Hemodialysis Vascular Access Research Articles

New Frontiers in Vascular Access Practice: From Standardized to Patient-tailored Care and Shared Decision Making.

Vascular access planning is critical in the management of patients with advanced kidney disease who elect for hemodialysis for RRT. Policies put in place more than two decades ago attempted to standardize vascular access care around the model of optimal, namely arteriovenous fistula, and least preferred, namely central venous catheter, type of access. This homogenized approach to vascular access care emerged ineffective in the increasingly heterogeneous and complex dialysis population. The most recent vascular access guidelines acknowledge the limitations of standardized care and encourage tailoring vascular access care on the basis of patient and disease characteristics. In this article, we discuss available literature in support of patient-tailored access care on the basis of differences in vascular access outcomes by biologic and social factors-age, sex, and race. Further, we draw attention to the overlooked dimension of patient-reported preferences and shared decision making in the practice of vascular access planning. We discuss milestones to overcome as requisite steps to implement effective shared decision making in vascular access care. Finally, we take into consideration local practice cofactors as major players in vascular access fate. We conclude that a personalized approach to hemodialysis vascular access will require dynamic care specifically relevant to the individual on the basis of biologic factors, fluctuating clinical needs, values, and preferences.

Factors Affecting the Long Term Patency of Arteriovenous Access for Hemodialysis

Objective: The objective of the study was to analyze and evaluate the possible factors in the long-term patency of arteriovenous (AV) access for hemodialysis (HD). Materials and Methods: This was a cross-sectional study recruiting patients from January 2019 to December 2019. All patients who have a working HD vascular access, either AV fistula (AVF) or AV graft which has been working for at least 2 years were included and collected demographic data along with other parameters such as timing of creation, interventions, dialysis sessions, and antiplatelet therapy among others. Results: We included 81 patients with AV access patent more than 2 years; 22.5% were aged >65 years, 39.6% were diabetic, 68.5% were hypertensive, and 26.1% had vascular disease. Analysis revealed that the patient factors such as current tobacco usage and side of creation and technical factors such as maturation time, number of dialysis sessions, and single-center dialysis have a significant effect on the patency of the AV access, while the factors such as past tobacco usage, diabetes, hypertension, use of jugular catheter before access creation, and cannulation technique could not establish any statistical effect on the patency of AV access. Conclusion: There is a complex interaction of factors that may affect the patency of an individual AV access. These need to be carefully considered when selecting surgical site or technique, adjuvant treatments, and follow-up protocols for AVFs.

Sex Differences in Inflammation During Venous Remodeling of Arteriovenous Fistulae.

Vascular disorders frequently have differing clinical presentations among women and men. Sex differences exist in vascular access for hemodialysis; women have reduced rates of arteriovenous fistula (AVF) maturation as well as fistula utilization compared with men. Inflammation is increasingly implicated in both clinical studies and animal models as a potent mechanism driving AVF maturation, especially in vessel dilation and wall thickening, that allows venous remodeling to the fistula environment to support hemodialysis. Sex differences have long been recognized in arterial remodeling and diseases, with men having increased cardiovascular events compared with pre-menopausal women. Many of these arterial diseases are driven by inflammation that is similar to the inflammation during AVF maturation. Improved understanding of sex differences in inflammation during vascular remodeling may suggest sex-specific vascular therapies to improve AVF success.

Surgical role in the management of peritoneal dialysis catheters – evidence and proposals to improve current practices

Peritoneal dialysis (PD) relies on adequate function of PD catheter. Mechanical complications are a major cause of dropout among PD patients. A prompt timing and an appropriate intervention may overcome these problems with catheter salvage, without interrupting PD treatment. Many Portuguese centers still lack a proper articulation between nephrology and surgical departments. We describe current available surgical approaches in the implantation of PD catheters, management of mechanical complications, exit -site infections and other abdominal surgical procedures. Our aim is to reinforce the need for an established protocol of action between these departments as occurs with vascular access in hemodialysis.

