Recent acquisitions in acquired and congenital von Willebrand disorders

Acquired von Willebrand Syndrome in a Patient Undergoing Extracorporeal Membrane Oxygenation: A Case Report

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder caused by dysfunction of the von Willebrand factor (vWF), leading to bleeding manifestations. It usually occurs due to an underlying disorder in patients with no family or personal history of bleeding diathesis. The exact mechanism causing this syndrome is not fully understood, but it involves a complex interplay of factors. Specifically, vWF deficiency or reduced activity can occur due to antibodies, adsorption of vWF onto tumor cells, shear stress, or increased proteolysis. We describe a patient with severe, right-sided heart failure secondary to idiopathic pulmonary hypertension. The patient was admitted to the intensive care unit to be placed on a venoarterial extracorporeal membrane oxygenation (VA ECMO) machine while awaiting bilateral lung transplantation. A few hours after initiation of VA ECMO, the patient experienced epistaxis and continuous bleeding from the cannula tips. The laboratory investigations were based on the measurements of vWF antigen (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), and multimer analysis. The obtained results revealed a decreased VWF:RCo/VWF:Ag ratio (<0.7) and the loss of high-molecular-weight multimers of vWF, thus confirming the diagnosis of AvWS. This report reviews how to make the clinical diagnosis of AvWS, including a discussion of necessary laboratory results and their pitfalls, and highlights the importance of having a high index of suspicion of AvWS in the ECMO population so that laboratory values are obtained on time to allow for treatment and successful recovery.

Acquired von Willebrand syndrome: focused for hematologists

The acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder with laboratory findings similar to those of inherited von Willebrand disease. However, unlike the inherited disease, AvWS occurs in persons with no personal and family history of bleeding and is often associated with a variety of underlying diseases, most frequently lymphoproliferative, myeloproliferative and cardiovascular disorders. After the presentation of a typical case, in this narrative review we discuss the more recent data on the pathophysiology, clinical, laboratory and therapeutic aspects of this acquired bleeding syndrome. We chose to focus particularly on those aspects of greater interest for the hematologist.

Advances in managing rare acquired bleeding disorders

INTRODUCTION

Rare acquired bleeding disorders include a wide spectrum of coagulopathies characterized by spontaneous or post-trauma and post-surgery hemorrhages in patients without a previous personal or family history of bleeding.

AREAS COVERED

This review, based on a Medline/PubMed search during the last 20 years, will focus mainly on rare acquired bleeding disorders caused by autoantibodies against coagulation factors, including autoantibodies against factor VIII (acquired hemophilia A), von Willebrand factor (acquired von Willebrand syndrome) and other coagulation factors (factors V, X, XI, and XIII). The pathogenic, laboratory, and clinical features of these rare hemorrhagic conditions will be discussed, with particular attention to their management.

EXPERT OPINION

The treatment of rare acquired bleeding disorders includes the control of bleeding and the elimination of the autoantibody and of the underlying disease, when present. As the bleeding clinical phenotype is often severe, the management of affected patients is particularly challenging. Thus, while an early diagnosis of the acquired coagulopathy is essential to start the most appropriate treatment and to improve patients' outcomes, the support of specialized centers is equally important to provide a correct management of such complicated cases.

Acquired von Willebrand's disease associated with epithelial myoepithelial carcinoma of the parotid salivary gland

This is the first case report of a patient with acquired von Willebrand's disease (AvWD) secondary to epithelial myoepithelial carcinoma (EMC) of the parotid salivary gland. This patient presented to haematology following an abnormal bleeding episode with von Willebrand factor Ristocetin cofactor (VWF:RCo) <5% and VWF:Ag 13%. He was diagnosed with AvWD. At the same time he was found to have a left parotid lump which was excised following a multidisciplinary team meeting. This was histologically reported as an EMC. Following excision, unusually this patient's AvWD did not resolve. Extensive investigation looking for other causes of the AvWD did not reveal any other potential cause; therefore, due to the similar timing of onset of both pathologies it is felt that the AvWD in this case is secondary to the EMC. This case report highlights the presentation, investigation and management of AvWD and parotid lumps as well as discussing proposed pathophysiological mechanisms for AvWD.

