819 Perioperative management in preclinical pig-to-baboon cardiac xenotransplantation
Wednesday November 18, 2015 from 15:30 to 17:00
Room 109

Jan-Michael Abicht, Germany



Ludwig Maximilian University


Perioperative management in preclinical pig-to-baboon cardiac xenotransplantation

Jan-Michael Abicht1, Tanja A Mayr2, Sonja Guethoff2, Fabian Werner2, Isabelle Lutzmann2, Paolo Brenner2, Bruno Reichart3.

1Department of Anaesthesiology, Ludwig-Maximilians University, Munich, Germany; 2Department of Cardiac Surgery, Ludwig-Maximilians University, Munich, Germany; 3Walter-Brendel-Centre, Ludwig-Maximilians University, Munich, Germany

Background: The outcome of life-supporting pig-to-baboon cardiac xenotransplantations is highly dependent on the anesthesiologic and perioperative treatment, which is in the experimental setting very demanding.

Methods: 27 pig (body weight 8 to 23 kg) to baboon (Papio anubis and Papio hamadryas; body weight 10 to 34 kg) cardiac xenotransplantations were performed with the use of cardiopulmonary bypass (CPB). 23 genetically modified hearts were transplanted using the heterotopic thoracic (htHTX) technique; four were transplanted orthotopically (oHTX). The baboons received a central venous catheter (18/18/16G) two days prior transplantation. After induction of a propofol-fentanyl based anesthesia the baboons received  an arterial line (20G) into the femoral artery. Cardiac output was measured using transpulmonary thermodilution. A specially designed, low priming volume (180ml) closed circuit heart lung machine was used during cardiac transplantation. After closure of the chest and before extubation an observation time of 3 to 4 hours was scheduled to rule out surgical bleeding and hemodynamic instability. During this time hemodynamic management was guided by transthoracic echocardiography. After removal of the femoral artery arterial blood pressure was monitored using an implanted telemetric system.

Results: Three times the experiment was terminated intraoperatively (air embolism, rupture of the aorta, surgical complication). In the rest of the htHTX and in all four oHTX the recipients could be weaned from CPB. During CPB a flow of 70-100% of baseline cardiac output was maintained. Up to 0.07 µg/kg/min of norepinephrine was used to preserve a minimal mean arterial pressure of 60 mmHg during CPB. In htHTX reperfusion time was kept to a minimum, in oHTX at least 60 minutes reperfusion time was given. In htHTX no inotropics were used, wheras in oHTX epinephrine (0.05 - 0.2 µg/kg/min) and dobutamin (0 – 4 µg/kg/min) had to be administered. In some cases of either group norepinephrine was used temporarily to increase arterial pressure to the target of 60-70 mmHg. Intraoperative blood loss could be compensated by transfusion of packed cells (4 packs of 30-40ml) to reach a postoperative hematocrit of 29 to 38%. No plasma or thrombocytes were transfused. After htHTX weaning from respirator was possible in 19/20 cases (one died because of a pneumothorax). After oHTX 2/4 baboons could be weaned from respirator. Central venous oxygenation was lower after oHTX (44 ±12 vs. 65±11%). After extubation oxygen was applied to the complete cage via an oxygen tent to increase inspiratory oxygen concentration.

Conclusion: The excellent 24h survival after life-supporting xenogenic cardiac transplantation confirms our perioperative strategies. Weaning from CPB and respirator are the biggest challenges, which are easier to overcome after htHTX. Nevertheless further improvements in the perioperative management are needed to improve the outcome of cardiac xenotransplantation in oHTX.

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