Clinical associations with venous thromboembolism in anti-neutrophil cytoplasm antibody-associated vasculitides

Renal damage and old age: risk factors for thrombosis in patients with ANCA-associated vasculitis

INTRODUCTION

Thrombosis in ANCA-associated vasculitis (AAV) was prevalent and has been neglected in Chinese patients. This study tried to describe the clinical characteristics, identify the risk factors, and investigate the causal relationship between AAV and venous thromboembolism (VTE) by two-sample Mendelian randomization (MR) analysis.

METHODS

In this retrospective, observational study, we included all hospitalized AAV patients from Jan 2013 to Apr 2022 in Peking Union Medical College Hospital. We collected their clinical data for multivariate regression analysis to determine the risk factors for thrombosis. The nomogram was constructed by applying these risk factors to predict thrombosis in AAV patients. As for MR analysis, we selected single nucleotide polymorphisms (SNPs) related to AAV from published genome-wide association studies and extracted the outcome data containing deep vein thrombosis (DVT) and pulmonary embolism (PE) from the UK biobank.

RESULTS

1203 primary AAV patients were enrolled, and thrombosis occurred in 11.3%. Multivariate regression suggested that older than 65 years, EGPA, neurological involvement, lung involvement, significantly elevated serum creatinine (> 500µmol/L), and elevated D-dimer were associated with thrombosis in AAV patients. The model demonstrated satisfied discrimination with an AUC of 0.769 (95% CI, 0.726-0.812). MR analysis showed that EGPA could increase the risk of developing DVT and PE (OR = 1.0038, 95%CI = 1.0035-1.0041, P = 0.009).

CONCLUSION

Thrombosis was not rare in Chinese patients with AAV. Renal damage and old age emerged as critical risk factors for thrombosis. EGPA might have a potential causal relationship with DVT and PE.

Implication of platelets and complement C3 as link between innate immunity and tubulointerstitial injury in renal vasculitis with MPO-ANCA seropositivity

Introduction

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a potentially life-threatening systemic small-vessel vasculitis that is characterized by pauci-immune glomerulonephritis, depicting in turn a major denominator of AAV mortality. It is well established that AAV patients feature an increased risk of developing thrombotic events, and platelets are activated in AAV patients being triggered by the alternative complement pathway. Platelets guard vessels integrity and initiate thrombus formation in response to endothelial damage, further constituting a triangular interconnection with the activation of neutrophils and the complement system. We here aimed to systematically assess the relevance of platelet counts and systemic complement system activation regarding distinct histopathological lesions in ANCA-associated renal vasculitis.

Methods

A cohort of 53 biopsy-proven cases of ANCA-associated renal vasculitis were retrospectively enrolled in a single-center observational study. Univariate and multivariate regression analysis was performed to identify parameters associated with platelet counts in ANCA-associated renal vasculitis compared to disease controls. Finally, the relevance of platelets for disease course and recovery was assessed by survival analysis.

Results

Lower platelet counts correlated with markers of kidney injury including eGFR loss (p=0.0004) and lower complement C3 levels (p=0.0037). Multivariate and subgroup analysis revealed that this association was only present in the subgroup with MPO-ANCA seropositivity (eGFR loss: p=0.0009, lower C3: p=0.0032). While lower platelet counts correlated with kidney injury in the PR3-ANCA subgroup (eGFR loss: p=0.0272), we did not observe an independent association with complement C3 levels (p=0.4497). Independent of any glomerular lesion, lower platelet counts correlated with interstitial fibrosis (p=0.0313), tubular atrophy (p=0.0073), and tubulitis in areas of interstitial fibrosis and tubular atrophy (p=0.0033). Finally, we observed significant differences with increased requirement of kidney replacement therapy (KRT) or death in the subgroup below median platelet counts (HR: 4.1, 95% CI: 1.6-10, p=0.0047), associated with a lower probability of discharge and prolonged hospitalization in this subgroup (HR: 0.5, 95% CI: 0.3-0.9, p=0.0113).

