Access Patency Research Articles

Long-term Outcomes of Stenting Superior Cava and Brachio-cephalic Vein Occlusion in Hemodialysis Patients with Arteriovenous Fistulas

Central vein occlusion (CVO) is a significant complication in patients undergoing chronic hemodialysis, often leading to dialysis inefficacy, disabling symptoms, and, most critically, major risk of access failure. While stenting has been proposed as a technique to maintain vascular access patency following the recanalization of occluded central veins, the data supporting its long-term efficacy remains limited. This study aims to evaluate the long-term effectiveness of stenting occluded superior vena cava (SVC) and/or brachiocephalic veins (BCV) to preserve vascular access patency, ensure continued dialysis efficacy and relieve SVC syndrome. This study retrospectively reviewed all hemodialysis patients who underwent stent placement for central venous occlusion between January 2017 and August 2024 at two vascular centers in Reunion Island. The primary endpoints of the study were the primary, assisted primary, and secondary patency rates of the vascular circuit during follow-up. Additionally, patient demographics, medical comorbidities, post-operative complications, definitive access abandonment and re-interventions were analyzed. This study included 21 patients with a mean age of 67 years. CVO stenting initially provided symptomatic relief for all patients, resolving symptoms such as superior vena cava or arm swelling in symptomatic patients. Over a median follow-up period of 41 months (range: 3-80 months), the primary patency rates were 67% at 12 months, 42% at 24 months and 38% at 36 months, while the secondary patency rates were 90%, 79%, and 60% at these same intervals. Twelve patients (62%) experienced clinically significant stent restenosis, necessitating one or several additional percutaneous transluminal angioplasty (PTA) during follow-up, while five patients (24%) developed acute access thrombosis requiring thrombectomy and PTA, with central stent involved for 3 patients. Three patients (14%) required extra-anatomic bypasses due to definitive stent occlusion, five patients (14%) had definitive access failure and five patients (24%) died from unrelated causes. This review suggests that hemodialysis patients with symptomatic central vein occlusion can often be successfully recanalized and treated with stenting, leading to symptom resolution and, importantly, achieving promising secondary patency rates. Our long-term results highlight the necessity for regular reintervention and close follow-up, as a significant number of patients will experience restenosis, and ultimately definitive access failure. Therefore, CVO stenting should be considered a temporary solution, although for some patients, this strategy may prove highly effective, maintaining long-term patency without any restenosis.

Effect of preoperative heart failure on arteriovenous access patency and prognosis in patients on hemodialysis.

The risk of arteriovenous (AV) access failure is associated with hemodynamic factors, clinical factors, or technical issues. Although several studies have shown the detrimental effects of AV access on heart function, few studies have assessed whether heart function affects AV access patency. We investigated the impact of cardiac function on AV access patency. Additionally, we evaluated the influence of heart failure (HF) on the prognosis of patients on dialysis. Patients who underwent dialysis and had echocardiographic reports between 2011 and 2013 were retrospectively included. Left ventricular ejection fraction (LVEF) was used to measure cardiac function. Data on demographics, clinical features, and technical factors associated with AV access surgery were collected. Univariate and multivariate analyses were performed to evaluate the risk factors for AV access patency loss and the prognosis of patients on dialysis. During the study period, 395 patients initiated on dialysis underwent echocardiography. In multivariate analysis, older age (hazard ratio (HR) 1.02 (1-1.03), p = 0.028), smoking (HR 2.05 (1.19-3.53), p = 0.01), lower LVEF (HR 0.98 (0.97-1), p = 0.015), and graft use (HR 2.29 (1.47-3.58), p = 0.001) were significant risk factors for primary patency loss. Regarding secondary patency loss, lower LVEF (HR 0.98 (0.96-1), p = 0.035) was the sole risk factor. In multivariate analysis, risk factors for cardiac events (acute coronary syndrome and aggravation of HF) in patients on dialysis were age (HR 1.06 (1.04-1.09), p = 0.001), diabetes (HR 2.46 (1.31-4.63), p = 0.005), pre-existing coronary artery disease (HR 2.84 (1.57-5.14), p = 0.001), and HF (HR 1.93 (1.05-3.56), p = 0.036). Decreased cardiac function adversely affects the primary and secondary patency of AV access, but its impact is limited. Additionally, HF is associated with future cardiac events in dialysis patients. However, HF is not independently associated with patient survival.

