In vivo evaluation of the HeartWare MVAD Pump.
OBJECTIVE
The current design trend for left ventricular assist devices (LVADs) is miniaturization, which aims to increase the treatable patient population and enable new treatment indications by reducing surgical trauma and the complications associated with device implantation. The MVAD Pump (HeartWare Inc, Framingham, MA) is a small, axial VAD that uses magnetic and hydrodynamic impeller technology and incorporates wide helical flow channels to minimize shear stress. In this study, we implanted the MVAD Pump in an ovine model to evaluate device hemocomaptiblity, biocompatibility, performance, and safety.


METHODS
The MVAD Pump was implanted in an ovine model (n = 9) for 90 days. The pump was implanted through a thoracotomy and secured to the LV apex with a gimbaled sewing ring, which allowed for intraoperative adjustment of the insertion depth and angle of the inflow cannula. Serum analytes and coagulation parameters were analyzed at specific intervals throughout the study period. Pump flow, speed, and power were recorded daily to monitor device performance. Sheep were electively euthanized at 90 days for pathologic and histologic analysis.


RESULTS
In this study, results demonstrated the safety, reliability, hemocompatability, and biocompatibility of the MVAD Pump. Nine animals were implanted for 90 ± 5 days. No complications occurred during surgical implantation. Seven of the 9 animals survived until elective sacrifice. Each sheep that survived to the scheduled explant appeared physically normal, with no signs of cardiovascular or other organ compromise. The 2 sheep that were euthanized early showed no evidence of device-related issues.


CONCLUSIONS
The MVAD Pump was successfully implanted through a thoracotomy and demonstrated excellent hemodynamic support with no device malfunctions throughout the study period.
Bluhm Cardiovascular Institute, Northwestern Memorial Hospital, Northwestern University School of Medicine, Chicago, Illinois. Electronic address: emcgee@nmh.org.
Edwin
E
McGee
HeartWare Inc, Framingham, Massachusetts.
Katherine
K
Chorpenning
HeartWare Inc, Framingham, Massachusetts.
Michael C
MC
Brown
BioSurg Inc, Winters, California.
Eugene
E
Breznock
HeartWare Inc, Framingham, Massachusetts.
Jeffrey A
JA
Larose
HeartWare Inc, Framingham, Massachusetts.
Daniel
D
Tamez
D000818:Animals; D020878:Device Removal; D006353:Heart-Assist Devices; D006439:Hemodynamics / Q000502:physiology; D006452:Hemoglobinometry; D008422:Materials Testing; D008904:Miniaturization / Q000295:instrumentation*; D023421:Models, Animal; D011474:Prosthesis Design; D012756:Sheep
HeartWare; LVAD; MCS; MVAD pump; heart failure; miniaturization