Arteriovenous Fistula Failure Rate Research Articles

#2924 Comparison of large language models and traditional natural language processing techniques in predicting arteriovenous fistula failure

Abstract Background and Aims Large language models (LLMs) have gained significant attention in the field of natural language processing (NLP), marking a shift from traditional techniques like Term Frequency-Inverse Document Frequency (TF-IDF). We developed a traditional NLP model to predict arteriovenous fistula (AVF) failure within next 30 days using clinical notes. The goal of this analysis was to investigate whether LLMs would outperform traditional NLP techniques, specifically in the context of predicting AVF failure within the next 30 days using clinical notes. Method We defined AVF failure as the change in status from active to permanently unusable status or temporarily unusable status. We used data from a large kidney care network from January 2021 to December 2021. Two models were created using LLMs and traditional TF-IDF technique. We used “distilbert-base-uncased”, a distilled version of BERT base model [1], and compared its performance with traditional TF-IDF-based NLP techniques. The dataset was randomly divided into 60% training, 20% validation and 20% test dataset. The test data, comprising of unseen patients’ data was used to evaluate the performance of the model. Both models were evaluated using metrics such as area under the receiver operating curve (AUROC), accuracy, sensitivity, and specificity. Results The incidence of 30 days AVF failure rate was 2.3% in the population. Both LLMs and traditional showed similar overall performance as summarized in Table 1. Notably, LLMs showed marginally better performance in certain evaluation metrics. Both models had same AUROC of 0.64 on test data. The accuracy and balanced accuracy for LLMs were 72.9% and 59.7%, respectively, compared to 70.9% and 59.6% for the traditional TF-IDF approach. In terms of specificity, LLMs scored 73.2%, slightly higher than the 71.2% observed for traditional NLP methods. However, LLMs had a lower sensitivity of 46.1% compared to 48% for traditional NLP. However, it is worth noting that training on LLMs took considerably longer than TF-IDF. Moreover, it also used higher computational resources such as utilization of graphics processing units (GPU) instances in cloud-based services, leading to higher cost. Conclusion In our study, we discovered that advanced LLMs perform comparably to traditional TF-IDF modeling techniques in predicting the failure of AVF. Both models demonstrated identical AUROC. While specificity was higher in LLMs compared to traditional NLP, sensitivity was higher in traditional NLP compared to LLMs. LLM was fine-tuned with a limited dataset, which could have influenced its performance to be similar to that of traditional NLP methods. This finding suggests that while LLMs may excel in certain scenarios, such as performing in-depth sentiment analysis of patient data for complex tasks, their effectiveness is highly dependent on the specific use case. It is crucial to weigh the benefits against the resources required for LLMs, as they can be significantly more resource-intensive and costly compared to traditional TF-IDF methods. This highlights the importance of a use-case-driven approach in selecting the appropriate NLP technique for healthcare applications.

Comparison of clinical examination, doppler and fistulogram for arterio-venous fistula surveillance in detecting secondary failure.

Arteriovenous Fistula (AVF) surveillance is required to detect early dysfunction (thrombosis, stenosis) and its timely correction prolongs access-patency. Clinical examination (CE) and doppler have been used as screening/surveillance of AVF, for early detection of AVF dysfunction. Since there was inadequate evidence for KDOQI to make recommendations on AVF surveillance and on secondary failure rate. We compared CE, doppler and fistulogram as surveillance modalities in detecting a secondary failure in matured AVF. This prospective-observational, single-center study, was done between December 2019-April 2021. CKD stage 5 patients on dialysis/Not-on-dialysis with matured AVF were included at third month. CE, doppler (blood flow, vein diameter, depth), and fistulogram were done at third and sixth month. Secondary failure was assessed at sixth month classifying AVF to patent/functional and failed group. Diagnostic tests were performed by comparing three methods considering fistulogram as gold-standard. Residual urine output is also monitored to look for any contrast induced residual renal function loss. Of total 407 created AVF, 98 (24%) had primary failure. Twenty-five (6%) had surgical complications including unsuccessful AVF and aneurysm/rupture, 156 lost follow-up at third month, 104 consented patients were enrolled, 16 lost to follow-up subsequently, and 88 patients' data were analyzed at the end. At the sixth month, 76(86.4%) had patent AVF, 8 (9.1%) had secondary failure (Thrombosis-4, Central Venous Stenosis-4), and 4 (4.1%) patients expired. Considering fistulogram as a diagnostic standard, CE showed 87.5% sensitivity, and 93.4% specificity (cohen's kappa value of 0.66). Doppler had sensitivity and specificity of 87% and 96% respectively (cohen's kappa value of 0.75), Combination of clinical examination with doppler showed sensitivity and specificity of 100% and 89% respectively. Although the secondary AVF failure rate is less than the primary, CE is an important and valuable tool in the diagnosis and surveillance of AVF in detecting its dysfunction. Moreover, CE with doppler can be used as a surveillance protocol that can detect early AVF dysfunction at par with Fistulogram.

