a central venous catheter until dialysis can be resumed via the access. We used stent grafts in selected patients for the exclusion of access aneurysms. METHODS: Twenty of 63 patients requiring access revision for complication of an aneurysm from February 2005 to December 2009 underwent ambulatory endovascular stent graft deployment. Indications included signs of impending rupture, questionable viability of overlying skin, pain, infection, and limitation of cannulation sites by the size or number of the aneurysms. Endovascular treatment always included angioplasty of associated outflow or central vein stenoses at the same ambulatory session. RESULTS: Twenty patients with complicated access aneurysms were treated by endovascular stent graft exclusion at an average of 4.8 ± 4.3 years (range, 0.2 to 16.1 years) after access construction: nine graft pseudoaneurysms, nine native vein aneurysms, and two acute iatrogenic pseudoaneurysms. Six patients had skin erosion over the aneurysm, and 12 had painful aneurysms and clinical signs of compromised blood supply to the skin. Another two patients with an acute giant false aneurysm occurring during endovascular procedures were treated in the same interventional session by the stenting technique to control bleeding. All the aneurysms underwent endovascular exclusion without complications. Only one infected puncture site failed to heal within 2 months of stenting and was closed surgically 10 months later due to persistent localized graft infection, but with no further bleeding episodes. Only one aneurysm did not reabsorb within 3 months. Patients with painful skin ischemia had immediate pain relief. All patients also had stenosis in the draining veins necessitating additional percutaneous transluminal angioplasty. Only one patient required hospitalization (for intravenous antibiotic treatment of staphylococcal sepsis). No patients required a central catheter for hemodialysis. One access occluded due to cephalic arch stenosis in a noncompliant patient. Functional patency was 87% at 12 months, with a median follow-up of 15 months (range, 6.3 to 55.5 months). CONCLUSION: Endovascular treatment with stent grafts in complicated access aneurysms is a simple, safe and rapid ambulatory procedure that enables treatment of both the aneurysm and its accompanying draining vein stenosis. It enables continued cannulation of the existing access and avoids the use of central catheters.

Single probe diffuse reflectance spectroscopy to assess the effect of sarcopoterium spinosum treatment on the cerebral tissue properties of ApoE knockout mouse.

In this work, diffuse near-infrared light reflectance spectroscopy based on a single optical probe, contains central single collection fiber surrounded by a circular array of illumination fibers, was used to quantify cerebral tissue properties in ApoE knockout mice following Sarcopoterium spinosum treatment. Sarcopoterium spinosum, also known as Thorny burnet, is a Mediterranean plant widely used as a traditional therapy for the treatment of a variety of pathologies, primarily type 2 diabetes mellitus (T2D). While it's efficacy in the treatment of T2D, and of other components of metabolic syndrome, have already been validated by us, the aim of this study was to investigate the effects of Sarcopoterium spinosum extract (SSE) on dyslipidemia and vascular functions. We utilized ApoE deficient mice (ApoE-/- , Atherosclerosis-prone apolipoprotein E-deficient), who have a severe impairment in plasma lipoprotein clearance and thus develop alterations in blood lipid profile and are highly susceptible to atherogenic plaque formation. A total of 34 male mice were divided into five groups representing various genetic, dietary, and treatment configurations. Optical measurements were used to assess changes in diffused reflectance spectra, optical properties (absorption and scattering), and cerebral tissue chromophore contents. Specifically, significant improvement in cerebral hemoglobin level was observed in ApoE KO mice, fed an artherogenic diet (ATD), upon SSE treatment. Biochemical and histological analyses of ApoE-/- ATD mice showed elevated body weight and a high level of blood triglycerides, free fatty acids and cholesterol. In contrast, in SSE treated mice improvement was observed, suggesting beneficial effects of SSE. In ApoE-/- ATD mice group a higher levels of deoxyhemoglobin was monitored indicating that the rate of oxygen release to the tissue is low. This was supported by decrease in oxygen saturation. It was also shown a reduction in water content in the brain of ApoE KO. Mice fed with the atherogenic diet demonstrated increased water content as compared to STD-fed ApoE KO mice, while SSE administration reversed the effect of the diet. To our knowledge, no such study has been reported before.