Ultrasound assisted catheterization of internal jugular vein

An appropriate vascular access is always needed for the success of hemodialysis. Internal jugular vein is the safest and less complicated access in between central veins. At the same time, it is the most commonly used temporary vascular access for hemodialysis. The blind method after anatomical marking for the central vascular path is the most used technique in many centers. The use of ultrasound in the placement of hemodi-alysis catheters in the central vein increases the success rate of catheterization. Ultrasound can show IJV locali-zation, anatomical variations, the presence of thrombus in the vein, and whether the vein is open. The aim of this study is to compare the success rate and complication frequency of temporary catheters placed in the IJV with and without ultrasound for hemodialysis. A total of 124 consecutive patients who required hemodialysis catheters in Haydarpaşa Numune Trai-ning and Research Hospital between February 2012 and December 2012 were randomized to the study. The patients were divided into two groups as non USG-assisted (blindly) (Group 1) and ultrasound-assisted (Group 2). The use of ultrasound significantly increased the successful catheterization rates of both experienced specialist and resident. In addition, there was no statistical difference between the success rates between the specialist and the resident. USG-assisted vein catheterization can be performed safely, easily, quickly, more painlessly and with minimal complication rates. Catheter intervention should be performed under the guidance of USG in risky patient groups who need temporary catheters. In centers that do not have USG, especially in such risky patients, blind catheter interven-tion should not be attempted after anatomical marking. USG-assisted vein catheterization can be easily perfor-med by all clinicians and residents, since the training period is short, practical and much more safe.

Stretching the boundaries: suitability of an arteriovenous fistula in elderly patients on hemodialysis-a northern India experience.

Considering various factors, such as multiple co-morbidities, unsuitable vessels for access creation, non-maturation, vascular calcifications, the outcome of arteriovenous fistula (AVF) in the elderly population, may not be similar to the younger people. Our study aims to analyze the outcomes of AVF in elderly patients (> 65year). It was a prospective observational study. Patients of more than 65years of age in whom AVF was created from January 2012 to December 2015 were included in the study. These patients were followed up for 4years. The primary endpoint of our study was to assess primary and secondary patency rates. A total of 450AVFs were included in the study. The mean age was 68.5years. The most common site of AVF was radiocephalic (RCAVF) in 70% (n = 315), brachiocephalic (BCAVF) in 24% (n = 108) and basilic vein transposition (BVT) in 6% (n = 27). At 48months, the primary patency rate of RCAVF, BCAVF, and BVT was 55%, 61.6%, and 60.4%, respectively. The commonest cause of access failure was thrombosis followed by non-maturation. AVF remains the preferred vascular access for hemodialysis even in the elderly population. Failure to mature and thrombosis continue to be a concern with AVF. Location of the AV access does not seem to impact the long-term patency.

Case report on the management of failed tunneled hemodialysis catheter insertion

Hemodialysis vascular access is critical to ensuring adequate hemodialysis sessions. Tunneled internal jugular vascular (IJV) access is a type of intermediate access that has become increasingly useful in low- and middle-income countries, where there are not many vascular surgeons with expertise in arteriovenous fistula creation. We presented a 69-year-old male who had complicated IJV catheter insertion, with the catheter located in the pulmonary vascular bed of the left lung and associated left-sided hemothorax. He was managed by multidisciplinary team of nephrologists, radiologists, and cardiothoracic surgeons, who removed the catheter under fluoroscopic guidance without any complication or need for open thoracotomy. The case highlighted the utility of fluoroscopy in aiding hemodialysis catheter insertion, removal, and management of its complications.

Prevalence and risk factors for vascular access infection among chronic hemodialysis patients in Al-Gharbia Governerate, Egypt

Background Chronic hemodialysis patients are at considerably high risk for vascular access-related blood stream infections that may be associated with serious complications. Infections are more frequent with central venous catheters and polytetrafluoroethylene grafts than with arteriovenous fistula. Aim We aim to evaluate the prevalence of vascular access infection among hemodialysis patients, risk factors, common causative microorganisms and their antibiotics sensitivity. Patients and method This cross-sectional study included 720 end-stage renal disease patients on hemodialysis recruited from six hemodialysis centers in Al-Gharbia Governorate from June 2019 to June 2020. Results The prevalence of vascular access infection was 27.77%. Sex, old age, and diabetes mellitus had a significant statistical association. Temporary catheters recorded the highest infection rate. Gram-positive bacteria were the most common organisms in 57.5% of cases, Gram negative in 39.5% while candida albicans in only 3% of the cases. The antibiotic sensitivity was higher to amikacin and imipenem. Conclusion Creation of native arteriovenous fistula is highly recommended to avoid catheter-related blood stream infections and their complications. Strict adherence to antiseptic measures and use of a rational antibiotic policy for the early diagnosis and better management of hemodialysis vascular access site infection is important.

