WFU Baptist Medical Center Researchers Work to Reduce Complications of Bypass Surgery

February 26, 1999

With a new $1.9 million federal grant, Wake Forest University Baptist Medical Center will expand research on how hospitals can reduce the number of patients who experience confusion, memory loss and personality changes after heart bypass surgery. The Medical Center - among the first in the world to explore this problem - has already reduced its rates of neurologic injury to 70 percent below the national average.

As bypass surgery has become safer - and the risk of mortality has decreased - research has focused on other complications of the surgery. The goal is to reduce occurrences of brain injury, which can range from minor changes that aren''t noticed by the patient to major strokes and disability.

By making small adjustments in surgery techniques, the Medical Center reduced the number of patients having major strokes during bypass surgery to 1 percent, well below the national average of 6 percent. It reduced the number of patients experiencing less severe injury to 18 percent - 70 percent below the national average.

"The changes we''ve made have dramatically affected neurological outcomes of our patients," said John W. Hammon, Jr., M.D., professor of cardiothoracic surgery and principal investigator for the research. "With the grant from the National Institute of Neurological Disorders and Stroke we hope to duplicate our results in a larger group of patients. Our ultimate goal is to make a safe operation even safer."

The Medical Center will collaborate with the Department of Surgery at University Health Systems of Eastern Carolina in Greenville to evaluate the modifications in 300 patients. All patients will be tested before and after surgery to measure concentration, memory, vocabulary, hand-eye coordination and other areas that can be affected during bypass surgery.

Nationwide, about 60 percent of patients have tiny strokes during bypass surgery that result in neurological changes. The changes are sometimes so minor they aren''t noticed by the

patient, and can be detected only through testing. Other patients, however, report permanent difficulty remembering names, balancing a checkbook and performing tasks requiring motor skills, such as typing.

"The way the dysfunction affects your life depends on who you are and what you do," said David Stump, Ph.D., research associate professor of anesthesiology and neurology, who is part of the research team. "If you''re a professional golfer and you have a change in motor function, your career could be over. But if the change is in language function, your golf game wouldn''t be affected."

Medical Center researchers were among the first in the world to explore why some patients having bypass surgery have strokes and neurological changes. They identified the cause as tiny particles of plaque, air bubbles and blood clots - known together as emboli - that travel to the brain during surgery and block vessels. The plaque can break off the sides of the heart''s vessels when the heart is moved during surgery.

With an earlier grant from the National Institutes of Health, the researchers developed an ultrasound probe to monitor emboli as they flowed through the major vessel that carries blood to the brain. They learned that making minor changes in surgical technique dramatically reduced the number of emboli going to the brain, which resulted in fewer patients having major strokes or permanent neurological changes.

The surgical changes include not using clamps on the body''s main artery, moving the heart less during surgery, and using ultrasound to locate and avoid heavy concentrations of plaque in the arteries. The $1.9 million grant will allow the research team to explore additional ways to avoid brain injury, such as finding the best rate for "re-warming" the brain after surgery. The blood is cooled by the heart-lung machine during surgery and physicians have found that the cooler brain is less susceptible to injury from emboli. They hope that finding the best rate for re-warming will provide an additional way to avoid brain injury.


Media Contacts: Karen Richardson, (336) 716-4453 or Jim Steele, (336) 716-3487. This release is available electronically at

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