Pulsed Perfusion for Marginal Kidneys

Trends in organ donor pool are characterized by an increasing age and a shift towards cerebrovascular diseases as primary causes of death. As a result, donors older than 60 years nowadays represent more than one fourth of the entire donor pool in Italy. This, along with an increasing number of patients on the waiting list for transplantation, prompted a growing use of organs from subjects older than 60 years that would have been considered unsuitable years ago. To improve graft outcomes, transplant of two older kidneys in the same recipient has been proposed. To optimize allocation of these organs to single or dual transplantation,a scoring system for kidneys, based on biopsy, with scores ranging from a minimum of 0 (indicating the absence of renal lesions) to a maximum of 12 (indicating the presence of marked changes in the renal parenchyma) has been suggested. According to this panel, kidneys with a score of 4 or lower are predicted to contain enough viable nephrons to be used as single transplants, those with a score of 5, 6, or 7 can be used as dual transplants, kidneys with a score greater than 7 are discarded. The survival of kidney grafts obtained from donors older than 60 years and allocated for single or dual transplantation on the basis of biopsy findings before transplantation was similar to that of single grafts from younger donors. To further improve these results, set-up of strategies to preserve organs is crucial to save the residual nephron mass and optimize outcomes of these marginal grafts. In this regard, over the past 30 years two methods of kidney preservation have been developed. With cold storage, the kidney is flushed once it is removed from the donor and placed in an ice-cooled container with preservation solution. With the use of pulsatile machine perfusion, the kidney is connected to a machine, which pumps a cold solution containing oxygen and nutrients through the kidney. This process allows for metabolism to continue in the kidney with end products being removed. The broad aim of the present study is to evaluate whether pulsatile machine perfusion of kidneys from older/marginal donors may provide better outcomes than static perfusion. To this purpose the outcome of recipients of perfused kidneys will be compared with the outcome of historical controls receiving non-perfused kidney selected and allocated on the basis of the same criteria and matched by gender, age and kidney histologic score.