Far-Infrared Therapy Improves Arteriovenous Fistula Patency and Decreases Plasma Asymmetric Dimethylarginine in Patients with Advanced Diabetic Kidney Disease: A Prospective Randomized Controlled Trial.

Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase and plays a significant role in the pathogenesis of arteriovenous fistula (AVF) dysfunction. The aim of this study is to evaluate the effect of far-infrared (FIR) therapy on the maturation and patency of newly-created AVFs in patients with advanced diabetic kidney disease (DKD) as well as the concurrent change in plasma ADMA. The study enrolled 144 participants with advanced DKD where 101 patients were randomly allocated to the FIR therapy group (N = 50) and control group (N = 51). Patients receiving FIR therapy had a decreased AVF failure rate within 12 months (16% versus 35.3%; p = 0.027); decreased incremental change of ADMA concentration at the 3rd and 12th month; increased AVF blood flow at the 1st, 3rd, and 12th month; increased 3-month physiologic maturation rate (88% versus 68.6%; p = 0.034); increased 1-year unassisted AVF patency rate (84% versus 64.7%; p = 0.017); and increased clinical AVF maturation rate within 12 months (84% versus 62.7%; p = 0.029) compared to the control group. The study demonstrates that FIR therapy can reduce the incremental changes in plasma ADMA concentration, which may be associated with the improvement of AVF prognosis in patients with advanced DKD.

Clinical Characteristics and Outcome of Arteriovenous Fistula among Patients Undergoing Haemodialysis with end Stage Renal Disease

Objective: To determine the clinical characteristics and failure rate of arteriovenous fistula (AVF) among patients undergoing haemodialysis with end stage renal disease. Methodology: This was a cross-sectional study, done at department of urology at Bilawal Medical College for Boys, Liaquat University of Medial and Health Sciences Jamshoro Pakistan, with time duration of eleven months from April 2021 to February 2022. All the patients with age of more than 20 years, both genders, end stage renal disease and undergoing haemodialysis were included. The optimal site for fistula development was determined after taking blood pressure and completing the Allen test. Vascular diameter, intravascular thrombosis, arterial wall atherosclerosis, and the opening of arterial inflow and venous outflow access were all assessed during the procedure. End- to- side and side-to-side arteriovenous fistula were established if there were no contraindication. The patients were discharged after establishing the fistula's patency and experiencing the thrill. The patient's fistula patency and hemodialysis performance were assessed till six weeks. All the information was documented in the self-made proforma. SPSS version 26 was used for the data analysis. Results: A total of 100 cases were studied, most of the cases (49.0%) were more than 50 years old and males were most common 71.0%. Out of all, 59(59.0%) cases were diabetics and hypertensive. According to the site of arteriovenous fistulae (AVF), Left radio cephalic AVF was31.0%, left brachio cephalic AVF was 40.0%, left brachio basilic AVF 24.0%, right radio cephalic AVF 03.0%, right Brachio cephalic AVF 1.0% and right brachio basilic AVF 1.0%. At 6th week follow-up arteriovenous fistula was observed successfully functional in 91.0% cases, while 5.0% arteriovenous fistula were burst and in 3.0% it was failed, while one patient was died during this six-weeks follow-up. Conclusion: For haemodialysis, the arteriovenous fistula was observed to be the best and preferable option with higher functioning rate, noninvasive and lower complicated. Keywords: Renal failure, AVF, function, failure

An Investigation on the One-year Rate of Arteriovenous Fistula Failure and Its Related Factors in Patients with End-stage Renal Disease; an Experience in Golestan Province of Iran

