Hypertrophic cardiomyopathy (HCM) is the most common feline heart disease. Currently, echocardiography is the gold standard to diagnose feline HCM, including occult forms of the disease. However, this imaging technique requires expertise to interpret the data and represents a financial cost for the owner, thus limiting its widespread use for screening "apparently healthy" cats. Therefore, a rapidly assessed biomarker, such as a pet-side test able to identify asymptomatic HCM cats would be of interest.

Previous studies showed that the circulating cardiac biomarker N-terminal pro-B-type natriuretic peptide (NT-proBNP) is significantly increased in cats with moderate to severe occult HCM, as compared to healthy cats. The aim of this prospective study was to determine the sensibility (Se) and specificity (Sp) of the Idexx SNAP Feline proBNP Test to diagnose HCM in asymptomatic adult cats.

Material and Methods

The study population consisted of prospectively recruited "apparently healthy" adult cats (2015–2017), with or without heart murmurs. Cats with congenital heart diseases, with other cardiomyopathy than HCM, with current or past diagnosis of congestive heart failure, and with gallop rhythm, were not included in the study. All cats underwent a complete physical examination, blood pressure measurement, serum urea and creatinine measurements, and conventional echocardiography. Total T4 was also assessed in cats >6 years old. Plasma NT-proBNP concentration was measured using EDTA-potassium samples and a commercially available feline specific assay. A Snap Feline NT-proBNP was also performed (positive detection limit: 200 pmol/L), according to the manufacturer's instructions.

Results

The study population consisted of 61 "apparently healthy" cats (29 males and 32 females; median age: 4.9 years [1.1–16.6]; body weight: 4.6 kg [2.5–10.5]): 31 normal cats with both normal cardiac auscultation and echocardiography and 30 asymptomatic cats with a left apical systolic heart murmur either related to HCM (n=9; 6 diffuse HCM forms and 3 segmental HCM forms with hypertrophy of the sub-aortic interventricular septum) or to a minor to mild mitral valve regurgitation without any other echocardiographic abnormality (MVR; n=21). The SNAP test distinguished asymptomatic HCM cats from other "apparently healthy" cats (i.e., normal cats or cats with minor to mild MVR) with 64% sensibility (Se) and 100% specificity (Sp), the negative and positive predictive values were 93% and 100% respectively and when only considering diffuse HCM forms with 100% Se and 100% Sp.

In conclusion, the SNAP Feline NT-proBNP Test may help identifying diffuse HCM forms in asymptomatic cats.

Disclosures

Disclosures to report.

Study financed by IDEXX's laboratories.