Acute coronary syndrome patients at increased risk of stroke

Patients hospitalized with chest pain or heart attack symptoms are at an increased risk of stroke even after being discharged, according to a study published in Circulation: Journal of the American Heart Association.

“In spite of current therapy, their stroke risk is substantially higher than that of the general population,” said co-author Keith A. A. Fox, M.B., Ch.B., professor of cardiology at the Royal Infirmary of Edinburgh in the United Kingdom.

Acute coronary syndrome (ACS) is an umbrella term for conditions that cause chest pain due to insufficient blood supply to the heart muscle (acute myocardial ischemia). It includes unstable angina, or chest pain, and heart attack. Nearly 1.7 million Americans with ACS were discharged from hospitals in 2002, according to the American Heart Association. This includes ACS as both primary and secondary discharge diagnoses.

Heart attack patients are known to be at an increased risk of stroke, but few studies have investigated the incidence and outcome of stroke in patients with ACS.

“Although there has been a major focus on cardiac-related outcomes after ACS, there are limited data on stroke outcomes in ‘real world’ unselected populations,” said Fox, who is co-chair of the study. “This is highly relevant, not only because of the bleeding risks associated with clot-busting therapies, but also because ACS patients have more diffuse vascular disease, including cerebrovascular disease.”

The researchers used data from the Global Registry of Acute Coronary Events (GRACE) study. The multinational observational registry included 35,233 patients at least 18 years old who were admitted to hospitals with ACS symptoms and who had ACS-consistent electrocardiographic (ECG) changes, biochemical markers of heart tissue damage and/or documented coronary artery disease. Patients were followed for about six months after hospital discharge.

Within the first six months after admission, 1.6 percent of ACS patients had experienced a stroke. About half of the strokes occurred while the patients were in the hospital.

The incidence rate was “clearly lower” than the incidence of in-hospital death, reinfarction, heart failure, atrial fibrillation, acute renal failure or major bleeding, said lead author Andrzej Budaj, M.D., Ph.D., professor of medicine and director of the department of cardiology at Grochowski Hospital’s Postgraduate Medical School in Warsaw, Poland.

Although it was uncommon in ACS patients, stroke was associated with high mortality. About one in three in-hospital strokes was fatal (32.6 percent); one in five post-discharge strokes was fatal (20.9 percent).

Patients who had a stroke in the hospital were six times more likely to have another after discharge.

During the hospital stay, the most important risk factor was coronary artery bypass grafting (CABG), a surgical procedure to restore blood flow to the heart. Patients who developed atrial fibrillation during their ACS event and those with a history of stroke were also at particularly high risk of stroke.

“Stroke risk needs to be in the mind of cardiologists following patients after ACS,” Fox said. “More aggressive anti-platelet and anti-thrombin therapies may reduce the frequency of thrombo-embolic stroke, together with conventional but systematically applied blood pressure lowering and lipid lowering.”

Other risk reduction strategies involve simple lifestyle changes. The American Heart Association recommends that people reduce their sodium, cholesterol and saturated fat intake to help control blood pressure and cholesterol levels, as well as quit smoking, manage diabetes and increase their physical activity.

Co-authors are Katarzyna Flasinska, M.D.; Joel M. Gore, M.D.; Frederick A. Anderson, Jr., Ph.D.; Omar H. Dabbous, M.D., M.P.H.; Frederick A. Spencer, M.D.; and Robert J. Goldberg, Ph.D.

The GRACE study is funded by an unrestricted grant from Sanofi-Aventis to the Center for Outcomes Research at the University of Massachusetts Medical School in Worcester, Mass.