Background: Aortic arch calcification (AAC) is very common in hemodialysis patients and is associated with cardiovascular events and the incidence of arteriovenous fistula (AVF) failure. In order to predict the prognosis of patients, a study was conducted to determine the annual failure rate of AVF and its related factors. Methods: This cross-sectional study was performed on 145 patients with end-stage renal disease (ESRD) who were AVF candidates, visiting a referral center in Golestan province of Iran. After the insertion of intravenous arterial fistulas, posterior-anterior chest x-rays were captured, and the grafts were classified by a radiologist. Patients were followed for one year, and the rates of fistula failure (FF) and cardiovascular mortality were recorded. Finally, the data were entered into SPSS 19 software and analyzed by the Chi-square test. Results: Of 112 patients followed up for one year, 56.2% were men. During the one-year follow-up period, 5.3% of the patients developed arteriovenous FF, and this event was more common in men, but the difference was not statistically significant. The majority of the AVF candidates had a history of diabetes and hypertension, but no association was found between the one-year FF rate and these two diseases. Nearly 7.7% of the patients had grade III calcification, but no significant relationship was observed between the AAC grade and AVF failure rate. Conclusions: The rate of one-year FF was higher among ESRD patients with a history of chronic kidney diseases. Our results also demonstrated that the mortality rate is higher in patients with a high degree of AAC and patients with medical history (cardiovascular disease and diabetes).

SAT-217 COMPLICATIONS OF ARTERIO-VENOUS FISTULA AS A VASCULAR ACCESS IN HEMODIALYSIS PATIENTS- A HOSPITAL BASED STUDY

Vascular access is required for hemodialysis and arterio-venous fistula is the preferred access. It is the life line for patients on hemodialysis. Various guidelines have recommended monitoring and surveillance of arterio-venous fistula as a standard of care. Clinical examination can detect most of the complications. This study looked into various complications of arterio-venous fistula as a vascular access in hemodialysis patients. The study was conducted in the hemodialysis unit of a Teaching Hospital in Central Nepal from January 2017 till December 2017. Ethical clearance was taken from IRC, Nepal Medical College. Patients undergoing hemodialysis for at least 3 months were enrolled in the study. After informed and written consent, clinical examination and colour doppler ultrasound of the arterio-venous fistula was done. The physicians performing the clinical examination and the colour doppler examination were blinded to remove bias. Clinical, socio-demographic and biochemical parameters were recorded. Statistical analysis was done using Statistical Package for the Social Sciences software version 20 and Epi-info software version 7. Total study population was 102. The patency of arterio-venous fistula was seen in 91%. Primary failure was present in 15.7%. The different complications observed were pseudoaneurysm (16.7%), thrombus formation (17.6%), venous outflow stenosis (9.8%), juxta-anastomostic stenosis (8.8%), central vein stenosis (8.8%), extravascular hematoma (4.9%), megafistula (4.9%) and infection (2.9%). Sensitivity and specificity of clinical examination as compared to colour doppler ultrasound was 88% and 95% which varied with different complications. Secondary failure rate of arterio-venous fistula was 13.7%. The average blood flow rate across the AVF in the complications group was much higher (2183 ml/min) and was statistically significant (p=0.002). Female sex, high venous pressure, history of primary failure of AVF, Tuberculosis, higher pre dialysis systolic and diastolic blood pressure, low BMI and secondary AVF failure were statistically significant for complications associated with AVF. Presence of strong palpable pulsations on clinical examination of AVF was statistically significant parameter which identified complications of AVF.TableShowing Validity of clinical examination as compared to colour doppler ultrasound examination in detecting complications of AVF.ComplicationsSensitivity (%)(95% CI)Specificity (%)(95% CI)Positive Predictive Value (%) (95% CI)Negative Predictive Value (%) (95% CI)Thrombus87.5 (61.6-98.4)95.3 (88.5-98.7)77.7 (56.9-90.2)97.6 (91.8-99.3)Pseudoaneurysm71.4 (47.8-88.7)97.5 (91.3-99.7)88.2 (65.0-96.0)92.9 (87.1-96.2)Stenosis95.4 (77.1-99.8)91.2 (82.8-96.4)75 (59.5-85.9)98.6 (91.4-99.8)Infection40 (5.27-85.3)98.9 (94.3-99.7)66.6 (17.7-94.8)96.9 (93.9-98.5)Hematoma40 (5.3-85.4)96.9 (91.2-99.3)40 (12.4-75.8)96.9 (93.8-98.4) Open table in a new tab Arterio-venous fistula is associated with higher rate of complications. Clinical examination is highly sensitive and specific but underutilized tool to detect the complications of arterio-venous fistula. Colour doppler ultrasonographic examination should also be done to look into hemodynamics of associated AVF and managed accordingly. Monitoring and surveillance of AVF should be performed as a standard of care in every hemodialysis centre.