Carpal tunnel syndrome in patients with arteriovenous fistula for haemodialysis: A narrative review of the current literature.

The ideal choice of vascular access in patients requiring haemodialysis is an arteriovenous fistula. However, an important often under-reported complication encountered at follow-up is symptoms of tingling or numbness in the hand. This may represent carpal tunnel syndrome, impairment of the median nerve as it traverses through the carpal tunnel at the wrist by focal compression of this nerve. Contributory factors in the presence of an arteriovenous fistula may include venous hypertension and varying steal syndrome phenomena provoking micro-ischaemia. Studies that investigated the evolution of carpal tunnel syndrome in haemodialysis patients with an arteriovenous fistula revealed that the frequency of carpal tunnel syndrome associated with an arteriovenous fistula on haemodialysis ranged from 10.4% to 42.6%. An association between duration of haemodialysis with arteriovenous fistula and carpal tunnel syndrome development was also observed. Surgical release of carpal tunnel provided complete relief of paraesthesia in all treated patients in the examined, demonstrating an alleviation of symptoms and improved function of hand and quality of life in patients with an arteriovenous fistula. However, the aetiology and risk factors for development of carpal tunnel syndrome remain unclear and further studies should attempt to elucidate the pathophysiology of this occurrence in the presence of arteriovenous fistulas.

Banding between dialysis puncture sites to treat severe ischemic steal syndrome in low flow autogenous arteriovenous access.

Dialysis-associated steal syndrome with rest pain and ischemic nonhealing ulcers dictates prompt surgical intervention. Distal revascularization with interval ligation is extensive surgery for frail patients in whom calcified distal arteries make anastomosis difficult. Simple banding is appropriate in high-flow fistulas. In low-flow accesses, further flow reduction by simple banding may result in inadequate dialysis and cause thrombosis. However, banding between puncture sites maintains a pressure gradient between the arterial and venous puncture sites that enables adequate flow with effective hemodialysis that would not be possible with banding at the anastomosis. This new technique is a good solution for maintaining access patency and increasing digital pressure while avoiding complicated surgical revisions in high-risk patients.

A comprehensive study of cardiovascular risk factors, cardiac function and vascular disease in children with chronic renal failure.

BACKGROUND: Cardiovascular disease causes major morbidity and is an important determinant of premature death in the paediatric chronic kidney disease (CKD) population. It is composed of three separate, although interrelated, disease processes: atherosclerosis, arteriosclerosis (i.e. medial vascular calcifications) and myocardial disease. Myocardial consequences of atherosclerosis barely exist in children, thus providing a good opportunity to investigate the role that kidney disease plays in the development of cardiovascular disease. METHODS: We assessed 70 patients, aged 4 months to 18 years, with chronic kidney disease stages 3-5, for known risk factors of cardiovascular disease and for additional laboratory and clinical variables which may have an impact on this disease process. Carotid artery ultrasound was used to evaluate vascular structure and function, whereas myocardial disease was assessed by echocardiography. RESULTS: Traditional risk factors, although present in this cohort, did not accumulate with progression of chronic kidney disease. Non-traditional risk factors increased in number and severity in correlation with the stage of CKD. The main myocardial abnormalities were left ventricular hypertrophy and diastolic dysfunction. Vascular function tests correlated with calcium-phosphate metabolism variables, homocysteine and time-averaged serum uric acid. CONCLUSIONS: This study shows that children with CKD are exposed to risk factors and demonstrate signs of cardiovascular disease already at a young age. The possible role of uric acid and homocysteine in the evolution of cardiovascular disease is discussed. Further studies looking at possible interventions to prevent cardiovascular morbidity and mortality in this high risk population are needed.

Decreased cerebral blood flow and hemodynamic parameters during acute hyperglycemia in mice model observed by dual-wavelength speckle imaging.

