Arteriovenous Fistula Stenosis Research Articles

Contrast Venography Versus Intravenous Ultrasound in Hemodialysis Arteriovenous Access Dysfunction

Contrast Venography Versus Intravenous Ultrasound in Hemodialysis Arteriovenous Access Dysfunction

#4524 TRIBOELECTRIC EVALUATION OF ARTERIOVENOUS FISTULA FOR HAEMODIALYSIS: A PILOT STUDY

Abstract Background and Aims Determination of stenosis in an arteriovenous fistula (AVF) for hemodialysis is an essential step in the management of patients with end-stage kidney disease. Stenosis, or narrowing of the blood vessels, can significantly reduce blood flow and ultimately lead to thrombosis and dysfunction of the AVF. Therefore, accurate and frequent surveillance is crucial for detection of stenosis and for the proper management of AVF. Surveillance of AVF is based on direct methods including ultrasound imaging and magnetic resonance angiography both dependent from examiner availability and not ever regularly repeatable. The triboelectric effect refers to the phenomenon where certain materials become charged after coming into contact with another material. In blood vessels the rubbing of erythrocytes against each other and arterial and vein wall generates a negative triboelectric charge and an electric potential range directly related to flow rate. The aim of our study was firstly to investigate the potential reliability of a wearable device able (Figure 1A) to record this constant potential and consequently evaluating the aptitude of waveforms generated to detect AVF stenosis in comparison to standard doppler evaluation. Method Between September 2022 and January 2023, we screened forty-eight patients from two hemodialysis centers in Catanzaro (Italy) Patients were divided in two groups basing on the assessment from two blinded experienced examiners for recognized criteria for stenosis: 2 major criteria (reduction of vessel size greater than 50% and a ratio between systolic peak velocity (SPV) in the stenotic region and SPV in pre-stenotic region major of 2 (>2)) and a supplementary finding like drop of the access flow [QA] below 500ml/min or drop of QA>25% as compared to the previous measurements in FAV with QA<1000ml/min or residual diameter <2mm). Patients were then evaluated using the PVDF/Kapton triboelectric sensor placed in contact with the skin on the lower surface, and with the thumb in contact with the upper surface to close the circuit and graphically recording typical pattern waveform generated. AVFs were analyzed considering the following acquisition sites: the chamber which corresponds to the site where surgery anastomosis was performed, a site located 5 cm from the chamber, and finally at the level of the humeral artery. Results There was an almost perfect (R = 0.97) correlation between the blood flow measured at the humeral artery level and the maximum-time derivative equation computed for each patient (Figure 1B). Based on doppler evaluation, 14/48 patients (29%) were classified as stenotic. Of these, 13 patients (93%) presented a typical wave pattern (B-point) with a ‘Notch’ shape (Figure 1D) which, conversely, was found in only 1 patient out of 34 without evidence of stenosis. The presence of Notch reflected the presence of stenosis with a Sensitivity of 92,8% (95%CI 66,1 to 99,8%), a specificity of 97% (95%CI 84,7 to 99,9%), holding an overall accuracy of 95,8% (95%CI 85,7% to 99,5%). Patients without stenosis assumed a different waveform (Figure 1C). Conclusions In chronic hemodialysis patients, the evaluation of AVF by a biosensor based on triboelectric potential measurement might represent an accurate and easy-to-perform surrogate of standard eco-doppler method for a quick and reliable evaluation of AVF functioning and, particularly, for a rapid risk stratification of patients with high suspect of AVF stenosis.

Cost-Effectiveness of Drug-Coated Balloon Angioplasty versus Plain Old Balloon Angioplasty for Arteriovenous Fistula Stenosis.