3:36 PM Abstract No. 17 Endovascular arteriovenous fistula creation: a single-center retrospective review of early experience with both WavelinQ and Ellipsys

Arteriovenous fistula (AVF) is the preferred dialysis access for ESRD patients. However, the primary failure rate of AVF is around 50%. Traditionally, AVF’s were created in the OR using an open technique. In the past 2 years, the FDA approved two new devices, WavelinQ and Ellipsys, for endovascular fistula creation. Here we review our early endoAVF outcomes and compare the two systems. All patients referred to our access program were screened by ultrasound evaluation and vessel sizes were measured. Patients were selected for each device type based on vascular anatomy. The endoAVF procedures were performed by a multidisciplinary team (interventional radiologists and nephrologists). Post procedure ultrasounds were performed between 2-6 weeks after endoAVF procedure, fistula blood flow and vessel diameter were measured. To date, our institution has successfully placed 16 of 17 endoAVF’s (6 WavelinQ, 10 Ellipsys). Average patient age was 59.4 years, with 3 women and 13 men. In the WavelinQ group, the avg blood flow 2-4 weeks post AVF creation was 537 mL/min, the diameter of the outflow vein is 6.3 mm. The cephalic vein is the dominant outflow in 17%. 3/6 WavelinQ systems matured within an avg of 47 days. 1 required additional intervention. 2/3 of the immature WavelinQ’s require basilic vein transposition. In Ellipsys, the average blood flow 2-4 weeks post AVF creation was 562 mL/min, the diameter of the outflow vein is 5.7 mm. The dominant outflow is the cephalic vein in 70%. 7 patients required an additional 9 procedures including anastomotic angioplasty (n = 4), ligation of collateral veins (n = 4), ligation of collateral veins (n = 1). 3/10 Ellipsys systems matured within an avg time of 57 days. In summary, endoAVF creation using WavelinQ and Ellipsys is technically feasible. Compared to WavelinQ, Ellipsys groups may require more additional procedures to achieve maturation. Patients with dominant basilic outflow may also require surgical transposition. EndoAVF is a novel technique that IR’s can utilize to create hemodialysis access; however, interventionalists must understand appropriate patient evaluation/selection, and learn variations in technique specific to each unique system.

The Role of Far Infrared Therapy in the Unassisted Maturation of Arterio-venous Fistula in Patients with Chronic Kidney Disease.

Introduction:The goal of arterio-venous fistula (AVF) creation is to achieve a well-functioning access that can be cannulated repetitively and can provide adequate flow for the dialysis. The objective of this study was to assess the role of far infrared (FIR) therapy in the unassisted maturation of newly created AVF in patients with chronic kidney disease (CKD).Materials and Methods:In this prospective open labeled randomised control trial, 107 patients were randomized. Participants in the control arm received oral clopidogrel 75 mg once daily for 30 days along with isometric hand exercise, whereas those in the test arm received FIR therapy twice weekly, 40 min session each, for 4 weeks. A biopsy from venous end was taken during fistula surgery. Doppler study of AVF was done at the end of the 4th and 12th week to assess AVF. Vascular access guidelines proposed by National Kidney Foundation –Kidney Disease Outcomes Quality Initiative (NKF- KDOQI) in 2006 were adapted to define the maturation of AVF.Results:Out of 107 patients, 51 were randomized to the test arm and 56 to the control arm. During follow-up, the blood flow rate through AVF (Qa) and the diameter of the cephalic vein draining (CVd) the AVF were measured. At the end of 3 months, Qa in Radio-Cephalic Fistula (RCF) was high in the test arm (p–0.003). The AVF failures were 5 (10.2%) and 14 (28%) in the test and control arms, respectively (p: 0.025). However, when adjusted for AVF failure within 6 h of surgery (may be related to surgical technique) this difference in AVF patency was statistically insignificant (p: 0.121). The mean Qa was high in patients with an arterial intimal medial thickness (AIMT) <0.5 mm. The IMT of the anastomosed artery had statistically significant correlation with the primary failure rate of AVF (P < 0.001).Conclusion:In patients with CKD, FIR therapy was effective in increasing the AVF blood flow rate at the end of 3 months, though the difference in primary failure rate was statistically insignificant.

