Secondary Logo

Journal Logo

ASAIO CARDIAC ABSTRACT

FLOW CHARACTERISTICS AND WALL SHEAR AND THEIR CORRELATION WITH CLOT FORMATION IN THE 50cc PENN STATE ARTIFICIAL HEART

Hochareon, P1; Manning, K B1; Fontaine, A A1; Tarbell, J M2; Deutsch, S1

Author Information
  • Free

We have recently completed a study of the 50cc Penn State Artificial Heart in which particle image velocimetry (PIV) measurements provided a wall shear stress distribution about the centerline of the heart as a function of cycle time. Yamanaka et al. (1) implanted a similar model in 3 calves, to test for clot formation (CF). Although CF was not prevalent, they observed one long, narrow clot loosely attached to the bottom surface, off center. Flow visualization results and results from a sac opening study (2), suggest that the flow at the bottom is highly three dimensional, with low shear throughout the cycle. To explore the correlation with CF further, we extended our PIV shear study to include 3 planes (3, 6 and 9 mm) from the frontal edge of the artificial heart. Measurements were made at normal physiological operating conditions. The image magnification was gave a spatial resolution of 160 μm for wall shear. Velocity maps were constructed from ensemble averages of 200 instantaneous velocity fields. Processing details are in (2). The wandering inlet jet is the major feature of the flow during diastole. The jet's behavior is a result of the inlet valve orientation and the opening pattern of the heart sac. We observe that the region of CF is an area of persistently low shear stress. Although much work remains, this suggests that the fluid mechanics is intimately related to the CF and that by changing the flow (valve orientation), one may eliminate clotting. 1. Yamanaka et al. ASAIO J, 2003;49:222. 2. Hochareon. PhD Thesis, Penn State Univ., 2003.

Copyright © 2004 by the American Society for Artificial Internal Organs