To compare the cost-effectiveness of drug-coated balloon angioplasty (DCB) versus plain old balloon angioplasty (POBA) for treatment of arteriovenous fistula (AVF) stenosis. A Markov model was created to compare DCB versus POBA for AVF stenosis over a 2-year time horizon from a United States payer's perspective. Probabilities related to complications, restenosis, retreatment, and all-cause mortality were obtained from published literature. Costs were calculated using Medicare reimbursement rates and data from published cost analyses, inflation-adjusted to 2021. Health outcomes were measured with quality-adjusted life years (QALY). Probabilistic and deterministic sensitivity analyses were performed with a willingness-to-pay threshold of $100,000/QALY. Base case calculation showed better quality-of-life outcomes but increased cost with POBA compared to DCB, with an incremental cost-effectiveness ratio of $27,413/QALY, making POBA the more cost-effective strategy in the base case model. Sensitivity analyses showed that DCB becomes cost-effective if the 24-month mortality rate after DCB is no more than 3.4% higher than that after POBA. In secondary analyses where mortality rates were equalized, DCB was more cost-effective than POBA until its additional cost reached more than $4213 per intervention. When modeled from a payer's perspective over 2years, the cost utility of DCB versus POBA varies with mortality outcomes. POBA is cost-effective if 2-year all-cause mortality after DCB is greater than 3.4% higher than after POBA. If 2-year mortality after DCB is less than 3.4% higher than after POBA, DCB is cost-effective until its additional cost per procedure exceeds $4213 more than POBA. HISTORICALLY CONTROLLED STUDY.: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Prospective, randomized, multicenter clinical study comparing a self-expanding covered stent to percutaneous transluminal angioplasty for treatment of upper extremity hemodialysis arteriovenous fistula stenosis

Use of a covered stent after percutaneous transluminal angioplasty (PTA) was compared to PTA alone for treatment of upper extremity hemodialysis patients with arteriovenous fistula (AVF) stenoses. Patients with AVF stenosis of 50% or more and evidence of AVF dysfunction underwent treatment with PTA followed by randomization of 142 patients to include a covered stent or 138 patients with PTA alone. Primary outcomes were 30-day safety, powered for noninferiority, and six-month target lesion primary patency (TLPP), powered to test whether TLPP after covered-stent placement was superior to PTA alone. Twelve-month TLPP and six-month access circuit primary patency (ACPP) were also hypothesis tested while additional clinical outcomes were observed through two years. Safety was significantly non-inferior while six- and 12-month TLPP were each superior for the covered stent group compared to PTA alone (six months: 78.7% versus 55.8%; 12 months: 47.9% versus 21.2%, respectively). ACPP was not statistically different between groups at six-months. Observed differences at 24 months favored the covered-stent group: 28.4% better TLPP, fewer target-lesion reinterventions (1.6 ± 1.6 versus 2.8 ± 2.0), and a longer mean time between target-lesion reinterventions (380.4 ± 249.5 versus 217.6 ± 158.4 days). Thus, our multicenter, prospective, randomized study of a covered stent used to treat AVF stenosis demonstrated noninferior safety with better TLPP and fewer target-lesion reinterventions than PTA alone through 24 months.

THROMBECTOMY IN PATIENTS WITH THROMBOSIS OF ARTERIO-VENOUS FISTULA: CASE SERIES

Introduction. Thanks to the use of renal replacement therapy at the current stage of medical development, complete medical and social rehabilitation of patients with end-stage chronic renal failure is possible. The key to effective programmed hemodialysis is the formation of adequate permanent vascular access. Ensuring the optimal use and functioning of permanent vascular access is a multidisciplinary challenge. Currently, none of the known options for permanent vascular access is ideal, but a native arteriovenous fistula meets the requirements to a greater extent. Complications from vascular access for hemodialysis remain relevant for their solution today. The most common complication of vascular access is thrombosis of an arteriovenous fistula. For patients with chronic renal failure who are on programmed hemodialysis, thrombosis of vascular access is a great danger, which ultimately can lead to the impossibility of further hemodialysis and is the main reason for hospitalization and high mortality of this contingent of patients and needs an urgent solution.
 Clinical cases. 17 patients underwent thrombectomy from the subcutaneous "fistula". vein of the upper extremity. The age of the patients was 49.0 (44.0-61.0) years. By gender, the studied patients were distributed as follows: women - 9 (53%), men - 8 (47%). Among 17 (100%) operated patients, 12 (71%) had late thrombosis, 5 (29%) had early thrombosis of arteriovenous fistula,. Of 5 (100%) patients with early thrombosis of arteriovenous fistula, thrombectomy was effective in 2 (40%) patients (p=0.038). On the other hand, in 12 (100%) patients with late thrombosis of arteriovenous fistula, thrombectomy was successful in only 4 (33%) cases.
 Discussion. The cause of thrombosis of any vascular anastomosis is primarily hyperplasia of the neointima due to the proliferation of smooth muscle cells of the vascular wall. This circumstance leads to the formation of stenosis of the anastomosis, and as soon as the stenosis values become hemodynamically significant (> 50% of the lumen of the vessel), the risk of developing thrombosis increases by more than 50%. Thrombectomy alone is insufficient to restore patency of the permanent vascular access in the long term, as flow-limiting stenosis is present in more than 85% of cases.
 Conclusions. Neointimal hyperplasia is the main cause of progressive stenosis of arteriovenous fistula and subsequent thrombosis. Thrombectomy is indicated for thrombosis of arteriovenous fistula in the early postoperative period (up to 30 days after arteriovenous fistula formation). Thrombectomy alone is not enough to restore the patency of the permanent vascular access in the long term, and the final treatment requires its reconstruction at an early stage or the creation of a new arteriovenous fistula.

