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MECHANICAL SUPPORT OF THE PRESSURE OVERLOADED RIGHT VENTRICLE: AN ACUTE FEASIBILITY STUDY COMPARING LOW AND HIGH FLOW SUPPORT
Journal Contribution - Journal Article
Objective To assess the feasibility of low flow right ventricular support, and to describe the hemodynamic effects of low versus high flow support in an animal model of acute RV pressure overload. Methods A Synergy Pocket Micro-pump (HeartWare International, Framingham MA, USA) was implanted in seven sheep. Blood was withdrawn from the right atrium to the pulmonary artery. Hemodynamics and pressure-volume loops were recorded in baseline conditions, after banding the pulmonary artery, and after ligating the right coronary artery in these banded sheep. Results End-organ perfusion (reflected by total cardiac output and arterial blood pressure) improved in all conditions. Intrinsic right ventricular contractility was not significantly impacted by support. Diastolic unloading of the pressure overloaded right ventricle (reflected by decreases in central venous pressure, end-diastolic pressure and volume, ventricular capacitance and chamber stiffness) was successful, but with a concomitant and flow-dependent increase of the systolic afterload. This unloading diminished with right ventricular ischemia. Conclusions Right ventricular mechanical support leads to an improved end-organ perfusion and a successful diastolic right ventricular unloading, most distinctly in the pressure overloaded right ventricle without profound ischemic damage. We advocate the low flow strategy which is potentially beneficial for the afterload sensitive right ventricle and has the advantage of avoiding a too excessive increase in pulmonary artery pressure when pulmonary hypertension exists. This might protect against the development of pulmonary edema and hemorrhage.
Journal: American Journal of Physiology - Heart and Circulatory Physiology
Pages: H615 - H624
Number of pages: 10