Chronic prothrombotic tendency in patients with granulomatosis with polyangiitis.

INTRODUCTION Patients with granulomatosis with polyangiitis (GPA) show increased tendency toward thromboembolic phenomena in exacerbation of their disease. OBJECTIVES The aim of the study was to evaluate thrombin generation potential and fibrinolytic plasma activity in patients with GPA, both in exacerbation and in remission. PATIENTS AND METHODS We included 38 patients with GPA: 18 with exacerbated GPA and 20 in remission. The control group included 39 healthy participants matched for age and sex. Plasma thrombogenic potential was assessed using calibrated automated thrombography. Plasma fibrinolytic potential was assessed using clot lysis time (CLT). We also measured levels of inflammatory markers, thrombomodulin, and fibrinolysis proteins in all participants. RESULTS In the whole group of patients with GPA, endogenous thrombin potential was higher by about 25% (P <0.001), while CLT was lower by about 20% (P = 0.02) when compared with controls. The endogenous thrombin potential was higher, the CLT lower, and the levels of thrombomodulin and inflammation markers (C‑reactive protein, fibrinogen, factor VIII) higher both in patients with exacerbation and in remission than in the control group; no such differences were noted when comparing those with exacerbation and those in remission, however. The only parameter that differentiated patients with GPA exacerbation from those in remission was the D‑dimer level (median [interquartile range], 1151 [597.2-2468.7] ng/ml vs 340.4 [255.1-500.7] ng/ml; P <0.001), a marker of lysis of intravascularly formed fibrin. CONCLUSIONS Patients with GPA show an increased prothrombotic state, regardless of the disease phase. This is probably related to ongoing low-grade inflammation and endothelial injury. Large clinical studies are required to address the need for, and appropriate type of, antithrombotic prophylaxis during the course of GPA.