#13 – Transient Ischemic Attacks



 

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
Picture1

Ay H. Ann Neuro. 2005;57(5):679-86

  • 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)
UpToDate

UpToDate

  • 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%
UpToDate

UpToDate

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
UpToDate

UpToDate

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
Amarenco P. NEJM. 2016;374(16):1533-42

Amarenco P. NEJM. 2016;374(16):1533-42

Cottage Physician

Cottage Physician - 1893

Cottage Physician – 1893


References

  1. Go AS, Mozaffarian D, Roger VL, et al. Heart disease and stroke statistics–2014 update: a report from the American Heart Association. Circulation. 2014;129(3):e28-e292.
  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.
  4. Ay H, Koroshetz WJ, Benner T, et al. Transient ischemic attack with infarction: a unique syndrome?. Ann Neurol. 2005;57(5):679-86.
  5. Quinn TJ, Dawson J, Walters MR, Lees KR. Reliability of the modified Rankin Scale: a systematic review. Stroke. 2009;40(10):3393-5.
  6. Levine SR, Khatri P, Broderick JP, et al. Review, historical context, and clarifications of the NINDS rt-PA stroke trials exclusion criteria: Part 1: rapidly improving stroke symptoms. Stroke. 2013;44(9):2500-5.
  7. Brott T, Adams HP, Olinger CP, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989;20(7):864-70.
  8. Johnston SC, Rothwell PM, Nguyen-huynh MN, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007;369(9558):283-92.
  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.

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