PhD student University of Bristol Bristol, England, United Kingdom
Abstract:
Background: Myxomatous mitral valve disease (MMVD) is the commonest heart disease in dogs. The left ventricular early inflow-outflow index (LVEIO) is a Doppler estimate of mitral regurgitation severity, validated in human patients. The calculation includes aortic velocity time integral (VTI) measurements, which are affected by cardiac geometry. Geometric differences exist in the hearts of Cavalier King Charles spaniels (CKCS) compared to other breeds, which might affect LVEIO. Hypothesis/objective: In dogs with stage B1 MMVD, LVEIO is higher in CKCS compared to non-CKCS. Animals: 34 privately owned dogs with stage B1 MMVD (21 CKCS and 13 non-CKCS) enrolled in a longitudinal study of MMVD.
Methods: Retrospective cross-sectional study. Stage B1 MMVD was diagnosed as per ACVIM consensus statement. LVEIO was calculated as the ratio between mitral inflow E wave maximum velocity and aortic VTI. Data distribution was tested using the Shapiro-Wilk test. Correlations were tested using Pearson’s or Spearman’s ρ test. Groups (CKCS vs non-CKCS) were compared using unpaired Student’s t-test or Mann-Whitney tests as appropriate. Data are reported as median (minimum-maximum).
Results: E wave velocity (p=0.69) and aortic VTI (p=0.055) were not different between groups (Figure 1). There was no correlation between LVEIO and body weight in CKCS (p=0.35, ρ=-0.22) or non-CKCS (p=0.49, ρ=-0.21). LVEIO was significantly higher in CKCS (5.42 (3.06-7.98)) vs non-CKCS dogs (4.67 (3.04-11.45); p=0.029). Conclusions and clinical importance: LVEIO can be easily obtained and might provide further information about MMVD severity in dogs. However, a breed-specific range for CKCS should be considered for more accurate assessment.
