Monitoring the Patient Following Radio-Cephalic Arteriovenous Fistula Creation: Current Perspectives

Antiplatelet-anticoagulant, APAC, a mimic of endogenous heparin, is an antithrombotic with von Willebrand factor-mediated characteristics

BACKGROUND

We have conjugated selected number of unfractionated heparin (UFH) chains to human albumin core to mimic mast-cell heparin proteoglycans (HEP-PG). Indeed, APAC, dual antiplatelet and anticoagulant, as HEP-PG, has inhibited collagen- (CIPA) and thrombin-induced platelet aggregation, being simultaneously an anticoagulant. In several animal models of arterial thrombosis, APAC has provided vascular-injury-associated local antithrombotic properties mediated by von Willebrand factor (VWF).

AIMS

We compared the structure-function effects of APAC with those of UFH in vitro, and when supplemented in blood studied platelet and VWF-dependency and anticoagulation.

METHODS

We assessed the total thrombosis formation analysis system (T-TAS) and coagulation (rotational thromboelastometry, ROTEM) in blood, and thrombin generation and aggregation in platelet-rich plasma. We studied aggregation responses of APAC to collagen, ristocetin, ADP, and potential synergism with cangrelor, P2Y12 receptor antagonist. Finally, heparin-neutralizing role of platelet factor 4 (PF4) on antiplatelet and anticoagulant functions of APAC was investigated.

RESULTS

APAC concentration-dependently exceeded the anticoagulant and antithrombotic action of UFH in ROTEM, and platelet thrombus formation under arterial blood flow over collagen/tissue factor. APAC uniquely inhibited CIPA. While ADP- and ristocetin-induced aggregation were unaffected by APAC, we detected synergism with cangrelor for CIPA. Disruption of the tertiary structure of APAC reverted its mode of action to anticoagulation only, alike UFH. PF4 neutralized antithrombotic actions of APAC.

CONCLUSION

The structure-function of APAC conveys dual and unique antiplatelet and anticoagulant actions in flowing blood over collagen and beyond. Our studies confirmed the inhibitory role of APAC on VWF functions and fibrin formation.

Health-care Professionals' Perspectives on Ultrasound Evaluation of Arteriovenous Hemodialysis Fistula: A Narrative Review

Arteriovenous hemodialysis fistulas play a critical role in maintaining life on hemodialysis. With the growing use of Doppler ultrasound in nephrology, its utility has expanded to improve the prognosis and quality of life of patients receiving hemodialysis. On a fistula care team, different health-care professionals, including nephrologists, dialysis technicians, and surgeons or vascular interventionalists, require different information. This review article comprehensively explains how Doppler ultrasound evaluation can be beneficial in the management of arteriovenous fistulas from different perspectives of health-care professionals. The article also introduces the pathophysiology of arteriovenous fistula disease and provides a thorough introduction to the use of Doppler ultrasound for the evaluation of arteriovenous fistulas and their associated diseases, addressing the need for a comprehensive understanding among ultrasound practitioners.

Does the balloon-assisted maturation procedure offer comparable results for AVF created with a smaller vein?

BACKGROUND

Traditionally, a venous diameter of less than 3 mm was not considered for creation of AVF. Some studies have reported smaller venous size could be used for operation. AVF created with a smaller vein may have a lower maturation rate. Currently, percutaneous angioplasty is also used to enhance the maturation of AVF. This study aimed to establish whether the BAM procedure could offer comparable results for AVF created with a smaller vein.

METHODS

From January 2016 to July 2021, 290 patients who received native AVF operation were enrolled in this study. All of the preoperative venous sizes were measured by Duplex ultrasonography under tourniquet enhancement. The study cohort was categorized into two groups based on the pre-operative venous diameter: smaller vein group (SVG, 2.5 < size < 3 mm, 53.1%) and normal vein group (NVG, size ⩾ 3 mm, 46.9%).

RESULTS

The mean age was 64 ± 12.9 years, and 58.6% of patients were male. Hypertension and DM were the most common comorbidities. Most patients underwent operation of radio-cephalic fistula (71.4%). The overall primary maturation rate was 79%. The primary maturation rate was significantly higher in the NVG (86% vs 72.7%, p = 0.009). However, after the BAM procedure, the secondary maturation rate was similar in both groups (94.1% vs 90.3%, p = 0.319).

CONCLUSIONS

According to our study, the BAM procedure can significantly increase the maturation rate, and the secondary maturation rate was similar in both groups. Thus, more patients can be given the opportunity to undergo creation of an AVF for long-term hemodialysis.

