Transient ischemic attack guidelines will change how you treat patients
January 1, 2000 6 minutes read
Transient ischemic attack guidelines will change how you treat patients
Options emphasize treatment and prevention
When a patient comes to your ED with a transient ischemic attack (TIA), your standard practice may be to stabilize them and discharge for follow-up with a neurologist or primary care physician once their symptoms resolve. But according to new guidelines, if you do this, patients may return with a stroke.1
"There is a change in management of TIA patients, namely that they should no longer be sent straight out of the ED once their symptoms have resolved," warns Susan Unipan Rodriguez, BSN, CNRN, nurse coordinator for the National Institutes of Health/National Institute for Neurological Disorder and Stroke (NINDS), Stroke Branch/Stroke Diagnostics and Therapeutics, based in Bethesda, MD.
"We need to take a more thorough look into what has caused the TIA to occur, so that we don’t send them out from the ED, only for them to return with a full-blown stroke," she emphasizes.
The new guidelines for the management of TIAs, published by the Dallas-based American Heart Association (AHA) Stroke Council, give exciting new options for prevention and treatment in the ED. (See excerpt of guidelines, pp. 27-29.) The guidelines are a supplement to the AHA’s 1994 guidelines and were prompted by scientific advances for patients with TIAs.
"That is the challenge," Rodriguez says. "You need to piece together which of the stroke risk factors might have caused the TIA to occur, what areas of the brain might be involved, and what interventions are needed now for stroke prevention."
Here are some key changes in the new TIA guidelines:
• Perform a thorough stroke work-up.
Some TIAs only last five or 10 minutes, so by the time the patient arrives in the ED, symptoms may have resolved. Still, the patient should not be discharged without a thorough stroke work-up, urges Rodriguez.
"This includes risk factor assessment to see how risk factors such as hypertension, diabetes, and smoking might be involved, and how they can be modified, as well as looking for atrial fibrillation through cardiac monitoring," says Rodriguez. (See story on rapid diagnostic unit for TIA patients, p. 31.)
The TIA work-up now includes such diagnostic interventions as echocardiogram and carotid ultrasound to determine if there is plaque buildup or stenosis in the carotid arteries, Rodriguez notes. "These are tests which are obtained to determine the etiology of a stroke," she says. "If we can identify the cause of the TIA, hopefully we can alter our treatment to prevent a stroke from occurring in the future."
Up to 41% of patients who present with a stroke have had a TIA in the past, so be proactive to prevent strokes, stresses Rodriguez. "The goal is to determine what has caused the TIA to occur."
To reduce risks, patients should stay for observation, cardiac monitoring, and diagnostic testing, Rodriguez advises. "The risk of stroke following a TIA is greatest within hours to days, so it’s very important we modify risk factors as soon as possible," she says.
Previously, TIA patients were managed on an outpatient basis. "TIA is now looked at as an emergency which requires a comprehensive assessment and tailored treatment, depending on the cause and the patient’s history," says Rodriguez.
• Modify risk factors immediately.
The guidelines stress that risk factors such as hypertension should be identified immediately. "For example, we can alter antihypertensive or diabetic medications while emphasizing the need for patients to be compliant with their medications," says Rodriguez.
Take a thorough history to identify the risk factors patients present with, says Rodriguez. "Once that is nailed down, you can begin to modify those risk factors immediately," she explains.
• Decrease dosage of aspirin.
Previously, there was a belief that the more aspirin patients were taking, the better the prophylaxis, but that’s not the case, Rodriguez explains. "Several recent studies have found that not to be true. The most effective dose of aspirin is somewhere between 81 mg to 325 mg, depending on what has been determined to be the cause of the TIA."2,3,4
The front line treatment is still almost always aspirin, says Judith Ann Spilker, RN, BSN, cerebrovascular research coordinator in the department of emergency medicine at University Hospital, University of Cincinnati Medical Center and consultant for the National Stroke Association, based in Englewood, CO.
"It has many advantages," she says. "One major advantage is it’s inexpensive, and compliance goes up when the cost is low, particularly with elderly patients."
But if a patient fails aspirin alone and has a new event, the next step of management is needed, Spilker says. "There are several choices now. Someone has to decide which is the best choice for that patient, based on the risk factors, family history, and diagnostic information," she explains. (See related story on new medication options for TIA patients, p. 30.)
If patients come in with TIA, ask them if they are on aspirin therapy, recommends Rodriguez. "If they are, then aspirin alone might not be the best stroke prevention for them," she says. "There are definitely alternatives for patients now if they don’t tolerate aspirin, either in conjunction with aspirin or as an alternative."
Patients may not be able to tolerate aspirin, if they have bleeding disorders or gastric disturbances, notes Rodriguez. Also, aspirin alone may not be adequate for some patients, notes Spilker.
"An obese smoking diabetic female with birth control pills is a setup for stroke no matter what you do, and aspirin may not be enough for her," she says.
• Know that more patients are eligible for surgery.
There are new thresholds for surgical management, Rodriguez reports. "It used to be that only patients who had symptomatic carotid stenosis greater than 70% were recommended for surgery."
Now, for patients who are symptomatic from their stenosis, surgery is recommended for patients with carotid stenosis of 50% or greater. "So they have dropped the threshold for surgical intervention," she adds.
If a patient has symptoms, they need intervention, stresses Rodriguez. "Carotid endarterectomy can work wonders for these patients."
A carotid ultrasound is a portable machine, so carotid endarterectomy can be performed in the ED, Rodriguez says. "That’s the best way to do it, so you can immediately rule in or out carotid artery atherosclerosis as the cause for the TIA."
Also, an echocardiogram can be performed as a portable test at the patient’s bedside in the ED to rule out a cardiac source of embolus, Rodriguez says.
• Perform an acute magnetic resonance imaging (MRI).
There is a change from administering only the standard computed tomography (CT) scan for patients with strokelike symptoms to administering an emergent MRI, says Rodriguez. "Patients should be sent directly from the ED for an emergent MRI as part of the acute diagnostic testing, because important information can be obtained."
With an TIA, ischemia often shows up immediately through diffusion MRI, says Rodriguez. "The ischemia can take six to 12 hours to show up on a CT scan, and TIAs often do now show up at all," she explains.
A significant amount of valuable information can be obtained from the MRI, Rodriguez says. "You can see imaging of the vessels in the brain immediately, along with changes in cerebral blood flow and the presence and location of ischemia and intracranial blockages."
A CT scan will show you whether intracranial blood is present. However, with MRI, you can immediately check for the presence of both blood and ischemia, notes Rodriguez.
References
1. AHA Scientific Statement. Supplement to the guidelines for the management of transient ischemic attacks: A statement from the Ad Hoc Committee on Guidelines for the Management of Transient Ischemic Attacks, Stroke Council, American Heart Association. Stroke 1999; 30:2,502-2,511.
2. Patrono C, Collor BS, Dalen JE, et al. Platelet-active drugs: The relationships among dose, effectiveness, and side effects. Chest 1998; 114(suppl 5):470-488.
3. Gorelick P, Born G, D’Agostino R, et al. Therapeutic benefit: Aspirin revisited in light of the introduction of clopidogrel. Stroke 1999; 30:1,542-1,547.
4. Albers GW, Tijssen JG. Antiplatelet therapy: New foundations for optimal treatment decisions. Neurology 1999; 53(suppl 4):25-31.
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