Platelet factor XIIIa release during platelet aggregation and plasma clot strength measured by thrombelastography in patients with coronary artery disease treated with clopidogrel

Rolf P. Kreutz, Janelle Owens, Deshun Lu, Perry Nystrom, Yan Jin, Yvonne Kreutz, Zeruesenay Desta, David A. Flockhart

Research output: Contribution to journalArticle

5 Scopus citations


It has been estimated that up to half of circulating factor XIIIa (FXIIIa) is stored in platelets. The release of FXIIIa from platelets upon stimulation with adenosine diphosphate (ADP) in patients with coronary artery disease treated with dual antiplatelet therapy has not been previously examined. Samples from 96 patients with established coronary artery disease treated with aspirin and clopidogrel were examined. Platelet aggregation was performed by light transmittance aggregometry in platelet-rich plasma (PRP), with platelet-poor plasma (PPP) as reference, and ADP 5μM as agonist. Kaolin-activated thrombelastography (TEG) was performed in citrate PPP. PRP after aggregation was centrifuged and plasma supernatant (PSN) collected. FXIIIa was measured in PPP and PSN. Platelet aggregation after stimulation with ADP 5μM resulted in 24% additional FXIIIa release in PSN as compared to PPP (99.3±27 vs. 80.3±24%, p<0.0001). FXIIIa concentration in PSN correlated with maximal plasma clot strength (TEG-G) (r=0.48, p<0.0001), but not in PPP (r=0.15, p=0.14). Increasing quartiles of platelet-derived FXIIIa were associated with incrementally higher TEG-G (p=0.012). FXIIIa release was similar between clopidogrel responders and non-responders (p=0.18). In summary, platelets treated with aspirin and clopidogrel release a significant amount of FXIIIa upon aggregation by ADP. Platelet-derived FXIIIa may contribute to differences in plasma TEG-G, and thus, in part, provide a mechanistic explanation for high clot strength observed as a consequence of platelet activation. Variability in clopidogrel response does not significantly influence FXIIIa release from platelets.

Original languageEnglish (US)
Pages (from-to)358-363
Number of pages6
Issue number4
StatePublished - Jun 1 2015



  • Clopidogrel
  • Coagulation
  • Factor XIII
  • Platelet aggregation
  • Thrombelastography

ASJC Scopus subject areas

  • Hematology

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