Primary Unassisted Patency Research Articles

Association between statin intensity and femoropopliteal stent primary patency in peripheral arterial disease

BackgroundStatins are widely used in coronary and peripheral arterial disease, but their impact on patency of stents placed for peripheral arterial disease is not well-studied. The purpose of this study was to evaluate femoropopliteal stent primary patency according to statin intensity at the time of stent placement and compare this effect to other covariates that may influence stent patency.Materials and methodsA retrospective review identified 278 discrete femoropopliteal stent constructs placed in 216 patients over a 10-year period; Rutherford categories were 2 (3.6%), 3 (12.9%), 4 (21.2%), 5 (49.6%), and 6 (12.6%). Stent locations were common femoral (1.8%), common femoral/superficial femoral (0.7%), superficial femoral (50.7%), superficial femoral/popliteal (32.7%) and popliteal (14.0%) arteries; 63.3% of stents were paclitaxel-eluting. Primary patency of each stent construct was determined with duplex ultrasound, angiography, or computed tomographic angiography. Greater than 50% restenosis or stent occlusion was considered loss of patency. Cox proportional hazard and Kaplan–Meier modeling were used to assess the effect of statin use and additional covariates on stent patency.ResultsPatients on any statin at the time of stent placement were half as likely to undergo loss of primary unassisted patency as patients on no statin therapy (hazard ratio, 0.53; 95% confidence interval, 0.19–0.87; P = .004). Moderate/high intensity statin therapy conferred 17 additional months of median stent patency compared to the no statin group. Antiplatelet therapy, anticoagulant therapy, drug-eluting stents (versus bare metal or covered stents), and Rutherford class were not predictive of stent patency (P = 0.52, 0.85, 0.58, and 0.82, respectively).ConclusionUse of statin therapy at the time of femoropopliteal stent placement was the most predictive examined variable influencing primary unassisted patency.

Radiofrequency guidewire-facilitated recanalization of chronic thoracic central venous occlusions in hemodialysis patients

PurposeTo assess the outcome and safety of radiofrequency (RF) wire recanalization in patients with end-stage renal disease (ESRD) and chronic central venous occlusions (CVO).Materials and MethodsA retrospective review of ESRD patients who underwent RF-wire recanalization of symptomatic chronic thoracic CVO from January 2017 to August 2022 yielded 20 patients who underwent 21 procedures. All patients had undergone at least one prior unsuccessful attempt at central venous recanalization using conventional catheter-based techniques. Technical success was defined by the ability to cross the CVO using RF-wire recanalization enabling endovascular treatment. Access circuit patency was evaluated based on follow-up imaging and symptomatic improvement.ResultsRadiofrequency wire recanalization was successful in 17/21 procedures (81%) with all patients (100%) reporting resolution of arm ± facial swelling. Three major complications occurred (14%): two hemothoraces and one hemopericardium. Medial stent diameter was 13 mm (range, 9–14 mm). Mean duration of hospital stay was 2 days ± 3 days. Mean procedure time was 158 ± 46 min with a mean fluoroscopy time of 31.7 ± 16.3 min. Primary unassisted patency at 6 and 12 months was 94 ± 6% and 85 ± 10%, respectively. Additional interventions resulted in significantly increased stent graft patency (P = 0.006).ConclusionRadiofrequency wire-enabled recanalization of CVO in symptomatic dialysis patients has a high rate of technical success with resolution of arm and facial swelling and resumed use of the ipsilateral dialysis access. Although a superior safety profile was seen than with needle-based techniques such as sharp recanalization, major complications were not infrequent indicating that this RF-wire procedure should be performed in centers equipped to manage central venous perforations.

Prospective multicenter study of a novel endovascular venous anastomotic procedure and device for implantation of an arteriovenous graft for hemodialysis.

The traditional sutured venous anastomosis used during arteriovenous graft implantation is associated with a high incidence of subsequent stenosis that is attributed to neointimal hyperplasia. Hyperplasia results from multiple factors, including hemodynamic abnormalities and vessel trauma during implantation. A novel anastomotic connector device was designed to provide an alternative, less traumatic, endovascular venous anastomosis that may ameliorate the clinical challenges associated with a sutured anastomosis. A prospective single-arm multicenter study was performed to evaluate safety and effectiveness of graft implantation using the study device. Patients requiring graft creation and who met the study criteria were enrolled between February 2018 and July 2021 and observed for 6 months. Collected data included baseline characteristics, graft patency and use for hemodialysis, graft interventions, and adverse events. The primary study endpoint was cumulative graft patency, compared to a pre-specified Performance Goal of 75%. Secondary endpoints included primary unassisted patency and serious adverse events, defined as the occurrence of death, graft infection, emergent surgery, significant bleeding, and pseudoaneurysm. A total of 158 patients were enrolled from 10 study sites, among which 144 subjects were evaluable at 6 months and 14 were censored with partial follow-up observation. Three patients died and the graft was abandoned in 12. The primary endpoint was met (p-value < 0.001). By Kaplan Meier survival analysis, cumulative patency was 92.08% with a lower 95% Confidence Bound of 86.98%. Primary unassisted patency was 60.21% with a lower 95% Confidence Bound of 50.84%. Graft infections occurred in six patients, all unrelated to the study device. There were no reports of emergent surgery, significant bleeding or pseudoaneurysm. These results demonstrate that the study device can be used for successful endovascular anastomosis of a vein to a graft for hemodialysis, with acceptable cumulative patency and safety profile at 6 months. ClinicalTrials.gov Identifier: NCT02532621.