Intraoperative Bloodflow Rate as a Predictor for Maturity of Radiocephalic Arteriovenous Fistula

Background: Arteriovenous fistula (AVF) is the best access for hemodialysis. The failure of arteriovenous fistula maturation is currently a major problem faced today. This study aims to assess whether an intraoperative bloodflow rate measured with Doppler ultrasound can be a predictor of the maturity of radiocephalic AVF. Subjects and Methods: Subjects were patients to be made radiocephalic AVF with USG mapping according to the standard. Shortly after, the anastomosis bloodflow rate was measured with a linear probe Doppler ultrasound. This study used cross sectional analytic design to obtain radiocephalic AVF maturation relationship with intraoperative bloodflow rate. Results: Radiocephalic AVF ( n = 71) in 71 patients were made and evaluated in 6 weeks. The mean intraoperative bloodflow rate in mature fistulas was significantly higher than those which did not mature (201.85 and 141.96 mL/min; P 165.5 mL/min has a good predictor value for radiocephalic AVF maturation, so it can be used as reference to determine whether the surgeon need for further assessment and revision intraoperatively, which in turn is expected to decrease the maturation failure rate of arteriovenous fistula. Keywords : arteriovenous fistula , bloodflow rate, maturity predictor

Dialysis Arteriovenous Fistula Failure and Angioplasty: Intimal Hyperplasia and Other Causes of Access Failure

The arteriovenous fistula (AVF) is the preferred hemodialysis access type because it has better patency rates and fewer complications than other access types. However, primary failure remains a common problem impeding AVF maturation and adding to patients' morbidity and mortality. Juxta-anastomotic (or inflow) stenosis is the most common reason leading to primary failure, and percutaneous transluminal angioplasty continues to be the gold-standard treatment with excellent success rates. Intimal hyperplasia (IH) has been traditionally blamed as the main pathophysiologic culprit, but new evidence raises doubts regarding the contribution of IH alone to primary failure. We report a 64-year-old man with a 2-stage brachiobasilic AVF that was complicated by failure 4 months after creation. An angiogram showed multiple juxta-anastomotic and midfistula stenotic lesions. Percutaneous transluminal angioplasty was successful in assisting maturation and subsequently cannulating the AVF for hemodialysis treatment. We failed to identify the underlying cause of stenosis because biopsy specimens from fistula tissue obtained at the time of transposition revealed no occlusive IH. This case emphasizes the need for additional research on factors contributing to AVF failure besides IH and highlights the need for more therapeutic options to reduce AVF failure rate.

Effect of ethnicity and socioeconomic status on vascular access provision and performance in an urban NHS hospital.

BackgroundThe aim of this study was to examine the effect of ethnicity, socioeconomic group (SEG) and comorbidities on provision of vascular access for haemodialysis (HD).MethodsThis was a retrospective review of two databases of HD sessions and access operations from 2003–11. Access modality of first HD session and details of transplanted patients were derived from the renal database. Follow-up was until 1 January 2015. Primary failure (PF) was defined as an arteriovenous fistula (AVF) used for fewer than six consecutive dialysis sessions. AVF survival was defined as being until the date the AVF was abandoned. Ethnicity was coded from hospital records. SEG was calculated from postcodes and 2011 census data from the Office of National Statistics. Comorbidities were calculated with the Charlson Comorbidity Index.ResultsFive hundred incident patients started chronic HD in the study period. Mode of starting HD was not associated with ethnicity (P = 0.27) or SEG (P = 0.45). Patients from ethnic minorities were younger when starting dialysis (P < 0.0001). Some 928 AVF patients' first AVF operations were analysed: 68% Caucasian, 26% Asian and 6% Afro-Caribbean. Half were in the most deprived SEG and 11% in the least deprived SEG. PF did not differ by ethnicity (P = 0.29), SEG (P = 0.75) or comorbidities (P = 0.54). AVF survival was not different according to ethnicity (P = 0.13) or SEG (P = 0.87). AVF survival was better for patients with a low comorbidity score (P = 0.04). The distribution of transplant recipients by ethnic group and SEG was similar to the distributions of all HD starters.ConclusionEthnicity and socioeconomic group had no effect on mode of starting HD, primary AVF failure rate or AVF survival. Ethnic minorities were younger at start of dialysis and at their first AVF operation.

