Introduction: Increasing use of donors after cardiac death (DCD) lead to a new interest in the organ perfusion. Sometimes in case of unavailability of multiple systems for organ perfusion or in case of contemporary multiple donors some organ could be statically cold stored instead than perfused possibly determining impaired function. Here we present an hypothermic oxygenated machine perfusion applied to an en-bloc dual kidney retrieved from an animal (pig) DCD model.

Method: After the pig was dead, the abdominal organs bloc was retrieved. Organs were separated and the bloc, composed by kidneys, aorta and inferior vena cava was prepared at the back-table and perfused with heparinized (10.000UI) perfusion solution (Celsior 1l). The back-table surgery consisted in the ligation of collateral branches from aorta and inferior vena cava, ligation of perirenal fat, proximal aortic stump ligation and distal aortic stump cannulation (Fig 1a). The perfusion was performed with PerKidney machine perfusion (PerLife, Aferetica s.r.l, Bologna, Italy). During the hypothermic oxygenated perfusion was set a target pressure (P) of 50 mmHg and a target flow (F) of 100ml/min. Normothermic perfusion, as a simulation of transplant, was performed setting a target P of 75 mmHg and a target F of 500ml/min.

Results: The no-flow period lasted 35min, back-table surgery lasted 27.5 ±3.5 min. The hypothermic perfusion lasted 110 min: the mean temperature (T) during perfusion was 6.8 ±1.4 °C, the mean F was 120.4 ±58.7 ml/min, the mean P was 40.3 ±11.2 mmHg and the mean resistance (R) was 0.37 ±0.26 mmHg/ml/min. R started at 1.07, dropped down after 55min concluded at 0.06. Parameters during hypothermic perfusion are reported in figure2a. The normothermic perfusion lasted 49 min: the mean T was 35.3 ±1.5 °C, the mean F was 495 ±11 ml/min, the mean P was 18 ±8 mmHg and the mean R was 0.031 ±0.016 mmHg/ml/min. R started at 0.05, dropped down after 10 min and concluded at 0.01. During the perfusion kidneys gradually changed in color (Fig 1b-1c). Parameters during normothermic perfusion are reported in figure2.

Conclusion: In this preliminary proof of concept on a large animal model the dual kidney en-bloc perfusion appears feasible. The decreasing of R, the maintenance of F and P, changing in color are favorable characteristics supporting this option, potentially useful in case of lack of devices and contemporary donations. Larger experience is needed for a better setting of parameters during the perfusion and surgical technique.