Cognitive Problems in Heart Disease Patients Not Due to Heart-Lung Machines

Long-term memory loss and cognitive problems that heart bypass patients suffer after surgery are due to the underlying coronary artery disease and not the use of a heart-lung machine during surgery, new research shows.

Researchers at the Johns Hopkins University School of Medicine have completed a study that confirms findings from a study completed last year that showed that the heart-lung machines did not cause brain damage. Results of the new study show that all heart disease patients, regardless of whether or not surgery or drugs and arterial stents were used to keep their arteries open, and regardless of whether or not the surgery required a heart-lung machine, were more likely to experience “significant cognitive decline” over the course of the study.

Lead researcher Ola A. Selnes, PhD, a professor in the Division of Cognitive Neuroscience in the neurology department at Johns Hopkins, and her team examined cognitive outcomes in 152 on-pump coronary artery bypass surgery patients, 75 off-pump bypass surgery patients, 99 nonsurgical cardiac comparison subjects, and 69 “heart-healthy comparison subjects,” according to an abstract published in the August issue of The Annals of Thoracic Surgery. All patients with heart disease experienced a decline on 16 different scores of verbal and visual memory when compared to healthy subjects.

“Neuroscientists do not yet have good measures on heart disease and how the burden of this disease impacts brain function,” said senior study investigator and neurologist Guy McKhann, MD, a professor at Johns Hopkins. “If we can eventually figure out how heart disease and declines in brain function are linked over the long term, then it is feasible to think that we can diagnose problems earlier and, ultimately, intervene and prevent, or even lessen, these cognitive problems.”

The results of the study also “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 Selnes.