Streamlining Preoperative Evaluation for Dialysis Access: A Pilot Study

Outpatient in-person clinic evaluation is the standard consultation practice for an initial referral for hemodialysis (HD) access. However, most factors predicting the complexity of first-time access surgery can be determined from history rather than physical exam. This study compares the outcomes of patients undergoing first-time arteriovenous fistula creation screened with a standardized preoperative phone interview and no preoperative clinic visit (SPEEDY group) to those opting for a standard in-person clinic visit. From September 2021 to August 2022, all patients scheduled in our vascular surgery clinic for first-time dialysis access were interviewed via telephone using a standardized history questionnaire. Those meeting criteria and expressing desire to bypass the initial clinic visit were scheduled for surgery without an in-person preoperative evaluation (SPEEDY group). The comparison group included patients who were study-eligible but desired to meet with the surgeon preoperatively. Time from referral to fistula creation, overall fistula patency rates, and the incidence of access-specific complications were compared between the 2 groups. Of the 107 patients contacted, 43 (40%) were study eligible. Of these eligible patients, 21 (49%) were scheduled for surgery without a preoperative visit, of whom 19 (90%) underwent surgery. Compared to eligible controls, SPEEDY patients had a younger median age (49.3years vs. 58.9, P=0.056) but similar median duration of HD prior to fistula creation. SPEEDY patients had a significantly shorter median time from initial referral to surgery than eligible controls (48days vs. 82, P=0.01). Incidence of complications did not differ between the groups. At a median follow up time of 18.3months (IQR 11.4-20.9) there was no difference in overall access patency between SPEEDY participants and eligible controls (P=0.83). A standardized telephone questionnaire can effectively be used to identify patients who can safely undergo first time dialysis access surgery without an in-person clinic evaluation, significantly reducing time from initial referral to surgery without increasing complications or compromising patency rates.

Outcomes of Extra-Anatomic Surgical Bypass in Treatment of Central Venous Occlusive Disease in Pediatric Chronic Hemodialysis Patients: One-Year Follow-Up

Abstract Background Maintenance of hemodialysis vascular access patency in pediatric patients remains a key issue. Venous hypertension due to proximal central venous outflow obstruction is a major impediment to long-term arteriovenous access. Prior ipsilateral insertion of central venous catheters is a common risk factor. Management of Central venous occlusive disease (CVOD) in an attempt to avert sacrificing the fistula and improving symptoms of venous hypertension. Surgical bypass has the advantage of being a bale out technique for management of CVOD with maintaining the existing dialysis access and providing prolonged patency and satisfactory outcome specially with the scarce data about the role of endovascular intervention in management of CVOD in pediatric population. Objectives The aim of our prospective, observational study is to evaluate the efficacy and outcome of the surgical management of hemodialysis-related central venous occlusive disease in pediatric patients. Patients and Methods This study was conducted on (15) Pediatric patients with end stage renal disease on regular hemodialysis via upper extremity access who underwent extra-anatomic surgical bypass to treat symptomatic venous hypertension due to central venous occlusive disease. Bypass take-off was from subclavian vein, cephalic vein, or axillary vein of the affected side according to site of obstruction and outflow including contralateral subclavian vein, internal jugular vein or ipsilateral femoral vein. The study period started from June 2021 until May 2022. Patients included in the study were essentially attending the Vascular Outpatient Clinic at Ain Shams University Hospitals and Nasser Institute for Search & Treatment at Cairo. Results Regarding the type of bypass used in the studied patients, the most frequent type used is Lt Axillary to Rt Subclavian bypass and Lt Subclavian to Rt Subclavian bypass 3 (20%) followed by Rt Axillary to Lt Subclavian bypass, Rt Cephalic to Lt Subclavian bypass and Rt Axillary to Rt femoral bypass 2 (13.33%). Technical success was achieved in the 15 (100%) cases while functional success occurred in 13 (86.6%) cases; patients had performed their 4 hours hemodialysis sessions via their preexisting access within 24 h post-procedurally. No in-hospital morbidity or death was recorded. Primary patency rates at 1, 3, 6, and 12 months were 93.3, 86.6, 73.3, and 66.6%, respectively. Secondary patency rates at 1, 3, 6, and 12 months were 100, 93.3, 80, and 73.3%, respectively. Conclusion Extra-anatomic surgical bypass is safe and effective method for management of Central venous occlusive disease and has the advantage of being a bail out technique for maintaining the existing dialysis access and also providing symptomatic relief of venous hypertension, prolonged patency and satisfactory outcome.

Stent Placement After Percutaneous Recanalization of Superior Vena Cava Stenosis in Maintenance Hemodialysis Patients.

