Studies in Intravascular Coagulation. Iii. The Pathogenesis of Serum-Induced Venous Thrombosis 12

The mechanisms involved in the initiation, prop- agation, and dissemination of intravascular clots remain obscure. The identification of each new clotting factor has raised the possibility that ab- normalities in these factors might be found among patients with thromboembolism. Data have yet to be presented, however, demonstrating a causal relationship between intravascular thrombosis and an alteration in any of these clotting factors. Our efforts to uncover such a relationship proceeded from two observations. One was the impressive evidence that stasis plays an important role in the development of intravascular clotting. The other was the significant fact first established by Alex- ander, deVries, and Goldstein (1) and later con- firmed by Owren (2) and Koller, Loeliger, and Duckert (3) that there is normally present in hu- man serum a stable factor which accelerates pro- thrombin conversion. This factor has been vari- ously called SPCA, Converting and factor VII.