Bypass Surgery May Not Affect Brain Function

A broad retrospective review of the effects of coronary bypass surgery on memory and other brain functions has shown that while there may be transient short-term effects, the procedure probably does not cause late or permanent neurologic defects.

The researchers found that the late cognitive declines seen in some long-term studies are likely associated with the progression of underlying conditions, such as cerebrovascular disease, rather than the surgery itself. The exceptions might include older patients and those with risk factors for cerebrovascular disease or a history of stroke.

Existing studies confirm the existence of mild deficits in the period up to three months after surgery, which may be due to minor disruption in blood flow or other surgery-related factors, such as inflammation or anesthesia. When the researchers examined the most authoritative studies, they failed to find strong evidence that cognitive deficits persist after three months in most patients.

"We think that there are short-term cognitive changes after coronary artery bypass grafting (CABG) in a subset of patients, but absent a frank stroke, these changes are generally mild and transient,” said author Ola Seines, Ph.D., professor of neurology at Johns Hopkins Hospital (Baltimore, MD, USA).

One possible cause of the cognitive defects found in studies, say the authors, may be the fact that the population having bypass surgery is becoming older and sicker, with more hypertension, diabetes, previous strokes, and other disorders.

"We believe that patients should not be discouraged from having CABG because of the risk of late cognitive function,” added Dr. Seines.




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