This study aimed to evaluate the efficacy and safety of stent placement after percutaneous recanalization of superior vena cava (SVC) stenosis in maintenance hemodialysis patients. Adult maintenance hemodialysis patients hospitalized at a university-affiliated tertiary hospital due to SVC stenosis from January 2016 to June 2023 were prospectively included. The efficacy and safety of percutaneous blunt/sharp SVC recanalization combined with SVC stent placement were observed. The patients' demographic information and laboratory examination data, stent placement success rate, surgery-related complications, and long-term vascular access patency rate were also recorded and analyzed. The study was approved by the institutional ethics committee (2015-201) and registered at http://www.chictr.org.cn (registry number: ChiCTR-ONN-16007790). A total of 58 patients were included in the study with an average age of 54.79±13.42 years. Percutaneous SVC recanalization was successful in 53 cases, with a success rate of 91.38%, including 37 cases of traditional recanalization and 16 cases of sharp recanalization. Among 53 hemodialysis patients who underwent SVC recanalization, 14 patients successfully received covered stents and 38 patients received bare metal stents, achieving a stent placement success rate of 98.1%. One patient encountered stent displacement into the heart immediately after implantation, causing intra-operative cardiac tamponade, who was successfully rescued by thoracotomy. Fifty-two patients were followed-up for median period of 26 months (cuffed catheter: 25 patients, arteriovenous fistula [AVF]: 27 patients). The overall 2-year vascular access patency rate was 33.2% (cuffed catheter: 22.2%, AVF: 41.7%, p=0.414). There was no statistically significant difference in the 2-year vascular access patency rate between the traditional recanalization group and the sharp recanalization group (34.1% vs 31.1%, p=0.731) and between bare metal stent group and covered stent group (38.1% vs 21.4%, p=0.248). Percutaneous SVC recanalization with stent placement is an effective treatment strategy that can provide viable vascular access for maintenance hemodialysis patients with SVC stenosis. Cautions should be paid to potential life-threatening complications such as stent displacement and cardiac tamponade. Superior vena cava (SVC) stenosis is a common central venous occlusive lesion in maintenance hemodialysis patients. Whether stent should be implanted simultaneously following SVC recanalization is still lacking research. This pilot cohort study suggested that percutaneous SVC recanalization with stent placement was an effective treatment strategy which provides satisfactory vascular access for hemodialysis. We further found that SVC sharp recanalization with subsequent stent implantation was a feasible treatment, with the 2-year vascular access patency comparable to the traditional SVC recanalization group. This study also highlighted endovascular SVC recanalization should be performed with caution, and appropriate balloon sizes should be selected to avoid SVC rupture or stent displacement.

Re-Establishment of Vascular Access After Superior Vena Cava Occlusion in Hemodialysis Patients

To evaluate the application of percutaneous right atrial puncture and tunneled cuffed catheter insertion and the establishment of peripheral arteriovenous (AV) access in hemodialysis patients with superior vena cava occlusion (SVCO), and to provide evidence-based support for the re-establishment of vascular access in patients with limited vascular resources. Patients with SVCO were enrolled. Then, either right neck percutaneous puncture catheterization or peripheral AV access construction was performed on the patients according to their personal preference. The patients were divided into the catheter group and the AV access group accordingly. Under the guidance of double C-arm digital subtraction angiography, a puncture was made in the right brachiocephalic vein or the stump of superior vena cava. Portal venous shunt instrument RUPS100 was then inserted through the guide wire, and the hard end of the guide wire was used to puncture the right atrium to achieve sharp recanalization of the occlusive superior vena cava. Afterwards, balloon expansion of the obstructive superior vena cava lesion and the subsequent implantation of the tunneled-cuffed catheter were performed. In AV access group, after evaluating the collateral veins by venougraphy and the peripheral vessel by ultrasound, autologous AV fistula or graft was established according to the vascular conditions of the patient and their personal preferences. The demographic information and clinical outcomes, such primary and primary assisted patency of access, were documented and the incidence of complications was monitored. With the duration of patent access defined as the survival time, Kaplan-Meier survival analysis was performed to compare the patency rates of the two groups. A total of 45 SVCO patients were enrolled and underwent re-establishment of vascular access. Among them, 21 cases were in the catheter group and 24 cases were in the AV access group. All patients had their vascular access successfully constructed and received hemodialysis, and no relevant complications or deaths occurred during the procedure. Over the mean follow-up period of (471.22±125.94) days, the primary patency rates in the catheter group 95.2% and 85.7% at 6 and 12 months, respectively, and the primary assisted patency rates were 100% and 95.2%, respectively. The primary patency rates of the AV access group were 79.2% and 62.5% at 6 and 12 months, and the primary assisted patency rates were 95.8% and 87.5%, respectively. No significant difference was observed between the two groups. Kaplan-Meier survival analysis showed that the median survival time (defined as the duration of patent access) was 670.00 (468.99, 871.01) days in the catheter group and 450.00 (339.24, 560.76) days in the AV access group, with the catheter group outperforming the AV access group. The primary patency rate of the catheter group was better than that of the AV access group (P=0.049). On the other hand, no significant difference was observed in the primary assisted patency rates of the two groups. Long-term vascular access can be established for SVCO patients by either percutaneous catheterization through the right atrium of superior vena cava stump or the establishment of peripheral AV access. The comprehensive plan, which includes the establishment of AV access first and the subsequent catheterization, is expected to improve the total duration of long-term vascular access and prolong the overall survival of dialysis patients, which provides new ideas for re-establishing dialysis access in patients with exhausted central venous resources.

