Efficacy of pimobendan on survival and reoccurrence of pulmonary edema in canine congestive heart failure.

The aim of this study was to evaluate the efficacy of pimobendan with conventional therapies on survival and reocurrence of pulmonary edema in dogs with congestive heart failure (CHF) caused by myxomatous mitral valve disease (MMVD). Records of 197 client-owned dogs from 14 veterinary hospitals were included in this study. Dogs were administered conventional treatments with or without pimobendan. Sixty-four dogs received a standard dose of pimobendan (0.20-0.48 mg/kg every 12 hr (q12hr)), 49 dogs received a low dose of pimobendan (0.05-0.19 mg/kg q12hr), and 84 dogs received conventional therapy alone. Dogs in the standard-dose and low-dose pimobendan groups had significantly longer median survival times than dogs in the conventional group (334, 277 and 136 days, respectively; P<0.001). The reoccurrence rate of pulmonary edema in the standard-dose group was significantly lower than in the low-dose and conventional groups (43%, 59% and 62%, respectively; P<0.05). Combination of pimobendan with a conventional treatment regimen significantly prolonged survival time after an initial episode of pulmonary edema in dogs with CHF caused by MMVD. There was no difference in survival between dogs administered standard and low doses of pimobendan, but pimobendan did prevent the reoccurrence of pulmonary edema in a dose-dependent manner.

Plasma cytokine levels in dogs undergoing cardiopulmonary bypass.

UNLABELLED: Currently, there are no reports of inflammatory responses to CPB in dogs. We investigated the time course of pro- and anti-inflammatory cytokine levels during and after CPB. ANIMALS: The study group included 11 dogs that underwent mitral valve repair with CPB, and the control group included 7 healthy dogs that underwent ovariohysterectomy. METHODS: Blood samples from the study group dogs were collected before, during and after surgery and analyzed for plasma levels of interleukin-6 (IL-6), tissue necrosis factor-α (TNF-α), interleukin-10 (IL-10), white blood cells (WBC), and C-reactive protein (CRP). Each inflammatory parameter was also compared with that of the control group dogs. RESULTS: After CPB, plasma levels of IL-6, WBC counts, and CRP levels were significantly higher than preoperative levels, and IL-6 levels in the study group were significantly higher than those in the control group. CONCLUSIONS: CPB induces a systemic inflammatory response in dogs.

Successful implantation of autologous valved conduits with self-expanding stent (stent-biovalve) within the pulmonary artery in beagle dogs.

OBJECTIVES: To evaluate the functionality of an autologous heart valve with stent (Stent-biovalve or SBV) after implantation in the pulmonic valve position in beagle dogs. ANIMALS: Five beagle dogs. METHODS: A mold with an aperture of a tri-leaflet structure was constructed from a pair of concave and convex rods to which a nitinol (NiTi) stent was mounted. This mold was embedded in a dorsal subcutaneous pouch in beagle dogs for 4 weeks. At the time of the removal, the surfaces of the molds were completely covered with connective tissues, tri-leaflet valves were formed and the NiTi stent was tightly connected to the structure. RESULTS: The mean burst strength of the SBV leaflet was 2710 mmHg (range 2280-3116 mmHg), which was approximately equal to that of the native pulmonic valve leaflet. After implantation in the pulmonary position, the SBV showed good functionality as a pulmonic valve. At 84 days after implantation, the SBV was replaced with autologous fibroblasts and collagenous tissues, and showed organization similar to that of native heart valves. CONCLUSION: Stent-Biovalves achieved good valvular function with laminar flow in the pulmonic valve position of beagle dogs.

Mitral valve repair under cardiopulmonary bypass in small-breed dogs: 48 cases (2006-2009).

OBJECTIVE: To determine whether mitral valve repair (MVR) under cardiopulmonary bypass would be an effective treatment for mitral regurgitation in small-breed dogs. DESIGN: Retrospective case series. ANIMALS: 48 small-breed dogs (body weight, 1.88 to 4.65 kg [4.11 to 10.25 lb]; age, 5 to 15 years) with mitral regurgitation that underwent surgery between August 2006 and August 2009. PROCEDURES: Cardiopulmonary bypass was performed with a cardiopulmonary bypass circuit. After induction of cardiac arrest, a mitral annuloplasty was performed, and the chordae tendineae were replaced with expanded polytetrafluoroethylene chordal prostheses. After closure of the left atrium and declamping to restart the heart, the thorax was closed. RESULTS: Preoperatively, cardiac murmur was grade 3 of 6 to 6 of 6, thoracic radiography showed cardiac enlargement (median vertebral heart size, 12.0 vertebrae; range, 9.5 to 14.5 vertebrae), and echocardiography showed severe mitral regurgitation and left atrial enlargement (median left atrium-to-aortic root ratio, 2.6; range, 1.7 to 4.0). 45 of 48 dogs survived to discharge. Three months after surgery, cardiac murmur grade was reduced to 0/6 to 3/6, and the heart shadow was reduced (median vertebral heart size, 11.1 vertebrae, range, 9.2 to 13.0 vertebrae) on thoracic radiographs. Echocardiography confirmed a marked reduction in mitral regurgitation and left atrium-to-aortic root ratio (median, 1.7; range, 1.0 to 3.0). CONCLUSIONS AND CLINICAL RELEVANCE: We successfully performed MVR under cardiopulmonary bypass in small-breed dogs, suggesting this may be an effective surgical treatment for dogs with mitral regurgitation. Mitral valve repair with cardiopulmonary bypass can be beneficial for the treatment of mitral regurgitation in small-breed dogs.