ANCA-Associated Vasculitis (AAV)


Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a term that describes a group of rare, hematologic, autoimmune conditions consisting primarily of 3 diseases: granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). These disorders are characterized by the autoimmune destruction of blood vessels, which can lead to multisystemic involvement.1

The autoimmune destruction of small blood vessels may cause disease-related complications: specifically, damage to the lungs, kidneys, and peripheral nerves.2

Pulmonary Complications of ANCA-Associated Vasculitis

Lung involvement, particularly in patients with MPA and GPA, is correlated with increased risks of morbidity and mortality. An association between interstitial lung disease (ILD) and ANCA-associated vasculitis has been reported, especially in patients with autoantibodies against myeloperoxidase.3 

Signs of pulmonary fibrosis often appear on chest radiographs4 or computed tomography scans prior to diagnosis of ANCA-associated vasculitis. Pulmonary function tests may also decline as ILD progresses. ILD adversely impacts the long-term prognosis of patients with ANCA-associated vasculitis.3

Mortality in the intensive care unit (ICU) correlated with the need for and duration of respiratory assistance, including invasive and noninvasive mechanical ventilation. In one study where researchers analyzed the reasons for ICU admission among patients with ANCA-associated vasculitis, nearly half (45.4%) of the cohort was admitted for respiratory failure. Around half of these patients presenting with respiratory failure also presented with concurrent renal failure.5

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Renal complications of ANCA-Associated Vasculitis

Another common disease-related complication of ANCA-associated vasculitis is acute or end-stage renal failure.5,6 Significant renal involvement is most common in patients with MPA followed by those with GPA, while it is a rare occurrence in patients with EGPA.6 

Despite treatment advancements, a significant proportion of patients with ANCA-associated vasculitis develop end-stage renal disease. Renal replacement therapy may decrease the likelihood of relapsing vasculitis due to antirejection treatment following kidney transplantation. Hemodialysis may also be required.6

Investigating end-organ renal involvement predominantly requires urinalysis, including active urinary sediment testing for red blood cells and casts and tests for proteinuria. Renal biopsy confirms the diagnosis and the degree of renal inflammation and fibrosis due to ANCA-associated vasculitis.7

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Neurological Complications of ANCA-Associated Vasculitis

Neurological complications occur in approximately one-third of patients with ANCA-associated vasculitis. These include muscle weakness and paresthesias consistent with a diagnosis of mononeuritis multiplex or other peripheral neuropathies, often evidenced by foot drop or wrist drop.8 Comprehensive nerve conduction studies are required to diagnose mononeuritis multiplex.7 Peripheral neuropathies and numbness lead to difficulties with walking and fine motor control requiring hand coordination.8

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Cardiovascular Complications of ANCA-Associated Vasculitis

Patients with ANCA-associated vasculitis are prone to developing cardiovascular disease. The mechanism for this predisposition is related to increased inflammation that promotes endothelial injury, blood vessel occlusion, ischemia, and platelet activation, which in turn accelerates atherosclerosis. Endothelial cell necrosis may also produce microparticles associated with unstable plaque formation, leading to adverse cardiovascular events.9 

Cardiovascular risk is highest within the first year of ANCA-associated vasculitis diagnosis and is especially high within the first 3 months. Overall, patients with ANCA-associated vasculitis demonstrate an approximately 65% higher risk of cardiovascular events compared to the general population.9 

In addition to the diagnosis of ANCA-associated vasculitis, family history, advancing age, and a medical history of dyslipidemia and hypertension all increase the risk of developing myocardial fibrosis, arrhythmias, atherosclerosis, heart failure, and myocardial infarction.9

Patients with ANCA-associated vasculitis also demonstrate an increased risk of hemorrhage, which can lead to hemorrhagic shock and death. In ANCA-associated vasculitis, hemorrhage most commonly occurs in the alveoli of the lungs; however, potentially fatal hemorrhaging can occur in the gastrointestinal tract or the brain. Cerebral hemorrhage has a persistently high mortality rate, while gastrointestinal hemorrhage can be remediated with surgical intervention.10 

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Potential complications caused by ANCA-associated vasculitis treatment include malignancy, chemical cystitis, bone marrow failure, diabetes, osteoporosis, and gonadal failure causing infertility.2,11,12 

Central neurological injuries were found to occur more frequently in patients with ANCA-associated vasculitis who were admitted to the ICU. The risk of mortality due to cerebral hemorrhaging increased among patients receiving anticoagulation treatment while on extracorporeal membrane oxygenation (ECMO).5

Rituxan® (rituximab) may further promote the development of cardiovascular disease and events due to treatment-related increases in cholesterol, triglyceride, and lipid levels; however, it simultaneously decreases cardiovascular risk by decreasing endothelial dysfunction and disease activity caused by ANCA-associated vasculitis.9

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References

  1. Yates M, Watts R. ANCA-associated vasculitis. Clin Med (Lond). 2017;17(1):60-64. doi:10.7861/clinmedicine.17-1-60
  2. Qasim A, Patel JB. ANCA positive vasculitis. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2022. Updated May 29, 2022. Accessed February 23, 2023.
  3. Alba MA, Flores-Suárez LF, Henderson AG, et al. Interstitial lung disease in ANCA vasculitis. Autoimmun Rev. 2017;16(7):722-729. doi:10.1016/j.autrev.2017.05.008
  4. Pulmonary fibrosis. Mayo Clinic. March 6, 2018. Accessed February 23, 2023.
  5. Demiselle J, Auchabie J, Beloncle F, et al. Patients with ANCA-associated vasculitis admitted to the intensive care unit with acute vasculitis manifestations: a retrospective and comparative multicentric study. Ann Intensive Care. 2017;7:39. doi:10.1186/s13613-017-0262-9
  6. Moiseev S, Novikov P, Jayne D, Mukhin N. End-stage renal disease in ANCA-associated vasculitis. Nephrol Dial Transplant. 2017;32(2):248-253. doi:10.1093/ndt/gfw046
  7. Assessment of end organ damage in ANCA associated vasculitis. GP Notebook. Accessed February 23, 2023.
  8. Hunter RW, Welsh N, Farrah TE, Gallacher PJ, Dhaun N. ANCA associated vasculitis. BMJ. 2020;369:m1070. doi:10.1136/bmj.m1070
  9. Floyd L, Morris AD, Woywodt A, Dhaygude A. Cardiovascular disease and ANCA-associated vasculitis: are we missing a beat? Clin Kidney J. 2022;15(4):618-623. doi:10.1093/ckj/sfac009
  10. Cao Y, Tian Z, Li W, Yang Y, Wang G. Hemorrhagic complications associated with PR3-ANCA crescentic glomerulonephritis. Ren Fail. 2015;37(5):745-750. doi:10.3109/0886022X.2015.1014756
  11. Robson J, Doll H, Suppiah R, et al. Damage in the anca-associated vasculitides: long-term data from the European Vasculitis Study group (EUVAS) therapeutic trials. Ann Rheum Dis. 2015;74(1):177-184. doi:10.1136/annrheumdis-2013-203927
  12. Koldingsnes W, Nossent H. Predictors of survival and organ damage in Wegener’s granulomatosis. Rheumatology (Oxford). 2002;41(5):572-581. doi:10.1093/rheumatology/41.5.572

Reviewed by Hasan Avcu, MD, on 2/24/2023.