Large-Animal Model of Donation after Circulatory Death and Normothermic Regional Perfusion for Cardiac Assessment
Summary
The protocol describes a large-animal (porcine) model of donation after circulatory death, followed by thoracoabdominal normothermic regional perfusion that closely simulates the clinical scenario in heart transplantation, and has the potential to facilitate therapeutic studies and strategies.
Abstract
The increase in demand for cardiac transplantation throughout the years has fueled interest in donation after circulatory death (DCD) to expand the organ donor pool. However, the DCD process is associated with the risk of cardiac tissue injury due to the inevitable period of warm ischemia. Normothermic regional perfusion (NRP) allows for an in situ organ assessment, allowing the procurement of hearts determined to be viable. Here, we describe a clinically relevant large-animal model of DCD followed by NRP. Circulatory death is established in anesthetized pigs by stopping mechanical ventilation. After a preset warm ischemia period, an extracorporeal membrane oxygenator (ECMO) is used for a NRP period lasting at least 30 min. During this reperfusion period, the model allows the collection of various myocardial biopsies and blood samples for initial cardiac evaluation. Once NRP is weaned, biochemical, hemodynamic, and echocardiographic assessments of cardiac function and metabolism can be performed before organ procurement. This protocol closely simulates the clinical scenario previously described for DCD and NRP in heart transplantation and has the potential to facilitate studies aimed at decreasing ischemia-reperfusion injury and enhance cardiac functional preservation and recovery.
Introduction
Over 300,000 individuals die in North America each year of heart failure (HF); cardiac transplantation remains the only treatment option for some of these patients with end stage disease1. Historically, the exclusive source for heart transplantation was donor hearts obtained after neurological determination of death (NDD), but even then, only around 40% were adequate for transplantation2. Between 15% to 20% of patients die while waiting for a heart donation, with shortage of donor hearts being one of the reasons that creates a discrepancy between the hearts available and the hearts needed2. In order to increase the organ donor pool, one important consideration is the use of hearts donated after circulatory death (DCD)3. There is reluctance to use DCD hearts because these organs are invariably submitted to a period of unprotected (warm) ischemia after cessation of blood circulation and may sustain irreversible damage. Although reports for successful DCD heart transplantation with excellent early outcomes do exist4,5, there is a need to develop a validated assessment method to determine if these hearts are usable and to potentially predict their post-transplant performance6,7. To limit ischemic periods of DCD hearts and to continuously monitor them during storage and transportation, ex situ heart perfusion systems were developed8. However, this technology relies on complex machines with perfusion equipment, and has a high upfront cost without any guarantee that the procured organ will be suitable for transplantation. A novel protocol for DCD heart transplantation based on normothermic regional perfusion (NRP) was proposed by Messer et al3. This technique involves restoring myocardial perfusion while the heart is still in the donor and excluding cerebral circulation. It allows a functional assessment in situ before procurement3.
When using large-animal models, the porcine heart is one of the preferred platforms to perform cardiac surgical research considering its anatomical similarity to the human heart. However, some important factors in porcine hearts should be considered when using this model. For example, porcine cardiac tissue is very fragile and friable and is prone to tears, especially in the pulmonary artery and the right atrium9. Another important factor to consider is that the porcine heart is very sensitive to ischemia and prone to arrhythmias, which is why antiarrhythmics should be administered routinely to every animal before the experiment; nevertheless, it is still considered an appropriate model for the study of acute ischemia in heart transplantation9.
This manuscript describes a large-animal (porcine) model of donation after circulatory death followed by thoracoabdominal normothermic regional perfusion that closely simulates the clinical scenario in heart transplantation and has the potential to facilitate novel therapeutic studies and strategies for translational research.
Protocol
Representative Results
Discussion
This manuscript describes a large-animal model donation after circulatory death (DCD) followed by thoracoabdominal normothermic regional perfusion. In this experiment, the heart is reperfused for a minimum of 30 min and a maximum of 3 h before it is weaned off from the ECMO circuit. The heart is then functioning on its own for 2 h which allows for valuable cardiac assessment on the short term. Therefore, the major limitation of this protocol is the short-term follow-up; however, a long-term assessment would be resource-i…
Disclosures
The authors have nothing to disclose.
Acknowledgements
We would like to thank Melanie Borie, Caroline Landry, Henry Aceros and Ahmed Menaouar for their precious help and support.
