Early follow-up results of arteriovenous fistulae created for hemodialysis

Prevalence of thrombosis in patients undergoing dialysis treatment: A systematic review and meta-analysis

AIM

to determine the prevalence of thrombosis in dialysis patients.

BACKGROUND

Thrombosis is the most common cause of vascular access dysfunction in dialysis patients. Various studies have reported different prevalence rates of thrombosis, and no systematic study provides a comprehensive result on this subject.

METHODS

In this systematic review and meta-analysis, a search of available texts was conducted until the end of December 2023, using keywords such as Thrombosis, end-stage renal disease, end-stage kidney disease, hemodialysis, and dialysis in databases including Web of Science, PubMed, Scopus, ProQuest, Ovid, Science Direct, Clinical Key, EMBASE, CINAHL, SID, and MagIran. The random-effects model was used, and the heterogeneity of the studies was assessed using the I2 index. The quality of the selected studies was evaluated using the STROBE checklist. Meta-analysis was performed using CMA version 2 and STATA version 14 software. The study adhered to the guidelines stated in the PRISMA statement.

RESULTS

Out of 12,604 articles found, after removing duplicates and conducting evaluations, the full text of 415 articles was examined, and ultimately, 141 articles were included in the study. The overall prevalence of thrombosis was 14.2% (95% CI: 11.5-17.2). The prevalence of thrombosis was higher in dialysis patients under 50 years of age (17.1%, 95% CI: 11.3-23.8) and patients with vascular access (16.2%, 95% CI: 13.1-19.5), especially arteriovenous grafts (22.8%, 95% CI: 14.5-32.4). Additionally, the prevalence of late thrombosis was higher than that of early thrombosis (15.0% vs. 5.3%) (95% CI: 7.7-24.2 vs. 95% CI: 2.7-8.5).

CONCLUSIONS

The results indicate a relatively high prevalence of thrombosis in dialysis patients. The prevalence of thrombosis in patients with arteriovenous grafts was notable. Considering the risks of thrombosis, the adoption of preventive measures in hemodialysis patients, such as the use of anticoagulant drugs, is recommended.

Cathepsin G promotes arteriovenous fistula maturation by positively regulating the MMP2/MMP9 pathway

BACKGROUND

Arteriovenous fistula (AVF) is currently the preferred vascular access for hemodialysis patients. However, the low maturation rate of AVF severely affects its use in patients. A more comprehensive understanding and study of the mechanisms of AVF maturation is urgently needed.

METHODS AND RESULTS

In this study, we downloaded the publicly available datasets (GSE119296 and GSE220796) from the Gene Expression Omnibus (GEO) and merged them for subsequent analysis. We screened 84 differentially expressed genes (DEGs) and performed the functional enrichment analysis. Next, we integrated the results obtained from the degree algorithm provided by the Cytohubba plug-in, Molecular complex detection (MCODE) plug-in, weighted gene correlation network analysis (WGCNA), and Least absolute shrinkage and selection operator (LASSO) logistic regression. This integration allowed us to identify CTSG as a hub gene associated with AVF maturation. Through the literature search and Pearson's correlation analysis, the genes matrix metalloproteinase 2 (MMP2) and MMP9 were identified as potential downstream effectors of CTSG. We then collected three immature clinical AVF vein samples and three mature samples and validated the expression of CTSG using immunohistochemistry (IHC) and double-immunofluorescence staining. The IHC results demonstrated a significant decrease in CTSG expression levels in the immature AVF vein samples compared to the mature samples. The results of double-immunofluorescence staining revealed that CTSG was expressed in both the intima and media of AVF veins. Moreover, the expression of CTSG in vascular smooth muscle cells (VSMCs) was significantly higher in the mature samples compared to the immature samples. The results of Masson's trichrome and collagen I IHC staining demonstrated a higher extent of collagen deposition in the media of immature AVF veins compared to the mature. By constructing an in vitro CTSG overexpression model in VSMCs, we found that CTSG upregulated the expression of MMP2 and MMP9 while downregulating the expression of collagen I and collagen III. Furthermore, CTSG was found to inhibit VSMC migration.

CONCLUSIONS

CTSG may promote AVF maturation by stimulating the secretion of MMP2 and MMP9 from VSMCs and reducing the extent of medial fibrosis in AVF veins by inhibiting the secretion of collagen I and collagen III.

Sex disparities in hemodialysis access outcomes: A systematic review

The goal of this systematic review was to collate and summarize the current literature on hemodialysis access outcomes in females, identify differences between females and men, and provide a foundation for future research. A systematic review of the English-language literature was conducted by searching PubMed and Google Scholar for the following terms: "sex," "hemodialysis access," "arteriovenous fistula," "arteriovenous graft," and "dialysis catheter." Reference lists from the resulting articles were also evaluated to ensure that any and all relevant primary sources were identified. Studies were then screened by two independent reviewers for inclusion. Of 967 total studies, 53 ultimately met inclusion criteria. Females have lower maturation rates; have decreased rates of primary, primary-assisted, and secondary patency; require more procedures per capita to achieve maturation and to maintain fistula patency; are more likely to receive dialysis via an arteriovenous graft or central venous catheter; and require a longer time and potentially more assistive invasive interventions to achieve a mature fistula. Our findings emphasize the urgent need for further research to evaluate and address the causes of these disparities. Discussion with patients undergoing hemodialysis should include these findings to improve patient education, expectations, satisfaction, and outcomes.

