Heart Disease Causes Long-Term Brain Damage Following Bypass Surgery

A new study suggests that long-term memory losses and cognitive problems experienced by heart bypass surgery patients are due to the underlying coronary artery disease (CAD) itself, and not ill after-effects from having used a heart-lung machine.

Researchers at Johns Hopkins University (JHU; Baltimore, MD, USA) conducted a prospective, nonrandomized, longitudinal study that compared cognitive outcomes after on-pump coronary artery bypass surgery (152 patients); off-pump bypass surgery patients (75 patients); nonsurgical cardiac comparison subjects who opted for drugs and arterial stents to keep their blood vessels open instead of bypass, with none requiring use of a heart-lung device (99 patients); and 69 heart-healthy comparison (HHC) subjects. The primary outcome measure was change from baseline to 72 months in cognitive domains that included verbal memory, visual memory, visuoconstruction, language, motor speed, psychomotor speed, attention, executive function, and a composite global score.

The study results showed that there were no consistent differences in 72-month cognitive outcomes among the three groups with CAD. The CAD groups had lower baseline performance, and a greater degree of decline compared with HHC. The degree of change was small, and none of the groups was substantially worse at 72 months compared with baseline. According to the researchers, the results indicate that management strategy for CAD is not an important determinant of long-term cognitive outcomes. The study was published in the August 2009 issue of Annals of Thoracic Surgery.

"Our results hammer home the message that heart-lung machines are not to be blamed for cognitive declines observed years later in people who have had bypass surgery,” said lead study investigator Ola Selnes, Ph.D., a professor in the division of cognitive neuroscience in the neurology department at JHU.

Postperfusion syndrome, also known as "pumphead syndrome,” is a constellation of neurocognitive impairments attributed to cardiopulmonary bypass (CPB) during cardiac surgery. The symptoms of postperfusion syndrome are subtle and include defects associated with attention, concentration, short-term memory, fine motor function, and speed of mental and motor responses. The short-term syndrome led many surgeons and patients alike to assume that long-term losses must also be due to use of heart-lung machines, an assumption proven wrong by the latest evidence.

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