title: Mechanical support of the pressure overloaded right ventricle: an acute feasibility study comparing low and high flow support.
abstract: The objectives of this study were 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 right ventricular pressure overload. A Synergy Pocket Micro-pump (HeartWare International, Framingham, MA) 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 Blood was withdrawn from the right atrium to the pulmonary artery.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. 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, and ventricular capacitance) was successful, but with a concomitant and flow-dependent increase of the systolic afterload. This unloading diminished with right ventricular ischemia. Right ventricular mechanical support improves arterial blood pressure and cardiac output. It provides diastolic unloading of the right ventricle, but with a concomitant and right ventricular assist device flow-dependent increase of systolic afterload. These effects are most distinct 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 excessive increases in pulmonary artery pressure when pulmonary hypertension exists. This might protect against the development of pulmonary edema and hemorrhage.
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven and Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium; tom.verbelen@med.kuleuven.be.
authors.forename: Tom
authors.initials: T
authors.lastname: Verbelen
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven and Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium;
authors.forename: Jelle
authors.initials: J
authors.lastname: Verhoeven
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven and Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium;
authors.forename: Motohiko
authors.initials: M
authors.lastname: Goda
authors.affiliation: Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, New York; and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
authors.affiliation: Respiratory Division, University Hospitals Leuven and Department of Clinical and Experimental Medicine, University of Leuven, Leuven, Belgium.
authors.forename: Marion
authors.initials: M
authors.lastname: Delcroix
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven and Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium;
authors.forename: Filip
authors.initials: F
authors.lastname: Rega
authors.affiliation: Department of Cardiac Surgery, University Hospitals Leuven and Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium;
authors.forename: Bart
authors.initials: B
authors.lastname: Meyns
mesh_terms: D000818:Animals; D005240:Feasibility Studies; D006352:Heart Ventricles / Q000503:physiopathology*; D006439:Hemodynamics; D009200:Myocardial Contraction; D015425:Myocardial Reperfusion / Q000379:methods*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D012756:Sheep
keywords: mechanical support; partial support; pressure overloaded right ventricle