Abstract No. 29 Tunneled Dialysis Catheter Placement within Intensive Care Unit (ICU) Patients: Influence of Catheter Tip Design on Clinical Performance

Tunneled dialysis catheter tip design may affect freedom from catheter dysfunction and/or infection; improved performance within a critical care setting may reduce costs and need for catheter guidewire exchange or removal. This study compared rates of catheter failure between a symmetrical, helical-tip catheter (VectorFlow) with a conventional split-tip catheter (Ash-Split) among ICU patients undergoing tunneled dialysis catheter placement. A retrospective database identified a total of 1734 tunneled dialysis catheters placed at an academic institution over a 7-year period. Of these, 340 catheters (19.6%) were placed within ICU patients, which included VectorFlow (n = 112, 32.9%) and Ash-Split (n = 228, 67.1%) catheters. Rates of catheter failure requiring guidewire exchange or removal from a composite outcome of malfunction or infection were compared with Kaplan-Meier estimates, and covariates potentially influencing catheter failure were assessed with Cox proportional hazards modeling. Catheter failure occurred within 90 days in 34.8 ± 3.4% of ICU patients. Among patients with VectorFlow catheters, primary unassisted patency at 30, 60, 90 and 180 days was 87.4 ± 3.6%, 78.0 ± 5.1%, 75.1 ± 5.0% and 60.1 ± 8.2% compared with 75.0 ± 3.3%, 62.8 ± 4.1%, 60.7 ± 4.2% and 44.3 ± 5.5% among patients with Ash-Split catheters (P = 0.022). Cox modeling of body mass index, patient age, sex, left jugular (vs. right) placement and indication for placement (initiation of hemodialysis access vs. failed surgical arteriovenous access) showed no effect on catheter patency; patients with Ash-Split catheters had a hazard ratio of catheter failure 1.72 times higher than patients with VectorFlow catheters (P = 0.024) in univariate modeling and a hazard ratio of 1.81 in multivariate modeling (P = 0.017). The VectorFlow catheter was associated with significantly higher rates of primary patency than the Ash-Split catheter among ICU patients, independent of multiple clinical and anatomic factors. These data support a VectorFlow-first placement strategy within this patient population.

Modified no-touch technique for radio-cephalic arteriovenous fistula increases primary patency and decreases juxta-anastomotic stenosis.

Low primary patency rate is a major problem of radio-cephalic arteriovenous fistula (RC-AVF) creation. Radial artery deviation and reimplantation (RADAR) is associated with low juxta-anastomotic stenosis rate. However, inflow artery stenosis is prominent with RADAR. To further reduce injury to veins and arteries during operation, a modified no-touch technique (MNTT) was used to create RC-AVF. We retrospectively reviewed our prospectively maintained database of patients with end-stage renal disease (ESRD)s undergoing RC-AVF creation for hemodialysis using either the MNTT between January 2021 and January 2022 (MNTT group) or conventional surgical procedure ( end-to-side vein-to-artery anastomosis) between October 2016 and October 2017 (Control group). Patients who chose to undergo RC-AVF surgery underwent standardized preoperative mapping and postoperative fistula evaluations using duplex ultrasound. Additionally, 4D flow MRI data were used to visualize and quantify the hemodynamics of one RC-AVF by MNTT. Outcomes included primary patency, juxta-anastomotic stenosis, and maturation rates. Forty patients underwent RC-AVFs by MNTT, compared to 60 patients in the control group. The MNTT group had a higher primary unassisted patency rate than the control group (p = 0.038). Juxta-anastomotic stenosis (all on the cephalic vein) occurred in 4 (10%) patients who underwent MNTT. RC-AVF maturation rates after 3 months were not different between both groups (maturation rate: 90% and 81.7% in the MNTT and control groups, respectively, p = 0.253). COX regression showed that both conventional AVF surgery (p = 0.031) and smaller cephalic vein diameter (p = 0.034) were associated with higher odds of RC-AVF failure. The AVF flow within the proximal vein remained helical during cardiac cycle. The distribution of wall shear stress (WSS) and oscillatory shear index (OSI) differed from that of conventional surgical AVF. RC-AVF by MNTT increases primary patency rate and decreases juxta-anastomotic stenosis rate. The improvement in hemodynamics may be one of the important reasons for the better patency rate of in the RC-AVF by MNTT group.

