title: Physiologic effects of continuous-flow left ventricular assist devices.
abstract: Within the past 10 years, continuous-flow left ventricular assist devices (LVADs) have replaced pulsatile-flow LVADs as the standard of care for both destination therapy and bridging patients to heart transplantation. Despite the rapid clinical adoption of continuous-flow LVADs, an understanding of the effects of continuous-flow physiology, as opposed to more natural pulsatile-flow physiology, is still evolving.
  
  
  
  A thorough review of the relevant scientific literature regarding the physiological and clinical effects of continuous-flow physiology was performed. These effects were analyzed on an organ system basis and include an evaluation of the cardiovascular, respiratory, hematologic, gastrointestinal, renal, hepatic, neurologic, immunologic, and endocrine systems.
  
  
  
  Continuous-flow physiology is, generally speaking, well tolerated over the long term. However, several changes are manifest at the organ system level. Although many of these changes are without appreciable clinical significance, other changes, such as an increased rate of gastrointestinal bleeding, appear to be associated with continuous-flow physiology.
  
  
  
  Continuous-flow LVADs confer a significant advantage over their pulsatile-flow counterparts with regard to size and durability. From a physiological standpoint, continuous-flow physiology has limited clinical effects at the organ system level. Although improved over previous generations, challenges with this technology remain. Approaching these problems with a combination of clinical and engineering solutions may be needed to achieve continued progression in the field of durable mechanical circulatory support.
authors.affiliation: Department of Surgery, University of Utah, Salt Lake City, Utah.
authors.forename: Aaron H
authors.initials: AH
authors.lastname: Healy
authors.affiliation: Department of Surgery, University of Utah, Salt Lake City, Utah.
authors.forename: Stephen H
authors.initials: SH
authors.lastname: McKellar
authors.affiliation: Department of Medicine, University of Utah, Salt Lake City, Utah.
authors.forename: Stavros G
authors.initials: SG
authors.lastname: Drakos
authors.affiliation: Department of Surgery, University of Utah, Salt Lake City, Utah.
authors.forename: Antigoni
authors.initials: A
authors.lastname: Koliopoulou
authors.affiliation: Department of Medicine, University of Utah, Salt Lake City, Utah.
authors.forename: Josef
authors.initials: J
authors.lastname: Stehlik
authors.affiliation: Department of Surgery, University of Utah, Salt Lake City, Utah. Electronic address: craig.selzman@hsc.utah.edu.
authors.forename: Craig H
authors.initials: CH
authors.lastname: Selzman
mesh_terms: D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006353:Heart-Assist Devices / Q000009:adverse effects; D018056:Hemorheology; D006801:Humans; D016896:Treatment Outcome
keywords: Cardiac surgery; Heart failure; Left ventricular assist device; Mechanical circulatory support; Physiology