The development of the Western Australian Haemodialysis Vascular Access Complexity instrument.

BackgroundThe Western Australian Haemodialysis Vascular Access Classification instrument was developed to classify the cannulation complexity of the arteriovenous fistula or arteriovenous graft as simple, challenging, or complex. Although the instrument was developed by experts in haemodialysis nursing, the instrument had not undergone formal validity or reliability testing.ObjectivesEvaluate the Western Australian Haemodialysis Vascular Access Classification instrument for content validity, interrater and test–retest reliability.DesignProspective cohort study.ParticipantsContent validity was assessed by haemodialysis nursing experts (n = 8). The reliability testing occurred in one in‐centre and one satellite haemodialysis unit in Western Australia from September to November 2019. Reliability testing was performed by 38 haemodialysis nurses in 67 patients receiving haemodialysis and 247 episodes of cannulation.MeasurementsInterrater and test–retest reliability assessment was conducted using κ, adjusted κ, Bland–Altman plots, intraclass correlation coefficient and Pearson's correlation coefficient.ResultsThe final version of the instrument (n = 20 items) had individual item‐level content validity indices ranging from 0.625 to 1.00 with a scale‐level content validity index of 0.89. For both interrater (n = 172 pairs) and test–retest (n = 101 pairs), most individual variables had excellent adjusted κ (n = 33 variables), some fair to good agreement (n = 6 variables) and one variable with poor agreement. The classification of simple, challenging and complex demonstrated adjusted κ of fair to good, to excellent agreement for interrater reliability with lower levels of agreement for test–retest reliability.ConclusionsThis instrument may be used to match a competency‐assessed nurse to perform the cannulation thereby minimising the risk of missed cannulation and trauma.

Arteriovenous shunt as the best hemodialysis access in Chronic Kidney Disease (CKD) patients: a literature review

Arteriovenous Shunt (AV Shunt) is a minor surgical operation that connects (creating anastomoses) the arteries and veins in the arm or other body part for the purpose of making connection access for hemodialysis. AV shunt is the primary choice in establishing vascular access for hemodialysis in patients with Chronic Kidney Disease (CKD). Therefore, this study aims to review the arteriovenous shunt as a hemodialysis access option in CKD patients. The literature study was conducted by searching various written sources, whether in the form of books, archives, articles and journals, or documents relevant to the problem being studied. The mortality rate after AV shunt is 0%, even though it still has postoperative complications. Based on the location of the operation, making the AV shunt is prioritized on the distal part that is not dominant to minimize the damage to the AV shunt. The location of the wrist, namely the brachiocephalic, is a top priority in making an AV shunt because it has many advantages. AV shunt is the primary choice of vascular access for hemodialysis in patients with chronic kidney disease. It is hoped that through the AV shunt, the life expectancy of patients with CKD can be increased, and patients with CKD must receive support from other disciplines such as interns, psychologists, and the patient's family.

Acute hepatitis post arteriovenous graft thrombectomy of hemodialysis vascular access.

The following paper reports the case of a woman on in-center hemodialysis through an arteriovenous graft, who attended with an acute vascular access thrombosis. Post percutaneous thrombectomy, the patient presented a rare case of self-limited acute hepatitis secondary to the revascularization procedure. We explain the probable trigger for this complication, its pathophysiology, management, and evolution.

