Evaluation of the association between plasma concentration of N-terminal proatrial natriuretic peptide and outcome in cats with cardiomyopathy

Objective-To determine whether plasma N-terminal proatrial natriuretic peptide (NT-proANP) concentration could predict the outcome (survival duration) of cats with cardiomyopathy (CM). Design-Case-control study. Animals-51 cats with CM (25 with and 26 without congestive heart failure [CHF]) and 17 healthy cats. Procedures-Cats were thoroughly examined and assigned to 1 of 3 groups (control, CM with CHF, and CM alone). Plasma NT-proANP concentrations were measured by use of a human proANP(1-98) ELISA. Survival durations were compared between CM groups. Results-Plasma NT-proANP concentrations differed significantly among the 3 groups, and survival durations differed significantly between the 2 CM groups. Median (range) NT-proANP concentration was 413 fmol/mL (52 to 940 fmol/mL) in the control group, 1,254 fmol/mL (167 to 2,818 fmol/mL) in the CM alone group, and 3,208 fmol/mL (1,189 to 15,462 fmol/mL) in the CM with CHF group. At a cutoff of 517 fmol/mL, NT-proANP concentration had a sensitivity of 90% and specificity of 82% for detecting CM. Multivariate analysis revealed that only the variable left atrium-to-aortic diameter ratio was a significant predictor of survival duration. Conclusions and Clinical Relevance-Plasma NT-proANP concentration may have potential as a testing marker for distinguishing healthy cats from cats with CM. It may also be useful for distinguishing CM cats with CHF from those without CHF The value of NTproANP concentration as a predictor of survival duration was not supported in this study and requires further evaluation. (J Am Vet Med Assoc 2010;237:665-672)