Impact of arteriovenous fistula blood flow on serum il-6, cardiovascular events and death: An ambispective cohort analysis of 64 Chinese hemodialysis patients

Estimating the association between systemic Interleukin-6 and mortality in the dialysis population. Re-analysis of the global fluid study, systematic review and meta-analysis

BACKGROUND

Systemic inflammation, measured as circulating Interleukin-6 (IL-6) levels, is associated with cardiovascular and all-cause mortality in chronic kidney disease. However, this has not been convincingly demonstrated in a systematic review or a meta-analysis in the dialysis population. We provide such evidence, including a re-analysis of the GLOBAL Fluid Study.

METHODS

Mortality in the GLOBAL fluid study was re-analysed using Cox proportional hazards regression with IL-6 levels as a covariate using a continuous non-logarithmic scale. Literature searches of the association of IL-6 levels with mortality were conducted on MEDLINE, EMBASE, PyschINFO and CENTRAL. All studies were assessed for risk of bias using the QUIPS tool. To calculate a pooled effect size, studies were grouped by use of IL-6 scale and included in the meta-analysis if IL-6 was analysed as a continuous linear covariate, either per unit or per 10 pg/ml, in both unadjusted or adjusted for other patient characteristics (e.g. age, comorbidity) models. Funnel plot was used to identify potential publication bias.

RESULTS

Of 1886 citations identified from the electronic search, 60 were included in the qualitative analyses, and 12 had sufficient information to proceed to meta-analysis after full paper screening. Random effects meta-analysis of 11 articles yielded a pooled hazard ratio (HR) per pg/ml of 1.03, (95% CI 1.01, 1.03), [Formula: see text]= 81%. When the analysis was confined to seven articles reporting a non-adjusted HR the result was similar: 1.03, per pg/ml (95% CI: 1.03, 1.06), [Formula: see text]=92%. Most of the heterogeneity could be attributed to three of the included studies. Publication bias could not be determined due to the limited number of studies.

CONCLUSION

This systematic review confirms the adverse association between systemic IL-6 levels and survival in people treated with dialysis. The heterogeneity that we observed may reflect differences in study case mix.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO - CRD42020214198.

Association between preoperative C-reactive protein to albumin ratio and late arteriovenous fistula dysfunction in hemodialysis patients: a cohort study

Arteriovenous fistula (AVF) dysfunction is a critical complication in hemodialysis (HD) patients, with inflammation potentially contributing to its development. This retrospective cohort study aimed to investigate the association between preoperative C-reactive protein to albumin ratio (CAR) and AVF dysfunction in Chinese HD patients. A total of 726 adults with end-stage renal disease who underwent new AVF placement between 2011 and 2019 were included. Multivariable Cox regression and Fine and Gray competing risk models were employed to assess the relationship between CAR and AVF dysfunction, considering death and renal transplantation as competing risks. Among 726 HD patients, 29.2% experienced AVF dysfunction during a median follow-up of 36 months. Adjusted analyses revealed that higher CAR levels were associated with an increased risk of AVF dysfunction, with a 27% higher risk per one-unit increase in CAR. Furthermore, patients with CAR values ≥ 0.153 exhibited a 75% elevated risk compared to those with CAR values < 0.035 (P = 0.004). The relationship between CAR and AVF dysfunction varied by the site of internal jugular vein catheter placement (P for trend = 0.011). Notably, the Fine and Gray analysis confirmed the association between CAR and AVF dysfunction, with a 31% increased risk per one-unit increase in CAR. The highest CAR tertile remained an independent predictor of AVF dysfunction (HR = 1.77, 95% CI 1.21-2.58, P = 0.003). These findings highlight the potential of CAR as a prognostic marker for AVF dysfunction in Chinese HD patients. Clinicians should consider CAR levels and catheter placement site when assessing the risk of AVF dysfunction in this population.

