Transient Ischemic Attacks Transient Ischemic Attacks Myths, Controversies and Pitfalls Myths, Controversies and Pitfalls Diane M. Birnbaumer, M.D., FACEP Disclosure: Dr. Birnbaumer has no relationships Professor of Medicine with entities producing, marketing, University of California, Los Angeles re-selling, or distributing health care goods or services consumed by, or Senior Faculty used on, patients. Department of Emergency Medicine Harbor-UCLA Medical Center TIA TIAs: The Issues The Scope of the Problem “Incidence” What IS a TIA? Around 300,000 How do we work up these patients? cases per year How should we dispo these patients? Up to 1 in 15 elderly Admit? patients will have a Neurology consultation urgently? TIA Neurology or PCP follow-up? 12-30% of stroke patients have How soon should they follow up? antecedent history of What, if any, medications are indicated? TIA TIA The Scope of the Problem What IS a TIA, anyway? Both over- and underdiagnosed Particularly by non-neurologists Agreement on diagnosis even problematic between neurologists Progression to stroke is major concern… cerebrovascular disease is 3 rd to 4 th leading cause death in US 1
What IS a TIA? What IS a TIA? 1975 1975 NIH definition… the issues NIH definition “A transient ischemic attack is a sudden Based on arbitrary 24 hour time limit focal neurologic deficit lasting for less than Diagnosis made on temporal course 24 hours, of presumed vascular origin, rather than on pathophysiology and confined to an area of the brain or eye perfused by a specific artery” Assumes no permanent brain injury Implies TIA is a benign entity What IS a TIA? What IS a TIA? Recent views Recent views… continued Terms began cropping up… TIA is like “unstable angina of the brain” “Mini-stroke” TIA is a neurologic emergency “Transient stroke” Requires urgent / emergent workup “Transient brain attack” MAY cause permanent brain injury “Warning stroke” Led to redefinition of TIA… More advanced imaging shows damage in up to 50% of TIA patients (old definition) What IS a TIA? TIA: Presentation 2002 Abrupt onset of symptoms TIA Working Group definition Specific symptoms determined by “A TIA is a brief episode of neurologic vascular distribution dysfunction caused by focal brain or retinal Usually lasts < 30 minutes ischemia, with clinical symptoms typically Majority < 10 minutes lasting less than one hour, and without evidence of acute infarction.” Albers, et al: NEJM 347;2002:1713-1716. 2
TIA: Presentation TIA: Presentation Abrupt onset of symptoms Current definition of TIA (2009) eliminated a time frame Specific symptoms determined by vascular distribution “A transient episode of neurological dysfunction cause by focal brain, spinal Usually lasts < 30 minutes cord, or retinal ischemia, without acute Majority < 10 minutes infarction” What is the implication of this for you? Now is a tissue-based definition, not a Much of evaluation will be based on history time-based definition – patient / family / bystanders Emphasis is now on neuroimaging TIA TIA: Presentation Time sensitive diagnosis if still New definition led to a new clinical symptomatic (TIA vs CVA?) entity - radiographic infarction without lingering symptoms Need to consider broad differential diagnosis What does that mean? By old definition – fit TIA diagnosis Creates a new entity: TSI - Transient Symptoms with Infarction Likely that CVA, TSI and TIA are a spectrum like the cardiac ACS spectrum TIA Differential Diagnosis TIA: Evaluation Hypoglycemia / hyperglycemia Structural brain lesion CNS infection Todd’s paralysis Epilepsy Complicated migraine MS flare Syncope Labyrinthine disorders Hyperventilation syndrome / panic attack SAH… etc, etc 3