Recurrent thrombosis and patency of the arteriovenous access in patients receiving hemodialysis.

Thrombosis of the vascular access in patients with end-stage renal disease requiring hemodialysis are common and require timely interventional procedures to restore patency. The aim of the current study was to identify factors having a significant effect on patency rates after access thrombosis. Our hypothesis was the length of time between the initial clotting of the access and the subsequent percutaneous declotting impacts the patency rates of the vascular access. In this retrospective cohort study, patients with a clotted arteriovenous access between Jan 1, 2011, and Jan 1, 2016, were included. Demographics, access history, and associated details of the access procedure were reviewed from the electronic medical record. Statistical analysis was done using t-test and chi-square or fisher exact tests to compare arteriovenous fistulae (AVF) and arteriovenous grafts (AVG). Primary patency, defined as the time from index procedure to endpoint, was analyzed using the Kaplan-Meier method and log rank test. There were 883 percutaneous declotting procedures reviewed. About 351 procedures were performed in patients with an AVF and 532 with an AVG. The mean time from thrombosis to declotting was 1.71 ± 2.29 days. The overall median primary patency for both AVF and AVG was 43 days with no difference in patency between patients with AVF (39 days) versus AVG (42 days; p = 0.385). The time period from access thrombosis to declotting did not affect patency rates for either AVG or AVF (p = 0.385). On multivariable analysis, prior intervention (HR: 1.32, 95% CI: 1.14-1.53, p < 0.001) and cardiovascular disease (HR: 1.19, 95% CI: 1.03-1.37, p = 0.016) were independently associated with access patency. Time from thrombosis to declotting did not affect patency rates however once there was a thrombotic event, recurrent thrombosis requiring intervention was common with patency significantly decreased. Future prospective studies to validate our results and study pathogenic mechanisms of recurrent thrombosis are warranted.

Percutaneous Endovascular Creation of a Neo-arteriovenous Fistula in Dysfunctional Hemodialysis Fistulas.

Arteriovenous fistulas (AVF) is the preferred type of hemodialysis access, but when an arteriovenous anastomosis (AVA) calcifies, surgical revision of the AVF may be required. We report a technique to create percutaneous artery-to-vein intervascular neo-fistulas for re-anastomosis of AVA and evaluate its safety and efficacy. 9 patients who failed either guidewire navigation or conventional balloon dilation for calcified AVA stenosis/occlusion underwent a salvage procedure of their dialysis shunt by the percutaneous creation of a new arteriovenous fistula. Needle puncture of the adjacent supplying artery and outflow vein under ultrasonographic and/or fluoroscopic guidance was performed and followed by balloon dilation, with or without stent graft placement. The detailed techniques, technical success, primary neo-fistula patency, primary and secondary access patency rates were reported herein. Technical success was achieved in 100% of the 9 patients treated (7 neo-fistulas with stents and 2 neo-fistulas without stent placement). The median primary neo-fistula and access patencies were 15 and 5months, respectively. The primary neo-fistula patency rates at 6, 12, and 18months were 72.9%, 54.7% and 27.9%, respectively, with secondary neo-fistula and access patency rates of 72.9%, 72.9% and 72.9%, respectively.One delayed complication of pseudoaneurysm formation occurred, which was managed by the successful endovascular deployment of a stent graft on an out-patient basis. Percutaneous artery-to-vein intervascular neo-fistula creation is feasible for re-anastomosing calcified AVA, with low adverse effects and acceptable primary neo-fistula and secondary access patency.

