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 detected intracardiac thrombus in 17% of ESUS patients (10% LV, 6% LAA)
- 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:
- Inject agitated saline IV (typically via antecubital vein)
- Observe right heart opacification with microbubbles
- Perform Valsalva maneuver (or cough, or abdominal compression)
- Positive = bubbles appear in LA within 3–5 cardiac cycles
- >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
• High RoPE score (≥7)
• 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%: Consider anticoagulation (HFrEF trials showed modest benefit)
- 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
- 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.
- 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.
- 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.
- Mas JL, et al. Patent foramen ovale closure or anticoagulation vs. antiplatelets after stroke (CLOSE). N Engl J Med. 2017;377:1011–1021.
- Søndergaard L, et al. Patent foramen ovale closure or antiplatelet therapy for cryptogenic stroke (REDUCE). N Engl J Med. 2017;377:1033–1042.
- Grotta JC, et al. Expert consensus on cardiac CT for stroke workup. Stroke. 2022;53:e535–e548.
- Yaghi S, et al. Cardioembolic stroke in the era of advanced cardiac imaging. JAMA Neurol. 2022;79:305–314.
- 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.