Abstract No. 30 Final Two-Year Results of the Prospective, Randomized AVeNEW Trial Comparing the Covera Covered Stent to Angioplasty for Treatment of Stenosis in Dysfunctional Hemodialysis Arteriovenous Fistula

Abstract No. 30 Final Two-Year Results of the Prospective, Randomized AVeNEW Trial Comparing the Covera Covered Stent to Angioplasty for Treatment of Stenosis in Dysfunctional Hemodialysis Arteriovenous Fistula

Identification and Validation of Hub Genes in the Stenosis of Arteriovenous Fistula.

Arteriovenous fistula (AVF) is the most widely used hemodialysis vascular access in China. However, stenosis of the AVF limits its use. The mechanism of AVF stenosis is currently unknown. Therefore, the purpose of our study was to explore the mechanisms of AVF stenosis. In this study, we identified the differentially expressed genes (DEGs) based on the Gene Expression Omnibus (GEO) dataset (GSE39488) between venous segments of AVF and normal veins. A protein-protein interaction (PPI) network was constructed to identify hub genes of AVF stenosis. Finally, six hub genes (FOS, NR4A2, EGR2, CXCR4, ATF3, and SERPINE1) were found. Combined with the results of the PPI network analysis and literature search, FOS and NR4A2 were selected as the target genes for further investigation. We validated the bioinformatic results via reverse transcription PCR (RT-PCR) and Western blot analyses on human and rat samples. The expression levels of the mRNA and protein of FOS and NR4A2 were upregulated in both human and rat samples. In summary, we found that FOS may play an important role in AVF stenosis, which could be a potential therapeutic target of AVF stenosis.

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis.

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

Retracted: Risk Factors of Arteriovenous Fistula Stenosis of Patients with Maintenance Hemodialysis.

[This retracts the article DOI: 10.1155/2022/2968122.].

Retracted: Role and Mechanism of Epithelial-Mesenchymal Transition Mediated by Inflammatory Stress-Induced TGF-β1 in Promoting Arteriovenous Fistula Stenosis.

[This retracts the article DOI: 10.1155/2022/9454843.].

Lumen diameter is associated with the patency after percutaneous angioplasty of arteriovenous fistulas.

To assess the value of lumen diameter after percutaneous angioplasty (PTA) to predict functional dialysis use (FDU) of arteriovenous fistulas (AVF). We performed a retrospective study of all patients who underwent first PTA because of AVF stenosis between March 2019 and March 2021. The outcome was FDU of AVF at 6 months follow up. Independent factors of FDU were identified using multivariate regression analyses. Receiver operating characteristic (ROC) curve was performed to investigate the predictive ability of lumen diameter for FDU. A total 68 patients were included into this study and the AVF of 53 cases (77.9%) were good for FDU after 6 months. The AVF age was younger in failure group than that in success group (16.1 ± 9.1 months vs 28.3 ± 20.0 months, p = 0.026). Compared with failure group, the post-PTA minimum luminal diameter (MLD) was bigger in success group (4.5 [4.0-4.5 mm] vs 5.5 mm [4.5-5.5 mm], p < 0.001). Meanwhile, the gain of lumen diameter in success group was also bigger than that in failure group (2.5 mm [2.0-3.0 mm] in failure group vs 3.0 mm [2.75-3.5 mm] in success group, p = 0.012). The residual stenosis was higher in failure group than that in success group (30% [10%-40%] vs 10% [0%-20%], p = 0.003). Logistic regression showed that AVF age and post-PTA MLD were independent predictors of FDU. ROC analysis showed that the gain of lumen diameter, post-PTA MLD and improvement of stenosis were comparable to predict FDU. For post-PTA MLD, the area under ROC curve was 0.804 (95% CI, 0.681-0.927, p < 0.001). The best cutoff is 4.75 mm, with the sensitivity and specificity was 71.7% and 80.0%, respectively. AVF age and post-PTA MLD were independently predictors for FDU of AVF after PTA. To get the best performance, a minimum vein diameter of 4.75 mm should be obtained after angioplasty.