Conclusion

Based on our observation that an association between platelets and complement system activation is only observed in the MPO-ANCA subgroup, this could implicate that platelets and complement C3 link innate immunity to tubulointerstitial injury in the presence of MPO-ANCA autoantibodies.

Cytomegalovirus infection is a risk factor for venous thromboembolism in ANCA-associated vasculitis

BACKGROUND

Venous thromboembolism (VTE) is a common complication in patients with anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) and confers significant morbidity and mortality. Both acute and past cytomegalovirus (CMV) infection have been identified as risk factors for VTE in immunocompetent and immunosuppressed individuals. Here, we examine whether past exposure to CMV is a risk factor for VTE amongst patients with AAV.

METHODS

We retrospectively analysed outcomes of patients with a new diagnosis of AAV from a UK cohort. All confirmed cases of VTE where CMV IgG serology was available were recorded. Retrospective collection of the same data for patients at a North American centre was used as a validation cohort.

RESULTS

VTE was common with 12% of patients from the study cohort (total 259 patients) developing an event during the median follow-up period of 8.5 years of which 60% occurred within the first 12 months following diagnosis. Sixteen percent of CMV seropositive patients developed a VTE compared with 5% of patients who were seronegative (p = 0.007) and CMV seropositivity remained an independent predictor of VTE in multivariable analysis (HR 2.96 [1.094-8.011] p = 0.033). CMV seropositivity at diagnosis was confirmed as a significant risk factor for VTE in the American validation cohort (p = 0.032).

CONCLUSIONS

VTE is common in patients with AAV, especially within the first year of diagnosis. Past infection with CMV is an independent risk factor associated with VTE in AAV.

Mechanisms of thrombosis in ANCA-associated vasculitis

Patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have a two- to threefold greater risk of developing venous as well as arterial thrombotic events. Although such thrombotic events are more commonly seen during phases of active AAV, they are also recognized to occur during AAV in remission. Endothelial injury is a key pathogenic event in AAV. Endothelial injury can be caused by neutrophil activation and release of thrombogenic tissue factor into the circulation. Neutrophil activation further results in the formation of neutrophil extracellular traps (NETs). NETs contribute to thrombosis by expressing tissue factor. NETs have also been detected in cutaneous thrombi from patients with AAV induced by hydralazine. Activated neutrophils in AAV patients release thrombogenic microparticles loaded with tissue factor which further enhances clotting of blood. Antiphospholipid antibodies (APLs) have been detected in up to a third of AAV and might also be induced by drugs such as cocaine adulterated with levamisole and propylthiouracil, which are known to trigger AAV. Such APLs further drive the thrombosis in AAV. Once thrombogenesis occurs, the homeostatic mechanisms resulting in clot dissolution are further impaired in AAV due to anti-plasminogen antibodies. The ongoing pandemic of coronavirus disease 2019 (COVID-19) is associated with endothelial injury and NETosis, mechanisms which are in common with AAV. Reports of new-onset AAV following COVID-19 have been described in the literature, and there could be shared mechanisms driving these processes that require further evaluation.

ANCA Status or Clinical Phenotype - What Counts More?

PURPOSE OF REVIEW

There is ongoing debate concerning the classification of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. That is, whether classification should be based on the serotype (proteinase 3 (PR3)- or myeloperoxidase (MPO)-ANCA) or on the clinical phenotype (granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA)). To add clarity, this review focused on integration of the most recent literature.

RECENT FINDINGS

Large clinical trials have provided evidence that a serology-based risk assessment for relapses is more predictive than distinction based on the phenotype. Research conducted in the past decade indicated that a serology-based approach more closely resembles the genetic associations, the clinical presentation (i.e., lung involvement), biomarker biology, treatment response, and is also predicting comorbidities (such as cardiovascular death). Our review highlights that a serology-based approach could replace a phenotype-based approach to classify ANCA-associated vasculitides. In future, clinical trials and observational studies will presumably focus on this distinction and, as such, translate into a "personalized medicine."

