INCREASED CAPILLARY-PERMEABILITY IN SYSTEMIC RHEUMATOID VASCULITIS - DETECTION BY DYNAMIC FLUORESCENCE NAILFOLD VIDEOMICROSCOPY

Objective. Several histological studies suggest a vascular involvement in rheumatoid arthritis (RA). We evaluated morphological and function al changes of skin capillaries in patients with RA. Methods. We studie d capillary permeability by nailfold fluorescence videomicroscopy in p atients with RA with and without systemic vasculitis to establish the sensitivity, specificity, and the prognostic value of the technique fo r the diagnosis of systemic rheumatoid vasculitis (SRV). Nine patients with SRV, 22 patients with active RA without signs of vasculitis, and 16 controls were evaluated. Results. No difference in conventional ca pillaroscopy was observed when we compared patients with SRV and RA. U sing fluorescence videomicroscopy after intravenous injection of fluor escein sodium, we observed an increase of transcapillary dye diffusion in 9/9 patients with SRV, in 13/22 patients with RA without vasculiti s and in 4/16 control patients. Our results give a sensitivity of 100% in SRV, a specificity of 44%, a positive predictive value of 34% and a negative predictive value of 100%. Conclusion. Our present study poi nts out the functional alteration of the capillary wall in patients wi th RA with or without vasculitis and suggests the usefulness of dynami c fluorescence nailfold capillaroscopy in patients with RA when system ic vasculitis is suspected, not as a diagnostic tool, but because of t he high negative predictive value of the technique.