In this study, we use dual-wavelength optical imaging-based laser speckle technique to assess cerebral blood flow and metabolic parameters in a mouse model of acute hyperglycemia (high blood glucose). The effect of acute glucose levels on physiological processes has been extensively described in multiple organ systems such as retina, kidney, and others. We postulated that hyperglycemia also alters brain function, which in turn can be monitored optically using dual-wavelength laser speckle imaging (DW-LSI) platform. DW-LSI is a wide-field, noncontact optical imaging modality that integrates the principles of laser flowmetry and oximetry to obtain macroscopic information such as hemoglobin concentration and blood flow. A total of eight mice (C57/BL6) were used, randomized into two groups of normoglycemia (control, n = 3) and hyperglycemia (n = 5). Hyperglycemia was induced by intraperitoneal injection of a commonly used anesthetic drug combining ketamine and xylazine (KX combo). We found that this KX combo increases blood glucose (BG) levels from 150 to 350 mg/dL, approximately, when measured 18 minutes post-administration. BG continues to increase throughout the test period, with BG reaching an average of 463 ± 20.34 mg/dL within 60 minutes. BG levels were measured every 10 minutes from tail blood using commercially available glucometer. Experimental results demonstrated reductions in cerebral blood flow (CBF) by 55%, tissue oxygen saturation (SO2 ) by 15%, and cerebral metabolic rate of oxygen (CMRO2 ) by 75% following acute hyperglycemia. The observed decrease in these parameters was consistent with results reported in the literature, measured by a variety of experimental techniques. Measurements with laser Doppler flowmetry (LDF) were also performed which confirmed a reduction in CBF following acute hyperglycemia. In summary, our findings indicate that acute hyperglycemia modified brain hemodynamic response and induced significant changes in blood flow and metabolism. As far as we are aware, the implementation of the DW-LSI to monitor brain hemodynamic and metabolic response to acute hyperglycemia in intact mouse brain has not been previously reported.

Angioplasty with stent graft versus bare stent for recurrent cephalic arch stenosis in autogenous arteriovenous access for hemodialysis: a prospective randomized clinical trial.

BACKGROUND: Early recurrent stenosis of the cephalic arch in autogenous arteriovenous access for hemodialysis is a common problem that requires stenting to prevent thrombosis. Because the results of stenting are unsatisfactory, we compared the efficacy of stent grafts with bare stents in these patients. METHODS: All patients who presented with recurrent cephalic arch stenosis >50% within 3 months of successful balloon angioplasty were randomized to have angioplasty and stenting with either a bare nitinol stent or a stent graft. Outcome was assessed by angiography 3 months later. Restenosis was defined as >50% narrowing of the stent lumen or of the vessel margin up to 0.5 cm adjacent to the stent. There were no exclusions. RESULTS: This report includes data on the outcome of 25 consecutive patients with recurrent cephalic arch stenosis who were treated from April to August 2006. At 3 months, three patients had died and one had undergone a renal transplant. The 21 patients who had angiography at 3 months had patent stents. Restenosis rates were seven of 10 (70%) in the bare stent group and two of 11 (18%) in the stent graft group (P = .024). Life-table analysis at 3 and 6 months showed that primary patency was 82% in the stent graft group and 39% in the bare stent group. One-year primary patency was 32% in the stent graft group and 0% in the bare stent group (P = .0023). During a mean follow-up of 13.7 months, nine patients died, four in the bare stent group and five in the stent graft group. Two patients in the stent graft group had received a renal transplant. The number of interventions per patient-year was 1.9 in the bare stent group and 0.9 in the stent graft group (P = .02). CONCLUSIONS: The use of stent grafts in angioplasty for recurrent cephalic arch stenosis significantly improved short-term restenosis rates and long-term patency compared with the use of bare stents. The significant improvement that emerged during the study caused accrual of patients to be halted for ethical reasons. This study altered our usage of stents for venous stenoses in arteriovenous accesses by eliminating bare nitinol stents in favor of stent grafts.

Blood flow volume changes in the maturing arteriovenous access for hemodialysis.

