Heterotopic Porcine Cardiac Xenotransplantation in the Intra-Abdominal Position in a Non-Human Primate Model

Abstract

Heterotopic cardiac transplantation in the intra-abdominal position in a large animal model has been essential in the progression of the field of cardiac transplantation. Our group has over 10 years of experience in cardiac xenotransplantation with pig to baboon models, the longest xenograft of which survived over 900 days, with rejection only after reducing immunosuppression. This article aims to clarify our approach to this model in order to allow others to share success in long-term survival. Here, we demonstrate the approach to implantation of a cardiac graft into the intra-abdominal position in a baboon recipient for the study of transplantation and briefly highlight our model's ability to provide insight into not only xenotransplantation but across disciplines. We include details that have provided us with consistent success in this model; performance of the anastomoses, de-airing of the graft, implantation of a long-term telemetry device for invasive graft monitoring, and ideal geometric positioning of the heart and telemetry device in the limited space of the recipient abdomen. We additionally detail surveillance techniques to assess long-term graft function.

Figure 1

Intraabdominal placement of a cardiac xenograft with pressure telemetry monitor in the apex. IVC-inferior vena cava, Ao-Aorta, PA-pulmonary artery, EKG-electrocardiogram leads from telemetry device. Of note, whereas the telemetry device depicted here only has one pressure sensor and it is placed in the left ventricle at the apex, the pressure can be placed in the right atrium, pulmonary artery or aorta as well, depending on which hemodynamic parameters of interest are to be studied. Image Copyright: Tim Phelps JHU/AAMM, 2020.

Figure 2

Backtable preparation of the heart for transplantation. Ao-ascending aorta, PA-pulmonary artery, Pvv-Pulmonary vein common channel, Cava-superior and inferior vena caval junction. Image Copyright: Tim Phelps JHU/AAMM, 2020.

Figure 3

Aortic and Pulmonic Anastomosis to the Recipient. Abdomen. Image Copyright: Tim Phelps JHU/AAMM, 2020. Aortic and Pulmonic Anastomosis to the Recipient. Abdomen. Image Copyright: Tim Phelps JHU/AAMM, 2020.

Figure 4

Left ventricular thrombus in porcine xenograft.

Figure 5

Perfusion of Blood Through the Heterotopic Cardiac Graft: The graft is perfused via its coronary vessels during graft diastole and aortic valve cooptation, supplied from the recipient aorta. Perfused blood from the graft is then drained into the right atrium via the coronary sinus. Solid arrows denote recipient native blood flow. Dotted arrows represent graft blood flow in systole (outward from graft major vessels) and diastole (into graft atria/ventricles).