Management of von Willebrand disease: a survey on current clinical practice from the haemophilia centres of North America

Two cases of peritonsillar abscess complicated by von Willebrand disease

Von Willebrand disease (vWD) is a common hereditary bleeding disorder resulting from a quantitative and/or qualitative deficiency of von Willebrand factor (vWF). We report two cases of peritonsillar abscess complicated by vWD. A 46-year-old Japanese man was intravenously administered factor VIII clotting antigen (500U×3 days)and platelet transfusion (10U), when before puncture was performed. After puncture, his symptoms promptly improved with the administration of the antibiotic doripenem (DRPM, 1.5g/day). He left our facility one week later and had no recurrence of symptoms. A 24-year-old Japanese woman was intravenously administered factor VIII clotting antigen (4500U×3 days) and desmopressin (DDAVP) before undergoing a puncture. Her symptoms promptly improved with DRPM treatment (1.5g/day). The patient left our facility one week later. However, the peritonsillar abscess recurred in three weeks. Afterwards, tonsillectomy was enforced three months later. Intravenous factor VIII clotting antigen (4500U×2 days) and platelet transfusion (10U×1 day) had been used before tonsillectomy. We therefore suggest that a peritonsillar abscess in patients with vWD can be safely treated by factor VIII clotting antigen and DDAVP at the appropriate disease stage and by performing paracentesis for the acute phase or tonsillectomy for the chronic phase.

Desmopressin for the treatment of haemophilia

The synthetic vasopressin analogue (1-deamino-8-D-arginine-vasopressin) increases plasma concentration of factor VIII and von Willebrand factor in normal subjects and patients with mild haemophilia A and von Willebrand disease. Since its first clinical use in 1977, desmopressin has become the treatment of choice for patients with haemophilia A and factor VIII coagulant activity (FVIII:C) > 5% and has spared several patients the risk of acquiring blood-borne viral infections due to the use of non-virally inactivated plasma-derived FVIII concentrates. An average two to sixfolds FVIII:C increase is typically observed in most patients and return to baseline occurs usually within 8 hours. Several clinical studies have demonstrated the clinical efficacy and safety of desmopressin and the availability of concentrated formulation for subcutaneous injection and of a nasal spray has paved the way to home-treatment. However, overall it appears that haemophilic children may have a lower rate of biologic response compared to adults and a minority of adult patients are not able to attain clinically useful FVIII:C levels post-desmopressin administration. Thus, in every patient with haemophilia A likely to be treated or candidate to an elective invasive procedure, a test-infusion/injection should be carried out to assess the future usefulness of the compound.

von Willebrand factor/factor VIII concentrate (Haemate P) dosing based on pharmacokinetics: a prospective multicenter trial in elective surgery

BACKGROUND

While plasma-derived concentrates containing large amounts of von Willebrand factor (VWF) are effective in treating von Willebrand disease (VWD), optimal dosing remains to be fully characterized.

OBJECTIVES

To determine the feasibility of dosing Haemate P VWF/factor VIII (FVIII) concentrate based on pharmacokinetics (PK) in the management of surgical subjects with VWD.

METHODS

VWD subjects scheduled for elective surgery were enrolled in a prospective multicenter open-label cohort study. A pre-operative loading dose of VWF/FVIII concentrate based upon prior individual subject PK analysis was administered followed by postoperative therapeutic/maintenance infusions.

RESULTS

Twenty-eight subjects with types 1, 2A or 3 VWD and one with type 2 M were enrolled. Median in vivo recovery of VWF ristocetin cofactor (VWF:RCo) was 1.9 IU dL(-1) (IU kg(-1))(-1) with an interquartile range (IQR) of 1.6-2.5 IU dL(-1) (IU kg(-1))(-1). Median response, half-life and clearance were 74.0% (IQR, 55.5-100%), 15.6 h (IQR, 9.0-28.4 h) and 3.26 mL kg(-1) h(-1) (IQR, 2.29-5.21 mL kg(-1) h(-1)), respectively. A PK-guided median VWF:RCo loading dose of 62.4 IU kg(-1) (IQR, 50.1-87.0 IU kg(-1)) was administered. Postoperative mean trough VWF:RCo levels of 62-73 IU dL(-1) were sufficient to prevent bleeding. Investigators rated hemostasis excellent or good in 96.3% of subjects on the day of surgery and 100% on the next day and on day 14. A subject with multiple risk factors developed pulmonary embolism, which resolved without sequelae.

