Functional Patency Research Articles

Outcomes of three types of native arteriovenous fistula in a single center.

To study the outcomes of three different types of native arteriovenous fistula (AVF), the distal (D: radial-cephalic), middle-arm (MA: radial-cephalic) and proximal (P: brachial-cephalic) AVF access creation for hemodialysis patients in a single center. An 8-year retrospective review, from 2006 to 2014, was conducted at a single institution in which the surgical outcomes for three different types of native AVF creation were reviewed. Preoperative duplex vein mapping was obtained in all patients to choose the best vein and site for access. There were 317 patients identified with 41 D-AVFs, 120 MA-AVFs and 156 P-AVFs. Younger patients with a lower Charlson's Index were more frequent in the D-AVF group (p = 0.02). Mean operating room time was 15 minutes longer for the MA-AVF group than the two others (p = 0.018). Early failure (thrombosis at 30-day), one-year patency, one-year primary AVF functional patency for the D-AVF, MA-AVF, and P-AVF groups were 2.4% (n = 1), 8% (n = 1), 3.8% (n = 6), (p = 0.14); 97.6% (n = 39), 99% (n = 117), 89% (n = 129), (p<0.001); 80.5% (n = 33), 75.8% (n = 91), and 61.5% (n = 96) (p<0.001), respectively. Reintervention for fistula maturation was required in 17% (n = 7), 23% (n = 28), and 24% (n = 38) (p<0.01). The one-year venipuncture hematoma and steal syndrome occurrences were 9.7% (n = 4), 6.7% (n = 8), 3.8% (n = 6) (p = 0.06); and 0%, 0% and 3.8% (n = 6) (p = 0.04), respectively. In case of failure of either MA-AVF or D-AVF, a P-AVF was always feasible as a second native AVF hemodialysis access. D-AVF is still the gold-standard access for hemodialysis. If D-AVF is not possible, MA-AVF should be always investigated before committing to a P-AVF.

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.

Femoral Arteriovenous Grafts for Hemodialysis: Retrospective Comparison With Upper Extremity Grafts and Fistulas.

Background:Femoral arteriovenous grafts are rarely used to provide vascular access for dialysis patients. This is likely due, in part, to historically high rates of graft loss from infection and thrombosis. However, for selected patients who have exhausted all access options in the upper extremity, femoral grafts can provide additional sites for access creation and may be preferred over central venous catheters.Objective:We sought to demonstrate that femoral grafts can provide a reliable and safe alternative to central venous catheters for selected patients.Methods:A single-center retrospective review in Vancouver, Canada, from April 1, 2008, to March 31, 2012, was conducted. All patients with new arteriovenous access (grafts and fistulas) created during the study period were included in the study population and followed for a minimum of 2 years. Comparisons of patency (primary, secondary, and functional) and complications (infectious and noninfectious) were made between the different access types.Results:Thirteen patients with femoral grafts were compared with 22 patients with arm grafts and 384 patients with fistulas. Femoral grafts had higher rates of thrombosis (46% with a thrombotic event) and a higher requirement for interventions (1.3 angioplasties and 0.12 thrombolytic procedures per patient per year). However, compared with arm grafts, femoral grafts had superior secondary and functional patency. No difference in patency was seen when comparing femoral grafts with upper extremity fistulas. Only 2 patients with femoral grafts required antibiotics for infection, and no grafts were lost to infection.Conclusions:For patients with limited access options remaining, femoral grafts may provide an additional form of vascular access before resorting to catheter use. Our study shows that with appropriate patient selection, femoral grafts have low infection rates and patency that is comparable with other access types.

Basilic vein transposition: A viable alternative for multiple failed arteriovenous fistulas - A single center experience.

