SKIN MICROVASCULAR DYSFUNCTION IS IMPAIRED IN PATIENTS WITH SYSTEMIC VASCULITIS AND CORRELATE WITH THE DURATION OF THE DISEASE

Abstract

Objective: Systemic Vasculitides (SVs) are a highly inflammatory group of diseases characterized by significant cardiovascular mortality. Microvascular damage closely linked with accelerated atherosclerosis and thrombosis represent core pathophysiologic mechanisms contributing to the excess CV risk of patients with SVs. Skin represents a very easy accessible tissue, facilitating mechanistic non-invasive microvascular studies. In this study we aimed to assess skin microvascular function (SMF) using Laser Speckle Contrast Imaging (LSCI) technique coupled with Post-Occlusive Reactive Hyperemia (PORH) in patients with SVs and investigate correlations with inflammatory status and disease characteristics. Design and method: We consecutively recruited 60 individuals including 15 with ANCA-Associated Vasculitis, 15 with Bechet disease and 30 healthy controls matched for age, sex and cardiovascular risk factors. SMF was assessed with LSCI coupled with PORH following a standardized protocol. Results are expressed as percentage increase of flux from baseline to the peak post-occlusive response, as cutaneous vascular conductance (CVC) during baseline (baseline CVC), peak CVC and as the percentage increase (CVC increase). CVC was calculated as the ratio of mean flux in each respective period divided by mean blood pressure (BP). Moreover, we investigated the correlation between SMF and disease duration as well as disease activity, as evaluated by the Birmingham Vasculitis Activity Score (BVAS) and biomarkers of acute inflammation(C-reactive protein and erythrocyte sedimentation rate). Results: No differences were found in office BP, and basic demographic parameters between groups. Patients with SVs presented a lower base to peak flux [207 (60.1) vs 143.7 (41.0) LSPUs, p < 0.001] and CVC increase (190.0 ± 49.6 vs 149.6 ± 48.9 %, p = 0.002) compared to controls. Importantly, base to peak flux and CVC increase were significantly correlated with disease duration (p < 0.001, r = -0.563 and p < 0.001, r = 0.442 respectively). However, no significant correlation was found with disease activity markers and inflammatory status Conclusions: Patients with SVs exhibit impaired SMF as shown by a dynamic and reproducible method, namely LSCI combined with PORH. Moreover, skin microvascular impairment correlates with disease duration but not with disease activity, suggesting that a chronic, low-grade inflammatory background instead of acute inflammation may be responsible for cutaneous damage.