Surgical patients are as much as 70 times more likely to be hospitalized for a blood clot than non-surgical patients, according to a new study that suggests the risk of post-surgical venous thromboembolism (VTE) is higher than previously thought.

A review of data from the U.K. Million Women Study published in the journal BMJ shows inpatient surgery increases the risk of deep vein thrombosis and pulmonary embolism by about 70 times in the first 6 weeks after the procedure, while outpatient surgery raises the risk about 10 times. The risk diminishes after 7 to 12 weeks but is "still substantially increased" compared to those who do not undergo surgery. Inpatient hip and knee replacement and cancer surgeries pose the greatest risk of post-surgical VTE, researchers found.

The findings were based on data from nearly 1 million middle-aged women in the United Kingdom. Members of the study group were at a relatively low risk of venous thromboembolism and underwent a single surgical procedure, 60% of which were day surgeries. Characterizing the findings as "a wake-up call to all surgeons," vascular surgeon Alexander T. Cohen, MD, of King's College Hospital in London stresses the importance of assessing the risk of VTE and taking steps to prevent it in surgical patients in order "to improve safety, prevent morbidity and mortality, and save money."

Irene Tsikitas