Recovery from kidney failure associated with chronic thromboembolic pulmonary hypertension following pulmonary thomboendarterectomy.

The occurrence of renal failure in pulmonary hypertension (PH) is an ominous sign and implies excessive adverse hemodynamic factors. Pharmacologic agents to treat the PH are the mainstay of management, whereas diuretics assist in management of fluid overload. However, when such measures fail, dialysis and ultrafiltration (UF) become necessary to manage progressive azotemia and hypervolemia. Reversal of PH is essential to interrupt this vicious cycle of multisystem failure; otherwise, the need for renal replacement therapy would be permanent.

De Novo Fibrinogen A Alpha Chain Amyloidosis in a Kidney Transplant Patient: Case Report and Literature Review.

Rationale: De Novo transplant amyloidosis denotes the condition when a patient develops amyloidosis after transplantation but had not been diagnosed with the disease prior to transplantation. The incidence of de novo amyloidosis in kidney transplants is rare, but few published case reports have described the occurrence of de novo Amyloid A protein (AA) and Light Chain (AL) amyloidosis. However, de novo hereditary fibrinogen A alpha chain (AFib) has not been previously reported. Patient Presentation: We present a 72-year-old man, a kidney transplant recipient, who developed progressive rise in his creatinine about 3 years after transplantation. He has long-standing diabetes mellitus type 2, obesity, and hypertension, so he did not have a kidney biopsy of his native kidneys prior to transplantation. Diagnosis: A kidney transplant biopsy was done that showed amyloidosis. Mass spectrophotometry confirmed it as AFib amyloidosis. Genetic testing of the patient revealed that he has fibrinogen A alpha gene (FGA) point mutation with a p.E545V variant. Interventions: Cardiac evaluation showed normal transthoracic echocardiogram. Cardiac magnetic resonance imaging (MRI) showed no involvement by amyloidosis. A peripheral nerve biopsy showed diabetic neuropathy. Thus, the kidney was the only organ involved by the disease. The kidney transplant was managed conservatively with blood pressure and diabetes control in addition to his usual immunosuppression regimen which was not altered. He is being treated with diuretics, angiotensin receptor inhibitors, and sodium glucose transport 2 inhibitors. Outcomes: Kidney transplant function exhibited only slow progression over 18 months since the diagnosis was confirmed. This slow progression is likely because the p.E545V point mutation variant is less aggressive than other gene deletion mutations and because our patient was judged to have been diagnosed early in the course of his disease. Teaching Points: In this case report, we illustrate the findings and testing that confirmed the diagnosis of AFib amyloidosis. We summarize the clinical aspects, outcomes of the disease, and treatment options. We believe this case report is interesting because it is the first reported case of AFib amyloidosis in a kidney transplant recipient who was not known to have the disease prior to kidney transplantation.

Justification: L'amyloïdose de novo de la transplantation désigne l'état d'un patient qui développe une amylose après une transplantation alors que la maladie n'avait pas été diagnostiquée avant l'intervention. L'incidence de l'amyloïdose de novo est rare en contexte de transplantation rénale, bien que la survenue d'amyloses AA et al de novo ait été décrite dans quelques rapports de cas publiés. L'amyloïdose de novo héréditaire de la chaîne alpha du fibrinogène A (FibA) n'a cependant jamais été rapportée. Présentation du patient: Nous présentons le cas d'un homme de 72 ans, receveur d'une greffe rénale, dont le taux de créatinine a augmenté progressivement environ trois ans après la transplantation. Le patient souffrait depuis longtemps de diabète de type 2, d'obésité et d'hypertension, de sorte qu'il n'avait pas subi de biopsie de ses reins d'origine avant la transplantation. Diagnostic: Une biopsie du greffon rénal a montré une amyloïdose, laquelle a ultérieurement été typée par spectrophotométrie de masse comme étant une amyloïdose FibA. Des tests génétiques ont révélé que le patient présentait une mutation ponctuelle du gène alpha du fibrinogène (FGA) avec le variant p.E545V. Interventions: L'échocardiogramme transthoracique du bilan cardiaque était normal. L'IRM cardiaque n'a montré aucune implication par amyloïdose, et une biopsie des nerfs périphériques a révélé une neuropathie diabétique. Ainsi, le rein était le seul organe touché par la maladie. La greffe rénale a été gérée de manière conservatrice, soit par le contrôle de la pression artérielle et du diabète en plus du schéma habituel d'immunosuppression, lequel n'a pas été modifié. Le patient est traité avec des diurétiques, des inhibiteurs des récepteurs de l'angiotensine et des inhibiteurs du cotransport sodium-glucose de type 2. Résultats: La fonction du greffon n'a montré qu'une lente progression sur 18 mois depuis la confirmation du diagnostic. Cette lente progression est probablement due au fait que la mutation ponctuelle p.E545V est moins agressive que d'autres mutations de délétion du gène, et parce que notre patient a été jugé comme ayant reçu son diagnostic tôt dans l'évolution de sa maladie. Enseignements tirés: Dans ce rapport de cas, nous mettons en évidence les résultats et tests qui ont confirmé le diagnostic d'amyloïdose FibA. Nous résumons les aspects cliniques, le pronostic de la maladie et les options de traitement. Ce rapport de cas est intéressant, car il s'agit du premier cas rapporté d'amyloïdose FibA chez un receveur d'une greffe rénale sans diagnostic connu de la maladie avant la transplantation.

