PB1144 - Outcomes with Perioperative Factor Utilization and Monitoring Strategies in Hemophilia A

Background: Factor activity levels are commonly monitored in the post-operative setting for persons with hemophilia (PWH). The clinical relevance of this remains unexplored and it is unknown how often the levels effect changes to factor dosing.

Aims: To describe real-world experience of modern perioperative management in hemophilia A and observe the clinical relevance of factor level monitoring.

Methods: We conducted a retrospective observational study of surgical procedures of adults (age >18) living with hemophilia A performed at our institution from January 2015 to July 2021. Data collected includes patient demographics, factor administration strategy, dose adjustments and outcomes. Factor levels were also captured and defined as therapeutic if >60 IU/dL on post-operative days 1-3. Major bleeding was defined according to the standard ISTH definition.

Results: Eighty surgical procedures were identified (44 on patients with severe hemophilia, 34 with mild and 2 with moderate disease). There were 9 patients on active emicizumab therapy and 4 patients with inhibitor. Thirty-eight (47.5%) cases utilized a continuous factor infusion. The drip rate was decreased in 15 (39.5%) cases and increased in 3 (7.9%). The starting infusion rates for the latter were < 4 units/kg. None had subtherapeutic factor levels or major bleeding. Of patients who underwent bolus dosing only (52.5%), the dose was decreased in 3 cases (7.1%) and increased in 2 (4.8%). In total, 13 (16.3%) hospitalizations had subtherapeutic factor levels in the post-operative setting. Complications were rare. Four cases had major bleeding (three intraoperative), no patients required packed red blood cell transfusion and there were no thrombotic complications.

Conclusion(s): For PWH undergoing surgery, factor monitoring was more likely to lead to a decrease in rate of continuous infusions rather than an increase. Subtherapeutic factor levels resulting in the increase in factor dosing is uncommon and with minimal clinical consequence.