Angioplasty of Dysfunctional Dialysis Fistula or Graft with Resveratrol-Excipient and Paclitaxel-Coated Balloon Improves Primary Patency Rates Compared to Plain Angioplasty Alone.

In this prospective randomized single-blinded study (reg. ISRCTN11414306), 76 patients with a dysfunctional dialysis fistula or graft due to a single de novo or recurrent stenosis in the access circuit were randomized to receive either conventional PTA (POBA) as a standard of care (n = 38) or PTA + adjunctive PTA with a drug-coated (paclitaxel-resveratrol matrix) SeQuent® Please OTW balloon (n = 38, DCB). Patients were scheduled for follow-up PTA at 3, 6, 9, and 12 months. The time of clinically driven target-lesion reintervention rate (primary patency rate) after the index procedure was analyzed using the log-rank test. The primary patency rates at 12 months after the index procedure were 17% (DCB) vs. 11% (POBA). At 3 months, they were 87% vs. 74%, at 6 months they were 53% vs. 26%, and at 9 months they were 22% vs. 11%. The hazard ratio for DCB was 0.55 (95%CI 0.32 to 0.95). The median time needed for target-lesion reintervention was longer in the DCB group (181 days) than in the conventional PTA group (98 days, p = 0.019). We conclude that PTA with the paclitaxel-resveratrol drug-coated SeQuent® Please OTW balloon in patients with de novo or recurrent stenosis in dialysis arteriovenous fistulas or grafts prolongs the time needed for target lesion reintervention and improves primary patency rates in the first year after the index procedure.

A deep learning algorithm to quantify AVF stenosis and predict 6-month primary patency: a pilot study.

A deep convolutional neural network (DCNN) model that predicts the degree of arteriovenous fistula (AVF) stenosis and 6-month primary patency (PP) based on AVF shunt sounds was developed, and was compared with various machine learning (ML) models trained on patients' clinical data. Forty dysfunctional AVF patients were recruited prospectively, and AVF shunt sounds were recorded before and after percutaneous transluminal angioplasty using a wireless stethoscope. The audio files were converted to melspectrograms to predict the degree of AVF stenosis and 6-month PP. The diagnostic performance of the melspectrogram-based DCNN model (ResNet50) was compared with that of other ML models [i.e. logistic regression (LR), decision tree (DT) and support vector machine (SVM)], as well as the DCNN model (ResNet50) trained on patients' clinical data. Melspectrograms qualitatively reflected the degree of AVF stenosis by exhibiting a greater amplitude at mid-to-high frequency in the systolic phase with a more severe degree of stenosis, corresponding to a high-pitched bruit. The proposed melspectrogram-based DCNN model successfully predicted the degree of AVF stenosis. In predicting the 6-month PP, the area under the receiver operating characteristic curve of the melspectrogram-based DCNN model (ResNet50) (≥0.870) outperformed that of various ML models based on clinical data (LR, 0.783; DT, 0.766; SVM, 0.733) and that of the spiral-matrix DCNN model (0.828). The proposed melspectrogram-based DCNN model successfully predicted the degree of AVF stenosis and outperformed ML-based clinical models in predicting 6-month PP.

Liposuction to improve vascular access in hemodialysis patients with arteriovenous fistulas.

