Biologic variability of N-terminal pro-brain natriuretic peptide in healthy dogs and dogs with myxomatous mitral valve disease

Introduction

To determine the biologic variability of N-terminal pro-brain natriuretic peptide (NTproBNP) in healthy dogs and dogs with various stages of myxomatous mitral valve disease (MMVD).

Animals

Thirty-eight privately owned dogs: 28 with MMVD and 10 healthy controls.

Materials and methods

Prospective clinical study with comprehensive evaluation used to group dogs as healthy or into three stages of MMVD based on current guidelines. NTproBNP was measured hourly, daily, and weekly. For each group, analytical (CV_A), within-subject (CV_I), and between-subject (CV_G) coefficients of variability were calculated in addition to percent critical change value (CCV) and index of individuality (IoI).

Results

For healthy dogs, calculated NTproBNP values were: CV_A = 4.2%; CV_I = 25.2%; CV_G = 49.3%; IoI = 0.52, and CCV = 70.8%. For dogs with MMVD, calculated NTproBNP values were: CV_A = 6.2%; CV_I = 20.0%; CV_G = 61.3%; IoI = 0.34, and CCV = 58.2%.

Conclusions

Biologic variability affects NTproBNP concentrations in healthy dogs and dogs with MMVD. Monitoring serial individual changes in NTproBNP may be clinically relevant in addition to using population-based reference ranges to determine changes in disease status.