Perfusion-induced renal hardness measured by Shore durometer: a novel, low-cost biomarker of donor kidney quality.

Quantitative assessment of donor kidney quality remains challenging in transplantation medicine. This study investigated the correlation between Shore durometer-measured renal hardness and established quality indicators (hypothermic machine perfusion [HMP] parameters and pathological scores) in deceased donor kidneys. We prospectively analyzed 58 kidneys from 29 deceased donors. Renal hardness was measured at 10 standardized locations before and after perfusion using a Shore durometer (Type OOO). HMP parameters (flow rate and resistance index [RI]) were recorded during machine perfusion, and histological assessment was performed using Remuzzi scoring. Pearson correlation analysis examined relationships between hardness parameters (pre-perfusion, post-perfusion, and perfusion-induced difference) and quality indicators. Pre-perfusion hardness correlated significantly with HMP resistance (r = 0.745, p < 0.001) and vascular damage scores (r = 0.299, p = 0.023). The perfusion-induced hardness difference showed strong negative correlations with all pathological scores (Remuzzi: r=-0.602; glomerulosclerosis: r=-0.517; interstitial fibrosis: r=-0.454; tubular atrophy: r=-0.403; vascular damage: r=-0.385; all p < 0.05). Shore durometer-measured kidney hardness significantly correlates with both HMP parameters and histological scores, with perfusion-induced hardness change emerging as a particularly promising indicator of underlying pathology. These findings support incorporating quantitative hardness assessment into donor kidney evaluation protocols.