CONCLUSIONS

Haemate P provided effective and safe hemostasis in VWD subjects undergoing elective surgery. Selection of Haemate P loading dose on the basis of VWF PK proved feasible.

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.

The obstetric and gynaecological management of women with inherited bleeding disorders - review with guidelines produced by a taskforce of UK Haemophilia Centre Doctors' Organization

The gynaecological and obstetric management of women with inherited coagulation disorders requires close collaboration between obstetrician/gynaecologists and haematologists. Ideally these women should be managed in a joint disciplinary clinic where expertise and facilities are available to provide comprehensive assessment of the bleeding disorder and a combined plan of management. The haematologist should arrange and interpret laboratory tests and make provision for appropriate replacement therapy. These guidelines have been provided for healthcare professionals for information and guidance and it is also intended that they are readily available for women with bleeding disorders.

Identification and management of women with inherited bleeding disorders: a survey of obstetricians and gynaecologists in the United Kingdom

A mail survey of members and fellows of Royal College of Obstetricians and Gynaecologists was carried out to determine current practices of obstetricians and gynaecologists in the United Kingdom in the management of women with inherited bleeding disorders. In total, 3929 questionnaires were sent, 707 returned and analysis was limited to 545 valid questionnaires. In the past 5 years, 91% have managed women with inherited bleeding disorders. The majority (83%) considered inherited bleeding disorders to be under diagnosed in obstetrics and gynaecology. More than 80% considered the prevalence of von Willebrand's disease (VWD) to be <0.2% in the general population and <1% in women with menorrhagia and no gynaecological pathology, although the reported prevalence is 1% and 5-25% respectively. Twelve percent of the respondents would arrange testing for VWD when reviewing an 18-year-old with menorrhagia and no pelvic pathology, while only 2% would do the same for a 35-year-old with the same presentation. Twenty-one percent thought elective caesarean section is indicated in all fetuses known to be at risk of being affected by haemophilia. Eighty-four percent considered vacuum extraction unsafe in these cases, but 76% would consider the use of low forceps. In conclusion, obstetricians and gynaecologists underestimate inherited bleeding disorders as an underlying cause for menorrhagia. Increased awareness and management guidelines are essential in minimizing haemorrhagic complications and improving quality of care of these women.

The use of recombinant–activated factor VII in von Willebrand disease: a case series

Spontaneous and surgery-associated bleeding in patients with von Willebrand disease (vWD) cannot always be controlled with desmopressin or replacement therapy. This paper presents results on the use of recombinant-activated factor VII (rFVIIa) in patients with vWD included in the internet registry Haemostasis.com. Twenty-eight reports on the use of rFVIIa in vWD were identified from the database and included in this analysis. The bleeding episodes were classified as mild (n = 7), moderate (n = 16), or severe (n = 2), and were unspecified in three cases. The median dose of rFVIIa administered was 94 microg/kg body weight (40-127.3 microg/kg). Bleeding stopped in 23 of 27 evaluable patients (85%) and markedly decreased in three patients; the total response rate was 96% (26/27 patients). Response did not correlate with the type of vWD, the site or severity of the initial bleed, or the rFVIIa dose. Other replacement therapies were infrequently used, and their use was similar in the 24 h before and after rFVIIa administration. Eighteen patients also received antifibrinolytic treatment, but its impact on response was not recorded. Only one adverse event (mild fever) was observed. These cases suggest a role for rFVIIa as a safe and effective therapy for vWD.

von Willebrand's disease and menorrhagia: prevalence, diagnosis, and management

The reported prevalence of von Willebrand's disease (vWD) is increased in women with menorrhagia, with current estimates ranging from 5% to 20%. The consistent results of multiple studies suggest testing should be included in the evaluation of patients with menorrhagia, especially in unexplained cases and prior to surgical intervention. Although a cyclic variation in von Willebrand's factor levels has not been confirmed, several studies suggest lower levels during menses and the early follicular phase. Menorrhagia is one of the most common bleeding manifestations of von Willebrand's disease, reported by 60-95% of women afflicted with this bleeding disorder. Menorrhagia is typically severe, often resulting in anemia and interfering with quality of life. Despite the frequency of menorrhagia, there is no consensus on optimal management. Although oral contraceptives are frequently prescribed, there are no studies confirming their efficacy using objective measures of response. Desmopressin was associated with an 80-92% response rate in several uncontrolled studies relying on patient assessment of efficacy. However, a small, randomized trial found no significant reduction in menstrual blood flow compared with placebo. There are anecdotal reports of the successful use of antifibrinolytic agents alone and in combination with other therapies. There are no studies comparing the relative efficacy and safety of the available medical therapies for von Willebrand's disease associated menorrhagia. Until these studies are completed, treatment should be individualized based on von Willebrand's disease subtype, patient age, contraceptive needs, and personal preference.

