To evaluate the prevalence of asymptomatic deep vein thrombosis (DVT) detected with duplex ultrasonography in the consecutive patients with ANCA-associated vasculitis.
Material and methods
Ninety nine consecutive patients with ANCA-associated vasculitides were screened for asymptomatic DVT by venous color duplex ultrasonography. For estimation of the risk of VTE we used the Padua Prediction Score. The control group was composed of 514 consecutive patients of comparable average age and gender and without signs and symptoms of VTE who were referred for venous duplex ultrasonography to the same laboratory.
Asymptomatic distal DVT was found in 8 of 99 patients (8.1%) with ANCA-associated vasculitis and in 2 of 514 control patients (0.4%). The age- and gender-adjusted hazard ratio for DVT in patients with ANCA-associated vasculitis was 22.5 (95% confidence interval 4.7 to 107.7) as compared with the control group. This association was similar in patients with different vasculitides and even stronger in the presence of active inflammation and within the first 6 months after diagnosis. The prevalence of classic risk factors associated with VTE (e.g. obesity, elderly age, diabetes mellitus, a history of VTE) did not differ significantly between patients with and without asymptomatic DVT. All 8 patients with DVT were at a low risk of VTE according to the Padua Prediction Score.
A high prevalence of asymptomatic DVT detected by venous ultrasonography justifies a wider screening within the first 6 months after diagnosis of ANCA-associated vasculitis, though the clinical relevance of isolated distal DVT, especially asymptomatic, is not clearly established.