title: The reservoir-wave approach to characterize pulmonary vascular-right ventricular interactions in humans.
abstract: Using the reservoir-wave approach (RWA) we previously characterized pulmonary vasculature mechanics in a normal canine model. We found reflected backward-traveling waves that decrease pressure and increase flow in the proximal pulmonary artery (PA). These waves decrease right ventricular (RV) afterload and facilitate RV ejection. With pathological alterations to the pulmonary vasculature, these waves may change and impact RV performance. Our objective in this study was to characterize PA wave reflection and the alterations in RV performance in cardiac patients, using the RWA. PA pressure, Doppler-flow velocity, and pulmonary arterial wedge pressure were measured in 11 patients with exertional dyspnea. The RWA was employed to analyze PA pressure and flow; wave intensity analysis characterized PA waves. Wave-related pressure was partitioned into two components: pressures due to forward-traveling and to backward-traveling waves. RV performance was assessed by examining the work done in raising reservoir pressure and that associated with the wave components of systolic PA pressure. Wave-related work, the mostly nonrecoverable energy expended by the RV to eject blood, tended to vary directly with mean PA pressure. Where PA pressures were lower, there were pressure-decreasing/flow-increasing backward waves that aided RV ejection. Where PA pressures were higher, there were pressure-increasing/flow-decreasing backward waves that impeded RV ejection. Pressure-increasing/flow-decreasing backward waves were responsible for systolic notches in the Doppler flow velocity profiles in patients with the highest PA pressure. Pulmonary hypertension is characterized by reflected waves that impede RV ejection and an increase in wave-related work. The RWA may facilitate the development of therapeutic strategies.
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: Anukul
authors.initials: A
authors.lastname: Ghimire
authors.affiliation: Department of Cardiology, University of Aarhus, Aarhus, Denmark; and.|Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic Rochester, Rochester, Minnesota.
authors.forename: Mads J
authors.initials: MJ
authors.lastname: Andersen
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Burrowes
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Bouwmeester
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Grant
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: Israel
authors.initials: I
authors.lastname: Belenkie
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada.
authors.forename: Nowell M
authors.initials: NM
authors.lastname: Fine
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic Rochester, Rochester, Minnesota.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Borlaug
authors.affiliation: Department of Cardiac Sciences, Cumming School of Medicine, University of Calgary, and the Libin Institute of Cardiovascular Research, Calgary, Alberta, Canada; jtyberg@ucalgary.ca.
authors.forename: John V
authors.initials: JV
authors.lastname: Tyberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology; D008297:Male; D011651:Pulmonary Artery / Q000503:physiopathology; D011669:Pulmonary Wedge Pressure / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*
keywords: Doppler echocardiography; heart failure; hemodynamics; wave intensity analysis