Consistency of responses to repeated DDAVP infusions in patients with von Willebrand's disease and hemophilia A.

The consistency in time of responses to separate desmopressin (DDAVP) infusions in patients with von Willebrand's disease (vWD) and mild or moderate hemophilia A has been the subject of limited investigation. We report here the results of a clinical study undertaken to test the consistency of responses to repeated DDAVP administrations in 22 patients with vWD and 10 with mild or moderate hemophilia A (time interval between first and last infusion ranging from 1 to 77 months; median, 13 months). In patients with vWD, 80% of cases showed a departure of less than 20% from the average VIII:C peak level calculated after the two infusions. A similarly consistent pattern was observed for bleeding times recorded 30 minutes after each infusion. In patients with hemophilia A, some infused on more than two instances, the departure from the average VIII:C peak level was less than 20% in nearly 70% of cases. A good within-family consistency was also demonstrated by analyzing data obtained from seven kindreds with vWD and two with hemophilia A. In conclusion, our study suggests that the pattern of responsiveness observed after a DDAVP test-infusion can be reliably used to decide the future clinical management of the individual patient and that a similar pattern of response is usually observed within the same kindred.