Dr. Devin R. Harris (biography and disclosures)
What I did before
Transient ischemic attacks are a major risk factor for stroke. The management of transient ischemic attacks (TIA) has changed significantly in the last 10 years. Prior to the introduction of relatively new evidence, TIA’s were considered a benign condition; as physicians, we were thankful that the patient’s symptoms resolved and no specific therapy was prescribed.
What changed my practice
In 2000, a landmark article outlined the early risk of stroke after TIA – 5% risk of stroke within 2 days after a TIA and 10% risk of stroke within 90 days1. This estimate was much higher than was previously documented in the literature. Subsequent studies repeated those findings and a meta-analysis published in 2007, found the risk of stroke after 2, 7, and 30 days to be 9.9%, 13.4%, and 17.3%, respectively2; clearly outlining the very high short-term risk of stroke after a TIA.
In 2002, a group of experts proposed a change in the definition of TIA from 24 hours to 1-hour duration of symptoms3. This was based on advancements in the knowledge of the pathophysiology of cerebral ischemia, improved imaging and new acute stroke therapies. The intention was to move from an antiquated, arbitrary, time-based definition to a “tissue-based” definition, along the same lines as the distinction between angina and myocardial infarction.
Most significantly, what changed my practice was the introduction of two important studies that proved that early intervention after a TIA significantly reduced the incidence of subsequent stroke. The EXPRESS trial4 and the SOS-TIA trial5 showed that early intervention after a TIA works; administration of antiplatelet agents, management of lipids and blood pressure, anticoagulation for atrial fibrillation and early referral for carotid endarterectomy surgery, if instituted urgently, makes a significant difference. In the EXPRESS trial, the 90-day risk was reduced from 10.3% to 2.1% – a stunning 80% relative risk reduction.
What I do now
Any patient who presents with a history or symptoms consistent with a TIA now is treated with the same urgency as a patient who presents with unstable angina. In an emergency department setting, screening laboratory tests are ordered (complete blood count, electrolytes, coagulation profile, glucose), an electrocardiogram performed, and imaging ordered urgently (CT or MRI of the head and cerebrovascular imaging). An antiplatelet medication is given as soon as imaging is performed. Neurological consultation is requested urgently, depending on patient risk and findings from initial investigations. Anticoagulation for patients with atrial fibrillation is started early and referral to a vascular surgeon for urgent carotid endarterectomy is obtained for those with moderate or severe carotid stenosis.
In an outpatient setting, a patient with a recent TIA may be urgently referred to one of many TIA clinics throughout the province (see TIA Rapid Assessment Clinics in British Columbia6). If urgent access is problematic, the patient may also be referred directly to the nearest emergency department for assessment and management. As shown in the SOS-TIA trial5, administration of an antiplatelet medication may be started in an outpatient setting, prior to completion of brain imaging.
References: (Note: Article requests might require a login ID with the BC College of Physicians website or UBC)
2. Wu CM, McLaughlin K, Lorenzetti, DL, Hill, MD; Manns BJ, Ghali WA. Early Risk of Stroke After Transient Ischemic Attack: A Systematic Review and Meta-analysis. Arch Intern Med. 2007;167(22):2417-2422. (View article with CPSBC or UBC)
3. Albers GW, Caplan LR, Easton JD, Fayad PB, Mohr JP, Saver JL, Sherman DG; TIA Working Group. Transient ischemic attack—proposal for a new definition. N Engl J Med. 2002; 347: 1713–1716. (View article with CPSBC or UBC)
4. Rothwell PM, Giles MF, Chandratheva A, Marquardt L, Geraghty O, Redgrave JNE, et al on behalf of the Early use of Existing Preventive Strategies for Stroke (EXPRESS) study. Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study): a prospective population-based sequential comparison. Lancet 2007; 370 (9596): 1432-1442. (View article with CPSBC or UBC)
5. Lavallée PC, Meseguer E, Abboud H, Cabrejo L, Olivot JM, Simon O, et al. A transient ischaemic attack clinic with round-the-clock access (SOS-TIA): feasibility and effects. Lancet Neurol 2007; 6(11): 953-60. (View article with CPSBC or UBC)
6. British Columbia Stroke Strategy. TIA Rapid Assessment Clinics in British Columbia. Read online