Outcomes of leadless pacemaker in chronic kidney disease patients: real-world data from the i-LEAPER registry

Abstract Background Chronic kidney disease (CKD) represents a major risk factor for patients requiring transvenous pacemaker (TV-PM), resulting in a high rate of operative complications and PM-related infection rate (21.9% and 12.5%, respectively), with both complications parallels to severity of CKD. Moreover, TV leads represent an important concern for end-stage CKD patients, often needing vascular access patency for renal replacement therapy. In this setting leadless pacemakers (LPMs) represent an attractive alternative to TV-PM for their lower device-related infection rate and the absence of TV leads. To date, limited data on LPM safety and efficacy profile in CKD patients are available. Purpose to assess operative and long-term safety and efficacy of LPMs implantation in patients with different stages of CKD in the real-world setting. Methods Consecutive patients who underwent LPM implantation in 12 European centers joining the i-LEAPER registry were retrospectively enrolled. CKD stage was assessed according to CKD-EPI equation for eGFR. Patients with CKD stage G3a/b (N=245) and stage G4/G5 (N=67) were compared with patients with normal kidney function (NKF) (N=867). Primary safety endpoint was LPM-related major complications rate at implant and during follow-up (FU). Additionally, the rate of patients showing sub-optimal electrical performance (pacing threshold [PT] &amp;gt;1V@0.24ms) was compared between groups. Results 1179 patients were enrolled and followed for a median of 33 [IQR 24-47] months. When compared with the NKF group, patients with CKD stage G3a/b and stage G4/G5 showed a higher burden of cardiovascular comorbidities (Table 1). The choice of a LPM was mainly due to vascular concern in the CKD stage G4/G5 group, while a perceived highest infective risk was reported in CKD stage G3a/b group (Table 1). Major complication rate at implant and during FU did not differ between groups, regardless of renal impairment stage (Table 2). All-cause mortality incidence resulted higher in CKD stage G4/G5 group when compared with NKF group (17.9% vs 6.8%; HR 4.24; 95%CI 4.25-7.94, p&amp;lt;0.001) (Figure A). The rate of patients with PT&amp;gt;V1@0.24ms during FU did not differ between groups, not exceeding 13.8%, and therefore remaining consistent with historical data for LPM (Figure B). Conclusion In the real-world setting, LPM showed a remarkable safety and efficacy profile in CKD patients regardless of renal impairment stage that was comparable to NKF population. LPM should be considered as first choice in CKD patients requiring a PM.

#2331 Distal arteriovenous fistulas for hemodialysis – too many interventions?

Abstract Background and Aims Distal arteriovenous fistula (dAVF) for haemodialysis (HD) is preferred due to lesser complications, despite greater risk of maturation failure. In HD patients, age and comorbid conditions increased the risk of access failure and number of procedures necessary for fistula patency. Preferred location for AVF poses a challenging decision. Advantages of dAVF must be taken into account although these may lead an unreasonably high number of interventions. Our aim was to determine time to functioning distal AFV in our centre and number of procedures necessary to achieve such status. Method Single centre retrospective analysis was performed on a cohort of patients submitted to distal AFV construction from 2015-2021. Success rate was defined as AFV patency in time for dialysis. Results Of 528 patients submitted to AVF construction from 2015 - 2021, 110 radiocephalic fistulas were seen, 59% male patients, mean age 68.5±12,0 yrs. Comorbidities were prevalent (80.9%, n=89), DM (54.6%) and HF (41.1%). Outcomes at 6 weeks were adequate maturation in 4.5% (n=59), 31.8% (n=35) late maturation (LM) and 14.5%(n=16) primary failure (PF). Causes of LM included inflow and outflow stenosis, 34.3% and 37.1%, respectively. LM (&amp;gt; 6 weeks) requiring no further intervention was seen in 28.6%. PF patients had smaller artery diameters on pre-operative US, with no statistical significance (0.23±0.07; 0.30 ± 0.2; p=0,375). Assisted patency rate was 78.2%. Number of procedures for access permeability was 1, 2 e 3 in 40%, 25.5% and 6.4%, respectively. Mean of 1,5±0,7 interventions per patient. Median time-to-adequate AFV was 2.0 (IQR 2,0 - 6,45) months. Success rate was 72,8%. Conclusion Outcomes at 6 weeks in our cohort were similar to those reported in literature. Timely referencing may increase access patency with resort to vascular intervention. Individualized management is essential, discussing risks and benefits taking into account the treatment burden associated with numerous procedures. Patency rates and outcomes after HD initiation and even cost analysis are essential to guide recommendations.

