State-of-the-Art Review : Evaluation of the Clot Signature Analyzer as a Hemostasis Test in Healthy Volunteers Exposed to Low Doses of Aspirin

• Published in: Clinical and applied thrombosis/hemostasis Vol. 5; no. 2; pp. 117 - 121
• Main Authors: Igawa, Takehiro, Kornhauser, Robyn, Cilla, Donald D., O'Neal King, Jennifer, Kambayashi, Junichi
• Format: Journal Article
• Language: English
• Published: Thousand Oaks, CA SAGE Publications 01.04.1999; SAGE PUBLICATIONS, INC
• Subjects: Aspirin; Collagen; Health risk assessment; Collagen-induced thrombus formation (CITF); Platelet aggregation; Clot Signature Analyzer (CSA); Platelet hemostasis time (PHT); Key Words: Bleeding time
• ISSN: 1076-0296; 1938-2723
• DOI: 10.1177/107602969900500208

Several variables affect bleeding time that make it difficult to obtain consistent measurements. The Clot Signature Analyzer (CSA) has been developed to assess in vitro hemo stasis using well-controlled flow chambers. In this study, the equivalencies in the CSA parameters with the conventional bleeding time or platelet aggregation methods were evaluated in subjects exposed to aspirin. The CSA parameters, platelet hemostasis time (PHT) and collagen-induced thrombus forma tion (CITF), were compared to bleeding time (Surgicutt2®) and collagen-induced platelet aggregation, respectively. Fifty-three healthy volunteers were given two doses of aspirin (81 and 243 mg) in one day. Following the baseline period, the volunteers took 81 mg of aspirin and then took 243 mg 2 hours later. The changes in each value from the baseline to that at either aspirin dose (2 hours after dosing) were evaluated. Platelet hemostasis time and CITF correlated well with bleeding time and aggre gation, respectively, but PHT was not significantly increased after 81 mg of aspirin, whereas bleeding time was significantly increased. The variation in PHT was slightly higher than that of bleeding time. At 81 mg, CITF was significantly increased but aggregation was not, even though the variation was compa rable. This suggests that PHT and CITF can simulate the changes in bleeding time and aggregation, respectively, but the sensitivity of PHT for detecting the changes in bleeding time was no better than the conventional method. Also, CITF was more sensitive than aggregation in detecting platelet re sponse to collagen. In conclusion, the proposed CSA is not always suitable for detecting hemostatic abnormalities.