Transesophageal Echocardiography

Transesophageal Echocardiography - Echo Essentials

• Principles: Utilizes high-frequency ultrasound waves reflecting off cardiac structures. Doppler effect ($Δf = 2 \cdot f_0 \cdot v \cdot \cos(θ) / c$) assesses blood flow. Multiplane probes manipulated by ante/retroflexion, L/R flexion, rotation, advance/withdraw.
• Key Indications: Intraoperative monitoring (cardiac surgery, high-risk non-cardiac), unexplained hemodynamic instability, guiding cardiac procedures (e.g., valve repair, septal defect closure), critical care (ICU).
• Contraindications:

  Absolute	Relative
  Esophageal stricture/tumor, active UGI bleed	Esophageal varices/diverticula, recent UGI surgery
  Perforated viscus	Radiation esophagitis, coagulopathy

• Complications: Most common: sore throat, dysphagia. Serious: Esophageal perforation (risk 0.01-0.09%), dental injury, major bleeding.

  ⭐ Esophageal perforation is the most feared, though rare, complication of TEE. ​

Transesophageal Echocardiography - Window Shopping Heart

TEE offers a crucial intraoperative "window" to cardiac structures and function. Standardized acquisition involves up to 28 views (ASE/SCA guidelines).

Key TEE View Groups:

⭐ The midesophageal four-chamber (ME 4C) view is a cornerstone for assessing global cardiac function, chamber sizes, and atrioventricular valve function.

Transesophageal Echocardiography - Heart's Vital Signs

Key TEE metrics:

• LV Systolic: EF >55%; FAC >35%.
• RV Systolic: TAPSE >17mm; S' (tricuspid annular velocity) >9.5 cm/s.
• Diastolic: E/A ratio; E/e' (septal <15, lateral <10 for normal LVFP); Deceleration Time (DT).
• Stenosis:
  • Gradients: $ΔP = 4v^2$ (Bernoulli).
  • Aortic Valve Area (AVA): $AVA = (CSA_{LVOT} \times VTI_{LVOT}) / VTI_{Valve}$. Severe AS: AVA <1.0 cm².
  • Mitral Valve Area (MVA): $MVA = 220 / PHT$. Severe MS: MVA <1.0 cm².
• Regurgitation:
  • Color Doppler (jet characteristics).
  • Vena Contracta (VC): Severe MR VC >0.7 cm.
  • PISA: Severe MR EROA ≥0.4 cm², Regurgitant Volume (RegVol) ≥60 mL.
• Preload: Left Ventricular End-Diastolic Area (LVEDA)/Right Ventricular End-Diastolic Area (RVEDA); IVC diameter & collapsibility.

Table: Mitral Regurgitation (MR) Severity Grading

⭐ The continuity equation is fundamental for quantifying aortic stenosis severity using TEE, especially when Doppler alignment for direct velocity measurement is challenging.

Transesophageal Echocardiography - Echo in Action

• Intraoperative Monitoring:
  • Ischemia: New Regional Wall Motion Abnormalities (RWMA).
  • Valvular surgery: Assess repair/replacement (e.g., residual MR, Paravalvular Leak (PVL)).
  • Detects air embolism, cardiac masses.
• Critical Care (ICU):
  • Unexplained hypotension/shock: Evaluates LV/RV function, volume status.
  • Suspected PE: RV strain, McConnell's sign.
  • Endocarditis: Vegetations, abscess.
  • Pericardial effusion/tamponade.
  • Guides interventions: pericardiocentesis, vasopressor titration.

⭐ TEE is highly sensitive for detecting new regional wall motion abnormalities, a key indicator of intraoperative myocardial ischemia, often before ECG changes occur.

High‑Yield Points - ⚡ Biggest Takeaways

• TEE is vital for intraoperative cardiac assessment during surgery and for managing hemodynamic instability.
• Evaluates ventricular function (RWMA), valvular diseases, intracardiac air, and aortic pathology.
• Esophageal strictures, tumors, or active bleeding are key contraindications.
• Offers superior views of posterior structures like the mitral valve and descending aorta compared to TTE.
• Critical for guiding CPB cannulation, diagnosing tamponade, and assessing valve repairs.
• Rare but serious complications include esophageal perforation and dental injury.