Feline comorbidities: cardiovascular and kidney diseases.

practical relevanceCardiovascular and kidney diseases are highly prevalent and frequently coexistent in cats, particularly those of advanced age. Several pathways of interaction between the heart and kidneys likely contribute to progressive functional decline of these systems during disease of one or both. Identification of heart or kidney disease in a cat should prompt the clinician to consider how the disease and its treatment might impact the function of the other organ and how coexisting primary disease of the other might impact case management and patient prognosis. CLINICAL CHALLENGES: A common goal in the management of congestive heart failure, acute kidney injury or chronic kidney disease is to maintain optimal body fluid balance; however, many therapies for disease of one system are at odds with the best interests of the other. For example, treatment of kidney disease often includes parenteral fluid therapy with the goal of maintaining mean arterial pressure and adequate renal blood flow, while diuretics are almost always necessary to reduce capillary hydrostatic pressure in cats with heart failure. Overly aggressive volume expansion or reduction during the management of kidney or heart failure, respectively, can lead to injury to or excessive stress on the other organ system. EVIDENCE BASE: Recommendations are based on available peer-reviewed literature and expert consensus guidelines when available. AUDIENCE: This article is aimed at all veterinary practitioners who work with cats.