What is the recommended diagnostic workup and management for suspected von Willebrand disease (VWD)?

Von Willebrand Disease: Diagnostic Workup and Management

Begin diagnostic evaluation with a structured bleeding history using a validated bleeding assessment tool, followed by initial VWD laboratory assays (VWF:Ag, VWF:RCo or VWF:GPIbM, and Factor VIII) if bleeding history is positive, and manage with desmopressin (DDAVP) for minor bleeding/procedures in responsive patients or VWF concentrates for major surgery and non-responders. 1, 2, 3

Clinical Evaluation Algorithm

Initial Screening Questions

For asymptomatic patients before surgery or invasive procedures, ask these three screening questions 1:

• Have you had excessive bleeding from minor wounds or after surgery/dental extractions?
• Do you have a family history of bleeding problems?
• Have you experienced easy bruising, frequent nosebleeds, or heavy menstrual bleeding (in women)?

If ANY answer is positive, proceed to detailed bleeding assessment.

Detailed Bleeding Assessment (9 Key Questions)

When screening is positive or patient presents with bleeding concerns 1:

• Epistaxis requiring medical attention or lasting >10 minutes
• Cutaneous bleeding (easy bruising, petechiae)
• Bleeding from minor wounds lasting >15 minutes or recurring spontaneously within 7 days
• Oral cavity bleeding (gingival bleeding, prolonged bleeding after tooth extraction)
• Gastrointestinal bleeding not explained by anatomic lesions
• Hematuria not explained by infection/stones
• Heavy menstrual bleeding (changing pads hourly, lasting ≥7 days, clots >1cm, flooding, or PBAC score ≥185) 4, 5
• Postpartum hemorrhage requiring intervention
• Muscle hematomas or hemarthroses
• Bleeding requiring transfusion or hospitalization after surgery/trauma

Critical caveat: Check serum ferritin in all women with heavy menstrual bleeding, as iron deficiency is common and affects overall health 4.

Laboratory Diagnostic Workup

Initial Hemostasis Tests 1

Order simultaneously:

• CBC with platelet count
• PTT (may be prolonged if Factor VIII is low)
• PT (typically normal in VWD)
• Initial VWD assays:
  • VWF antigen (VWF:Ag)
  • VWF activity (VWF:RCo or VWF:GPIbM)
  • Factor VIII activity

Do NOT use bleeding time or PFA-100 as routine screening tests - conflicting data on sensitivity/specificity 1.

Interpretation and Further Testing 1, 2

If initial VWD assays are abnormal, proceed to specialized testing:

• VWF:RCo/VWF:Ag ratio (distinguishes type 1 from type 2)
• VWF multimer distribution (identifies type 2A vs 2B vs 2M)
• Ristocetin-induced platelet aggregation (RIPA) (for type 2B)
• VWF:FVIII binding assay (for type 2N)
• Collagen binding assay
• Genetic testing (confirmatory for type 2B, 2N, and type 3; useful for family planning) 2, 6

VWD Classification and Laboratory Cutoffs 1, 5

Type 1 (75% of cases): Partial quantitative deficiency

• VWF:Ag and VWF:RCo both reduced proportionally
• VWF:RCo/VWF:Ag ratio >0.6

Type 2A: Qualitative defect with decreased high molecular weight multimers

• VWF:RCo/VWF:Ag ratio <0.6
• Absent large/intermediate multimers

Type 2B: Increased affinity for platelet GPIb

• Enhanced RIPA at low ristocetin concentrations
• May have thrombocytopenia

Type 2M: Qualitative defect without multimer loss

• VWF:RCo/VWF:Ag ratio <0.6
• Normal multimer pattern

Type 2N: Decreased FVIII binding

• Isolated low Factor VIII with normal VWF levels
• Abnormal VWF:FVIII binding assay

Type 3 (rare, 1:1,000): Virtually complete deficiency

• VWF:Ag and VWF:RCo <3 IU/dL
• Severe bleeding phenotype

Important consideration: VWF levels are influenced by blood type (lower in type O), stress, exercise, pregnancy, estrogens, thyroid hormones, and inflammation. Repeat testing when levels are borderline (30-50 IU/dL) 1, 5.

