Survival of dogs with myxomatous mitral valve disease administered preclinical pimobendan in comparison to pimobendan-naïve dogs from the onset of congestive heart failure.

Dogs with MMVD that develop CHF despite preclinical pimobendan may have significantly shorter post-CHF survival times.

This multicentre retrospective study investigated survival times from onset of congestive heart failure (CHF) in dogs with myxomatous mitral valve disease (MMVD) that had received preclinical pimobendan (B2P, n=61) versus pimobendan-naïve dogs (B2N, n=76) at CHF onset. A total of 137 dogs from five centres were evaluated. Notably, at CHF onset, there were no significant differences in patient demographics, echocardiographic parameters, or biochemical variables between groups, suggesting comparable disease severity at presentation. Despite this, dogs in the B2P group had significantly shorter median survival times from CHF onset compared to B2N dogs for both all-cause mortality (168 vs. 359 days, P<0.001) and cardiac death (201 vs. 442 days, P<0.001). The proportion of dogs experiencing cardiac death did not differ between groups (P=0.116). The authors propose several potential explanations, including the possibility that preclinical pimobendan may alter the disease trajectory such that once CHF develops, cardiac reserve is diminished. Importantly, the authors acknowledge that preclinical pimobendan likely remains the optimal overall management strategy for extending quality of life in MMVD dogs with cardiomegaly. However, this study highlights that prior pimobendan exposure should be considered when interpreting CHF survival data and when tailoring treatment strategies for dogs that progress to CHF despite preclinical therapy. Key limitations include the retrospective design and acknowledged underpowering of the study.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.