Oversized balloon angioplasty for endovascular maturation of arteriovenous fistulae to accelerate cannulation and to decrease the duration of catheter use

BACKGROUND

The functional autologous arteriovenous fistula is considered the best vascular access for patients on hemodialysis. Some fistulae exhibit maturation problems after creation and do not reach adequate vessel diameter and flow in dialysis. The aim of this study was to describe our technique of oversized balloon angioplasty for assisted maturation of arteriovenous fistulae to accelerate the cannulation and to decrease the time of catheter use and its outcome.

METHODS

A retrospective analysis of balloon-assisted procedures for maturation failure was performed in a single center between October 2011 and January 2019. Patients underwent imaging procedures to identify stenosis, followed by angioplasty using oversized high-pressure balloons from the anastomosis to the deep venous outflow tract. The flow volume, time interval of use of the fistula and removal of the catheter, patency rates, and complications rates were evaluated.

RESULTS

Seventy-eight patients underwent 124 balloon angioplasty procedures. Technical and clinical success was achieved in 91% of the cases. In patients in whom maturation was successful, the fistula was cannulated in a mean time of 5 days after the procedure (range, 1-20 days). On average, catheter removal was performed 14 days (range, 5-33 days) after the maturation procedure. The mean flow volume in the fistula before the procedure was 276 ml/min (range, 122-488 ml/min) and 24 h after the maturation was 1014 ml/min (range, 760-1800 ml/min).The primary patency rate at 3, 6, and 12 months was 87.3%, 66.2%, and 50.7%, respectively. Assisted primary patency was 100% at 3 months, 92.9% at 6 months, and 90.0% at 12 months. Minor complications occurred in 18% of cases, and major complications in 4.8%.

CONCLUSIONS

The oversized balloon-assisted arteriovenous fistula maturation technique is safe and effective, allowing the cannulation of the fistulae a few hours or days after the procedure and decreasing the time of catheter use.

Evaluation of Factors Affecting Wrist Radio-Cephalic Arteriovenous Fistula Maturation: A Single Institutional Observational Study

Background: Chronic renal failure is the most common indication for which arterio-venous (AV) fistula creation surgery is being performed. Various studies have found that native arteriovenous fistulas are the best in long-term patency with lower complications. We conducted this study to find out the role of preprocedural duplex ultrasound (DUS) in predicting outcomes of radio-cephalic fistula in the wrist in the North-Karnataka population. Methods: This prospective study was conducted from May 2019 to July 2020 on 50 patients who were hemodialysis-dependent and underwent AV fistula creation with age from 20 to 70 years. All the patients underwent preoperative DUS and were followed up post-operatively after one, two, and six weeks. Hemodialysis was initiated through the constructed fistula once it was mature, and the maximum blood flow through the fistula was measured. SPSS version 20.0 was used for statistical analysis. Results: Among 50 subjects, the overall cumulative success of AVF maturation was 86% (43), and failure to mature rate was 14% (7). Logistic regression of maturation outcome in the wrist autologous arteriovenous fistula for individual factors showed statistically significant results (P < 0.05) for the diameter of the radial artery > 1.6 mm and the distensibility of the cephalic vein > 0.4 mm. Conclusions: Vein distensibility and radial artery diameter are key factors in predicting successful AVF maturation. The use of intraoperative papaverine instillation directly on vessels can improve arteriovenous fistula outcomes.

Effect of local papaverine on arteriovenous fistula maturation in patients with end-stage renal disease

BACKGROUND

Arteriovenous fistula (AVF) maturation is one of the main concerns in patients with end-stage renal disease (ESRD) and finding a strategy for increasing success rate and accelerating fistula maturation is valuable. The aim of this study was to evaluate the effects of papaverine injection on AVF maturation and success rate.

METHOD

This study was a randomized clinical trial that involved 110 patients with ESRD that were referred for AVF construction. Patients were allocated in papaverine group and control group with block randomization according to age and sex. In the case group, papaverine (0.1 or 0.2 cc) was injected locally within the subadventitia of artery and vein after proximal and distal control during AVF construction and in the control group, AVF construction was done routinely without papaverine injection.

RESULTS

Maturation time in case and control groups was 37.94 ± 11.49 and 44.23 ± 9.57 days, respectively (p=0.004). Hematoma was not seen in the case group but occurred in one patient in the control group. One patient of the case group developed venous hypertension. Four functional fistulas, 1 (1.8%) in the case group and 3 (5.5%) in the control group, failed to mature (p=0.618). Maturation rate did not differ between the two groups statistically (p=0.101).

CONCLUSION

Local papaverine injection increased vessel diameter and blood flow, increasing shearing stress in both arterial and venous segment of recently created AVF. In this way, papaverine probably can decrease AVF maturation time without an increase in complications.

