When Bill Clinton, 58, underwent quadruple coronary bypass surgery on Labor Day, the former president, like most Americans who have similar operations, spent time – in his case, 73 minutes – hooked up to a heart-lung machine while surgeons re-routed blood vessels to his heart.
With luck and his relative youth and health going for him, Clinton will hopefully rebound fit in both heart and mind from the bypass surgery, in which doctors replace clogged arteries to the heart with veins and arteries taken from elsewhere in the body.
But many people who go through the procedure — as 305,000 Americans did in 2001, the latest year for which figures are available — find that at least for a few days, often for weeks and sometimes for years afterwards, their brains don’t work as well as they did before.
Doctors who acknowledge the problem -and some still pooh-pooh it – call it post-surgical “neurocognitive deficits.” Everybody else calls it “pump head,” reflecting the widespread, though unproven, belief that it’s the process of blood being pumped through a heart-lung machine while the heart is stopped for surgery that causes small blood clots, air bubbles or other debris to travel to the brain, disrupting memory.
Nobody really knows how common “pump head” is because, outside of research studies, most cardiac patients aren’t tested on intellectual function before and after surgery. Detecting all but the most subtle cognitive changes “depends on how hard you look,” said Dr. William Cohn [cq], director of minimally invasive surgical technology at the Texas Heart Institute in Houston.
Nonetheless, it has now been “convincingly demonstrated that measurable cognitive dysfunction is actually a common complication of CABG (coronary artery bypass graft) surgery, with an incidence of 80 to 90 percent at hospital discharge,” as Duke University researchers Dr. Daniel B. Mark [cq] and Dr. Mark F. Newman [cq]put it in an editorial in the Journal of the American Medical Association in 2002.
Even five years after discharge, 42 percent still show measurable cognitive decline, Mark and Newman found in their own study, published in 2001 in the New England Journal of Medicine, though some of this might have been due to normal aging.
In most patients with “pump head,” the deficits are real, but small. “It’s not that you can’t solve a problem,” said Mark, “but that you can’t solve it as quickly.”
Many cardiologists, among them Dr. Christopher Cannon [cq] of Brigham and Women’s Hospital in Boston, also believe that deficits are most likely to occur in older patients who, in addition to having clogged arteries to the heart, may have blockages in blood vessels in the brain as well. In other words, what some see as a consequence of heart surgery may be a consequence of generalized atherosclerosis.
At the moment, there is no cure for “pump head.” Nor do doctors understand why some patients who get it get better over time and others do not.
Though it’s not clear today that the heart-lung machine is the real culprit in “pump head,” many doctors for years assumed it was and focused their prevention efforts on the machine itself.