ISCHEMIC STROKE

Transient ischemic attack (TIA)

David Goldemund M.D.
Updated on 23/09/2024, published on 29/12/2023

2021 ESO guidelines on the management of transient ischemic attack (TIA)

  • Transient Ischemic Attack (TIA) is a medical emergency
  • despite its seemingly mild course, TIA is a serious predictor of subsequent ischemic stroke and death
    • following TIA, the risk of recurrent stroke is 8% in the first week, 11.5% at 1 month, and 17.3% at 3 months    [Coull, 2004]
  • true incidence and prevalence of TIA are challenging to determine because of inconsistent criteria
    • the reported crude annual incidence rate of TIA was 35.2 per 100 000 (95% CI, 30.6–40.3); TIAs are rare in young adults (<45 years) and relatively rare in individuals aged 45–64 years; the incidence then rises steeply, peaking in individuals aged ≥ 85 years  [Degan, 2017]
  • evaluation of TIA and initiation of multimodal therapeutic interventions should be urgent to reduce the risk of subsequent stroke
    • especially TIA within 24 to 48 hours should be managed as stroke
Recurrent stroke risk after transient ischemic attack (TIA) and minor stroke (Coull, 2004)

TIA definition

  • the former definition of TIA (sudden focal neurological deficit lasting < 24 hours of presumed vascular origin) has become obsolete
    • ~ 30-50% of patients defined by such criteria have infarct lesions on DWI  [Oppenheim, 2004]
    • the likelihood of a DWI lesion increases with the duration of symptoms; DWI is positive in over 60% of TIAs lasting > 30 minutes  [Inatomi, 2004]
New TIA definition [Albers, 2002]
Transient episode of neurologic dysfunction due to the focal brain, spinal cord, or retinal ischemia, usually lasting < 1 hour, without acute infarction or tissue injury.

TIA or stroke?

  • TIA – characterized by a short duration of symptoms (usually minutes) with complete resolution of symptoms and negative DWI
  • stroke – indicated by an infarct lesion on imaging and/or persistent clinical symptoms lasting > 24 hours

    • symptomatic stroke (defined by evidence of brain, spinal cord, or retinal injury)
      • persistent symptoms (stroke is diagnosed even if imaging is negative; other etiologies must be ruled out)
      • transient symptoms with positive DWI
    • clinically asymptomatic stroke (incidental finding on imaging)  Asymptomatic DWI lesion
Male 75 years with short lasting mild rightsided hemiparesis. According to new definition it is a stroke with transient symptoms , not TIA

Etiology

Clinical presentation

  • TIA symptoms occur suddenly
  • TIAs typically last only a few minutes, with complete resolution of symptoms and signs
  • the signs and symptoms of a TIA are similar to those of a stroke:
    • hemiparesis or quadruparesis
    • hemihypesthesia
    • speech disorders
      • aphasia
      • slurred speech (dysarthria)
    • visual disturbances
      • blindness in one or both eyes, visual field deficits
      • double vision
    • vestibular syndrome
    • cerebellar syndrome (characterized  by ataxia, dysmetria)
  • global symptoms (lightheadedness, isolated delirium, syncope) and positive symptoms (scintillations) are not typically associated with TIA

Diagnostic evaluation

  • TIAs very often occur hours or days before a stroke; serving as both a warning sign and an opportunity for stroke prevention
  • prompt evaluation and identification of treatable conditions are essential
    • evaluation by a specialist within 24 hours of symptom onset is recommended (ESO guidelines 2021)
    • review in a TIA clinic or admission to a stroke unit are reasonable options (depending on local resources and patient preference)
  • the main goals of TIA evaluation:
    • confirm the vascular origin of the symptoms and exclude non-ischemic causes
      • neurological examination is usually normal at the time of presentation, and thus, a detailed history of symptoms is essential (may help to diagnose TIA or even its etiology)
      • uniform, repeated attacks indicate either pathology at the level of a peripheral branch or perforator or stroke mimics (such as migraine, etc.)
    • determine the underlying mechanism for selecting optimal therapy
      • exclude significant carotid stenosis and major cardioembolic sources (especially atrial fibrillation)
      • palpitations, arrhythmias, and valvular defects, together with symptoms and signs from multiple territories, suggest a cardiac etiology (TOAST 2)

Who should be hospitalized?

  • high-risk patients should either be hospitalized or managed via a specialized TIA clinic
    • the best healthcare setting for treating TIA is still a subject of ongoing research
  • the decision to hospitalize the patient depends on several factors:
    • time elapsed since the last TIA
    • rapid availability of necessary diagnostic tests on an outpatient basis
    • ABCD2 score + clinical judgment + imaging findings  (ideally CT+CTA or DWI+MRA, neurosonology)
      • recent ESO guidelines suggest that predictive tools should not be used alone to identify high-risk patients and to make decisions about triage and treatment (ESO guidelines 2021)
      • a low ABCD2 score should not be a reason to delay diagnostic evaluation and treatment (as individuals with an ABCD2 score ≤ 3 can still be at significant risk of recurrent stroke and require early evaluation and treatment
  • ideally, all patients with TIA should be hospitalized within 24-48 hours to ensure rapid diagnostic evaluation and initiation of therapy
  • novel ABCD3-I  score further improves the detection of high-risk patients  [Song, 2013]
    • this score includes the elements of repeated TIA (Dual TIA) and imaging findings (I-Imaging – DWI, ICA stenosis > 50%) – each scored with 2 points, with a maximum score of 14 points

