Hemodialysis And Peritoneal Dialysis Patients Have Severely Impaired Endothelial Post-Occlusive Forearm Vasodilatory Response Assessed With Laser Speckle Contrast Imaging

Abstract Background and Aims Endothelial dysfunction is associated with cardiovascular events and mortality in various disease states, including end-stage-renal-disease (ESRD). Novel technological approaches have emerged for real-time assessment of endothelial reactivity. This study examined forearm skin microcirculation using Laser Speckle Contrast Imaging (LSCi) before and after arterial occlusion in ESRD patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) Method 38 patients undergoing HD were matched in a 1:1 ratio with 38 PD patients (for age, sex and dialysis vintage) and 38 controls (for age and sex). Skin microvascular reactivity parameters assessed with LSCI included baseline perfusion, occlusion perfusion, and peak perfusion during post-occlusive reactive hyperemia (PORH); time to peak perfusion; proportional change from baseline to peak perfusion; baseline and peak cutaneous vascular conductance (CVC); proportional change from baseline to peak CVC; and the amplitude of the PORH response (calculated as the difference between peak and baseline CVC). Results Baseline perfusion [HD: 46.97±14.6; PD: 49.32±18.07; controls: 42.02±11.94 Laser-Specle-Perfusion-Units (LSPU), p=0.097] and peak post-occlusion perfusion (104.77±28.68 vs 109.04±40.77 vs 116.96±30.96 LSPU, p=0.238) did not differ between groups. However, the post-occlusive vascular response was completely different, since time to peak response (HD: 7.24±6.99; PD: 10.68±9.45; controls: 11.11±5.1 sec, p=0.003) and the (%) increase from baseline to peak perfusion (HD: 133%±66; PD: 149%±125; controls: 187%±61, p=0.001) was significantly lower in ESRD patients. ESRD patients had also lower levels of peak CVC, indicating the maximum capillary recruitment (HD: 1.05±0.3; PD: 1.07±0.44; controls: 1.57±0.52 LSPU/mmHg, p<0.001), lower % increase of CVC at peak (p=0.001), and lower amplitude of the PORH response (p=0.001) (a measure of the difference between baseline and maximum capillary recruitment). Conclusion Using this novel non-invasive technology endothelial post-occlusive skin vasodilatory response was found to be similar between HD and PD patients and significantly impaired compared to controls. Future studies are needed to assess the prognostic implications of this microcirculatory functional defect.