Hemodialysis Access Type and Access Patency Loss: An Observational Cohort Study

Access patency outcomes for arteriovenous fistulas (AVFs) as compared with arteriovenous grafts (AVGs) in patients receiving hemodialysis (HD) who have achieved a functioning permanent access are not fully explored. Observational cohort study. Fee-for-service Medicare beneficiaries aged≥18 years with kidney failure who were newly using a permanent access for maintenance HD from the United States Renal Data System (2010-2015). Patients using an oral anticoagulant were excluded. AVG or AVF. Loss of primary unassisted, primary assisted, and secondary patency. Outcomes were characterized using cumulative incidence curves, and HRs adjusted for sociodemographic and clinical factors were estimated for the comparison of AVF versus AVG. The cohort included 60,329 and 17,763 patients newly using an AVF and AVG, respectively, for HD. Over 3 years of follow-up, AVG users, compared to AVF users, had a higher cumulative incidence of loss of primary unassisted patency (87% vs 69%; HR, 1.56; 95% CI, 1.52-1.60), loss of primary assisted patency (69% vs 25%; HR, 3.79; 95% CI, 3.67-3.92), and loss of secondary patency (22% vs 10%; HR, 2.03; 95% CI, 1.92-2.16). Stratified analyses revealed differences by subgroups; in particular, incidence of patency loss was higher among patients who underwent prior interventions to maintain prefunctional access patency and Black patients. This analysis focused on outcomes occurring after first successful use of a permanent access and thus does not inform about risk of patency loss during access maturation. Among patients with kidney failure who successfully used a permanent access for HD, patency loss was consistently substantially higher in those using AVGs compared with AVFs. New interventions, such as prophylactic drugs, are needed to improve access longevity and reduce the need for invasive interventions, particularly among patients unable to receive a fistula.

Preoperative Cardiac Index as a Predictor of Maturation and Primary Patency of Radiocephalic Arteriovenous Fistula in Hemodialysis

Background: Radiocephalic arteriovenous fistula (RCAVF) is the best access modality to be considered initially when planning arteriovenous fistula (AVF) for maintenance hemodialysis. Considering the higher incidence of RCAVF failed maturation (M), it is important to perform proper preoperative evaluation and identification of high-risk patients. There has been no study on the influence of preoperative cardiac function on the M and patency of AVFs. The purpose of this investigation is to determine whether preoperative cardiac index (CI) is a predictor of M and primary patency of RCAVF. Method: A total of 365 end-stage renal disease patients undergoing RCAVF surgery were consecutively enrolled with a median follow-up time of 20 months in this prospective cohort study. Demographics, vascular diameters measured by duplex ultrasound examination, and CI measured by echocardiography, were analyzed for effect on RCAVF primary functional M and primary patency. Result: Patients in the group achieving primary RCAVF functional M had a significantly larger mean CI than the group with early RCAVF failure (2.93 ± 0.77 vs. 3.57 ± 0.76 L/min/m², p < 0.001). The receiver operating characteristic curve was plotted and demonstrated that preoperative vein diameter and CI can predict failure of RCAVF M. The AUC of CI was higher (0.745 vs. 0.666). Multivariate regression analysis, adjusted for age, sex, diabetes, preoperative dialysis status and vessel diameters, showed that decreased CI remained associated with increased risk of failure of M (FM) and worse primary unassisted patency. The Kaplan-Meier survival analysis suggested that patients with CI <3 L/min/m² had a worse primary unassisted patency rate at all time points compared with patients with CI ≥3 L/min/m². Conclusion: This study demonstrated that preoperative CI was associated with RCAVF M and long-term patency. A decreased CI may be a possible predictor of an increased risk of FM and a shorter primary patency time.

Antiplatelet agents for chronic kidney disease.

