High‐output heart failure secondary to arteriovenous fistula

In the hemodialysis patient population, a surgically created arteriovenous fistula is the preferred vascular access option. Development of high‐output heart failure may be an underappreciated complication in patients who have undergone this procedure. When a large proportion of arterial blood is shunted from the left‐sided circulation to the right‐sided circulation via the fistula, the increase in preload can lead to increased cardiac output. Over time, the demands of an increased workload may lead to cardiac hypertrophy and eventual heart failure. Patients may present with the usual signs of high‐output heart failure including tachycardia, elevated pulse pressure, hyperkinetic precordium, and jugular venous distension. Typically, the AV fistula is quite large and is likely located in the upper arm, more proximal to the heart. Routine access flow monitoring should demonstrate blood flows (Qa) >2000 ML/min. Echocardiogram may reveal either a low or high left ventricular ejection fraction, and right‐heart catheterization demonstrates an elevated cardiac output with a low to normal systemic vascular resistance. When addressing the problem of high‐output heart failure, the nephrologist is faced with the dilemma of preventing progression of heart failure at the expense of loss of vascular access. Nevertheless, treatment should be directed at correcting the underlying problem by surgical banding or ligation of the fistula.     

Vascular access for chronic hemodialysis in a patient with epidermolysis bullosa dystrophica Hallopeau‐Siemens

Epidermolysis bullosa is a rare genetic hereditary disease characterized with mechanobullous dermatosis. Except cutaneous, these patients have various extracutaneous manifestations and some types of epidermolysis bullosa comprise almost all organ systems. Because of prolonged life span, chronic renal insufficiency has become an important cause of morbidity and death in these patients. Establishment of functional vascular dialysis access is a great challenge for both the doctors and the patients. Multidisciplinary approach is essential. We present a case of successful establishment of dialysis access via Tesio catheter in a young woman suffering from epidermolysis bullosa dystrophica Hallopeau‐Siemens and end‐stage renal disease. Since then, the Tesio catheter inserted via the right internal jugular vein has been the functional mean of dialysis. The patient was given the opportunity to lead a quality and active life in spite of disabling disease. Several cases of successful dialysis access establishment with dialysis catheters via central veins have been reported. We report the successful establishment of long‐term dialysis access via Tesio catheter and suggest this approach as ideal for these patients. This is the first report dealing with vascular access in this group of patients.     

Surgical Revision and Early Cannulation of the Arteriovenous Fistula in Hemodialysis Patients: An Effective Technique

Arteriovenous fistula (AVF) dysfunction is a common problem in hemodialysis patients. After surgical revision for malfunction, we used AVFs early to avoid complications associated with central venous catheters. In this study, we report experience with surgical revisions of native AVFs with suspected arterial dysfunction as the cause of inadequate arterial inflow for dialysis. Exclusion criteria were presence of a central venous catheter as a hemodialysis access, and clinical or radiologic evidence of stenosis or thrombosis of the distal venous segment of the AVF. We prospectively studied 50 patients (mean age 60.2 ± 10.5 years, 25 men and 25 women) with 59 revisions. The patients were followed until change in the modality of dialysis, transplant, or death. The types of AVFs revised were left wrist radiocephalic in 27 patients (54%), left forearm radiocephalic in 10 (20%), right wrist radiocephalic in 6 (12%), left antecubital brachiocephalic in 3 (6%), right antecubital brachiocephalic in 2 (4%), and right forearm radiocephalic in 2 (4%). The causes of inadequate arterial flow were juxta‐anastomotic thrombosis in 20 patients (40%), inadequate arterial anastomotic flow in 16 (32%), inadequate anastomosis in 7 (14%), and juxta‐anastomotic venous stenosis in 7 (14%). The primary surgical revision techniques were proximal neo‐anastomosis using the semiarterialized vein in 43 patients (86%), thrombectomy and re‐anastomosis in 5 (10%), and resection and repair in 2 (4%). Technical success, defined as successful cannulation of the revised AVF for hemodialysis and avoidance of central venous catheter, was achieved in 44 of 50 patients (88%). Technical failure occurred 6 cases, the causes being inadequate arterial flow in 3 patients, failure to cannulate the veins in 2 patients, and steal syndrome in 1 patient. After primary revisions failed, 9 re‐revisions were done in 6 patients. The 1‐year, 2‐year, and 3‐year primary and overall patency rates were 76.2%, 67.6%, 65.0%, and 85.7%, 75.7%, 65.0%, respectively. In conclusion, surgical salvage of the AVF with inadequate arterial flow is an effective approach that can be performed as an outpatient procedure and allows early cannulation of the semi‐arterialized veins, thus avoiding the use of central venous catheters.     

