Nutritional Assessment in a Cat with Congestive Heart Failure

THE CASE

A 10-year-old neutered male domestic shorthaired cat was presented to the emergency room for tachypnea and dyspnea. The cat had previously been healthy, was up-to-date on vaccinations, lived indoors, and was the only animal in the household. On presentation, the cat had a heart rate of 240 bpm, respiratory rate of 68 breaths/minute, weak pulses, and body temperature of 99ºF (37.2ºC). Crackles, muffled heart sounds, and a cardiac gallop were auscultated. The cat’s body weight was 5.3 kg, his BCS was 5/9, and he had normal muscle condition.

Furosemide was administered at 10 mg SC (1.9 mg/kg), and the cat was placed in an oxygen cage. When the cat was breathing more comfortably after a second dose of 10 mg furosemide SC, thoracic radiographs were taken and showed perihilar edema and mild pleural effusion.  

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Dietary History

The owner reported that the cat was fed varying flavors of a commercial cat food (1 pouch 2 times a day) for the past year. The diet history also showed that the cat received no treats, table food, supplements, dental chews, or other foods. A review of the cat food revealed that it was manufactured by a small company and had the following nutritional adequacy statement: “[Brand X] was formulated to meet the nutritional levels established by the Association of American Feed Control Officials (AAFCO) Cat Food Nutrient Profiles for all life stages.” Ingredients listed were “organs (liver, lung, and kidney from beef, pork, and lamb); water sufficient for processing; lamb; starch; potato; calcium.”

Hypertrophic cardiomyopathy was suspected, but an echocardiogram performed the next day showed a dilated, hypocontractile left ventricle and a markedly enlarged left atrium (ie, dilated cardiomyopathy [DCM]). Although most current cases of DCM appear to be taurine-independent, the combination of DCM and the cat’s diet made taurine deficiency a possible factor.  

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DIAGNOSIS:

DILATED CARDIOMYOPATHY 

Further Testing

Plasma and whole blood samples were submitted for determination of taurine concentrations, and cardiac medications and taurine supplementation were initiated. The cat’s diet was analyzed for selected nutrients, and results obtained 2 weeks later showed that the diet was deficient in taurine, as well as in calcium, phosphorus, manganese, potassium, zinc, and thiamine. Plasma (14 nmol/mL; range, 80-120 nmol/mL) and whole blood (67 nmol/mL; range, 300-600 nmol/mL) taurine concentrations were both below the reference range.

Treatment & Follow Up

The cat was discharged from the hospital after 3 days with pimobendan (1.25 mg PO twice a day), furosemide (6.25 mg PO once a day), clopidogrel (18.75 mg PO once a day), and taurine (250 mg PO twice a day, using an independently tested brand to ensure good quality control¹). Instructions to feed a specific good-quality, low-sodium diet (canned and dry) were provided to the owner, as were the reasoning behind the recommendation and more objective ways to select a good-quality diet.

The veterinary team followed up with the owner after discharge to ensure the cat was tolerating the medications and diet and to allow the owner to ask questions regarding the ongoing treatment protocol. The cat was presented for re-evaluation 10 days later. BUN, creatinine, and electrolytes were within normal limits, systolic blood pressure was 150 mm Hg, and the cat was reported to be eating well and breathing normally. An echocardiogram performed 8 weeks later showed improved ventricular size and function; normal size and function returned by 6 months. Cardiac medications were discontinued after 6 months, but the owner continued to feed the good-quality cat food recommended by the veterinarian. The taurine supplement was discontinued after 1 year.

Conclusion

This case illustrates the importance of a nutritional assessment of every patient at every visit.  The nutritional assessment is a team approach and should evaluate the patient’s body weight, BCS, muscle condition score, and diet history. Forms and tips to make this important assessment quick and efficient can be found on the WSAVA Nutrition Toolkit website (see Resources). Dietary history can help identify a diet that is contributing to the underlying disease (as in this case), nutritionally unbalanced, or not optimized for an animal’s life stage or medical conditions.

Global Note

In many parts of the world, there is a lack of oversight and governing bodies pertaining to veterinary foodstuffs. The American Association of Feed Control Officials (AAFCO) is based in the United States. For countries that do not follow AAFCO guidelines, the National Research Council, which is also based in the United States, provides minimum and adequate nutrient profile recommendations that diets should follow. AAFCO guidelines are based on these evidence-based recommendations, with an additional 25% buffer for bioavailability in diet formulation.

Counterparts to the above United States-based nutritional guidelines also exist in some parts of the world. Like AAFCO, FEDIAF, the European Pet Food Industry Federation, produces labeling guidelines. In Australia, nutritional standards are based on the AAFCO profile, but for therapeutic diets the European PARNUTS* regulation is employed. The Russian veterinary authority, Rosselhoznadzor, has specified nutritional profiles for food products for export to Russia, which are a 1:1 copy of the FEDIAF profiles. The Mexican and Japanese industries follow AAFCO profiles. China is working on nutritional standards that may be based on FEDIAF provisions, and the Brazilian trade association, ABINPET, will soon publish a new pet food manual.

Although not a regulatory body, the WSAVA Global Nutrition Committee developed the Nutritional Assessment Guidelines and their subsequent Nutritional Toolkit to address the need for nutrition to play a more central and consistent role in providing optimal pet health by promoting nutritional assessment as the fifth vital sign in every veterinary examination.

*PARNUTS is the term for foodstuffs for particular nutritional uses. These have a special composition or manufacturing process that distinguishes them from foodstuffs for normal consumption.

BCS = body condition score, BUN = blood urea nitrogen, DCM = dilated cardiomyopathy

Diet in Disease is a series developed by the World Small Animal Veterinary Association (WSAVA), the Academy of Veterinary Nutrition Technicians, and Clinician’s Brief.