Current status on the development of a totally implantable biventricular assist device: the Baylor Gyro BVAD.
OBJECTIVE
The Baylor Gyro BVAD is under development with the final goal of establishing a totally implantable biventricular assist system (BVAD). The aim of this study was to evaluate the safety, reliability, and effectiveness of the device in a long-term in vivo model.


METHODS
The BVAD was implanted into eight calves for longer than 4 weeks in a biventricular bypass fashion, with the native heart remaining. Pump performance was assessed with the system's digital data acquisition unit. Postoperatively, anticoagulation was maintained with i.v. heparin perfusion (ACT< or = 250 sec) gradually replaced by coumadin. Treadmill exercise tests were performed daily following a 10-day reconvalescence period after surgery.


RESULTS
The animals were kept alive for 37-90 days. The pumps yielded average flows of 5.3 +/- 1.1 l/min and 4.9 +/- 0.7 l/min for the LVAD and RVAD, respectively. Power consumption was 8.2 +/- 2.7 W and 9.6 +/- 4.7 W at 1935 +/- 123 rpm and 2015 +/- 365 rpm, respectively. All cases exhibited low hemolysis; renal and liver function were kept normal throughout the experiments. The animals demonstrated no thromboembolic neurological symptoms and tolerated moderate treadmill exercise.


CONCLUSIONS
The Baylor Gyro BVAD demonstrated effective and reliable in vivo performance with acceptable biocompatibility. Based on these studies, we conclude that the system will be suitable as a long-term totally implantable BVAD for uses intended for longer than two years.
Klinik für kardiovaskuläre Chirurgie, Universitätsklinikum Charité der Humboldt-Universität zu Berlin, Berlin, Germany. joerg.linneweber@charite.de
J
J
Linneweber
K
K
Nonaka
S
S
Ichikawa
H
H
Ishitoya
T
T
Motomura
Y
Y
Nosé
D000818:Animals; D015415:Biomarkers / Q000097:blood; D002302:Cardiac Output / Q000502:physiology; D002417:Cattle; D003404:Creatinine / Q000097:blood; D004867:Equipment Design / Q000295:instrumentation*; D004869:Equipment Safety / Q000295:instrumentation; D005080:Exercise Test; D005337:Fibrin / Q000378:metabolism; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000601:surgery; D006353:Heart-Assist Devices; D020007:Implants, Experimental; D023421:Models, Animal; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology; D011183:Postoperative Complications / Q000209:etiology; D019919:Prosthesis Implantation; D012016:Reference Values; D012039:Regional Blood Flow / Q000502:physiology; D016896:Treatment Outcome; D016276:Ventricular Function
D015415:Biomarkers; D005337:Fibrin; D003404:Creatinine