Antiplatelet agents are widely used to prevent cardiovascular events. The risks and benefits of antiplatelet agents may be different in people with chronic kidney disease (CKD) for whom occlusive atherosclerotic events are less prevalent, and bleeding hazards might be increased. This is an update of a review first published in 2013. To evaluate the benefits and harms of antiplatelet agents in people with any form of CKD, including those with CKD not receiving renal replacement therapy, patients receiving any form of dialysis, and kidney transplant recipients. We searched the Cochrane Kidney and Transplant Register of Studies up to 13 July 2021 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. We selected randomised controlled trials of any antiplatelet agents versus placebo or no treatment, or direct head-to-head antiplatelet agent studies in people with CKD. Studies were included if they enrolled participants with CKD, or included people in broader at-risk populations in which data for subgroups with CKD could be disaggregated. Four authors independently extracted data from primary study reports and any available supplementary information for study population, interventions, outcomes, and risks of bias. Risk ratios (RR) and 95% confidence intervals (CI) were calculated from numbers of events and numbers of participants at risk which were extracted from each included study. The reported RRs were extracted where crude event rates were not provided. Data were pooled using the random-effects model. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We included 113 studies, enrolling 51,959 participants; 90 studies (40,597 CKD participants) compared an antiplatelet agent with placebo or no treatment, and 29 studies (11,805 CKD participants) directly compared one antiplatelet agent with another. Fifty-six new studies were added to this 2021 update. Seven studies originally excluded from the 2013 review were included, although they had a follow-up lower than two months. Random sequence generation and allocation concealment were at low risk of bias in 16 and 22 studies, respectively. Sixty-four studies reported low-risk methods for blinding of participants and investigators; outcome assessment was blinded in 41 studies. Forty-one studies were at low risk of attrition bias, 50 studies were at low risk of selective reporting bias, and 57 studies were at low risk of other potential sources of bias. Compared to placebo or no treatment, antiplatelet agents probably reduces myocardial infarction (18 studies, 15,289 participants: RR 0.88, 95% CI 0.79 to 0.99, I² = 0%; moderate certainty). Antiplatelet agents has uncertain effects on fatal or nonfatal stroke (12 studies, 10.382 participants: RR 1.01, 95% CI 0.64 to 1.59, I² = 37%; very low certainty) and may have little or no effect on death from any cause (35 studies, 18,241 participants: RR 0.94, 95 % CI 0.84 to 1.06, I² = 14%; low certainty). Antiplatelet therapy probably increases major bleeding in people with CKD and those treated with haemodialysis (HD) (29 studies, 16,194 participants: RR 1.35, 95% CI 1.10 to 1.65, I² = 12%; moderate certainty). In addition, antiplatelet therapy may increase minor bleeding in people with CKD and those treated with HD (21 studies, 13,218 participants: RR 1.55, 95% CI 1.27 to 1.90, I² = 58%; low certainty). Antiplatelet treatment may reduce early dialysis vascular access thrombosis (8 studies, 1525 participants) RR 0.52, 95% CI 0.38 to 0.70; low certainty). Antiplatelet agents may reduce doubling of serum creatinine in CKD (3 studies, 217 participants: RR 0.39, 95% CI 0.17 to 0.86, I² = 8%; low certainty). The treatment effects of antiplatelet agents on stroke, cardiovascular death, kidney failure, kidney transplant graft loss, transplant rejection, creatinine clearance, proteinuria, dialysis access failure, loss of primary unassisted patency, failure to attain suitability for dialysis, need of intervention and cardiovascular hospitalisation were uncertain. Limited data were available for direct head-to-head comparisons of antiplatelet drugs, including prasugrel, ticagrelor, different doses of clopidogrel, abciximab, defibrotide, sarpogrelate and beraprost. Antiplatelet agents probably reduced myocardial infarction and increased major bleeding, but do not appear to reduce all-cause and cardiovascular death among people with CKD and those treated with dialysis. The treatment effects of antiplatelet agents compared with each other are uncertain.

Anaesthesia Choice for Creation of Arteriovenous Fistula (ACCess) study protocol : a randomised controlled trial comparing primary unassisted patency at 1 year of primary arteriovenous fistulae created under regional compared to local anaesthesia

IntroductionArteriovenous fistulae (AVF) are the ‘gold standard’ vascular access for haemodialysis. Universal usage is limited, however, by a high early failure rate. Several small, single-centre studies have demonstrated better early...

Indications for a “Surgery First” Approach for the Treatment of Lower Extremity Arterial Disease

In recent years, a tendency has developed toward an “endovascular first” approach for the treatment of or femoropopliteal arterial disease. The goal of our study was to determine which patients' long-term patency of femoropopliteal bypass (FPB) would be significant enough that they would be better served with initial primary surgical intervention. A retrospective analysis of all patients undergoing FPB from June 2006 to December 2014 was performed. Our primary endpoint was primary unassisted graft patency, defined as patent on ultrasound or angiography or a palpable pulse in the bypass on physical examination. The patients with <1 year of follow-up were excluded. We identified 241 patients who had undergone FPB on 272 limbs. The mean follow-up was 7.1 years. The FPB indication was disabling claudication in 95 limbs, critical limb ischemia (CLI) or wounds in 148 limbs, and popliteal aneurysm in 29 limbs. Of the 272 FPBs, 134 used saphenous vein grafts (SVGs), 126 used prosthetic grafts, 8 used arm vein grafts, and 4 used cadaveric or xenografts. Of the FPBs, 97 were patent for ≥5 years. Statistically significant factors for 5-year patency were use of SVG conduits (P = .01), male sex (P = .023), age <70 years (P = .003), white race (P = .014), no diabetes (P = .014), no history of chronic obstructive pulmonary disease (COPD; P = .001), and no history of cerebrovascular accident (P = .005). Grafts patent at 5 years were more likely to have been performed for claudication (5-year patency, 63.4%) or a popliteal aneurysm (73.1%) compared with critical limb ischemia or wounds (38.2%; P < .0001). The FPB conFiguration (above or below the knee, in situ vs reversed saphenous vein) was not significant for 5-year patency. SVG (P = .004), male sex (P = .034), a surgical indication of claudication or popliteal aneurysm (P < .0001), white race (P < .0001), and no history of COPD (P = .026) were statistically significant (log-rank test) for patency over time (Figs 1 and 2). Of the 272 FPBs, 23 were performed in white, non-COPD, nondiabetic, male patients without a history of cerebrovascular accident who had received SVG conduits for claudication or a popliteal aneurysm. The 5-year patency for those 23 FPBs was 91%. Young, nondiabetic, white male patients without diabetes or COPD and with an accepTable saphenous vein undergoing FPB grafting for claudication or a popliteal aneurysm are likely to have a patent FPB at 5 years and might be best served by an initial surgical procedure.Fig 2Kaplan-Meier curve for primary unassisted patency comparing men and women.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Is fetuin-A a biomarker of dialysis access dysfunction?