Outcomes and predictors of failure of arteriovenous fistulae for hemodialysis

PurposeArteriovenous fistula(AVF) is preferred vascular access for hemodialysis but has primary failure in 20–60%. Studying predictors of AVF failure would help plan appropriate management.We studied AVF outcomes, clinical and vascular factors predicting their failure in patients requiring hemodialysis.MethodsRetrospective study of patients with AVF creation from January 2017 to December 2018. Outcomes studied were immediate (< 72 h), primary (3 months) AVF failure, six-month/one-year patency, analyzed for predictive clinical, vascular factors as assessed using Pre-operative Doppler Ultrasound(DUS).ResultsOf 530 AVFs in 460 patients, DUS was done in 426/530 (80.4%), 349/460 (75.8%) were males, mean age was 53.10 ± 14.54 (18–91), 215/460(46.7%) had Diabetes mellitus(DM), 423/460(92%) hypertension. AVFs were radiocephalic in 79/530 (14.9%), brachiocephalic 418/530 (78.9%), brachiobasilic 33/530 (6.2%). AVF Immediate/Primary failure was seen in 64/530 (12.1%), 90/352 (25.6%); Patency at six months/one year in 253/352(71.8%),191/305 (62.6%), respectively. Older age had less immediate failures (AOR 0.97, CI 0.95–0.99, p 0.03). Feeding arterial diameter predicted immediate and primary failure on univariate analysis [OR 0.64 (95% CI 0.49–0.83), 0.62 (95% CI 0.47–0.89), respectively], but not multivariate. Artery diameter of > 4.0 mm had less failures [immediate (p 0.01), primary (p 0.02)], < 2.0 mm had specificity 95.9% and 95.4% for immediate, primary failure respectively.ConclusionAVF failure is 12.1%, immediately; 25.6% three months after construction, Patency at 6 months is 71.8%, one year 62.6%. Immediate failures decrease with age. Artery diameters > 4.0 mm had less, < 2.0 mm had more failures.

Protective Effect of Autologous Arteriovenous Fistulae Against Oxidative Stress in Hemodialyzed Patients.

Introduction: Oxidative stress (OS) is ubiquitous in chronic kidney disease (CKD) and is exacerbated by hemodialysis (HD). OS is also associated with anemia, malnutrition, and cardiovascular (CV) disease and is an independent predictor of mortality and morbidity in patients undergoing HD. HD vascular access (VA) types are strongly correlated with CKD patient outcomes. Prolonged use of central venous catheters (CVC) for HD and arteriovenous grafts (AVG) promotes inflammation and OS. However, the effects of the VA type on OS have been poorly studied in HD patients. This study investigated OS prevalence in an HD population to determine the relationship between the VA type and HD.Methods: The oxidative stress index (OSI) was used to assess the HD patients’ OS status. OSI summarizes information derived from the reactive oxygen metabolites (d-ROMs) fast test and the plasma antioxidant test (PAT) in a single value, using the hydrogen peroxide concentration (for d-ROMs) and ascorbic acid (for PAT) as reference standards. The OSI was created to indicate how far the OS status deviates from normal (i.e., fully compensated oxidative balance). An index increase may be from an increase or decrease in peroxide or antioxidant concentrations. Patients undergoing chronic HD were evaluated by dividing the cases according to the OSI status: normal (N-OSI), borderline (BL-OSI), high (H-OSI), and very high (VH-OSI). Patients with clinical evidence of active infections were excluded.Results: In total, 129 patients were included; 86.8% used high-flux dialyzers, 13.2% used hemodiafiltration (HDF), and 24.5% were diabetic. An altered OSI was observed in 86 of 129 patients (66.7%). An increased OSI correlated with a significant increase in d-ROMs (r = 0.420) and PAT (r = 0.710). There were no differences between sex, diabetes status, age, dialysis vintage, or dialysis modalities. d-ROMs were inversely correlated with hemoglobin levels (r = −0.209). The iron dose by month correlated with the OSI (r = 0.189) and was significantly lower in the N-OSI group. N- and BL-OSI patients had a significantly higher rate of autologous arteriovenous fistula (AVF) compared to the other groups, and VH-OSI patients had a higher rate of permanent tunneled CVC.Conclusion: Most HD patients had more OS, indicated by the OSI scores. In chronic HD patients, AVF had a protective effect against imbalanced peroxidation-antioxidation.

