State and diagnostic value of plasma tissue factor in early-hospitalised patients with chest pain.

To study the state and diagnostic value of plasma tissue factor (TF) in patients with acute coronary syndromes (ACS), we quantitatively compared plasma TF antigen and TF activity in 90 early-hospitalised patients with chest pain. Using high-affinity antibodies, a sensitive assay for TF antigen was developed with a detection limit of 40 fmol/l. One of the antibodies was used to capture TF from plasma and, after elution and dialysis-free reconstitution in phospholipid-glucoside micelles, absolute amounts of TF activity could be measured with a detection limit of 80 fmol/l. All TF in plasma was found to be exposed, and a value of 2.5(1.1-14.8) pmol/l (median with range) was found for TF antigen. Most of this TF antigen (70-80%) circulated in a (potentially) functional state. Left in its in vivo state, however, TF captured from plasma was totally inactive, probably because of the lack of a procoagulant matrix. Compared with controls with non-cardiac chest pain, TF activity was unchanged and TF antigen about 25% elevated in ACS patients. Combined with the markers prothrombin fragment F1+2 and fatty acid-binding protein, TF did not improve the early diagnosis of ACS.