Application of a supporting catheter in surgery for forearm arteriovenous fistula construction

INTRODUCTION

This study explored the feasibility of a supporting catheter combined with modified end-to-side anastomosis in the operation of radio-cephalic arteriovenous fistula (RC-AVF) and evaluated the clinical application value of this technique.

METHODS

Sixty patients underwent RC-AVF operations in our hospital from January 2022 to June 2022. All the patients were treated with modified end-to-side AVF anastomosis and divided into the control group or the test group depending on whether a supporting catheter was applied. The clinical data of 60 cases were analysed retrospectively. Intraoperative related indices, the first time the fistula was used, the success rate of first puncture, the blood flow of first dialysis, the maturity condition of fistula, the size of anastomosis, the diameter of radial artery and drainage vein, the blood flow of brachial artery 8 weeks after operation and the incidence of complications within 6 months after operation were compared between the two groups.

RESULTS

Compared with that in the control group, the time spent on the vascular anastomosis in the test group was significantly shortened (p<0.05). The blood flow of the first dialysis, the size of the anastomosis, the diameter of the drainage vein, the blood flow of the brachial artery 8 weeks after the operation and the incidence of complications within 6 months after operation were significantly different between the two groups (p<0.05).

CONCLUSION

In the RC-AVF operation, using a supporting catheter can not only increase operation efficiency by reducing surgical injury and difficulty of vascular anastomosis, but also improve postoperative prognosis. RC-AVF is worth promoting in clinical practice.

Sociodemographic Disparities in Adults with Kidney Failure: A Meta-Analysis

This meta-analysis aims to assess current evidence regarding sociodemographic disparities among adults with kidney failure. Medline, Scopus, Web of Science, CENTRAL, and Google Scholar were systematically searched from inception to 20 February 2022. Overall, 165 cohort studies were included. Compared to White patients, dialysis survival was significantly better among Black (hazard ratio-HR: 0.68; 95% CI: 0.61-0.75), Asian (HR: 0.67; 95% CI: 0.61-0.72) and Hispanic patients (HR: 0.80; 95% CI: 0.73-0.88). Black individuals were associated with lower rates of successful arteriovenous fistula use, peritoneal dialysis and kidney transplantation, as well as with worse graft survival. Overall survival was significantly better in females after kidney transplantation compared to males (HR: 0.87; 95% CI: 0.84-0.90). Female sex was linked to higher rates of central venous catheter use and a lower probability of kidney transplantation. Indices of low SES were associated with higher mortality risk (HR: 1.22, 95% CI: 1.14-1.31), reduced rates of dialysis with an arteriovenous fistula, peritoneal dialysis and kidney transplantation, as well as higher graft failure risk. In conclusion, Black, Asian and Hispanic patients present better survival in dialysis, while Black, female and socially deprived patients demonstrate lower rates of successful arteriovenous fistula use and limited access to kidney transplantation. PROSPERO registration: CRD42022300839.

Oscillometric pulse wave analysis for detecting low flow arteriovenous fistula

BACKGROUND

Pulse wave analysis may be useful to assess fistula function. We aimed to prospectively evaluate if convenient oscillometric devices are applicable to detect flow below 500 ml/min in a real life clinical setting.

METHODS

Pulse waves were recorded ambilaterally with the vicorder® device at the brachial artery in 53 patients on haemodialysis with native fistula. Primary variables consisted of the mean slope between the systolic maximum and the diacrotic notch (Slope2), the sum of the mean slopes in the four characteristic sections of pulse waves (Slope∑) and the amplitude of relative volumetric change in the measuring cuff at the upper arm (AMP). Fistula flow was measured with the use of duplex sonography using a standardized approach.

RESULTS

Parameter values above or below the median indicated measurement at the non-fistula side, with sensitivities/specificities of 0.79/0.79 (p < 0.001) for Slope 2, 0.64/0.64 (p = 0.003) for Slope∑ and 0.81/0.81 (p < 0.001) for AMP if measurements at the fistula and non-fistula arm were considered. ROC-analyses of parameter values measured at the fistula to detect low flow demonstrated AUCs (with CI) of 0.652 (0.437-0.866, p = 0.167) for Slope2, 0.732 (0.566-0.899, p = 0.006) for Slope∑ and 0.775 (0.56-0.991, p = 0.012) for AMP. The point with maximal youden's index was regarded as optimal cut-off, which corresponded to sensitivities and specificities of 0.8/0.56 for slope2, 0.86/ 0.56 for Slope∑ and 0.93/0.78 for AMP.

