▪ The surgical procedure should be absolutely indicated.

▪ The type and site of surgery will determine what treatment is necessary.

▪ A good bleeding history should be taken to establish potential bleeding risk.

▪ Full cardiovascular review is necessary to determine risks of fluid overload with fresh frozen plasma (FFP) and thrombotic risk associated with factor XI (FXI) concentrate.

▪ Other coagulation tests and platelet count should be normal.

▪ An FXI inhibitor should be excluded, particularly in patients with a baseline FXIC <1 IU/dL.

▪ Antiplatelet agents including aspirin and other non-steroidal anti-inflammatory agents should be discontinued at least 7 days before surgery.

▪ For patients with severe deficiency undergoing major surgery the trough FXIC level should be kept above 45 IU/dL for about 10 days. Regular FXIC level monitoring is essential.