I believe it is a setteled issue regarding long term memory loss due to a by-pass. There has been a study and 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 decline."
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
SOURCES: 134th Annual Meeting of the American Neurological Association, Baltimore, Oct. 11-14, 2009.
Ola A. Selnes, PhD, department of neuropsychology, Johns Hopkins School of Medicine, Baltimore.
Craig Blackstone, MD, PhD, National Institute of Neurological Disorders and Stroke.
A study involved about 150 heart patients who underwent bypass surgery, 150 heart patients who took medication, and 69 people with no known risk factors for heart disease.
"As expected, people who were older and had less education experienced faster cognitive decline," Selnes says. Having plaque buildup in all three of the main heart arteries and a history of irregular heartbeats known as atrial fibrillation also predicted faster memory loss and mental decline.
But people with coronary artery disease at greatest risk of mental decline were those with a combination of risk factors, including high blood pressure, a past stroke, and diabetes, the study showed
Two Johns Hopkins researchers who have been at the forefront of this field reviewed the evidence on short-term and long-term mental changes after bypass surgery. They found that short-term confusion, memory loss, and poorer problem solving and information processing are common after bypass surgery, but are usually temporary and reversible. Most people return to their pre-bypass level of function between 3 and 12 weeks after surgery.
Long-term changes occur, too, but these are usually mild and tend to affect things such as how fast you can solve problems or process information. The authors suggest that these changes probably arise from changes in the brain caused by atherosclerosis. They also acknowledge that it isn’t possible right now to determine whether these changes are caused by bypass surgery, normal aging, the slow development of Alzheimer’s disease, the mini-strokes of vascular dementia, or other causes.
Hope this helps provide a perspective. A current on-going test for the issue of interest doesn't appear to be happening. Also, the studies for long term effects take years to establish a link, and what studies that have been given may now begin to show any long-term effects. and it appears the jury is still out on the subject.
Thanks for the questions, and if you have any further questions or comments you are welcome to respond. Take care.