A new study says that the risk of developing potentially fatal blood clot following a surgery is higher than previously believed and it lasts for a longer period.
The risk of venous thromboembolism (a collective term for deep vein thrombosis and pulmonary embolism) is known to increase after surgery, particularly after major orthopaedic (joint) surgery.
The new study holds significance as most patients receive preventive (anti-clotting) therapy only whilst in hospital, or for up to five weeks after certain high-risk operations.
And those undergoing day surgery are unlikely to be considered for preventive therapy at all.
An international team of researchers set out to examine the pattern of increased risk of venous thromboembolism over time and after different types of surgery.
The study revealed that compared to the risk without surgery, women were almost 70 times more likely to be admitted with venous thromboembolism during the first six weeks after an inpatient operation and almost 10 times more likely after a day case operation.
The risks were lower but still elevated 7-12 weeks after surgery, and in most cases the risk remained for at least one year, reports the British Medical Journal.
The risk also varied considerably by type of surgery, being highest after inpatient surgery for hip or knee replacement, cancer and fracture.
In real terms, this means that 1 in 140 middle aged women is likely to be admitted to hospital with venous thromboembolism during the 12 weeks after any inpatient surgery, 1 in 45 after hip or knee replacement surgery, and 1 in 85 after surgery for cancer
These findings suggest substantially increased risk of venous thromboembolism after many different types of surgery that lasts for up to 12 weeks postoperatively, conclude the authors.