The Xylum Clot Signature Analyzer: a dynamic flow system that simulates vascular injury.
The Xylum Clot Signature Analyzer (CSA) is an automated, user-friendly, benchtop analyzer that assesses platelet function and coagulation in non-anticoagulated whole blood under physiological flow and temperature conditions. From blood drawn in a single venipuncture, the CSA measures: a) the time for platelets to occlude holes "punched" in a blood conduit (platelet hemostasis time or PHT); b) collagen-induced thrombus formation (CITF) as blood flows in a channel containing a collagen fiber; and c) clotting time (CT). Micrographs show platelet-rich thrombi in the punched holes and on the collagen surface after a run. PHT and CITF increased at lower shear rate, suggesting that shear activation of platelets is involved in hole closure and in collagen-induced thrombus formation. In blood mixed with anti-von Willebrand's factor (vWF) antibodies, anti-GPIb antibodies, aurin tricarboxylic acid (ATA), or anti-GPIIb-IIIa, PHT and CITF were prolonged, further supporting the reflection of platelet function by those parameters. At low shear rate (<1000 sec(-1)), native blood and blood treated with anti-vWF did not have significantly different PHTs or CITFs. At high shear rate (>6000 sec(-1)), the PHT and CITF of the anti-vWF-treated sample were significantly greater than those of the untreated sample. This supports the inhibition of shear-induced activation of platelets by anti-vWF in the CSA. Heparin-treated blood showed significantly longer CT, indicating that coagulation of blood under flow is inhibited by heparin. The CSA thus assess multiple aspects of hemostasis under near-physiological conditions.
Li
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Xylum Corporation, Scarsdale, New York 10583, USA. Conan_Li@Xylum.ccmail.compuserve.com
Hoffmann
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Hsieh
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Malik
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Watson
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D001681:Biological Assay / Q000295:instrumentation*; D006487:Hemostasis; D006801:Humans; D013314:Stress, Mechanical; D014652:Vascular Diseases