TIA: Evaluation TIA: Testing in the Urgent Setting Rapid glucose Thorough history and physical exam Detailed neurologic exam warranted CBC Include exam for subtle findings Chem panel Cardiac exam: Rate, rhythm, murmurs ECG Carotids for bruits Coagulation studies Goal is to determine if episode was a true TIA or not Head CT If so, helpful to determine anterior or MRI posterior circulation involved Vascular imaging TIA: Testing in the Urgent Setting TIA: Testing in the Urgent Setting Rapid glucose There are a gazillion new tests coming down the pike CBC We’ll see if they pan out… don’t hold Chem panel your breath ECG Coagulation studies Head CT MRI Vascular imaging TIA: Neuroimaging TIA: Neuroimaging Now that TIA is a tissue-based diagnosis, Why DWI MRI? neuroimaging becoming more critical Shows areas of restricted diffusion associated with cytotoxic edema Recommended by AHA/ ASA that it be Much more sensitive than traditional MRI done within 24 hours of symptom onset False negatives seen in 3-17% Diffusion weighted imaging MRI is the Very early ischemia preferred first imaging modality Small infarcts – especially internal capsule and However, CT is most common study first brainstem performed 4
TIA: Neuroimaging TIA: Neuroimaging Diffusion-weighted MRI Issue: Does diffusion-weighted MRI add supplemental predictive value to risk Show lesions in 16-67% of patients with TIA stratification in TIA? Positive studies = high-risk group Doubles the risk of subsequent vascular event Some studies suggest positive study independent risk factor for subsequent stroke 4-fold increase if positive MRI plus TIA symptoms lasting > 1 hour More studies addressing it as independent Positive studies associated with… risk factor required High-grade large vessel stenosis Begs issue of routine availability of 24/7 MRI Cardioembolic source scanning TIA: Neuroimaging TIA: Further Studies After initial H&P, ECG and neuroimaging CT for a TIA or TSI, what is a “complete Still most common test performed etiologic workup”? Not as sensitive as DWI MRI or MRI CTA Echocardiography An adjunctive test Vessel imaging (CTA, doppler) Evaluates both intracranial and extracranial vasculature The issue is… WHEN do we need to do this workup? TIA: Neuroimaging TIA: Neuroimaging “Results of neuroimaging combined with So… can we wait a week to do a workup risk stratification may help determine in some patients? actual 7-day risk of stroke” Au contraire… Risk ranges from 0.4% to 15% 0.4% - No mimic, negative ECG, DWI MRI without evidence of lesion, ABCD2 < 4 15% - No mimic, negative ECG, DWI MRI with evidence of lesion, ABCD2 > 4 5
TIA Risk Stratification Tools Risk of stroke is highest in the first 48 ABCD2-MRI, CIP, ABCD2-I, ABCD3-I, hours after TIA (and TSI?) ABCDE+, RRE… seriously? Still difficult to differentiate which patients Simplest and most studied is ABCD2 score fall into this group despite multiple risk stratification schemes “ABCD2” Score “ABCD2” Score Criteria Points Risk of stroke A Age ≥ 60 years 1 Validated in 4809 patients (previous data) B SBP > 140 and/or DBP > 90 1 (presentation) C Clinical features 1-2 Score 7-day 90-day Unilateral weakness = 2 points 6-7 11% 18% Speech impairment only = 1 point 4-5 6% 10% D Duration 1-2 ≥ 60 minutes = 2 points 0-3 1.2% 3% 10-59 minutes = 1 point D History of diabetes 1 “ABCD2” Score TIA Disposition and Workup 2 day risk of stroke Hence the recommendation (Class II) Validated in 4809 patients (previous data) “Complete etiologic workup within 48 hours” Score 2-day risk % of pts 6-7 8% 21% 4-5 4% 45% 0-3 1% 34% 6
TIA TIA: Treatment So… because Risk of stroke is highest in the first 48 hours after TIA (and TSI?) Difficult to differentiate which patients fall into this group despite multiple risk stratification schemes Recommendation is to get studies to determine possible etiology within 48 hours TIA: Treatment basics TIA: Treatment Antiplatelet therapy Head of bed flat Blood pressure control Start after CT negative for bleed if no stroke Do not lower BP acutely if under 220/120 mimic Unless hypertensive emergency… e.g. aortic dissection ASA best first choice in ED (CAST trial) Adequate hydration and oxygenation Recommended dose: 50-325 mg/day Antiplatelet therapy Reduces stroke risk Heparin – no (unless cardiogenic source 2.1% to 1.6% suspected) Reduces mortality Endarterectomy 3.9% to 3.3% Only consider with high grade lesions Net benefit: 9 per 1000 treated TIA: Treatment TIA: Treatment Antiplatelet therapy Antiplatelet therapy Other agents / regimens Other agents / regimens Clopidogrel Aspirin PLUS clopidogrel? Aspirin/dipyridamole combination (FASTER study) Both are effective Not superior to aspirin alone Increased risk of bleeding Increased risk of bleeding but small Do NOT combine Consider using in patients on aspirin and still having symptoms (consultation?) 7
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