The Relationship Between Sublingual Microcirculatory Structure and Frailty in Renal Transplant Candidates: Exploring...

This study investigated the relationship between sublingual microcirculatory tortuosity, frailty index scores, and endothelial glycocalyx blood biomarkers in individuals with chronic kidney disease (CKD).

Sublingual microcirculatory videos were analyzed using a 0-4 tortuosity scoring scale. Plasma concentrations of syndecan-1 and soluble thrombomodulin were quantified using enzyme-linked immunosorbent assay (ELISA). Frailty status was assessed using a short-form frailty index questionnaire.

The study included 44 patients (median age 53 years, IQR 45-64) attending a kidney transplant assessment clinic, with equal representation of males and females. The median frailty index was 0.19 (IQR: 0.15-0.30), with 63.5% of participants having an FI score < 0.25. Intraclass correlation coefficient (ICC) analysis demonstrated excellent inter-observer reliability for tortuosity scoring. Frailty index scores were significantly higher in participants with tortuosity scores of 3/4 compared to those with a score of 0. No significant differences were observed in syndecan-1 or soluble thrombomodulin levels across tortuosity scores. Ordinal logistic regression identified frailty index score as the only significant predictor of tortuosity, independent of age, dialysis type, or sex.

Higher frailty index scores were associated with increased sublingual microcirculatory capillary tortuosity, though this relationship did not extend to endothelial glycocalyx biomarkers. These findings highlight the potential value of incorporating tortuosity assessment alongside density and perfusion measures in microcirculatory evaluation.