Maintenance of blood flow rate on dialysis with self‐centering CentrosFLO catheter: A multicenter prospective study

Introduction Chronic central venous catheters (CVC) for dialysis lose patency and deliver lower blood flow over time, often due to fibrous sheathing that covers the lumen tips. The CentrosFLO central venous catheter has a shape that directs the arterial and venous tips away from the walls of the vena cava and right atrium, making sheathing of the tips less likely. Methods A prospective, multicenter, single arm, non‐controlled, observational study was conducted at eight sites in the United States. All consenting dialysis patients receiving CentrosFLO catheters through the right or left internal jugular veins were accepted in the study, as long as the catheter was expected to be used for 45 days and was not an over‐the‐wire replacement for a previous CVC. Data were automatically collected on initial and average dialysis blood flow rate and initial arterial and venous pressures, for up to 26 weeks of dialysis therapy. Findings 75 patients were enrolled. Kaplan‐Meier analysis indicated that 87% of patients maintained blood flow rate over 300 mL/min throughout 26 weeks of follow‐up. There was no decline in average dialysis blood flow rate and no significant change in hydraulic resistance of the arterial or venous lumens of the catheters during the study. Discussion The CentrosFLO catheter demonstrates long term patency with good flow rates on dialysis, which, by comparison with previous studies, shows a clinically significant improvement in blood flow rate vs. other catheters. Stable hydraulic resistance of the catheter lumens showed no evidence of tip encroachment by fibrous sheaths.     

Dynamic Probability Control Limits for Lower and Two‐Sided Risk‐Adjusted Bernoulli CUSUM Charts

Because of its advantages of design, performance, and effectiveness in reducing the effect of patients' prior risks, the risk‐adjusted Bernoulli cumulative sum (CUSUM) chart is widely applied to monitor clinical and surgical outcome performance. In practice, it is beneficial to obtain evidence of improved surgical performance using the lower risk‐adjusted Bernoulli CUSUM charts. However, it had been shown that the in‐control performance of the charts with constant control limits varies considerably for different patient populations. In our study, we apply the dynamic probability control limits (DPCLs) developed for the upper risk‐adjusted Bernoulli CUSUM charts to the lower and two‐sided charts and examine their in‐control performance. The simulation results demonstrate that the in‐control performance of the lower risk‐adjusted Bernoulli CUSUM charts with DPCLs can be controlled for different patient populations, because these limits are determined for each specific sequence of patients. In addition, practitioners could also run upper and lower risk‐adjusted Bernoulli CUSUM charts with DPCLs side by side simultaneously and obtain desired in‐control performance for the two‐sided chart for any particular sequence of patients for a surgeon or hospital.     

