What is the recommended management for a patient with von Willebrand disease and a von Willebrand antigen activity ratio of 0.7 to prevent bleeding complications during surgery?

Management of Von Willebrand Disease with VWF:Ag/Activity Ratio of 0.7 for Surgical Procedures

For patients with von Willebrand disease and a VWF:Ag/activity ratio of 0.7, desmopressin (0.3 μg/kg) is the first-line treatment to prevent bleeding complications during surgery, as this ratio indicates a mild qualitative defect consistent with type 2 VWD. 1, 2

Diagnosis Confirmation

A VWF:Ag/activity ratio of 0.7 is at the critical diagnostic threshold for qualitative VWF defects, suggesting:

• Possible type 2 VWD (particularly since the patient's mother has the same ratio)
• Loss of high-molecular-weight VWF multimers which significantly increases bleeding risk during surgery 2

Additional testing should include:

• VWF multimer analysis to confirm the specific subtype
• Factor VIII coagulant activity level
• VWF ristocetin cofactor activity (VWF:RCo) 1

Pre-Surgical Management Algorithm

1. Confirm Factor VIII levels >5%

   • If <5%, VWF concentrate is required instead of desmopressin 3

2. Determine VWD subtype

   • Critical to differentiate type 2A from 2B as desmopressin is contraindicated in type 2B (can worsen thrombocytopenia) 2

3. Pre-surgical desmopressin trial

   • Administer test dose (0.3 μg/kg diluted in 50 ml saline over 30 minutes)
   • Measure response (VWF:RCo, FVIII levels) at 1 hour and 4 hours post-administration 1
   • Adequate response: VWF:RCo and FVIII levels >50 IU/dL for minor procedures, >100 IU/dL for major surgery 2

Surgical Management Plan

For Responsive Patients:

1. Administer desmopressin 0.3 μg/kg 1 hour before procedure 1
2. Restrict free water intake to prevent hyponatremia 3
3. Monitor serum sodium within 24 hours and periodically during treatment 3
4. Consider repeat doses every 12-24 hours if needed (maximum 3 consecutive days due to tachyphylaxis) 2

For Non-Responsive or Type 2B Patients:

1. Administer VWF concentrate to achieve target levels:

   • 50 IU/dL for minor procedures

   • 100 IU/dL for major surgery 2

2. Use plasma-derived concentrates containing both FVIII and VWF 2

Adjunctive Treatments:

1. Tranexamic acid (antifibrinolytic agent) for mucosal bleeding control 2
2. Consider platelet concentrates if bleeding continues despite adequate VWF levels 4

Post-Surgical Monitoring

1. Laboratory monitoring:

   • VWF:RCo levels
   • Factor VIII activity
   • Platelet count (especially if type 2B suspected)
   • Serum sodium 2, 3

2. Clinical monitoring:

   • Surgical site bleeding
   • Mucosal bleeding
   • Drain output
   • Hemoglobin levels 2

3. Duration of treatment:

   • Continue monitoring for 7-14 days post-operatively depending on procedure 2
   • Be vigilant for delayed hemorrhage 5

Important Caveats

• Risk of hyponatremia: Desmopressin can cause severe hyponatremia; restrict fluid intake and monitor sodium levels 3
• Tachyphylaxis: Effectiveness decreases with repeated doses over consecutive days 2
• Delayed bleeding: Patients with VWD may experience delayed postpartum or post-surgical hemorrhage despite adequate prophylaxis 5
• Bleeding risk: Patients with VWF:Activity/Antigen ratio <0.7 experience bleeding at sheath insertion sites (100%) and massive bleeding (40%) 2

Special Considerations

• Pregnancy: VWF levels should be maintained >50 IU/dL during pregnancy and >100 IU/dL during delivery 2
• Age: More frequent monitoring of serum sodium in patients ≥65 years 3
• Concomitant medications: Avoid loop diuretics and systemic/inhaled glucocorticoids during desmopressin treatment 3

By following this algorithm, surgical bleeding complications can be minimized in patients with von Willebrand disease and a VWF:Ag/activity ratio of 0.7.