Patency and Efficacy of Anatomical Snuffbox Arteriovenous Fistula Compared with Wrist Fistula in Patients with End-Stage Renal Disease

Highlights Abstract Introduction: Snuffbox arteriovenous fistula (AVF) is one of the most common vascular accesses for hemodialysis. Despite all the advantages, it is not usually considered the first choice of treatment. This could be primarily due to difficulty in its technical procedure and a higher probability of failure than other sites such as cubital. Therefore, the present study aimed at comparing the efficacy and patency rate between the snuffbox and the wrist AVF. Methods: Seventy-eight patients with end-stage renal disease were enrolled in this study. They were randomly assigned into the snuffbox and the wrist groups. Each participant had an appropriate vein at the time of examination and was eligible for distal AVF creation. The procedure was conducted under local anesthesia, and arteriovenous anastomosis was done in an end-to-side configuration. AVF maturation was defined by initiation of successful dialysis through the AVF 8–10 weeks postoperatively. Results: The results showed that 61% of snuffbox AVFs and 65% of wrist AVFs became matured and were used for further dialysis. Diabetes and female sex had negative impacts on AVF patency. In addition, no significant relationship was found between the patency rate and demographic as well as clinical variables such as age, hypertension, and duration of the previous dialysis. Conclusions: No significant differences were found in the maturation and patency rate between the wrist and the snuffbox AVFs. Therefore, the snuffbox fistula is recommended in the first step, as there would be a possibility for re-creation on the ipsilateral wrist once the AVF fails.

MO960RENAL TRANSPLANTATION FROM A LIVING DONOR WITH RENAL ARTERY FIBROMUSCULAR DYSPLASIA

Abstract Background and Aims Renal transplantation is considered the most effective and less costly modality of renal replacement therapy in patients with end stage renal disease. The disparity between kidney allografts and recipients has led to a global effort to increase the pool of kidney donors. Accordingly, fibromuscular dysplasia (FMD) is no longer considered an absolute contraindication for kidney donation. The incidence of FMD is about 2.3%-5.8% in potential kidney donors. There are few cases in the literature where renal artery stenosis in allografts with known pre-transplantation FMD became worse after transplantation, indicating the importance of a proper follow up in the recipients. This is a case of a living kidney donor with no history of hypertension, proteinuria or elevated serum creatinine, whose intra-arterial digital subtraction angiography revealed FMD lesions in the left renal artery. Method Case report Results A 54-year-old Caucasian female with medical history of hypothyroidism took the decision to offer her kidney to her 37-year-old son who was diagnosed with end-stage renal disease five years ago secondary to diabetes mellitus type I. She had no history for diabetes, hypertension and renal disease. Her vital signs on admission were heart rate of 78 beats/min and blood pressure of 130/70 mmHg. Urinalysis, biochemical profile and serological evaluations were all within normal ranges. Blood urea was 36 mg/dL and serum creatinine was 0.6 mg/dL (eGFR 97ml/min/1.73m2). The abdominal ultrasound and renogram with Tc-99m DTPA showed no remarkable findings. On intra-arterial digital subtraction angiography an abnormal succession of dilatations and multifocal stenoses of the left renal artery, characteristic of medial FMD, was found. The right renal artery was normal. Apart from a dysfunctional permanent left femoral catheter, the patient had no other vascular access for hemodialysis because of Superior Vena Cava syndrome, so he needed urgent transplantation. Taking all of these into consideration, the patient was offered renal transplantation as the best option. A left open donor nephrectomy was performed; the renal artery was divided distal to the stenotic dysplastic area. The allograft was placed at the right iliac fossa of the recipient with arterial and venous anastomosis to the extrarenal iliac vessels. Post-operatively, the recipient had a delayed graft function lasted 13 days. On renal artery Doppler in the allograft we found increased resistance index (RI) that gradually normalized without any intervention. An immunosuppressive regiment of tacrolimus, mycophenolate and prednisone was administered according to our center protocol. At discharge serum creatinine was 1.7 mg/dL (eGFR: 50ml/min/1.73m2). At the year follow-up, the donor was normotensive and had near normal renal function (Cr:1.3mg/dL, eGFR: 70ml/min/1.73m2). The recipient has a well-controlled blood pressure receiving two antihypertensive drugs and maintains a satisfactory renal function. Conclusion Few cases with FMD in renal allografts from living and deceased donors have been described. In a review of 4 studies the authors concluded that the outcome of transplantation with allografts from living donors with medial FMD was satisfactory and these allografts could be used to increase the donor pool. Furthermore, it is strongly recommended to have a thorough pre-transplantation check of the donor as well as a close monitoring of both the donor and recipient after transplantation. This case shows that allografts harvested from carefully selected donors with renal arterial FMD can be successfully used, particularly in urgent conditions. Detailed pre-tranplantation imaging of donor’s renal arteries, selection of the appropriate screening method, as well as close monitoring of both donor and recipient for early interventions after transplantation is of paramount importance.

