Systemic sclerosis induces pronounced peripheral vascular dysfunction characterized by blunted peripheral vasoreactivity and endothelial dysfunction.

Abstract

Systemic sclerosis (SSc) vasculopathy can result in a digital ulcer (DU) and/or pulmonary arterial hypertension (PAH). We hypothesized that bedside brachial artery flow-mediated dilation (FMD) testing with duplex ultrasound could be used in SSc patients to identify features of patients at risk for DU or PAH. Thirty-eight SSc patients were compared to 52 age-matched healthy controls from the VAMC Utah Vascular Research Laboratory. Peripheral hemodynamics, arterial structure, and endothelial function were assessed by duplex ultrasound. A blood pressure cuff was applied to the forearm and 5-min ischemia was induced. Post-occlusion, brachial artery vascular reactivity (peak hyperemia/area under the curve [AUC]), shear rate, and endothelial function (FMD) were measured. SSc patients had smaller brachial artery diameters (p < 0.001) and less reactive hyperemia (p < 0.001), peak shear rate (p = 0.03), and brachial artery FMD (p < 0.001) compared with healthy controls. Brachial artery FMD was lower (p < 0.05) in SSc patients with DU. Tertile analysis suggested the 2 lower FMD tertiles (<5.40 %) had a 40-50 % chance of presenting with DU while the SSc patients with highest FMD tertile (>5.40 %) had less than 15 % chance of DU. All brachial artery FMD measurements were similar between SSc patients with and without PAH (all p > 0.05). Compared to healthy controls, SSc patients had significantly smaller brachial artery diameter and blunted peripheral vascular reactivity and endothelial function. SSc patients with DU have even greater impairments in endothelial function compared to those without DU. FMD testing has clinical utility to identify SSc patients at risk for DU.