Echocardiography in Stroke Workup

Echocardiography remains a cornerstone of stroke evaluation, helping identify cardioembolic sources that fundamentally change management. For the vascular neurologist, understanding when to order TTE versus TEE, recognizing high-risk findings, and integrating echo data with other cardiac workup modalities is essential for optimizing secondary prevention.

When Does Echo Change Management?

Echocardiography should be ordered when findings could alter treatment decisions. The key question: Will this change anticoagulation, lead to intervention, or reclassify stroke etiology?

Echo Changes Management When It Detects:

  • Intracardiac thrombus → Anticoagulation
  • Vegetation → Antibiotics, possible surgery
  • Severe LV dysfunction (EF <35%) → Anticoagulation consideration, HF management
  • PFO with high-risk features → Closure consideration
  • Valvular heart disease → Surgical evaluation
  • Atrial myxoma or cardiac tumor → Surgical resection
  • Aortic arch atheroma ≥4mm → Aggressive medical therapy, possible anticoagulation

TTE vs TEE: Choosing the Right Study

Feature TTE (Transthoracic) TEE (Transesophageal)
Invasiveness Non-invasive Semi-invasive (sedation, esophageal probe)
Image Quality Variable (body habitus, lung disease) Superior (probe adjacent to heart)
LV Function Excellent Good
LV Thrombus Moderate (70–75% sensitivity) Better, but not gold standard
LA/LAA Thrombus Poor (<50% sensitivity) Excellent (95–100% sensitivity)
PFO Detection Moderate with bubble study Superior (direct visualization)
Atrial Septal Aneurysm Moderate Excellent
Aortic Arch Limited (descending only) Excellent visualization
Vegetations Moderate (especially posterior structures) Excellent (mitral, prosthetic valves)
Prosthetic Valves Limited (acoustic shadowing) Superior
Availability Widely available, portable Requires scheduling, specialized staff
Contraindications None Esophageal pathology, severe coagulopathy

TTE First — Always

TTE should be the initial study for nearly all stroke patients. It provides:

  • LV systolic function (EF) — critical for risk stratification
  • Regional wall motion abnormalities (suggests prior MI, potential for LV thrombus)
  • Valvular disease assessment
  • LA size (dilated LA increases AF risk)
  • Bubble study for PFO screening (if performed with agitated saline)

When to Proceed to TEE

TEE is indicated when TTE is non-diagnostic or when specific high-yield findings are suspected:

📋 TEE Indications in Stroke

  • Cryptogenic stroke — especially if age <60, no vascular risk factors
  • Suspected LAA thrombus — AF patient, pre-cardioversion
  • PFO confirmation — positive bubble study on TTE, planning closure
  • Prosthetic valve evaluation — suspected thrombosis or endocarditis
  • Aortic arch assessment — embolic pattern, no other source
  • Endocarditis workup — negative TTE but high clinical suspicion
  • Poor TTE windows — obese, COPD, ventilated patients

High-Risk vs Low-Risk Echocardiographic Findings

Not all echo abnormalities warrant treatment changes. Understanding the hierarchy of findings helps prioritize management.

High-Risk Findings (Change Management) Low/Uncertain Risk (Usually Don’t Change Rx)
LV/LA/LAA thrombus Mitral annular calcification
Vegetation (infective endocarditis) Aortic valve sclerosis (without stenosis)
Severe LV dysfunction (EF <35%) Mild LV dysfunction (EF 40–50%)
Akinetic/dyskinetic LV segment (post-MI) Mild LA enlargement
PFO + atrial septal aneurysm Small PFO without ASA
Large PFO with significant shunt Lipomatous hypertrophy of interatrial septum
Mobile aortic arch atheroma ≥4mm Aortic atheroma <4mm
Atrial myxoma Lambl’s excrescences
Mechanical prosthetic valve Bioprosthetic valve (without thrombus)
Rheumatic mitral stenosis Mild mitral regurgitation

Intracardiac Thrombus Detection

Thrombus is the “smoking gun” for cardioembolic stroke and mandates anticoagulation. However, detection sensitivity varies significantly by location and imaging modality.

LV Thrombus

  • Typically forms in areas of akinesis/dyskinesis (anterior MI, dilated cardiomyopathy)
  • TTE sensitivity: 70–75% (improves with contrast)
  • Contrast-enhanced TTE: 90–95% sensitivity
  • Cardiac MRI: Gold standard (approaching 100%)
  • Cardiac CT: 88–95% sensitivity (emerging role)

LA/LAA Thrombus

  • Most commonly associated with atrial fibrillation
  • TTE sensitivity: Very poor (<50% for LAA)
  • TEE sensitivity: 95–100% (gold standard)
  • Cardiac CT: 96–100% sensitivity with optimized protocols