ASDIN white paper: Management of cephalic arch stenosis endorsed by the American Society of Diagnostic and Interventional Nephrology.

Brachiocephalic arteriovenous fistulas (AVF) makeup approximately one third of prevalent dialysis vascular accesses. The most common cause of malfunction with this access is cephalic arch stenosis (CAS). The accepted requirement for treatment of a venous stenosis lesion is ⩾50% stenosis associated with hemodynamically abnormalities. However, the correlation between percentage stenosis and a clinically significant decrease in access blood flow (Qa) is low. The critical parameter is the absolute minimal luminal diameter (MLD) of the lesion. This is the parameter that exerts the key restrictive effect on Qa and results in hemodynamic and functional implications for the access. CAS is the result of low wall shear stress (WSS) resulting from the effects of increased blood flow and the unique anatomical configuration of the CAS. Decrease in WSS has a linear relationship to increased blood flow velocity and neointimal hyperplasia exhibits an inverse relationship with WSS. The result is a stenotic lesion. The presence of downstream venous stenosis causes an inflow-outflow mismatch resulting in increased pressure within the access. Qa in this situation may be decreased, increased, or within a normal range. Over time, the increased intraluminal pressure can result in marked aneurysmal changes within the AVF, difficulties with cannulation and the dialysis treatment, and ultimately, increasing risk of access thrombosis. Complete characterization of the lesion both hemodynamically and anatomically should be the first step in developing a strategy for management. This requires both access flow measurement and angiographic imaging. Patients with CAS present a relatively broad spectrum as relates to both of these parameters. These data should be used to determine whether primary treatment of CAS should be directed toward the anatomical lesion (small MLD and low Qa) or the pathophysiology (large MLD and high Qa).

Atypical Posterior Nutcracker Syndrome in a 17-Year-Old Male Without Hematuria.

Retro-aortic left renal vein (RLRV) is an anatomical variation, where the left renal vein (LRV) courses posterior to the aorta and anterior to the vertebrae before it eventually drains into the inferior vena cava (IVC). RLRV is a rare finding, with a prevalence of around 1%-2%, and only a small minority of RLRVs cause symptoms. RLRV symptoms occur secondary to compression of the LRV between the abdominal aorta and vertebrae, otherwise known as posterior nutcracker syndrome (PNCS). The most common symptoms of PNCS are hematuria and flank pain. We present a 17-year-old male, who came in with recurring left flank pain without hematuria, initially thought to be renal colic secondary to nephrolithiasis. On further investigations, an aberrant posterior renal vein was seen on CT suggestive of PNCS. The patient was treated successfully with RLRV vascular stent placement by interventional radiology. This case report adds to the limited number of PNCS cases observed in children and to the even rarer cases of PNCS without hematuria. This case also acts as a reminder for pediatricians to keep a wide scope of differentials in patients presenting with flank pain and provides an outline of both diagnostic and treatment modalities available for these patients.

Discovery of a large axillary artery vascular malformation during the evaluation of a patient with hemodialysis access-induced distal ischemia: Implications on pathophysiology and management.

