Evaluation of target temperature on effectiveness of myocardial preservation during hypothermic machine perfusion

Abstract

Background: Ex-situ heart perfusion (ESHP) has been proposed as an optimal method for preserving donated hearts prior to transplantation. Hypothermic oxygenated perfusion (HOP) is a simple method from a device design perspective, with enhanced safety compared to normothermic perfusion in the event of device failure. However, the optimal temperature for cardiac HOP has yet to be determined. We evaluated the effectiveness of 12-hour HOP using University of Wisconsin Machine Perfusion Solution (UWMPS) in different temperatures compared to static cold storage (SCS) for 6 hours followed by simulated transplantation. Additionally, we sought to determine the impact of oxygen supplementation in hypothermic ESHP in the heart function preservation. Methods: Hearts were procured from Yorkshire pigs (n=35) randomized into 3 preservation therapies: 6hours-SCS; 12hours-HOP and 12 hours hypothermic non-oxygenated perfusion (HNOP-without oxygen supplementation). For either HOP or HNOP groups, 3 temperatures were tested (5°C; 10°C; 15°C). After the preservation period, hearts had their function assessed in a normothermic perfusion machine capable of working mode, simulating transplantation. Results: All perfusion parameters were stable throughout (mean±SD): aortic flow 65±5.57 ml/min, aortic pressure: 11.51±3.17 mmHg. All HOP hearts presented a better cardiac index than SCS (p<0.05). The HNOP hearts presented similar cardiac function results compared to SCS. Conclusions: HOP for 12 hours had better heart function preservation than SCS for 6 hours. Even HNOP had similar results compared to SCS. Greater edema formation in ESHP hearts did not affect heart function. Hypothermic ESHP safely enhances function preservation compared to SCS.

Keywords

• ex-situ heart perfusion
• heart transplantation
• myocardial preservation
• hypothermic machine perfusion
• organ preservation