Can a Neutrophil–Lymphocyte Ratio Derived from Preoperative Blood Tests Predict Arteriovenous Fistula Maturation?

Association of neutrophil-to-lymphocyte ratio and hemodialysis access failure in patients with end stage renal disease: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to assess the association of neutrophil-to-lymphocyte ratio (NLR) with an elevated risk of vascular access failure in end-stage renal disease (ESRD) patients undergoing hemodialysis. A comprehensive database search of MEDLINE (via PubMed), Scopus, and Cochrane Central was performed. Studies reporting the values of NLR in both functional and non-functional AVF groups in ESRD patients were selected. Quality assessment was performed using the Modified Newcastle-Ottawa scale for observational studies. Meta-analysis was performed using an inverse variance random effects model. Seven observational studies met the inclusion criteria, including 1313 participants with 554 cases and 759 controls. Pooled results showed significantly high NLR levels in patients with non-functional arteriovenous fistula (AVF) compared to functional AVF (SMD = 1.19, 95% CI = 0.74-1.65, p < 0.001). Subgroup analysis confirmed the consistency of the association between NLR and AVF failure across study design (SMD = 1.76, 95% CI = 0.78-2.73, p = 0.0004 in prospective vs SMD = 0.87, 95% CI = 0.42-1.32, p = 0.0001 in retrospective studies), etiology (SMD = 1.63, 95% CI = 0.75-2.52, p = 0.0003 in stenosis or thrombosis; and SMD = 0.80, 95% CI = 0.27-1.34, p = 0.003 in failure to mature of AVF), and NLR measurement timing (SMD = 0.98, 95% CI = 0.42-1.54, p = 0.0006 in preoperative vs SMD = 1.58, 95% CI = 0.47-2.69, p = 0.005 in postoperative NLR). The pooled odds ratio revealed high NLR values as a significant predictor of AVF failure in ESRD patients (OR = 3.91, 95% CI = 1.91-7.98, p = 0.0002). The pooled sensitivity and specificity were 89.72% (95% CI = 77.51%-95.67%) and 72.95% (95% CI = 63.82%-80.47%), respectively. The high NLR is a useful and predictive marker for AVF failure in hemodialysis patients. Future studies should prioritize larger cohort studies to validate and reinforce these observations.

Regulation of vascular remodeling by immune microenvironment after the establishment of autologous arteriovenous fistula in ESRD patients

Autogenous arteriovenous fistula (AVF) is the preferred dialysis access for receiving hemodialysis treatment in end-stage renal disease patients. After AVF is established, vascular remodeling occurs in order to adapt to hemodynamic changes. Uremia toxins, surgical injury, blood flow changes and other factors can induce inflammatory response, immune microenvironment changes, and play an important role in the maintenance of AVF vascular remodeling. This process involves the infiltration of pro-inflammatory and anti-inflammatory immune cells and the secretion of cytokines. Pro-inflammatory and anti-inflammatory immune cells include neutrophil (NEUT), dendritic cell (DC), T lymphocyte, macrophage (Mφ), etc. This article reviews the latest research progress and focuses on the role of immune microenvironment changes in vascular remodeling of AVF, in order to provide a new theoretical basis for the prevention and treatment of AVF failure.

Systemic inflammation index as useful tool to predict arteriovenous graft stenosis: Our experience and literature review

OBJECTIVE

Many studies show that settings of severe inflammatory stress might be responsible for changes in circulating blood cells count. Effective inflammation indices are created calculating the quantitative relationship between these cells. No previous studies have been proposed on hemodialysis patients exploring the association between arteriovenous graft (AVG) stenosis and systemic inflammation markers, such as Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic-immune-inflammation index (SII).

METHODS

Patients undergone surgery for AVG creation in a 2-year period are examined. Examining their full blood count, we have established the value of inflammatory indices (NLR, PLR, SII) and we have compared their mean values in patients who have developed significant stenosis or not. Finally, we have considered the connection between those values and stenosis onset and recurrence in AVG.

RESULTS

Fifty-two patients are included in the study [male: 40%, mean age 70 ± 15 years (range 55-86)]. We have found out there is not statistical significance in preoperative values of inflammatory index (NLR p 0.33, PLR p 0.15, SII p 0.98) Otherwise NLR and SII indices were statistically significant 3 months after surgery (NLR 2.04 ± 0.98 vs 3.91 ± 2.10, p < 0.001; SII 415.32 ± 255.15 vs 636.91 ± 349.01, p 0.014).

CONCLUSIONS

Increased post-operative values of NLR and SII have proved a strong association with AVG outflow stenosis onset and recurrence.