Primary use of the autogenous arteriovenous access is recommended by the National Kidney Foundation-Dialysis Outcomes Quality Initiative guidelines. In spite of troublesome comorbidities associated with basilic vein transposition (BVT), it is still the most preferred technique when autologous veins are not suitable to construct radio-cephalic fistula (RCF) and brachiocephalic fistula (BCF), arteriovenous fistula (AVF). The present study highlights our experience with BVT, with small incision technique, over a period of two years with excellent outcome. This retrospective study included all the patients who underwent BVT at our tertiary care center between March 2013 and March 2015. It was performed in patients with failed previous RCF or BCF or who had small caliber or thrombosed cephalic veins. The patients with minimum 3 mm basilic vein diameter on Doppler were only included in the study. A 3-cm horizontal incision was made in antecubital fossa to expose brachial artery and basilic vein. Multiple longitudinal separate second skin incisions (2-3 cm) were made to explore proximal part of basilic vein. Side branches of the vein were isolated and ligated. The divided basilic vein in antecubital fossa was brought over fascia through newly created subcutaneous tunnel followed by end-to-side anastomosis. A total of 18 (12 males and 6 females) underwent BVT in the two years period. The mean fistula maturation time was 42 ± 10 days. Maturation rate was 100%, and the postoperative flow rate was 290 ± 22 (mL/min). No bleeding, thrombosis, failure, pseudo aneurysm, or rupture occurred in our patients. Arm edema occurred in ix (33%) patients, infection in three (17%), and lymphorrhea in five (28%). The mean follow-up was six months. BVT is an alternative method with excellent initial maturation and functional patency rates requiring less extensive skin incision and surgical dissection. It is the most durable hemodialysis access procedure for those patients having multiple forearm AVF surgeries.

Closed cervix is associated with more severe illness in dogs with pyometra.

BackgroundPyometra, a life-threatening bacterial infection of the uterus, is classified as open or closed depending on the functional patency of the cervix i.e. presence or absence of vaginal discharge. In closed cervix pyometra, pus and bacterial products accumulate in the uterus, which is thought to induce a more severe illness. The aim of this study was to investigate whether disease severity or outcome differed in dogs with open or closed cervix pyometra.ResultsProspectively collected data from 111 female dogs diagnosed with pyometra at the University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, intermittently during 2005–2012 was analyzed. Seventy-two dogs (65%) had open cervix, whereas 39 dogs (35%) had closed cervix. Differences between the two groups were explored by Wilcoxon Two Sample Test for continuous variables and Chi-square or Fisher’s exact test for categorical variables. P < 0.05 was considered significant.In dogs with open cervix the median age was 9.0 years and the median weight 26.0 kg. In dogs with closed cervix the median age was 9.6 years and the median weight 25.0 kg, with no significant differences between the groups (p = 0.69 and 0.24, respectively). Five dogs (4.5%) died, all with open cervix, and 16 dogs (14%) had complications.The general physical condition was moderately or severely depressed in 30% (21/71) of dogs with open cervix (severely depressed in 4 dogs, moderately depressed in 17 dogs) and in 56% (22/39) of dogs with closed cervix (severely depressed in 3 dogs, moderately depressed in 19 dogs). The general physical condition was mildly depressed in 41 dogs with open cervix and 16 dogs with closed cervix, whereas it was normal in nine dogs with open cervix and one dog with closed cervix. None of the included dogs had very severely depressed general physical condition or were non-responsive.Leukocytosis, neutrophilia, monocytosis and moderately to severely depressed general condition was more commonly found in dogs with closed cervix (p = 0.003, p = 0.008, p = 0.003 and p = 0.006, respectively).Sepsis was more commonly present in closed cervix pyometra (77%, 30/39 dogs) compared to open cervix pyometra (51%, 36/71 dogs) (p = 0.007). Presence of prolonged postoperative hospitalization did not differ significantly between the two groups.ConclusionsIn dogs with closed cervix, sepsis was more common, the general physical condition more often moderately to severely depressed and leukocytosis, neutrophilia and monocytosis more frequently found. The results showed that closed cervix was associated with a more severe illness than open cervix at admission but not with poorer outcome as measured by postoperative hospitalization. These findings may be clinically valuable for optimizing monitoring and treatments in dogs with the disease.

UPPER ARM BASILIC VEIN TRANSPOSITION FOR HEMODIALYSIS: WHAT IS THE OPTIMAL TECHNIQUE?

Objective: The brachiobasilic arteriovenous fistula (BBAVF) can be formed in one or two stages. This study examined the failure rates and functional patencies of one-stage vs two-stage brachiobasilic transposition fistulas to compare the two surgical techniques. Patients and methods: 50 BB fistulae (25 single and 25 two-stage) were created over a 3year period (2012-2015). Data including sex, age, dialysis and diabetic status was collected from the case notes. Patency and time to maturity data was collected prospectively from the dialysis unit. Results: During the study interval, 100 brachiobasilic transpositions (50 one-stage and 50 two-stage) were performed in 100 patients. Patients undergoing the two-stage procedure tended to be older (mean 49 vs 53 years; P = 0.8). The two-stage BBAVFs had significantly better primary (88% vs 92%; P=0.58), and secondary functional (92% vs 96%; P=0.508.) patencies. Pre-HD fistula has better patency than post-HD fistula (100% vs 90%; p=0.015) Conclusion: This study describes a series of BBAVFs and makes comparison between the one-stage and two-stage operations. Significantly improved overall functional patency is demonstrated for the two-stage operation. Keywords: Brachiobasilic, Fistula, Transposition

