From the Guidelines
Normothermic pulsatile perfusion is the recommended preservation technique for donor kidneys prior to transplantation, as it maintains the organ at body temperature with oxygenated blood or a blood-based solution, reducing ischemic injury and enabling organ assessment before transplantation. This method offers significant advantages over traditional static cold storage by allowing metabolic activity to continue, reducing ischemic injury, and enabling organ assessment before transplantation. The typical protocol involves connecting the kidney to a perfusion machine that circulates warm (35-37°C) oxygenated solution at physiological pressure (systolic 100-120 mmHg, diastolic 60-80 mmHg) in a pulsatile pattern mimicking normal circulation.
The perfusate usually contains red blood cells or oxygen carriers, nutrients, electrolytes, and medications like antibiotics, vasodilators (verapamil 0.25-0.5 mg/L), and anti-inflammatory agents. During perfusion, which can last 1-24 hours, clinicians monitor parameters including flow rates, vascular resistance, urine output, and biomarkers of injury to assess organ viability. This technique has shown particular benefit for marginal or extended criteria donor kidneys, with studies demonstrating reduced delayed graft function rates, improved early graft function, and potentially better long-term outcomes, as seen in the context of combined liver-kidney transplantation 1.
The physiological basis for these benefits includes maintenance of cellular energy stores, clearance of waste products, reduced oxidative stress, and preservation of endothelial function, all of which contribute to improved organ quality at transplantation. Although the provided evidence primarily focuses on liver machine perfusion 1 and combined liver-kidney transplantation 1, the principles of organ perfusion and the benefits of normothermic pulsatile perfusion can be applied to renal transplantation, prioritizing morbidity, mortality, and quality of life as the outcome.
Key considerations for normothermic pulsatile perfusion in renal transplantation include:
- Maintaining the organ at body temperature with oxygenated blood or a blood-based solution
- Monitoring parameters such as flow rates, vascular resistance, urine output, and biomarkers of injury to assess organ viability
- Using perfusate containing red blood cells or oxygen carriers, nutrients, electrolytes, and medications like antibiotics, vasodilators, and anti-inflammatory agents
- Perfusing the kidney for 1-24 hours to reduce ischemic injury and enable organ assessment before transplantation.
From the Research
Normothermic Pulsatile Perfusion in Renal Transplantation
- Normothermic perfusion is an alternative method of organ preservation that can improve the quality, resuscitate, assess, and potentially repair the organ 2.
- It has been demonstrated to be a feasible and well-tolerated method of organ preservation in a series of extended criteria donor kidneys 2.
- Normothermic perfusion can be used as a quality assessment tool for kidneys pretransplant, and may improve early graft function 2, 3.
- The use of normothermic ex vivo kidney perfusion (NEVKP) has shown promising results for preservation, assessment, and reconditioning of kidney allografts in preclinical studies 3.
- A study on NEVKP in human kidney transplantation found no differences in postoperative graft function, measured by serum creatinine, necessity for dialysis, and urine production, between the study group and the control group 3.
Pulsatile Perfusion of Kidney Allografts
- Pulsatile perfusion of kidney allografts is a technique used to preserve kidneys during organ preservation, and has been shown to be safe and lead to a decrease in delayed graft function, especially for marginal kidneys from extended criteria or deceased donors 4.
- The utilization of kidney pulsatile perfusion varies extensively throughout the USA, with rates of 7-12% in some institutions 4.
- A single center experience of outcomes in imported kidneys following normothermic regional perfusion (NRP) found that NRP was safe, and reduced rates of delayed graft function and improved early renal transplant function 5.
Protocols and Strategies for Normothermic Kidney Perfusion
- Normothermic machine perfusion (NMP) technologies are emerging as an important adjunct in organ preservation and transplantation, and can enable the reduction or avoidance of cold ischemia and allow for pretransplant measurement of function and metabolic status to assess the suitability of the organ for transplantation 6.
- There is no clear consensus on perfusion protocols, and different perfusate compositions, such as red blood cell-based solutions, artificial hemoglobin solutions, and acellular solutions, have been utilized in NMP 6.
- A period of NMP after hypothermic preservation is the most commonly used strategy, but alternative approaches, such as more prolonged periods of NMP, have also been developed and tested 6.