New Research Suggests Heart Bypass Surgery Increases Risk Of Alzheimer's Disease

The research, which appears in the current issue of the Journal of Alzheimer's Disease (http://www.j-alz.com), pinpoints stress and trauma of the surgery as the major cause for the increased risk.

Ledby Benjamin Wolozin, MD, PhD, professor of pharmacology at BUSM,researchers compared 5,216 people who underwent coronary artery bypassgraft surgery (CABG) and 3,954 people who had a percutaneoustransluminal coronary angioplasty (PTCA) in 1996 and 1997. Over thecourse of five years, 78 of the patients who had bypass surgery and 41of those who had angioplasty developed Alzheimer's disease.

"The coronary bypass patients had a 70 percent increased risk ofdeveloping Alzheimer's disease," said Wolozin, co-author of the study."This increased incidence of neurocognitive degeneration associatedwith heart bypass surgery provides further incentive for more studiesto better characterize the risks of cardiac surgery on the brain."

According to Wolozin, previous studies show some heart surgery patientsexperience memory problems immediately following the procedure.However, at a one-year follow-up most patients regain cognitivefunction.

Researchers believe this early cognitive impairment is an immediate reaction to the stress of surgery.

"Heart bypass surgery represents a traumatic insult to the brain,particularly by reducing oxygen supply to the brain and increasing thestress response," said Wolozin.

"We believe that the compensation that occurs by one year masks anunderlying deficit in the central nervous system caused by the heartsurgery. As individuals age, this underlying deficit might exacerbateprogressive cognitive deficits associated with mild cognitiveimpairment, a precursory phase before diagnosis of Alzheimer's."

Wolozin and his researchers are currently working with researchers fromthe Framingham Heart Study to determine if these same observations canbe duplicated in their studies.

"If these observations are confirmed, there are measures that can betaken to protect the brain during heart bypass surgery," explainedWolozin. "Antioxidants might offer some protection, as well asmemantine, a medication that helps slow the progression of Alzheimer'sdisease. There may also be other neuroprotective agents still indevelopment that could shield the brain from cognitive degenerationduring and following surgery."

The article is "Assessment of the Emergence of Alzheimer's DiseaseFollowing Coronary Artery Bypass Graft Surgery or PercutaneousTransluminal Coronary Angioplasty" by Todd A. Lee, Benjamin Wolozin,Kevin B. Weiss and Martin M. Bednar (Communicated by Craig Atwood). Itappears in the Journal of Alzheimer's Disease, Vol. 7, Number 4published by IOS Press.

About the Journal of Alzheimer's Disease
The Journal of Alzheimer's Disease (www.j-alz.com)is an international multidisciplinary journal to facilitate progress inunderstanding the etiology, pathogenesis, epidemiology, genetics,behavior, treatment and psychology of Alzheimer's disease. The journalpublishes research reports, reviews, short communications, bookreviews, and letters-to-the-editor. The journal is dedicated toproviding an open forum for original research that will expedite ourfundamental understanding of Alzheimer's disease.

About IOS Press
Commencing its publishing activities in 1987, IOS Press (www.iospress.com)is a rapidly expanding scientific, technical, medical and professionalpublishing house focusing on a broad range of subject areas.Headquartered in Amsterdam, IOS Press publishes approximately 100 newbooks per annum and 70 international journals, covering topics rangingfrom computer science and mathematics to medicine and the naturalsciences. Electronic access to all journals is now available. IOS Pressalso maintains offices in the Washington, DC area and Berlin and aco-publishing relationship with Ohmsha, Ltd (Tokyo).