MO780SURVIVAL STUDY OF ARTERIOVENOUS FISTULAS CREATED IN A HIGH RESOLUTION HOSPITAL

Abstract Background and Aims Clinical practice guidelines recommend an arteriovenous fistula (AVF) as the ideal vascular access for hemodialysis. Autologous AVFs have higher primary, assisted primary and overall survival, associated with lower morbidity and mortality compared to prosthetic AVFs. However, primary failure of AVFs function is not uncommon, above all due to the vascular pathology of patients on hemodialysis (HD). We determined the survival rates in a series of vascular accesses created in a high-resolution hospital. Method Cross-sectional study; We include all AVFs performed during the last 20 years. Demographic variables (age, sex), etiology of CKD and associated comorbidity were collected. We determine the primary, assisted and global survival times. Statistical analysis with SPSS 25.0. Categorical variables are expressed as percentages and are compared using the Chi2 test. Quantitative variables are expressed as mean ± standard deviation and the Mann Whitney Student-T/U was used to compare them. We performed a kaplan-Meier analysis determining primary, assisted and overall survival. Statistical significance for a value of p &amp;lt;0.05. Results 622 AVFs performed in 482 patients were reviewed. 86.8% were autologous. The mean age was 65.4±14 years; 66.6% were male. The most frequent etiologies of CKD were diabetic nephropathy (30.2%), unknown (18%), and glomerulonephritis (16.6%). 91.2% had arterial hypertension (HBP) and diabetes mellitus (DM) 47.9%. 48.7% received antiplatelet therapy and 15.6% anticoagulation prior to the creation of the AVF. 27% presented primary failure. In the survival analysis using the Kaplan Meier test, the mean time to perform angioplasty in dysfunctional AVFs was 14.6±1.37 months and to perform a thrombectomy 17.6±1.31 months. The overall survival of AVFs was 41.9±2 months. When assessing the type of AVF, we observed a longer survival for autologous (31.5±1.8) vs prosthetic (21.8±3.6) (p = 0.03 log Rank 4.73). Conclusion In our study, autologous AVFs have better survival compared to prosthetic ones. Of the AVFs created, primary survival at one year (requiring angioplasty) was 64%, assisted primary survival (requiring thrombectomy) was 42%, and overall survival 24%.

MO775CONTROL OF BONE DISEASE ASSOCIATED WITH CHRONIC KIDNEY DISEASE AS A PREDICTOR OF PRIMARY PERMEABILITY AFTER THE CREATION OF THE VASCULAR ACCESS

