Effect of haemodialysis on acoustic shear wave propagation in the skin.

BACKGROUND: Diverse skin alterations may develop in patients under chronic haemodialysis. Among them, signs of premature photo-ageing have been described. AIM: To assess alterations in the physical properties of skin consistent with ageing effects and with cutaneous fluid exchanges during haemodialysis sessions. METHODS: In the first part of the study, 45 haemodialysed patients were compared to 45 age-, sex- and body-mass-index-matched healthy subjects. In the second part of the study, skin of 30 haemodialysed patients was assessed immediately before and after a haemodialysis session. The speed of ultrasound shear wave propagation was measured in each subject. Series of 16 multidirectional resonance running time measurements (RRTM) were performed on the forehead and/or the volar forearm. They were averaged for each subject. The corresponding intra-individual coefficients of variation were calculated as an estimate of the skin mechanical anisotropy. RESULTS: In both haemodialysed patients and their matched controls, RRTM values were significantly higher on the forearms than on the forehead. By contrast, no significant difference was found in RRTM values that could be ascribed to chronic haemodialysis. However, RRTM values were significantly increased as an immediate and probably transient effect of haemodialysis sessions. In healthy subjects, ageing was associated with increased RRTM values. CONCLUSION: Chronic haemodialysis does not appear to influence significantly the functional expression of the dermal ageing process. Subtle fluid movements occurring in the skin during haemodialysis sessions can be assessed by measuring non-invasively the speed of ultrasound shear wave propagation in the skin.