Improvement of Left but Not Right Ventricular Contractility after Circulatory Death and Normothermic Regional Perfusion in a Porcine Model

Abstract

Purpose To investigate the impact of cerebral reperfusion on cardiac contractile function after normothermic regional perfusion (NRP) after anoxic circulatory death in a porcine model. Methods The animals were anaesthetized and biventricular pressure-volume catheters and a pulmonary artery catheter were inserted percutaneously. Through a midline sternotomy, the heparinised animals were cannulated for extracorporeal circulation. Baseline data were obtained before cessation of mechanical ventilation. Death was determined 5 minutes after mechanical asystole and after additional 3 minutes of warm ischemia NRP was started using a heart-lung machine. The animals were randomized before reperfusion to either clamping (CL) (n=8) or non-clamping (NCL) (n=8) of the aortic arch vessels; the infrarenal aorta was clamped in both groups. The NRP-protocol includes early volume loading of the right ventricle, infusion of dobutamine and norepinephrine and gradual wean over 30 minutes. The animals were observed for 180 minutes after weaning from NRP. Results All animals were successfully weaned from NRP. Both groups demonstrated an acceptable cardiac function after weaning with a mean arterial blood pressure above 75 mmHg and low filling pressures. The NCL group received significantly more norepinephrine (p=0.0484) than the CL group. The left ventricle End-systolic pressure-volume relationship as an index of contractility showed improvement in both groups after wean from NRP compared to baseline (p=0.0009). In the CL group, LV contractility showed a tendency to a better improvement compared to the NCL group (p=0.226) (Fig. 1). The RV showed preserved contractility in both groups. Conclusion LV contractility but not RV contractility improves after circulatory death and weaning from NRP. The improvement of the left ventricular contractility tends to be better when the aortic arch vessels are clamped compared to upper-body perfusion.