In our center, we start hemodialysis using arteriovenous accesses empirically 1 mo after surgery in nearly all patients, when the vein diameter reaches 5 mm and blood flow is assumed to be adequate. We measured blood flow and vessel diameter in the maturing autogenous and prosthetic access to determine if this approach can be justified by quantitative physiological parameters. Of 66 consecutive autogenous and prosthetic arteriovenous accesses created over 3 mo in 2004, 62 were prospectively examined by duplex ultrasonography preoperatively, immediately after surgery in the recovery room, at 10 d postoperatively and 1 mo after surgery before first cannulation. In the 20 forearm accesses, the immediate postoperative mean blood flow was 549 +/- 189 mL/min, 885 +/- 227 mL/min at 10 d and 934 +/- 260 mL/min at 1 mo. In the 22 upper-arm accesses, the immediate postoperative mean access blood flow was 858 +/- 292 mL/min, 1060 +/- 326 mL/min at 10 d and 1116 +/- 427 mL/min at 1 mo. In 20 prosthetic accesses, near maximal flow was attained immediately after surgery (990 +/- 256 mL/min). Most of the increased flow in autogenous accesses occurred early in the maturation process. This suggests that 1 mo is adequate for autogenous access maturation before use for hemodialysis. The process of access maturation appears to be less relevant in prosthetic accesses, where blood flow is high from the day of surgery and tissue incorporation is, therefore, more important.

[Possible ramifications of prolonged standing at the workplace and its association with the development of chronic venous insufficiency].

The issue of working conditions and their health ramifications have recently been raised on the public agenda in Israel with special emphasis on occupations requiring prolonged standing. This review article discusses the physiological and medical aspects of prolonged standing in the workplace. Searching the literature, 19 studies were found which specifically examined the effect of prolonged standing versus prolonged sitting at work. Most of these studies suggested that prolonged standing may result in the development and aggravation of chronic venous insufficiency. The association between prolonged standing and venous insufficiency was found to be more pronounced in women than in men.

Stent grafts for treatment of cannulation zone stenosis and arteriovenous graft venous anastomosis.

Stent grafts (SGs) are widely used for treatment of failing vascular accesses, fistulas and grafts. The mechanical barrier of the covered stent prevents in-stent stenosis and can be used to effectively correct ruptured vein and aneurysms. Treatment of cannulation zone stenosis with SG can be justified when its use is obligatory, in order to prevent total access loss. Although there are worrying complications attendant on SG insertion and cannulation, including jeopardizing future access creation, most studies report no complications of SG in cannulation zone stenosis. SGs for treatment of arteriovenous graft venous anastomosis stenosis is controversial. Two large randomized trials conclusively demonstrate improved primary patency with SGs at the venous anastomosis of arteriovenous graft at up to two years when compared with percutaneous transluminal angioplasty, sustained for up to 2 years and reducing the number of interventions per patient year. However, the ultimate goal of SG treatment of venous anastomosis stenosis is preventing thrombosis and increasing graft longevity, which was unfortunately not fully achieved.

General, regional or local anesthesia for successful radial cephalic arteriovenous fistula.

Autogenous fistulas and in particular radiocephalic fistulas are recommended as the first vascular access for hemodialysis. Unfortunately, the rates of early failure and non-maturation are very high. For more than a decade, brachial plexus block has been proposed as the anesthesia of choice for fistula creation due to its beneficial sympathectomy-like effect, causing vasodilation and attenuation of spasm. Until recently, there was not a single randomized clinical study supporting this proposition. Because performing regional anesthesia is time-consuming and requires expertise, many surgeons prefer local or general anesthesia for vascular access surgery. However, in August 2016 a randomized clinical trial was published showing that regional anesthesia significantly reduces early failure and improves primary and functional patency at 3 months compared to local anesthesia. The aging of the dialysis population, with their attendant morbidity and increased risk for general anesthesia, makes it clear that regional anesthesia is the recommended approach for fistula creation. The excess time required for this approach will decrease with increasing expertise along the learning curve, and will be compensated by a reduction in time that would otherwise be needed for new access construction due to failure of fistulas constructed under local anesthesia.