Management of elective procedures in low von Willebrand factor patients in the LoVIC study

Type 1 VWD classification revisited: novel insights from combined analysis of the LoVIC and WiN studies

ABSTRACT

There is significant ongoing debate regarding type 1 von Willebrand disease (VWD) defintion. Previous guidelines recommended patients with von Willebrand factor (VWF) levels <30 IU/dL be diagnosed type 1 VWD, whereas patients with significant bleeding and VWF levels from 30 to 50 IU/dL be diagnosed with low VWF. To elucidate the relationship between type 1 VWD and low VWF in the context of age-induced increases in VWF levels, we combined data sets from 2 national cohort studies: 162 patients with low VWF from the Low VWF in Ireland Cohort (LoVIC) and 403 patients with type 1 VWD from the Willebrand in The Netherlands (WiN) studies. In 47% of type 1 VWD participants, VWF levels remained <30 IU/dL despite increasing age. Conversely, VWF levels increased to the low VWF range (30-50 IU/dL) in 30% and normalized (>50 IU/dL) in 23% of type 1 VWD cases. Crucially, absolute VWF antigen (VWF:Ag) levels and increase of VWF:Ag per year overlapped between low VWF and normalized type 1 VWD participants. Moreover, multiple regression analysis demonstrated that VWF:Ag levels in low VWF and normalized type 1 VWD patients would not have been different had they been diagnosed at the same age (β = 0.00; 95% confidence interval, -0.03 to 0.04). Consistently, no difference was found in the prevalence of VWF sequence variants; factor VIII activity/VWF:Ag or VWF propeptide/VWF:Ag ratios; or desmopressin responses between low VWF and normalized type 1 VWD patients. In conclusion, our findings demonstrate that low VWF does not constitute a discrete clinical or pathological entity. Rather, it is part of an age-dependent type 1 VWD evolving phenotype. Collectively, these data have important implications for future VWD classification criteria.

Desmopressin (DDAVP) use in patients with von Willebrand disease: A single-centre retrospective review of test response and clinical outcomes

INTRODUCTION

Peri-procedural management of von Willebrand disease (VWD) utilizes von Willebrand factor (VWF) concentrates or desmopressin (DDAVP) to increase VWF levels. DDAVP is safe, easily administered, and inexpensive. Currently, a consensus definition for adequate DDAVP response is lacking, and outcomes of peri-procedural DDAVP use in VWD patients are seldom reported.

AIM

This single-centre retrospective review aims to characterize DDAVP-responsiveness and assess clinical outcomes of peri-procedural DDAVP use in VWD.

PATIENTS AND METHODS

We reviewed records for all our adult VWD patients (age ≥18 years) who underwent DDAVP challenge testing between January 2007 and January 2022. DDAVP-responsiveness was assessed using six definitions. Bleeding outcomes following procedures covered by DDAVP were classified as excessive or expected bleeding.

RESULTS

Eighty-four of 94 (89.4%) patients were DDAVP-responsive by our definition (1-h VWF Activity/Factor VIII ≥0.50 IU/mL). However, the proportion of DDAVP-responders varied from 53.2% to 91.5%, depending on the literature definition used. Ninety-nine procedures pre-treated with DDAVP were performed during the study period. Eighty-six (86.7%) procedures (31 major; 55 minor) were covered with only DDAVP ± tranexamic acid (TXA). Excessive bleeding occurred following 4/31 major procedures and 2/55 minor procedures (both performed in a single patient with a bleeding score of 16). When covered with DDAVP+Factor ± TXA, one each of 10 major and 3 minor procedures (performed in 2 patients with bleeding scores 15-16) resulted in post-procedural bleeding.

CONCLUSIONS

Peri-procedural DDAVP prophylaxis appears to be effective among individuals with VWD. Beyond DDAVP-responsiveness, patient bleeding history and procedure invasiveness should be considered in determining suitability for DDAVP prophylaxis.

