Key result
Mitral-to-aortic VTI ratio accurately identifies severe mitral regurgitation with an AUC of ~0.89.
Why the study?
Quantitative assessment of mitral regurgitation severity in dogs with myxomatous mitral valve disease remains challenging, and the mitral-to-aortic VTI ratio has been proposed as a potential index for severity stratification.
Does the mitral-to-aortic velocity time integral (VTI) ratio accurately correlate with mitral regurgitation severity and congestive heart failure in dogs with myxomatous mitral valve disease?
Cross-Sectional (n=188)
Does the mitral-to-aortic velocity time integral (VTI) ratio accurately correlate with mitral regurgitation severity and congestive heart failure in dogs with myxomatous mitral valve disease?
The mitral-to-aortic VTI ratio is a reproducible Doppler echocardiographic index that strongly correlates with mitral regurgitation severity in dogs with myxomatous mitral valve disease.
Answers are grounded in this paper and cite their sources.
May aid noninvasive grading of severe MR in dogs; extends human VTI ratio data but leaves open outcome validation.
INTRODUCTION/OBJECTIVES: In dogs, myxomatous mitral valve disease is the most commonly acquired cardiac disorder. Quantitative assessment of mitral regurgitation (MR), particularly regurgitant volume normalized to body weight (RVol/kg), remains challenging. A Doppler-derived mitral-to-aortic velocity time integral (VTI) ratio (calculated as mitral inflow VTI) divided by left ventricular outflow tract VTI]) has been proposed in humans to stratify MR severity. This study evaluated its association with MR severity, American College of Veterinary Internal Medicine stage, and congestive heart failure (CHF). ANIMALS, MATERIALS AND METHODS: We evaluated 167 dogs with myxomatous mitral valve disease and 21 controls. Echocardiography included mitral inflow VTI, left ventricular outflow tract VTI, and RVol/kg. Repeatability was assessed using intraclass correlation coefficients. Receiver operating characteristic analysis was used to evaluate performance for detecting CHF and severe MR defined by a regurgitant fraction (RF) ≥50%. RESULTS: The mitral-to-aortic VTI ratio increased with stage (P<0.001) and correlated with RVol/kg and RF (r=0.75 each; P<0.001), with high repeatability (intraclass correlation coefficient >0.90). Multivariable regression identified early diastolic transmitral velocity (E), left atrium-to-aorta ratio, and RVol/kg as independent determinants of the mitral-to-aortic VTI ratio. Logistic regression to detect CHF (current and past) showed the association between the mitral-to-aortic VTI ratio and CHF. In the receiver operating characteristic curve analysis, the mitral-to-aortic VTI ratio showed the highest accuracy for identifying an RF ≥ 50% (area under the curve=0.89). STUDY LIMITATIONS: Few dogs were in stage C/D. CONCLUSIONS: The mitral-to-aortic VTI ratio is a reproducible Doppler index associated with MR severity and American College of Veterinary Internal Medicine stage and may help indicate clinically relevant RF thresholds.
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Kawai et al. (2026) conducted a cross-sectional in Myxomatous mitral valve disease (n=188). Mitral-to-aortic velocity time integral (VTI) ratio vs. Healthy controls or lower disease stages was evaluated on Identifying severe mitral regurgitation (regurgitant fraction ≥ 50%) (AUC 0.89). The mitral-to-aortic VTI ratio accurately identified severe mitral regurgitation (regurgitant fraction ≥50%) with an area under the curve of 0.89.
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