Thermal-structure coupling simulation during ex-vivo hypothermic perfusion of kidney

• The anatomical CAD model of vessels was developed according to the vascular cast.
• The continuous flow was formed by treating capillaries and tissue as porous media.
• Thermal-structure simulation helps clinicians to better predict flushing process.
• Larger perfusion rates could cause kidney injury due to large distortion.
• The perfusion rates should be strictly set to achieve the optimal preservation effect.

In this paper, the temperature variation and consequent thermal stress and deformation during hypothermic perfusion are numerically investigated. Hypothermic perfusion is the first step of preservation techniques that washes out of the vascular system and provides the supply of substrates and cools the kidney to the preservation temperature. A three-dimensional (3D) finite element analysis using the anatomical CAD model of kidney is developed to accurately simulate the hypothermic perfusion process. Based on the temperature field, the time evolution of thermal stress and deformation distribution are obtained. In addition, we analyze the effect on the thermal stress and deformation which cannot be easily acquired through clinical experiments. The results indicate that the thermal effects of large blood vessels could remarkably affect the temperature, thermal stress and deformation distributions. Increasing the perfusion rate could enlarge the thermal deformation, which causes the injury to the kidney. These results provide a guideline to the basic and applied research for the thermal effect on the hypothermic perfusion of kidney.