A patient with a 6-year-old left upper arm brachial cephalic AVF presented with symptoms of hemodialysis access-induced distal ischemia (HAIDI). Physical exam findings showed a well-developed AVF, but compression of the AVF aggravated arm pain and induced diffuse erythema of the left upper extremity. Angiographic evaluation disclosed the presence of a large axillary artery vascular malformation (AVM) as well as distal forearm hypo-perfusion. We elected to publish this case report to describe the interesting physical exam findings related to the AVM, and discuss HAIDI treatment options that are peculiar to this case. We also highlight the importance of thorough vascular evaluation prior to AV access creation as well as during the investigation of the cause of HAIDI.

The effect of angioplasty of single arteriovenous fistula-associated stenosis on arteriovenous fistula blood flow rate.

INTRODUCTION: Percutaneous balloon angioplasty of arteriovenous fistula-associated stenosis is performed for a variety of indications. Successful percutaneous transluminal angioplasty (PTA) is expected to increase in arteriovenous fistula blood flow rate (Qa). A validated approach to predicting changes in Qa based upon stenosis characteristics is not available. METHODS: Three baseline parameters were determined in a group of patients with a single arteriovenous fistula-associated stenosis undergoing PTA. These were percent estimated stenosis, stenosis minimum luminal diameter, and baseline Qa. The relationship between these parameters and changes in Qa following PTA was analyzed using Spearman's rank correlation and linear regression. RESULTS: 113 patients (total group) were studied. Of these,106 had peripheral stenosis (total peripheral subgroup) and 7 had central stenosis. For the total group and total peripheral subgroup, a highly significant inverse correlation was seen between changes in Qa and baseline Qa. A weaker correlation was seen between changes in Qa and minimum luminal diameter, but no correlation was seen with percent estimated stenosis. A minimum luminal diameter ⩽2.0 mm was predictive of ⩾300-mL/min increases in Qa, whereas a minimum luminal diameter >4.5 mm was associated with <300-mL/min increases in Qa. PTA of Central vein stenosis was not associated with significant changes in Qa. CONCLUSION: Baseline Qa is the best predictor for change in Qa following PTA. Stenosis minimum luminal diameter cutoffs of ⩽2.0 and >4.5 mm are useful in predicting the magnitude of changes in Qa. Percent estimated stenosis is not predictive of change in Qa. PTA of central veins does not seem to change Qa.

ASDIN white paper: Assessment and management of hemodialysis access-induced distal ischemia by interventional nephrologists.

Although not common, hemodialysis access-induced distal ischemia is a serious condition resulting in significant hemodialysis patient morbidity. Patients with signs and symptoms suggestive of hand ischemia frequently present to the general and interventional nephrologist for evaluation. In order to care for these cases, it is necessary to understand this syndrome and its management. Most cases can be managed conservatively without intervention. Some cases requiring intervention may be treated using techniques within the scope of practice of the interventional nephrologists while other cases require vascular surgery. In order for the interventional nephrologists to evaluate and manage these cases in a timely and appropriate manner, practice guidelines are presented.

Exploring correlations between anatomic characteristics of dialysis arteriovenous fistula stenosis and arteriovenous fistula blood flow rate (Qa).

BACKGROUND: Radiologic justification for endovascular treatment of a dialysis arteriovenous fistula circuit stenosis is currently based on ⩾50% severity. However, the clinical significance of any given stenosis is not always clear. The minimum luminal diameter of any stenotic lesion in the arteriovenous fistula circuit might exert a more predictive effect on the arteriovenous fistula blood flow rate (Qa). METHODS: To investigate relationships between anatomic parameters of stenosis and Qa, this study was conducted in a cohort of patients with a variety of arteriovenous fistula stenotic lesions. The goals were to determine (1) the degree of correlation between arteriovenous fistula stenosis estimated during the procedure, and that which is measured, and (2) the correlations between two anatomic stenosis parameters (percent stenosis and stenosis minimum luminal diameter) and Qa. RESULTS: The cohort comprised 113 patients. Only a moderate correlation between estimated and measured stenosis was seen. A correlation between measured stenosis and Qa for the whole cohort was not seen, but a weak correlation between estimated stenosis and Qa was seen. Correlations between stenosis minimum luminal diameter and Qa were superior. The superiority of stenosis minimum luminal diameter to percent stenosis in correlating with a Qa of <500 mL/h was also demonstrated by receiver operating characteristics curve analysis. Stenosis minimum luminal diameter cutoffs of ⩽2.5 mm or >4 mm seemed to have a good predictive value of Qa. CONCLUSIONS: Percent stenosis determination is fraught with uncertainty and exhibits a weak correlation with Qa. Compared with percent stenosis, the minimum luminal diameter of the stenosis demonstrates a superior correlation with Qa.

