An Update on Transient Ischemic Attacks

Janice Hinkle

Disclosures

J Neurosci Nurs. 2005;37(5):243-248. 

In This Article

Secondary Prevention

By definition, a patient who has experienced TIA has no residual neurological deficit, however, approximately 30% of patients who have had a TIA go on to have a stroke within 5 years (Albers et al., 1999). The goal of treatment is to prevent another TIA or stroke by identifying and treating the probable cause. Medical therapy for preventing a recurrence of TIA or stroke may include antiplatelet agents or anticoagulation therapy. Patients with a critical percentage of carotid stenosis may benefit from carotid endarterectomy or stenting. Those with a patent foramen ovale (PFO) will need to have the foramen closed.

Anticoagulants

The treatment of choice for patients with atrial fibrillation (AF) and a recent TIA is anticoagulation. Microscopic emboli are thought to form as the blood pools in the heart when a patient experiences AF. The drug of choice is warfarin sodium (Coumadin) with an international normalized ratio goal of 2.5 (Albers et al., 1999; Wolf et al., 1999). In patients without AF, antiplatelet therapy is recommended.

Antiplatelet Therapy

There is much ongoing debate in the medical literature about antiplatelet agents following TIA. The most commonly recommended drug regimens include acetylsalicylic acid (aspirin), 50–325 mg daily (Albers et al., 1999; Wolf et al., 1999); ticlopidine (Ticlid), 250 mg twice daily (Albers & Easton, 2001; Albers et al., 1999); clopidogrel bisulfate (Plavix), 75 mg daily (Albers et al.); or extended-release dipryridamole 400 mg with Aspirin 50 mg (Aggrenox), daily (Albers & Easton; Albers et al; Sarasin, Gaspoz, & Bounameaux, 2000). Various combinations of these regimens have been tried and the best combinations among types of cerebrovascular events and their subgroups is a source of debate and the subject of several ongoing clinical trails (Tran & Anand, 2004).

Research by Sarasin and colleagues (2000) analyzed the cost effectiveness of antiplatelet regimens in secondary prevention of TIA. Among patients who had experienced TIA but were not candidates for carotid surgery, Aggrenox was the most cost effective. The authors suggest that the incremental costs associated with this regimen were offset by the savings afforded through the avoidance of additional stroke-related costs (Sarasin et al., 2000).

All antiplatelet aggregates are available in oral formulations. Recently the FDA issued a warning about patients who experience choking, gagging, tablets stuck in their throats, and dysphagia while taking certain oral medications (DHHS, 2004). Nurses need to be hypervigilant when administering oral medications to patients who have experienced a TIA that may have included some of these same symptoms. The FDA recommends that patients take all pills with a full glass of water.

Carotid Endarterectomy (CE)

The most common surgical therapy following TIA is CE for eligible candidates. The benefit of carotid endarterectomy for symptomatic patients with severe (70%–99%) carotid stenosis has been known since the early 1990s (North American Symptomatic Carotid Endarterectomy Trial [NASCET], 1991). Patients with asymptomatic carotid artery stenosis of greater than 60% also benefit from CE (Asymptomatic Carotid Atherosclerosis Study, 1995).

More recently the Carotid Endarterectomy Trialists Collaboration pooled and analyzed data from 5,893 patients with 33,000 years of follow-up. Results of the trial suggest that patients who undergo CE for carotid stenosis for more than 70% of the vessel diameter reduce their stroke risk from 26% to 9% (Rothwell, Eliasziw, Gutnikov, Warlow, & Barnett, 2004). In patients with 50%–70% stenosis, the surgery reduces the risk of stroke over 5 years from 22% to 16% (Barnett et al., 1998; Rothwell et al.). The greatest benefit of the surgery is seen in males with recent stroke or TIA symptoms, patients 75 years or older, and in patients with hemispheric rather than ocular symptoms (Rothwell et al.; Winn, 2004). Endarterectomy is most beneficial when performed within the first 2 weeks after a cerebrovascular event (Rothwell et al.; Winn).

Patients with severe carotid artery stenosis who are at high risk due to comorbidities may benefit from angioplasty and carotid stenting. Protective carotid artery stenting with the use of an emboli-protection device may be indicated for certain patients (Yadav et al., 2004).

Patent Foramen Ovale

PFO may cause TIA by permitting emboli to form, escape from the heart, and travel to the brain. Closure can be accomplished using open heart surgery or using a transcatheter closure (Alameddine & Block, 2004; Sommer & Levchuk, 2004)

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