Emerging Data: Cardiac CT Outperforms TTE

Recent studies demonstrate that extended cardiac CT protocols detect thrombi missed by TTE:

Cardiac CT vs TTE Study (2022):

  • High-risk embolic sources: 11.4% CT vs 4.9% TTE (OR 5.60)
  • Thrombus detection: 7.1% CT vs 0.6% TTE
  • CT altered management in multiple cases

ESUS Thrombus Detection:

  • CCTA can detect intracardiac thrombus in a minority of ESUS patients in selected series
  • Thrombi were NOT seen on TTE but visualized on CT
  • 21% of patients had anticoagulation newly indicated

⚡ Clinical Pearl

TTE misses a significant proportion of intracardiac thrombi. In cryptogenic stroke, consider cardiac CT or TEE rather than accepting a “negative TTE” as ruling out thrombus—especially if anterior wall motion abnormality or AF is present.

PFO Assessment

Patent foramen ovale is present in ~25% of the general population but found in up to 40–50% of cryptogenic stroke patients. The clinical challenge is determining when a PFO is causative versus incidental.

Bubble Study Technique

Agitated saline contrast (“bubble study”) is essential for PFO detection:

  1. Inject agitated saline IV (typically via antecubital vein)
  2. Observe right heart opacification with microbubbles
  3. Perform Valsalva maneuver (or cough, or abdominal compression)
  4. Positive = bubbles appear in LA within 3–5 cardiac cycles
  5. >5 cycles suggests pulmonary AVM rather than PFO

Shunt Grading

Grade Microbubbles in LA Clinical Significance
0 (Negative) None No shunt
1 (Small) 1–10 Small PFO; lower stroke risk
2 (Moderate) 11–30 Moderate PFO
3 (Large) >30 or complete LA opacification Large shunt; higher stroke risk; closure benefit strongest

High-Risk PFO Features

These features increase the likelihood that a PFO is stroke-related and identify patients who benefit most from closure:

  • Large shunt (Grade 3, >30 bubbles)
  • Atrial septal aneurysm (ASA) — excursion ≥10mm beyond septal plane
  • Hypermobile septum — total excursion ≥15mm
  • Eustachian valve or Chiari network — directs flow toward PFO
  • Spontaneous right-to-left shunting (without Valsalva)
  • Long PFO tunnel — greater stasis, thrombus risk

The RoPE Score

The Risk of Paradoxical Embolism (RoPE) Score estimates the probability that a detected PFO is stroke-related versus incidental:

Characteristic Points
No history of hypertension +1
No history of diabetes +1
No history of stroke or TIA +1
Non-smoker +1
Cortical infarct on imaging +1
Age 18–29 +5
Age 30–39 +4
Age 40–49 +3
Age 50–59 +2
Age 60–69 +1
Age ≥70 0

RoPE Score Interpretation

RoPE Score PFO-Attributable Fraction Interpretation
0–3 0–20% PFO likely incidental; closure unlikely to help
4–5 20–40% Uncertain; consider other factors
6–7 50–70% PFO likely causative; closure reasonable
8–10 80–90% PFO very likely causative; strong closure indication

✓ Who Benefits from PFO Closure?

Based on CLOSE, RESPECT, and REDUCE trials, closure is most beneficial in patients with:

• Age <60 with cryptogenic stroke
• Large shunt (Grade 3) OR atrial septal aneurysm
• Compatible clinical profile (a high RoPE score supports PFO attribution, though the closure RCTs did not select by RoPE)
• No competing stroke etiology identified

Left Ventricular Dysfunction and Wall Motion

LV dysfunction increases stroke risk through multiple mechanisms: stasis leading to thrombus, associated AF, and endothelial dysfunction.

When LV Dysfunction Matters

  • EF <35% (sinus rhythm): routine anticoagulation is not supported—WARCEF and COMMANDER-HF showed no net benefit (less ischemic stroke offset by more bleeding); anticoagulate only for documented thrombus or AF
  • EF 35–50%: Optimize HF therapy; anticoagulation not routinely indicated
  • Akinetic/dyskinetic segments: Higher thrombus risk—order contrast echo or cardiac MRI
  • Recent MI with anterior akinesis: ~15% develop LV thrombus; consider prophylactic anticoagulation

Regional Wall Motion Abnormalities (RWMA)

RWMA suggests prior MI or stress cardiomyopathy and identifies patients at thrombus risk:

  • Anterior/apical akinesis: Highest thrombus risk (apex is most common site)
  • Large akinetic zone: Consider contrast echo to exclude mural thrombus
  • New RWMA + troponin elevation: Evaluate for concurrent ACS

Valvular Heart Disease

Native Valve Disease

  • Rheumatic mitral stenosis: High stroke risk—anticoagulation indicated (even without AF)
  • Mitral valve prolapse: Low stroke risk unless myxomatous degeneration with severe MR
  • Aortic stenosis: Embolic events rare; consider calcific emboli in severe AS
  • Mitral annular calcification: Associated with AF and stroke, but not an indication for anticoagulation alone

Prosthetic Valves

  • Mechanical valves: Require lifelong warfarin (DOACs contraindicated)
  • Bioprosthetic valves: Anticoagulation for 3–6 months post-op, then aspirin
  • TAVR valves: Subclinical leaflet thrombosis increasingly recognized; optimal antithrombotic uncertain

Infective Endocarditis

Vegetation >10mm, mitral involvement, and Staph aureus are high-risk features for embolization.

