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 continued...
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
• 1 in 45 had clots after
hip or knee replacement
• 1 in 85 after cancer
• 1 in 815 after day
• 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
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
Another physician in practice, Charles F. Chandler, agrees. ''The study is
important because it raises an index of suspicion that this phenomenon can
occur after relatively minor procedures and for a long period of time."
Chandler is a general surgeon at Santa Monica-UCLA Medical Center and
Orthopaedic Hospital and a clinical professor of surgery at the University of
California Los Angeles David Geffen School of Medicine. One limitation of the
study, also pointed out by the authors, is that no information was available on
whether the women took preventive measures to avoid clots, he says.
Blood Clot Risks: What Can Patients Do?
Surgeons routinely caution their patients to be aware of potential symptoms
of blood clots, Green says. Her advice to surgery patients in the wake of her
new findings? "To repeat what they will have been told by their surgeon -- the
message than an unexplained pain in the calf, or swelling, can be a sign, and
not to dismiss it, even if it's several months after the surgery.''
Chandler tells his surgery patients: "Treat it like an injury" and give the
body time to heal. ''We want patients to be proactive," he says. "Ask your
surgeon: 'What is my risk of a blood clot?'"