Acute evaluation of TIA patient

  • focused history
    • onset, duration, timing, symptom specification, any aggravating or relieving factors
    • risk factors and comorbidities (CAD or PAD, smoking, drug abuse, obesity, diabetes, dyslipidemia, and hypertension)
  • clinical examination
    • assess neurological deficits, including speech disturbances, visual field defects, etc. (→ NIHSS)
    • perform a cardiac examination
    • carotid auscultation to detect carotid bruit
  • brain imaging (preferred modality is DWI within 24 hours or CT+CTP  if DWI cannot be performed) (ESO 2021)  (AHA/ASA 2013 I/B)
    • DWI is more sensitive than CT for detecting small infarcts
  • vascular examination – neurosonology  or  CTA/MRA (urgent in recent TIA cases) ( AHA/ASA guidelines 2013 I/A)
    • ESO guidelines 2021 suggest MRA/CTA for confirming large artery stenosis ≥ 50% detected by ultrasound to guide further management
    • strength of MRA compared to ultrasound and CTA is its relative insensitivity to arterial calcifications
  • blood tests
    • complete blood count (CBC) + coagulation tests + ESR
    • basic metabolic panel
    • lipid panel
    • diabetes screening tests
    • urine drug screening in selected cases
  •  electrocardiogram (ECG)
    • standard ECG (AFib?)
    • continue with Holter ECG or prolonged ECG monitoring for at least three weeks (loop recorder)
    • prolonged cardiac rhythm monitoring is reasonable, especially in patients with cortical infarcts with no clear source, to exclude paroxysmal AFib
  • TTE (transthoracic echocardiogram) + TEE (transesophageal echocardiogram)
    • search for PFO, valvular disorder, and other intracardial abnormities
    • assess aortic plaques
  • EEG in DDx of stroke mimics

Differential diagnosis

  • differentiate TIA from stroke mimics (on-vascular conditions presenting with symptoms similar to those of stroke)

Therapy and prevention

  • immediately start multimodal therapeutic intervention
  • treatment may substantially reduce the risk of recurrent stroke or TIA (by 80%) – EXPRESS trial
    • same-day assessment and initiation of standard risk-modification measures following a TIA decreased the 90-day risk of stroke from 10.3 to 2.1%, compared with delayed (or routine) outpatient evaluation and treatment
    • importantly, early treatment did not increase the risk of intracerebral hemorrhage or other bleeding

Antithrombotic therapy

  • antiplatelet drugs (aspirin, clopidogrel, ticagrelor)
    • for patients with an ABCD2 score ≥ 4 prefer short-term (21 days) dual antiplatelet therapy (ASA + clopidogrel), subsequently followed by monotherapy  (ESO guidelines 2021)
    • DAPT with ASA + ticagrelor may be considered as an alternative regimen in patients for whom clopidogrel and aspirin are not an option. This is particularly recommended for those with an ABCD2 score of ≥ 6 or symptomatic intracranial or extracranial arterial stenosis (≥ 50%), according to the THALES trial criteria used to define high-risk TIA
    •  use monotherapy for low-risk TIA or in cases where the TIA diagnosis is uncertain
  • anticoagulation is indicated for patients with AFib or other major sources of cardioembolism)

Surgery and endovascular procedures

  • carotid endarterectomy (CEA) should be performed within 2-14 days if significant carotid stenosis is detected

    • ultra-early preventive CEA (performed <2 days from symptom onset) appears to be associated with a higher perioperative risk of stroke
    • a slight delay may allow the onset of antiplatelet and statin therapy effects, leading to the stabilization of carotid plaque  ⇒  ↓ risks associated with CEA  [Kennedy, 2012]
  • carotid angioplasty with stenting (CAS) – an alternative to CEA
  • intracranial stenoses should be treated with the best medical therapy
    • as the SAMMPRIS trial showed that endovascular stenting is not superior to aggressive medical therapy alone

Vascular risk factors management and others

  • start aggressive blood pressure treatment (⇒ target BP < 130/80 mm Hg, with ACE inhibitors being the preferred medication)   → acute blood pressure management
  • treat dyslipidemia and manage other vascular risk factors
  • consider specific treatment of certain underlying etiologies (vasculitis, etc.)
  • even TIA patients can develop post-traumatic stress disorder (PTSD) with depression or anxiety  (Kiphuth, 2014]
    • teach patients adaptive coping skills and carefully explain the realistic risk of stroke associated with TIA
    • use anxiolytics or antidepressants if necessary

FAQs

What is a Transient Ischemic Attack (TIA)?

  • TIA is defined as a transient episode of neurologic dysfunction due to the focal brain, spinal cord, or retinal ischemia, usually lasting < 1 hour, without acute infarction or tissue injury

What are the common symptoms of a TIA?

  • the symptoms of a TIA are similar to those of a stroke and may include sudden hemiparesis or quadruparesis, hemihypesthesia, speech disorders (aphasia, dysarthria), visual disturbances, vestibular and cerebellar symptoms, etc.

How is a TIA diagnosed?

  • a TIA is diagnosed based on medical history, a neurological exam (symptoms must resolve within 24 hours), and negative brain imaging (CT/MRI shows no signs of relevant permanent brain damage)

What is the difference between a TIA and a stroke?

  • the symptoms of a TIA are temporary and do not cause permanent brain damage, while a stroke causes permanent damage to the brain

How is a TIA treated?

  • managing risk factors such as hypertension, diabetes, and high cholesterol, along with a healthy lifestyle ( a healthy diet, regular exercise, quitting smoking), can significantly reduce the risk of TIA

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