Hemodialysis decreases carotid‐brachial and carotid‐femoral pulse wave velocities: A 5‐year follow‐up study

Aortic stiffness is a prognostic parameter associated with patient mortality. Vascular access creation has been shown to have effects on arterial stiffness both in the aorta and in the upper limb arteries in chronically hemodialyzed patients (CHPs). However, no longitudinal studies have been conducted in order to characterize the evolution of arterial stiffness in CHPs. The aims of this work were (a) to measure baseline pulse wave velocity (PWV) in the carotid‐femoral and in right and left carotid‐brachial pathways in a cohort of CHP and (b) to conduct a 5‐year prospective study on the same cohort to determine possible time‐related differences. Pulse wave velocity was measured both in the carotid‐femoral and in the carotid‐brachial pathways, and clinical and biochemical parameters were collected in 25 CHPs, which were followed up after a 5‐year lapse. Right and left carotid‐brachial pathway PWV values showed significant decreases after the 5‐year follow‐up, independently of the presence of the vascular access (P < 0.001). Additionally, baseline carotid‐brachial PWV was significantly higher (P < 0.001) than values measured 5 years later for upper limbs with vascular access (11.97 ± 2.97 m/sec vs. 6.76 ± 1.48 m/sec, respectively) and without vascular access (12.25 ± 2.38 m/sec vs. 7.18 ± 1.88 m/sec, respectively). Similarly, PWV values in the carotid‐femoral pathway decreased significantly (P < 0.001) over the same period (13.27 ± 2.96 m/sec vs. 9.75 ± 2.99 m/sec, respectively). The 5‐year follow‐up of PWV showed significant decreases in both carotid‐brachial and carotid‐femoral pathways. The general changes in arterial stiffness could be related to the vascular access creation, hemodialysis therapy, and to the improvement of arterial pressure management.     

Single‐lumen tunneled catheter: An old but useful option

We report a case of long‐term uneventful catheter use in a patient with previous recurrent vascular access dysfunction and infection. A single‐lumen tunneled catheter was inserted into the left internal jugular vein after a failed attempt of dual‐lumen permanent catheter placement. The follow‐up since device implantation has exceeded 5 years without any complications related to vascular access.     

Single‐ and Double‐Sided Chemical Functionalization of Bilayer Graphene

An experimental study on the interaction between the top and bottom layer of a chemically functionalized graphene bilayer by mild oxygen plasma is reported. Structural, chemical, and electrical properties are monitored using Raman spectroscopy, transport measurements, conductive atomic force microscopy and X‐ray photoelectron spectroscopy. Single‐ and double‐sided chemical functionalization are found to give very different results: single‐sided modified bilayers show relatively high mobility (200–600 cm² V^?1 s^?1 at room temperature) and a stable structure with a limited amount of defects, even after long plasma treatment (>60 s). This is attributed to preferential modification and limited coverage of the top layer during plasma exposure, while the bottom layer remains almost unperturbed. This could eventually lead to decoupling between top and bottom layers. Double‐sided chemical functionalization leads to a structure containing a high concentration of defects, very similar to graphene oxide. This opens the possibility to use plasma treatment not only for etching and patterning of graphene, but also to make heterostructures (through single‐sided modification of bilayers) for sensors and transistors and new graphene‐derivatives materials (through double‐sided modification).     

Infective spondylodiscitis in patients on high‐flux hemodialysis and on‐line hemodiafiltration

Infective spondylodiscitis (ISD) is a rare but potentially devastating condition in hemodialysis (HD) patients. Reports are limited especially in patients receiving high‐flux HD and hemodiafiltration (HDF). In a retrospective analysis, 13 patients on our maintenance high‐flux HD/HDF program were identified as having has infective spondylodiscitis over a 10‐year period (1997–2006), an incidence of approximately 1 episode every 215 patient‐years. The incidence was around 3 times higher in patients dialyzing with tunnelled central venous catheters (TCVC) than in those with arteriovenous fistulae. Affected patients were elderly (mean age 70 years) and had multiple comorbidities. Access problems, particularly TCVC infection, were common in the months preceding it's onset. Tunnelled central venous catheter removal during these episodes did not necessarily prevent it. Diagnosis was based on a history of back pain, raised C‐reactive protein, positive blood cultures, and characteristic magnetic resonance findings. Many patients were apyrexial and had normal white cell counts. In our patients on high‐flux HD/hemodiafiltration, its incidence appears comparable to that in conventional HD settings. No patients had infection with waterborne organisms. Blood cultures were positive in 77%. Gram‐positive organisms predominated, particularly Staphylococcus aureus. The major route of infection was hematogenous, with the most likely source the venous access. All received antibiotics for 6 to 12 weeks or until death. Only 2 patients underwent surgical drainage. Mortality was high (46%) and predicted by the development of complications, and by pre‐existing cardiovascular comorbidity. Prevention, using strategies to reduce the prevalence of bacteremia, including limiting the use of TCVC, should be an overriding aim.     