Abstract Background and Aims Clinical practice guidelines recommend an arteriovenous fistula (AVF) as the preferred vascular access for hemodialysis. Patency of the arteriovenous access is important for effective hemodialysis. However, maintaining the patency of the AVF remains a challenge. We determined those independent prognostic factors for the patency of the AVF at the time of its creation. Method Cross-sectional study; We include all AVFs performed at the HGUCR in the last 2 decades. Demographic variables (age, sex), etiology of CKD and associated comorbidity were collected. We determine the factors involved in the primary patency of AVFs. Statistical analysis with SPSS 25.0. Categorical variables are expressed as percentages and are compared using the Chi2 test. Quantitative variables are expressed as mean ± standard deviation and the Mann Whitney Student-T/U was used to compare them. Statistical significance for a value of p &amp;lt;0.05. Results 622 AVFs performed in 482 patients were reviewed. 86.8% were autologous. The mean age was 65.4±14 years; 66.6% were male. The most frequent etiologies of CKD were diabetic nephropathy (30.2%), unknown (18%), and glomerulonephritis (16.6%). 91.2% had arterial hypertension (HBP) and diabetes mellitus (DM) 47.9%. 48.7% received antiplatelet therapy and 15.6% anticoagulation prior to the creation of the AVF. 27% presented primary failure. The univariate analysis showed statistical significance for the qualitative variables HTA (p=0.002), treatment with statins (p&amp;lt;0.01) and antiplatelet (p&amp;lt;0.01), and for the quantitative variables fibrinogen (p=0.048), serum phosphorus (p=0.001), CRP (p=0.004), triglycerides (p=0.05), ferritin (p=0.006) and age (p=0.05). When performing a multivariate analysis using logistic regression, HTA (OR: 0.46 95% CI 0.22-0.95 p = 0.036), high phosphorus levels (OR: 1.22 95% CI 1.08-1, 49 p = 0.004) and statin treatment (OR: 0.58 95% CI 0.36-0.96 p = 0.004) are predictors of primary VA failure. Conclusion In our study, HTA and antiplatelet therapy prior to the creation of the VA behave as protective factors for primary failure, with high phosphorus levels being an independent factor for primary failure of AVFs.

MO783CENTRAL VEIN STENOSIS IN HEMODIALYSIS PATIENTS WITH PAST CENTRAL VEIN MANIPULATION

Abstract Background and Aims Central vein stenosis (CVS) is frequently observed in hemodialysis patients. Risk factors for CVS include prior ipsilateral central venous catheterization (CVC) and cardiac rhythm device (CRD) insertions. Though it may have clinical manifestations, CVS is often asymptomatic and, therefore, not diagnosed. The aim of this work was to evaluate the prevalence of CVS in a population of hemodialysis patients, as well as underlying risk factors, clinical manifestations and impact in patients’ vascular access. Method We retrospectively evaluated all venous angiographies of prevalent patients in our hemodialysis units from 2013 to 2018. In patients with proved CVS, we evaluated history of prior short term and long term upper ipsilateral CVC and CRD insertions. We also analyzed symptoms associated CVS as well as the rate of loss of vascular access for hemodialysis related to the presence of CVS. Results The prevalence of CVS in prevalent patients in hemodialysis during the period of our study (n=209) was 14%. We identified 31 upper CVS in 29 patients undergoing venous angiography. Left brachiocephalic vein was the most commonly affected site (45.1% of cases), followed by the right brachiocephalic vein (19.3%), left subclavian vein (16.1%), right subclavian vein (12.9%) and superior vena cava (6.4%). The majority of patients with CVS (95%) had previous history of ipsilateral CVC (previous short-term CVC in 40%, pervious short term and long-term CVC in 27% and previous long-term CVC in 33%). Loss of vascular access for hemodialysis due do CVS was observed in 26% of patients with CVS. Conclusion A significant proportion of patients in hemodialysis presents CVS. The majority of patients with CVS had a previous history of ipsilateral central venous catherization. A significant proportion of patients with CVS had a previous history central venous catherization uniquely with short term CVC, highlighting the importance of the risk of vascular lesion, even during short periods of catherization. The presence of CVS is associated with a significant rate of loss hemodialysis vascular access.

MO766EARLY ARTERIOVENOUS FISTULA FAILURE PREDICTION WITH ARTIFICIAL INTELLIGENCE: A NEW APPROACH WITH CHALLENGING RESULTS