#2778 The Charlson Index can be used prospectively to identify patients who will need a close follow up of surveillance for the vascular access

Abstract Background and Aims The primary screening methods for monitoring vascular access in haemodialysis involve measuring access blood flow and dialysis venous pressure. However, challenges are present in both aspects, potentially hindering the attainment of desired results. Research in this field is crucial to identify the optimal combination of intensive clinical monitoring and supplementary surveillance for effective outcomes. For this reason, we aim to describe the impact of comorbidities and patency of native arteriovenous fistulae (nAVF). Method Descriptive study of prevalent patients on haemodialysis, carried out by consulting electronic medical records over a period of 35 months. Demographic and vascular access-related variables were included. Primary and secondary patency was calculated for all accesses. Patients with upper limb AVF were classified according to distal and proximal access location; and the Charlson Index was used to categorise patients according to comorbidities. Kaplan Meyer survival curves were used to contrast the impact of comorbidities on the different patency. Results 52 patients, age 70.7 ± 1.57 years, 69.2% male, 42.3% diabetic, Charlson index with a median of 7 (6.5 - 7.73), 98.1% with a native fistula, the most frequent nAVF location in our population was humerocephalic (63.5%) and a predominance of the left upper extremity (65.4%). According to the location of the access, adjusted by the Charlson index, it is evident that in proximal accesses (humerocephalic and basilic humerus nAVF), with a Charlson Index less than or equal to 7, the time required to reach an event was statistically significantly longer (Log Rank Test (Mantel-Cox): primary patency p=0.057 and secondary patency p=0.069). This comparison was not significant in distal fistulas. Conclusion Using the Charlson comorbidity index information, we transformed it into an accessible and valuable tool for maintaining vascular access patency. Close follow-up in patients with proximal nAVF and high Charlson comorbidity index could be beneficial.

Association between heart failure and arteriovenous access patency in patients with end-stage renal disease on hemodialysis: Presented at 2023 Vascular Annual Meeting of the Society for Vascular Surgery, National Harbor, Maryland, June 14, 2023.

Association between heart failure and arteriovenous access patency in patients with end-stage renal disease on hemodialysis: Presented at 2023 Vascular Annual Meeting of the Society for Vascular Surgery, National Harbor, Maryland, June 14, 2023.

Ruminant model for hemodialysis cannulation.

Preventative strategies that minimize hemodialysis access complications remain limited. This study aimed to address this gap by developing a Caprine cannulation model to investigate the impact of repeated cannulations on vascular access patency rates. In this pilot study, a meta-analysis was conducted using experimental control data from four trials to explore the impact of Caprine breed (independent variable) on the dependent variables that affect hemodialysis cannulation, including AVF growth, AVF depth, and flow rate. Arteriovenous Fistulas (AVFs) were created using the carotid artery and jugular vein in the necks of seven goats from the French alpine, dwarf, and pygmy breeds. All seven AVFs exhibited vessel remodeling patterns similar to that observed in humans and remained patent, enabling hemodialysis access over the 6 month study. Over the course of 18 weeks, a total of 291 cannulations were completed using standard 15 g dialysis needles without complications demonstrating the feasibility of using the Caprine species as a cannulation model. The ease of access coupled with the animals' cooperative behavior further contributes to the suitability of the Caprine species for hemodialysis investigations. Notably, no infections or clinically significant incidents were observed throughout the study. The stability of AVF patency and flow underscores the viability and potential of the Caprine species animal model as a valuable research platform for exploring interventions aimed at improving vascular access survival in hemodialysis patients.

Risk factors for repeated percutaneous transluminal angioplasty of hemodialysis vascular access after initial intervention.

Percutaneous transluminal angioplasty (PTA) is a significant intervention to deal with occlusion and stenosis of vascular access. The study aimed to explore the risk factors of repeated PTA (re-PTA) after the initial intervention in patients undergoing hemodialysis. This retrospective study included 180 patients who underwent successful PTA for the first time between March 2016 and December 2020. Information on demographic, clinical, anatomical, and medication variables was collected. Survival curves were plotted using Kaplan-Meier analysis and the risk factors associated with re-PTA were analyzed using univariate and multivariate Cox proportional hazards analyses. The primary clinical patency rates at 6, 12, and 24months after PTA were found to be 85.2%, 70.7%, and 58.6%, respectively. The univariate Cox proportion hazards analysis revealed the association of non-antiplatelet agents (HR 2.368 95% CI 1.351 to 4.150, p = .003) and arteriovenous graft (AVG) (HR 2.096 95% CI 1.147 to 3.831, p = .016) with re-PTA. However, only non-antiplatelet therapy showed statistical significance (HR 2.368 95% CI 1.351 to 4.150, p = .003) in multivariate Cox proportional hazards analysis. Among the patients undergoing hemodialysis, the use of antiplatelet agents was associated with a lower risk of re-PTA. Therefore, the use of antiplatelet drugs may reduce the rates of re-PTA and help in maintaining the patency of vascular access.

