Low-dose intermittent factor replacement for post-operative haemostasis in haemophilia

Recommendations for factor replacement therapy for postoperative haemostasis in haemophilia are often empirical and based on the physiological understanding of haemostatic requirements. This report describes the haemostatic management of patients with severe haemophilia undergoing major surgery using lower than usually recommended levels of factor replacement therapy. Eighteen adults (11 with FVIII and seven with FIX deficiency) with an average weight of 52 kg (range: 27-69) underwent 20 major surgical procedures. Factor concentrates were administered by intermittent bolus infusions. The dose of FVIII infused before surgery was 76 u kg^-1 (range: 51-113) and that of FIX was 77 u kg^-1 (range: 50-104). The preoperative levels achieved were 107% (range: 80-180)and 73% (range: 60-90), respectively. Between days 1 and 3 after surgery, an average of 29 u kg^-1 day^-1 (range: 20-46) of FVIII and 23 u kg^-1 day^-1 (range: 12-42) of FIX was used resulting in mean trough levels of 36% (range: 12-62) and 34% (range: 11-52), respectively. After day 4, an average of 19 u kg^-1 day^-1 (range: 15-25) of FVIII and 18 u kg^-1 day^-1 (range: 10-37) of FIX was administered until wound healing. The average duration of factor replacement was 11 days (range: 8-16). The mean dose of factor concentrate per patient was 260 u kg^-1 (range: 179-338) of FVIII and 300 u kg^-1 (range: 183-524) of FIX. The total amount of factor used per patient ranged from 12,380 to 19,980 units of FVIII and 8000 to 23,600 units of FIX. Only one patient had post-operative bleeding which was due to a surgical cause. It is concluded that it may be possible to use much lower than recommended levels of factor replacement therapy for postoperative haemostasis in severe haemophilia.