Platelet Damage Accumulation and Recovery due to Hemodynamic Shear Stresses: An In Vitro Study

It is well established that shear stress exposure activates platelets, and it has been shown that this flow-induced activation contributes significantly to thromboembolic complications in mechanical heart valves (MHVs) [1]. In addition, the platelet activation state (PAS) assay has been demonstrated to be an efficient technique to measure procoagulant activity [2]. However, there is a lack of reliable models to predict platelet damage accumulation. Such a tool allows thrombogenicity optimization of implanted prosthetic devices. Prior to developing this tool, certain aspects of platelet behavior in response to shear stress must be elucidated. Of special importance for developing accountable damage accumulation models is the recovery potential of platelets during repeated passages through devices, when not exposed to the elevated stresses characterizing blood flow in these devices. To accomplish this, PAS measurements were conducted in a Hemodynamic Shearing Device (HSD), where platelets were exposed to prescribed waveforms with alternating periods of high and low shear stresses.