Haemostatic changes following surgery.

Changes in factors V, VII and VIII and in fibrinogen were studied in 32 patients undergoing major abdominal surgery. Mean levels of factors V and VII were similar to population-based values preoperatively. Factor V fell following elective surgery and then rose above the mean pre-operative level before returning to it by the tenth post-operative day. Factor VII fell following both elective and emergency surgery and tended to remain depressed throughout the post-operative period. Pre-operative values of factor VIII and fibrinogen were higher than population-based values and higher in the emergency than in waiting-list patients. Both factor VIII and fibrinogen rose following elective surgery but no statistically significant change was seen following emergency surgery. The uncomplicated conditions leading to elective surgery, the acute complications leading to emergency surgery, and surgery itself may each have contributed to increases in factor VIII and fibrinogen levels, whereas the fall in factors V and VII was largely related to surgery itself. The findings may help in the interpretation of associations between clotting factors and thrombotic disease, particularly in the case of factor VII.