Coronary Bypass Surgery May Be Associated with Increased Risk of Stroke and Long-Term Cognitive Changes; Patients with Risk Factors for Cerebrovascular Disease at Greatest Risk

7/22/2002

From: Elizabeth Wilson or Jim Prescott, 312-335-4078 (Chicago) or 46-872720-05 (Stockholm, July 20-25), both of the Alzheimer's Association (USA); e-mail: media@alz.org

STOCKHOLM, Sweden, July 22 -- New findings being reported this week at the 8th International Conference on Alzheimer's Disease and Related Disorders suggest that coronary artery bypass grafting (CABG), an effective technique for treating heart disease, may be associated with an increase risk of stroke, short-term memory problems and long-term cognitive changes.

Guy M. McKhann, M.D., and his colleagues at Johns Hopkins School of Medicine in Baltimore, Md., collected data on 3,300 patients undergoing CABG between 1997 and 2001. The researchers at Johns Hopkins found that after this type of surgery, 2.6 percent of the patients suffered a stroke and 6.8 percent developed acute confusion or short-term memory problems. Both outcomes are associated with an increase in hospital length of stay and death.

The researchers then identified the following as risk factors for stroke, acute confusion and the combination of the two: hypertension, diabetes, carotid bruit (abnormal sound heard through a stethoscope when listening to blood flow in the carotid artery), previous stroke, age and time on the cardiopulmonary bypass pump (heart-lung machine). The researchers found that there is a 50 percent increase in the probability of acute confusion for each hour on the bypass pump.

During an "on-pump" coronary bypass procedure, the heart is stopped and blood is rerouted around the heart and lungs, but circulated through the rest of the body with the aid of a heart-lung machine or bypass pump.

McKhann and colleagues evaluated changes in patients' cognitive function at one month, one year and five years following surgery. In the short term, they found that cognitive changes involving memory and attention generally improved within one year after surgery. However, between one year and five years following surgery, the researchers identified cognitive declines. It was noted that individuals with more severe cerebrovascular disease at baseline are more likely to experience this delayed decline.

Based on this research, risk factors for stroke and acute confusion following CABG have been developed.

"There appears to be a sub-population of patients undergoing coronary bypass surgery, with risk factors for cerebrovascular disease, who are at greater risk for stroke, cognitive decline and long-term cognitive changes," said McKhann, professor of Neurology at Johns Hopkins School of Medicine. "For this population of people, it may be beneficial to consider alternative cardiac interventional techniques in addition to carefully managing diabetes, hypertension and other related risk factors."

According to the American Heart Association, 571,000 coronary artery bypass graft procedures were performed in 1999.

The Alzheimer's Association is hosting the 8th International Conference on Alzheimer's Disease and Related Disorders, July 20-25, 2002, in Stockholm, Sweden. The conference is the largest gathering of Alzheimer researchers in history. As many as 4,000 researchers from around the world will present and discuss the findings of nearly 2,000 studies on the prevention, diagnosis and treatment of Alzheimer's disease.

The Alzheimer's Association is the premier source of information and support for the 4 million Americans with Alzheimer's disease. The largest private funder of Alzheimer research in the United States, the Association has committed $138 million toward research into the disease.

--- Abstract No. 26

Title: Neurologic and Cognitive Outcomes After Coronary Bypass Surgery

Session: Sunday, July 21, 10:30 a.m.-12:30 p.m.

Researcher: Guy M. McKhann

--- Editor's Note: News releases of selected research presented at the 8th International Conference on Alzheimer's Disease and Related Disorders are available on the Alzheimer's Association's Web site, at www.alz.org/internationalconference/newsroom.htm. Scientific abstracts are accessible on the Web at http://www.alz.org/internationalconference/programs.htm, then click on Program Navigator link.