Haemostatic management of intraoral bleeding in patients with von Willebrand disease

OBJECTIVES

To develop plans for the haemostatic management of intraoral bleeding in patients with von Willebrand disease (VWD).

SUBJECTS AND METHODS

Thirty-seven episodes of haemostatic management of intraoral bleeding in 19 VWD patients were analysed retrospectively based on the medical records.

RESULTS AND CONCLUSIONS

When performing tooth extractions in patients with type 1 or 2A VWD [responsive to 1-deamino-8-D-arginine-vasopressin (DDAVP)], 0.35-0.4 microg kg(-1) of DDAVP should be administered intravenously at three times. In patients with type 2A VWD (unresponsive to DDAVP) or patients with type 2B or 2N VWD, 50-90 U [as ristocetin cofactor (VWF:RCof)] kg(-1) of a factor VIII concentrate containing von Willebrand factor (FVIII/VWF concentrate) should be administered twice in routine extractions, and four to six times in surgical extractions. Gingival bleeding related to primary teeth can be mostly managed by pressure haemostasis alone. However, when treating gingival bleeding caused by marginal periodontitis, it is often necessary to administer 0.4 microg kg(-1) of DDAVP or 40-70 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. As local haemostasis is difficult to achieve in bleeding from the tongue or labial or mandibular haematoma, it is necessary to administer 0.4 microg kg(-1) of DDAVP or 60-80 U (as VWF:RCof) kg(-1) of a FVIII/VWF concentrate. In addition, oral administration of 20 mg kg(-1) day(-1) of tranexamic acid should be combined with the regimens described above.

A triple-blinded randomized trial comparing the hemostatic effects of large-dose 10% hydroxyethyl starch 264/0.45 versus 5% albumin during major reconstructive surgery

In Canada, hydroxyethyl starch 264/0.45 (HES 264/0.45; molar weight 264 kDa, molar substitution 0.45) has largely replaced albumin as the colloidal fluid of choice for perioperative intravascular volume expansion. The maximum recommended dose of HES 264/0.45 is 28 mL/kg; however, there are no clinical data supporting this limit. In this study we compared the hemostatic effects of HES 264/0.45 versus 5% albumin in doses up to 45 mL/kg over 24 h during major reconstructive head and neck surgery. Fifty patients were randomized to receive HES 264/0.45 or 5% human albumin from the induction of anesthesia until 24 h thereafter. Both albumin and HES 264/0.45 effectively maintained physiologic variables in the perioperative and postoperative periods. The partial thromboplastin time and international normalized ratio were significantly increased in the HES 264/0.45 group compared with the albumin group after infusion of 30 mL/kg and 45 mL/kg (P < 0.05). Factor VIII activity and von Willebrand factor level were significantly reduced in the HES 264/0.45 group compared with the albumin group after infusion of 15 mL/kg, 30 mL/kg, and 45 mL/kg (P < 0.05). Significantly more subjects in the HES 264/0.45 group received allogeneic red blood cell transfusions (P < 0.02). We conclude that HES 264/0.45 infusions >30 mL/kg over 24 h impair coagulation to a greater extent than albumin, possibly leading to more allogeneic transfusions.

Diagnosis and treatment of von Willebrand disease

Von Willebrand disease (VWD) is the most common bleeding disorder; it is believed to occur in approximately 1% to 2% of the population. Mucocutaneous and surgical hemorrhage in affected individuals is caused by quantitative and qualitative defects in von Willebrand factor (VWF), a large, multimeric protein that supports platelet adhesion and aggregation in the initiation of hemostasis at the time of vascular injury and functions as a carrier protein for factor VIII in the circulation. Advances in cellular and molecular biology have led to improved understanding of the pathophysiology of the disorder and development of a classification scheme that is based on quantitative and qualitative defects. Effective treatment is dependent on an accurate diagnosis using specific assays of VWF that define the various defects.