CONCLUSION

Functional surveillance with oscillometry is a promising clinical application to detect a low fistula flow. Among all investigated pulse wave parameters AMP revealed the highest diagnostic accuracy.

Heterogeneous Maturation of Arterio-Venous Fistulas and Loop-Shaped Venous Interposition Grafts: A Histological and 3D Flow Simulation Comparison

Vascular graft maturation is associated with blood flow characteristics, such as velocity, pressure, vorticity, and wall shear stress (WSS). Many studies examined these factors separately. We aimed to examine the remodeling of arterio-venous fistulas (AVFs) and loop-shaped venous interposition grafts, together with 3D flow simulation. Thirty male Wistar rats were randomly and equally divided into sham-operated, AVF, and loop-shaped venous graft (Loop) groups, using the femoral and superficial inferior epigastric vessels for anastomoses. Five weeks after surgery, the vessels were removed for histological evaluation, or plastic castings were made and scanned for 3D flow simulation. Remodeling of AVF and looped grafts was complete in 5 weeks. Histology showed heterogeneous morphology depending on the distribution of intraluminal pressure and WSS. In the Loop group, an asymmetrical WSS distribution coincided with the intima hyperplasia spots. The tunica media was enlarged only when both pressure and WSS were high. The 3D flow simulation correlated with the histological findings, identifying “hotspots” for intimal hyperplasia formation, suggesting a predictive value. These observations can be useful for microvascular research and for quality control in microsurgical training.

Uncommon Surgical Management by AVF between the Great Saphenous Vein and Anterior Tibial Artery for Old Radiocephalic AVF Failure

Introduction: Autologous native arteriovenous fistula (AVF) created in the non-dominant arm is the gold standard vascular access for dialysis in end-stage renal disease, but the post-surgical vascular access dysfunction causes a reduction in the patient’s quality of life. Creating a functional upper extremity permanent arteriovenous access is limited by the upper limb’s vascular resources, so good management of a complicated arteriovenous fistula may improve patient outcomes. This article highlights the importance of new surgical options in treating complicated AVFs. Case report: We present the case of a patient with a 17-year-old complex radio-cephalic arterio-venous fistula and a series of surgical interventions performed for life salvage in the first place and functional vascular access in the second place. Furthermore, we describe a successfully created uncommon type of fistula in the lower extremity between the great saphenous vein and the anterior tibial artery as the last possible access for hemodialysis in this patient. Results: The patient underwent the first successful dialysis using the newly created lower limb fistula 1 month after the surgery. Conclusion: Applying new surgical techniques to manage AVFs gives a unique chance to improve the quality of life and reduce morbidity and mortality in these patients.

Gender Disparities in Vascular Access and One-Year Mortality among Incident Hemodialysis Patients: An Epidemiological Study in Lazio Region, Italy

(1) Background: Interest in gender disparities in epidemiology, clinical features, prognosis and health care in chronic kidney disease patients is increasing. Aims of the study were to evaluate the association between gender and vascular access (arteriovenous fistula (AVF) or central venous catheter (CVC)) used at the start of hemodialysis (HD) and to investigate the association between gender and 1-year mortality. (2) Methods: The study includes 9068 adult chronic HD patients (64.7% males) registered in the Lazio Regional Dialysis Register (January 2008–December 2018). Multivariable logistic regression models were used to investigate the associations between gender and type of vascular access (AVF vs. CVC) and between gender and 1-year mortality. Interactions between gender and socio-demographic and clinical variables were tested adding the interaction terms in the final model. (3) Results: Females were older, had lower educational level and lower rate of self-sufficiency compared to males. Overall, CVC was used in 51.2% of patients. Females were less likely to use AVF for HD initiation than males. 1354 out of 8215 (16.5%) individuals died at the end of the follow-up period. Interaction term between gender and vascular access was significant in the adjusted model. From stratified analyses by vascular access, OR female vs. male (AVF) = 0.65; 95% CI 0.48–0.87 and OR female vs. male (CVC) = 0.88; 95% CI 0.75–1.04 were found. (4) Conclusions: This prospective population-based cohort study in a large Italian Region showed that in females starting chronic HD AVF was less common respect to men. The better 1-year survival of females is more evident among those women with AVF. Reducing gender disparity in access to AVF represents a key point in the management of HD patients.