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

Abstract

The optimal treatment of patients with von Willebrand's disease (vWD) remains to be defined. Moreover, it has not been firmly established which, if any, commonly measured parameters of von Willebrand factor (vWF) protein in the plasma are useful in guiding treatment. To better understand what guidelines physicians follow in the management of vWD, we surveyed 194 North American physicians who are members of the Hemophilia Research Society. Ninety-nine per cent of responding physicians depend on factor VIII (FVIII):C, vWF:RCo activity and vWF:AG to diagnose vWD, while only 49% use the bleeding time. The minimal goals of treatment for patients undergoing major surgery/trauma or central nervous system haemorrhage were FVIII:C and vWF:RCo activity greater than 80% while levels of more than 50% for minor surgery and dental extractions were considered adequate. Treatment of vWD was based on the type of vWD with type 1 patients being treated most often with desmopressin acetate (DDAVP) alone, types 2A and 2B patients with a combination of DDAVP and a vWF-containing FVIII product, type 3 patients with vWF-containing concentrate. Viral infections, including human immunodeficiency virus, hepatitis A, B and C viruses, and parvovirus have been seen in vWD and the efficacy of viral attenuation processes is a major criterion for the selection of treatment by physicians. Based on this survey, prospective studies need to be designed to address the clinical efficacy, safety and predictive value of laboratory monitoring of patients with vWD.

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

“…Since the minimal goal of treatment for patients undergoing surgery and dental extractions is VWF activities greater than 50% [16], the primary outcome of our investigation was to establish whether a sensitive micronized silica reagent for the aPTT may be suitable to identify isolated VWF deficiencies that may be associated with a clinically significant perioperative bleeding. To our knowledge, this is the first study looking specifically at the correlation between VWF:Ag in plasma and aPTT in a clinical preoperative setting.…”

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

“…DDAVP can be administered intravenously, subcutaneously, or as a nasal spray, convenient for outpatient treatment of minor bleeding episodes. In one survey, 86% of hematologists reported using intranasal DDAVP for menorrhagia in women with type 1 vWD [52]. Despite the increasing use of DDAVP for this problem, there is limited evidence supporting its efficacy (Table II).…”

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

“…Treatment of vWD is partly based on the type of disease, with type 1 usually being treated with desmopressin acetate, type 2A with a combination of desmopressin acetate and vWF-containing factor VIII (FVIII) product, and type 3 with vWF-containing concentrate [5]. The use of desmopressin acetate in type 2B is controversial because it induces platelet aggregation [6].…”

“…Antifibrinolytic agents such as e-aminocaproic acid are sometimes used as adjuncts, especially for mucosal bleeding [7]. The efficacy of these treatments has been difficult to assess, as treatment endpoints are poorly defined -vWF levels do not correlate with bleeding [7], and bleeding times may be misleading [5]. Furthermore, randomized, placebo-controlled trials are rare and use small numbers of patients (for example, [8]).…”