The American Heart Association/American Stroke Association (AHA/ASA) released updated guidelines to prevent subsequent stroke in survivors of ischemic strokes or transient ischemic attacks (TIAs). Specifically, the guidelines—which were published in the January 2011 issue of Stroke—include new recommendations for treating metabolic syndrome, stenting of the carotid artery, and atrial fibrillation, among other updates. The update revised previous recommendations from 2006 and reflected new evidence from recent investigations and analyses pertaining to secondary stroke prevention. This guideline is one of five “flagship” evidence based statements from the AHA/ASA, which are revised every 3 years. They are designed to assist clinicians in making important treatment decisions after stroke or TIA.
Metabolic Syndrome & Stenting Updates
Among the new recommendations made in the section on metabolic syndrome is that clinicians are now advised to treat individual components that are also stroke risk factors, particularly dyslipidemia and hypertension, in order to prevent a second stroke or TIA in individuals with metabolic syndrome. All patients with carotid artery stenosis and a TIA or stroke should receive optimal medical therapy, including antiplatelet therapy and statins, as well as risk factor modifications. Another important note is that the utility of screening patients for metabolic syndrome after stroke is unknown, so more research is necessary in this component of stroke management.
“As the data continue to shed light on emerging therapies and technologies, the hope is that we’ll be able to decrease the burden of stroke and TIA more in the future.”
The section on carotid artery stenting (CAS) for extracranial symptomatic carotid disease was also updated because of recent large clinical trials. CAS can be used as an alternative to surgery for symptomatic patients at average or low risk for complications when the diameter of the lumen of the internal carotid artery is reduced by greater than 70% based on noninvasive imaging or by more than 50% as seen with catheter angiography. For certain patients with symptomatic high-grade carotid stenosis and factors that make carotid endarterectomy more difficult, CAS is now considered a reasonable alternative. It’s also reasonable to perform CAS when operators have established periprocedural morbidity and mortality rates of 4% to 6%.
The current data are stronger for the use of carotid artery endarterectomy (CAE) when treating carotid artery stenosis. CAE is now recommended for patients with symptomatic severe stenosis (more than 70%) and moderate stenosis (50% to 99%) if the perioperative morbidity and mortality risk is estimated at less than 6%. Neither CAE or CAS, however, is recommended when stenosis is less than 50%.
Atrial Fibrillation Updates
For stroke survivors who have atrial fibrillation (AF) but are unable to take oral anticoagulants, aspirin monotherapy is recommended. Temporary interruption of oral anticoagulation is problematic for patients with AF at high risk of recurrent stroke. But if necessary, minimizing interruption time and bridging therapy with a low-molecular-weight heparin is recommended. The guidelines also provide other recommendations for patients with intermittent or permanent AF and special populations. AF is an area of ongoing research and drug development, so it’s likely that this section of the guidelines will be updated in the near future.
A Work in Progress
The AHA/ASA guidelines for secondary prevention of stroke and TIA are a work in progress because many drug therapies and other interventions are being investigated. As the data continue to shed light on emerging therapies and technologies, the hope is that we’ll be able to decrease the burden of stroke and TIA more in the future. Until then, clinicians are encouraged to review the guideline update—available for everyone online at http://stroke.ahajournals.org—when managing these patients.