Initial clinical experience with a polytetrafluoroethylene vascular dialysis graft reinforced with nitinol at the venous end

ObjectiveThe purpose of this study was to examine the outcomes of a vascular hybrid polytetrafluoroethylene (PTFE) graft, provided with a nitinol-reinforced section (NRS) on one end, in hemodialysis vascular access placement. MethodsA retrospective study was conducted including all the consecutive patients who underwent Gore Hybrid Vascular Graft (GHVG; W. L. Gore & Associates, Flagstaff, Ariz) implantation for hemodialysis access placement between October 2013 and November 2015. A propensity-matched control group was obtained from consecutive patients who underwent standard PTFE arteriovenous graft implantation between January 2010 and July 2013. The selection criteria were inadequate venous material for autogenous arteriovenous fistula placement, patent deep venous circulation, and vein diameter of 4 to 8.5 mm. The implantation technique involves the insertion of the NRS some centimeters into the target vein. Fluoroscopic guidance helps deploy the device in the desired landing zone (ie, position of the proximal end of the NRS), based on anatomic landmarks. Survival, functional patency rates, and complications were compared with a propensity-matched historical control group. Vein diameter, previous vascular access placement, and diabetes were tested as predictors of reintervention with a logistic regression analysis. ResultsThere were 32 patients (14 men; mean age, 69 ± 14 years) who received the GHVG graft. The historical control group included 43 patients. Technical success was 100%. The graft configuration was brachial-axillary (n = 22 [69%]), brachial-basilic loop (n = 5 [16%]), brachial-antecubital loop (n = 3 [9%]), axilloaxillary loop (n = 1 [3%]), and femoral-femoral loop (n = 1 [3%]). Mean NRS oversize was 20% ± 7% (range, 3%-34%; median, 19%). Perioperative complications requiring revision included acute limb ischemia treated with thrombectomy (n = 1 [3%]) and graft infection requiring explantation (n = 2 [6%]). Two patients (6%) died in the hospital of unrelated causes. The mean follow-up was 15 ± 11 months (range, 0-33 months; median, 15.5). The propensity-matched groups included 25 patients each. Survival estimates at 24 months for the GHVG and standard PTFE groups were 91% ± 6% and 82% ± 9% (P > .05), respectively. The 12-month patency estimates were as follows: functional primary patency, 66% ± 10% vs 51% ± 10% (P > .05); functional assisted primary patency, 75% ± 9% vs 51% ± 10% (P > .05); and functional secondary patency, 79% ± 9% vs 67% ± 10% (P > .05). Reduction in vein diameter was associated with reintervention. ConclusionsThe GHVG is a safe and effective alternative to standard PTFE in hemodialysis access surgery. Careful planning for the landing zone is advisable, especially for small outflow veins. Larger studies and randomized trials are needed to define the role for this device. A study including a greater number of centers experienced with this device is currently under way.

COMPARATIVE STUDY BETWEEN ONE-STAGE AND TWO- STAGE BRACHIO BASILIC ARTERIOVENOUS FISTULA AS A HEMODIALYSIS ACCESS PROCEDURE

Background: The primary use of autogenous arteriovenous access for chronic hemodialysis is recommended by the National Kidney Foundation–Dialysis Outcomes Quality Initiative practice guidelines. Brachiaobasilic (BB) fistulae are a form of vascular access for patients requiring dialysis. Brachiaobasilic (BB) fistulae can be created with either a single stage or a two stage procedure. Objective: The goal of this study was to compare the failure rates and functional patencies of one-stage vs two-stages brachiobasilic fistulas. Patients and Methods: Fifty patients with chronic renal failure (CRF) with the cephalic vein was unsuitable for use or failed brachio cephalic were admitted to The Vascular Surgery Unit in Al-Hussein University Hospital in the period from Jun. 2011 to Jun 2013.One stage procedure was done to twenty five patients of them and two stages procedure was done to the rest of the patients. Results: Two stages procedure failure rates were lower than one stage procedure. Two stage procedure survived longer than one stage procedure. There was no difference in primary failure between the two groups which were due to hypotension, thrombosis of vein , and small sized basilic vein. Two cases of wound infection had occurred in obese and diabetic patients which was controlled by drainage and umbrella of antibiotics. Conclusion: Two stage procedure BB fistulae was better than one stage procedure in primary patency and access survival.