Extrahepatic Malignancies After Treatment with Direct Antiviral Agents for Chronic HCV Infection.

BACKGROUND: Direct antiviral agents (DAAs) have become the treatment of choice for chronic hepatitis C virus (HCV). A safety concern was raised about a possible relationship between DDAs and malignancies. We report unexpected development of extrahepatic malignancies after DAA treatment. METHODS: Four hundred thirty-one patients were treated with DAAs in our unit between January 2015 and February 2018. The most common regimen used the combination of paritaprevir/ritonavir/ombitasvir with/without dasabuvir (PrOD) (141 patients, 32.7%). The most common genotype was G1b (317 patients, 73.5%). RESULTS: Nine patients (2.08%) were diagnosed with malignancies after treatment: three patients developed lymphoma, one laryngeal carcinoma, one pancreatic adenocarcinoma, one cervix carcinoma, one lung carcinoma, one developed recurrent transitional cell carcinoma of the urinary bladder, and one developed recurrent metastatic breast cancer. The incidence of these malignancies in the cohort was 696 to 100,000 for lymphoma and 232 to 100,000 for each one of the other malignancies described, while the incidence in the general population is 20, 8.8, 1.7, 44.7, 142, and 89.7 to 100,000, respectively. Five of these patients were treated with PrOD, two with sofosbuvir and daclatasvir, one with simeprevir and sofosbuvir, and one with ledipasvir and sofosbuvir. The occurrence of the malignancies was 3 months to 4 years after the end of the treatment. Besides, 10 patients (2.3%) developed HCC and one developed recurrent aggressive HCC. CONCLUSIONS: This report raises a question about a possible relationship between treatment with DAAs and development of extrahepatic malignancies. Thus, data collection from larger cohorts is critical to determine the relationship possibility.

Long-term Safety of Epoetin Alfa-epbx for the Treatment of Anemia in ESKD: Pooled Analyses of Randomized and Open-label Studies.

RATIONALE & OBJECTIVE: Epoetin alfa-epbx is a biosimilar to the reference product, epoetin alfa. We compare the safety of epoetin alfa-epbx versus epoetin alfa based on a pooled analysis of findings from 2 randomized, double-blind, comparative clinical studies, and report new data for the long-term safety of epoetin alfa-epbx. STUDY DESIGN: Pooled analyses of previously conducted studies. SETTING & PARTICIPANTS: Hemodialysis patients with anemia. INTERVENTIONS: Data from patients who received 1 or more subcutaneous or intravenous doses of study drug were integrated across route of administration in combined randomized groups (epoetin alfa-epbx, n = 423; epoetin alfa, n = 426). Data from patients who received 1 or more doses of epoetin alfa-epbx in either open-label extension trial were integrated across route of administration in a combined long-term safety studies group (n = 576). OUTCOMES: Adverse events (AEs), immunogenicity, and other outcomes were assessed. RESULTS: Incidences of treatment-emergent AEs, serious AEs, and discontinuation of study drug treatment because of treatment-emergent AEs were similar between combined randomized epoetin alfa-epbx and epoetin alfa, which had mean treatment durations of 18.1 and 17.7 weeks, respectively. Incidences of treatment-emergent AEs, serious AEs, and discontinuation of study drug treatment because of treatment-emergent AEs were 86.5%, 39.4%, and 6.6%, respectively, for the combined long-term safety studies group, which had a mean treatment duration of 40.0 weeks. In total, 12 patients across the combined randomized groups (epoetin alfa-epbx, n = 5; epoetin alfa, n = 7) and 9 patients in the combined long-term safety studies group tested anti-recombinant human erythropoietin antibody positive in 1 or more visits during study conduct. No patient in any group developed neutralizing antibodies or pure red blood cell aplasia. LIMITATIONS: Epoetin alfa comparator not included in the long-term safety studies, greater cumulative exposure to study drug for epoetin alfa-epbx, shorter follow-up in the randomized studies, and potential for selection bias among patients in the open-label long-term safety studies. CONCLUSIONS: This analysis reinforces previous conclusions of similar safety profiles between epoetin alfa-epbx and epoetin alfa. Furthermore, epoetin alfa-epbx had no unexpected safety signals during long-term treatment. FUNDING: This study was funded by Hospira Inc, which was acquired by Pfizer Inc in September 2015. TRIAL REGISTRATION: ClinicalTrials.gov EPOE-10-13 (NCT01473420); EPOE-10-01 (NCT01473407); EPOE-11-04 (NCT01628120); EPOE-11-03 (NCT01628107).

