For 15 years David Rasmussen, 72, a retired airline dispatcher living in Clarksville, Va., had solved at least one crossword puzzle a day. But for a while after he underwent double-bypass surgery at Duke University Medical Center last October, Rasmussen hardly glanced at his beloved crosswords. "I found it hard to concentrate," Rasmussen recalls. "All I wanted to do was sit around and watch television."
You could hardly blame him. After all, Rasmussen had had his chest cracked open, his heart stitched up and was swimming in painkillers. Is it any wonder that he--and 30% to 80% of the more than 500,000 Americans who undergo bypass each year--would experience bouts of mental fogginess after surgery? Most surgeons assumed these effects were temporary, since they usually disappeared a few weeks or months after the operation--as they did in Rasmussen's case. Besides, doctors tended to focus on the more pressing bypass complications--stroke, for example, which occurs in 1% to 5% of cases and can lead to permanent disability or death.
But there has always been a nagging suspicion that the subtle changes in personality and lapses in mental acuity that are sometimes seen after bypass surgery might be the result of brain damage caused by the operation itself. That's why there was so much interest last week in a study published in the New England Journal of Medicine that found 42% of bypass patients still experienced cognitive decline five years later.
The study, conducted by Dr. Mark Newman and colleagues at Duke University Medical Center, tracked 261 patients and periodically gave them standardized tests of cognitive function. Many recovered fully in the weeks after surgery, but about a third did not. In general, patients who were older, less well educated or who had previously experienced mental confusion in the aftermath of the surgery appeared to be at greatest risk of a long-term decline. (Vice President Dick Cheney was 47 when he underwent quadruple-bypass surgery in 1988.) What surprised Newman's team most, however, was that the rate of impairment, after falling to 24% in the first six months, subsequently rose, suggesting that the apparent damage in many cases was permanent.
Before anyone decides to put off a potentially lifesaving operation on the basis of these findings, there are a few points to bear in mind. The tests used to measure cognitive ability are very sensitive. Any one of us could "fail" such an exam and still not notice a great difference in our daily life. In addition, this is a preliminary study that lacked a control or comparison group. "I think there's something to this," says Dr. Patrick McCarthy, a cardiac surgeon at the Cleveland Clinic. But he is quick to add that it's not at all clear how much of the decline is due to the bypass and how much to aging.
It's also possible that the surgery doesn't cause mental dysfunction so much as unmask it, in the way that a stress test can reveal an underlying heart condition. After all, if the arteries are clogged, there's a good chance that at least a few blood vessels in your head are having trouble getting oxygen to your brain. Confusion and memory problems can also be a sign of depression, which has its own causes and treatments.