Endoscopic management of congenital choanal atresia: Second look is mandatory

Congenital choanal atresia (CA) is a rare abnormality characterized by unilateral or bilateral obstruction of the posterior end of the nasal cavity. With an incidence of 1:1000 to 1:8000 births, it is more in female than in males and unilateral more common than bilateral. Surgical procedures aim to provide adequate functional choanal patency and a low rate of rest enosis, with shorter surgery and hospitalization times, to minimize morbidity and mortality, this study done to evaluate the effectiveness and safety of endoscopic nasal surgical techniques for the treatment of congenital choanal atresia in patients with unilateral and bilateral atresia and to emphasis in the important of second look procedure at the time of removal of stent to assess the wideness of neochoana, and to remove any granulation tissue ,or polyps, it involved 13 patients, 10 with unilateral CA and 3 bilateral CA, all involved in surgery and second look.Bangladesh J Otorhinolaryngol; October 2015; 21(2): 76-79

Brachiobasilic fistulae: an upper limb autologous option for everyone?

Purpose Autologous arteriovenous fistulae (AVF) are the vascular access option of choice. However, Brachiobasilic fistula (BBF) are complex procedures with variable outcomes reported in the literature. Our aim was to evaluate outcomes and morbidity associated with BBF in our population. Methods Retrospective analysis of prospectively collected data was undertaken for all 51 BBF created in our institution between January 2010 and March 2013. These were compared to an age and sex-matched group of brachiocephalic fistula (BCF) created over a similar time period. Demographic, operative and outcome data was collected for all patients. The primary end points were primary functional patency, primary-assisted patency and secondary patency at 3, 6 and 12 months. Continuous data was compared using Student’s t-test and categorical data using chi-squared test (p < 0.05 is significant). Results Mean patient age was 57 years (range: 21–82). About 45% were male. About 73% of patients were already on hemodialysis (HD) at the time of BBF creation. BBF was the secondary or tertiary access procedure in 60.8% of patients (n = 31). BBF were associated with significant operative burden with 82% of patients requiring a general anaesthetic and median hospital admission of 2 days (range: 1–4). About 75% had a single-stage procedure. About 23.5% (n = 12) required operative revision (superficialization or anastomotic revision for stenosis). Patients with BBF spent an additional 3.45 days/year in hospital as a result of access related complications compared to 0.56 days/year in the BCF group. Primary-assisted patency at 3, 6 and 12 months was better in the BCF group than BBF group (86%, 72% and 48% vs. 71%, 59%, 33%, respectively; p < 0.01) Primary functional and secondary patency rates at 3, 6 and 12 months were 74%, 58% and 32% and 78%, 63% and 41%, respectively, with an average of 0.33 procedures per AVF to maintain patency (10 fistuloplasties, 4 IR thrombectomy and 3 surgical thrombectomy). About 32% (n = 17) of BBF were never used for HD (seven patients had a patent AVF but did not require HD >18 months following creation; nine failed to adequately mature and one patient refused second stage superficialization). Conclusions BBF are associated with a significant initial operative burden and higher complication and poorer patency rates than BCF. About one-third of BBF created in this series were never used. Given the morbidity associated with this procedure, careful consideration should be given to creation of BBF in pre-dialysis patients particularly those in whom the rate of decline in renal function is slow.

Investigating clinical predictors of arteriovenous fistula functional patency in a European cohort.

BackgroundArteriovenous fistula (AVF) failure to mature (FTM) rates contribute to excessive dependence on central venous catheters for haemodialysis. Choosing the most appropriate vascular access site for an individual patient is guided largely by their age, co-morbidities and clinical examination. We investigated the clinical predictors of AVF FTM in a European cohort of patients and applied an existing clinical risk prediction model for AVF FTM to this population.MethodsA prospective cohort study was designed that included all patients undergoing AVF creation between January 2009 and December 2014 in a single centre (Belfast City Hospital) who had a functional AVF outcome observed by March 2015.ResultsA total of 525 patients had a functional AVF outcome recorded and were included in the FTM analysis. In this cohort, 309 (59%) patients achieved functional AVF patency and 216 (41%) patients had FTM. Female gender [P < 0.001, odds ratio (OR) 2.03 (CI 1.37–3.02)] and lower-arm AVF [P < 0.001, OR 4.07 (CI 2.77–5.92)] were associated with AVF FTM. The Lok model did not predict FTM outcomes based on the associated risk stratification in our population.ConclusionsIn this European study, female gender was associated with twice the risk of AVF FTM and a lower-arm AVF with four times the risk of FTM. The FTM risk prediction model was not found to be discriminative in this population. Clinical risk factors for AVF FTM vary between populations; we would recommend that units investigate their own clinical predictors of FTM to maximize AVF functional patency and ultimately survival in dialysis patients. Clinical predictors of AVF FTM may not be sufficient on their own to improve vascular access functional patency rates.

