title: Real-time adjustment of ventricular restraint therapy in heart failure.
abstract: OBJECTIVE
  Current ventricular restraint devices do not allow for either the measurement or adjustment of ventricular restraint level. Periodic adjustment of restraint level post-device implantation may improve therapeutic efficacy. We evaluated the feasibility of an adjustable quantitative ventricular restraint (QVR) technique utilizing a fluid-filled polyurethane epicardial balloon to measure and adjust restraint level post-implantation guided by physiologic parameters.
  
  
  METHODS
  QVR balloons were implanted in nine ovine with post-infarction dilated heart failure. Restraint level was defined by the maximum restraint pressure applied by the balloon to the epicardium at end-diastole. An access line connected the balloon lumen to a subcutaneous portacath to allow percutaneous access. Restraint level was adjusted while left ventricular (LV) end-diastolic volume (EDV) and cardiac output was assessed with simultaneous transthoracic echocardiography.
  
  
  RESULTS
  All nine ovine successfully underwent QVR balloon implantation. Post-implantation, restraint level could be measured percutaneously in real-time and dynamically adjusted by instillation and withdrawal of fluid from the balloon lumen. Using simultaneous echocardiography, restraint level could be adjusted based on LV EDV and cardiac output. After QVR therapy for 21 days, LV EDV decreased from 133+/-15 ml to 113+/-17 ml (p<0.05).
  
  
  CONCLUSIONS
  QVR permits real-time measurement and physiologic adjustment of ventricular restraint therapy after device implantation.
authors: Division of Cardiac Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
authors: Ravi K
authors: RK
authors: Ghanta
authors: Lawrence S
authors: LS
authors: Lee
authors: Ramanan
authors: R
authors: Umakanthan
authors: Rita G
authors: RG
authors: Laurence
authors: John A
authors: JA
authors: Fox
authors: Ralph Morton
authors: RM
authors: Bolman
authors: Lawrence H
authors: LH
authors: Cohn
authors: Frederick Y
authors: FY
authors: Chen
mesh_terms: D000818:Animals; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures / Q000295:instrumentation / Q000379:methods*; D004452:Echocardiography; D005240:Feasibility Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D008297:Male; D023421:Models, Animal; D012756:Sheep; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000601:surgery