Evaluation of common femoral vein thickness as a diagnostic tool for Behçet's disease in a non-endemic area.

Objectives: To evaluate common femoral vein thickness (CFVT) as a diagnostic tool in Brazilian patients with Behçet's disease (BD) and to analyse associations between increased CFVT and disease features.

Methods: A cross-sectional study was performed including 100 BD patients and 100 controls. The CFVT and the diameters of great saphenous vein (GSV), and small saphenous vein (SSV) were measured by Doppler ultrasound.

Results: BD patients had higher right CFVT [0.600mm (0.500-0.700) vs. 0.525mm (0.450-0.637); p=0.012] and left CFVT [0.550mm (0.450-0.650) vs. 0.500mm (0.450-0.550); p=0.004] compared to controls. Vascular involvement of BD and previous deep venous thrombosis were associated with increased CFVT (p<0.05). The number of vascular events correlated with right and left CFVT (Rho = 0.475 p=0.030 and Rho = 0.429 p=0.052, respectively). The 0.575mm cut-off point of right and left CFVT had area under the curve (AUC) of 0.602; 95% confidence interval (95% CI): 0.524-0.680 and AUC: 0.615; 95% CI: 0.537-0.693, respectively. The right and left CFVT had a sensitivity for BD diagnosis of 52% and 43%, and a specificity of 64% and 77%, respectively. No significant differences were found between BD patients and controls regarding the GSV and SSV diameters in both legs (p>0.05).

Conclusions: In this study, CFVT measurement was not shown to be a reliable diagnostic test for BD. CFVT was increased in BD patients presenting vascular involvement and correlated with the number of previous events.