Comparison of success rate of arterio-venous fistula in patients with diabetes vs non-diabetes

Introduction and objective: Definition of chronic renal disease is based on the presence of kidney damage or glomerular filtration rate (GFR 60 ml/min per 1.73 m2) for 3 months, irrespective of cause[1]. Once they are diagnosed as CKD, they are kept either on hemodialysis or peritoneal dialysis or patient undergo renal transplant.[2,3] With this research we may prove that even in a similar circumstances failure rate of AVF is more in diabetes patient.Materials and Methods: Total 50 patients of either gender were taken in this study. Inclusion criteria: CRF with GFR &lt;30ml/min. Arterial diameter &gt;1.5mm and venous diameter &gt;2mm. Preoperative radial artery blood flow &gt;30cm/min. Exclusion criteria: arterial diameter &lt;1.5mm venous diameter &lt;2mm.Written consent was taken from the patient. After preoperative workup surgery was done by 1st author. Arterio-venous fistula was scanned by color Doppler imaging after 4 weeks.Result: There were 31[62%] male, 19[38%] female. Mean age of patients was 55.8 years. 18[36%] were dialysis dependent. Cause of renal failure were diabetes 16(32%), unknown 15(30%), glomerulonephritis 8[16%] and obstructive uropathy 3[6%]. Mean internal diameter of radial artery was 1.91mm [1.5-2.6] and cephalic vein 2.57mm [1.9-3.2].7 patients had swelling of arm, 5 patients has surgical site infections and 15 patients had primary failure; 11 were from diabetic group and 4 from non-diabetic group. Mean duration of surgery was 60.95 minutes [50-75]. Average preoperative velocity in radial artery was 32.94[30-39]cm/sec. Average flow of blood at the end of 4 weeks was 461.42ml/min [0-654]. Between two groups failure rate was significantly high in diabetic patients [p = 0.02]. Failure rate was significantly higher in patients with diabetes more than 10 years [p=0.01].Conclusion: Failure rate of arterio-venous fistula is significantly high in diabetic patients.

Comparision of success rate of arterio-venous fistula in patients with diabetes vs non-diabetes

Introduction: Definition of chronic renal disease is based on the presence of kidney damage or glomerular filtration rate (GFR 60 ml/min per 1.73 m2) for 3 months, irrespective of cause. Once they are diagnosed as CKD, they are kept either on hemodialysis or peritoneal dialysis or patient undergo renal transplant. With this research we may prove that even in a similar circumstances failure rate of AVF is more in diabetes patient.&#x0D; Methods: Total 50 patients of either gender were taken in this study. Inclusion criteria: CRF with GFR &lt;30ml/min. Arterial diameter &gt;1.5mm and venous diameter &gt;2mm. Preoperative radial artery blood flow &gt;30cm/min. Exclusion criteria: arterial diameter &lt;1.5mm venous diameter &lt;2mm. Written consent was taken from the patient. After preoperative workup surgery was done by 1st author. Arterio-venous fistula was scanned by color Doppler imaging after 4 weeks.&#x0D; Result: There were 31 [62%] male, 19 [38%] female. Mean age of patients was 55.8 years. 18(36%) were dialysis dependent. Cause of renal failure were diabetes 16(32%), unknown 15(30%), glomerulonephritis 8(16%) and obstructive uropathy 3(6%). Mean internal diameter of radial artery was 1.91mm (1.5-2.6) and cephalic vein 2.57mm (1.9-3.2). 7 patients had swelling of arm, 5 patients has surgical site infections and 15 patients had primary failure; 11 were from diabetic group and 4 from non-diabetic group. Mean duration of surgery was 60.95 minutes (50-75). Average preoperative velocity in radial artery was 32.94(30-39) cm/sec. Average flow of blood at the end of 4 weeks was 461.42ml/min (0-654). Between two groups failure rate was significantly high in diabetic patients (p = 0.02). Failure rate was significantly higher in patients with diabetes more than 10 years (p=0.01).&#x0D; Conclusion: Failure rate of arterio-venous fistula is significantly high in diabetic patients.

Pre-existing Arterial Micro-Calcification Predicts Primary Unassisted Arteriovenous Fistula Failure in Incident Hemodialysis Patients.

