Plasma atrial/A-type natriuretic peptide (ANP) concentration in horses with various heart diseases

Abstract Objective Plasma atrial/A-type natriuretic peptide concentration (Cp ANP ) was measured in horses presenting with various heart diseases to assess its potential diagnostic value. Animals Fifteen healthy horses ( Group 1 ) and 60 horses with various heart diseases associated with normal chamber size and function ( Group 2, n = 24 ), associated with abnormal left atrial (LA) size and/or function but normal left ventricle (LV) ( Group 3, n = 19 ), or associated with both abnormal LA and LV size and/or function ( Group 4, n = 17 ). Methods Cp ANP was measured by a commercially available radioimmunoassay. Echocardiographic measurements were compared between groups by one-way ANOVA and Holm-Sidak post-hoc test. Receiver operating characteristics (ROC) analyses were performed to identify the best cut-offs to distinguish between groups. Relations between echocardiographic measurements and biomarker concentrations were assessed with backward stepwise multiple linear regression. Results Cp ANP increased from Group 1 to 4 and was significantly higher in horses with heart disease than in controls. Cp ANP was associated with maximum LA area and LV fractional area change. The ROC analyses showed good specificity but poor sensitivity to distinguish between healthy horses and horses with heart disease overall, and between healthy horses and horses with altered left-sided chamber dimensions and/or function. Conclusion Cp ANP is increased in horses with heart disease associated with altered left-sided chamber dimensions and/or function. However, its diagnostic value is compromised by poor sensitivity.