Laboratory assays for von Willebrand Factor: relative contribution to the diagnosis of von Willebrand’s disease

Favaloro, Emmanuel J.; Koutts, Jerry

doi:10.1080/00313029700169365

Cited by 59 publications

(109 citation statements)

References 15 publications

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“…21 The vWF:CB/ vWF:AG ratio has been shown to perform at least equal to the measurement of ristocetin cofactor activity as long as suitable collagens are used. 22 The vWF:CB/vWF:AG ratio used here was the preferred method because of a higher level of precision. However, a limitation of this approach is that other abnormalities in addition to the presence or absence of large multimers were not detected in our analysis.…”

Section: Discussionmentioning

confidence: 99%

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Meyer

Malehsa²,

Bara³

et al. 2010

Circ: Heart Failure

260

149

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Background-Rotary blood pumps used as left ventricular assist devices (LVADs) allow for long-term support and may become suitable alternatives to heart transplantation. Effects of this technology on the coagulation system are not completely understood, leading to controversial anticoagulation protocols. Thus, we investigated the primary hemostasis in patients with chronic LVAD therapy. Methods and Results-Twenty-six outpatients received axial flow LVAD (HeartMate II; Thoratec) for a median support time of 4.5 months. In a cross-sectional protocol, platelet aggregation in response to ADP and epinephrine, von Willebrand antigen (vWF:AG), and collagen-binding capacity (vWF:CB) were obtained. Von Willebrand factor (vWF) multimer analyses were performed, and patients were screened for bleeding events. This analysis was repeated after removal of the device for transplantation or recovery (nϭ12) and after a median of 15.5 months in ongoing patients (nϭ11). In all patients on devices, severe impairment of platelet aggregation as well as a loss of large vWF multimers were found. In 10 patients, a decreased vWF:CB/vWF:AG ratio was observed. Bleeding episodes occurred with an incidence of 0.17 per patient-year. After removal of the device, normal patterns of platelet aggregation, multimer analysis, and vWF:CB/vWF:AG ratio were recorded. In the second analysis of ongoing patients, impairment of platelet aggregation and loss of large vWF multimers were verified. Conclusions-A diagnosis of von Willebrand syndrome type 2 was established in all patients after LVAD implantation, and bleeding events confirmed this finding. Reversibility of this condition was found after removal of the device. (Circ Heart Fail. 2010;3:675-681.)

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Section: Discussionmentioning

confidence: 99%

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Meyer

Malehsa²,

Bara³

et al. 2010

Circ: Heart Failure

260

149

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“…A newer method for assessing the activity of VWF is the VWF collagen binding assay. Unfortunately, both measures of VWF function are subject to considerable technical problems, with high relative interassay variability and high interlaboratory variability (8). Adding to the difficulty of making a diagnosis, VWF levels can increase in response to a variety of stressors and in certain chronic illnesses.…”

Section: Laboratory Diagnosismentioning

confidence: 99%

The diagnosis and treatment of von Willebrand disease in children

Klaassen

Halton

2002

Paediatrics &Amp; Child Health

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“…VWD is a heterogeneous disorder, and patients are typed according to pathophysiology with classification protocols involving both clinical observations and laboratory analysis [1][2][3][4][5][6]. In order to appropriately diagnose a patient with VWD, a panel of laboratory assays is typically required, not necessarily restricted to an assessment of VWF [7]. This is due to both the presence of VWD heterogeneity and because of the diagnostic limitations of any given laboratory assay.…”

Section: Introductionmentioning

confidence: 99%

Use of a novel platelet function analyzer (PFA-100?) with high sensitivity to disturbances in von willebrand factor to screen for von willebrand's disease and other disorders

1999

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The PFA-100™ is a new platelet function analyzer which uses whole blood and high shear stress blood flow to simulate primary hemostasis and assess platelet function. A small volume of blood is introduced into a disposable cartridge, and forced through a capillary tube. Platelet adhesion and aggregation is then initiated following exposure to either collagen/ADP ] were found to be inhibitory (i.e., prolonged the CT). Data using polyclonal antibodies (against platelets, VWF, fibrinogen and fibronectin) is more complex but largely confirms the sensitivity of the system to VWF. On the basis of these results, we conclude that the PFA-100™ is highly sensitive to disturbances in VWF and to the presence of VWD and may thus provide a valuable screening test for VWD in certain specific circumstances (i.e., acute need conditions or remote testing sites; normal CT result generally effective as negative predictor, i.e. not severe VWD). However, since abnormal CT values were obtained in clinical situations other than evident VWD, the PFA-100™ cannot be used as a specific diagnostic tool to establish the presence of VWD. Thus, any abnormal PFA-100™ CT result should be thoroughly evaluated by followup specific testing to establish the true clinical disorder affecting the individual under investigation, inclusive of appropriate VWF assays if VWD is clinically suspected. Am. J. Hematol. 62:165-174, 1999.

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Laboratory assays for von Willebrand Factor: relative contribution to the diagnosis of von Willebrand’s disease

Cited by 59 publications

References 15 publications

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

The diagnosis and treatment of von Willebrand disease in children

Use of a novel platelet function analyzer (PFA-100?) with high sensitivity to disturbances in von willebrand factor to screen for von willebrand's disease and other disorders

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