Endovascular Fistula Salvage for Preserving Arteriovenous Fistula Failure in Haemodialysis Patient: Tertiary Referral Hospital, a Single-Centre Experience

Abstract: Efficacy of endovascular intervention for the preservation of failing accesses is very important in hemodialysis patients. This study aimed to determine the efficacy of endovascular balloon angioplasty in preserving the patency of hemodialysis arteriovenous fistula (AVF) failure. This was a retrospective study of hemodialysis patients who received endovascular intervention due to access difficulties. A single-center study was created between January 2022 and June 2022. Fistulography was conducted on patients suspected of having access stenosis, and balloon angioplasty was performed in the same setting if stenosis of 50% was confirmed. Post-operative complications and access restenosis or failure were monitored. The results obtained 69 patients with hemodialysis access failure due to AVF stenosis, occlusion, and thrombosis that were admitted or referred to our hospital. The majority of patients were 40-60 years (50.7%); 88.4% patients were male and 11.6% were female, with a mean age of 56.3±11.6 (range, 18–77). The sites of AVF failure were brachiocephalic (81.1%) and radiocephalic (18.9%). There was no complication recorded. The procedure succes rate was 81.1%. In conclusion, endovascular balloon angioplasty is effective in restoring hemodialysis access patency. Recurrence is common, and interventions must be repeated. Keeping access open can save lives. Percutaneous transluminal angioplasty (PTA) can be used to achieve safely and successfully repair arteriovenous fistulas failure. Keywords: angioplasty; arteriovenous fistula; arteriovenous graft; hemodialysis

ANTIPLATELET MEDICATIONS IN HEMODIALYSIS: A SYSTEMATIC REVIEW

Background: Vascular access failure is a common complication seen among hemodialysis (HD) patients. Antiplatelet (AP) medications are often prescribed to help reduce thrombosis and increase vascular access patency. Studies on AP agents evaluating the bleeding risk for HD patients have produced inconsistent results. We aimed to investigate the utilization of AP medications among patients who undergo hemodialysis (HD). We performed a systematic review and meta-analysis of observational studies on AP medicaations used in HD therapy. Methods: This systematic review used Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 as standards. Inclusion criteria for literature eligibility are full-text literature, written in english, and published between 2014 and 2024. Exclusion criteria used for this study were editorials, review articles and identical journal that has been published, and submissions without DOI. Literatures were collected from online reference sources like Pubmed and SagePub. Result: In the PubMed database, the results of our search brought up 23 articles, whereas the results of our search on SagePub brought up 19 articles. The results of the search conducted for the last year of 2014 yielded a total 9 articles for PubMed and 5 articles for SagePub. In the end, we compiled a total of 5 papers, 4 of which came from PubMed and 1 of which came from SagePub. We included five research that met the criteria. Conclusion: AP medications are given in HD patients with high cardiovascular commorbidities to increase vascular patency and prevent thrombosis. Aspirin and P2Y12 inhibitors (PI) such as clopidogrel are commonly used. AP medications might cause shortened longevity of AV access for HD patients. The benefits of AP therapy for cardiovascular protection needs to be evaluated along with its possible effect on AVG outcomes.

Perioperative Vascular Access Mapping in Patients with Hemodialysis: A Comparative Study of Access Navigation and Selection in Jordan.

This study aimed to elucidate the impact of three different mapping methods on the outcomes of arteriovenous fistula (AVF), including the traditional physical examination (PE) method, color duplex ultrasonography (CDU) mapping conducted by a radiologist (CDU-R), and CDU mapping performed by the operating surgeon (CDU-S). This retrospective study was conducted at a tertiary center in Jordan. Patients were divided into three groups based on the venous mapping method: PE, CDU-R, and CDU-S. Various outcomes were analyzed, including immediate technical success, clinical adequacy at 3 months, and 1-year patency rates. Additional demographic and clinical factors influencing access patency or contributing to early failure were also examined. The study included 303 eligible patients: 100 in the PE group, 103 in the CDU-R group, and 100 in the CDU-S group. The overall immediate technical success rate was 72%, which was highest in the CDU-S group (95%, p < 0.001). Additionally, the CDU-S group had the highest clinical access adequacy rate (78%, p < 0.01). Notably, the mapping method also influenced the anatomical location of the AVF, as none of the patients in the radiologist group had a forearm AVF. CDU-R, forearm location, intraoperative arterial calcifications, and operative duration were identified as predictors of AVF failure. The results suggest that perioperative vascular mapping by the operating surgeon not only results in a higher rate of immediate success but also improves access adequacy and prevents unnecessary delays in providing an effective lifeline for hemodialysis patients. The present study highlights the burden of access failure in these patients and the evolving evidence surrounding preoperative vein mapping.

