NT‐proBNP as a diagnostic marker of dilated cardiomyopathy in dogs
Authors: Nikitina Anastasia , Sergeev Dmitriy , Kovalev Sergey , Trushkin Vyacheslav 
Published: May 2022

In dogs of service breeds, cardiopathology is one of the most common diseases of non‐infectious etiology. Dilated cardiomyopathy (DCM) is frequently reported among other heart conditions in large and giant breed dogs. As a result of our previous work, it has been established that DCM of varying severity is recorded in no less than 25% of service dogs. The diagnosis at the later stages of development is not difficult ‐ an enlarged cardiac silhouette on the roentgenogram, enlarged cavities of the heart chambers with echocardiography, ventricular extrasystoles on the electrocardiogram, and a drop in blood pressure during tonometry. Treatment at the late stages of DCM is ineffective and prolongs the dog's lifespan by an average of 3 months. It is advisable to start treatment when the dog is in the early stages of DCM development. However, it is not so easy to identify the disease at the initial stage using visual diagnostics. Therefore, additional methods for diagnosing heart function are required, among which serological analysis for brain natriuretic peptide (NT‐proBNP) can be distinguished. The study aimed to determine the sensitivity of NT‐proBNP in large and giant breed dogs suspected of having DCM disease. Study inclusion criterion: dogs used in security and search work; large or giant breeds; age 2‐8 years; vaccination against rabies, leptospirosis, plague of carnivores, adenovirus infection, parvovirus enteritis, viral hepatitis; absence of diseases of infectious, invasive, and non‐infectious etiology for the last 3 months. In the experiment, 24 dogs were used, which were divided into three groups: group 1 ‐ dogs with significant dilatation of the heart cavities, rhythm disturbances, and a drop in blood pressure (n = 8); Group 2 ‐ dogs with moderate dilatation of the heart cavities, ECG changes, a moderate decrease in blood pressure (n = 8); Group 3 ‐ animals that had no abnormalities during ultrasound diagnostics in the state of the heart (n = 8). An enzyme‐linked immunosorbent assay determined the NT‐proBNP activity. Thus, in dogs of group 1, the NT‐proBNP activity was increased to 4381.7 ± 281.1 pmol / l, which is 20.5 times higher (p <0.05) than in healthy dogs. Severe DCM was confirmed in these dogs. In group 2 animals, the NT‐proBNP level exceeded the values of healthy animals and amounted to 831.7 ± 94.5 pmol / l, which is 3.9 times higher than the normal values. Despite the absence of changes detected during visual diagnostics of the heart, in 2 of 8 dogs of group 3, NT‐proBNP increased to 467.8 ± 15.4 pmol / L. It was increased 2.1 times, which suggested a violation of cardiac activity in these animals. Repeated diagnostics of these 2 dogs 9‐15 months after the start of the study revealed changes characteristic of DCM ‐ changes in the electrical activity of the heart, dilatation of the heart chambers, changes in blood pressure. Based on the experiment results, it was concluded that serological analysis for NT‐proBNP level is a sensitive test that can be included in the list of DCM differential diagnoses.