Plasma Endothelin‐1 Immunoreactivity in Normal Dogs and Dogs with Acquired Heart Disease

Abstract

We sought to measure plasma endothelin‐1 (ET‐1) concentrations in normal dogs and to compare them with those measured in dogs with acquired heart disease with or without pulmonary edema. A sandwich enzyme‐linked immunosorbent assay kit was validated and used to measure ET‐1 immunoreactivity in plasma samples obtained from 32 normal dogs and 46 dogs with either dilated cardiomyopathy (DCM, n = 27) or degenerative valvular disease (CDVD, n = 19) with (n = 30) or without (n = 16) overt congestive heart failure (CHF). Plasma ET‐1 concentrations (geometric mean, 95% confidence interval of geometric mean) were 1.17 (1.04‐1.32) fmol/mL in the 32 normal control dogs, 1.25 (0.981‐1.60) fmol/mL in 16 dogs with DCM (n = 9) or CDVD (n = 7) without CHF, and 2.51 (2.10‐3.01) fmol/mL in 30 dogs with DCM (n = 18) and CDVD (n = 12) with CHF. Plasma immunoreactivity of ET‐1 was significantly higher in dogs with CHF in comparison with normal dogs (P < .001) and dogs with heart disease without CHF (P < .001). No significant difference was found between normal dogs and dogs with heart disease but without CHF (P < .05). Significant correlations were between plasma ET‐1 concentrations and left atrial: aortic ratio (P < .0001, r2= .39), left ventricular internal dimension at end‐diastole indexed to aortic diameter (P <.0001, r2= .30) or body surface area (BSA) (P= .0071, r2= .10), and left ventricular internal dimension at end‐systole indexed to aortic diameter (P= .0003, r2= .17) or BSA (P= .0008, r2= .15).