EVAHEART: an implantable centrifugal blood pump for long-term circulatory support.
OBJECTIVE
We developed "EVAHEART": a compact centrifugal blood pump system as an implantable left ventricular assist device for long-term circulatory support. The 55 x 64 mm pump is made from pure titanium, and weighs 370 g. The entire blood-contacting surface is covered with an anti-thrombogenic coating of diamond like carbon (DLC) or 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve blood compatibility. Flows exceeding 12 L/min against 100 mmHg pressure at 2600 rpm was measured. A low-temperature mechanical seal with recirculating cooling system is used to seal the shaft. EVAHEART demonstrated an acceptably low hemolysis rate with normalized index of hemolysis of 0.005 +/- 0.002 g/100L.


METHODS
We evaluated the pump in long-term in-vivo experiments with seven calves. Via left thoracotomy, we conducted left ventricular apex-descending aorta bypass, placing the pump in the left thoracic cavity.


RESULTS
Pump flow rates was maintained at 5-9 L/min, pump power consumption remained stable at 9-10 W in all cases, plasma free Hb levels were less than 15 mg/dl, and the seal system showed good seal capability throughout the experiments. The calves were sacrificed on schedule on postoperative day 200, 222, 142, 90, 151, 155, and 133. No thrombi formed on the blood contacting surface with either the DLC or MPC coating, and no major organ thromboembolisms occurred except for a few small renal infarcts.


CONCLUSIONS
EVAHEART centrifugal blood pump demonstrated excellent performance in long-term in-vivo experiments.
Yamazaki
Kenji
K
Department of Cardiovascular Surgery, Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan.
Kihara
Shinichiro
S
Akimoto
Takehide
T
Tagusari
Osamu
O
Kawai
Akihiko
A
Umezu
Mitsuo
M
Tomioka
Jun
J
Kormos
Robert L
RL
Griffith
Bartley P
BP
Kurosawa
Hiromi
H
D000818:Animals; D002417:Cattle; D006353:Heart-Assist Devices; D011474:Prosthesis Design