A randomized controlled trial of interrupted versus continuous suturing techniques for radiocephalic fistulas

Continuous suturing techniques have conventionally been used for the end-to-side anastomoses of radiocephalic fistulas (RCFs); however, primary patency rates are poor. Only 50% to 60% of RCFs ever achieve functional patency. We hypothesized that a hybrid interrupted-continuous suturing technique (as used in many microsurgical procedures) may improve outcomes in fistulas constructed from small vessels. A randomized controlled trial comparing hybrid interrupted-continuous (n = 42) with continuous (n = 36) suturing techniques for RCF was undertaken. Patients were excluded if vessels were <1.8 mm in diameter or if previous ipsilateral fistula had been attempted. A priori power calculation indicated that a sample size of 78 patients was required to detect an improvement in patency from 50% to 80% (α = .05, β = .8). The primary end point was primary patency at 6 weeks (assessed by a blinded observer for the presence of thrill and bruit). Secondary end points were immediate patency, functional patency (assessed clinically and by ultrasound) at 6 weeks, and presence of anastomotic stenosis. Groups were comparable for basic patient demographics, operating surgeon, and vessel diameter as measured on preoperative ultrasound (mean age, 58.9 ± 13 years; 68% male). Primary patency at 6 weeks was higher in the hybrid interrupted-continuous suturing technique group (71% vs 47%; P = .01). Immediate patency was also higher in the hybrid interrupted-continuous suturing technique group (93% vs 67%; P < .001). There was no significant difference in functional patency at 6 weeks (52% vs 36%; P = .18). Three patients developed an anastomotic stenosis. All were in the hybrid interrupted-continuous suturing technique group. One patient from the interrupted suturing technique cohort required re-exploration for bleeding. A hybrid interrupted-continuous suturing technique yielded higher immediate and 6-week primary patency rates for RCF. The hybrid interrupted-continuous suturing technique may improve anastomotic compliance and reduce the narrowing and puckering that can occur on suture tightening in small-caliber vessels. Based on these findings, consideration should be given to performing hybrid interrupted-continuous anastomoses for RCFs.

Diagnostic Values and Outcomes of Patency Capsule in Patients With Known or Suspected Intestinal Strictures

Introduction: Video capsule endoscopy (VCE) is a standard tool for evaluating small bowel (SB) diseases. The most common complication of VCE is capsule retention. The most common cause of retention is SB stricture. Patency capsule (PC) is a self-dissolving capsule used to assess functional patency of the SB before VCE. However, data on the predictive values of PC are scarce. The purpose of our study was to evaluate the performance of PC in patients with known or suspected SB strictures and to identify predictive parameters of PC failure. Methods: At our institution, a tertiary academic center, we perform more than 1,000 VCEs each year. Inclusion criteria for this study included 306 patients with known or suspected SB strictures between 2009 and 2015 who had a PC study. Data on passage and failure of PC study and the clinical, imaging and laboratory parameters of these patients were collected. The patients with retained VCE (n=15) and/or surgery (n=4) were considered the reference standard for clinically significant luminal strictures. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, positive (PLR) and negative (NLR) likelihood ratios, and ROC curve with 95% confidence intervals (CI) were calculated. A p value < 0.05 was considered statistically significant. Results: Among the 306 patients, 43 patients (14%) failed to pass PC. Of the 43 patients, 21 (48.8%) had prior abdominal surgeries, 10 (23.3%) had chronic use of NSAIDs, and 8 (18.6%) had suspected or known Crohn's disease. 7 patients (16.3%) reported abdominal symptoms with PC failure, while the other 36 reported no symptoms. There were no statistical differences in the clinical parameters, including concurrent opioid use and diabetes, and laboratory parameters, including CRP and ESR, between the patients who passed (n=263) and who failed to pass PC (n=43). The sensitivity, specificity, PPV, NPV, PLR and NLR with their respective CIs for PC examination are detailed in Table 1. The AUC estimate of ROC curve was 0.51. Conclusion: While the sensitivity is low, the high specificity and NPV of the PC examination suggests that patients with suspected or known SB strictures can undergo VCE safely if PC has passed, thereby making it a useful test prior to VCE.Table 11

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.

