What are the ways to quantitatively evaluate left ventricular (LV) function on transesophageal echocardiography (TEE) in adult patients?

Quantitative Assessment of LV Function on TEE

The primary quantitative methods for evaluating LV function on TEE include: ejection fraction (EF) via biplane Simpson's method, 2D volumetric measurements, 3D echocardiography when available, and global longitudinal strain (GLS) by speckle-tracking. 1

Core Quantitative Parameters

1. Left Ventricular Ejection Fraction (LVEF)

• Biplane Simpson's method of disks is the recommended 2D technique for calculating LVEF on TEE 1
• Requires tracing of endocardial borders in two orthogonal views (typically transgastric two-chamber and long-axis views) 1
• TEE-derived LVEF correlates excellently with transthoracic measurements (r = 0.93) 2
• Important caveat: LVEF may increase by ≥5 ejection fraction units during TEE in >50% of patients with baseline impaired LV function (LVEF <55%), potentially normalizing function in some cases 2

2. LV Volumes (End-Diastolic and End-Systolic)

• 2D volumetric measurements using biplane method of disks summation (modified Simpson's rule) 1
• Measurements should maximize LV areas while avoiding foreshortening 1
• All measurements should be indexed to body surface area (BSA) for comparison across individuals 1
• Critical limitation: TEE cannot replicate the standardized apical views used in transthoracic imaging, leading to potential measurement differences 1

3. Three-Dimensional Echocardiography

• 3D volumetric analysis provides measurements independent of geometric assumptions about LV shape 1
• More accurate and reproducible compared to 2D methods 1
• Gated 3D TEE acquisitions from midesophageal views allow quantitative assessment of LV global and regional function 1
• Requires semiautomated quantification software using mitral annulus and LV apex as landmarks 1
• Limitations: Lower temporal resolution and image quality dependence 1

4. Global Longitudinal Strain (GLS)

• 2D speckle-tracking derived longitudinal strain is angle-independent and has established prognostic value 1
• TEE longitudinal strain shows excellent agreement with transthoracic measurements 3
• 97% of segments can be analyzed for longitudinal strain via transthoracic approach vs 90% via TEE 3
• Both TEE and transthoracic GLS correlate excellently with LVEF and wall motion score index 3
• Vendor-dependent technology 1

5. Regional Wall Motion Assessment

• Qualitative and semi-quantitative evaluation of segmental wall motion abnormalities 1, 4
• TEE allows assessment in 81% of cases for regional LV wall motion abnormalities when performed by trained operators 4
• Wall motion score index can be calculated and correlates with strain measurements 3

Additional Quantitative Measures

Linear Dimensions

• Not recommended as primary method for TEE due to inability to obtain standardized parasternal views 1
• Teichholz and Quinones methods for calculating volumes from linear dimensions are no longer recommended 1

Fractional Area Change

• Can be calculated from single short-axis cross-sectional images at mid-papillary level 5
• Ejection fraction area (EFa) = (EDa - ESa)/EDa correlates well with scintigraphic EF (r = 0.82) 5
• Limitation: Single cross-sectional area provides reasonable EF estimate but poor correlation with LV end-diastolic volume index 5

Circumferential and Radial Strain

• Can be measured via 2D speckle-tracking on TEE 3
• Circumferential strain shows modest agreement between TEE and transthoracic approaches 3
• Radial strain shows notable disparity between TEE and transthoracic measurements and is less reliable 3

Technical Considerations

Measurement Protocol

• Average measurements over 3 cardiac cycles in sinus rhythm or minimum 5 cycles in atrial fibrillation 1
• Use contrast enhancement when ≥2 contiguous endocardial segments are poorly visualized 1
• Contrast-enhanced images provide volumes closer to cardiac MRI values 1

Common Pitfalls

• Foreshortening of the LV leads to volume underestimation—maximize LV areas in acquired views 1
• TEE probe manipulation may transiently improve LV function in patients with baseline dysfunction 2
• Reference values from awake subjects may not apply—LV dimensions are lower under general anesthesia, though global function indices remain similar 6
• Analysis time for 2D strain is longer with TEE (19±2 min) compared to transthoracic (16±1 min) 3