Enhanced VWF clearance in low VWF pathogenesis: limitations of the VWFpp/VWF:Ag ratio and clinical significance

Increased von Willebrand factor (VWF) clearance plays a key role in the pathogenesis of type 1 and type 2 von Willebrand disease (VWD). However, the pathological mechanisms involved in patients with mild to moderate reductions in plasma VWF:Ag (range, 30-50 IU/dL; low VWF) remain poorly understood. In this study, we investigated the hypothesis that enhanced VWF clearance may contribute to the pathobiology of low VWF. Patients with low VWF were recruited to the LoVIC study after ethics approval and receipt of informed consent. Desmopressin was administered IV in 75 patients, and blood samples were drawn at baseline and at the 1-hour and 4-hour time points. As defined by recent ASH/ISTH/NHF/WFH guidelines, 20% of our low-VWF cohort demonstrated significantly enhanced VWF clearance. Importantly, from a clinical perspective, this enhanced VWF clearance was seen after desmopressin infusion, but did not affect the steady-state VWF propeptide (VWFpp)-to-VWF antigen (VWF:Ag) ratio (VWFpp/VWF:Ag) in most cases. The discrepancy between the VWFpp/VWF:Ag ratio and desmopressin fall-off rates in patients with mild quantitative VWD may have reflected alteration in VWFpp clearance kinetics. Finally, bleeding scores were significantly lower in patients with low VWF with enhanced VWF clearance, compared with those in whom reduced VWF biosynthesis represented the principle pathogenic mechanism. This trial was registered at http://www.clinicaltrials.gov as #NCT03167320.

Beyond the guidelines: how we approach challenging scenarios in the diagnosis and management of von Willebrand disease

Although von Willebrand disease (VWD) is the most common inherited bleeding disorder, its diagnosis and management are often challenging. Clinical practice guidelines, developed through systematic review of the medical literature and considering the best available evidence, provide guidance for common clinical scenarios. However, in the clinical setting, patients often present with characteristics and nuances that may fall outside the realm of available evidence and guidelines, and hence, shared decision-making will be essential in the evaluation and management of these patients. The challenges in the diagnosis of VWD are mainly attributable to the heterogeneity of the disorder, limitations of laboratory assays, and the significant impact of various physiologic processes on von Willebrand factor. The impact of physiologic normalization of von Willebrand factor, which may occur in various settings such as pregnancy, inflammation, or aging, remains uncertain, as is the optimal management in these scenarios. Multidisciplinary and individualized care, based on evolving evidence supported by clinicians, patients, caregivers, and stakeholders, will be needed to ensure the highest quality care for those who live with VWD.

Low von Willebrand Disease: A Bleeding Disorder of Unknown Cause?

von Willebrand disease (VWD) represents the most common inherited bleeding disorder. The majority of VWD cases are characterized by partial quantitative reductions in plasma von Willebrand factor (VWF) levels. Management of patients with mild to moderate VWF reductions in the range of 30 to 50 IU/dL poses a common clinical challenge. Some of these low VWF patients present with significant bleeding problems. In particular, heavy menstrual bleeding and postpartum hemorrhage can cause significant morbidity. Conversely, however, many individuals with mild plasma VWF:Ag reductions do not have any bleeding sequelae. In contrast to type 1 VWD, most patients with low VWF do not have detectable pathogenic VWF sequence variants, and bleeding phenotype correlates poorly with residual VWF levels. These observations suggest that low VWF is a complex disorder caused by variants in other genes beyond VWF. With respect to low VWF pathobiology, recent studies have shown that reduced VWF biosynthesis within endothelial cells likely plays a key role. However, pathological enhanced VWF clearance from plasma has also been described in approximately 20% of low VWF cases. For low VWF patients who require hemostatic treatment prior to elective procedures, tranexamic acid and desmopressin have both been shown to be efficacious. In this article, we review the current state of the art regarding low VWF. In addition, we consider how low VWF represents an entity that appears to fall between type 1 VWD on the one hand and bleeding disorders of unknown cause on the other.

