Right ventricular support for pulmonary arterial hypertension: an acute feasibility study in sheep

Purpose Mechanical support of the failing right ventricle (RV) can be a life-saving option in patients with pulmonary hypertension. Since the RV is very afterload dependent, this support can have unpredictable effects and is more likely to lead to RV dilatation. Therefore we wanted to assess the acute hemodynamic effects of RV support in different conditions of RV failure (RVF). Methods and Materials A Circulite TM Synergy TM micro-pump was inserted in adult sheep via a left thoracotomy. Blood was withdrawn from the right atrium to the pulmonary artery. Hemodynamic parameters were registered and pressure-volume loops were recorded at baseline and at 22000 RPM. To mimic different types of RVF, this procedure was performed in each animal 1) in control conditions (STANDARD), 2) after induction of pressure overload by banding the PA distal to the pump outflow (BANDING) and 3) after ligating the right coronary artery in these pressure overloaded sheep (BANDING + LIGATION). Results Changes in hemodynamics in the 3 different conditions are depicted in figure 1 . Comparable to the other two conditions, in the ischemic and pressure overloaded RV, contractility (reflected by dP/dt max , end systolic pressure volume relationship and preload recruitable stroke work) had a tendency to increase after starting the pump. Conclusions RV support in different types of RVF improves both systemic and pulmonary hemodynamics. Decreasing RV output and power, increasing total cardiac output and power and a stable central venous pressure reflect the successful unloading of the RV and good tolerance of this support. The pressure overloaded and ischemic failing RV improves since contractility remains preserved and since there is no increase in energetic need.