Acquired von Willebrand disease and multiple myeloma: a case report of a breast cancer survivor

Acquired von Willebrand disease (aVWD) is rare disease and is associated with a variety of underlying diseases. We report a case of aVWD in the setting of multiple myeloma. The patient was a 63-year-old female with breast cancer in remission who was admitted for symptomatic anemia. She was diagnosed with multiple myeloma. She also had subcutaneous bleeding before admission. Laboratory studies revealed isolated prolongation of the activated partial thromboplastin time, which corrected in a mixing study. Her factor VIII activity, von Willebrand factor (VWF) Ag, and VWF activity were low. VWF multimer study confirmed the patient had aVWD. The treatment of aVWD is discussed in this article, including the treatment of underlying diseases, and acute management in emergent situations. An intriguing question in this case is whether the patient's multiple myeloma is a chemotherapy-induced hematological malignancy or a second primary malignancy.

Rituximab effectiveness in a patient with juvenile systemic lupus erythematosus complicated with acquired Von Willebrand syndrome

The acquired von Willebrand Syndrome (AvWS) is a bleeding disorder with laboratory findings similar to those of the congenital form. Its presentation is more common in adults than in children and is mainly associated with lymphoproliferative and myeloproliferative diseases and rarely with autoimmune diseases including systemic lupus erythematosus (SLE). Here, we report the case of a girl with SLE and AvWS with mucosal bleeding and low plasma levels of von Willebrand factor and factor VIII (FVIII) with failure to respond to treatment with first- and second-line therapies. The patient finally responded to rituximab. To our knowledge this is the first reported case of SLE associated with AvWS, that responded to rituximab.

Markers of coagulation activation, endothelial stimulation, and inflammation in dogs with babesiosis

BACKGROUND

Babesia infections in dogs can result in a wide range of clinical and laboratory presentations, including coagulopathy. Expression of intercellular adhesion molecule-1 (ICAM-1) and von Willebrand factor (vWF) in dogs with babesiosis is unknown.

OBJECTIVES

Whether inflammation in babesiosis triggers activation of ICAM-1 and the coagulation system.

ANIMALS

Twelve and 10 dogs with naturally occurring babesiosis before and after antiparasitic treatment, respectively, were compared with 10 healthy dogs.

METHODS

In this prospective study, diagnosis was made by blood smear examination and confirmed by PCR. C-reactive protein (CRP), soluble intercellular adhesion molecule 1 (sICAM-1), and von Willebrand factor (vWF) levels were measured by a canine ELISA kit, fibrinogen (FIB) and factor VIII activity levels were measured by coagulometric methods, and blood cell counts (WBC, RBC, PLT) were determined with an automatic analyzer.

RESULTS

Compared to healthy dogs, the CRP, sICAM-1, and FIB concentrations were significantly increased before therapy and remained high for 3 days after therapy in dogs with babesiosis. vWF activity was significantly decreased in dogs with babesiosis before treatment. FVIII activity did not differ between dogs with babesiosis and healthy dogs. WBC; RBC and PLT were significantly lower before treatment and normalized by 3 days after treatment.

CONCLUSION AND CLINICAL IMPORTANCE

A proinflammatory condition in babesiosis appears to influence endothelial dysfunction and hemostatic activity. Although clearly beneficial for the parasite, sequestered blood cells can obstruct blood flow in small vessels, promote an inflammatory state, and could increase the severity of babesiosis.

