Reina-Doreste Y, Stern JA, Keene BW, et al. Case-control study of the effects of pimobendan on survival time in cats with hypertrophic cardiomyopathy and congestive heart failure. J Am Vet Med Assoc. 2014 Sept 1; 245(5):534-539.
Pimobendan is a positive inotropic and vasodilatory drug used for the treatment of congestive heart failure (CHF) in dogs and humans. The investigators with this study assessed the survival time and adverse events related to giving pimobendan to cats with CHF secondary to hypertrophic cardiomyopathy (HCM) and hypertrophic obstructive cardiomyopathy (HOCM).
The study was a retrospective look at 27 cats receiving treatment with pimobendan and 27 cats treated without pimobendan. Data collected included signalment, findings from physical examination, ECG data, serum biochemical values, and survival time from when the initial diagnosis of CHF was made. CHF is generally a combination of pulmonary edema, pleural, pericardial, and abdominal effusions. Further consequences can consist of arrhythmias, sudden death, and thromboembolic disease. Standard therapy frequently comprises the use of diuretics, angiotensin-converting enzyme inhibitors, and antiplatelet drugs. Pimobendan, used as a positive inotropic agent, is contraindicated in the face of an obstruction of the outflow tract; so as a therapy, the drug is not recommended for these patients. Cats with HOCM may find their treatment to be variable depending on the clinician and the severity of the obstruction.
The results showed a clear and significant benefit in survival time in this study with the addition of pimobendan to standard treatment regimens. For cats receiving pimobendan, the median survival time was 626 days compared to the median survival time of 103 days for cats not receiving pimobendan. Also, no adverse events were reported in case versus control cats in the study. Pimobendan was well tolerated by cats with CHF secondary to HCM and HOCM. A pharmacokinetic study of pimobendan in cats demonstrated a longer half-life in cats after administration compared to dogs.
Therefore, the addition of pimobendan to traditional treatment for CHF may offer a significant clinical benefit in survival time for cats with HCM and possibly those cats with HOCM affected with CHF. (VLT)