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***LISTEN TO THE PODCAST HERE***

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Epidemiology

• Estimated to be 50-80 per 100,000, or 240,000 per year

Definition

• Original
  • Neurologic deficits lasting for < 24 hours
    • Can still have permanent tissue injury

• Consensus from American Heart Association and American Stroke Association
  • Transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia WITHOUT acute infarction
  • Benefits
    • Tissue damage can be seen on imaging (more objective)
      • Thus, encourages early neurodiagnostic tests

Pathophysiology

• 3 main causes
  • Intrinsic, vessel abnormality
    • Atherosclerosis, lipohyalinosis, dissection, malformation, inflammation
  • Embolic from distal source
  • Inadequate cerebral blood flow
    • Decreased perfusion pressure or increased blood viscosity

Classifications

• 3 main types
  • Large artery, low-flow
    • Brief (minutes to a few hours), recurrent, and sterotyped due to specific vessel it effects
      • Often due to stenotic internal carotid, middle cerebral, or vertebral-basilar junction
  • Embolic
    • Discrete, infrequent, prolonged (several hours) episode
  • Lacunar, small vessel
    • Stenosis of intracerebral penetrating vessels from middle cerebral, basilar, or vertebral arteries
    • HTN and DMII main culprits

Signs and Symptoms

• All depends on the vessels being effected
• 2 Global Regions
  • Anterior Circulation
    • Internal carotid arteries
      • Anterior cerebral artery (contralateral LE>UE weakness)
      • Middle cerebral artery (contralateral face/UE>LE)
  • Posterior Circulation
    • Vertebral arteries
      • Basilar artery (crossed deficits, ataxis, visual disturbances)
        • Cerebellar arteries (dizziness, N/V, visual disturbances)
      • Posterior cerebral artery (visual disturbances, contralateral hemiplegia)

• Disabling symptoms that suggest stroke
  • Complete hemianopsia
  • Severe aphasia
  • Visual/sensory extinction
  • Any weakness limiting sustained effort against gravity
  • NIHSS ≥ 5
  • Inability to walk
  • Modified Rankin Score ≥ 1
  • Any deficit considered potentially disabling to patient or family

Stroke Mimics

• Seizures
• Migraine auras
• Syncope
• Peripheral vestibulopathies
• Pressure/position related peripheral neuropathies
• Metabolic derangements
  • Hypo/hyperglycemia, renal, liver, pulmonary

Initial Evaluation

• Laboratory studies
  • BMP, CBC, NH4, LFT, PT/PTT/INR
• EKG
• Brain imaging
  • Preferred – Brain MRI with diffusion-weighted imaging
  • Suboptimal – Non-contrast head CT
  • CT perfusion scans becoming an option

ABCD² Score

• Used to estimate the risk of ischemic stroke in the first 48 hours after TIA
• 2-day stroke risk
  • 0-3 – 1%
  • 4-5 – 4%
  • ≥ 6 – 8%

Admit or Outpatient???

• Recommend admission for:
  • ABCD² ≥ 3
  • ABCD² ≤ 2 and unsure if work-up can be completed in 48 hours as outpatient
  • ABCD² ≤ 2 and other evidence that this is caused by focal ischemia

Definitive Work-Up

• Neuroimaging within 24 hours of symptom onset
  • Brain MRI with diffusion-weight imaging
• Neurovascular evaluation
  • Preferred – 4-vessel catheter angiography
  • Options – CTA, MRA, CDUS, TCD
• Cardiac Evaluation
  • Reasonable to perform if neurovascular work-up is negative
  • TTE if:
    • Patient ≥ 45 years
    • High suspicion of left ventricular thrombus
    • TEE is contraindicated
  • TEE preferred if:
    • Patient < 45 years without history of CVD
    • Patients with atrial fibrillation
    • Patients with mechanical valve
    • Patients with suspected aortic pathology
    • High pretest probability of cardiac embolic source

Secondary Stroke Prevention

• Medical Management
  • Hypertension
  • Antiplatelet (ASA and clopidogrel)
  • Statins (intensive therapy)
  • Lifestyle modifications
• Large artery disease
  • Carotid
    • Revascularization
      • Endarterectomy
      • Stenting
  • Extracranial vertebral
    • Angioplasty and stenting
  • Intracranial cerebral vessels
    • Intensive medical management
• Small artery disease
  • Intensive medical management
• Cardiogenic embolism
  • Atrial fibrillation
    • Lifelong anticoagulation
  • Myocardial infarction and left ventricular thrombus
    • Anticoagulation for at least 3 months
  • Mitral valve disease (prolapse, calcification)
    • Antiplatelet

Recent Study (video explanation)

One-Year Risk of Stroke after Transient Ischemic Attack or Minor Stroke (TIA Registry Investigators)

• 4789 patients, 61 sites in 21 countries
• Patients
  • ≥ 18 years and had a TIA or minor stroke in the last 7 days
    • Mean age – 66years
    • 70% had HTN and DM
    • 87% sought attention within 24 hours
  • Modified Rankin scale ≤ 1
• Timeline
  • 2-day, 7-day, 30-day, 90-day, and 1-year (following for 5-years)
  • Followed median 27.2 months
• Outcomes
  • Primary (composite)
    • Death from CV causes
    • Nonfatal stroke
    • Nonfatal ACS
  • Secondary
    • Individual components of primary
    • TIA recurrence
    • Death from any cause
    • Bleeding
• Results
  • Primary
    • 2% incidence of major fatal or nonfatal CV events
    • Estimate of stroke risk was 5.1%
      • Highest in 1st 90-days
  • Patients with ABCD² score ≤ 3 still had a 20% early recurrent stroke
  • Higher ABCD² score, large artery atherosclerosis, and multiple infarctions on imaging are strong independent predictors of recurrent events
  • Risk of recurrent stroke was less than half of expected historical cohorts
    • Attributed to faster and more aggressive secondary prevention

Cottage Physician

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References

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2. Easton JD, Saver JL, Albers GW, et al. Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists. Stroke. 2009;40(6):2276-93.
3. Furie KL, Ay H. Initial evaluation and management of transient ischemic attacks and minor ischemic stroke.  In: UpToDate.  Waltham, MA.
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9. Johnston SC, Nguyen-huynh MN, Schwarz ME, et al. National Stroke Association guidelines for the management of transient ischemic attacks. Ann Neurol. 2006;60(3):301-13.
10. Kernan WN, Ovbiagele B, Black HR, et al. Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2014;45(7):2160-236.
11. Whitlock RP, Sun JC, Fremes SE, Rubens FD, Teoh KH. Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):e576S-600S.
12. Amarenco P, Lavallée PC, Labreuche J, et al. One-Year Risk of Stroke after Transient Ischemic Attack or Minor Stroke. N Engl J Med. 2016;374(16):1533-42.