Cardiovascular disease is common in both dogs and cats, although few efforts have been made to identify the roles that endothelial dysfunction plays in these diseases. Although cardiovascular diseases such as myocardial, pericardial, and valvular heart diseases are a frequent cause of disability in companion animals, atherosclerotic coronary artery disease is almost nonexistent in companion animal species. Tests commonly used to characterize cardiovascular disease in clinical veterinary medicine include history, physical examination including auscultation, direct and indirect blood pressure measurement, thoracic radiography, electrocardiography, and echocardiography. Echocardiographic techniques include two-dimensional, M-mode, spectral Doppler, and color-flow Doppler echocardiography. Specific clinical tests to evaluate endothelial function, such as flow-mediated vasodilation and venous plethysmography, commonly are not used, and normal values have yet to be published for clinical application in dogs and cats. Preliminary investigations into the biochemical markers that may reflect endothelial dysfunction in certain diseases have been reported for certain cardiovascular disorders; however, these tests are not used in clinical practice. Although the study of endothelial function in veterinary patients is still in its infancy, many investigators believe that endothelial dysfunction is associated with the common cardiovascular disorders in dogs and cats. This chapter approaches the topic from a brief review of the common cardiovascular diseases in dogs and cats with an accompanying summary of information related to endothelial function.

COMMON SPONTANEOUS CARDIOVASCULAR AND ENDOTHELIAL DISEASE IN DOGS

Chronic Valvular Heart Disease

Chronic valvular heart disease is the most common cardiovascular disease in dogs and is the most common cause of congestive heart failure (CHF) (1). Chronic valvular heart disease is most analogous to the floppy mitral valve syndrome in humans, and it is a progressive, degenerative disorder of the valve.