title: Transapical miniaturized ventricular assist device: design and initial testing.
abstract: BACKGROUND
  Left ventricular assist devices are increasingly used to treat patients with advanced and otherwise refractory heart failure as bridge to transplant or destination therapy. We evaluated a new miniaturized left ventricular assist device that requires minimal surgery for implantation, potentially allowing implantation in earlier stage heart failure.
  
  
  METHODS
  HeartWare (Miami Lakes, Fla) developed transapical miniaturized ventricular assist device. Acute (n = 4), 1-week (n = 2), and 30-day (n = 4) bovine model experiments evaluated hemodynamic efficacy and biocompatibility of the device, which was implanted through small left thoracotomy with single insertion at apex of left ventricle without cardiopulmonary bypass. The device outflow cannula was positioned across the aortic valve. The international normalized ratio was maintained between 2.0 and 2.5 with warfarin. Hemodynamic, echocardiographic, fluoroscopic, hematologic, and blood chemistry measurements were evaluated.
  
  
  RESULTS
  The device was successfully implanted through the left ventricular apex in all 10 animals. The device was operated at 15,000 ± 1000 rpm (power consumption, 3.5-6.0 W). The device maintained normal end-organ perfusion with no significant hemolysis (0-30 mg/dL). There were no pump failures or device-related complications. At autopsy, no abnormalities were seen in endocardium, aortic valve leaflets, or aortic root. There was no evidence of thromboembolism or abnormalities in any peripheral end organs.
  
  
  CONCLUSIONS
  We successfully demonstrated feasibility of a novel intraventricular assist device that can be completely implanted through left ventricular apex. This transapical surgical approach eliminates needs for sternotomy, device pocket, cardiopulmonary bypass, ventricular coring, and construction of an outflow graft anastomosis.
authors.affiliation: Department of Surgery, Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40202, USA. mark.slaughter@louisville.edu
authors.forename: Mark S
authors.initials: MS
authors.lastname: Slaughter
authors.forename: Guruprasad A
authors.initials: GA
authors.lastname: Giridharan
authors.forename: Dan
authors.initials: D
authors.lastname: Tamez
authors.forename: Jeff
authors.initials: J
authors.lastname: LaRose
authors.forename: Mike A
authors.initials: MA
authors.lastname: Sobieski
authors.forename: Leslie
authors.initials: L
authors.lastname: Sherwood
authors.forename: Steven C
authors.initials: SC
authors.lastname: Koenig
mesh_terms: D000818:Animals; D002417:Cattle; D004867:Equipment Design; D006352:Heart Ventricles; D006353:Heart-Assist Devices; D008297:Male; D008904:Miniaturization; D023421:Models, Animal; D019919:Prosthesis Implantation / Q000379:methods*