Comprehensive re‐evaluation of historical von Willebrand disease diagnosis in association with whole blood platelet aggregation and function

Abstract

von Willebrand disease is associated with impaired VWF-dependent whole blood platelet functions that match traditional VWF measurements. We detected normal VWF in 25% of historically diagnosed patients, mainly type 1 patients, implying that there is a need to systematically re-evaluate historical VWD diagnoses.

Whole blood ristocetin‐induced platelet impedance aggregometry does not reflect clinical severity in patients with type 1 von Willebrand disease

“…The WB-RIPA in patients with a BS ≥4 (an abnormal bleeding tendency 20 ) was highly variable, however, and the overall correlation between WB-RIPA and BS in individual patients was low. These results tended to contradict those of Nummi et al14 that had previously demonstrated a correlation between WB-RIPA and BS in type 1 VWD. It may be that the smaller number of patients (n = 7) relative to ours (n = 55) influenced the findings.…”

“…It may be that the smaller number of patients (n = 7) relative to ours (n = 55) influenced the findings. In addition, Nummi et al reported that using a ristocetin concentration at 0.8 mg/mL did not completely identify all type 1 and type 2 VWD patients, and that a ristocetin concentration at 0.6 mg/mL was more sensitive (100%) to the classification of type 1 individuals. Our WB‐RIPA assay used a ristocetin concentration at 1.2 mg/mL contained in the commercially available reagents commonly utilized for conventional RIPA with platelet‐rich plasma.…”

“…10 The technique has been used to determine the effects of antiplatelet drugs, [11][12][13] and some clinical studies have demonstrated that WB-RIPA could be a useful tool to discriminate patients with VWD from healthy controls. 10,14 Schmidt et al 15 reported, however, that the results of WB-RIPA in some patients with type 1 VWD overlapped with those in normal controls, and the reliability of the method to provide an index of clinical severity in type 1 VWD remained to be confirmed. The aims of this study were to investigate (a) whether WB-RIPA could distinguish the VWD type 1 patients from healthy controls and (b) whether WB-RIPA correlated with clinical severity of VWD type 1.…”

“…An alternative method, whole blood ristocetin‐induced platelet aggregation (WB‐RIPA) using Multiplate® platelet impedance technique (Multiple Platelet Function Analyzer; Dynabyte Medical, Munich, Germany), has been proposed, therefore, as an easy‐to‐use test for assessing platelet function in small volumes of whole blood . The technique has been used to determine the effects of antiplatelet drugs, and some clinical studies have demonstrated that WB‐RIPA could be a useful tool to discriminate patients with VWD from healthy controls . Schmidt et al reported, however, that the results of WB‐RIPA in some patients with type 1 VWD overlapped with those in normal controls, and the reliability of the method to provide an index of clinical severity in type 1 VWD remained to be confirmed.…”

Inherited Bleeding Disorders—Experience of a Not-for-Profit Organization in Pakistan

“…To differentiate type 1 from type 2 vWD, vWF:RCoF to vWF:Ag ratio of <0.7 was used. 7 Undetectable vWF:Ag and RCoF with very low FVIII level (1-9 IU/dL) led to the diagnosis of type 3 vWD. 7 Multimer analysis, von Willebrand collagen binding activity, and ristocetin-induced platelet aggregation were not performed due to the nonavailability and cost constraints.…”