NEW YORK (Reuters) -- The occurrence of stroke and other brain-related complications of coronary artery bypass surgery still remain all too common, researchers say, and may become even more so as the population ages.
The new study links these "adverse cerebral outcomes" to "substantial increases" in death, hospitalization, and long-term nursing home care.
"In patients who have coronary bypass surgery, 3.1% will have stroke and another 3% will have a serious neurologic injury, or an encephalopathy -- confusion and agitation -- for a prolonged period," says study lead-author Dr. Gary Roach, a cardiovascular anesthesiologist at Kaiser-Permanente Medical Center, San Francisco.
"We found that both of these types of outcomes have significant impact on mortality (death), with strokes increasing mortality by a factor of 10 and more than five-fold for encephalopathy," he says.
The study followed more than 2,000 bypass surgery patients at 24 medical centers over a two-year period.
Roach and his colleagues identified a number of factors that increased the likelihood of adverse brain outcomes.
The most significant factor for stroke was atherosclerosis, or fatty deposits, in the aorta -- the body's main artery.
"This factor is most likely significant for stroke because of the surgical procedure itself, which involves manipulating the aorta," Roach explains. "Then, (fatty) particles break off and go the brain, which can cause stroke."
Other significant stroke factors include increasing age (particularly greater than 70 years), previous history of stroke, and diabetes. Factors increasing the likelihood of other neurological complications are older age, excessive alcohol consumption, high systolic blood pressure (when the heart actively pumps), and lung disease.
As to what the new findings tell us, Roach is clear: "Despite the popularity of the (coronary bypass) procedure, we have not made any progress on either decreasing neurologic and brain injury or being able to treat it when it does occur," he says.
The researcher also points out, "Only about one third of patients with stroke are able to go home from the hospital. (Many) have to go to a long-term facility."
Roach says the findings should more effectively allow doctors to communicate the risks of coronary bypass surgery to their patients.
"And for patients who are at high risk, we may be able to alter certain aspects of the operation that may decrease a neurological injury -- primarily, manipulation of the aorta," says Roach.
"We may be able to identify some of these patients pre-operatively who have prohibitive risk. And there are some anti-stroke medications which are being tested now that may have some application," the researcher adds.
SOURCE: The New England Journal of Medicine (1996;335:1857-1863)