Mild hemophilia A

Mild hemophilia A (HA), defined by clinical features and factor VIII coagulant activity (FVIII:C) between 0.05 and 0.40 IU mL(-1), is characteristically distinct from severe HA. Indeed, although the molecular characterization of mild HA has permitted the identification of specific underlying mutations, its clinical phenotype is strikingly different from that of patients with a severe FVIII defect, where spontaneous hemorrhages or recurrent joint bleeding are usual manifestations. With aging, mild HA patients may develop complications (i.e. cancers and cardiovascular disorders), the management of which may prove challenging due to the concomitant bleeding tendency. Furthermore, the development of inhibitors provides an additional major complication in these patients, because it increases the severity of the bleeding phenotype and complicates their management. Standard management of mild HA includes the use of desmopressin and antifibrinolytic agents for minor bleeding episodes or surgical procedures, whilst major bleeding or surgery requires replacement therapy with FVIII concentrates. As regards treatment of patients with inhibitors, bypassing agents (i.e. activated prothrombin complex concentrates and recombinant activated FVII) have proven effective in the treatment of bleeding episodes, but as there are insufficient data to determine the optimal approach to immune tolerance induction in this group of patients, their optimal management remains controversial. Rituximab is a newer, promising therapeutic option for inhibitor eradication in such patients. Many aspects concerning mild HA remain to be clarified, including the molecular basis, the natural history and the optimal diagnostic and therapeutic strategies. Only large prospective studies will shed light on this condition.

Early events in kidney donation: progression of endothelial activation, oxidative stress and tubular injury after brain death

Cerebral injury leading to brain death (BD) causes major physiologic derangements in potential organ donors, which may result in vascular-endothelial activation and affect posttransplant graft function. We investigated the kinetic of pro-coagulatory and pro-inflammatory endothelial activation and the subsequent oxidative stress and renal tubular injury, early after BD declaration. BD was induced by slowly inflating a balloon-catheter inserted in the extradural space over a period of 30 min. Rats (n = 30) were sacrificed 0.5, 1, 2 or 4 h after BD-induction and compared with sham-controls. This study demonstrates immediate pro-coagulatory and pro-inflammatory activation of vascular endothelium after BD in kidney donor rats, proportional with the duration of BD. E- and P-Selectins, Aalpha/Bbeta-fibrinogen mRNA were abruptly and progressively up-regulated from 0.5 h BD onwards; P-Selectin membrane protein expression was increased; fibrinogen was primarily visualized in the peritubular capillaries. Plasma von Willebrand factor was significantly higher after 2 h and 4 h BD. Urine heart-fatty-acid-binding-protein and N-acetyl-glucosaminidase, used as new specific and sensitive markers of proximal and distal tubular damage, were found significantly increased after 0.5 h, with a maximum at 4 h. Unexpectedly, oxidative stress was detectable only late, after the installation of tubular injury, suggesting only a secondary role for hypoxia in triggering these injuries.

Correlation between von Willebrand factor antigen, von Willebrand factor ristocetin cofactor activity and factor VIII activity in plasma

BACKGROUND

The laboratory diagnosis of von Willebrand Factor (VWF) deficiencies includes qualitative and quantitative measurements of VWF and clotting factor VIII (FVIII). Since the FVIII activity is frequently normal in patients with mild type 1 or 2 von Willebrand disease (VWD), there is controversy whether FVIII testing should accompany VWF Antigen (VWF:Ag) assay.

METHODS

The aim of this study was to explore the correlation between VWF:Ag, VWF ristocetin cofactor activity (VWF:RCo) and FVIII in 213 consecutive patients undergoing screening for VWD.

RESULTS

Forty-six patients were identified with VWF:Ag levels lower than the diagnostic threshold (54 IU/dl). A significant correlation was observed between VWF:Ag and VWF:RCo (r = 0.892; p < 0.001), VWF:Ag and FVIII (r = 0.834; p < 0.001), VWF:RCo and FVIII (r = 0.758; p < 0.001). Receiver operating characteristic curve analysis of the VWF:Ag assay revealed an area under the curve of 0.978 and 0.957 for detecting life-threatening values of FVIII (<30 IU/dl) and VWF:RCo (<40 IU/dl), respectively. The negative and positive predictive values at the VWF:Ag threshold value of 54 IU/dl were 100% and 33% for detecting life-threatening FVIII deficiencies, 94% and 80% for identifying abnormal values of VWF:RCo.

