Tissue factor-induced Thrombin Generation in the Fasting and Postprandial State among Elderly Survivors of Myocardial Infarction

Introduction: Tissue factor (TF)-induced thrombin generation (TG) ex vivo has been suggested to be an important method to assess thrombotic risk. No studies have investigated the impact of postprandial lipemia on TF-induced TG. Since myocardial infarction (MI) is associated with elevated postprandial levels of triglycerides, we hypothesized a differential impact of postprandial lipemia on coagulation activation in MI-patients and healthy controls. Material and Methods: Elderly survivors of acute MI (n=44) and healthy age-and sex matched controls (n=43) underwent a fat tolerance test (1 gram per kg body weight) to assess coagulation activation during postprandial lipemia. Results: The incremental area under the curve (AUCi) for serum triglycerides was higher in MI-patients than in healthy age-and sex matched controls (5.64 +/- 0.52 mmol/L*h and 3.94 +/- 0.39 mmol/L*h, p=0.012) during the postprandial phase. Subsequent endogenous activation of coagulation, assessed by FVIIa and thrombin generation (F1+2), was similar among groups and not related to levels of triglycerides during the postprandial phase. Healthy individuals had a gradual decline in TF-induced thrombin generation ex vivo, assessed by endogenous thrombin potential (ETP) (AUCi=-542.4 +/- 71.4 nM*min*h, p<0.001), whereas MI-patients retained their ETP (AUCi=127.4 +/- 89.0 nM*min*h, p=0.47) in plasma during the postprandial phase (p for group difference=0.005). Conclusions: MI-patients had elevated postprandial lipemia and retained their ability for TF-induced TG in plasma ex vivo in the postprandial phase, whereas the capacity gradually decreased in healthy individuals. Further studies are warranted to reveal underlying mechanism(s) and clinical implications. (C) 2009 Elsevier B.V. All rights reserved.