Heparin-Bonded Polytetrafluorethylene Does Not Improve Hemodialysis Arteriovenous Graft Function

Heparin-bonded polytetrafluorethylene (hep PTFE), when compared with standard PTFE, has been shown to have a modest improvement in distal extremity bypass grafts. The data supporting its usage for dialysis access are less clear. We compared the patency rates, number of interventions, and complications between hep PTFE grafts and nonheparin-bonded PTFE (nonhep PTFE) grafts placed for dialysis access. A retrospective review of all dialysis access procedures between January 2013 and March 2014 entered into a prospectively maintained vascular surgery database was performed. Our primary end point was functional graft patency. Secondary end points were primary, primary assisted, and secondary patency, as well as time to graft abandonment, and number of procedures required to maintain or restore graft patency. The number of interventions required to maintain graft patency and graft-related complications were also reviewed. Kaplan-Meier curves were used to compare the 2 groups. Between January 2013 and March 2014, 301-dialysis access procedures were performed, which included 70 arteriovenous grafts (AVGs) comprised 32 hep PTFE (32, 6-mm straight grafts) and 38 nonhep PTFE (35, 4-7-mm taper and 3, 6-mm straight). Mean follow-up was 7.35 ± 5.15 months. At 1 year, Kaplan-Meier survival curves showed that functional patency between hep PTFE and nonhep PTFE AVG were 60% and 75%, respectively (P = 0.37). Primary and secondary patencies were not significantly different between groups; however, primary-assisted patency was significantly improved at 1 year (hep PTFE versus nonhep PTFE: 50% vs. 80%; P = 0.02). The number of hep PTFE grafts undergoing percutaneous thrombectomy was significantly higher than the nonhep PTFE grafts (11 vs. 2; P = 0.009). The incidence and time to graft abandonment were not statistically different. The same was true for the number of complications between the 2 groups. Multivariate analysis showed nonhep PTFE AVG to be advantageous for primary and primary-assisted patency. We did not demonstrate a benefit to the routine use of hep PTFE for AVG creation especially given the higher cost of these grafts. Functional patency rates were not improved, and the rates of reintervention and thrombectomy were higher with hep PTFE AVGs.

The Omega-3 fatty acids (Fish Oils) and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) study: the updated final trial protocol and rationale of post-initiation trial modifications.

BackgroundThe FAVOURED study is an international multicentre, double-blind, placebo-controlled trial which commenced recruitment in 2008 and examines whether omega-3 polyunsaturated fatty acids (omega-3 PUFAs) either alone or in combination with aspirin will effectively reduce primary access failure of de novo arteriovenous fistulae (AVF) in patients with stage 4 and 5 chronic kidney disease. Publication of new evidence derived from additional studies of clopidogrel and a high screen failure rate due to prevalent aspirin usage prompted an updated trial design.Methods/designThe original trial protocol published in 2009 has undergone two major amendments, which were implemented in 2011. Firstly, the primary outcome ‘early thrombosis’ at 3 months following AVF creation was broadened to a more clinically relevant outcome of ‘AVF access failure’; a composite of thrombosis, AVF abandonment and cannulation failure at 12 months. Secondly, participants unable to cease using aspirin were allowed to be enrolled and randomised to omega-3 PUFAs or placebo. The revised primary aim of the FAVOURED study is to test the hypothesis that omega-3 PUFAs will reduce rates of AVF access failure within 12 months following AVF surgery. The secondary aims are to examine the effect of omega-3 PUFAs and aspirin on the individual components of the primary end-point, to examine the safety of study interventions and assess central venous catheter requirement as a result of access failure.DiscussionThis multicentre international clinical trial was amended to address the clinically relevant question of whether the usability of de novo AVF at 12 months can be improved by the early use of omega-3 PUFAs and to a lesser extent aspirin. This study protocol amendment was made in response to a large trial demonstrating that clopidogrel is effective in safely preventing primary AVF thrombosis, but ineffective at increasing functional patency. Secondly, including patients taking aspirin will enrol a more representative cohort of haemodialysis patients, who are significantly older with a higher prevalence of cardiovascular disease and diabetes which may increase event rates and the power of the study.Trial registrationAustralia & New Zealand Clinical Trial Register (ACTRN12607000569404)

Higher Patency of Transposed Brachio-Basilic Arteriovenous Fistulas Compared to Brachio-Axillary Grafts for Hemodialysis Patients

