The following figures emerge from this Anesthesiology review: Annual rates of major hemorrhagic events ranged from 1.0 to 7.4% in a systematic review of patients with atrial fibrillation receiving vitamin K antagonist therapy, while rates of intracranial hemorrhage in the same population ranged from 0.1 to 2.5%. Major bleeding occurred in 3.3% of warfarin-treated patients undergoing elective surgery, but 21.6% in patients in emergency surgery
Fresh Frozen Plasma brings risks of fluid overload, lung injury, infection and is slow to act and less effective. Vitamin K alone is feasible only when surgery can be delayed 24-48 hours.
Current guidelines recommend prothrombin complex concentrates (PCC), specifically four-factor prothrombin complex concentrates, with concomitant intravenous vitamin K, as the preferred therapy for urgent vitamin K antagonist reversal, which are effective in 30 minutes or so. PCCs reduces bleeding and some studies suggest mortality also. Many studies show them to be more effective than FVIIa. Thromboembolism has not been found to be increased to date.
Whereas specific reversal agents are in use or being introduced for Factor Xa Inhibitors and Direct Thrombin Inhibitors, PCCs may be worth considering for hemorrhage in such patients in the interim although their efficacy is very variable for non-vitamin K antagonist reversal.
The full review surveys all the published studies and also examines evidence in various scenarios such as intracranial hemorrhage, cardiac surgery and trauma.