Flow-targeted pediatric ex vivo heart perfusion in donation after circulatory death: A porcine model

Background: The optimal blood flow and pressure to perfuse pediatric hearts from donation after circulatory death (DCD) on the ex vivo perfusion system has not been elucidated. This study sought to investigate the optimal perfusion strategy for pediatric DCD hearts by using a juvenile porcine model comparing pressure- vs flow-targeted strategy.

Methods: The hearts of the juvenile DCD pigs were explanted, and the coronary arteries were perfused for 2 hours by the ex vivo heart perfusion system with 2 different perfusion strategies; pressure-targeted perfusion (target coronary perfusion pressure: 40 mm Hg, group A) and flow-targeted perfusion (target coronary perfusion flow: 10 ml/kg/min, group B). The working model heart perfusion was used to assess systolic and diastolic myocardial performance.

Results: The body weight, warm and cold ischemic time, and ex vivo perfusion time were comparable between the groups. In the working model, group B showed significantly preserved cardiac output (A: 70.5 ± 15.3 ml/kg/min vs B: 113.8 ± 15.0 ml/kg/min, p < 0.01), stroke volume (A: 0.4 ± 0.1 ml/kg vs B: 0.7 ± 0.1 ml/kg, p < 0.01), and ejection fraction (A: 18.8% ± 5.9% vs B: 35.0% ± 10.6%, p < 0.01). E/e' and Tei index were also significantly preserved in group B. The percentage gain of heart weight after ex vivo (net increase of the heart weight divided by heart weight at baseline) was significantly smaller in group B (A: 20.0% ± 5.3% vs B: 11.6% ± 5.0%, p < 0.05). Troponin-I, myocardial hemorrhage, oxidative stress markers; myeloperoxidase and 8-hydroxy-2'-deoxyguanosine were also significantly lower after ex vivo perfusion in group B (p < 0.05).

Conclusions: The tightly controlled flow-targeted myocardial perfusion strategy for DCD donor hearts achieved better myocardial performance by causing less myocardial edema and limiting myocardial reperfusion injury.