First Expierence in Heart Transplantation with Organs Procured after Cardio-Circulatory Death in a Porcine Model. Is the Organ Care System the Long Awaited Solution?

Abstract

Objectives: Donation after cardiac death (DCD) has lead to an increase in organ availability. For obvious reasons, DCD hearts could not be used for transplantation. Several scenarios have been suggested in which DCD hearts could be used, most involving the re-establishing of blood flow within the donor by a variety of means. This leads to enormous ethical challenges based on the physiological situation within the donor. We propose to procure the heart alongside the other organs in a standard manner followed by an ex vivo assessment and reconditioning using the Organ Care System (OCS). The OCS is a mobile unit which allows for preservation and transport of a continuously perfused, beating heart, thereby avoiding the effects of cold ischemic storage and providing further assessment options, which is used in clinical transplantation for extended criteria donors by us. Methods: The study protocol reflects the UK's current clinical DCD protocol and practice. 5 pigs were anaesthetized with isofluorane. No heparin was administered. Cardio circulatory death was induced by cessation of mechanical ventilation. Agonal time (AT) was calculated as the time between a reduction of blood pressure below 50 mm Hg or a fall in saturation beneath 70% and the cessation of electrical activity. After a further 15 minute. of warm ischemia, hearts were procured and implanted into the OCS, mimicking the actual clinical scenario for other organs. Thus procured grafts were reconditioned in the OCS and assessed over a period of 4 hour. Results: 4 hearts were successfully resuscitated in the system (AT 8, 15, 20 and 34 minute.) with an overall time from withdrawal to OCS perfusion (WtP) of 41, 50, 67and 79 minute., respectively. ¾ had excellent contractility and lactate trends and were considered to be transplantable. ¼ (AT 34 minute, WtP 79 minute.) had an increased lactate and abnormal contractility being unsuitable for transplantation. One heart with 48 minute. AT and a WtP of 90 minute. could not be resuscitated. Conclusions: Our data show that hearts from not heparinized, DCD donors can be successfully reconditioned using the OCS in a scenario simulating actual clinical conditions. Based on the results we plan to assess the model in a clinical DCD environment.