Activation of endothelium, coagulation and fibrinolysis is enhanced and associates with renal anti-neutrophil cytoplasmic antibody-associated vasculitis

While the incidence of thromboembolism in anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV) is high, the coagulation and fibrinolysis profile in AAV patients remains poorly characterized. We aimed at studying this profile in association with vasculitis activity and renal function. This prospective study included 21 AAV patients with renal disease and 40 controls with other chronic kidney disease. Platelet count, antithrombin, FVIII:C, von Willebrand factor (VWF) activities (VWF:RCo) and antigen (VWF:Ag), fibrinogen, prothrombin fragments (F1 + 2), fibrin degradation product d-dimer and the presence of antiphospholipid antibodies were measured during the active and remission states of the AAV and at the baseline in controls. Occurrence of thromboembolic events was recorded. F1 + 2 was 2.6-fold and d-dimer was 5-fold higher during the active AAV than its remission (median 563 versus 212 pM and 3.0 versus 0.6 mg/L, P = 0.001 for both). FVIII:C (median 228%), VWF:RCo (198%) and VWF:Ag (222%) were the highest among the patients with active AAV and remained elevated also under remission. In active AAV, both F1 + 2 and d-dimer clearly associated with impaired renal function (r = -0.67, P = 0.001 and r = -0.66, P = 0.001). In AAV patients, two thromboembolic events occurred during the follow-up. In active renal AAV, thrombin formation and especially fibrin turnover prevail compared both with remission and other kidney diseases. Overall, AAV is characterized by an enhanced coagulation, especially FVIII activity, which continues partly in remission.