Diffuse endothelial dysfunction is common to ANCA associated systemic vasculitis and polyarteritis nodosa.

Area of Science:

• Cardiovascular Medicine
• Rheumatology
• Vascular Biology

Background:

• Systemic rheumatic diseases are linked to increased cardiovascular mortality, potentially due to accelerated atherosclerosis.
• Endothelial cell dysfunction (ECD), marked by impaired endothelium-dependent vasodilation, is an early indicator of atherosclerosis.
• Previous studies indicated ECD in the brachial artery of patients with primary systemic necrotising vasculitis (SNV).

Purpose of the Study:

• To investigate the prevalence of ECD across a broader range of primary SNV.
• To determine if ECD is confined to major arteries or also affects microvasculature.
• To assess the influence of vasculitis subgroup, antineutrophil cytoplasmic antibody (ANCA) status, and renal involvement on endothelial function.

Main Methods:

• Fifty-four patients with various primary vasculitides and age-matched controls were recruited.
• Flow-mediated brachial artery vasodilatation was assessed using high-resolution ultrasound.
• Dermal microvascular responses were measured using laser Doppler flowmetry.

Main Results:

• ECD was observed in all studied primary SNV subgroups, including ANCA-associated vasculitis and polyarteritis nodosa, compared to controls.
• Significant endothelial impairment was found in both major arteries and dermal microvasculature.
• The extent of ECD was independent of vessel size affected by vasculitis, ANCA status, ANCA titre, or renal involvement.

Conclusions:

• Diffuse endothelial dysfunction is prevalent in primary systemic vasculitis and predicts atherosclerotic disease.
• Vascular bed involvement in ECD is not determined by the target vessel size or ANCA association.
• This systemic endothelial dysfunction appears to be a consequence of primary vasculitis, separate from local inflammatory processes.