Comorbidities in ANCA-associated vasculitis

The prognosis of patients with ANCA-associated vasculitis has improved over the past decades, but overall survival rates are still unsatisfactory. Recent research has focused on complications of immunosuppressive measures and comorbidities of ANCA-associated vasculitis. This review focuses on thromboembolic and cardiovascular events. A considerably increased risk of thromboembolic events has been reported, which is associated with active disease and impaired coagulation factors. There is mounting evidence that a hypercoagulable state is present even in patients in remission, and studies investigating the impact of tailored anticoagulation are needed to reduce the burden of thromboembolism. Cardiovascular mortality is one of the leading causes of death and accelerated atherosclerosis is frequently observed in patients with ANCA-associated vasculitis. A high frequency of patients develops hypertension, diabetes mellitus and hypercholesterolaemia, either as a consequence of immunosuppression or associated with the underlying disease. The current control of modifiable cardiovascular risk factors is insufficient and thorough reviews should be performed periodically. Treatment of these risk factors should be adopted according to current recommendations related to individual cardiovascular risk prediction.

Venous thromboembolism in anti-neutrophil cytoplasmic antibody-associated vasculitis: an underlying prothrombotic condition?

Objectives

We investigated the incidence and potential underlying risk factors of venous thromboembolism (VTE) in patients with AAV. We assessed haemostatic disturbances and factors that might contribute to the risk of development of VTE.

Methods

ANCA-positive AAV patients (n = 187) were included. Previously identified risk factors for VTE and current medication were retrieved from the medical records. We assessed haemostasis using different methods [endogenous thrombin potential (ETP), overall haemostatic potential (OHP), overall coagulation potential (OCP) and overall fibrinolysis potential (OFP)] in patients with active AAV (n = 19), inactive AAV (n = 15) and healthy controls (n = 15).

Results

Twenty-eight VTEs occurred in 24 patients over a total follow-up time of 1020 person-years. A majority of VTEs occurred within the first year after diagnosis. Old age (P < 0.01), ongoing prednisolone treatment and recent rituximab administration were more common in the VTE group (P < 0.05 for all). ETP and OHP were significantly increased and OFP significantly decreased in plasma from active compared with inactive AAV patients (P < 0.05, P < 0.01 and P < 0.05, respectively) and healthy controls (P < 0.001). We could not confirm previously reported risk factors for VTE development.

Conclusion

A high prevalence of VTE in AAV patients was seen within the first year after diagnosis, suggesting that disease activity contributes to development of VTE. Old age and concurrent treatment should also be taken into account when estimating VTE risk. The results also indicate disturbances in the haemostatic balance towards pro-thrombotic conditions in AAV patients, where ETP and OHP might be useful markers for identifying patients at high risk.

Immunopathogenesis of ANCA-Associated Vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune disorder which affects small- and, to a lesser degree, medium-sized vessels. ANCA-associated vasculitis encompasses three disease phenotypes: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). This classification is largely based on clinical presentations and has several limitations. Recent research provided evidence that genetic background, risk of relapse, prognosis, and co-morbidities are more closely related to the ANCA serotype, proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, compared to the disease phenotypes GPA or MPA. This finding has been extended to the investigation of biomarkers predicting disease activity, which again more closely relate to the ANCA serotype. Discoveries related to the immunopathogenesis translated into clinical practice as targeted therapies are on the rise. This review will summarize the current understanding of the immunopathogenesis of ANCA-associated vasculitis and the interplay between ANCA serotype and proposed disease biomarkers and illustrate how the extending knowledge of the immunopathogenesis will likely translate into development of a personalized medicine approach in the management of ANCA-associated vasculitis.

