Diagnosis of congestive heart failure by combining echocardiography and blood biomarkers in cats with cardiomyopathy

Abstract

Introduction/Objectives

In cats with cardiomyopathy, echocardiographic indices and blood biomarkers such as atrial natriuretic peptide (ANP), cardiac troponin I (cTnI), and N-terminal pro-B-type natriuretic peptide (NTproBNP) are useful in diagnosing congestive heart failure (CHF). However, the improvement in diagnostic accuracy by combining these indicators remains unclear.

Animals, materials and methods

Twenty-six cats diagnosed with cardiomyopathy using echocardiography were included in this study. They were classified into CHF and non-CHF groups according to the presence of pulmonary oedema or pleural effusion and response to heart failure treatment. The discriminative ability of each index for the presence of CHF was evaluated using a receiver operating characteristic curve.

Results

The left atrial-to-aortic root ratio (LA/Ao) had the highest area under the curve of 0.952 (95% confidence interval [CI]: 0.878–1.0), followed by ANP 0.915 (95% CI 0: 0.808–1.0), cTnI 0.861 (95% CI: 0.722–0.999), and NTproBNP 0.830 (95% CI: 0.672–0.988). Adding NTproBNP and ANP to the LA/Ao did not improve the discriminative ability. Limited by the combination of blood biomarkers, ANP and cTnI showed the highest discriminative ability.

Study Limitations

Following were the limitations to this study: lack of standardised medication, inability to calculate true correlation for NTproBNP values >1500 pmol/L, marked difference in disease severity between groups, inclusion of various cardiomyopathy types, reliance solely on LA/Ao for left atrial size assessment, and small sample size.

Conclusions

This study indicates that if LA/Ao can be measured accurately, the significance of measuring cardiac biomarkers for diagnosing CHF in cats with cardiomyopathy is low.