  • TTE sensitivity: 50–75% for native valves
  • TEE sensitivity: 90–100% (required if TTE negative and suspicion high)
  • Consider TEE for all prosthetic valves with suspected endocarditis

Aortic Arch Atheroma

Complex aortic arch plaque is associated with cryptogenic stroke and recurrent events. TEE is the primary modality (TTE cannot visualize the arch).

Grading System

Grade Description Stroke Risk
I Intimal thickening <2mm Low
II Atheroma <4mm, non-ulcerated Low-Moderate
III Atheroma ≥4mm Moderate-High
IV Mobile or ulcerated plaque High
V Mobile plaque ≥4mm Very High

Management

  • High-intensity statin for all ≥Grade II
  • Antiplatelet therapy (aspirin)
  • Anticoagulation: Controversial; consider for Grade IV–V with recurrent events
  • BP control and smoking cessation

Yield of Echo by Stroke Subtype

Stroke Subtype Expected Echo Yield Recommendation
Known AF Low (etiology established) TTE for LV function; TEE only if pre-cardioversion
Cryptogenic / ESUS Highest yield TTE + bubble; consider TEE or cardiac CT
Large Artery Atherosclerosis Low TTE for baseline LV function
Small Vessel (Lacunar) Very low TTE if concurrent AF risk factors
Young Stroke (<55) Moderate-High (PFO, myxoma) TTE + bubble; TEE if PFO positive
Recurrent Cryptogenic High TEE and/or cardiac CT mandatory

Practical Algorithm

🔄 Echo Workup Algorithm for Ischemic Stroke

Step 1: All patients → TTE with bubble study

Step 2: If TTE shows:

  • LV thrombus → Anticoagulate (consider contrast echo or CMR to confirm)
  • EF <35% → HF therapy; consider anticoagulation
  • Vegetation → Endocarditis workup and treatment
  • Positive bubble → Quantify shunt; assess for ASA

Step 3: Proceed to TEE if:

  • Cryptogenic stroke and age <60
  • PFO positive on TTE—need to confirm and assess for closure
  • Suspected LAA thrombus (AF patient)
  • Suspected endocarditis with negative TTE
  • Prosthetic valve evaluation
  • Aortic arch assessment needed

Alternative to TEE: Cardiac CT (if available) — superior for thrombus detection, non-invasive, can be done during initial stroke imaging

🔹 Bottom Line: Echo in Stroke Workup

  • TTE first — assesses LV function, valves, and PFO (with bubble study)
  • TEE when needed — LAA thrombus, PFO confirmation, aortic arch, endocarditis
  • TTE misses thrombi — cardiac CT detects 7% thrombus vs 0.6% TTE
  • High-risk PFO features — large shunt, ASA, high RoPE score → closure
  • Yield highest in cryptogenic stroke — prioritize comprehensive workup
  • LV dysfunction with akinesis — consider contrast echo or MRI for thrombus

References

  1. Saric M, et al. Guidelines for the use of echocardiography in the evaluation of a cardiac source of embolism. J Am Soc Echocardiogr. 2016;29:1–42.
  2. Kent DM, et al. An index to identify stroke-related vs incidental patent foramen ovale in cryptogenic stroke (RoPE Score). Neurology. 2013;81:619–625.
  3. Saver JL, et al. Long-term outcomes of patent foramen ovale closure or medical therapy after stroke (RESPECT). N Engl J Med. 2017;377:1022–1032.
  4. Mas JL, et al. Patent foramen ovale closure or anticoagulation vs. antiplatelets after stroke (CLOSE). N Engl J Med. 2017;377:1011–1021.
  5. Søndergaard L, et al. Patent foramen ovale closure or antiplatelet therapy for cryptogenic stroke (REDUCE). N Engl J Med. 2017;377:1033–1042.
  6. Grotta JC, et al. Expert consensus on cardiac CT for stroke workup. Stroke. 2022;53:e535–e548.
  7. Yaghi S, et al. Cardioembolic stroke in the era of advanced cardiac imaging. JAMA Neurol. 2022;79:305–314.
  8. Pepi M, et al. Recommendations for echocardiography use in the diagnosis and management of cardiac sources of embolism. Eur Heart J Cardiovasc Imaging. 2021;22:e1–e59.