The arteriovenous (AV) access function of hemodialysis (HD) patients can be impaired by afferent artery stiffness due to preexisting microcalcification and by venous stenosis secondary to neointimal hyperplasia in whose development participates an upregulated local inflammatory process. Fetuin-A is a circulating potent inhibitor of vascular calcification and plays an important anti-inflammatory role. The aims of this prospective study were to investigate the relationship between baseline serum fetuin-A levels and: blood flow (QA) values at baseline, AV access failure (thrombosis or intervention for stenosis) during follow-up and primary unassisted AV access patency. We measured baseline serum fetuin-A levels and QA values of the AV access in 64 HD patients under routine QA surveillance for stenosis. Patients were classified into tertiles according to their baseline fetuin-A levels (g/L): <0.5 (tertile-1), 0.5-1.20 (tertile-2), and >1.20 (tertile-3). Fetuin-A was positively correlated with QA (Spearman coefficient = 0.311, p = 0.012). Fourteen patients (21.9%) underwent AV access failure and they had lower fetuin-A (0.59 ± 0.32 g/L) and lower QA (739.4 ± 438.8 mL/min) values at baseline compared with the remaining patients (1.05 ± 0.65 g/L and 1273.0 ± 596.3 mL/min, respectively) (p = 0.027 and p < 0.001, respectively). The AV access failure rate was highest (34.8%) in tertile-1 (lowest fetuin-A level). Unadjusted Cox regression analysis showed a decrease in the risk of AV access patency loss by increasing fetuin-A concentration (hazard ratio 0.395 (95% confidence interval: 1.42-1.69), p = 0.044) but it was not confirmed in the adjusted model, although the hazard ratio was low (0.523). Kaplan-Meier analysis showed that patients in tertile-3 (highest fetuin-A concentration) had the highest primary unassisted AV access patency (λ2 = 4.68, p = 0.030, log-rank test). If our results are confirmed in further studies, fetuin-A could be used as a circulating biomarker to identify HD patients at greater risk for AV access dysfunction, who would benefit from much closer dialysis access surveillance.

Abstract No. 29 Percutaneous mesocaval shunt creation: a retrospective review of 5 patients with midterm outcomes

To evaluate the indication, approach, safety, and outcomes of percutaneous mesocaval shunt placement Institutional review board-approved retrospective review of the electronic medical records of patients with percutaneous mesocaval shunts was performed from January 2001 through March 2020 (n = 5). Indication for mesocaval shunt placement was refractory variceal hemorrhage in all 5 patients. All patients had extensive portal vein thrombosis (PVT) (1 intrahepatic, 4 extrahepatic) precluding transjugular intrahepatic portosystemic shunt placement. The underlying etiologies for PVT were non-alcoholic cirrhosis, primary sclerosing cholangitis, pancreatic cancer, post-surgical, and during pregnancy of indeterminate etiology. Post-procedurally, patients were followed for up to 10 years with clinical and laboratory assessment as well as CT or MRI imaging. Technical success was defined as placement of a stent from the superior mesenteric vein to the inferior vena cava. Clinical success was defined as cessation of refractory bleeding. Patient demographics, technical approach for placement, pre-procedure and post-procedure MELD scores, shunt patency, and complications were recorded. Technical and clinical success was achieved in 100% (5 of 5) of patients. Procedural imaging was available for 4/5 patients. To perform the inferior vena cava to superior mesenteric vein puncture, a combination of fluoroscopy and intravascular ultrasound was used in 25% (1/4), fluoroscopy and transabdominal ultrasonography was used in 25% (1/4), and fluoroscopy and intracardiac echocardiography was used in 50% (2/4). MELD scores (9 – 29) did not significantly deviate from pre-procedure to 30 days post-procedure in any patient. Mesocaval shunt primary unassisted patency was 5/5 (100%) at 6 months, 4/4 (100%) at 12 and 18 months, and 2/3 (67%) at 24 months. After 32 months, one patient underwent intentional mesocaval shunt closure for chronic, refractory hepatic encephalopathy (HE). The final patient maintained mesocaval shunt patency for greater than 10 years. No immediate complications occurred peri-procedurally. Two patients (40%) suffered HE, one of which resolved with medical optimization and the second required eventual shunt closure. Mesocaval shunt placement is an uncommonly performed procedure to treat complications of portal hypertension when a TIPS cannot be placed. In this cohort, outcomes were comparable to TIPS as it was safe, well tolerated, and remained patent in a majority of patients at 24 months.