Materials
| Amiodarone | As available in the institution | ||
| Angiocath 20G | BD | 381704 | |
| Atropine 0.4 mg/mL | As available in the institution | ||
| Biomedicus Centrifugal Pump | Medtronic | ||
| Cardioplegia Solution (Del Nido) | in-house made | Another solution can be used at the discretion of the researcher | |
| Cautery Pencil | Covidien | E2515H | |
| Central Venous Catheter double-lumen | Cook Medical | C-UDLM-501J-LSC | |
| Central Venous Sheath Introducer 7 Fr | |||
| Conductance Catheter | |||
| CPB pack | Medtronic | ||
| DLP Aortic Root Cannula | Medtronic | 12218 | |
| DLP double-stage venous cannula (29 or 37 F) | Medtronic | ||
| Dobutamine | As available in the institution | ||
| Dopamine | As available in the institution | ||
| Electrode Polyhesive | Covidien | E7507 | |
| EOPA Arterial Cannula (17 or 21 F) | |||
| Epinephrine | As available in the institution | ||
| O2 Face Mask | As available in the institution | ||
| Gloves, Nitrile, Medium | Fischer | 27-058-52 | |
| Heparin 1000 IU/mL | As available in the institution | ||
| Inhaled Isofurane | Provided by the institution's animal facility | ||
| Jelco 16 or 18 G catheter | |||
| Ketamine inj. 50 mL vial (100 mg/mL) | Health Canada | Health Canada approval is required | |
| Lidocaine/Xylocaine 1% | As available in the institution | ||
| Magnesium Sulfate 5 g/10 mL | As available in the institution | ||
| Midazolam inj. 10 mL vial (5 mg/mL) | Health Canada | Health Canada approval is required | |
| MPS Quest delivery disposable pack | Quest Medical | 5001102-AS | |
| Norepinephrine | As available in the institution | ||
| Normal Saline (NaCl 0.9%) 1L bag | Baxter | JB1324 | |
| Pipette Tips 1 mL | Fisherbrand | 02-707-405 | |
| Propofol 1 mg/mL | As available in the institution | ||
| Rocuronium | As available in the institution | ||
| Set Admin Prim NF PB W/ Checkvalve | Smith Medical | 21-0442-25 | |
| Sodium Bicarbonate (NaOH) 8.4% | As available in the institution | ||
| Sofsil 0 wax coated | Covidien | S316 | |
| Solumedrol 500 mg/5 mL | As available in the institution | ||
| Suction Tip | Covidien | 8888501023 | |
| Suction Tubing 1/4'' x 120'' | Med-Rx | 70-8120 | |
| Suture 3.0 Prolene Blu M SH | Ethicon | 8523H | |
| Suture 5.0 Prolene BB | Ethicon | 8580H | |
| Suture Prolene Blum 4-0 SH 36 | Ethicon | 8521H | |
| Suture BB 4.0 Prolene | Ethicon | 8881H | |
| Tracheal Tube, 6.5 mm | Mallinckrodt | 86449 | |
| Vasopressin | As available in the institution |
References
- Yusen, R. D., et al. The Registry of the International Society for Heart and Lung Transplantation: thirty-third adult heart transplantation report-2016; focus theme: primary diagnostic indications for transplant. The Journal of Heart and Lung Transplantation: the Official Publication of the International Society for Heart Transplantation. 35 (10), 1170-1184 (2016).
- Hornby, K., Ross, H., Keshavjee, S., Rao, V., Shemie, S. D. Non-utilization of hearts and lungs after consent for donation: a Canadian multicentre study. Canadian Journal of Anaesthesia. 53 (8), 831-837 (2006).
- Messer, S. J., et al. Functional assessment and transplantation of the donor heart after circulatory death. The Journal of Heart and Lung Transplantation: the Official Publication of the International Society for Heart Transplantation. 35 (12), 1443-1452 (2016).
- Messer, S., et al. Outcome after heart transplantation from donation after circulatory-determined death donors. The Journal of Heart and Lung Transplantation: the Official Publication of the International Society for Heart Transplantation. 36 (12), 1311-1318 (2017).
- Dhital, K. K., Chew, H. C., Macdonald, P. S. Donation after circulatory death heart transplantation. Current Opinion in Organ Transplantation. 22 (3), 189-197 (2017).
- Ardehali, A., et al. Ex-vivo perfusion of donor hearts for human heart transplantation (PROCEED II): a prospective, open-label, multicentre, randomised non-inferiority trial. The Lancet. 385 (9987), 2577-2584 (2015).
- White, C. W., et al. Assessment of donor heart viability during ex vivo heart perfusion. Canadian Journal of Physiology and Pharmacology. 93 (10), 893-901 (2015).
- Xin, L., et al. A new multi-mode perfusion system for ex vivo heart perfusion study. Journal of Medical Systems. 42 (2), 25 (2017).
- Robinson, N., et al., Iaizzo, P. A., et al. . Handbook of Cardiac Anatomy, Physiology, and Devices. , 469-491 (2015).
- Swindle, M. M. . Swine in the Laboratory: Surgery, Anesthesia, Imaging, and Experimental Techniques. , (2007).
- Nasir, B. S., et al. HSP90 inhibitor improves lung protection in porcine model of donation after circulatory arrest. The Annals of Thoracic Surgery. 110 (6), 1861-1868 (2020).
- Aceros, H., et al. Novel heat shock protein 90 inhibitor improves cardiac recovery in a rodent model of donation after circulatory death. The Journal of Thoracic and Cardiovascular Surgery. 163 (2), 187-197 (2022).
- Der Sarkissian, S., et al. Heat shock protein 90 inhibition and multi-target approach to maximize cardioprotection in ischaemic injury. British Journal of Pharmacology. 177 (15), 3378-3388 (2020).
- Aceros, H., et al. Celastrol-type HSP90 modulators allow for potent cardioprotective effects. Life Sciences. 227, 8-19 (2019).
- Aceros, H., et al. Pre-clinical model of cardiac donation after circulatory death. Journal of Visualized Experiments. (150), e59789 (2019).
- Der Sarkissian, S., et al. Celastrol protects ischaemic myocardium through a heat shock response with up-regulation of haeme oxygenase-1. British Journal of Pharmacology. 171 (23), 5265-5279 (2014).