Incidence and Risk Factors of Venous Thromboembolic Events in Patients with ANCA-Glomerulonephritis: A Cohort Study from the Maine-Anjou Registry

(1) Introduction: The incidence of venous thromboembolisms (VTE) has not been extensively analyzed in patients with antineutrophil cytoplasmic antibody (ANCA)-glomerulonephritis (ANCA-GN). Thus, the aim of the present study was to assess the frequency and the risk factors of VTE in patients with ANCA-GN. (2) Methods: Patients from the Maine-Anjou ANCA-associated vasculitis (AAV) registry with a biopsy showing pauci-immune glomerulonephritis were included. VTE events, site, and interval from AAV diagnosis were analyzed. (3) Results: 133 patients fulfilled the inclusion criteria of the study and were analyzed. VTE episodes were diagnosed in 23/133 (17.3%) patients at a median delay of 3 months from ANCA-GN diagnosis. Patients with VTE had lower serum albumin (p = 0.040), were less frequently on statin therapy (p = 0.009) and had less frequently proteinase-3 (PR3)-ANCAs (p = 0.078). Univariate analysis identified higher age (p = 0.022), lower serum albumin (p = 0.030), lack of statin therapy (p = 0.009), and rituximab treatment (p = 0.018) as significant risk factors of VTE. In multivariate analysis, only lack of statin therapy (HR 4.873; p = 0.042) was significantly associated with VTE. (4) Conclusion: Patients with ANCA-GN are at high risk of VTE, especially within the first months following AAV diagnosis. Our results suggest that statin therapy is associated with a lower risk of VTE in ANCA-GN patients.

Role of direct oral anticoagulants in patients with kidney disease

The anticoagulation field is experiencing a renaissance that began with regulatory approval of the direct thrombin inhibitor dabigatran, a direct oral anticoagulant (DOAC), in 2010. The DOAC medication class has rapidly evolved to include the additional approval of 4 direct factor Xa inhibitors. Commensurately, DOAC use has increased and collectively account for the majority of new anticoagulant prescriptions. Despite exclusion of patients with moderate-to-severe kidney disease from most pivotal DOAC trials, DOACs are increasingly used in this setting. An advantage of DOACs is similar or improved antithrombotic efficacy with less bleeding risk when compared with traditional agents. Several post hoc analyses, retrospective studies, claims data studies, and meta-analyses suggest that these benefits extend to patients with kidney disease. However, the lack of randomized controlled trial data in specific kidney disease settings, with their unique pathophysiology, should be a call to action for the kidney community to systematically study these agents, especially because early data suggest that DOACs may pose less risk of anticoagulant-related nephropathy than do vitamin K antagonists. Most DOACs are renally cleared and are significantly protein bound in circulation; thus, the pharmacokinetics of these drugs are influenced by reduced renal function and proteinuria. DOACs are susceptible to altered metabolism by P-glycoprotein inhibitors and inducers, including drugs commonly used for the management of kidney disease comorbidities. We summarize the currently available literature on DOAC use in kidney disease and illustrate knowledge gaps that represent important opportunities for prospective investigation.

Association of Pulmonary Hemorrhage, Positive Proteinase 3, and Urinary Red Blood Cell Casts With Venous Thromboembolism in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

OBJECTIVE

To assess the frequency of venous thromboembolism (VTE) events in the Rituximab in Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis (RAVE) trial and identify novel potential risk factors.

METHODS

VTE events in 197 patients enrolled in the RAVE trial were analyzed. Baseline demographic and clinical characteristics were recorded, and univariate and multivariate analyses were performed to identify factors associated with VTE in ANCA-associated vasculitis (AAV).

RESULTS

VTE occurred in 16 patients (8.1%) with an overall average time to event of 1.5 months (range 1.0-2.75). In univariate analyses with calculation of hazard ratios (HRs) and 95% confidence intervals (95% CIs), heart involvement (HR 17.408 [95% CI 2.247-134.842]; P = 0.006), positive proteinase 3 (PR3)-ANCA (HR 7.731 [95% CI 1.021-58.545]; P = 0.048), pulmonary hemorrhage (HR 3.889 [95% CI 1.448-10.448]; P = 0.008), and the presence of red blood cell casts (HR 15.617 [95% CI 3.491-69.854]; P < 0.001) were associated with the onset of VTE. In multivariate models adjusted for age and sex, the significant associations between VTE events and heart involvement (HR 21.836 [95% CI 2.566-185.805]; P = 0.005), PR3-ANCA (HR 9.12 [95% CI 1.158-71.839]; P = 0.036), pulmonary hemorrhage (HR 3.91 [95% CI 1.453-10.522]; P = 0.007), and urinary red blood cell casts (HR 16.455 [95% CI 3.607-75.075]; P < 0.001) remained.