A practical concept for preoperative management of patients with impaired primary hemostasis

In a prospective study, 254 of 5649 unselected patients scheduled for surgery at our hospital were identified preoperatively as having either acquired (n=182) or inherited (n=72) impaired primary hemostasis (platelet dysfunction including von Willebrand disease). All patients were initially pretreated with desmopressin (DDAVP). Response to DDAVP or subsequent treatment(s) was defined as correction of any one of the abnormal PFA-100 platelet function tests. The non-responders were additionally treated with tranexamic acid or aprotinin; those with von Willebrand disease (vWD) received factor VIII concentrates with von Willebrand factor (vWF). Those still unresponsive to therapy received conjugated estrogens and, as a last attempt, a platelet transfusion. The administration of DDAVP led to a correction of platelet dysfunction in 229 of the 254 patients treated (90.2%). Tranexamic acid was effective in 12 of 16, aprotinin in 3 of 5, and factor VIII concentrates with vWF in all 4 patients with unresponsive to DDAVP. The remaining 6 patients were pretreated with conjugated estrogens, and 2 of these patients were additionally treated with platelet transfusion. The frequency of blood transfusion was lower, but not statistically significant (9.4% vs. 12.2%: p = 0.202) in preoperatively treated patients with impaired hemostasis than in patients without impaired hemostasis. In a retrospective group, the frequency of blood transfusion was statistically significant higher (89.3% vs. 11.3%: p < 0.001) in patients without preoperative correction of impaired hemostasis than in patients without impaired hemostasis. Preoperative correction of impaired primary hemostasis is possible in nearly all patients affected, and results in a reduction of homologous blood transfusions.

Content and functional activity of von Willebrand factor in apheresis plasma

BACKGROUND AND OBJECTIVES

Von Willebrand Factor (VWF) is a complex high-molecular-weight (HMW) plasma glycoprotein playing a critical role in primary and secondary haemostasis. Owing to its multimeric structure and sensitivity to proteolysis, VWF can be used as a marker of the impact of collection procedures on the characteristics of plasma for transfusion and for fractionation. We studied VWF content, functional activity and HMW multimers in plasmas collected by five different automated apheresis collection procedures.

MATERIALS AND METHODS

Five series of 30 plasma units were obtained from volunteer donors at two collection sites using Haemonetics PCS2 machines with Revision (Rev) F, Rev G, high-separation core (HSC), or filter core (FC) procedures, or Baxter-Fenwall Autopheresis-C (Auto-C). VWF antigen (VWF:Ag), ristocetin cofactor (VWF:RCo) activity and HMW multimers were first determined in 10 randomly selected plasma donations collected with Rev G, HSC, FC and Auto-C procedures. Then, the same analyses and the collagen binding (VWF:CB) activity were determined in the pools of 30 donations from each of the five procedures and compared with two normal plasma pools (NPP1 and NPP2). A reference plasma (RP) was used to calibrate each assay.

RESULTS

There were a greater number of group O individuals in the Rev F, Rev G and FC donors than in the HSC and Auto-C donors. The mean VWF:Ag level was > 100 IU/dl, VWF:RCo activity was > 90 U/dl, the VWF:RCo/Ag ratio was close to 1, and the percentage of 11-15 mers was above 100% of RP in the 10 individual plasma units from Rev G, HSC, FC, and Auto-C and in their respective pools. The mean percentage of multimers > 15 mers, relative to RP, was significantly less in Rev G plasmas (48 +/- 17%; range 32-91%), compared with Auto-C, HSC and FC plasmas (P = 0.0211; 0.0257; and 0.0376, respectively). The VWF:CB activity of the 30-donation pools was 61 and 60 U/dl in Auto C and HSC, 50 U/dl in Rev F and FC, and 43 U/dl in the Rev G pool. The VWF:CB/Ag ratio was 0.54 (Auto-C), 0.49 (HSC), 0.46 (Rev F), 0.45 (FC) and 0.37 (Rev G), compared with 0.81and 0.92 in NPPs. The percentage of VWF multimers of 11-15 mers in apheresis plasma and NPP was normal. VWF multimers > 15 mers ranged from 38 to 64% of that of RP plasma, and was 111 and 112% in NPPs.

