Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jan-Feb;38(1):51-60.
doi: 10.1111/jvim.16923. Epub 2023 Nov 1.

Efficacy of a mitral regurgitation severity index to predict long-term outcome in dogs with myxomatous mitral valve disease

Michelle Vereb  1 , Clarke E Atkins  2 , Darcy Adin  3 , Thomas Blondel  4 , Melissa Coffman  5 , Seunggon Lee  6 , Emilie Guillot  4 , Jessica L Ward  1
Affiliations

Efficacy of a mitral regurgitation severity index to predict long-term outcome in dogs with myxomatous mitral valve disease

Michelle Vereb et al. J Vet Intern Med. 2024 Jan-Feb.

Abstract

Background: Predicting progression of myxomatous mitral valve disease (MMVD) in dogs can be challenging.

Hypothesis/objectives: The mitral regurgitation severity index (MRSI) will predict time to congestive heart failure (CHF) and all-cause death in dogs with MMVD.

Animals: Eight hundred sixty-nine client-owned dogs.

Methods: Retrospective study pooling data from 4 previous samples including dogs with MMVD stage B2 or C. MRSI was calculated as: (heart rate [HR]/120) × left atrium-to-aorta ratio (LA:Ao) × (age in years/10) × 100. Alternative MRSI formulas substituting radiographic measures of left atrial size were also calculated. Cox proportional hazard modeling and time-dependent receiver-operator characteristic curves quantified prognostic performance.

Results: For Stage B2 pooled samples, MRSI > 156 was predictive of time to CHF (median 407 vs 1404 days; area under the curve [AUC] 0.68; hazard ratio 3.02 [95% CI 1.9-4.9]; P < .001). MRSI > 173 was predictive of all-cause death (median survival 868 vs 1843 days; AUC 0.64; hazard ratio 4.26 [95% CI 2.4-7.5]; P < .001). MRSI showed superior predictive value compared to the individual variables of HR, LA:Ao, and age. Variations of the MRSI equation substituting radiographic vertebral left atrial size for LA:Ao were also significantly predictive of outcome in stage B2. MRSI was not consistently predictive of outcome in Stage C.

Conclusions and clinical importance: MRSI was predictive of outcome (onset of CHF and all-cause death) in MMVD Stage B2, demonstrating utility as a useful prognostic tool. Echocardiographic LA:Ao can be effectively replaced by radiographically determined LA size in the MRSI formula.

Keywords: congestive heart failure; echocardiography; prognosis; thoracic radiographs; vertebral heart size; vertebral left atrial size.

PubMed Disclaimer

Conflict of interest statement

Drs. Blondel, Coffman, and Guillot are employees of Ceva Santé Animale/Ceva Animal Health. Drs. Atkins, Adin, and Ward have received consulting fees and honoraria from Ceva Santé Animale. As a veterinary pharmaceutical company, Ceva develops and markets cardiovascular medications for dogs with MMVD, and sponsored 1 of the studies for which a dataset was utilized in the present retrospective study. However, the purpose and results of the present retrospective study deal only with prognosis for MMVD, not with the impact or outcome of any specific drug. No other authors declare a conflict of interest.

Figures

FIGURE 1
FIGURE 1
CONSORT diagram describing the 4 study samples, including number of dogs with Stage B2 and Stage C myxomatous mitral valve disease, medication requirements or restrictions, and availability of radiographs for each study sample. ACEi, angiotensin converting enzyme inhibitor; n, number of dogs.
FIGURE 2
FIGURE 2
Kaplan‐Meier curves for 234 dogs with Stage B2 myxomatous mitral valve disease from 3 pooled study samples (S1, n = 45; S2, n = 56; S3, n = 133), depicting the time to (A) congestive heart failure, comparing dogs with a Mitral Regurgitation Severity Index (MRSI) ≤ 156 (red line) vs MRSI > 156 (blue line); and (B) all‐cause death, comparing dogs with MRSI ≤ 173 (red line) vs MRSI > 173 (blue line). P values for MRSI comparisons are shown. Formulas used to calculate MRSI are shown in Table 1.
See this image and copyright information in PMC

References

    1. Borgarelli M, Buchanan JW. Historical review, epidemiology and natural history of degenerative mitral valve disease. J Vet Cardiol. 2012;14:93‐101. - PubMed
    1. Keene BW, Atkins CE, Bonagura JD, et al. ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs. J Vet Intern Med. 2019;33:1127‐1140. - PMC - PubMed
    1. Borgarelli M, Savarino P, Crosara S, et al. Survival characteristics and prognostic variables of dogs with mitral regurgitation attributable to myxomatous valve disease. J Vet Intern Med. 2008;22:120‐128. - PubMed
    1. Borgarelli M, Crosara S, Lamb K, et al. Survival characteristics and prognostic variables of dogs with preclinical chronic degenerative mitral valve disease attributable to myxomatous degeneration. J Vet Intern Med. 2012;26:69‐75. - PubMed
    1. Häggström J, Boswood A, O'Grady M, et al. Effect of pimobendan or benazepril hydrochloride on survival times in dogs with congestive heart failure caused by naturally occurring myxomatous mitral valve disease: the QUEST study. J Vet Intern Med. 2008;22:1124‐1135. - PubMed