Management of transposed arteriovenous fistula swing point stenosis at the basilic vein angle of transposition by stent grafts.

INTRODUCTION: Transposed basilic vein arteriovenous fistulas suffer from stenosis at their basilic angle of transposition (BAT). This lesion exhibits frequent recurrence after angioplasty. The primary goal of this study was to determine the effect of stent-graft placement on BAT lesion- and access-patency. The secondary goals were to determine the frequency of intervention pre- and post-stent placement and stent-associated stenosis. METHODS: Thirty-seven cases had stent-grafts placed at their BAT to manage stenosis. Cases served as their own controls by analyzing their lesion- and access-patency pre- and post-stent placement. Student's t-test was used for analysis of continuous variables. Categorical variables were evaluated by Fisher's exact test. Tests were considered significant when p was ≤0.05. RESULTS: At 6 and 12 months, pre-stent lesion primary patency rates were 29% and 3%, and post-stent were 57% and 40%, respectively. Lesion primary assisted patency rates were 39% and 13%, and post-stent were 91% and 80%, respectively. At 6 and 12 months, pre-stent access primary patency rates were 29% and 3%, and post-stent were 26% and 19%, respectively. Pre-stent primary access assisted patency rates were 36% and 10%, and post-stent were 82% and 75%, respectively. Lesion intervention rates averaged 0.47/month pre-stent and 0.13/month post-stent. Access intervention rate averaged 0.50/month pre-stent, and 0.15/month post-stent. Stent-associated stenosis was seen in 23 cases. CONCLUSIONS: Treatment of BAT stenosis with stent-grafts had positive impact on the target lesion and the dialysis access circuit.

Open repair and venous inflow plication of the arteriovenous fistula is effective in treating vascular steal syndrome.

BACKGROUND: Vascular steal syndrome related to a dialysis arteriovenous fistula (AVF) can lead to symptoms of distal ischemia, limb loss, digit ulceration, and gangrene. Several complex procedures have been used to augment and restore distal limb perfusion while maintaining a functional AVF. We reviewed our experience in treating AVF-related vascular steal syndrome by simple plication of the initial AVF inflow segment. METHODS: Clinical data of 26 patients (15 men; mean age, 58 years; range, 26-80) with vascular steal syndrome related to their AVF underwent plication during a 36-month period. There were 18 brachial-cephalic AVFs and 8 brachial-basilic AVFs with vein transposition. Relevant clinical variables, imaging studies, and treatment variables were analyzed. RESULTS: Eighty-four percent of patients had hypertension, 62% were diabetics, and 15% had a previous limb or digit amputated. Hand pain, skin ulceration, or gangrene was present in 96%, 15%, and 12% of patients, respectively; 19% of patients had more than one symptom. Twelve (46%) patients had an aortic arch and upper extremity arteriogram, of which 67% showed evidence of arterial disease. One patient required percutaneous balloon-expandable stent treatment of a proximal left subclavian artery stenosis to improve flow. Duplex-derived volume flow measurements of the AVF were obtained with an average flow of 1.95 ± 0.83 L/min. Open repair and venous inflow plication was performed in all 26 patients. Average flow reduction in patients with preoperative and postoperative flow measurements was 0.6 ± 0.5 L/min (P < 0.05). There was a 12% revision rate within 3 months. Symptom resolution was achieved in 92% of patients while maintaining a functioning access out to 1 year. Two remaining patients who did not improve and proceeded to ligation of the AVF. CONCLUSIONS: Surgical plication of the initial AVF inflow segment offers a simple solution to preserve the dialysis access and resolve symptoms related to vascular steal associated with high volume flow through the AVF.

