What question did this study set out to answer?

To examine the relationship between left atrial volume indexed to height squared versus body surface area and left atrial function in patients with moderate to severe obesity.

October 26, 2023The International Journal of Cardiovascular ImagingOpen Access

Improved identification of left atrial enlargement in patients with obesity

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Why the study?

Accurate standardization of left atrium volume in patients with obesity is challenging, prompting evaluation of indexing to height2 versus body surface area and its relation to left atrial function.

Does indexing left atrial volume to height² improve the identification of left atrial dysfunction compared to indexing to BSA in patients with moderate to severe obesity?

Key Points

To examine the relationship between left atrial volume indexed to height squared versus body surface area and left atrial function in patients with moderate to severe obesity.
Analyzed echocardiograms of 142 patients with moderate to severe obesity (body mass index ≥ 35 kg/m²) and no known cardiac disease.
Indexed left atrial volume to body surface area (LAE_BSA) and height squared (LAE_h2).
Evaluated left atrial reservoir, conduit, and contractile strain using speckle tracking echocardiography, defining dysfunction as contractile strain < 14%.
Left atrial enlargement was diagnosed in 54.2% of patients using height-squared indexing compared with 18.3% using body surface area indexing.
Patients with height-squared-defined enlargement demonstrated significantly lower contractile strain than those without (12.2% ± 3.2% vs. 13.6% ± 4.5%, p = 0.019).
Height-squared indexing accurately identified significantly more patients with left atrial dysfunction than body surface area indexing (41.5% vs. 15.0%, p < 0.001).

Structured PICO

Does indexing left atrial volume to height² improve the identification of left atrial dysfunction compared to indexing to BSA in patients with moderate to severe obesity?

Population

142 patients with moderate to severe obesity (BMI ≥ 35 kg/m2) without known cardiac disease

Intervention

Indexing left atrial volume (LAV) to height² (LAEh2)

Comparator

Indexing left atrial volume (LAV) to body surface area (BSA) (LAEbsa)

Outcome

Identification of left atrial dysfunction (defined as LA contractile strain < 14%)surrogate

Indexing left atrial volume to height² rather than body surface area improves the identification of left atrial dysfunction in patients with moderate to severe obesity.

Implication

LAEh2 may detect more LA dysfunction than BSA indexing in obese patients; hypothesis-generating and should not yet change practice.

Abstract

Accurate standardization of left atrium volume (LAV) in patients with obesity is challenging. The aim of this study was to investigate and to examine the relation between LAV indexed to height² and left atrial function in patients with moderate to severe obesity. Echocardiograms of patients with moderate to severe obesity (body mass index (BMI) ≥ 35 kg/m²) without known cardiac disease were analyzed. LAV was indexed to body surface area (BSA) and height², and patients were divided into those with or without left atrial enlargement (LAE) based on normalization using either BSA (LAEbsa) or height² (LAEh2). Using speckle tracking echocardiography, LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct) were assessed as a measure of LA function. LA dysfunction was defined as LASct < 14%. A total of 142 patients were included in the analysis of whom 54.2% had LAEh2 and 18.3% LAEBSA. The LAEh2 group had significantly lower LASct (12.2% ± 3.2% vs. 13.6% ± 4.5%, p = 0.019) as compared to the patients without LAEh2. Significantly more patients with LA dysfunction would be correctly identified by LAEh2 than by LAEBSA (41.5% vs. 15.0%, p < 0.001). In patients with moderate to severe obesity, the use of LAEh2 identified significantly more patients with decreased LA function. LAVh2 should be preferred over LAVBSA in patients with moderate to severe obesity.