Global Thrombosis Test: Occlusion by Coagulation or SIPA?

Area of Science:

• Hematology
• Biomedical Engineering
• Medical Devices

Background:

• The Global Thrombosis Test (GTT) is a point-of-care device designed to assess thrombotic and thrombolytic states.
• The mechanism of clot formation within the GTT, specifically whether it's dominated by coagulation-driven red clots or shear stress-induced white clots, requires clarification.

Purpose of the Study:

• To investigate the histological nature of thrombus formed in the GTT.
• To evaluate the device's efficacy, usability, and limitations in clot formation.
• To determine if GTT occlusion is primarily driven by coagulation or high shear stress.

Main Methods:

• Histological analysis of thrombus formed in the GTT.
• Assessment of occlusion time (OT) under varying conditions, including the use of anticoagulants (heparin, citrate) and tissue plasminogen activator (tPA).
• Modification of the GTT by using a collagen-coated surface and eliminating the low shear zone to induce different clot types.

Main Results:

• The GTT consistently formed fibrin-rich clots containing trapped red blood cells.
• Occlusion times were significantly influenced by common anticoagulants and tPA, supporting a coagulation-driven mechanism.
• Altering the GTT surface to collagen and removing the low shear zone resulted in rapid occlusion, characteristic of platelet-rich thrombi resistant to anticoagulation and tPA.

Conclusions:

• The Global Thrombosis Test primarily measures clot formation driven by coagulation, resulting in fibrin-rich red clots.
• The GTT's occlusion mechanism differs from the high shear-induced platelet aggregation typically seen in arterial thrombosis.
• Findings clarify the GTT's utility in assessing coagulation-dependent thrombotic events.