Abstract Number: PB0151
Meeting: ISTH 2020 Congress
Background: A unique non-human primate (NHP) ex vivo shunt model has long been used to robustly assess material thrombogenicity and anticoagulant efficacy by measuring platelet deposition from whole, flowing, uncitrated blood in real time. A retrospective analysis of control trials was undertaken to identify biological predictors of thrombus dynamics.
Aims: Determine biological parameters predictive of platelet deposition dynamics in ex vivo NHP studies.
Methods: Expanded polytetrafluoroethylene (ePTFE) tubes (4 mm ID) were placed in the blood flow path of a chronically implanted femoral artery to vein loop in male juvenile Papio anubis baboons. Autologous 111In-labeled platelets and homologous 125I-labeled fibrinogen were infused into NHPs prior to experiments. Blood flow was controlled at 100 ml/min, and the platelet deposition signal from 111In was measured for 1 hr by a gamma camera once every one, three or five minutes. For the current analysis, data from 20 experiments with ePTFE controls over seven animals is used. Study files are manually segmented using FIJI (SciJava) and exported as 4D matrices to R (R foundation for statistical computing) for analysis.
As illustrated in Figure 1A, the final twenty minutes of platelet deposition grouped by animal reveal a trend consistent within animals. Thrombus tends to either continue growing at a linear rate, level off, or decrease in size. The rate of platelet deposition in these final twenty minutes inversely correlates with the average activated partial thromboplastin time (aPTT) of each animal, as shown in Figure 1B.
Conclusions: The platelet deposition data from ePTFE shunts demonstrate similarity among experiments from the same animals and is inversely related to aPTT, suggesting that aPTT may be a predictor of platelet deposition dynamics on biomaterials. Further analysis of an expanded dataset using linear mixed effects modeling could identify more predictors of thrombus growth dynamics.
To cite this abstract in AMA style:Hagen MW, Lakshmanan HHS, Fallon ME, McCarty OJT, Hinds MT. Identification of Thrombosis Predictors in an ex vivo Shunt Model through Retrospective Analysis [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/identification-of-thrombosis-predictors-in-an-ex-vivo-shunt-model-through-retrospective-analysis/. Accessed May 6, 2021.
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