Percutaneous thrombectomy of AVF: immediate success and long-term patency rates.

The purpose of this study was to report the results obtained in a cohort of 520 cases of thrombosed arteriovenous fistulas (AVF) treated by percutaneous intervention over a period of 8 years. The methods used varied according to the individual characteristics of the case. A clinical success rate of 91.1% was obtained with no significant difference being noted among radial-cephalic, brachial-cephalic, and brachial-basilic AVFs. The mean primary patency for this group was 227.3 ± 14.6 days, and the mean assisted primary patency was 677.2 ± 44.6 days. The lower arm AVFs had both a primary patency and an assisted primary patency that were significantly better than the upper arm cases (p = 0.006 and 0.002, respectively). The primary patency for radial-cephalic AVFs was significantly better than that for brachial-cephalic AVFs (p = 0.021), but not for brachial-basilic cases (p = 0.122). Assisted primary patency for radial-cephalic cases was significantly superior to the values for either patients with a brachial cephalic (p = 0.046) or a brachial-basilic (p = 0.004). Complications occurred in seven cases (1.3%), all of which were venous ruptures. Blood flow was affected in four cases. Only one of these was salvaged with angioplasty balloon tamponade. In the remaining three cases, the AVF was lost.

Outcomes of cephalic arch stenosis with and without stent placement after percutaneous balloon angioplasty in hemodialysis patients.

Cephalic arch stenosis is a common complication in maintenance hemodialysis (MHD) patients with brachial artery-cephalic vein fistulas and frequently leads to loss of the functioning brachial artery-cephalic vein fistula. There is paucity of conclusive data to guide appropriate management. We examined the risk of recurrence of cephalic arch stenosis after angioplasty compared to angioplasty after stent placement determined by angiography of the involved upper extremity over time in a contemporary cohort of MHD patients treated in two interventional nephrology practices from March 2008 through May 2011. We retrospectively identified 45 MHD patients with evidence of cephalic arch stenosis (age 60 ± 30 years, 45% men) on elective angiograms. The median number of days until another angioplasty was required decreased, starting with a median of 91.5 days after the first, 70.5 days after the second, 85 days after the third, and 56 days after the fourth. Angioplasty is associated with a faster rate of recurrence of cephalic arch stenosis. The placement of intravascular stent seems to prolong the patency compared to angioplasty alone. Clinical trials with a larger sample size will better elucidate the value and timing of angioplasty versus stent placement in cephalic arch stenosis.

Outcomes of arteriovenous grafts following simultaneous thrombectomy and stent graft placement across the venous anastomosis.

Arteriovenous grafts (AVGs) suffer from high thrombosis rates. It is not known whether placement of stent grafts at the venous anastomosis (VA) of thrombosed AVGs would impact future thrombosis. This is a retrospective study evaluating a group of AVGs that underwent endovascular thrombectomy with placement of a stent graft at their VA. The study period was a minimum of 1 year or until kidney transplantation or death. Primary and secondary AVG patency rates were obtained using Kaplan-Meier survival estimates. Demographic parameters were analyzed using Cox multivariate analysis. The effect of early vs. late first thrombosis was also studied. Sixty-six patients were included in the study. Of these, 53 (80%) experienced ≥1 thrombotic event during the study period. Thrombosis led to AVG loss in 26 (39%). The primary patency was 47%, 35%, and 21% at 3, 6, and 12 months, respectively. The assisted primary patency was 50%, 38%, and 25% at 3, 6, and 12 months, respectively. The secondary patency rate was 85%, 76%, and 72% at 3, 6, and 12 months, respectively. Thus, poor primary patency rates were observed despite stent graft placement at the VA. In addition, early thrombosis following stent graft placement was associated with worse AVG outcomes.

A comparison between the HeRO graft and conventional arteriovenous grafts in hemodialysis patients.

