The PFA-100 closure time normalized in all type 1 von Willebrand disease patients after desmopressin infusion, providing a rapid tool to discriminate between good and non-responders.
Observational (n=41)
Does the Platelet Function Analyzer PFA-100 accurately evaluate the response to desmopressin or VWF concentrates in patients with von Willebrand disease?
The PFA-100 closure time is a simple and rapid tool to discriminate between good and non-responders to desmopressin in patients with von Willebrand disease.
We have evaluated the position of the Platelet Function Analyzer PFA-100TM in the management of 41 patients with von Willebrand disease (VWD) receiving either desmopressin (23 patients with type 1, five with type 2M, three with type 2A and three with type 2B) or von Willebrand factor (VWF) concentrates (four patients with type 3, two with type 2M 'type B', two with type 2A and one type 1 'platelet low'). In all patients the following were studied before and 30 min after infusion of desmopressin and/or VWF concentrates: VWF ristocetin cofactor activity (VWFRCo), bleeding time (BT) and closure time with the PFA-100 using ADP (CT-ADP) as well as epinephrine (CT-Epi) cartridges. After the infusion of desmopressin, the CT was modified in the same way as the VWFRCo levels, being always normalized in patients with type 1 and not constantly corrected in those with type 2. Thus, our results indicated that the measurement of the CT enabled a quick and accurate evaluation of the response to desmopressin which, in fact, measured the releasable VWF cellular compartment containing the highly multimerized forms of VWF. For patients with type 2 or 3 VWD who were non-responsive to desmopressin, VWF concentrates corrected the VWFRCo defect but not the CT as none of these patients had a normal platelet VWF content and the VWF concentrates did not contain the ultralarge VWF multimers. In conclusion, the very high shear conditions in the PFA-100 make it very sensitive to the contribution of platelet VWF and to the ultralarge VWF multimers, indicating that the evaluation of the CT is a very simple and rapid tool to discriminate between good and non-responders to desmopressin.
Fressinaud et al. (Wed,) conducted a observational in von Willebrand disease (n=41). Desmopressin or von Willebrand factor concentrates vs. Baseline (before infusion) was evaluated on Closure time with the PFA-100 using ADP and epinephrine cartridges, VWF ristocetin cofactor activity, and bleeding time. The PFA-100 closure time normalized in all type 1 von Willebrand disease patients after desmopressin infusion, providing a rapid tool to discriminate between good and non-responders.