title: Hemodynamic effects of partial ventricular support in chronic heart failure: results of simulation validated with in vivo data.
abstract: OBJECTIVE
  Current left ventricular assist devices are designed to provide full hemodynamic support for patients with end-stage failing hearts, but their use has been limited by operative risks, low reliability, and device-related morbidity. Such concerns have resulted in minimum use of left ventricular assist devices for destination therapy. We hypothesize that partial circulatory support, which could be achieved with small pumps implanted with less-invasive procedures, might expand the role of circulatory support devices for treatment of heart failure.
  
  
  METHODS
  We examine the hemodynamic effects of partial left ventricular support using a previously described computational model of the cardiovascular system. Results from simulations were validated by comparison with an in vivo hemodynamic study.
  
  
  RESULTS
  Simulations demonstrated that partial support (2-3 L/min) increased total cardiac output (left ventricular assist device output plus native heart output) by more than 1 L/min and decreased left ventricular end-diastolic pressure by 7 to 10 mm Hg with moderate-to-severe heart failure. Analyses showed that the hemodynamic benefits of increased cardiac output and decreased left ventricular end-diastolic pressure are greater in less-dilated and less-dysfunctional hearts. Both the relationships between ventricular assist device flow and cardiac output and ventricular assist device flow and left atrial pressure predicted by the model closely approximated the same relationships obtained during hemodynamic study in a bovine heart failure model.
  
  
  CONCLUSIONS
  Results suggest that a pump with a flow rate of 2 to 3 L/min could meaningfully affect cardiac output and blood pressure in patients with advanced compensated heart failure. The development of small devices capable of high reliability and minimal complications that can be implanted with less-invasive techniques is supported by these findings.
authors.affiliation: Department of Clinical Affairs, CircuLite, Inc, Hackensack, NJ 07601, USA. dmorley@circulite.net
authors.forename: Deborah
authors.initials: D
authors.lastname: Morley
authors.forename: Kenneth
authors.initials: K
authors.lastname: Litwak
authors.forename: Paul
authors.initials: P
authors.lastname: Ferber
authors.forename: Paul
authors.initials: P
authors.lastname: Spence
authors.forename: Robert
authors.initials: R
authors.lastname: Dowling
authors.forename: Bart
authors.initials: B
authors.lastname: Meyns
authors.forename: Bartley
authors.initials: B
authors.lastname: Griffith
authors.forename: Daniel
authors.initials: D
authors.lastname: Burkhoff
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002302:Cardiac Output; D002320:Cardiovascular Physiological Phenomena; D002417:Cattle; D003198:Computer Simulation; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D017725:Ventricular Pressure