Prevalence and prognostic importance of pulmonary hypertension in dogs with myxomatous mitral valve disease.

Abstract

BACKGROUND: Pulmonary hypertension (PH) is common in dogs with myxomatous mitral valve disease (MMVD) but its effect on clinical outcome has not been investigated. HYPOTHESIS/OBJECTIVES: The presence of PH worsens the outcome in dogs with MMVD. To compare survival times of dogs with MMVD and PH to those without PH. ANIMALS: Two hundred and twelve client-owned dogs. METHODS: Case review study. Medical records of dogs diagnosed with ACVIM stage B2 and C MMVD between January 2010 and December 2011 were retrospectively reviewed. Long-term outcome was determined by telephone interview or from the medical record. End of the observation period was March 2013. PH was identified if tricuspid regurgitation peak velocity was >3&#xa0;m/s. RESULTS: Two hundred and twelve were identified. Eighty-three dogs (39%) had PH. PH was more commonly identified in stage C compared to B2 (P&#xa0;<&#xa0;.0001). One hundred and five (49.5%) dogs died during the observation period. Median survival time for the entire study population was 567&#xa0;days (95% CI 512-743). Stage C (P&#xa0;=&#xa0;.003), the presence of PH (P&#xa0;=&#xa0;.009), left atrial to aortic root ratio (LA/Ao) >1.7 (P&#xa0;=&#xa0;.0002), normalized left-ventricular end-diastolic diameter (LVEDn) >1.73 (P&#xa0;=&#xa0;.048), and tricuspid regurgitation pressure gradient (TRPG) >55&#xa0;mmHg (P&#xa0;=&#xa0;.009) were associated with worse outcomes in the univariate analyses. The presence of TRPG >55&#xa0;mmHg (HR 1.8 95% CI 1-2.9; P&#xa0;=&#xa0;.05) and LA/Ao&#xa0;>&#xa0;1.7 (HR 2 95% CI 1.2-3.4; P&#xa0;=&#xa0;.01) remained significant predictors of worse outcome in the multivariate analysis. CONCLUSIONS AND CLINICAL IMPORTANCE: In dogs with MMVD, moderate to severe PH worsens outcome.