Background/Purpose:  Vasculopathy is a prominent feature of systemic sclerosis (SSc, scleroderma) and is involved in end-stage manifestations such as pulmonary arterial hypertension (PAH), digital ulcer (DU), and scleroderma renal crisis (SRC). However, the extent to which vascular function changes in patients diagnosed with SSc is uncertain. We hypothesized that microvascular function assessed by sublingual videomicroscopy would be worse in SSc patients with end-stage manifestations compared to those patients without.

Methods:  SSc patients were recruited from the University of Utah SSc Clinic between October 2015 and April 2016 and data were obtained from 34 patients without (ES^–) and 19 patients with (ES⁺) end-stage disease (one or more of DU, PAH, SRC). Microvascular function was assessed using sublingual videomicroscopy and automated capture and analysis of vessels between 5 and 25 µm in diameter (Glycocheck). Vessels were grouped into tertiles by diameter (5-9-, 10-19-, 20-25- µm) and analysed for the density of well perfused microvessels (density), red blood cell (RBC) filling percentage, and the depth of penetration of RBCs into the vessel wall (perfused boundary region, PBR; an estimate of glycocalyx integrity). Glycocheck data were analysed using one-tailed independent samples t-test and alpha set at 0.05 (SPSS, IBM).

Results:  The mean (±SEM) age of ES^– was 55±2 (all female; 29 Caucasian, 4 Hispanic, 1 Native American) and ES⁺ was 57±3 years (3 males; 15 Caucasian, 3 Hispanic, 1 Native American). Mean duration of SSc disease and duration of Raynaud’s phenomenon was, respectively, 8±1 and 13±2 (ES^–) and 9±2 and 11±3 (ES⁺) years. There were no differences in age, height, weight, BMI, systolic or diastolic blood pressure between groups. When microvessels of all sizes were analysed, there were no differences in microvessel density, RBC% or PBR. When analysed by tertile, there were significant differences in microvessel density (ES^– vs. ES⁺: 171±17 vs. 122±15 µm/mm²) and RBC filling (ES^– vs. ES⁺: 72±1 vs. 68±3 %) in the microvessels with largest diameter (20-25- µm), but no differences in PBR. There were no differences in any microvascular measurements in the other (smaller diameter) tertiles.

Conclusion:   From this small sample, we found that some, but not all, markers of sublingual microvascular function were worse in SSc patients with end-stage manifestations of the disease compared to those without. Follow-up is needed, but this initial finding suggests that deteriorating microvascular function may be part of the natural history of SSc. These specific aspects of vascular function may be useful targets in the treatment of SSc.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/microvascular-function-in-systemic-sclerosis-patients-with-end-stage-vascular-manifestations-of-the-disease/