Platelet Damage Caused by the Centrifugal Pump: Laser‐Light Scattering Analysis of Aggregation Patterns

Abstract

Platelets are damaged by shear force during centrifugal pumping; however, the mechanism of this damage has not been fully investigated. A new laser-light scattering (LS) assay method enables quantification of real-time changes in the number of platelet aggregates of different sizes. Using this method, we assessed the kinetics of platelet damage caused by the centrifugal pump from the standpoint of platelet aggregation capacity. Conventional optical density (OD) and LS methods were used to measure platelet aggregation with a Kowa AG-10 aggregometer. Platelet aggregation in fresh human blood was evaluated in a mock circuit for 3 h under a flow rate of 5.0 L/min and a pressure head of 100 mm Hg. Test samples were obtained before pumping for control, and at 1, 2, and 3 h after the start of pumping. The test series was begun 8 times. Aggregation after stimulation by 2.0 microg/ml collagen was determined; small (9 to 25 microm), medium (25 to 50 microm), and large (50 to 70 microm) aggregates were counted by the LS method. OD measurement at hourly intervals showed significant reduction in platelet aggregation. The LS method showed that generation of small and medium aggregates was not suppressed during pumping, but that generation of large aggregates was significantly reduced at 2 and 3 h of pumping. Platelet aggregation is significantly suppressed during centrifugal pumping, and the resulting platelet dysfunction is due mainly to inhibited development of small aggregates into larger aggregates.

In Vivo Assessment of a New Method of Pulsatile Perfusion Based on a Centrifugal Pump

“…The platelet count allows an assessment to be made of blood damage (11). In fact, it is known that platelets can be damaged by shear stress in centrifugal pumps (12). Our finding on platelet count suggests that even though the flow in the new pump has a centrifugal component, the addition of the pulsatile component does not impair performance.…”

Computational evaluation of the thrombogenic potential of a hollow-fiber oxygenator with integrated heat exchanger during extracorporeal circulation

“…To the best of our knowledge, despite the abundance of studies that quantitatively assessed the effect of platelet activation (i.e., thrombus formation) in ECC components (Mellgren et al 1996;Tanaka et al 2001), there are no studies that quantitatively assessed the mechanical factors initiating platelet activation in ECC membrane oxygenators. Gartner et al (2000) demonstrated that low velocity regions qualitatively matched regions with a high incidence of thrombotic deposition.…”

“…Prior studies on BRDs for ECC focused on the experimental quantification of the effects of platelet activation, by measuring the dimension of platelet aggregates in centrifugal pumps (Tanaka et al 2001), computing the progression of thrombus growth in hemodialyzers and oxygenators (Goodman et al 2005) and comparing the formation of platelet microaggregates in centrifugal and roller pumps (Linneweber et al 2002). However, at present, there is a lack of mechanistic insight into the factors that determine platelet activation in these devices.…”

MECC Equipment

“…Shear stress and zones of stagnation and recirculation are associated with suboptimal fl ow which result in activation of red blood cells, white blood cells and platelets [8][9][10] . The damage is most prominent in a low-fl ow highresistance setting.…”