TIA Management: Emphasis on Urgent Evaluation and Treatment
Abstract & Commentary
By Dana Leifer, MD, Associate Professor, Neurology, Weill Medical College, Cornell University. Dr. Leifer reports no financial relationship relevant to this field of study.
Synopsis: Patients with transient ischemic attacks should usually be admitted to the hospital and receive rapid evaluation and treatment.
Source: Johnston, SC, et al. National Stroke Association Guidelines for the Management of Transient Ischemic Attacks. Ann Neurol. 2006:60:301-313.
A growing body of evidence indicates that there is a significant risk of stroke in the days immediately after a transient ischemic attack. Johnston et al found that 5% of TIA patients had a stroke within 48 hours and another 5% had a stroke within 90 days. Several other groups have obtained similar results. In addition, Rothwell et al showed that approximately 20% of stroke patients have a TIA before their stroke and that of these, 26% occurred on the day of the stroke or the day before the stroke, and an additional 19% occurred between 2 and 7 days before the stroke (Neurology. 2005;64:817-820). Taken together, these data indicate a need to take TIAs seriously, to initiate appropriate preventive treatment quickly, and to facilitate rapid intervention if a stroke develops.
In this background, the National Stroke Association (NSA) established an expert panel to develop guidelines for TIA management. The panel was chosen objectively on the basis of publications related to TIA and stroke. After a literature search, the quality of evidence was rated, and recommendations were derived from the rated evidence. Multiple rounds of comments from the panel were used to derive a consensus, and panel members were excluded from contributing to topics for which they had a possible conflict of interest. This approach was designed to avoid bias in selection of experts, to prevent overweighting of dominant personalities in the consensus process, and to permit efficient updating of the recommendations.
The guidelines emphasize the need for timely treatment of TIAs. The chief points are:(1) Hospitalization should be considered for all patients presenting within 48 hours of their first TIA to facilitate thrombolytic therapy if a stroke develops and to begin secondary prevention rapidly. An important corollary that the guidelines do not address, however, is that if patients are admitted, they need to be monitored closely to minimize the delay in recognizing in-hospital strokes. (2) Timely referral to a hospital is also advisable for all patients within one week of a TIA and hospital admission is generally recommended for patients with crescendo TIAs, TIAs lasting more than one hour, > 50% carotid stenosis if symptomatic, known cardioembolic sources, known hypercoagulability, and combinations of other factors placing patients at high risk based on recently developed scales for rating stroke risk after TIA (Stroke. 2006;37:320-322).
The guidelines also make recommendations about the infrastructure that should be available for evaluation of TIA patients: (1) Local protocols should be established to identify patients who will be admitted and those who will be referred for outpatient evaluation. Specialty clinics for outpatient evaluation within 24 to 48 hours should be available for patients who are not admitted. Patients who are not admitted should be instructed to return at once if they have recurrent symptoms. (2) Patients not admitted should have access within 12 hours to CT or MRI, EKG, and carotid Doppler. These should be done within 24 to 48 hours if they are not done in an emergency room. If they are done and are normal, a longer period of up to 7 days may be appropriate for further work-up. (3) Patients with TIA within 2 weeks who are not admitted should be worked up within 24 to 48 hours (ie, carotid Doppler, blood work, cardiac evaluation such as EKG, rhythm strips, and echocardiography). (4) Medical assessment should at least include EKG, CBC, electrolytes, creatinine, glucose, and lipid studies.(5) Imaging should include CT or MRI for all patients to rule out structural lesions such as acute stroke, subdural hemorrhage, and brain tumor (25% or more of patients with a clinical TIA may actually have had a small stroke). Some form of vascular imaging (ie, ultrasound, CTA, or MRA) should also be performed. Catheter angiography remains the gold standard, but should be used for diagnostic purposes primarily when the other tests are discordant or cannot be performed. (6) Cardiac evaluation with transthoracic or transesophageal echocardiography and testing for right to left shunting is advised in patients under 45 years of age if other studies do not identify a cause for the TIA.
The guidelines go on to make specific recommendation for antithrombotic therapy and for treatment of other specific risk factors that are identified during the work-up. These are important and emphasize the need for antiplatelet therapy for most patients, anticoagulation when indicated, and aggressive management of risk factors including carotid stenosis, hypertension, hyperlipidemia, and diabetes. The recommendations are largely similar to those of the American Heart Association's 2006 statement on stroke prevention (Stroke. 2006;37:577-617). Those guidelines, however, did not address the importance of rapid evaluation of TIA patients. The main importance of the new NSA guidelines is that they stress the need for rapid evaluation and treatment of TIA patients.