Post-Op Blood Clot Risk High
Study Finds Postoperative Blood Clot Risk Greater, More Persistent Than Experts Thought
WebMD News Archive
Blood Clot Risk After Surgery: Study Results
Compared to the risk of women who didn't have surgery, those who had surgery in the hospital were nearly 70 times more likely to be admitted with blood clots during the first six postoperative weeks. Women who had day surgery (including arthroscopy and minor procedures such as biopsies) were nearly 10 times as likely to have a clot as those who had no surgery.
Overall, one in 140 middle-aged women in the U.K. who have surgery in a hospital would be expected to be admitted with a blood clot during the 12 weeks after the surgery.
The numbers vary by surgery, Green found. ''The riskiest are the major operations -- hip replacement, knee replacement, and other major orthopedic operations, such as operations for hip fractures," Green tells WebMD. Her findings:
• 1 in 45 had clots after hip or knee replacement
• 1 in 85 after cancer surgery
• 1 in 815 after day surgery
• 1 in 6,200 women who did not have surgery
Lack of movement is mostly to blame, Green says. "Your legs are immobile, and you don’t have the normal mechanism where muscles are helping blood flow. Some anesthetics increase the risk even further by causing veins in the leg to dilate, so there is more pooling of blood."
Cancer itself may also trigger blood changes that boost blood clot risk, she says.
The study results, Green says, may inspire doctors and policy makers to extend the typical time that preventive measures such as anticoagulants and compression stockings are used. Those times vary, with some ending at hospital discharge and others continuing for up to four weeks, she writes.
Blood Clot Risk Post-Op: Other Opinions
The study is an important one, says James Muntz, MD, clinical professor of medicine at Baylor College of Medicine in Houston. Muntz, an internist, recently published a paper advocating extended-duration therapy to prevent clots after orthopedic surgery. He says he isn't sure the new findings will inspire an immediate change in guidelines for preventing clots. "I think it will at least trigger a change in people's awareness,'' he says. And prolonged preventive measures would be expected to be as good for men as for women, he says.