New Anesthesia Procedure Reduces Cardiac Complications In Surgery Patients, UB Researchers Report

By Lois Baker

Release Date: December 13, 1993 This content is archived.


BUFFALO, N.Y. -- Changing the type and method of administering anesthesia and pain killers to high-risk surgery patients can dramatically reduce the risk of postoperative cardiac abnormalities, and possibly lessen the chance of heart attack, University at Buffalo researchers have found.

A team of anesthesiologists lead by Oscar de Leon-Casasola, M.D., UB assistant professor of anesthesiology, followed the surgery and early recovery of 198 patients admitted during one year to Roswell Park Cancer Institute for upper abdominal cancer surgery.

One group of 88 patients received standard general anesthesia during surgery, and morphine for pain after surgery, self-administered through an intravenous line.

Another group of 110 patients received combined anesthesia therapy using bupivacaine and morphine via epidural -- a direct line into the space surrounding the spinal cord that deadens a localized area. After the operation, the same two drugs, adjusted for pain control, continued to be administered by epidural.

All patients had an electrocardiogram every 12 hours for three days following surgery to detect cardiac abnormalities.

Results showed that patients in the epidural group had 51 percent fewer incidents of tachycardia, or rapid heart beat, 12 percent fewer episodes of ischemia -- a shortage of blood to the heart -- and suffered no heart attacks.

Surgery-related heart problems are frequent, life-threatening complications of major surgery. Forty percent of high-risk patients suffer ischemia, de Leon-Casasola said, and 8 to 20 percent suffer a myocardial infarction, or heart attack, after surgery.

When surgeons at Roswell Park Cancer Institute in Buffalo reported a significant drop in heart attacks following major cancer surgeries, the team of anesthesiologists began an investigation into the cause of the decrease.

"We had been using combination therapy for about five years," said de Leon-Casasola, "and there was much data suggesting that patients receiving a combination of anesthesia agents via epidural have better outcomes. So we decided to take a look at that issue."

A comparison of the number of cardiac incidents within the two groups showed 15 episodes of tachycardia in patients who received epidurals versus 58 who received general anesthesia, and five ischemia episodes with epidural versus 15 with general. Three patients in the general group suffered heart attacks, but there were no deaths.

The two groups were similar in age, sex, the number of cardiac risk factors, the number taking anti-angina drugs, preoperative heart rate and incidence of ischemia before and during surgery.

The favorable results led the researchers to theorize that the epidural anesthesia dilates the coronary blood vessels, helping to prevent ischemia. They also speculate that adding morphine to the anesthesia mix improves pain control, which prevents the nervous system from releasing certain compounds that can cause blood vessels to constrict in persons with coronary artery disease.

"The fact that all ischemic episodes in the epidural group were associated with tachycardia, and not blood-vessel constriction, suggests we might be protecting the hearts of these patients by blunting this effect," said de Leon-Casasola.

The results were presented at the annual meeting of the American Society of Regional Anesthesia and reported in the September issue of Anesthesiology News.

The researchers currently are preparing a larger study to see if they can duplicate the results.

In addition to de Leon-Casasola, members of the team are Dora Karabella, M.D.; Patricia Harrison, M.D., and Mark Lema, M.D., Ph.D., all of UB and Roswell Park.