No Link Between Bypass Surgery, Memory Loss
Underlying Heart Disease, Not Surgery, Linked to Subtle Mental Decline
Oct.14, 2009 (Baltimore) -- Despite reports to the contrary, having bypass
surgery to help your heart does not harm your brain, researchers report.
In a new study, no support was found for a link between
heart bypass surgery and memory loss or other mental declines. The
underlying heart disease that led patients to have heart bypass surgery was
associated with memory loss, however.
"The good news is that the cognitive decline is very subtle, so subtle that
people thought the changes were part of [the memory loss that accompanies]
normal aging,” says Johns Hopkins School of Medicine neuropsychologist Ola A.
The findings were presented at the annual meeting of the American
Neurological Association (ANA).
Heart Bypass Surgery
Heart bypass surgery involves rerouting blood around clogged
arteries to improve the supply of blood and oxygen to the heart.
Researchers from Duke University first raised concerns about the long-term
impact of the surgery on memory and mental function in a highly publicized
study eight years ago. The researchers reported that more than a third of
patients with coronary artery disease still had measurable mental decline five
years after having heart bypass surgery.
But the Duke researchers did not compare the bypass patients to people with
coronary artery disease who underwent treatments other than bypass surgery or
to healthy adults with no heart disease, Selnes says. So it was not clear if
the mental declines were caused by the heart bypass surgery, the heart disease that
prompted the surgery, or by natural aging.
The new study involved 69 heart-healthy people and 326 people with coronary
artery disease. Coronary artery disease is usually caused by the buildup of
plaque on the inside of the coronary arteries, the blood vessels that supply
oxygen-rich blood to the heart muscle.
Of the 326, about half had bypass surgery, one-fourth took medications, and
the rest underwent off-pump surgery in which the surgeon operates on the
beating heart. “It’s a very demanding operation,” Selnes says.
Plaque Buildup Probably Cause of Mental Decline
During four checks over the next four years, there were no significant
differences in memory or other mental functions between the heart patients who
had bypass, those who took medications, and those who had off-pump surgery.
At four years, however, all three groups of heart patients scored
significantly worse on tests of memory, decision-making, and visuospatial
relations than the heart-healthy people.
“What matters is whether you have coronary artery disease, not what
treatment you receive,” Selnes tells WebMD. “If your doctor recommends bypass
surgery, you shouldn’t avoid it because of concerns about cognitive
Craig Blackstone, MD, PhD, a researcher at the National Institute of
Neurological Disorders and Stroke who is on the ANA’s executive council, says
the findings make sense.
People who have plaque buildup in the vessels leading to the heart probably
have plaque buildup in the arteries leading to the brain that can lead to
cognitive decline, he says.