Work

54 Contrast-enhanced ultrasound to assess kidney quality during ex situ normothermic machine perfusion

Year: 2025

Type: article

Abstract: Background Normothermic machine perfusion (NMP) provides opportunity for viability assessment of donated kidneys. Diminished microvascular perfusion, despite adequate total blood flow, is a key pathophysiology in ischaemia reperfusion injury mediated acute kidney injury. Contrast-enhanced ultrasound (CEUS) could allow assessment of microvascular perfusion during renal NMP. Methods Blood-based NMP was performed on porcine kidneys, and human kidneys declined for transplant (REC15/SC/0161). Porcine kidneys were retrieved with a circulatory death model. CEUS was performed with Philips EPIQ7 Ultrasound machine and sulphur hexafluoride contrast agent, delivered as a bolus into the NMP circuit arterial limb. Microvascular perfusion quality was quantified with peak and time-to-peak values. Z-score normalisation allowed combination of cortex/medulla scores into an overall “CEUS-score”. Results In porcine kidneys (n=8), decreased quality of perfusion in renal cortex and medulla was correlated with urinary NGAL (Pearson r=0.900; P=0.002 and r=0.745; P=0.034, respectively) and tissue apoptosis (r=0.647; P=0.083 and r=0.805; P=0.016). These findings were confirmed in human kidneys (n=5). In human kidneys, “CEUS-score” at 2 hours was correlated with tissue apoptosis (r=-0.937; P=0.019) and predicted urinary NGAL at 24 hours of NMP (r=-0.925; P=0.024). Total renal flow was not correlated with these outcomes. A web app (stingle.shinyapps.io/Time_intensity_analysis) and R package (“tican”) were developed for quantitative CEUS analysis. Conclusion CEUS allows point-of-care assessment of microvascular perfusion during renal NMP, which correlates with tissue apoptosis on histology. 2-hour CEUS-score predicts the key biomarker urinary NGAL at 24 hours of NMP in human kidneys. Techniques for CEUS-quantification were developed and disseminated via open-source software.

Source: British journal of surgery

DOI: 10.1093/bjs/znaf042.068