Arteriovenous fistulas (AVFs) are indispensable in the care of patients with end-stage renal disease requiring hemodialysis. Obesity is a common comorbidity in hemodialysis patients, often making AVF cannulation technically challenging. Liposuction can be performed for superficialization of the AVF without the need for an open superficialization procedure. The aim of the present study was to evaluate the outcomes of liposuction to improve AVF access for hemodialysis. We performed a retrospective medical record review of patients who had undergone liposuction over an AVF at our institution from January 2000 to September 2021. Data were collected on the demographics, medical comorbidities, AVF site and depth, AVF diameter and flow, operative details, surgical complications, and follow-up. A total of 19 patients had been referred by the hemodialysis clinic for liposuction. Their mean age was 55.5years, and their mean body mass index was 39.5kg/m2. Either liposuction alone or liposuction combined with minimal access direct lipectomy was performed to superficialize the AVF. All procedures were performed secondarily, after prior creation of the AVF. Of the 19 patients, 18 had had an upper AVF and 1 had had a lower extremity AVF graft. Of the 19 patients, 12 (63%) had proceeded to hemodialysis after one liposuction. The mean time to cannulation for 10 of these 12 patients was 52.1± 25.6days. Two of the 12 patients were excluded from the mean calculation to prevent skewing from their prolonged time to requiring dialysis initiation. Of the 19 patients, 2 had required additional liposuction sessions, and 1 had required AVF intervention after the first liposuction attempt before achieving successful cannulation. Four patients (21%) had had unsuccessful cannulation despite additional liposuction or AVF interventions owing to AVF stenosis or thrombosis. Overall, 15 of the 19 patients (79%) had successfully proceeded to dialysis in the same extremity. The mean access depth had decreased from 1.75cm before liposuction to 0.93cm after liposuction. The mean volume of fat removed was 92.3cm3. Of the 16 patients with prior dialysis catheters, 11 were eventually removed after surgery once the vascular site was accessible. The body mass index correlated positively with the interval to the first successful cannulation (r= 0.5881; P< .05). The surgical complications included two cases of cellulitis treated with oral antibiotics. The mean follow-up time was 38.3months. Our results have shown that liposuction can be performed safely in obese patients requiring hemodialysis and was successful in improved AVF access for 15 of the 19 patients (79%) in our cohort. Larger studies are needed to compare the outcomes of this technique with those of open superficialization.

Comparison of percutaneous transluminal angioplasty and surgical revision after intraoperative dilatation with biliary tract probes for arteriovenous fistula stenosis at juxta-anastomosis.

Percutaneous transluminal angioplasty (PTA) is widely used for stenosis of vascular access (VA) for hemodialysis. We aimed to evaluate the effectiveness of both PTA and surgical revision after intraoperative dilatation with biliary tract probes for juxta-anastomotic stenosis in autogenous radiocephalic arteriovenous fistulas (RCAVFs). We performed a retrospective analysis of PTA and surgical revision after intraoperative dilatation with biliary tract probes; these were the first interventions after RCAVF establishment in 112 patients with juxta-anastomotic stenosis. Anatomical (number of stenoses) and clinical variables (age and gender of the patient, time of hemodialysis, AVF age, presence of diabetes mellitus, and cause of end-stage renal disease) were reviewed. Technical success, clinical success, and post-intervention primary patency were evaluated. Our study enrolled 35 patients in the PTA group and 77 patients in the surgical revision group. Clinical and technical success rates of both groups were 100%. There were no complications, such as bleeding or hematomas. Using the Kaplan-Meier method, the post-intervention primary patency rates at 3, 6, 9, 12, 18, and 24months in the PTA group were 100%, 94.28%, 77.1%, 60%, 54.29%, and 45.71%, respectively, and those in the surgical revision group were 100%, 94.81%, 92.2%, 90.91%, 81.82%, and 76.62%, respectively. The post-intervention primary patency rates at 9-24months in the surgical revision group were significantly higher than those in the PTA group (χ2 = 19.04, p < 0.0001). The post-intervention long-term primary patency rate of surgical revision after intraoperative dilatation with biliary tract probes is higher than that of PTA for the first intervention of patients with juxta-anastomotic stenosis in RCAVFs. The surgical revision method is safe and effective, especially in hospitals that have not yet carried out PTA.

Hyperglycemia Induces Endothelial Dysfunction through Hedgehog Signaling-Mediated TNF-α Production

