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AHA/ASA Statement Calls Stroke a Cardiac Risk Equivalent


May 30, 2012 — Ischemic stroke patients should be included among those deemed to be at high risk for further atherosclerotic coronary events, concludes a new scientific statement from the American Heart Association (AHA) and American Stroke Association (ASA).
"This is an important message," Daniel T. Lackland, DrPH, from the Medical University of South Carolina in Charleston, and co-chair of the statement writing group, noted in an interview with Medscape Medical News.
"We've typically recognized that if a patient has heart disease or another condition you often treat them differently, maybe more aggressively," he explained. "But it's been unclear what you do with someone who has had a stroke. Do you treat them differently? This has been a big question for a really long time."
"This is a very strong writing team that got together and looked at the evidence and determined that indeed stroke should be recognized as a cardiac risk equivalent and that stroke should be considered in risk models. Until now, this was never clearly stated," Dr. Lackland said.
The American Academy of Neurology (AAN) has affirmed the value of the guideline as an educational tool for neurologists. The statement is published online May 24 in Stroke.
"Rotten in the Basement, Rotten in the Attic"
Reached for comment on the statement, Philip B. Gorelick, MD, MPH, medical director of the Hauenstein Neuroscience Center in Grand Rapids, Michigan, congratulated the authors for their "comprehensive review and conclusions on 2 key questions." Should stroke patients be included among those at high absolute risk for subsequent cardiovascular disease (CVD), specifically coronary heart disease (CHD), and is stroke a relevant outcome in the cluster recommended for use in risk prediction instruments?
"From an intuitive standpoint, the answer to both questions should be yes," said Dr. Gorelick, who was not part of the writing group. "The old bedside teaching adage, 'rotten in the basement, rotten in the attic,' has been passed down to generations of medical students and residents for years," he added. "That is, if you have atherosclerosis of the coronary or peripheral arteries, you will more than likely have it in the cerebral arteries and vice versa."
In the 36-page statement, the writing team cites several reasons to consider stroke patients, particularly patients with atherosclerotic stroke, among the groups of patients at high absolute risk for CHD and CVD.
"First, evidence suggests that patients with ischemic stroke are at high absolute risk of fatal or nonfatal myocardial infarction or sudden death, approximating the ≥20% absolute risk over 10 years that has been used in some guidelines to define coronary risk equivalents," they write.
"Second, inclusion of atherosclerotic stroke would be consistent with the reasons for inclusion of diabetes mellitus, peripheral vascular disease, chronic kidney disease, and other atherosclerotic disorders despite an absence of uniformity of evidence of elevated risks across all populations or patients. Third, the large-vessel atherosclerotic subtype of ischemic stroke shares pathophysiological mechanisms with these other disorders."
The writing group notes that including stroke as a high-risk condition expands by roughly 10% the number of patients considered to be at high risk.
They also note that because of the heterogeneity of stroke, it remains unclear whether other stroke subtypes, including hemorrhagic and nonatherosclerotic ischemic stroke subtypes, should be considered to present the same high levels of risk. The group concludes that further research is needed on this issue.
Dr. Gorelick points out, "With better blood and neuroimaging biomarkers, in the future we may be able to better sort out gaps in our knowledge about germane nonatherosclerotic stroke subtype questions in relation to risk equivalency and CVD prediction."
Add Stroke to Risk Algorithms
For the purposes of primary prevention, the writing group concludes that ischemic stroke should be included among CVD outcomes in absolute risk assessment algorithms.
They say including stroke with myocardial infarction and sudden death among the outcome cluster of CV events in risk prediction instruments is "appropriate because of the impact of stroke on morbidity and mortality, the similarity of many approaches to prevention of stroke and these other forms of vascular disease, and the importance of stroke relative to coronary disease in some subpopulations."
They also note that non-US guidelines often include stroke patients among others at high cardiovascular risk and include stroke as a relevant outcome along with cardiac end points.
"As a take-away message," said Dr. Gorelick, "it is recommended that clinicians continue to follow current risk factor management guidelines for stroke until new risk prediction models are developed, validated and recommended for use. The work by Lackland et al heightens the visibility of stroke and may eventually lead to raising the prevention and treatment bar," he added.
Dr. Lackland has disclosed no relevant financial relationships. A complete list of disclosures for the writing group is listed with the original article. Dr. Gorelick has no disclosed no relevant financial relationships.

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