Contemporary outcomes of a “snuffbox first” hemodialysis access approach in the United States

ObjectiveThe Society for Vascular Surgery guidelines for permanent hemodialysis (HD) access creation recommend prioritizing the most distal possible autogenous access to minimize complications and preserve more proximal options. The “snuffbox” arteriovenous fistula (AVF) is the most distal radial artery–cephalic vein AVF. Despite the theoretical benefits of the snuffbox approach, recent trends have been toward upper arm access. Our study sought to investigate the feasibility of a snuffbox-first strategy for HD access in all anatomically appropriate candidates. MethodsFrom January 2016 to August 2019, all patients with end-stage renal disease (ESRD) or pre-ESRD under consideration for HD access were evaluated for a snuffbox-first approach by a team of vascular surgeons and nephrologists at a single, urban academic medical center in the United States. Data were collected prospectively and supplemented by medical record review. A survival analysis was performed to evaluate primary unassisted and secondary patency and clinical and functional maturation. Patients were censored if they had received a kidney transplant or had died. Cox proportional hazards regression was used to determine the risk factors for prolonged clinical maturation and functional maturation. ResultsA total of 55 snuffbox AVFs were created. The median patient age was 60 years (interquartile range [IQR], 52-70 years), and 52.7% of the patients were men. The median follow-up was 369 days (IQR, 166-509 days). The median survival for primary unassisted patency was 90 days (95% confidence interval [CI], 79-111). Secondary patency at 1 year was 92.3% (95% CI, 85.3%-99.9%). The clinical maturation rate at 1 year was 83.7% (n = 55; 95% CI, 66.8%-91.9%), and the functional maturation rate at 1 year was 85.6% (n = 40; 95% CI, 63.3%-94.4%). Of the patients who were pre-ESRD at AVF creation and had initiated HD during the study period, 87.5% had successfully received incident HD with their snuffbox AVF. Twenty-four patients were receiving HD via a catheter at snuffbox creation. Of those patients, the functional maturation rate at 1 year was 82.5% (95% CI, 44.8%-94.4%). The patients had undergone a median of two interventions (IQR, zero to seven interventions) in the first year. Of these, 46.9% were percutaneous angioplasty and 31.2% were side-branch ligation. Diabetes was associated with slower AVF clinical maturation (multivariate hazard ratio, 0.35; 95% CI, 0.15-0.82; P = .016). A larger artery diameter was associated with earlier AVF clinical maturation (multivariate hazard ratio, 6.64; 95% CI, 2.11-20.9). ConclusionsA snuffbox-first approach to HD access is a viable option for distal access creation in a cohort of patients requiring HD in the United States. Subsequent ancillary interventions to facilitate access maturation were required for most patients.

PATENCY-2 trial of vonapanitase to promote radiocephalic fistula use for hemodialysis and secondary patency.

Arteriovenous fistulas created for hemodialysis often fail to become usable and are frequently abandoned. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in increasing radiocephalic fistula use for hemodialysis and secondary patency. PATENCY-2 was a randomized, double-blind, placebo-controlled trial in patients on or approaching the need for hemodialysis undergoing radiocephalic arteriovenous fistula creation. Of 696 screened, 613 were randomized, and 603 were treated (vonapanitase n = 405, placebo n = 208). The study drug solution was applied topically to the artery and vein for 10 min immediately after fistula creation. The primary endpoints were fistula use for hemodialysis and secondary patency (fistula survival without abandonment). Other efficacy endpoints included unassisted fistula use for hemodialysis, primary unassisted patency, fistula maturation and unassisted maturation by ultrasound criteria, and fistula procedure rates. The proportions of patients with fistula use for hemodialysis was similar between groups, 70% vonapanitase and 65% placebo, (p = 0.33). The Kaplan-Meier estimates of 12-month secondary patency were 78% (95% confidence interval [CI], 73-82) for vonapanitase and 76% (95% CI, 70-82) for placebo (p = 0.93). The proportions with unassisted fistula use for hemodialysis were 46% vonapanitase and 37% placebo (p = 0.054). The Kaplan-Meier estimates of 12-month primary unassisted patency were 50% (95% CI, 44-55) for vonapanitase and 43% (95% CI, 35-50) for placebo (p = 0.18). There were no differences in the proportion of patients with fistula maturation or in fistula procedure rates. Adverse events were similar between groups. Vonapanitase was not immunogenic. Vonapanitase treatment did not achieve clinical or statistical significance to meaningfully improve radiocephalic fistula surgical outcomes. Outcome in the placebo group were better than in historical controls. Vonapanitase was well-tolerated and safe. clinicaltrials.gov: NCT02414841 (https://clinicaltrials.gov/ct2/show/NCT02414841).

A Novel Hybrid Silk Fibroin/Polyurethane Arteriovenous Graft for Hemodialysis: Proof-of-Concept Animal Study in an Ovine Model.

