• Open Access

Discrepancies in Identification of Left Atrial Enlargement Using Left Atrial Volume versus Left Atrial-to-Aortic Root Ratio in Dogs

Authors

  • S. Wesselowski,

    Corresponding author
    1. Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
    • Corresponding author: S. Wesselowski, Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, 205 Duck Pond Drive, Blacksburg, VA 24061; e-mail: sonyarw@vt.edu.

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  • M. Borgarelli,

    1. Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
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  • N.M. Bello,

    1. Department of Statistics, Kansas State University, Manhattan, KS
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  • J. Abbott

    1. Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA
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  • The work was performed at the Veterinary Teaching Hospital at the Virginia-Maryland Regional College of Veterinary Medicine and the Veterinary Teaching Hospital at the Kansas State University College of Veterinary Medicine.
  • The study was presented in abstract form at the 2013 ACVIM Forum, Seattle, WA.

Abstract

Background

Left atrial size is prognostically important in dogs with myxomatous mitral valve disease (MMVD).

Hypothesis/Objectives

To compare the level of agreement in identification of left atrial enlargement (LAE) between the left atrial-to-aortic root ratio (LA : Ao) and left atrial volume using the biplane area-length method indexed to body weight (LA Vol/BW).

Animals

Sixty dogs with MMVD and 22 normal dogs were prospectively studied with 2-dimensional echocardiography.

Methods

The upper limit of normal for LA Vol/BW was defined as 1.1 mL/kg. LA : Ao was deemed normal if ≤1.5. To define overall disease severity, each dog was assigned a mitral regurgitation severity score (MRSS) based on echocardiographic parameters that did not include left atrial size. ACVIM staging also was utilized.

Results

Of 60 affected dogs, 20 were ACVIM Stage B1, 25 were Stage B2, and 15 were Stage C. LA Vol/BW identified LAE in 12 cases in which LA : Ao was normal; 7 of these were Stage B1 and 5 were Stage B2. This diagnostic disagreement was significant (P = .00012). Of the 12 cases in which diagnostic discrepancies were identified, 5/5 of the B2 dogs and 3/7 B1 dogs had a moderate MRSS, whereas 4/7 B1 dogs had a mild MRSS. No diagnostic discrepancies between LA : Ao and LA Vol/BW were apparent in dogs with a severe MRSS.

Conclusions and Clinical Importance

This study shows evidence of diagnostic disagreement between LA : Ao and LA Vol/BW for assessment of LAE. LA Vol/BW may be superior to LA : Ao for identification of mild LAE.

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