Abstract Number: LPB0014
Meeting: ISTH 2021 Congress
Background: The Global Thrombosis Test (GTT) has been proposed as a point of care device to quantify thrombotic and thrombolytic status. Is GTT thrombosis is dominated by coagulation or high shear-induced platelet aggregation (SIPA)?
- Demonstrate that GTT occludes predominantly by coagulation induced fibrin, blocked by heparin, and lysed by tPA.
- Create alternative conditions for faster occlusion by SIPA, resistant to tPA.
Methods: Thrombus formed in the GTT was run with fresh human blood according to the Instructions and the Occlusion Time (OT) recorded without and with heparin or tPA. Occlusive thrombi were stained with Carstairs to detect fibrin or platelets. The assay was then modified to eliminate the low shear zone and coat with fibrillar collagen.
Results: The GTT formed thrombi in the gaps between the beads that were fibrin-rich. The OT was long at 526 ±188s, and was strongly lengthened by heparin (847±106s,p<0.0001,n=12). tPA caused lysis (865s) in half the time of control (1660s,p<0.005). In contrast, the modified assay created thrombi that were rich in platelets. Occlusion time was shortened to 217 ± 71s (p=0.0005) while heparin caused a slight increase to 244s. Both the control and tPA lysis times were prolonged beyond the control lysis time for the original GTT. The rapid attachment of platelets to fibrillar collagen and relative resistance to heparin and tPA created a SIPA-like thrombosis. Unfortunately, both the original GTT and modified assay exhibited large variability.
Conclusions: GTT occludes primarily from a clot that is rich in fibrin in the low-shear zone, in a longer time-scale of the coagulation cascade, and is affected strongly by heparin; despite the existence of a high shear gap in the system. The tubular test section could be modified to induce faster occlusion with a SIPA platelet-rich thrombus, that was relatively resistant to tPA.
To cite this abstract in AMA style:Clavería V, Yang P, Griffin M, Ku D. Global Thrombosis Test: Occlusion by Coagulation or SIPA? [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/global-thrombosis-test-occlusion-by-coagulation-or-sipa/. Accessed January 26, 2022.
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