Late onset of clinically apparent central vein stenosis due to previous central venous catheter in a patient with inherited thrombophilia

We describe a case of a patient with a functional kidney transplant who was admitted to our department with clinically evident central vein stenosis (CVS) 7 years after the removal of a central venous catheter (CVC) from the right internal jugular vein. The catheter was used as a hemodialysis access for a 2‐month period. In the interval before his last admission, the patient suffered two episodes of deep vein thrombosis. Investigation revealed heterozygosity for factor V Leiden, the most common inherited thrombophilia encountered in 5% of Caucasians, and anticoagulation treatment was started. Magnetic resonance angiography showed stenosis just after the convergence of the right subclavian vein with the internal jugular vein to the innominate vein. Transluminal angioplasty restored venous patency and right upper arm edema resolved. Coexistence of CVS, accompanied by hemodynamic changes and endothelial dysfunction, with thrombophilia fulfill all the elements of the Virchow's triad. Therefore, the patient was at great risk for central vein thrombosis, from which he was possibly protected by the early administration of anticoagulant treatment. This case indicates that CVS can be asymptomatic for several years after CVC removal and also raises the question if thrombophilia workup and investigation for CVS may be beneficial in every patient with CVC placement in order to avoid any harmful outcomes.     

Nonparametric cost‐minimized Shewhart‐type process monitoring with restricted false alarm probability

Traditional Duncan‐type models for cost‐efficient process monitoring often inflate type I error probability. Nevertheless, controlling the probability of type I error or false alarms is one of the key issues in sequential monitoring of specific process characteristics. To this end, researchers often recommend economic‐statistical designs. Such designs assign an upper bound on type I error probability to avoid excessive false alarms while achieving cost optimality. In the context of process monitoring, there is a plethora of research on parametric approaches of controlling type I error probability along with the cost optimization. In the nonparametric setup, most of the existing works on process monitoring address one of the two issues but not both simultaneously. In this article, we present two distribution‐free cost‐efficient Shewhart‐type schemes for sequentially monitoring process location with restricted false alarm probability, based, respectively, on the sign and Wilcoxon rank‐sum statistics. We consider the one‐sided shift in location parameter in an unknown continuous univariate process. Nevertheless, one can easily extend our proposed schemes to monitor the two‐sided process shifts. We evaluate and compare the actual performance of the two monitoring schemes employing extensive computer simulation based on Monte Carlo. We investigate the effects of the size of the reference sample and the false alarm constraint. Finally, we provide two illustrative examples, each based on a realistic situation in the industry.     

Dialysis access venous stenosis: Treatment with balloon angioplasty 30‐second vs. 1‐minute inflation times

