Comparison of N-Terminal Pro-B-Type Natriuretic Peptide Between Cats with Cardiogenic Arterial Thromboembolism and Cats with Occult Cardiomyopathy Without Arterial Thromboembolism

To help assess the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and feline cardiogenic arterial thromboembolism (ATE), the objective of this retrospective study was to compare plasma NT-proBNP concentrations between cats with cardiomyopathy that developed ATE (ATE group) and cats with occult cardiomyopathy that did not develop ATE within 1 year of testing (occult cardiomyopathy [OCM] group). Cats with cardiomyopathy and congestive heart failure (CHF) but no ATE (CHF group) were included for comparison. Cats with cardiomyopathy that had NT-proBNP testing were classified into ATE, OCM, or CHF groups. Clinical, echocardiographic, treatment, and NT-proBNP data from medical records were reviewed and compared among groups. A receiver operating characteristic curve was generated to develop a cutoff point for NT-proBNP. Cats were then compared based on this cutoff point. The ATE group (<i>n</i> = 25) had significantly higher NT-proBNP concentrations than the OCM group (<i>n</i> = 31; <i>p</i> < 0.001); there was no significant difference in NT-proBNP concentrations between the ATE and CHF groups (<i>p</i> = 0.92). The estimated optimal NT-proBNP cutoff point to separate OCM and ATE groups was 491 pmol/L (sensitivity = 96.0%, specificity = 93.5%). Cats with NT-proBNP > 491 pmol/L had a larger left atrium, thicker left ventricle, lower fractional shortening, and higher prevalence of spontaneous echogenic contrast and left atrial thrombi on echocardiography. These preliminary, hypothesis-generating findings suggest that NT-proBNP concentrations > 491 pmol/L may help detect cats with OCM at risk for ATE, but given the limitations of this retrospective study, prospective studies are needed to evaluate the potential utility of this measurement.