Heightened Tissue Factor Associated With Tissue Factor Pathway Inhibitor and Prognosis in Patients With Unstable Angina

BACKGROUND: This study was designed to evaluate the plasma levels of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in patients with unstable angina and investigate whether there is a relationship between these levels and unfavorable outcome. METHODS AND RESULTS: The plasma TF and free TFPI antigen levels were determined in plasma samples taken from 51 patients with unstable angina, 56 with stable exertional angina, and 55 with chest pain syndrome. The plasma TF and free TFPI antigen levels were higher in the unstable angina group than in the stable exertional angina and chest pain syndrome group. There was a good correlation between TF and TFPI. We established borderline as maximum level in the patients with chest pain syndrome. Seven patients (of the 22 in the high TF group) required revascularization to control their unstable angina during in-hospital stay. On the other hand, only 1 of the 29 patients in the low TF group required myocardial revascularization. Four patients of the 14 patients in the high free TFPI group required myocardial revascularization during in-hospital stay, and 4 of the 37 patients in the low free TFPI group required myocardial revascularization. We compared the TF and free TFPI levels between the cardiac event (+) group and cardiac event (-) group. TF levels were significantly higher in the cardiac event (+) group than in the cardiac event (-) group. CONCLUSIONS: We have demonstrated that not only the plasma TF levels but also the plasma-free TFPI levels are elevated in patients with unstable angina. Patients with unstable angina and heightened TF and free TFPI are at increased risk for unfavorable outcomes. The heightened TF level was a more important predictor in patients with unstable angina.