Prothrombin complex concentrates: potentially thrombogenic materials and
clues to the mechanism of thrombosis in vivo
GC White , HR Roberts, HS Kingdon and RL Lundblad
Factors affecting the coagulant activity of two different prothrombin
complex concentrates have been investigated using a sensitive in vitro
assay developed in this laboratory. One concentrate contained substantial
amounts of potentially thrombogenic material, while the other, which was
deliberately fortified with antithrombin III and heparin during production,
was judged to be relatively nonthrombogenic. The coagulant activity of the
thrombogenic concentrate has been partially identified and was due largely
to the presence of coagulation factos IXa and Xa. Neither concentrate
contained detectable thrombin. However, after incubation with calcium or
various polyamines, large amounts of additional coagulant material,
including thrombin, appeared. Heparin and antithrombin III not only
neutralized the thrombogenic materials present in the thrombogenic
concentrate, but also inhibited the de novo generation of coagulant enzymes
during incubation with calcium. The implication of these studies on the
preparation of prothrombin complex concentrates and on host susceptibility
to thrombosis during the clinical use of these concentrates is discussed.
Volume 49,
Issue 2,
pp. 159-170,
02/01/1977
Copyright © 1977 by The American Society of Hematology
