Transient Ischemic Attack (TIA)

1️⃣ Definition 

A Transient Ischemic Attack (TIA) is:

A transient episode of focal neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction on imaging.

This is the tissue-based definition (AHA/ASA), which has replaced the old “<24 hours” time-based definition.

• Earlier definition: Symptoms resolving within 24 hours
• Current definition: No infarction on DWI MRI, regardless of duration

Even 5–10 minutes of deficit can represent completed infarction, so imaging is crucial.

2️⃣ Why TIA is a Critical Care Emergency

TIA is not “minor stroke.” It is:

• A warning stroke
• A medical emergency
• A marker of unstable vascular disease

Risk of Stroke After TIA

3️⃣ Pathophysiology

TIA results from temporary cerebral hypoperfusion due to:

A. Embolic Causes

• Cardioembolism (AF most common)
• Carotid plaque emboli
• Aortic arch atheroma

B. Large Artery Atherosclerosis

• Internal carotid stenosis
• Vertebrobasilar disease

C. Small Vessel Disease

• Lacunar TIAs

D. Hemodynamic Causes

• Severe carotid stenosis + hypotension

4️⃣ Clinical Presentation

Symptoms are focal, sudden, and maximal at onset.

🔹 Anterior Circulation TIA

Features:

• Unilateral weakness
• Hemisensory loss
• Aphasia (dominant hemisphere)
• Monocular vision loss (amaurosis fugax)

🔹 Posterior Circulation TIA

Features:

• Diplopia
• Dysarthria
• Ataxia
• Vertigo (with focal signs)
• Bilateral weakness
• Drop attacks

 Isolated vertigo without focal deficit is rarely TIA.

5️⃣ TIA Mimics 

6️⃣ Risk Stratification – ABCD² Score

Max = 7

Interpretation

• 0–3 → Low risk
• 4–5 → Moderate
• 6–7 → High risk
  Modern guidelines do NOT rely solely on ABCD² for admission decisions.
  Imaging and vascular evaluation are mandatory.

7️⃣ Emergency Evaluation (Within 24 Hours)

1. Brain Imaging

Preferred: MRI with DWI

• Detects silent infarction
• Up to 30–50% “TIA” have infarct on MRI

If unavailable → Non-contrast CT (rule out hemorrhage)

2. Vascular Imaging

• Carotid Doppler
• CT angiography
• MR angiography

Goal: Detect ≥50% carotid stenosis

3. Cardiac Evaluation

• ECG
• Continuous telemetry
• Echocardiography
• Holter (if cryptogenic)

Look for:

• Atrial fibrillation
• LV thrombus
• PFO
• Valvular disease

4. Laboratory Work

• CBC
• Glucose
• Lipid profile
• Renal function
• Coagulation profile

8️⃣ Acute Management in ICU / Stroke Unit

A. Antiplatelet Therapy (Non-cardioembolic TIA)

If minor stroke or high-risk TIA (ABCD² ≥4):

Dual Antiplatelet Therapy (DAPT)

• Aspirin + Clopidogrel
• Duration: 21 days (max 90 days in selected)

Evidence: CHANCE & POINT trials

Then → Single antiplatelet lifelong

B. If Cardioembolic (AF Present)

Start anticoagulation:

• DOAC preferred
• Timing:
• TIA → Start within 1–3 days
• Small infarct → 3–5 days

No need for heparin bridging in most cases.

C. Blood Pressure Management

• Do NOT aggressively reduce BP
• Treat only if >220/120 mmHg
• Gradual control over days

D. Statins

High-intensity statin for all atherosclerotic TIA

• LDL target <70 mg/dL (very high risk)

9️⃣ Carotid Revascularization

Indications

Symptomatic carotid stenosis:

Options

• Carotid endarterectomy
• Carotid artery stenting

Endarterectomy preferred in low surgical risk patients.

🔟 Special Situations in CCM

1️⃣ Crescendo TIAs

Multiple TIAs within 24–48h
→ ICU admission
→ Urgent vascular imaging
→ Consider early revascularization

2️⃣ TIA with AF and Hemodynamic Instability

• Control rate
• Evaluate LV function
• Early anticoagulation

3️⃣ Cryptogenic TIA

• Prolonged rhythm monitoring
• PFO evaluation
• Hypercoagulable workup (young patients)

1️⃣1️⃣ Secondary Prevention – Long-Term Strategy

A. Antiplatelet / Anticoagulation

Based on mechanism

B. BP Target

<130/80 mmHg

C. Lipid Target

LDL <70 mg/dL

D. Diabetes Control

HbA1c <7%

E. Lifestyle

• Smoking cessation
• Mediterranean diet
• Exercise 150 min/week

1️⃣2️⃣ Prognosis

TIA is:

• A marker of unstable plaque
• A predictor of future stroke
• A systemic vascular disease indicator

Long-term:

• ↑ risk MI
• ↑ risk vascular death