Public Release: 

Evaluation needed to gauge silent threat lurking within stroke patients

American Heart Association

DALLAS, Sept. 9 - Up to 40 percent of patients with "mini strokes" and ischemic strokes have silent heart disease, so doctors need to evaluate their heart risk even if patients don't have symptoms, according to an American Heart Association/American Stroke Association scientific statement published in today's Circulation: Journal of the American Heart Association.

Stroke survivors found to be at high risk may also need non-invasive testing, according to the statement's lead author Robert Adams, M.D., Presidential Distinguished Chair, Regents Professor of Neurology, at the Medical College of Georgia in Augusta.

Coronary heart disease, transient ischemic stroke (TIA - known as "mini stroke,") and ischemic stroke all result from vascular disease, where blood flow is restricted to either the heart or brain. The panel of researchers found a link between silent heart disease and TIA and with silent heart disease and ischemic strokes originating in large vessels to the brain.

"Compared to patients with strokes caused by blockage in small vessels in the brain, patients with TIA or large-vessel strokes have a higher likelihood of also having coronary artery disease, whether or not they have a clear history of heart disease," Adams said. While there are guidelines for coronary heart disease and managing stroke, there was no summary of how doctors should approach coronary risk in relatively healthy patients with stroke who have no recognized symptoms or history of heart disease, he said. "There are data to indicate that some people already have significant heart disease by the time they have a stroke even though they don't have any recognized symptoms of heart disease," said Adams, past chairman of the American Heart Association's Stroke Council Leadership Committee.

The authors reviewed literature on short- and long-term outcomes of stroke survivors. Overall, they discovered that the risk of heart attack or sudden cardiac death after stroke is much greater in the long term than in the short term.

In a review of short-term studies, the panel found that in the first 90 days after stroke, between 2 percent and 5 percent of stroke patients had cardiac events, many of which were fatal. Adams noted that these studies included people with established heart disease and it was unclear how many people were asymptomatic. In studies with intermediate follow-up (from one month to two years after stroke), heart attacks and cardiovascular deaths ranged from 1.5 percent to 5 percent of stroke patients, which is less common than the recurrent stroke rate.

"We conclude that up to two years after stroke, without an established history, the risk of fatal heart attack compared to having another stroke is relatively modest, but it's important and we want to take it seriously and consider testing to reduce risk in some cases," Adams said.

In long-term population studies that followed patients for up to six years, there was more significant heart disease risk that equaled or surpassed the risk for recurrent stroke, he said. Twenty-four percent to 45 percent of deaths were related to vascular disease other than stroke.

In examining stroke subtypes, people with obvious large-vessel strokes were much more likely to harbor heart disease than those with small-vessel strokes. Therefore, the authors said, doctors should make a stronger case for considering noninvasive heart disease testing in people with large-vessel disease. "This stands to reason because coronary disease is large-artery disease of the heart," he said. "They share even more closely the risk factors related to large artery disease, such as smoking and lipid abnormalities." When it is not obvious whether a stroke is caused by large or small vessel disease, the panel recommends that doctors use the Framingham risk estimation tool. The tool calculates risk factors, such as age, gender, cholesterol, blood pressure, smoking and diabetes to determine a person's level of risk for heart disease within 10 years. Regardless of stroke subtype, a patient whose risk is 20 percent or higher should be considered for further noninvasive testing to detect "silent" heart disease.

The authors recommend that treatment for silent heart disease should be individualized, "and you can't do that until you see the severity of the heart disease after proactive testing," Adams said.

The authors don't recommend routine testing for all stroke patients, and they say testing doesn't need to occur while patients are hospitalized immediately after stroke. However, all people with stroke should undergo a comprehensive assessment and doctors should encourage them to reduce their risk factors for heart disease, via smoking cessation, diet, etc.

"Of course, all stroke patients should be evaluated for the cause of the stroke and appropriate secondary prevention treatments should be instituted as soon as possible," he added.

Further research is needed on asymptomatic patients to determine the risk of heart disease, as well as the cost effectiveness of additional testing and treatment as recommended by this panel, he said.

"Stroke survivors should understand that they need to be concerned about preventing another stroke, but also preventing heart disease, even if they don't have recognized heart disease symptoms," Adams said.

Co-authors are Marc I. Chimowitz, M.D.; Joseph S. Alpert, M.D.; Issam A. Awad, M.D.; Manuel D. Cerqueria, M.D.; Pierre Fayad, M.D.; and Kathryn A. Taubert, Ph.D.

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Editor's note: For more information on stroke, visit the American Stroke Association: strokeassociation.org.

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