Progress in the application of the neutrophil-to-lymphocyte ratio in dialysis-related complications

The neutrophil-to-lymphocyte ratio (NLR) is a novel predictive biomarker that reflects systemic inflammatory status and is routinely measured in blood tests. Owing to its ease of use and affordability, it is being increasing used as a prognostic indicator of cardiovascular disease, tumors, autoimmune disorders, and kidney disease. In recent years, a number of studies have demonstrated the clinical utility of the NLR in identifying and predicting complications associated with hemodialysis and peritoneal dialysis, including cardiovascular disease and infection. This review aimed to provide a new perspective on the application of the NLR as a valuable tool enabling clinicians to better assess the occurrence and prognosis of complications in patients undergoing dialysis.

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.

High Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratios Are Associated with a Higher Risk of Hemodialysis Vascular Access Failure

Our aim was to determine the predictive role of the preoperative neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in vascular access malfunctioning in patients who had undergone their first native arterio-venous fistula (AVF) for hemodialysis. Methods: This was a single-center retrospective observational study. All patients who underwent the procedure of the creation of a first native AVF for hemodialysis from January 2019 to December 2020 were considered eligible to be part of this study. Reinterventions for AVF malfunctioning were registered and the population was subdivided into two groups with respect to AVF malfunctioning. ROC curves were obtained to find the appropriate cut-off values for the NLR and PLR. A multivariate analysis was used to identify the independent predictors for an AVF malfunction. Kaplan−Meier curves were used to evaluate the AVF patency rates. A total of 178 patients were enrolled in the study, of them 70% (n = 121) were male. The mean age was 67.5 ± 12 years. Reinterventions for AVF malfunctioning were performed on 102 patients (57.3%). An NLR > 4.21 and a PLR > 208.8 was selected as the cut-off for AVF malfunctioning. The study population was divided into two groups depending on the NLR and PLR values of the individual. For the NLR < 4.21 group, the AVF patency rates were 90.7%, 85.3%, and 84% at the 3-, 6-, and 12-month follow-up, respectively, and 77.5%, 65.8%, and 39.3% at 3, 6, and 12 months for the NLR > 4.21 group, respectively (p < 0.0001). For the PLR < 208.8 group, the patency rates were 85.6%, 76.7%, and 67.7% at the 3-, 6-, and 12-month follow-up. For the PLR > 208.28 group, the patency rates were 80.8%, 71.2%, and 50.7% for the 3-, 6-, and 12-month follow-up, respectively (p = 0.014). The multivariate analysis highlighted that diabetes mellitus, the neutrophil count, the lymphocyte count, and the NLR were independent risk factors for an AVF failure. In our experience, the NLR and PLR are useful markers for the stratification of vascular access failure in hemodialysis patients. The inexpensive nature and ready availability of the values of these biomarkers are two points of strength for everyday clinical practice.

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.

Predictive value of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for primary patency of percutaneous transluminal angioplasty in hemodialysis arteriovenous fistula stenosis

OBJECTIVE

The aim of this study is to investigate the potential association of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with the primary patency of percutaneous transluminal angioplasty (PTA) in hemodialysis arteriovenous fistula (AVF) stenosis.

METHODS

This study conducted a retrospective review of patients with end-stage renal disease referred for hemodialysis AVF stenosis in one center. The study consisted of 114 patients with significant (significant stenosis was defined as a reduction in the caliber of the fistula vein of > 50% with respect to the non-aneurysmal venous segment). AVF stenosis patients were treated with PTA, with conventional balloon angioplasty. The NLR and PLR were calculated from the pre-interventional blood samples. The patients were classified into two groups: group A, primary patency < 12 months (n = 35) and group B, and primary patency ≥ 12 months (n = 79). Comparisons between the groups were performed using the Mann-Whitney U test. Kaplan-Meier analysis was performed to compare the factors, NLR and PLR, for association with primary patency AVFs. A receiver-operating characteristic curve analysis was performed to identify the sensitivity and specificity of the NLR and PLR cut-off values in the prediction of primary patency time.

RESULTS

There was no difference in gender; age; side of AVF; AVF type; comorbid diseases such as diabetes mellitus and hypertension; or blood parameters such as white cell count, erythrocytes, hemoglobin, neutrophils, lymphocytes, monocytes, eosinophils, basophils, C-reactive protein, NLR, or PLR between the two groups (p > 0.05). There was also no significant difference in the patency rate between the NLR < 4.13 and NLR ≥ 4.13 groups at 12 months (NLR cut-off point = 4.13, p = 0.273). There were statistically significant differences between the primary patency rates of the PLR < 187.86 and PLR ≥ 187.86 groups at 12 months (PLR cut-off point = 187.86, p = 0.023). The cut-off value for PLR for the determination of primary patency was 187.86, with a sensitivity of 57.0% and specificity of 34.4%.