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction.

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

Association between heart failure and arteriovenous access patency in patients with end-stage renal disease on hemodialysis

BackgroundHeart disease and chronic kidney disease are often comorbid conditions owing to shared risk factors, including diabetes and hypertension. However, the effect of congestive heart failure (CHF) on arteriovenous fistula (AVF) and AV graft (AVG) patency rates is poorly understood. We hypothesize preexisting HF may diminish blood flow to the developing AVF and worsen patency. MethodsWe conducted a single-institution retrospective review of 412 patients with end-stage renal disease who underwent hemodialysis access creation from 2015 to 2021. Patients were stratified based on presence of preexisting CHF, defined as clinical symptoms plus evidence of reduced left ventricular ejection fraction (EF) (<50%) or diastolic dysfunction on preoperative echocardiography. Baseline demographics, preoperative measures of cardiac function, and dialysis access-related surgical history were collected. Kaplan-Meier time-to-event analyses were performed for primary patency, primary-assisted patency, and secondary patency using standard definitions for patency from the literature. We assessed differences in patency for patients with CHF vs patients without CHF, patients with a reduced vs a normal EF, and AVG vs AVF in patients with CHF. ResultsWe included 204 patients (50%) with preexisting CHF with confirmatory echocardiography. Patients with CHF were more likely to be male and have comorbidities including, diabetes, chronic obstructive pulmonary disease, hypertension, and a history of cerebrovascular accident. The groups were not significantly different in terms of prior fistula history (P = .99), body mass index (P = .74), or type of hemodialysis access created (P = .54). There was no statistically significant difference in primary patency, primary-assisted patency, or secondary patency over time in the CHF vs non-CHF group (log-rank P > .05 for all three patency measures). When stratified by preoperative left ventricular EF, patients with an EF of <50% had lower primary (38% vs 51% at 1 year), primary-assisted (76% vs 82% at 1 year), and secondary patency (86% vs 93% at 1 year) rates than those with a normal EF. Difference reached significance for secondary patency only (log-rank P = .029). AVG patency was compared against AVF patency within the CHF subgroup, with significantly lower primary-assisted (39% vs 87% at 1 year) and secondary (62% vs 95%) patency rates for AVG (P < .0001 for both). ConclusionsIn this 7-year experience of hemodialysis access creation, reduced EF is associated with lower secondary patency. Preoperative CHF (including HF with reduced EF and HF with preserved EF together) is not associated with significant differences in overall hemodialysis access patency rates over time, but patients with CHF who receive AVG have markedly worse patency than those who receive AVF. For patients with end-stage renal disease and CHF, the risks and benefits must be carefully weighed, particularly for those with low EF or lack of a suitable vein for fistula creation.

How do Different Types of River Maintenance Works Affect the Ichthyofauna of Small European Watercourses?

Abstract Watercourses serve the needs of agriculture in certain sections and are subject to strong anthropopressure. When agriculture prevails in the catchment, it often has abundant vegetation, macrophytes in particular, and the bottom is covered by a substantial layer of silt. In order to ensure patency of flow and access to water, small watercourses are very often subject to river maintenance works. The aim of the study was to assess the impact of 3 types of works on the diversity of fish species and density of fish in the 1 and 2 year after the works at 21 sites located on 8 rivers in the European Central Plains Ecoregion. As a result of the works, especially in the 1 year after the works, significant changes were found in hydrochemical and hydrological parameters, especially with the increase in velocity and mean depth in watercourses. Additionally, habitat change contributed to differences in the composition of the ichthyofaunal. After 1 year, the diversity of fish species and fish population density increased or remained unchanged after dredging and removal of plants from the river channel, but they decreased after the removal of macrophytes from river banks. After year 2, a decrease in the diversity of fish species and density was observed, associated with re-infestation and siltation of the watercourses. Particularly in the case of dredging and removal of macrophytes from the river bank, maintenance works should not be done too frequently, because some species of natural value disappear.