Perioperative substitution therapy in patients with vWD must be tailored
Even in cases of von Willebrand disease (vWD), available data supports the need for individualized approaches in ensuring surgical procedures to prevent FVIII accumulation and high factor consumption.
Goals of perioperative care in patients with vWD
Patients with von Willebrand disease receive concentrates containing von Willebrand factor (vWF) in cases of acute bleeding, trauma, or surgical intervention. The goal is to dose the concentrates effectively and safely. A study was conducted in the Netherlands to evaluate the perioperative regimen of vWD patients in terms of target vWF and factor VIII (FVIII) levels as set in national guidelines.
Methodology and course of the study
The multicenter study monitored patients with vWD who underwent minor or major surgeries between 2000 and 2015 and received vWF and FVIII concentrates, specifically Haemate P. The activity of vWF and FVIII was assessed during the dosing regimen, which was guided by measured FVIII levels.
The measured levels were compared to predefined target levels according to national guidelines. These guidelines recommend an initial dose of 50 IU/kg body weight of vWF/FVIII concentrate (30–50 IU/kg for minor surgeries). Maintenance doses should range from 15–25 IU/kg twice daily, and achieved levels should be regularly monitored as judged by the physician. The target trough level for both vWF activity and FVIII concentration is defined as > 0.8 IU/ml in the first 36 hours post-surgery; subsequently, FVIII trough concentration should reach > 0.5 IU/ml.
Results
A total of 103 patients who underwent 148 surgeries were monitored. Among them, 54 had type 1 vWD (73 surgeries), 43 had type 2 (67 surgeries), and 6 had type 3 (8 surgeries).
Overall, the treatment led to high levels of vWF and FVIII activity (i.e., > 0.2 IU/ml above the predefined activities). For type 1 vWD patients, the minimum vWF activity level was higher than the target level in 65% of cases, and FVIII levels in 91% of surgeries. For type 2 vWD patients, the proportion of higher-than-target levels was 53% for vWF activity and 72% for FVIII, and for type 3, 57% for vWF activity and 73% for FVIII.
Additionally, a cumulative increase in FVIII levels was observed over time, while vWF activity tended to decrease, resulting in significantly higher FVIII levels compared to vWF activity.
Conclusion
The authors state that the study results confirm the trend of increasing FVIII with signs of its accumulation, and generally higher than targeted levels of vWF. Therefore, it is highly desirable to emphasize the personalization of dosing schemes in vWD patients for perioperative care.
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Source: Hazendonk H. C. A. M., Heijdra J. M., de Jager N. C. B. et al. Analysis of current perioperative management with Haemate P®/Humate P® in von Willebrand disease: identifying the need for personalized treatment.Haemophilia 2018; 24 (3): 460–470, doi: 10.1111/hae.13451.
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