Exercise Versus DDAVP in Patients With Mild Hemophilia A

Persons with mild hemophilia A (MHA) (defined as having a FVIII level of \>5% to ≈50%) bleed infrequently but can in the setting of trauma which can often is in the context of participating in sports/exercise. FVIII levels temporarily rise with stress, exercise and with DDAVP (1-desamino-8-Darginine vasopressin, desmopressin). In the case of DDAVP, the Hospital for Sick Children (SickKids) Hemophilia Team and others have shown that FVIII and VWF levels rise by 2-4 fold with DDAVP. Consequently many persons with MHA in an attempt to reduce their risk of bleeding take intranasal (IN) DDAVP prior to sports activities/exercise. IN DDAVP is reasonably expensive ($300/bottle of Octistim® in Canada and $700/bottle of Stimate® in USA), requires fluid restriction, and may be associated with nausea, vomiting, seizures and tachyphylaxis. Recently, our group completed a pilot/feasibility study to evaluate the impact of a prescribed, moderate intensity aerobic exercise regimen on hemostatic indices in 30 children with hemophilia A \[HA\] or B \[HB\] (all severities) and documented a significant improvement in multiple coagulation parameters (platelet count, FVIII:C and von Willebrand factor \[VWF\]) with exercise. This improvement was particularly pronounced in 13 post-adolescent males with mild-moderate HA. In this sub-cohort, the investigators noted a mean 2.3 fold increase in FVIII:C immediately after exercise, which remained significantly elevated at 1.9 fold,1 hour after completion of exercise These changes in hemostatic variables associated with aerobic exercise may be protective against bleeding, and may negate the need to administer IN DDAVP immediately prior to sports participation. Although both exercise and DDAVP can raise FVIII/VWF levels, it is not clear whether the pathophysiological mechanism in which they do this is the same. Consequently it is not known if DDAVP and exercise would augment each other's effects in raising FVIII:C and VWF levels or if one would one negate the effect of the other. Herein, the investigators propose a prospective, interventional study of exercise vs IN DDAVP in 40-50 post adolescent (13-21 yr) males with MHA to compare their impact on hemostasis and also to investigate the impact of sequentially administering these interventions on hemostatic indices.