Antiphospholipid Antibodies Associated with Native Arteriovenous Fistula Complications in Hemodialysis Patients: A Comprehensive Review of the Literature

Research progress on the relationship between neutrophil extra-cellular traps and autogenous arteriovenous fistula thrombosis

Autogenous arteriovenous fistula (AVF) is the preferred vascular access for long-term hemodialysis, and thrombosis is one of the most common complications. In recent years, it has been found that neutrophil extra-cellular traps (NETs) play an important role in thrombosis. NETs are a kind of network structure with DNA as a skeleton and intercalated with a variety of granule proteins, proteolytic enzymes, antimicrobial peptides and histone proteins, which are released into the extracellular space by neutrophils after stimulation. In this paper, the NETs in the role of AVF thrombus formation and NETs in the value of prevention and cure of AVF thrombus complications were reviewed.

Assessment of Arteriovenous Fistula Maturation in Hemodialysis Patients with Persistently Positive Antiphospholipid Antibody: A Prospective Observational Cohort Study

BACKGROUND

Arteriovenous fistula (AVF) is the preferred vascular access option for hemodialysis (HD). The latter requires a remodeling process called maturation that can take up to 3 months. Maturation failure is a frequent complication associated with significant morbidity. The prevalence of antiphospholipid antibody (aPL) positivity in HD patients is high and may result in thrombosis of the vascular access. Recently, aPL persistent positivity has been associated with AVF maturation failure in a retrospective study including 116 patients.

METHODS

We are conducting an observational prospective cohort study aiming to evaluate this association. Included patients are planned for AVF creation, aged over 18 years old, and have an interpretable aPL assay confirmed at 12 weeks and without any other innate or acquired thrombophilia or inflammatory disease. Primary endpoints will be the evaluation of AVF maturation clinically and by ultrasound. Secondary endpoints will focus on clinical outcomes other than AVF maturation (i.e., primary patency, thrombosis or stenosis, bleeding and hemodialysis adequacy parameters).

CONCLUSIONS

This prospective observational cohort study aims to examine the possibly causative link between aPL persistent positivity and AVF maturation failure. This study was registered on ClinicalTrials.gov (ID number: NCT06112821).

Antiphospholipid antibodies positivity as a potential risk factor for restenosis following arteriovenous fistula stenting in hemodialysis patients: a pilot study

Background

The arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis. AVF stenosis is a common complication, often requiring balloon angioplasty. For recurrent stenosis, AVF stenting may be an option. Persistent antiphospholipid antibody (aPL) positivity is frequently observed in hemodialysis (HD) patients and is associated with AVF thrombosis and stenosis. This study aimed to evaluate AVF stent survival without stenosis in aPL-positive hemodialysis patients.

Methods

A monocentric retrospective observational study was conducted on 35 patients who underwent AVF stenting between 1st January 2014 and 31st December 2023. The patients were divided into two groups: the aPL+ group [defined by a score of 3 or more based on the laboratory criteria of the 2023 ACR/EULAR for antiphospholipid syndrome (APS)] and the control group. Intrastent restenosis was defined as a chronic change in the AVFphysical examination or blood flow, confirmed by ultrasound (US) or angiography. Kaplan-Meier survival analysis was used to estimate the probability of stent survival without restenosis.

Results

The prevalence of intrastent restenosis was significantly higher in the aPL+ group at 24 months. The Kaplan-Meier survival analysis showed a significantly lower probability of AVF stent survival without restenosis in the aPL+ group (age-adjusted Hazard Ratio, 2.13 [IC95%, 1.70-2.69]).

Conclusion

To the best of our knowledge, we describe for the first time a statistically significant association between aPL+ and AVF intrastent restenosis. Intimal hyperplasia is a non-thrombotic lesion associated with aPL+ and is linked to the mammalian target of rapamycin (mTOR) signaling pathway. We hypothesize that aPL may contribute to intrastent restenosis by inducing intimal hyperplasia. Whether this phenomenon is mTOR-mediated and whether sirolimus-eluting stents or balloons could be a better option for aPL+ patients requires further study.