Perioperative Outcomes of Patients with Bleeding Disorders Undergoing Major Surgery at an Academic Hemophilia Treatment Center

Persons with bleeding disorders (PwBD) are at high risk for bleeding with invasive procedures. However, the risk of bleeding in PwBD undergoing major surgery and outcomes of patients managed perioperatively at a hemophilia treatment center (HTC) are not well described. We performed a retrospective review of surgical outcomes among PwBD undergoing major surgery between January 1st, 2017 and December 31st, 2019 at the Cardeza Foundation Hemophilia and Thrombosis Center in Philadelphia, PA. The primary outcome was postoperative bleeding, assessed according to the ISTH-SSC's 2010 definition. Secondary outcomes included use of unplanned postoperative hemostatic therapy, LOS, and 30-day readmission rate. Results were compared to non-PwBD population from a surgical database, matched for surgery, age, and sex. During the study period, 50 PwBD underwent 63 major surgeries. The most common diagnoses were VWD (64%) and hemophilia A (20.0%). The most common surgical procedure category was orthopedic (33.3%), predominantly arthroplasties. Postoperatively,4.8% of procedures were complicated by major bleeding and 1.6% by non-major bleeding. The mean LOS was 1.65 days, and 30-day readmission rate was 1.6%. In comparison to matched, non-PwBD patients in a national surgical database undergoing the same procedures, study patients had a similar rate of bleeding complications per procedure (5.0% vs 1.04% P = .071, Fisher's exact test). PwBD undergoing major surgeries have low rates of major bleeding when receiving comprehensive care at an HTC. Bleeding and hospital readmission rates were similar to non-PwBD baseline in a large database.

Diagnostic pitfalls and conundrums in type 1 von Willebrand disease

Most people with von Willebrand disease (VWD) have a partial quantitative deficiency of plasma von Willebrand factor (VWF) or type 1 VWD. In contrast to type 2 and type 3 VWD, laboratory assays will not always establish the diagnosis in type 1 VWD. This is because plasma VWF levels in type 1 VWD, especially those with levels closer to 50 IU/dL, overlap with the general population. Assessment is further complicated by increased plasma VWF levels in response to physiologic stressors or aging. Diagnosis of those with type 1 VWD with plasma VWF levels 30 to 50 IU/dL (previously referred to as "low VWF") requires expert assessment of bleeding phenotype as well as an understanding of the limitations of both bleeding assessment tools (BATs) and laboratory testing. Using the available evidence and highlighting research gaps, we discuss common dilemmas facing providers relating to assessment of adolescents, transition from pediatrics to adult care, and older individuals with type 1 VWD.

Bleeding disorders in implant dentistry: a narrative review and a treatment guide

Purpose

Considering a high prevalence of congenital and especially acquired bleeding disorders, their heterogeneity and the multitude of possible treatments strategies, a review of the scientific data on this topic is needed to implement a treatment guide for healthcare professionals.

Methods

A selective literature review was performed via PubMed for articles describing oral surgery / dental implant procedures in patients with congenital and acquired bleeding disorders. Out of the existing literature, potential treatment algorithms were extrapolated.

Results

In order to assess the susceptibility to bleeding, risk stratification can be used for both congenital and acquired coagulation disorders. This risk stratification, together with an appropriate therapeutic pathway, allows for an adequate and individualized therapy for each patient. A central point is the close interdisciplinary cooperation with specialists. In addition to the discontinuation or replacement of existing treatment modalities, local hemostyptic measures are of primary importance. If local measures are not sufficient, systemically administered substances such as desmopressin and blood products have to be used.

Conclusions

Despite the limited evidence, a treatment guide could be developed by means of this narrative review to improve safety for patients and practitioners. Prospective randomized controlled trials are needed to allow the implementation of official evidence-based guidelines.