Application of Taylor vortices in hemocompatibility investigations.
BACKGROUND
Artificial organs, implants and extracorporeal circulation affect the physiological flow characteristics of blood as a liquid organ. These artificial systems consist of a wide variety of biomaterials with different geometries and, therefore, with their own flow properties. Secondary flow also occurs in extra--as well as in intracorporeal circulation.


METHODS
In order to investigate the influence of vortical flow conditions a modified Taylor-Couette system was introduced. It consisted of two coaxial cylinders whose surfaces were the target of investigation. The annular gap was filled with donor blood shear and secondary flows were produced by rotating the inner cylinder. Platelet activation and protein adsorption were investigated as markers for thrombogenicity.


RESULTS
At shear rates high enough to establish stable Taylor vortices (G > or = 550 s(-1)) significant differences between vortical Taylor flow and steady laminar flow were detected. At shear rates of G > or = 550 s(-1) laminar flow caused a significantly higher platelet drop and PF4 release when compared to Taylor vortex flow. Also protein adsorption per square unit was significantly higher for laminar flow.


CONCLUSIONS
Based on the present data we conclude that vortical flow patterns lead to an accumulation of platelets and plasma proteins in the vortex center and therefore to a decreased probability of contact between platelets and material surfaces. It can be concluded that a preactivation of the platelets circulating in extracorporeal circuits can be manifested downstream in other geometrical configurations and flow conditions.
Körfer
S
S
Institute for Physiology, and Interdisciplinary Center for Clinical Research (IZKF) BIOMAT, RWTH Aachen, Germany. SKoerfer@Ukaachen.de
Klaus
S
S
Mottaghy
K
K
D000327:Adsorption / Q000187:drug effects; D001672:Biocompatible Materials / Q000493:pharmacokinetics / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects* / Q000502:physiology*; D001787:Blood Group Incompatibility / Q000175:diagnosis* / Q000503:physiopathology*; D001798:Blood Proteins / Q000187:drug effects* / Q000502:physiology*; D018056:Hemorheology; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D015539:Platelet Activation / Q000187:drug effects* / Q000502:physiology*; D011137:Polystyrenes / Q000493:pharmacokinetics / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects* / Q000502:physiology*; D033081:Shear Strength
D001672:Biocompatible Materials; D001798:Blood Proteins; D011137:Polystyrenes