Prolonged warm ischemia time and unsuccessful heart resuscitation with thoraco-abdominal normothermic regional...

Thoraco-abdominal normothermic regional perfusion (TA-NRP) is increasingly used to resuscitate organs donated following circulatory death (DCD). Its impact on lung grafts is unknown. This preclinical study assessed, via ex-vivo lung perfusion (EVLP), lungs retrieved after TA-NRP resuscitation across varying functional warm ischemic times (fWIT).

Pigs were subjected to fWITs of 15, 30, or 45 min after hypoxic cardiac arrest (n=4 per group), followed by 60 min of TA-NRP. A control group (n=4) underwent direct procurement (DP) after 30 min of fWIT. Lungs were cold-stored for one hour before EVLP evaluation. Lung function, gas exchange, hemodynamics, and inflammation were analyzed.

Cardiac resuscitation was successful for 15- and 30-minute fWITs, but not after 45 min. All lungs met ISHLT transplant criteria. However, WIT45 lungs showed higher pulmonary vascular resistance (aVR) (WIT45:673±95 dyn.s.cm⁻⁵, p=0.06), decreased compliance (WIT45:29±2 ml/cmH₂O, p=0.018) and increased weight gain (p=0.028), with significantly elevated pro-inflammatory cytokines. All metabolic profiles and gas exchange capacities remained stable.

Lungs recovered after ≤30 min fWIT and TA-NRP remain viable for transplantation. However, prolonged WIT with unsuccessful cardiac resuscitation may adversely impact lung function. Strategies to ensure safe lung procurement in the setting of DCD TA-NRP are needed, especially in the context of prolonged WIT.a.