Abstract: When patients with diabetic factors undergo hemodialysis with an arteriovenous fistula (AVF), the fistula is prone to stenosis with unclear mechanism. As a dynamic barrier between the blood and the vessel wall, the endothelium is easily damaged by molecules in the blood, and the mechanism between its dysfunction and the pathogenesis of AVF is still unclear. In this study, we aimed to investigate the mechanism of endothelial dysfunction, and the interventions of endothelial function to rescue of AVF stenosis. We investigated the release of inflammatory cytokine TNF-α from endothelial cells during AVF stenosis in Diabetes Mellitus, the mechanism of endothelial dysfunction, and the improvement of endothelial cell function to rescue of AVF stenosis after the implementation of interventions in clinical collected data, animal models, and cell-based studies. Our study finds high glucose stimulation could induce inflammatory cytokine TNF-α overproduction and dysfunction of endothelial cells. SMO expression was upregulated in high glucose stimulated endothelial cells, indicating activation of hedgehog signaling. Inhibition of SMO expression either by genetically knockdown or with its inhibitor Cyclopamine (Cyc) efficiently reduced the release of TNF-α and partially reverted the endothelial dysfunction in vitro and in vivo. GLI1 was further confirmed to be a downstream effector of SMO to induce the expression of TNF-α, and its inhibitor could block this effect. This study provides a new perspective that SMO-GLI1 axis as a promising therapeutic target for reducing the release of inflammatory cytokine TNF-α and alleviating endothelial cell dysfunction to prevent AVF stenosis in diabetic patients. Keywords: arteriovenous fistula stenosis; endothelial cell dysfunction; hedgehog signaling pathway; high glucose; inflammatory cytokine. Disclosures: No relevant conflicts of interest to declare. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Risk Factors of Arteriovenous Fistula Stenosis of Patients with Maintenance Hemodialysis.

To investigate the risk factors of arteriovenous fistula stenosis in maintenance hemodialysis patients. A total of 80 patients with maintenance hemodialysis in our hospital from January 2017 to January 2022 were included. According to the stenosis degree of the arteriovenous fistula, patients were divided into a stenosis group (n = 35) and an unobstructed group (n = 45). Laboratory examination data, such as the demographic characteristics of patients, past medical history, the use of traditional Chinese medicine (TCM), the TCM for improving blood circulation to promote blood circulation and remove blood stasis, and cellular immune function, were collected. Multivariate Logistic regression analysis was used to analyze the influencing factors. There was no significant difference in the age, sexuality, body mass index, proportion of patients with coronary heart disease, cephalic vein diameter, radial artery diameter, albumin, fibrinogen, and blood calcium levels between the two groups (P > 0.05). Compared with the unobstructed group, the stenosis group had higher rates of diabetes and hypertension as well as significantly higher levels of platelets, parathyroid hormone, and D-dimer (P < 0.05). The proportion of TCM application in the stenosis group was 28.6% (10/35), which was significantly lower than that in the unobstructed group 57.8% (26/45). The difference was statistically significant (χ 2 = 6.785, P=0.009). The levels of CD3+ (37.5 ± 5.1% vs. 42.0 ± 4.8%), CD4+ (35.7 ± 3.2% vs. 39.6 ± 3.1%) and CD4+/CD8+ (1.4 ± 0.3 vs. 2.4 ± 1.0) in the stenosis group were significantly lower, while CD8+ level was significantly higher (26.8 ± 5.1% vs. 18.5 ± 6.2%) than that in the unobstructed group (P < 0.001). Logistic regression analysis indicated that the usage of TCM was an independent risk factor for arteriovenous fistula stenosis after adjustment for other factors (odds ratio [OR] 0.302; 95% confidence interval [95% CI] 0.100-0.896; P=0.039). Less use of traditional Chinese medicine for activating blood circulation and removing blood stasis and poor cellular immune function are important factors affecting the function of the arteriovenous fistula in patients with maintenance hemodialysis, which is worthy of clinical attention.

Comparing non-invasive diagnostic methods for arteriovenous fistula stenosis: a prospective study.

International guidelines recommend screening for arteriovenous fistula (AVF) stenosis using various non-invasive methods. We evaluate different non-invasive AVF flow measurements for detecting AVF stenosis. Twenty-three haemodialysis patients with suspected AVF stenosis are enrolled based on abnormal physical signs or high venous pressure during dialysis. Ultrasound dilution, urea dilution, Doppler ultrasonography, and fistulography are performed on all patients. The accuracy of three non-invasive methods is compared. Fistulography reveals AVF stenosis in 18 patients, 12 of whom have severe stenosis (greater than 50% stenosis in diameter). Concerning the location of the stenosis lesions, eight are at the inflow site, six at the outflow site, and four on both sites. Receiver operating characteristic curve analysis shows that Doppler ultrasonography has a high discriminative ability and the averaged areas under the curves are 0.933 (95% confidence interval [CI]; 0.81 to 0.99) for stenosis and 0.929 (95% CI 0.82-0.99) for severe stenosis. The sensitivity of each method for the prediction of access stenosis using ultrasound dilution, urea dilution, and Doppler ultrasonography is 73%, 73%, and 80%, respectively. The respective specificity of each method is 40%, 80%, and 100%, respectively. Physical examination (PE) shows an 80% sensitivity and 80% specificity in the detection of AVF stenosis. The combination of Doppler ultrasound with PE produces the highest sensitivity (93%) for detecting AVF stenosis. Doppler ultrasound combined with physical examination is more accurate than other non-invasive methods for detecting AVF stenosis.

