Biomaterials for Rotary Blood Pumps

Rotary blood pumps are used for cardiac assist and cardiopulmonary support since mechanical blood damage is less than with conventional roller pumps. The high shear rate in the rotary pump and the reduced anti‐coagulation of the patient during prolonged pumping enforces high demands on the biocompatibility of the materials in the pump in order to prevent thrombus formation. Materials with a very hydrophobic character appear to adsorb much thrombin and induce a conformational change of fibrinogen, resulting in a surface with a high affinity for platelet interaction. Furthermore, heigh shear forces of 120 dyne‐s‐cm 2 in rotary pumps induce platelet release and platelet aggregation. Thus, hydrophobic materials and high shear rates should be prevented to avoid thrombus formation in rotary blood pumps.