A family-centred perspective on the arteriovenous fistula in end-stage renal disease: Findings from dyadic interviews

INTRODUCTION

The preservation of a well-functioning arteriovenous fistula (AVF) is crucial for successful dialysis in patients with end-stage renal disease (ESRD); nonetheless, complications are frequent which leads to lower quality of life, hospitalisations and death. Self-care behaviours help to reduce the risk of complications and family caregivers can play an important role as partners for behaviour change. However, the patient and family caregiver's experiences with such an invasive intervention are largely unknown.

AIMS

This study aimed to explore the experiences of patients with ESRD and their family caregivers with the AVF through joint interviews.

METHODS

A qualitative exploratory study was conducted with a purposive sample. Semi-structured joint interviews were conducted with 14 dyads (28 participants) composed of patients on haemodialysis with AVF and their respective family caregivers. Interviews were audiotaped, transcribed verbatim and submitted to thematic analysis.

FINDINGS

Four major themes were identified: (i) AVF negative impacts; (ii) (un)presence of self-care behaviours; (iii) AVF self-management facilitators and (iv) AVF self-management barriers.

DISCUSSION

The findings suggested that more attention needs to be paid to patients' and their family caregivers' support needs (e.g. fears, concerns, knowledge, adherence barriers and facilitators) regarding AVF self-management. The dyads seem to be aware of how to take care of the AVF; however, self-care behaviours still need to be improved.

CONCLUSION

Innovative interventions need to follow an interdisciplinary approach with an educational and support component. The integration of family caregivers should also be considered, since this study evidenced their lack of knowledge and skills, and willingness to participate in these initiatives.

Association between Preoperative Monocyte-to-Lymphocyte Ratio and Late Arteriovenous Fistula Dysfunction in Hemodialysis Patients: A Cohort Study

BACKGROUND

Inflammation appears to be at the biological core of arteriovenous fistula (AVF) dysfunction, and the occurrence of AVF dysfunction is related to high death and disability in hemodialysis (HD) patients. Despite several studies on the correlations between AVF dysfunction and inflammatory indicators, how AVF dysfunction is related to the monocyte-to-lymphocyte ratio (MLR) is much unclear. We hypothesize that preoperative MLR is associated with AVF dysfunction in Chinese HD patients.

METHODS

In this single-center retrospective cohort study, totally 769 adult HD patients with a new AVF created between 2011 and 2019 were included. Association of preoperative MLR with AVF dysfunction (thrombosis or decrease of normal vessel diameter by >50%, requiring either surgical revision or percutaneous transluminal angioplasty) was assessed by multivariable Cox proportional hazard regression.

RESULTS

The patients were aged 55.8 ± 12.2 years and were mostly males (55%). During the average 32-month follow-up (maximum 119 months), 223 (29.0%) patients had permanent vascular access dysfunction. In adjusted multivariable Cox proportional hazard regression analyses, the risk of AVF dysfunction was 4.32 times higher with 1 unit increase in MLR (hazard ratio [HR]: 5.32; 95% confidence interval [CI]: 3.1-9.11). Compared with patients with MLR <0.28, HRs associated with an MLR of 0.28-0.41 and ≥0.41 are 1.54 (95% CI: 1.02-2.32) and 3.17 (2.18-4.62), respectively.

CONCLUSIONS

A higher preoperative MLR is independently connected with a severer risk of AVF dysfunction in HD patients. Its clinical value should be determined in the future.

Computational modeling of the cephalic arch predicts hemodynamic profiles in patients with brachiocephalic fistula access receiving hemodialysis

Background

The most common configuration for arteriovenous fistula is brachiocephalic which often develop cephalic arch stenosis leading to the need for numerous procedures to maintain access patency. The hemodynamics that contributes to the development of cephalic arch stenosis is incompletely understood given the inability to accurately determine shear stress in the cephalic arch. In the current investigation our aim was to determine pressure, velocity and wall shear stress profiles in the cephalic arch in 3D using computational modeling as tools to understand stenosis.

Methods

Five subjects with brachiocephalic fistula access had protocol labs, Doppler, venogram and intravascular ultrasound imaging performed at 3 and 12 months. 3D reconstructions of the cephalic arch were generated by combining intravascular ultrasounds and venograms. Standard finite element analysis software was used to simulate time dependent blood flow in the cephalic arch with velocity, pressure and wall shear stress profiles generated.