To solve the problem of vascular access failure, a novel semi-degradable hybrid vascular graft, manufactured by electrospinning using silk fibroin and polyurethane (Silkothane), has been previously developed and characterized in vitro. This proof-of-concept animal study aims at evaluating the performances of Silkothane grafts in a sheep model of arteriovenous shunt, in terms of patency and short-term remodeling. Nine Silkothane grafts are implanted between the common carotid artery and the external jugular vein of nine sheep, examined by palpation three times per week, by echo-color Doppler every two weeks, and euthanized at 30, 60, and 90 days (N = 3 per group). At sacrifice, grafts are harvested and submitted for histopathology and/or scanning electron microcopy (SEM). No cases of graft-related complications are recorded. Eight of nine sheep (89%) show 100% primary unassisted patency at the respective time of sacrifice (flow rate 1.76±0.61L min-1 , one case of surgery-related thrombosis excluded). Histopathology and SEM analysis evidence signs of inflammation and pseudointima inside the graft lumen, especially at the venous anastomosis; however, endoluminal stenosis never impairs the functionality of the shunt and coverage by endothelial cells is observed. In this model, Silkothane grafts grant safety and 100% patency up to 90 days.

Short interposition with a small-diameter prosthetic graft for flow reduction of a high-flow arteriovenous fistula

ObjectiveThe objective of this study was to evaluate the outcome of a short interposition using a small-diameter prosthetic graft as a flow-limiting procedure to manage symptomatic high-flow arteriovenous fistula (AVF). MethodsA retrospective review of medical records on a case series was conducted. From June 2004 to April 2017, there were 25 patients with clinical symptoms of high output cardiac failure and progressive dilation of aneurysmal fistula vein due to high-flow AVF (≥1.5 L/min) who underwent short interposition with a 5-mm prosthetic graft at Saitama Medical Center. The primary outcome was the relief of clinical symptoms; other outcome measures included technical success, surgical complications, patency of vascular access, and postoperative changes in local and systemic hemodynamics as assessed by Doppler ultrasound. ResultsTwenty-five patients underwent short interposition for cardiac indications (n = 16) and aneurysmal dilation (n = 9). The technical success rate was 100%. The clinical symptoms were relieved in 24 patients (96.0%). Mean reduction in access blood flow was 52.4%. Cumulative primary unassisted patency rates (± standard error) at 1 year, 2 years, and 3 years were 76.2% ± 9.3%, 70.4% ± 10.3%, and 58.1% ± 11.6%, respectively. Secondary patency rates (± standard error) at 1 year, 2 years, and 3 years were 81.8% ± 8.2%, 71.5% ± 9.9%, and 71.5% ± 9.9%, respectively. Complications included access occlusion due to late thrombosis (n = 5 [21.7%]) and graft infection (n = 1 [4.3%]) in the median follow-up period of 3.9 years. ConclusionsShort interposition with a prosthetic graft is a simple, effective, and durable treatment option for end-stage renal disease patients with cardiac symptoms and progressive dilation of the fistula vein due to high-flow AVF, offering clinical symptom resolution while preserving the autologous behavior of the initial access.

Diagnosis and Treatment of Nonmaturing Fistulae for Hemodialysis Access via Transradial Approach: A Case-Control Study

PurposeTo compare outcomes of transradial access for endovascular treatment of nonmaturing hemodialysis fistulae compared to brachial arteriography followed by unidirectional or bidirectional fistula access for intervention. Materials and MethodsIn this institutional review board-approved, retrospective, case-control study, 56 consecutive patients with nonmaturing arteriovenous fistulae underwent percutaneous intervention between 2015 and 2018. The transradial group (n = 28) underwent radial artery access for diagnostic fistulography and intervention. The control group (n = 28) underwent retrograde brachial artery access for fistulography followed by unidirectional/bidirectional fistula access for intervention. Both groups had similar demographics, fistula characteristics, and stenosis locations. ResultsFewer punctures were required in the transradial group compared to controls (1.2 vs 2.4, P < .0001), and procedure time was shorter (64.9 vs 91.3 minutes, P = .0016). Anatomic, technical, and clinical success rates trended higher in the transradial group compared to controls (93% vs 86%, 96% vs 89%, and 82% vs 64%, respectively). Nonmaturation resulting in fistula abandonment was lower in the transradial group (3.7% vs 25%, P = .025). Primary unassisted patency at 3, 6, and 12 months was 77.1% ± 8.2%, 73.1% ± 8.7%, and 53.3% ± 10.6% in the transradial group, respectively, and 63.0% ± 9.3%, 55.6% ± 9.6%, and 48.1% ± 9.6% in the control group, respectively (P = .76). Primary assisted patency at 12 months was 92.3% ± 5.3% in the transradial group compared to 61.8% ± 9.6% at 12 months in the control group (P = .021). No major complications occurred. Minor complications were lower in the transradial group than in the control group (14% vs 39%, P = .068). ConclusionsTreatment of nonmaturing fistulae via a transradial approach was safe, improved midterm patency, and was associated with lower rates of fistula abandonment.

