Improvement in antithrombogenicity in a centrifugal pump with self wash-out structure for long-term use.
Antithrombogenicity in the initial (NCVC-1) centrifugal pump (CP) developed at our institute is provided by a central balancing hole in an impeller that promotes self wash-out blood flow (Sf) around the impeller. The current CP (NCVC-2) was ameliorated to obtain better antithrombogenicity, where the balancing hole diameter was widened to improve Sf velocity (Vsf), and the edge of a thrust bearing (TB) was rounded to minimize flow separation. Effects of the modifications were assessed in in vitro and in vivo studies. The Vsf of the NCVC-1 and the NCVC-2 evaluated by Doppler velocimeter were 12.8 and 22.1 cm/sec, respectively. Flow around the TB visualized by a light cutting method confirmed less flow stagnation in the NCVC-2. In vivo antithrombogenicity of the CPs was investigated in three goats. A pulsatile VAD (P-VAD) was installed paracorporeally between the left atrium and the aorta. After 3 weeks, the P-VAD was exchanged for the NCVC-2 and the NCVC-1 in sequence. Each CP was driven for 1 week and disassembled. No anticoagulation was used, except for heparin injection at pump exchange. Thrombus at the TB was found in the two NCVC-1s, and two little thrombi were on the impeller of another NCVC-1, whereas a thrombus smaller than 1 mm3 at the TB was noted in one NCVC-2. These results indicate that the NCVC-2 has better antithrombogenicity and Sf around the impeller and the TB.
Wakisaka
Y
Y
Department of Artificial Organs, National Cardiovascular Center Research Institute, Osaka, Japan.
Taenaka
Y
Y
Tatsumi
E
E
Araki
K
K
Masuzawa
T
T
Nakatani
T
T
Baba
Y
Y
Anai
H
H
Eya
K
K
Toda
K
K
D000818:Animals; D001698:Biomedical Engineering; D001783:Blood Flow Velocity; D002498:Centrifugation / Q000009:adverse effects / Q000295:instrumentation; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006041:Goats; D006353:Heart-Assist Devices / Q000009:adverse effects; D006461:Hemolysis; D066298:In Vitro Techniques; D017078:Laser-Doppler Flowmetry; D013927:Thrombosis / Q000517:prevention & control*; D013997:Time Factors