CONCLUSIONS

Due to the excellent correlation between VWF:Ag and FVIII and to the diagnostic efficiency of VWF:Ag for identifying abnormal FVIII levels in patients with VWF deficiency, routine measurement of FVIII may not be necessary in the initial screening of patients with suspected VWD. However, the limited negative predictive value of VWF:Ag for identifying type 2 VWD does not allow to eliminate VWF:RCo or VWF:FVIIIB assays from the diagnostic workout.

The significance of evaluating conventional inflammatory markers in Von Willebrand factor measurement

BACKGROUND

The appropriate clinical interpretation of Von Willebrand factor (VWF) measurements is crucial since inherited or acquired deficiencies are responsible for a potentially life threatening bleeding disorder, whereas increased plasma concentrations may be associated with an increased thrombotic risk. Besides age and blood group, the variability introduced by the presence of an acute phase response might contribute to decrease the clinical usefulness of this measurement.

METHODS

To investigate the relationship between conventional inflammatory markers and VWF, 387 consecutive unselected patients undergoing surgical procedures at our University Hospital were systematically investigated for routine laboratory testing, including also VWF Antigen (VWF:Ag), C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) as parts of a routine preoperative screening program.

RESULTS

After stratifying the study population according to the upper limit of the reference range of the two inflammatory markers, a significantly increased median VWF:Ag plasma concentration was observed for subjects with increased value of both CRP (CRP>5 mg/L=VWF:Ag>120 UI/dL; CRP<5 mg/L=VWF:Ag 98 UI/dL, p=0.003) and ESR (ESR>30 mm/hg=VWF:Ag>120 UI/dL; ESR<30 mm/hg=VWF:Ag 96 UI/dL, p<0.001). A significantly different frequency distribution of VWF:Ag concentrations was also observed in subjects with values of inflammatory markers above the upper limits of the reference ranges when compared to those with normal values. In particular, the prevalence of subjects with VWF:Ag levels>120 UI/dL was six- and nearly three-times higher in subjects with abnormal values of CRP (55.8% versus 9.3%, p<0.001) and ESR (54.5% versus 18.7%, p<0.001), respectively.

CONCLUSIONS

Results of this investigation demonstrate that the evaluation of conventional inflammatory markers would represent a valuable tool to enhance the clinical usefulness of VWF measurements, especially in patients with transitory and subclinical inflammation. Since VWF and factor VIII are likely to increase in parallel, we suggest that their measurements should be repeated at least after 6 months to one year in the presence of concomitantly increased values of inflammatory markers, such as ESR and/or CRP.

Is the activated partial thromboplastin time suitable to screen for von Willebrand factor deficiencies?

The diagnostic approach to von Willebrand factor deficiencies is challenging and requires discretionary use of laboratory resources. Although extensive preoperative testing is not recommended, the activated partial thromboplastin time may be useful, especially in selected categories of patients. To establish the diagnostic sensitivity of this test to identify isolate von Willebrand factor deficiencies, 204 consecutive patients underwent a routine preoperative screening consisting of activated partial thromboplastin time, von Willebrand factor antigen, intrinsic pathway clotting factors activity, lupus anticoagulants and thrombin time. Thirty-seven patients were diagnosed with haemostasis disturbances other than von Willebrand factor deficiencies and were excluded from the evaluation. Isolated von Willebrand factor deficiency was diagnosed in 11 of the remaining 167 patients. A significant correlation was observed between von Willebrand factor antigen and activated partial thromboplastin time. Receiver operating characteristic curve analysis showed an area under the curve of 0.982 (95% confidence interval: 0.972-0.992; P < 0.001). At the 1.17 upper limit of the activated partial thromboplastin time, sensitivity and specificity were 100 and 85%, respectively, with negative and positive predictive values of 100 and 31%, respectively. These results demonstrate that activated partial thromboplastin time has an excellent diagnostic sensitivity and a satisfactory specificity for identifying isolated von Willebrand factor deficiencies.