Correlation between pre-operative VE-cadherin and DLL4 and the maturation after primary arteriovenous fistula in uremic patients

Aims

Uremic patients require dialysis to replace the declined kidney function, and arteriovenous fistula (AVF) is a commonly used dialysis access route. Our study aimed to explore vascular endothelial cells cadherin (VE-cadherin) and Delta-like ligand 4 (DLL4) expression in uremic patients undergoing primary AVF surgery and their correlation with AVF maturation.

Methods

We conducted a prospective study that included n = 55 voluntary uremic patients receiving their initial AVF procedure for renal replacement therapy, subjects were divided into a mature group and a failure group based on whether the AVF matured within 3 months post-operatively. We analyzed the association of VE-cadherin and DLL4 with AVF maturation by examining their expression levels in serum and the endothelium of cephalic veins.

Results

Pre-operative serum VE-cadherin, in the mature group measured 125.07 (106.77-167.65) ng/L, and DLL4 was 92.78 (83.83-106.72) pg/mL, while the failure group had VE-cadherin at 95.40 (79.03-107.16) ng/L (P = 0.001), and DLL4 at 60.42 (43.98-80.15) pg/mL with a statistical significant; (P = 0.002), binary logistic regression analysis indicated a significant association between cephalic vein diameter, VE-cadherin, DLL4 levels, and AVF immaturity (P = 0.024, P = 0.014 respectively). Immunohistochemical staining showed slightly higher VE-cadherin levels in the mature group than in the failure group (P = 0.366). DLL4 was primarily located in the cell membrane and cytoplasm, concentrated in the inner membrane, with significantly higher levels in the mature group compared to the failure group (P = 0.027).

Conclusion

The failure group exhibited lower levels of VE-cadherin and DLL4 in serum and vascular tissue, these results suggest that VE-cadherin and DLL4 might play pivotal regulatory roles in the onset and the progression of fistula immaturity, potentially serving as promising targets for future interventions.

Antiphospholipid antibody positivity is associated with maturation failure and thrombosis of native arteriovenous fistula: a retrospective study in HD patients

Background and hypothesis

The prevalence of antiphospholipid antibody (aPL) is high among hemodialysis (HD) patients compared to the general population and is inconsistently associated with arteriovenous fistula (AVF) thrombosis or stenosis. The association with maturation failure has never been investigated. This study aims to evaluate native AVF complications (thrombosis, stenosis, and maturation failure) and primary patency in aPL positive HD patients.

Methods

We retrospectively identified 116 HD patients with native AVF. We collected the aPL profiles, the clinical and biological data potentially involved in AVF maturation failure, thrombosis, and stenosis, and investigated the association of these complications and aPL positivity. Kaplan-Meier survival analysis was performed.

Results

In our cohort, the prevalence of aPL persistent positivity was 32.7% and this was strongly associated with AVF maturation failure defined by ultrasound. aPL persistent positivity was a strong predictor in multivariate analysis and this association was independent of AVF stenosis or thrombosis during maturation process. There was no association with primary and functional primary patency, and stenosis. However, aPL persistent positivity according to ACR/EULAR classification criteria was associated with thrombosis when compared to strictly negative aPL patients.

Conclusions

In our cohort, aPL persistent positivity was significantly associated with AVF maturation failure and thrombosis but not with AVF stenosis. To our knowledge, we report for the first time, a statistically significant association between aPL positivity and delay or absence of native AVF maturation.

Diagnosis and Management of Catastrophic Antiphospholipid Syndrome and the Potential Impact of the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria

Catastrophic antiphospholipid syndrome (CAPS) is a rare and life-threatening condition characterized by the persistence of antiphospholipid antibodies and occurrence of multiple vascular occlusive events. CAPS currently remains a diagnostic challenge and requires urgent treatment. The diagnosis of CAPS is made difficult by classification criteria used as diagnostic criteria in clinical practice, knowledge derived from retrospective data and case reports, confounding clinical and biological features, and its rapid onset and mortality. The absence of prospective studies of CAPS limits the strength of evidence for guideline treatment protocols. This comprehensive review summarizes the current understanding of the disease, and discusses how the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria impact the definition and therapeutic management of CAPS, which is considered the most severe form of APS. The correct integration of 2023 ACR/EULAR APS classification criteria is poised to facilitate CAPS diagnosis, particularly in critical situations, offering a promising avenue for improved outcomes.