high blood sugar and surgery

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High Blood Sugar Increases Risk of Blood Clots After Surgery

By Rick Ansorge

HealthDay Reporter

MONDAY, Oct. 16 (HealthDay News) -- Patients, such as diabetics, who have high

blood-sugar levels before undergoing hip- or knee-replacement surgery are

at increased risk of developing potentially life-threatening blood clots,

according to a new study.

" The take-home message is that all patients should get their blood sugar under

control before undergoing elective surgery, " said the study's lead author,

Dr. Boris Mraovic, an assistant professor of anesthesiology at Jefferson

University in Philadelphia.

Mraovic's team examined records of 6,500 patients who underwent hip- or

knee-replacement surgery at Jefferson University Hospital between 2003

and

2005. They identified 38 patients who had blood-glucose levels above 250

milligrams per deciliter during pre-operative testing and on the day of surgery.

All but one of the patients were diabetic, which is defined as a fasting

blood-glucose level above 126 mg/dl.

" We found that 10.5 percent of those with high blood sugar developed a pulmonary

embolism compared to only 1.7 percent of the other patients, " Mraovic said.

" This rate is more than six times higher than we would expect to see in the

general population. "

Pulmonary embolism is a potentially life-threatening condition in which a blood

clot forms in a vein and travels to the lungs. It's usually caused by clots

that form in veins deep in the muscles of the legs or pelvic area, a condition

known as deep-vein thrombosis.

Pulmonary embolism is more likely to develop after major orthopedic surgery than

after other types of surgery. Nationwide, about 600,000 patients develop

a pulmonary embolism each year and 200,000 of them die.

" Fortunately, none of the 38 patients in our study died, " Mraovic said. " We

treat pulmonary embolism aggressively. "

Mraovic was expected to present his study findings Monday at the annual meeting

of the American Society of Anesthesiologists, in Chicago.

" This is a fascinating study, " said Dr. Goldhaber, a cardiologist at

Brigham and Women's Hospital in Boston, who was not part of the study. " I'm

not aware of previous studies linking poor

glucose

control with pulmonary embolism in patients undergoing surgery. So, this is the

first one. "

Although Goldhaber called the new research " intriguing and thought-provoking, "

he cautioned that it's premature to draw any major conclusions from it.

" This is just one exploratory study, " he said. " It should prompt researchers to

look through other databases to see if there's a similar relationship between

high blood glucose levels and pulmonary embolism. "

Previously, researchers didn't know if high blood sugar, per se, was an

independent risk factor for pulmonary embolism in patients who undergo major

orthopedic

surgery. In fact, some research suggested otherwise. In 2002, a Mayo Clinic

study of 19,293 such patients found that type 2

diabetes

was not an independent risk factor for either deep-vein thrombosis or pulmonary

embolism.

" The problem is, that study didn't examine high blood sugar, " Mraovic said. " If

you're diabetic, you can have normal blood sugar if you are taking medication. "

Recent evidence shows that tight blood-sugar control leads to better results in

patients who undergo cardiovascular surgery, Mraovic said. It's associated

with improved survival, fewer infections, shorter hospital stays and lower

costs.

Mraovic said guidelines are needed to limit elective surgery in patients who

have high blood sugar. He favors guidelines that would require the postponement

of such surgery until patients get their blood sugar under control. " At present,

there are no such guidelines from surgical or anesthesia associations, "

he said.

Goldhaber disagreed. " I think more trials and studies are needed before we go

that route, " he said.

But he didn't dispute that well-controlled blood sugar should be the " rule of

thumb " for all surgical patients, especially now that so many of them are

diabetic. " Diabetes is becoming pandemic as part of the

metabolic syndrome, "

Goldhaber said. " We need to focus a lot more attention on tightening blood-sugar

control. "

Mraovic said that additional studies are needed to confirm his results. He hopes

to perform a prospective, randomized study of patients with high blood

sugar to see if controlling their blood sugar before surgery lowers the risk of

deep-vein thrombosis and pulmonary embolism.

SOURCES: Boris Mraovic, M.D., Artificial Pancreas Center at Jefferson Medical

College, Jefferson University, Philadelphia; Goldhaber, M.D.,

Cardiovascular Division, Brigham and Women's Hospital, Boston; Oct. 16, 2006,

presentation, annual meeting of the American Society of Anesthesiologists,

Chicago