Vascular access micro-calcification is a risk factor for cardiovascular morbidity and mortality in hemodialysis (HD) patients but its influence on vascular access patency is still undetermined. Our study aimed to determine the impact of arterial micro-calcification (AMiC) on the patency of vascular access in HD patients. One-hundred fourteen HD patients receiving arteriovenous fistula (AVF) operation were included in this study. During the operation, we obtained partial arterial specimen and performed pathological examination by von Kossa stain to identify AMiC. We compared primary unassisted AVF failure within 1 year between positive and negative AMiC groups, and performed Cox regression analysis for evaluating risk factor of AVF failure. The incidence of AMiC was 37.7% and AVF failure occurred in 45 patients (39.5%). The AVF failure rate within 1 year was greater in the positive AMiC group than those in the negative AMiC group (53.5% vs. 31.0%, p = 0.02). Kaplan-Meier analysis showed that the positive AMiC group had a lower AVF patency rate than the negative AMiC group (p = 0.02). The presence of AMiC was an independent risk factor for AVF failure. In conclusion, preexisting AMiC of the vascular access is associated with primary unassisted AVF failure in incident HD patients.

Arterio-Venous (AV) Fistula: Surgical outcome in College of Medical Sciences Teaching Hospital, Bharatpur, Chitwan

Aims Arteriovenous fistula is considered as reliable form of vascular access for hemodialysis in Chronic Kidney Disease (CKD) patients. We aim to evaluate prospectively, the outcome and primary failure rate of Arteriovenous fistula in 30 Chronic kidney Disease patients with Glomerular Filtration Rate (GFR) &lt;30ml/min. Materials and methods This prospective study was conducted at the department of cardiothoracic and vascular surgery (CTVS), College of Medical Sciences, Bharatpur from May 2011 to May 2012. Thirty patients ranging from age 25 to 76 years with stage IV and V CKD, i.e. GFR below 30ml/min, were included in this study. Detailed physical examination including arterial pulses i.e. axillary, brachial, radial and ulnar and blood pressure in both upper limbs was recorded. Allens test was performed on every patient and left upper limb was used for AV fistula formation. Brachiocephalic fistula was made in 19 (63.33%), while radiocephalic fistula was made in 11 (36.67%) patients. Patients were evaluated post operatively, on outdoor basis, weekly for 6weeks. All patients were evaluated for the presence or absence of complications i.e. infection, hematoma, thrombosis, aneurysms and steal syndrome. Results The complication was primary failure in two patients. One male patient got secondary infection and one female patient got post operative hematoma leading to 6.66% primary failure of fistula. No other complications were noted. Conclusion Arteriovenous fistula is the gold standard for vascular access for hemodialysis in patients with deteriorating renal function and end-stage renal disease. It is designed to improve the effectiveness of dialysis with fewer risks and complications than other vascular accesses. This study gives the higher success rate of 93.33% and concludes that age should not be a limiting factor when determining candidacy for arteriovenous fistula creation and is the safe procedure. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-4, 1-6 DOI: http://dx.doi.org/10.3126/jcmsn.v8i4.8693

Pre-operative Radial Arterial Diameter Predicts Early Failure of Arteriovenous Fistula (AVF) for Haemodialysis

Long term patency of arteriovenous fistula (AVF) is relevant to the management of end stage renal failure (ESRF) patients on haemodialysis (HD). We evaluated the role of routine radial arterial duplex for imaging radial artery before AVF formation to investigate the relationaship between radial artery internal diameter (ID) and AVF patency. 21 patients with ESRF were examined by duplex sonography before AVF formation, 1 day, 1 week, 4 week and 12 weeks post AVF formation. For assessment of AVF patency, patients were divided into 2 groups. Group-1, 11 patients with radial artery ID <1.5mm and Group-2, 10 patients with radial artery ID >1.5mm. Measurement of radial artery blood inflow rate was calculated from mean blood flow velocity and vessel diameter. All AVFs were constructed on the forearm using autologous veins. In Group-1, 5 patients (45%) showed immediate thrombosis of AVF graft. All patients in group-2 had patent AVF at 12 weeks. Pre-AVF formation radial artery blood inflow rate between two groups was not significantly different (p=0.06). Radial artery blood inflow rate was consistently and significantly higher in group-2 at all later time points with p value of <0.01 (Mann Whitney test). There was a high failure rate of AVF with radial artery ID of <1.5mm. In the presence of small radial arteries primary access AVF in the upper arm should be considered.