Platelet consumption in chronically induced plasma platelet factor 4-like activity reflecting rate of intravascular coagulation in dogs

Chronic intravascular coagulation was produced in eight dogs by continuous intravenous infusion of dog brain thromboplastin for 3 days to 18 days. About the third day of infusion there was a decrease in platelet count to 32% of the original value and an increase in plasma platelet factor 4-like (PF4-like) activity to 65% of the entire releasable PF4 of circulating platelets. These platelets released about twice the normal amount of PF4-like activity when aggregated in vitro with ADP. Turnover (⁵¹Cr-labeled) was 2 times faster than normal. The level of plasma PF4-like activity seems to reflect the rate of platelet consumption in intravascular coagulation and provides information about platelet kinetics.