A Modified Kidney Perfusion System for Improved Data Acquisition and Assessment of Renal Function and Metabolism

PURPOSE

In the United States, there are over 88,000 candidates on the waitlist for kidney donation as of December 2022 with less than 42,0000 transplant procedures being recorded in the same year. Coinciding with this continued disparity has been a growing interest in the technology to preserve and improve the function of kidneys for transplantation, most notably machine perfusion (MP). Studies have shown that MP is superior to static cold storage, the most common method of kidney preservation used globally, which has allowed transplant programs to expand the current donor pool by use of marginal donor kidneys. Despite these advancements, machine perfusion technology used clinically is limited in its use for obtaining critical information regarding the real-time assessment of renal function, fluid dynamics, and metabolism. Here we discuss the development of a modified kidney perfusion system that allows for enhanced data acquisition of perfusion parameters, renal arterial and venous sampling, and organ monitoring within a controlled environment.

METHODS

The modified kidney perfusion system was assembled to house and monitor a singular organ. The organ is placed in a chamber that allows for maximal cooling to 2˚C - 6˚C or temperature regulation up to room temperature. Renal artery and vein cannulation allow for accurate perfusate sampling in different parts of the system without disruption of organ perfusion. Continuous monitoring of pressure, flow, and resistance is performed using pressure and flow transducers in line with the polyethylene tubing. In line with the system includes an air trap to prevent gas emboli, modifiable filter, and screen for large particulate matter. A specialized rotor allows for pulsatile perfusion into the kidney while a servomotor is used to set a desired pressure or flow into the system. Values for flow, pressure, resistance are recorded in real time using Spike2 software and the corresponding waveforms displayed in the program.

RESULTS & CONCLUSION

The limitations of machine perfusion technology currently used clinically hinder the ability to obtain data for interpretation of pre-transplant renal function. This modified kidney perfusion system improves upon many of these limitations and provides entirely new methods to gain insight on kidney function. Assessment of renal metabolite production and injury markers can be obtained from multiple sites throughout the perfusion circuit and instantaneous recording of both pressure and flow waveforms throughout the duration of machine perfusion.