Percutaneous balloon angioplasty is the standard of care in the endovascular treatment of dialysis access venous stenosis. The significance of balloon inflation times in the treatment of these stenoses is not well defined. Our objective was to examine the outcomes of 30‐second vs. 1‐minute balloon inflation times on primary‐assisted patency of arteriovenous fistulae and grafts. Using a prospectively collected vascular access database, we identified a total of 75 patients referred for access dysfunction during a 5‐year period. These patients received 223 interventions (178 with 30‐second inflations and 45 with 1‐minute inflations). We compared primary‐assisted patency during the subsequent 9 months across groups defined by inflation times. Demographics and baseline characteristics were similar across groups. Immediate technical success and patency in the first 3 months were similar across groups (hazard ratio [HR] = 0.86; 95% confidence interval [CI]: 0.34–2.20). After 3 months, however, a 1‐minute inflation time was associated with greater incidence of access failure (adjusted HR [aHR] = 1.74; 95% CI: 1.09–2.79). Other predictors of access failure included age over 60 (aHR = 1.02; 95% CI: 1.01–1.04), central location of the lesion (aHR = 2.49; CI: 1.27–4.89), and three or more prior procedures (aHR 2.48; CI: 1.19–5.16). Our data suggest that shorter balloon inflation times may be associated with improved longer term access patency, although the benefit was not observed until after 3 months. Given the increasing demands of maintaining access patency in the era of the National Kidney Foundation Kidney Disease Outcomes Quality Initiative and Fistula First, the role of angioplasty times requires further study.     

Multivariate Process Capability Vector Based on One‐Sided Model

To evaluate the capability of manufacturing processes in satisfying the customer's needs, a variety of indices has been developed. Some of them are introduced by researchers to analyse the processes with multivariate quality characteristics. Most of the proposed in the literature multivariate capability indices are defined under assumption of normality distribution of the quality characteristics. Thus, the process region describing the variation of the data has an elliptical shape. In this paper, a multivariate process capability vector with three components is introduced, which allows to access the capability of a process with both normally and non‐normally quality characteristics due to application of a pair of one‐sided models as the process region shape. At the beginning, one‐sided models are defined, next the proposed vector components are proposed and the methodology of their evaluation is presented. The methodology (which in fact could be also applied to both the correlated and non‐correlated characteristics) is verified by applying simulation and real problems. The obtained results show that the proposed methodology performs satisfactorily in all considered cases. Copyright © 2014 John Wiley & Sons, Ltd.     

Remove or not,that is the question: A case report on carotid artery cannulation during indwelling venous hemodialysis catheter

A 58‐year‐old woman visited the emergency department for acute occlusion of arteriovenous fistula. One session of hemodialysis was scheduled via temporary venous hemodialysis catheter before thrombectomy. Unfortunately, neck arterial cannulation was discovered after complete placement of catheter. The catheter was removed immediately but bleeding could not be stopped. Pseudoaneurysm over the right carotid artery was proved by angiography and repaired by graft stent. Arterial cannulation during venous hemodialysis catheter insertion is a rare but serious complication and there is no standard response recommended. Immediate removal of the misplaced hemodialysis catheter might not be the best choice. We suggest to leave the misplaced catheter in artery until further intervention in consideration of complications and repair access. Every hemodialysis center should standardize responses to arterial cannulation during venous hemodialysis catheter indwelling, especially carotid puncture happens, according to the medical facility.     

Our experience in using the brachial venae comitantes as a native vascular access for hemodialysis

A native arteriovenous fistula is the preferred vascular access for patients on long‐term hemodialysis. In the absence of suitable superficial veins, the deep venous system can be used. We intend to present our experience in using the brachial venae comitantes (VC) to create a native arteriovenous fistula. From January 2012 to December 2014, we utilized the brachial vena comitantes to create 12 arteriovenous fistulae. Data from these 12 subjects were analyzed retrospectively to produce this case series. The average age of our subjects was 55.6 years. Forty‐two percent of the subjects were women. Fifty percent of the subjects had diabetes mellitus and 58% had hypertension. We achieved a functional patency rate of 58% at 1 month's follow up after maturation. The brachio–brachial vena comitans fistula is a safe and plausible option in patients with no other suitable veins for a native fistula, more so in the hands of experienced surgeons. The longer time to cannulation has to be taken into consideration when creating a VC fistula. In suitable patients with end‐stage renal disease, it can delay the use of an arteriovenous graft or a tunneled central venous catheter.     

