Accumulative Effect of DDAVP and Heparin in Increasing Plasma Factor VIII Levels 1

. DDAVP ( l ‐desaminocysteine‐(8‐ D ‐arginine)‐vasopressin) produces a marked increase in plasma factor VIII procoagulant (F VIII:C) levels. Previously, we have reported that blood collected into heparin rather than into CPD anticoagulant results in higher starting levels of plasma F VIII:C activity. We therefore wished to determine whether the effects of these two agents were accumulative and whether they would result in any difference in the relative molecular distribution of F VIII:C. Blood was collected into CPD or heparin immediately before and 15 min after an intravenous dose of 0.2 μg/kg body weight of DDAVP. Pre‐stimulation factor VIII levels were approximately 36% higher in heparinized plasma than in CPD plasma. Following DDAVP stimulation, the final factor VIII activity was increased 3.9‐fold when either of the anticoagulants was used, with the heparin sample maintaining a 37% increase over the CPD sample. Column chromatography on Sepharose CL‐6B of pre‐ and post‐DDAVP plasma samples collected into either heparin or CPD indicated that there was no change in the relative distribution of the high and low molecular weight forms of F VIII:C. The heparinized sample showed the typical distribution of approximately 60% F VIII:C at void volume (V o ) and 40% at 2.3 V o , suggesting that DDAVP‐stimulated increases of plasma F VIII:C are equally distributed between the carrier and non‐carrier associated F VIII:C activities.