CONCLUSIONS

The VWF:Ag, VWF:RCo activity and 11-15 mer VWF multimers were well preserved in all plasma units from each of the five apheresis procedures. The VWF:CB activity and the percentage of multimers > 15 mers in apheresis plasma was less than in normal plasma pools and differed slightly among procedures.

Type 3 von Willebrand disease: assessment of complications and approaches to treatment - results of a patient and Hemophilia Treatment Center Survey in the United States

It has been reported many times that the optimal treatment of patients with von Willebrand disease (VWD) has yet to be determined. To assist in achieving this goal, the aim of this survey was as follows: to collect information on current treatment practices; to determine the impact of the disease in type 3 VWD patients in the USA and to gain insight into the perceived and actual role that prophylaxis therapy plays in patient management. Nurse coordinators of the 146 federally funded Hemophilia Treatment Centers (HTCs) in the USA were contacted and informed of the survey and its goals. Those caring for type 3 VWD patients and willing to participate in the survey were mailed two questionnaires. The first questionnaire addressed the overall VWD patient population at their centre and asked questions relating to treatment practices. The second questionnaire focused on the impact that type 3 VWD has upon a patient's life. Thirty-four centres responded to the survey, providing a 48% response rate within the available pool of those centres treating type 3 VWD patients. Seventy-nine patients, with a mean age of 24.2 years, reported their primary causes of bleeding as; epistaxis (53.9%); joint bleeds (40.9%); dental bleeds (27.6%) and heavy menstrual bleeding (23.7%). There were a mean number of 9.2 reported non-life-threatening bleeds per year and a mean of 0.7 reported life-threatening bleeds per year. Forty percent reported lost days from school or work, caused by bleeds or other VWD complications. Sixty-two percent reported no joint damage. Regarding current treatment practices, 88.6% of respondents stated that their centre treated on demand and 13.9% used a prophylactic treatment regimen. Seventy-three percent of respondents felt that prophylaxis was either very or extremely helpful. This survey helps to document current treatment practices and morbidity exhibited by type 3 VWD patients. The results highlight the discrepancy between the use of prophylactic therapy, its perceived value and the level of joint damage and other morbidity experienced in this population.

Desmopressin (DDAVP) responsiveness in children with von Willebrand disease

PURPOSE

To determine the pattern and predictors of response to desmopressin (DDAVP) in children with von Willebrand disease (VWD).

METHODS

The authors reviewed the hospital records of all children with type 1 (n = 70) and type 2A (n = 5) VWD who were followed in the institution's Bleeding Disorders Clinic from January 1989 to June 2001 and who had a DDAVP challenge test after diagnosis. The major outcome evaluated was response to DDAVP, defined as an increase of greater than twofold over baseline of von Willebrand factor, ristocetin cofactor (VWF:RCo), and factor VIII coagulant (FVIII:C) and levels above 0.3 IU/mL.

RESULTS

Response to DDAVP was observed in 56 (80%) of the 70 children with type 1 VWD. Age and baseline VWF:RCo and FVIII:C levels were positively associated with DDAVP response. A total of 36 children (28 responders, 8 nonresponders) with type 1 VWD were treated for bleeding episodes or for prophylaxis; of these 75% (6/8) of the nonresponders compared with 7% (2/28) of the responders to a DDAVP challenge test received blood component therapy (P < 0.01). One of the five children with type 2A VWD responded to DDAVP.

CONCLUSIONS

DDAVP challenge tests are recommended in children with newly diagnosed VWD to identify responders in whom DDAVP may be used for the prevention or treatment of bleeding, thus avoiding exposure to blood products. The association of DDAVP response with age merits further investigation.

Effect of desmopressin acetate administration on primary hemostasis in Doberman Pinschers with type-1 von Willebrand disease as assessed by a point-of-care instrument

OBJECTIVE

To evaluate primary hemostasis following administration of desmopressin acetate (DDAVP) to Doberman Pinschers with type-1 von Willebrand disease (vWD).

ANIMALS

16 nonanemic Doberman Pinschers with type-1 vWD.

PROCEDURE

Closure time (CT), defined as time required for occlusion of an aperture by a platelet plug assessed within the point-of-care instrument, plasma von Willebrand factor (vWF) concentration, and buccal mucosal bleeding time (BMBT) were determined before and 1 hour after administration of DDAVP (1 microg/kg, SC).