Hemothorax caused by replacement of hemodialysis catheter: A case report

Central venous catheters (CVC) are widely used in clinics to gain vascular access, but the risk and prevalence of catheter‐related complications remains a serious issue. We report a long‐term dialysis catheter accidentally inserted into the mediastinum via the right jugular vein in a hemodialysis patient. We also review complications associated with vascular catheterization and propose immediate therapeutic interventions for such cases.     

Late‐onset Pompe's disease in a hemodialysis patient: A first case report

A 37‐year‐old hemodialysis patient appeared with unusual somnolence during 2 successive hemodialysis sessions. Blood gas analysis revealed hypercapnic respiratory failure and spirometry restrictive lung disease. After exclusion of other causes of restrictive lung disease with chest CT‐scan and cerebrum MRI, electrophysiological study revealed myopathy. Because besides lordosis and limb‐girdle gait the patient was ambulant the possibility of late‐onset Pompe's disease was set and confirmed with evaluation of α‐glucosidase activity and genetic analysis. Enzyme replacement therapy (ERT) with aglucosidase alfa was started. Due to inaccessibility of veins in the arm without the arteriovenous fistula, during the last 1 year, the patient received the ERT through the venous line of the hemodialysis circuit. Three years later the patient remains ambulant without the need of any assistant device and preserved his pulmonary function. This is the first described case of late‐onset Pompe's disease in a hemodialysis patient treated with ERT.     

Beidseitige Innen‐ und Außenbeschichtung von PET‐Getränkeflaschen

Double‐sided interior and exterior coating of PET beverage bottles Plasma‐enhanced methods for the interior coating of PET beverage bottles have already been put into practice in the industry. Thereby the achieved barrier properties are limited due to defects in the coating, which emerge during the layer growth and allow a higher permeability. One possible way to improve barrier properties is the double‐sided coating. The implementation of the concept in form of a demonstrator plant is presented. By means of optical emission spectroscopy (OES) as a very versatile and easy to use method for the surveillance of industrial plasma processes, the influence of the gas composition on the plasma homogeneity and barrier properties of the coating is demonstrated. Permeation measurements are carried out, showing the potential of the combined coating process for the deposition of effective coatings.     

Brachial‐cephalic fistula recovered with drainage for the basilic vein: Case report

Vascular access is essential for the implementation of hemodialysis (HD). The arteriovenous fistula (AVF) can be constructed in various locations using various veins. However, the quality of the veins will influence the construction site, as well as the functioning of the AVF. Careful analysis of the vascular network allows options for the development of new fistulas presentations. We present and discuss the case of a woman aged 69 years in HD in which a brachial‐cephalic fistula with drainage to basilic vein was created, through rotation of the cephalic vein on the forearm level. This kind of access serves to prolong the time spent dialyzing through native fistulae, with their reduced complications and greater cost‐effectiveness.     

Hybrid Flexible Resistive Random Access Memory‐Gated Transistor for Novel Nonvolatile Data Storage

Here, a single‐device demonstration of novel hybrid architecture is reported to achieve programmable transistor nodes which have analogies to flash memory by incorporating a resistive switching random access memory (RRAM) device as a resistive switch gate for field effect transistor (FET) on a flexible substrate. A high performance flexible RRAM with a three‐layered structure is fabricated by utilizing solution‐processed MoS₂ nanosheets sandwiched between poly(methyl methacrylate) polymer layers. Gate coupling with the pentacene‐based transistor can be controlled by the RRAM memory state to produce a nonprogrammed state (inactive) and a programmed state (active) with a well‐defined memory window. Compared to the reference flash memory device based on the MoS₂ floating gate, the hybrid device presents robust access speed and retention ability. Furthermore, the hybrid RRAM‐gated FET is used to build an integrated logic circuit and a wide logic window in inverter logic is achieved. The controllable, well‐defined memory window, long retention time, and fast access speed of this novel hybrid device may open up new possibilities of realizing fully functional nonvolatile memory for high‐performance flexible electronics.