C04 - Significance of Degenerative Tricuspid Valve Disease in Dogs that have Undergone Mitral Valve Repair

Abstract: Background: Dogs that undergo mitral valve repair (MVR) for degenerative mitral valve disease (DMVD) frequently have degenerative tricuspid valve disease (DTVD). The significance of DTVD in these dogs has not been studied, therefore it is currently challenging to know if concurrent or subsequent tricuspid valve repair should be considered.
Hypothesis: DTVD is common in dogs that have undergone MVR but right-sided congestive heart failure (R-CHF) because of DTVD is rare.
Animals: 83 dogs that had MVR surgery.
Methods: Retrospective study. Case history and echocardiographic reports of dogs that had undergone MVR were reviewed. Dogs with severe pulmonary hypertension (PHT) were excluded from outcome analysis.
Results: Study dogs represented 26 different breeds; median age was 9y (range 5–14y) with a mean follow-up time of 1.6y. Prior to MVR 27% of dogs had moderate-severe tricuspid regurgitation (TR) and there was no difference in the proportion of dogs with moderate-severe TR at each follow-up (1mo, 6mo, 1y, 2y and 3y, p=0.25). At date of last follow-up 59/83 (71%) dogs had tricuspid regurgitation documented. One dog developed severe PHT and R-CHF 6mo post-MVR. Severe DTVD (without PHT) occurred in 2/83 (2.4%) dogs, with onset of R-CHF at 1y and 4y post-MVR. The former dog was alive at last follow-up (3y) and the latter dog was euthanized 4.5y post-MVR due to R-CHF.
Conclusions and clinical importance: Progression of DTVD to R-CHF is rare and therefore simultaneous tricuspid valve repair in dogs undergoing MVR is not justified and would likely present an additional unnecessary risk.