Management Strategies

For Minor Surgery/Procedures 4, 3

First-line prophylaxis (72% of clinicians use) 4:

• Tranexamic acid (TXA) 1g PO TID starting 1 day before procedure, continue 5-7 days
• Add DDAVP 0.3 mcg/kg IV/SC or 300 mcg intranasal (if patient previously demonstrated response)

DDAVP trial is mandatory before elective procedures to determine individual response 3. Measure VWF:RCo and Factor VIII at baseline, 1 hour, and 4 hours post-dose.

For Major Surgery 4, 3

Prophylaxis approach (59% use TXA, 32% use DDAVP + TXA) 4:

• Target levels: VWF:RCo and Factor VIII >50 IU/dL for major surgery
• DDAVP-responsive patients: DDAVP + TXA
• Non-responders or type 3: VWF/FVIII concentrate
  • Loading dose: 40-60 IU/kg VWF:RCo
  • Maintenance: 20-40 IU/kg every 12-24 hours
  • Duration: Maintain levels >50 IU/dL for 7-10 days post-op

If bleeding occurs despite prophylaxis 4:

• First-line: Add DDAVP (if not already given)
• Second-line: Platelets (37% use), FFP (25% use)
• Third-line: rFVIIa (40% use for major surgery bleeding)

Heavy Menstrual Bleeding Management 4, 3, 7

First-line (standard gynecologic approach):

• Combined oral contraceptive pill (COCP)
• Add TXA 1g PO TID during menses if bleeding persists (57% of clinicians add TXA to COCP) 4

Note: In the United States, there are restrictions on coprescribing TXA with COCP due to theoretical thrombotic risk, though this is commonly done elsewhere 4.

Second-line:

• Levonorgestrel IUD insertion
• DDAVP during menses (if responsive)

Prophylaxis option: For severe cases, regular prophylaxis with VWF/FVIII concentrate 2-3 times weekly reduces heavy menstrual bleeding by 75% 7.

Pregnancy and Delivery 4, 3

Prophylaxis for delivery (58% use TXA, 9% use DDAVP + TXA) 4:

• VWF and Factor VIII levels typically rise during pregnancy
• Measure levels at 34-36 weeks to guide delivery planning
• Target for delivery: VWF:RCo and Factor VIII >50 IU/dL
• Neuraxial anesthesia: Generally safe if levels >50 IU/dL
• Postpartum: VWF levels drop rapidly; maintain prophylaxis for 3-5 days or until bleeding risk resolves

Fetal considerations: Variable practice exists; most clinicians recommend avoiding fetal scalp electrodes and vacuum/forceps delivery in type 3 VWD 4.

Anticoagulation and Antiplatelet Therapy 3

When anticoagulation is indicated (e.g., atrial fibrillation, VTE):

• Anticoagulation is NOT contraindicated in VWD
• Ensure adequate VWF replacement/prophylaxis during high-risk periods
• Consider DOACs over warfarin for easier reversal if bleeding occurs

Antiplatelet agents: Use with caution; avoid in type 2B VWD (risk of thrombocytopenia worsening).

Common Pitfalls to Avoid

1. Misdiagnosis due to variable VWF levels: Always repeat testing if initial results are borderline, especially in type O blood patients 1, 5.

2. Failure to perform DDAVP trial: Never assume DDAVP responsiveness without documented testing 3.

3. Inadequate duration of prophylaxis: Maintain therapeutic levels for full healing period (7-10 days for major surgery) 4, 3.

4. Overlooking acquired von Willebrand syndrome: Consider in patients with new-onset bleeding without family history, especially with lymphoproliferative disorders, aortic stenosis, or hypothyroidism 1.

5. Not checking ferritin in women with heavy menstrual bleeding: Iron deficiency treatment is essential for quality of life 4.

Emerging Therapies 6

Future options under development include:

• VWF aptamers to reduce VWF clearance
• Bioengineered VWF forms
• Gene therapy for type 3 VWD (not yet close to clinical use)