Predictive parameters of arteriovenous fistula maturation in patients with end-stage renal disease

Background

The objevctive of the present study was to explore the potential influence of blood markers and patient factors such as risk factors, kidney function profile, coagulation profile, lipid profile, body mass index, blood pressure, and vein diameter on the maturation of arteriovenous fistula (AVF) in patients with end-stage renal disease.

Methods

Retrospective data from 300 patients who had undergone AVF creation at the Royal Infirmary of Edinburgh were examined. A predictive logistic regression model was developed using a backward stepwise procedure. Model performance, discrimination, and calibration were assessed using the receiver operating characteristic (ROC) curve and Hosmer–Lemeshow goodness-of-fit test. The final model was externally validated by 100 prospective patients who received a new fistula at the Royal Infirmary of Edinburgh.

Results

A total of 400 (300 retrospective and 100 prospective) patients were recruited for this study, with a mean age of 60.14 ± 15.9 years (development set) and 58 ± 15 years (validation set), respectively (P = 0.208). Study results showed that males were twice as likely to undergo fistula maturation as females, while patients with no evidence of peripheral vascular disease (PVD) were three times more likely to mature their fistula and a preoperative vein diameter > 2.5 mm resulted in a fivefold increase in fistula maturation as compared with a vein size of less than 2.5 mm. The model for fistula maturation had fair discrimination, as indicated by the area under the ROC curve (0.68), but good calibration as indicated by the Hosmer–Lemeshow test (P = 0.79). The area under the receiver operating curve for the validation model in the validation set was 0.59. Similarly, in the validation set, the Hosmer–Lemeshow statistic indicated an agreement between the observed and predicted probabilities of maturation (P > 0.05).

Conclusion

Gender, PVD, and vein size are independent predictors of AVF maturation. The clinical utility of these risk categories in the maturation of AVF requires further evaluation in longer follow-up.

Distal-to-Snuffbox Arteriovenous Fistula

The dogma for optimal arteriovenous fistula (AVF) creation is based on starting as distally as possible on the upper limb and progressing proximally. We herein present our findings of an AVF that is as distal as possible on the hand. To document primary patency rates of the distal-to-snuffbox AVF. A 10-year prospective study (2006-2016) involving 31 patients whose distal cephalic vein diameter was ≥3 mm with a normal Allen's test was conducted. Patients were excluded if the radial artery in the wrist was highly calcified, the cephalic vein did not dilate more than 3 mm with proximal compression, and there was previously failed AVF of the limb or previous trauma to the limb. The procedure was performed under local anesthetic, and the anastomosis performed with a 6.0 polypropylene suture in an end-to-side fashion. Thirty-one patients with end-stage renal disease underwent distal vascular access using the distal-to-snuffbox (Hitchhiker's) AVF (HAVF). During follow-up, eight patients died with an adequately functioning HAVF. The primary patency rates at 12, 24, 48, and 60 months were 90, 87, 85, and 82%, respectively. Failure occurred in six (19%) cases over the follow-up period, two in the first 2 weeks and four over a span of 60 months. Conclusion  The creation of radiocephalic AVFs in the first web space, distal to the tendon of the extensor pollicis longus, serves as a viable option with acceptable success rates. This allows the surgeon more options with proper patient selection for this procedure.

Radiocephalic fistulas for hemodialysis: a comparison of techniques

The radiocephalic fistula dates back to the 1960s with good long-term survival and a low incidence of complications. The standard practice of creating an end cephalic vein to side radial artery fistula (ETS) has a high incidence of early thrombosis and failure to mature, which limits its efficacy. The hypothesis is that a 1.3- to 1.5-cm side-to-side with distal vein ligation anastomosis (STS) is associated with a lower early thrombosis rate and higher primary patency rate. We retrospectively evaluated all radiocephalic fistulas created at our hospital from January 1, 2012, to December 31, 2012, comparing a 1.3- to 1.5-cm STS anastomosis to the ETS anastomosis. Primary endpoints were patency at three and six months and the secondary outcome was suitability for cannulation. An ETS anastomosis resulted in an early thrombosis rate, 3-month cannulation rate, and 6-month primary patency rate of 14, 30, and 48 per cent, respectively. Outcomes from the STS technique were significantly improved with no early thrombosis (P < 0.05), 3-month cannulation rate of 67 per cent (P < 0.03), and a primary patency of 75 per cent (P = 0.03). A STS radiocephalic fistula with distal vein ligation is superior to the ETS radiocephalic fistula. Early thrombosis, 6-month primary patency, and cannulation rates were significantly improved.

Intraoperative assessment of vascular access

PURPOSE

The intraoperative quality assessment of the arteriovenous fistula for hemodialysis is an essential process to limit early failure due to technical problems or inadequate vascular quality. This step is not clearly defined in the literature with no recommendations.

METHODS

We selected published articles related to the topic of intraoperative quality control of the vascular access for hemodialysis.

RESULTS

The intraoperative blood flow measurement greater than 120 ml/min in autologous fistula and less than 320 ml/min in arteriovenous graft was described as predictive factors for early failure.

CONCLUSIONS

The blood flow measurement should be performed after the confection of the anastomosis. When blood flow is limited, fistulography is an essential step to assess patency.