title: Right ventricular assist device in end-stage pulmonary arterial hypertension: insights from a computational model of the cardiovascular system.
abstract: BACKGROUND
  The high mortality rate of pulmonary arterial hypertension (PAH) mainly relates to progressive right ventricular (RV) failure. With limited efficacy of medical therapies, mechanical circulatory support for the RV has been considered. However, there is lack of understanding of the hemodynamic effects of mechanical support in this setting.
  
  
  METHODS
  We modeled the cardiovascular system, simulated cases of PAH and RV dysfunction and assessed the theoretical effects of a continuous flow micro-pump as an RV assist device (RVAD). RVAD inflow was sourced either from the RV or RA and outflow was to the pulmonary artery. RVAD support was set at various flow rates and additional simulations were carried out in the presence of atrial septostomy (ASD) and tricuspid regurgitation (TR).
  
  
  RESULTS
  RVAD support increased LV filling, thus improving cardiac output and arterial pressure, unloading the RA and RV, while raising pulmonary arterial and capillary pressures in an RVAD flow-dependent manner. These effects diminished with increasing disease severity. The presence of TR did not significantly impact the hemodynamic effects of RVAD support. ASD reduced the efficacy of RVAD support, since right-to-left shunting decreased and ultimately reversed with increasing RVAD support due to the progressive drop in RA pressure.
  
  
  CONCLUSIONS
  The results of this theoretical analysis suggest that RVAD support can effectively increase cardiac output and decreases RA pressure with the consequence of increasing pulmonary artery and capillary pressures. Especially in advanced PAH, low RVAD flow rates may mitigate these potentially detrimental effects while effectively increasing systemic hemodynamics.
authors.affiliation: Division of Cardiology, Weill Cornell Medical College, New York, NY, USA. punnoosl@alum.mit.edu
authors.forename: Lynn
authors.initials: L
authors.lastname: Punnoose
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
authors.forename: Stuart
authors.initials: S
authors.lastname: Rich
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Horn
mesh_terms: D065627:Familial Primary Pulmonary Hypertension; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006353:Heart-Assist Devices; D006801:Humans; D006976:Hypertension, Pulmonary / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D008955:Models, Cardiovascular; D018497:Ventricular Dysfunction, Right / Q000150:complications / Q000503:physiopathology / Q000628:therapy*