Surveillance and monitoring of early failing arteriovenous fistula using Doppler assessment in children on regular hemodialysis

BackgroundA well-functioning vascular access is a mainstay to perform an efficient hemodialysis procedure. Limited lifespan of arteriovenous accesses is one of the major challenges of the current long-term hemodialysis therapy. Vascular access-related morbidity accounts for up to 50% of total dialysis patient’s costs. The pediatric vascular access clinical guidelines published by the National Kidney Foundation Kidney Disease Outcome Quality Initiative recommend establishing a surveillance strategy to detect access stenosis and direct patients for early intervention. The aim of this study was to test the role of using the color Doppler ultrasonography (CDU) as a surveillance method for arteriovenous fistulae in children on regular hemodialysis and its value for detecting the early vascular access failure or dysfunction to avoid access loss.ResultsDuring 10-month duration, we prospectively conducted surveillance for 30 patients on regular hemodialysis through arteriovenous fistulae (AVF) as a vascular access, clinical assessment of AVF and radiological examination using CDU of the upper limbs. Their ages were ranging from 2 to 18 years with 1:1 male: female ratio. Doppler indices were measured in the afferent arteries, at the site of anastomosis, and the draining veins. AVF stenosis was the highest among all the detected complications (n = 9, 30%), aneurysm and pseudoaneurysmal formation (n = 8, 26%) anastomoses diameter reduction in 16.6%, and it was correlated with the dialysis adequacy measured through the Kt/v. Other complications were thrombosis (n = 2, 6.7%), central venous stenosis (n = 2, 6.7%), steal syndrome (n = 1, 3.3%) and calcifications in (n = 1, 3.3%). In total, 26% of the patients have more than one malfunction. Only one case has access failure a month after CDU examination.ConclusionIn conclusion, among pediatric patients CDU can detect early stenosis of AVF in children, which can affect the dialysis adequacy.

Pentoxifylline decreases the activity of the nucleotide-binding oligomerization domain-like receptor protein 3 pathway: potential role for preventing arteriovenous fistula stenosis.

This study aimed to determine the effect of pentoxifylline (PTX) on the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome pathway and its role in preventing arteriovenous fistula (AVF) failure. Vein samples were collected from AVF failure patients and from patients who underwent surgical AVF as a control. The expressions of CD34 and NLRP3 in AVF tissues were detected by immunohistochemistry and Western blotting. Arteriovenous fistula rat models were established by the end-to-end anastomosis of the common carotid artery and external jugular vein. The AVF models were divided into the following groups: AVF, AVF + PTX, AVF + uraemia and AVF + uraemia + PTX. Six weeks after surgery, the AVF tissues in each group were collected to detect the expressions of CD34, NLRP3, caspase-1 and interleukin (IL)-1β by immunohistochemistry, Western blotting and real-time polymerase chain reaction. The expressions of NLRP3 and CD34 in human AVF failure tissues were significantly higher than those in normal veins (p < 0.001), indicating that NLRP3 was upregulated in patients with AVF failure. In our animal study, the veins in the AVF + uraemia group exhibited heavy hyperplasia, and the boundary between the media and the adventitia was not clear. However, PTX alleviated this hyperplasia. Compared with the AVF models, the AVF + uraemia models had much higher expressions of NLRP3, caspase-1, IL-1β and CD34 (p < 0.001). However, PTX had the opposite effect against uraemia on the NLRP3 inflammasome pathway at both the gene and protein levels. Our findings provide new insights that show that PTX can decrease the activity of the NLRP3 inflammasome pathway in AVF models. Pentoxifylline has the potential as a drug for preventing intimal hyperplasia and AVF failure.