Venous stenosis and occlusion are a major cause of vascular access dysfunction and failure. The HeRO Graft bypasses occlusion and traverses stenosis with outflow directly into the central venous circulation. A randomized, multicenter study was conducted to evaluate the efficacy and safety of the HeRO Graft relative to conventional AV grafts. The design was to enroll 143 patients in a 2:1 randomization ratio between HeRO and conventional AV control groups. Data on 72 subjects (52 HeRO Graft and 20 AV graft controls) were obtained. The HeRO Graft and control cohorts were comparable in baseline characteristics. Adequacy of dialysis, bacteremia rates, and adverse events were consistent between groups. Twelve month Kaplan-Meier estimates for primary and secondary patency rates were 34.8% and 67.6% in the HeRO Graft cohort, and 30.6% and 58.4% in the control cohort. There was no statistical difference in terms of patency between groups. The rates of intervention were 2.2/year for HeRO Graft and 1.6/year for the control (p = 0.100). Median days to loss of secondary patency was 238 for HeRO Graft versus 102 for the control (p = 0.032). The HeRO Graft appears to provide similar patency, adequacy of dialysis, and bacteremia rates to those of conventional AV grafts.

Acoustic tracking of Cassie to Wenzel wetting transitions.

Many applications involving superhydrophobic materials require accurate control and monitoring of wetting states and wetting transitions. Such monitoring is usually done by optical methods, which are neither versatile nor integrable. This letter presents an alternative approach based on acoustic measurements. An acoustic transducer is integrated on the back side of a superhydrophobic silicon surface on which water droplets are deposited. By analyzing the reflection of longitudinal acoustic waves at the composite liquid-solid-vapor interface, we show that it is possible to track the local evolution of the Cassie-to-Wenzel wetting transition efficiently, as induced by evaporation or the electrowetting actuation of droplets.

Characteristics of biofilm on tunneled cuffed hemodialysis catheters in the presence and absence of clinical infection.

BACKGROUND: Biofilm occurring on the surface of tunneled hemodialysis (HD) catheters is difficult to eradicate and often is associated with recurrent bacteremia. We studied biofilm formation on catheters from patients with and without bacteremia to identify the location of bacterial growth and measure biofilm thickness. STUDY DESIGN: Prospective observational study. SETTING & PARTICIPANTS: 76 adult HD patients; 26 had HD catheters removed for bacteremia and 50 had catheters removed for reasons other than infection. PREDICTORS: Segment of catheter, reason for catheter removal. OUTCOMES & MEASUREMENTS: Microbiological growth and biofilm thickness on the outer and luminal surfaces of extravascular and intravascular catheter segments. RESULTS: Catheter cultures were positive in 16 (62%) patients with bacteremia and 15 (30%) when the catheter was removed for non-infection-related reasons. In catheters with positive cultures, the outer surface of the extravascular segment was the most common site of bacterial growth (15/16 [94%] and 11/15 [73%] for bacteremic and nonbacteremic patients, respectively). Bacteremic patients had significantly thicker biofilm on all catheter surfaces, and in bacteremic patients, the biofilm was significantly thicker on the outer compared with the luminal surface for both extravascular (14.53 ± 6.17 vs 11.97 ± 5.01 µm; P < 0.001) and intravascular (12.21 ± 5.3 vs 9.46 ± 3.71 µm; P < 0.001) segments. Extravascular segments had significantly thicker biofilm compared with intravascular segments on both the outer (P < 0.001) and luminal (P < 0.001) surfaces. Similarly, in patients for whom the catheter was removed for non-infection-related reasons, the catheter had thicker biofilm on the outer compared with the inner surface in both extravascular (2.19 ± 2.84 vs 1.62 ± 2.33 µm; P < 0.001) and intravascular (1.92 ± 2.62 vs 1.29 ± 2.33 µm; P < 0.001) segments. Similar to catheters from bacteremic patients, the outer and luminal surfaces of the extravascular segments of the catheters had significantly thicker biofilm compared with their corresponding surfaces on the intravascular segments. LIMITATIONS: Observational study. CONCLUSIONS: The outer surface of the extravascular segment of tunneled dialysis catheters in both bacteremic and nonbacteremic HD patients has the thickest biofilm and highest microbiological yield, and biofilm is thicker in patients with bacteremia. This knowledge is important for designing preventive strategies and also in the management of patients with catheter infection.