A Novel Hybrid Silk Fibroin/Polyurethane Arteriovenous Graft for Hemodialysis: Proof‐of‐principle Animal Study in an Ovine Model

BACKGROUNDIn an attempt at answering the need for a valuable and durable hemodialysis vascular access, a novel semi‐degradable hybrid vascular graft, manufactured by electrospinning using silk fibroin and polyurethane (Silkothane®), has been developed and characterized in vitro according to standards.OBJECTIVESIn this proof‐of‐principle animal study, we aimed at evaluating the performances of Silkothane® grafts in a sheep model of arteriovenous shunt, with respect to patency and short‐term graft remodeling.MATERIALS AND METHODSNine Silkothane® grafts (6mm inner diameter, ≈7cm long, ≈400μm thick) were surgically placed into the left cervical fossa of nine female sheep, between the common carotid artery and the external jugular vein. During the housing period the animals were treated with an inhibitor of platelets aggregation. Grafts were examined by palpation three times per week, and by duplex ultrasound every two weeks to exclude significant stenosis, dilation, presence of thromboses, neointimal proliferation or other complicating features. The sheep were euthanized at 30, 60 and 90 days (N=3 for each group). At sacrifice, grafts were harvested, fixed, and submitted for histologic, immunohistochemical and Scanning Electron Microscopy examination.RESULTSNo cases of graft‐related complications (e.g. seroma formation, transgraft bleeding, aneurismal dilation, calcification, structural yielding) were recorded in this study. One graft failed due to a thrombotic event likely related to a technical error (11%). One sheep had post‐operative wound infection, surgically resolved (11%). Four out of nine sheep (44%) showed post‐operative edema, usually disappearing in 7 days. Eight of nine sheep (89%) showed 100% primary unassisted patency at the respective time of sacrifice, as confirmed by palpation and ultrasound evaluation (average flow rate 1.76 ± 0.61 l/min). Histological, immunoistochemical and SEM analysis evidenced signs of inflammation and formation of neointimal hyperplasia at the venous anastomosis, as it typically happens with arteriovenous fistulae and synthetic grafts.CONCLUSIONSIn our ovine model of arteriovenous shunt, Silkothane® grafts provided evidences of safety and efficacy in granting 100% patency up to 90 days. Further studied need to be conducted in order to directly compare the novel grafts with commercially available synthetic grafts.

Longevity and infection free survival of permicath

Abstract Background A hemodialysis catheter is a small biocompatible tube made of soft flexible material. It is inserted into a patient’s target vein to provide vascular access for hemodialysis. As important as catheter placing and handling guide-lines to prevent infection reporting standards are equally important, as they are the tools to enable us to evaluate our work attitudes, how much are we sticking to the guide-lines, how are we managing our resources, and are we aware of the resources we have or not. Aim of the Work to figure the outcome and infection rate related to tunneled-cuffed catheters in patients with ESRD needing dialysis who were submitted to tunneled cuffed catheter placement during the period from May 2017 to April 2018. Patients and Methods This retrospective descriptive study was conducted in 35 TTCs patients in the Vascular Surgery department ASU Hospital. Target population included patients of ESRD who were submitted for tunneled cuffed dialysis catheter placement in the Vascular Surgery department ASU Hospital in the period from May 2017 to April 2018. Results A total of 35 TCCs were inserted in end-stage renal disease patients for hemodialysis. Total number of catheter days was 6343 days. The primary unassisted patency rates at 6 months and 1 year were 51.4% and 11.4% respectively. Of the 35 cases 19 (54.28% of the total population) reported infection episode. 5 (26.3% of the infected population) TCCs were removed due to a severe episode of BSI, of the removed TCCs 2 (10.5% of the infected population) were died. The TCC bacteraemia rate was 2.186 per 1000 catheter days. The total number of the removed TCCs was 14 (40% of the total population). The reasons for removal were non-patency, infection, and completion of therapy with percentage of 22, 8%, 14.3%, and 2, 9% respectively. Conclusion Tunnelled cuffed haemodialysis catheters are vital line of treatment in patients requiring long term haemodialysis especially elderly population with weak vasculature or consumed peripheral accesses in which it is considered an access of choice.

A relationship of intradialytic blood pressure variability with vascular access outcomes in patients on hemodialysis.

Vascular access dysfunction is a major cause of morbidity in patients with end-stage renal disease (ESRD) on hemodialysis (HD). Thus, identifying risk factors for vascular access failure is important. Patients on HD are routinely exposed to high blood pressure variability (BPV) during HD. However, the impact of intradialytic BPV on vascular access outcomes is unknown. Therefore, we investigated the association of intradialytic BPV with vascular access outcomes in patients on HD. One hundred and thirty patients with ESRD who created vascular access for HD were evaluated. We examined 12 dialysis sessions per patient and recorded BP five times for each session. BPV was assessed using residual standard deviation derived from the linear regression model. The patients were divided into two groups according to a level below or above the median value of intradialytic BPV and compared. The primary outcome was primary unassisted vascular access patency. The median time to loss of primary unassisted patency was significantly longer in low intradialytic BPV group than in high intradialytic BPV group (52 months vs. 21 months, P < 0.001) during the mean follow-up of 3.7 years. After adjustment for other variables, high intradialytic BPV was significantly associated with loss of primary unassisted vascular access patency (hazard ratio, 2.605; 95% confidence interval, 1.462-4.643; P = 0.001). Our study revealed a significant correlation between intradialytic BPV and vascular access patency. Further studies are needed to identify methods for lowering BPV.