We compared outcomes of transposed brachio-basilic arteriovenous fistulas (BBAVF) with brachio-axillary prosthetic grafts (BAPG) for hemodialysis. All consecutive patients who underwent creation of a BBAVF or a BAPG, in one of the two institutions, between January 2008 and December 2013 were retrospectively identified. We assessed functional patency and compared complication rates. Patency was also compared between one-stage and two-stage creation procedures for the BBAVF group. Two hundred and thirty-eight patients underwent the creation of a BBAVF (N = 136) or a BAPG (N = 102). Median follow-up was 17 months (range, 1-79). At 6, 12 and 24 months, patients in the BBAVF group had significantly higher primary patency (80%, 69%, 56% vs. 77%, 56%, 37%, respectively; p = 0.005), assisted primary patency (90%, 80%, 71% vs. 80%, 66%, 48%; p&lt;0.0001) and secondary patency (93%, 84%, 72% vs. 94%, 87%, 62%; p = 0.006). Two-stage BBAVF had a significantly higher secondary patency (98%, 92%, 78% vs. 90%, 80%, 68%; p = 0.04) than one-stage BBAVF. The rate of infectious complications was significantly lower in the BBAVF group than in the BAPG group (0.8% vs. 6.9%; p = 0.03). In this large cohort, BBAVF had a higher functional patency and lower rate of infectious complications than BAPG. After exhaustion of cephalic veins, we suggest creation of a BBAVF instead of BAPG, whenever anatomically feasible. The superiority of one-stage or two-stage BBAVF creation procedure must be further investigated.

Increased use of brachiocephalic arteriovenous fistulas improves functional primary patency

As vascular surgeons strive to meet the Fistula First Initiative, some authors have observed a decrease in arteriovenous fistula (AVF) maturation rates in association with an increase in AVF creation. In May 2012, we adopted a practice change in an attempt to maintain the same high level of AVF creation while leading to a decrease in fistula failures. A retrospective study was conducted of all dialysis access procedures performed by a single vascular surgeon before (period 1; before May 1, 2012) and after (period 2; after May 1, 2012) the change in practice pattern. The adopted change included favoring the brachiocephalic location unless the patient was an ideal anatomic candidate for a radiocephalic AVF, creating a larger and standardized arteriotomy, and using a large venous footplate whenever possible. The main outcome measure was primary functional patency at 1 year. Secondary outcome measures included primary patency at 1 year, time to maturation, type of fistula created, steal syndrome, and tunneled hemodialysis catheter infections. Of 213 vascular access procedures performed, 191 (90%) were AVFs. There was no difference in use of AVFs between period 1 (93% AVFs) and period 2 (88% AVFs; P = .2). Use of brachiocephalic AVFs increased from 38% in period 1 to 56% in period 2 (P = .01), with a corresponding trend toward a decrease in radiocephalic AVFs in period 2 (36% in period 1 to 27% in period 2; P = .2). Primary functional patency at 1 year was 47% in period 1 and 63% in period 2 (P = .03). Primary patency at 1 year was 51% in period 1 and 70% in period 2 (P = .001). Time to reach functional maturation was decreased in period 2 (median, 76 vs 82.5 days; P = .046). There was no difference in steal syndrome (P = 1.0), and the incidence of hemodialysis catheter infections was lower in period 2 (0 vs 7 [7%]; P = .006). Increasing brachiocephalic AVF creation and reducing our reliance on radiocephalic AVFs resulted in a significant increase in primary functional patency at 1 year. This was achieved while maintaining the same high percentage of fistulas, a lower rate of central catheter infections, and the same low incidence of steal syndrome.

Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline.