Results

Our models generated from imaging and flow measurements at 3 and 12 months offer snapshots of the patient’s cephalic arch at a precise time point, although the remodeling of the vessel downstream of an arteriovenous fistula in patients undergoing regular dialysis is a dynamic process that persists over long periods of time (~ 5 years). The velocity and pressure increase at the cephalic bend cause abnormal hemodynamics most prominent along the inner wall of the terminal cephalic arch. The topology of the cephalic arch is highly variable between subjects and predictive of pathologic stenosis at later time points.

Conclusions

Low flow velocity and wall pressure along the inner wall of the bend may provide possible nidus of endothelial activation that leads to stenosis and thrombosis. In addition, 3D modelling of the arch can indicate areas of stenosis that may be missed by venograms alone. Computational modeling reconstructed from 3D radiologic imaging and Doppler flow provides important insights into the hemodynamics of blood flow in arteriovenous fistula. This technique could be used in future studies to determine optimal flow to prevent endothelial damage for patients with arteriovenous fistula access.

Factors affecting arteriovenous fistula dysfunction: A narrative review

Vascular access dysfunction is one of the most important causes of morbidity and mortality in haemodialysis patients, contributing to up to one third of hospitalisations and accounting for a significant amount of the health care costs of these patients. In the past decades, significant scientific advances in understanding mechanisms of arteriovenous fistula maturation and failure have contributed to an increase in the amount of research into techniques for creation and strategies for arteriovenous fistula dysfunction prevention and treatment, in order to improve patient care and outcomes. The aim of this review is to describe the pathogenesis of vascular access failure and provide a comprehensive analysis of the associated risk factors and causes of vascular access failure, in order to interpret possible future therapeutic approaches. Arteriovenous fistula failure is a multifactorial process resulting from the combination of upstream and downstream events with consequent venous neo-intimal hyperplasia and/or inadequate outward remodelling. Inflammation appears to be central in the biology of arteriovenous fistula dysfunction but important triggers still need to be revealed. Given the significant association of arteriovenous fistula failure and patient's prognosis, it is therefore imperative to further research in this area in order to improve prevention, surveillance and treatment, and ultimately patient care and outcomes.

Dry-weight reduction improves intradialytic hypertension only in patients with high predialytic blood pressure

BACKGROUND

The aim of this study was to investigate whether additional volume reduction by ultrafiltration can improve blood pressure in patients with intradialytic hypertension (IDH) defined as at least 10 mmHg systolic blood pressure (SBP) rise during hemodialysis.

PATIENTS AND METHODS

This prospective, open-label, single-center study included 11 IDH patients with normal predialytic blood pressure (BP) (group A), 11 IDH patients with high predialytic BP (group B), and 18 patients without IDH as control. Serum angiotensin-II, aldosterone (ALD), angiotensin-converting enzyme, endothelin-1, nitric oxide, and asymmetric dimethylarginine were measured before and after the treatments.

RESULTS

Basic angiotensin-converting enzyme, ALD, endothelin-1, and asymmetric dimethylarginine serum levels were significantly increased in group B compared with control (P < 0.05). On comparing the results from the first and 13th dialysis sessions in group A, the dry weight was reduced by - 0.15 ± 0.16 kg after 12 sessions and the predialytic SBP increased by 3.18 ± 6.25 mmHg before and by 7.37 ± 14.90 mmHg at 4 h during the 13th session. In group B, the dry weight was reduced by 0.67 ± 0.53 kg (P = 0.006 vs. group A) at the 13th session and they had - 12.09 ± 16.20 mmHg less SBP before (P = 0.009 vs. group A) and - 11.82 ± 14.66 mmHg at 4 h of the 13th session. The decrease in dry weight was associated with significantly higher decreases in angiotensin-II and ALD serum levels in group B compared with group A.

CONCLUSION

Reducing fluid overload in IDH patients with high predialytic BP can effectively improve their BP, but had no effect on BP in normal predialytic BP IDH cases.