RESULTS

Baseline closure times measured with adenosine diphosphate ([ADP-CT], 108 to > 300 seconds; reference range, 52 to 86 seconds) and epinephrine ([EPI-CT], 285 to > 300 seconds; 97 to 225 seconds) as platelet agonists were prolonged in all dogs. Following DDAVP administration, ADP-CT (59 to 186 seconds) was significantly shortened from baseline, but there was no decrease in EPI-CT. Although mean plasma vWF concentration increased significantly after DDAVP administration, only 1 dog had an increase of > 35 U/dL. There was no correlation between increase in plasma vWF concentration and shortening of the ADP-CT. Baseline BMBT was prolonged in 12 of 14 dogs, with significant shortening of BMBT after DDAVP administration in 6 of 7 dogs. In vitro replacement of vWF-deficient plasma with plasma from an unaffected dog shortened the ADP-CT whereas in vitro addition of DDAVP had no effect.

CONCLUSIONS AND CLINICAL RELEVANCE

Administration of DDAVP to Doberman Pinschers with type-1 vWD resulted in improved hemostatic function, as assessed by the point-of-care instrument and shortening of BMBT, despite minimal increase in plasma vWF concentration.

Menorrhagia from a haematologist's point of view. Part II: management

The management of menorrhagia has until recently been the domain of the gynaecologist. As haematologists, we are now addressing the issue of optimal management of menorrhagia in our patients with bleeding disorders. Addressing three life periods, the menarche, reproductive years, and postchildbearing years, this review will discuss the use of oral contraceptive agents, antifibrinolytics, non-steroidal anti-inflammatory drugs, intranasal DDAVP and the new levonorgestrel-impregnated IUD. Management of specific bleeding disorders will also be reviewed for von Willebrand disease, haemophilia A and B carriers, women with factor XI deficiency and PAI-1 deficiency.

Menorrhagia from a haematologist's point of view. Part I: initial evaluation

The evaluation of menorrhagia should no longer be solely the task of the gynaecologist. In women with ovulatory bleeding (regular cycles), the prevalence of von Willebrand disease (vWD) in about 15% of these, as well as disorders of platelet function and fibrinolysis causing menorrhagia, warrants an active role by the haematologist. Initial intake should include documentation of menorrhagia by the pictorial chart assessment of menstrual flow. Baseline characteristics of menstrual flow should also be documented, including the frequency of changing the sanitary pad on the heaviest day, use of more than one sanitary pad at a time, number of days lost from school/work and the impact of menses on various quality-of-life parameters. Menorrhagia since menarche, a past history of surgical- and/or dental-related bleeding and a past history of postpartum haemorrhage are items of the bleeding symptom audit that appear in part to predict vWD in women with menorrhagia. Epistaxis and easy bruising do not appear to be clearly discriminatory symptoms. Initial testing should include the complete blood cell count, prothrombin time, activated partial thromboplastin time, iron profile, serum creatinine, thyroid stimulating hormone level, factor VIII level, vWF antigen, ristocetin cofactor and platelet aggregation studies. Additional haemostatic studies may also include a factor XI level and euglobulin clot lysis time. This extensive medical evaluation should assure both the patient and the gynaecologist that the possibility of an underlying haemostatic disorder has been thoroughly investigated, to avoid the patient undergoing further costly procedures and surgical interventions if an underlying haemostatic disorder remains unrecognized.

Use of ristocetin cofactor activity in the management of von Willebrand disease

von Willebrand disease (vWD), the most common of the hereditary bleeding disorders, arises from quantitative or qualitative defects in von Willebrand factor (vWF). vWF is a multimeric plasma protein that plays a key role in primary and secondary haemostasis. In the current classification scheme, vWD is divided into six subtypes that are based on the nature of the vWF defect. Therapeutic strategies depend on the accurate identification of these subtypes. In most clinical situations, desmopressin is effective treatment for the great majority of patients with mild (type 1) disease, while replacement therapy with factor VIII/vWF concentrates that contain high levels of vWF activity is required for most type 2 and nearly all type 3 vWD patients. Several factor VIII/vWF replacement products are available, one of which (Humate P) has been approved for the treatment of vWD by the US Food and Drug Administration. Preliminary results of recent studies support the hypothesis that treatment with factor VIII/vWF concentrates based upon the content of vWF activity as reflected in the ristocetin cofactor assay is practicable, safe and efficacious. The establishment of optimal treatment regimens with respect to dose intensity and duration will require further study.