This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy (ESGE). The Guideline was also reviewed and endorsed by the British Society of Gastroenterology (BSG). It addresses the roles of small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders. Main recommendations 1 ESGE recommends small-bowel video capsule endoscopy as the first-line investigation in patients with obscure gastrointestinal bleeding (strong recommendation, moderate quality evidence). 2 In patients with overt obscure gastrointestinal bleeding, ESGE recommends performing small-bowel capsule endoscopy as soon as possible after the bleeding episode, optimally within 14 days, in order to maximize the diagnostic yield (strong recommendation, moderate quality evidence). 3 ESGE does not recommend the routine performance of second-look endoscopy prior to small-bowel capsule endoscopy; however whether to perform second-look endoscopy before capsule endoscopy in patients with obscure gastrointestinal bleeding or iron-deficiency anaemia should be decided on a case-by-case basis (strong recommendation, low quality evidence). 4 In patients with positive findings at small-bowel capsule endoscopy, ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by capsule endoscopy (strong recommendation, high quality evidence). 5 ESGE recommends ileocolonoscopy as the first endoscopic examination for investigating patients with suspected Crohn's disease (strong recommendation, high quality evidence). In patients with suspected Crohn's disease and negative ileocolonoscopy findings, ESGE recommends small-bowel capsule endoscopy as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known stenosis (strong recommendation, moderate quality evidence).ESGE does not recommend routine small-bowel imaging or the use of the PillCam patency capsule prior to capsule endoscopy in these patients (strong recommendation, low quality evidence). In the presence of obstructive symptoms or known stenosis, ESGE recommends that dedicated small bowel cross-sectional imaging modalities such as magnetic resonance enterography/enteroclysis or computed tomography enterography/enteroclysis should be used first (strong recommendation, low quality evidence). 6 In patients with established Crohn's disease, based on ileocolonoscopy findings, ESGE recommends dedicated cross-sectional imaging for small-bowel evaluation since this has the potential to assess extent and location of any Crohn's disease lesions, to identify strictures, and to assess for extraluminal disease (strong recommendation, low quality evidence). In patients with unremarkable or nondiagnostic findings from such cross-sectional imaging of the small bowel, ESGE recommends small-bowel capsule endoscopy as a subsequent investigation, if deemed to influence patient management (strong recommendation, low quality evidence). When capsule endoscopy is indicated, ESGE recommends use of the PillCam patency capsule to confirm functional patency of the small bowel (strong recommendation, low quality evidence). 7 ESGE strongly recommends against the use of small-bowel capsule endoscopy for suspected coeliac disease but suggests that capsule endoscopy could be used in patients unwilling or unable to undergo conventional endoscopy (strong recommendation, low quality evidence).

Previous Hemodialysis Access Improves Functional Outcomes of the Proximal Radial Artery Fistula in Males

The proximal radial artery fistula (PRA) has been established as an early viable surgical option for arteriovenous fistula creation. The overall assisted primary patency reported in the literature approaches 100% at 1 year. We hypothesize that this excellent patency does not represent a functional result when seen in light of successful cannulation and fistula utilization. We retrospectively queried our Veterans Administration Hospital operative database to identify 284 male patients who had 571 access procedures performed by a senior vascular surgeon attending (R.K.D.) from January 1, 2003, to December 31, 2008. Operative details, patient comorbidities, fistula maturation time (time to first cannulation), functional patency (date of access to abandonment, revision to another fistula type, conversion to a prosthetic graft, thrombosis of the fistula, conversion to peritoneal dialysis, renal transplant, or patient death), and total duration (creation of the fistula to the end of its functional patency) were collected and analyzed. A total of 144 PRAs were placed during the study period. In all, 87 patients underwent primary proximal radial artery fistula (P-PRA) placement in a limb without previous access; 57 patients had a secondary proximal radial artery fistula (S-PRA) after a failed previous fistula or graft in the same limb. There were no differences between the 2 groups in terms of age, comorbidities, and operative details. A total of 91 patients (63.2%) were receiving hemodialysis at the time of P-PRA or S-PRA placement. Outcomes of P-PRA and S-PRA populations on hemodialysis were examined. There was increased cannulation success (33% vs. 55%; P = 0.00354, Fisher's exact test), functional patency (755.2 ± 661.2 days vs. 405.4 ± 531.9 days; P = 0.0220, Wilcoxon two-sample test), and total duration (859.5 ± 650.7 days vs. 516.8 ± 547.2 days; P = 0.0361, Wilcoxon two-sample test) of S-PRA over P-PRA. There was no difference in endovascular interventions between the 2 groups (1.6 ± 1.0 interventions per access versus 1.1 ± 0.7 interventions per access; P = 0.2109, Wilcoxon two-sample test). Subgroup analysis (analysis of variance) of the S-PRA group indicated that a patent but failing previous access in the same arm was not superior in terms of successful cannulation, functional patency, or total duration when compared with a thrombosed previous access. The PRA remains a viable first access procedure undertaken at our institution. Compared with the reported 12-month assisted primary patency of this fistula type, we found a small percentage of PRAs actually being accessed for successful hemodialysis treatment. The S-PRA appears to have a significantly higher successful cannulation rate, functional patency, and total duration time when compared with the P-PRA in patients receiving hemodialysis treatments. The mechanism of these improved outcomes is not known; considering patency or thrombosis of a previous access in the S-PRA group did not predict future access success in the same extremity.