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Eur J Cardiothorac Surg. 2016 Jan;49(1):25-31. doi: 10.1093/ejcts/ezv066. Epub 2015 Mar 3.

Moderate hypothermia during ex vivo machine perfusion promotes recovery of hearts donated after cardiocirculatory death†.

Author information

1
Department of Cardiovascular Surgery, University Hospital Zürich, Zurich, Switzerland herman.tolboom@usz.ch.
2
Department of Physiology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.
3
Department of Cardiovascular Surgery, University Hospital Zürich, Zurich, Switzerland.
4
Department of Paediatric Cardiology, Children's Hospital Zürich, Zurich, Switzerland.
5
Institute of Veterinary Physiology, Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.

Abstract

OBJECTIVES:

To establish the optimal machine perfusion temperature for recovery of hearts in a rodent model of donation after declaration of cardiocirculatory death (DCD).

METHODS:

Hearts from male Lewis rats (n = 14/group) were subjected to 25 min of in situ warm (37°C) ischaemia to simulate DCD. They were then explanted and reperfused with diluted autologous blood for 60 min at 20, 25, 30, 33 or 37°C, after which they were stored at 0-4°C in Custodiol preservation solution for 240 min. Fresh-excised and cold-stored ischaemic hearts were used as controls. The viability of the different groups was assessed by comparing heart rate and left ventricular contractility in a Langendorff circuit, as well as perfusate levels of troponin-t and creatine kinase (CK), and myocardial levels of adenosine triphosphate (ATP) and reduced glutathione.

RESULTS:

During ex vivo reperfusion, hearts in all groups resumed beating within minutes. The mean heart rate was highest in the 37°C group at 154.72 ± 33.01 beats × min(-1) (bpm), and declined in proportion to temperature to 39.72 ± 5.53 bpm at 20°C. Troponin-t levels were highest in the 37°C group (79.49 ± 20.79 µg/l), the values were significantly lower in all other reconditioned groups with a minimum of 12.472 ± 7.08 µg/l in the 20°C group (P < 0.0001). Tissue ATP levels ranged from 4.32 ± 1.71 µmol/g at 33°C to 4.59 ± 1.41 µmol/g at 30°C, all significantly higher than the mean ATP level of 1.41 ± 0.93 µmol/g in untreated ischaemic hearts (P < 0.0001). During Langendorff assessment, the mean heart rate and contractility of all groups were higher than those of cold-stored ischaemic hearts (P < 0.0001), yet not significantly different from those of fresh controls. The perfusate levels of troponin-t and CK, and myocardial levels of reduced-glutathione and ATP were not significantly different between groups.

CONCLUSION:

Our results suggest that mild hypothermia during ex vivo reperfusion improves recovery of ischaemic hearts in a rodent DCD model.

KEYWORDS:

Declaration of cardiocirculatory death; Heart transplantation; Ischaemia-reperfusion; Machine perfusion; Organ preservation

PMID:
25740820
DOI:
10.1093/ejcts/ezv066
[Indexed for MEDLINE]

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