CONCLUSION

An increased level of PLR may be a risk factor for the development of early AVF restenosis after successful PTA. However, more studies are needed to validate this finding.

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.

Pro-inflammatory and pro-resolving mechanisms in the immunopathology of arteriovenous fistula maturation

Introduction: With high rates of arteriovenous fistula (AVF) failure, there is a continued need to predict other factors and mechanisms associated with maturation deficits. Given the central association of inflammation with AVF failure, with neointimal hyperplasia (NIH) as one such mechanism, inflammation must be considered in two endogenous ways, either pro-inflammatory or pro-resolving, resulting in inward or outward vascular remodeling. Areas covered: This review summarizes and critically evaluates the preclinical and interventional data underlying AVF failure in attempts to elucidate the necessary balance between inflammation and its resolution. Expert opinion: Understanding the pro-inflammatory and pro-resolving mechanisms underlying inward and outward vascular remodeling and NIH prevention with AVF maturation is a necessary effort to develop key diagnostic and therapeutic interventions towards the ongoing issue of long-term AVF patency. The ability for clinical application has progressed but is limited to the identification of key targets and pathways with little understanding of how they are related synergistically or antagonistically. Likewise, the balance between acute inflammation and pro-resolution requires pertinent temporal considerations necessary for timely therapeutic application and predictive measurement.

C-reactive protein as a prognostic risk factor for loss of arteriovenous fistula patency in hemodialyzed patients

BACKGROUND

Inflammation is a cardiovascular risk factor in hemodialysis patients, but its influence on vascular access patency is still debatable. Our prospective study investigated this issue.

METHODS

A total of 258 patients receiving an arteriovenous fistula (AVF) between 2006 and 2016 at the Municipal Hospital Arad were included. Demographic, clinical, and laboratory characteristics were collected at the time of creation of the AVF. The primary study end point was AVF patency loss, defined as an event occurring at least 2 months after AVF formation and requiring surgical revision or replacement of the fistula. The patients were followed up for a median time of 26 months.

RESULTS

In our group, the mean age was 59.7 ± 13.2 years (median, 62 years), and 60.1% were male. During follow-up, 134 patients (51.9%) maintained AVF patency, whereas 124 (48.1%) lost AVF patency within a mean time of 23.3 ± 28.1 months (median, 10.5 months). We found that age (hazard ratio [HR], 1.015; P = .035) and C-reactive protein (CRP) level (HR, 1.17; P < .0001) were associated with a higher risk of loss of AVF patency. The protective factors for AVF patency were autosomal dominant polycystic kidney disease (HR, 0.336; P = .009), pre-emptive AVF (HR, 0.648; P = .031), and higher level of triglycerides (HR, 0.998; P = .035). In the multivariate adjusted Cox model, CRP level remained an independent predictor for loss of AVF patency (HR, 1.17; 95% confidence interval, 1.1-1.3; P < .0001).

CONCLUSIONS

In our study, CRP level was an independent predictor of AVF patency loss, whereas better AVF survival was independently associated with autosomal dominant polycystic kidney disease and pre-emptive AVF. As a simple noninvasive marker of chronic inflammation, CRP level may be a useful tool to predict AVF outcomes. Further research is needed to assess the protective effects of inflammation reduction on AVF survival.

The independent association of preoperative serum albumin on the functional maturation of radiocephalic arteriovenous fistulae

PURPOSE

The aim of this study is to test the null hypothesis that preoperative albumin along with other preoperative confounders have no impact on the functional maturation of radiocephalic arteriovenous fistulae (RCAVF).

METHODS

A retrospective cohort study of n = 195 individuals undergoing RCAVF formation from July 2013 to December 2015 was conducted. The null hypothesis was assessed through chi squared test. Independent association of each variable was evaluated through univariate and multivariate logistic regression model. Pearson's correlation test was also performed between scale variables to establish their causal link.

RESULTS

Preoperative hypoalbuminaemic group of individuals demonstrated significant failure of maturation (49.3% vs. 27.2%, p = 0.002). At multivariate analysis, hypoalbuminemia remained an independent marker of fistula failure (OR 0.40, 95% CI 0.21-0.76, p = 0.004) and demonstrated a weak but a positive correlation at the endpoint of maturation (R = 0.223, p = 0.002).

CONCLUSIONS

Preoperative hypoalbuminemia (<35 mg/dL) is independently associated with 40% reduction in the functional maturation of RCAVF. Stratification of this readily available biomarker prior to RCAVF formation may require consideration subjected to further research.