CONCLUSION

Patients diagnosed as having AAV with pulmonary hemorrhage, positive PR3-ANCA, heart involvement, and the presence of red blood cell casts are at an increased risk to develop VTE. Further studies are needed to confirm and expand these findings and to explore the mechanisms of hypercoagulability in these patients with the aim of informing potential targets for therapeutic intervention.

Elevated Microparticle Tissue Factor Activity Differentiates Patients With Venous Thromboembolism in Anti-neutrophil Cytoplasmic Autoantibody Vasculitis

Introduction

Venous thromboembolism (VTE) is a life-threatening complication of anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis whose mechanism remains incompletely elucidated. We tested the hypothesis that elevated microparticle tissue factor activity (MPTFa) or anti-plasminogen antibodies (anti-Plg) may identify patients at risk for VTE.

Methods

In this prospective study, patients were enrolled during active disease and followed longitudinally. Twelve patients who experienced a VTE (VTE^pos) were compared with patients without VTE (VTE^neg, n = 29) and healthy controls (HC, n = 70). MPTFa, anti-Plg, interleukin-6, high-sensitivity C-reactive protein (hs-CRP), D-dimer, serum creatinine, and serum albumin were assessed. Fisher’s exact tests and Wilcoxon tests compared categorical and continuous variables, respectively. Cox regression for time to VTE or last follow-up was performed.

Results

VTE^pos patients had higher MPTFa (peak median = 14.0, interquartile range = 4.3–36.6) than HC (0, 0–3.5) and VTE^neg patients (0, 0–1.4). In time-to-event analysis, MPTFa was associated with VTE when measured during both active disease (hazard ratio [HR]; 95% confidence interval [CI]: 1.04; 1.01–1.08) and remission (1.4; 1.11–1.77). Anti-Plg during remission was also associated with VTE (1.17; 1.03–1.33). Each g/dl decrease of serum albumin was associated with a 4-fold increase in VTE risk (4.4; 1.5–12.9). Adjusting for estimated glomerular filtration rate (eGFR), anti-Plg during remission remained significantly associated with VTE.

Conclusion

Elevated MPTFa and increased anti-Plg in remission are strong indicators of VTE independent of renal function. Association of anti-Plg during remission with VTE implies hypercoagulability even during disease quiescence. Hypoalbuminemia strongly portends VTE risk, which is a novel finding in ANCA vasculitis. A thrombotic signature would allow improved management of patients to minimize VTE risk and complications of anticoagulation.

Analysis of Antineutrophil Cytoplasm Antibody from 118 730 Patients in Tertiary Hospitals in Jiangxi Province, China

BACKGROUND The discovery of antineutrophil cytoplasm antibody (ANCA) makes the early diagnosis of primary vasculitis possible, and also has important guiding significance for the diagnosis and treatment of secondary vasculitis. This study aimed to investigate the clinical significance of ANCA. MATERIAL AND METHODS ANCA was detected by indirect immunofluorescence assay (IIF), and anti-myeloperoxidase (MPO) antibody, and anti-proteinase 3 (PR3) antibody were detected by ELISA. The results were analyzed retrospectively. RESULTS Among 118 730 patients, a total of 5853 (4.93%) were positive for ANCA. In the positive cases, 3.98% were male and 6.33% were female, with significant differences (χ²=123.38, P<0.01). For ANCA, the department with the highest positive rate (15.06%) was the Department of Rheumatology, followed by 7.78% in the Department of Dermatology, 6.79% in the Department of Nephrology, and 5.72% in the Department of Traditional Chinese Medicine (TCM). Anti-PR3 and cANCA were highly specific in primary vasculitis (P<0.01). Anti-MPO and pANCA had high specificity for other autoimmune diseases (P<0.01). CONCLUSIONS ANCA has important guiding significance for vasculitis-related diseases. Therefore, it is important in the diagnosis and treatment of this disease and has value in clinical practice.