Abstract Background and Aims The native arteriovenous fistula is considered the vascular access of preference, since it is directly related to major survival, reduced complications, mortality, and costs. Still, its proper maintenance remains a challenge for nephrologists. A previous study from our group, which used the data of 117 arteriovenous fistulas, led to identify in the multivariable analysis age and vein diameters as predictive factors for early failure. On the other hand, Artificial Intelligence has been established as a tool to identify relationships between variables at deep levels, which might be unseen with more conservative methods like classic statistics. Therefore, through a Machine Learning technique known as Random Forest, the aim is to evaluate the same comorbidity, biological and Doppler ultrasound variables data to identify those with a major relation with the early failure of the native arteriovenous fistula. Method Retrospective cohort study, gathering the same data of the previous study (from 2011 to 2015): survival, ultrasound mapping (morphology and hemodynamics), comorbidities (blood pressure, severe arteriopathy, diabetes, Charlson’s Index), and laboratory (haemoglobin, calcium, phosphorus, PTH, ferritin, PCR). Different Artificial Intelligence algorithms were tested, but the most suited one for the study's aim turned out to be Random Forest. A model was trained, dividing the data in two sets, training and validation, with an 80/20 ratio. The algorithm used 100 decision trees, with a maximum individual depth of 3 levels. The training was made with the variables that represented the 100%, 95%, 90% and 85% of impact in the fistula's maturation from a theresold according to Gini’s Index. Results Age 65.7 (32-88) years, male 59.8%. Hypertension 86.7%, diabetes 50.7% and vascular disease 41.3%. The trained model obtained provided the following results in the evaluation: accuracy 0.82, precision 0.86, AUROC 0.85, F1 0.86 (balance between precision and predictive value). The most relevant variables by decision order were age, phosphorous, PTH, ferritin and calcium. Morphologic and hemodynamic variables such as the vessels diameter, Peak Systolic Velocity, Charlson’s Index or PCR, were also found to be relevant, but in a minor level. Conclusion In comparison with classic statistics, Machine Learning techniques might create a change of paradigm in predictive models for the patency of the vascular access for Haemodialysis. Even though the Artificial Intelligence-based model provided the same relevance for age in maturation failure as traditional models, other findings stand out, like the major participation of variables related with mineral metabolism or inflammation, rather than ultrasound based ones.

MO1022CENTRAL VENOUS CATHETERS FIRST - THE ACHILLES’ HEEL IN PEDIATRIC HEMODIALYSIS VASCULAR ACCESS

Abstract Background and Aims Management of children with end-stage kidney disease (ESKD) requiring dialysis is always challenging and particular concerns exists regarding vascular access. International reports through the years are not satisfactory, with a high rate of central venous catheter (CVC), when “Fistula First” is the goal in Hemodialysis (HD). Suggested reasons for this phenomenon include, for example, age-related anatomical limitations, shorter awaiting times for or “scheduled” transplantation, pain and anxiety related to punctures or lack of pediatric/surgical expertise. Here we present the results of the last 13 years of experience in pediatric HD vascular access from a reference center in northern Portugal. Method A retrospective descriptive study of patients admitted to our pediatric HD Unit between January 2007 and December 2020. Clinical data was collected from medical records. Results 40 patients were enrolled, mainly boys (n=22, 55%), mean age at admission 10.9±5.3 years (1-17 years), 63% weighing more than 30 kg (n =25) and 15% less than 15kg (n=6). More than half were incident patients starting on HD (n=22, 55%), 42.5% were transferred from peritoneal dialysis (PD) and one patient had a previous kidney transplant (KT). Regarding CKD etiology, 52.5% (n=21) were mainly due to congenital anomalies of the kidney and urinary tract; chronic glomerulonephritis was responsible for 20% of cases (n=8). Most patients initiated HD with a CVC (n=35, 87.5%), including two patients with an arteriovenous fistula (AVF) who required a temporary CVC until fistula maturation. At the end of follow-up, about 45% of the patients ended up with an AVF (comparing to 17.5% at the beginning) and, not unexpectedly, 88.9% (n=16) of them weighed more than 30kg and only one child less than 15 kg. The mean duration of dialysis was 1.2±1.8 years (1 month-8 years); 24 patients were submitted to KT (60%), 6 transferred to PD (15%) and only 4 remain on HD. Average waiting times for KT are quite longer in patients with AFV (1.7±2 years), in comparison to CVC (0.4±0.3 years). Conclusion CVC is by far the most used access in incident patients starting on HD. In our center it seems justified by the anatomical limitations of younger and smaller patients, as wells as expected shorter awaiting time for KT. Infectious and mechanical complications must be weighed when using CVC, mainly considering the probable need for different renal replacing techniques over the years. Although our data is quite similar to several international reports and other center experiences, we still aim for the best, with an expected improvement of these results within the coming years. For now, a notable increase in AVF placement at the end of the follow-up is already an encouraging fact.