Avaliação do fragmento N-terminal do peptídeo natriurético tipo B (NT-ProBNP) em gatos com hipertiroidismo

Dissertação de Mestrado Integrado em Medicina Veterinária

O hipertiroidismo (HT) é a doença endócrina mais frequente em gatos geriátricos. As hormonas da tiróide têm um efeito marcado no sistema cardiovascular. O sopro cardíaco e o ritmo de galope são os sinais clínicos observados mais frequentemente em gatos com alterações cardíacas e surgem secundariamente à hipertrofia concêntrica do ventrículo esquerdo, podendo surgir sinais clínicos de insuficiência cardíaca em casos mais graves. O terminal N do péptido natriurético cerebral (NT-ProBNP) é um biomarcador utilizado para detetar e monitorizar este tipo de alterações cardíacas em gatos com doença cardíaca primária ou secundária. Assim, dada a associação que existe entre o HT e as alterações cardíacas descritas, neste trabalho avaliou-se o potencial do NT-ProBNP para detetar alterações cardíacas em gatos com HT. Além disso, avaliou-se também se o grau de elevação da concentração de NT-ProBNP se correlacionava com a gravidade das alterações cardíacas e com a concentração sérica de T4 total. Este trabalho foi realizado no Hospital Veterinário das Laranjeiras e foram incluídos 5 gatos com HT. Em todos os gatos foi determinada a concentração sérica de T4 total e de NT-ProBNP, e efetuada uma ecocardiografia com ECG em simultâneo. Neste trabalho observou-se que a maioria dos gatos eram Europeus Comuns (n=3), apresentavam idades compreendidas entre os 13 e os 18 anos, eram maioritariamente do género feminino (n=3) e tinham pesos compreendidos entre os 2,6 kg e 4,42 kg. Todos os gatos tinham HT, com concentrações séricas de T4 total que variaram entre os 5,3 e 21,2 μg/dl. A concentração sérica de NT-ProBNP foi superior a 100 pmol/L em todos os animais, valores compatíveis com a presença de doença cardíaca. Além disso, todos os animais tinham alterações ecocardiográficas estruturais ou hemodinâmicas, leves ou moderadas, nomeadamente hipertrofia concêntrica do ventrículo esquerdo. O NT-ProBNP parece ser um bom biomarcador na deteção de alterações cardíacas em animais com HT. Com a exceção de 2 gatos, 1 onde havia a suspeita de doença cardíaca primária e outro que pode ser considerado um outlier, o grau de elevação da concentração de NT-ProBNP parece estar associada com o grau de elevação da concentração sérica de T4 total, apesar de ser apenas uma tendência, uma vez que o número reduzido de animais incluídos neste trabalho não permite retirar conclusões com validade científica.

Hyperthyroidism (HT) is the most common endocrine disease in geriatric cats. Thyroid hormones have a marked effect on the cardiovascular system. Cardiac murmur and gallop rhythm are the most common clinical signs observed in cats with cardiac abnormalities and arise secondary to left ventricular concentric hypertrophy, and clinical signs of heart failure may appear in more severe cases. N-terminal cerebral natriuretic peptide (NT-ProBNP) is a biomarker used to detect and monitor this type of cardiac abnormality in cats with primary or secondary heart disease. Thus, given the association between HT and the cardiac changes described, this study evaluated the potential of NT-ProBNP to detect cardiac changes in cats with HT. In addition, it was also evaluated whether the degree of elevation of NT-ProBNP concentration correlated with the severity of cardiac changes and total serum T4 concentration. This study was carried out at the Laranjeiras Veterinary Hospital and 5 cats with HT were included. Serum total T4 and NT-ProBNP concentration were determined in all cats na echocardiography was performed simultaneously to the ECG. In this study it was observed that most cats were Common European (n = 3), aged between 13 and 18 years old, mostly female (n = 3) and weighed between 2.6 kg and 4.42 kg. All cats had HT, with total T4 serum concentrations ranging from 5.3 to 21.2 μg / dl. Serum NT-ProBNP concentration was greater than 100 pmol / L in all animals, values compatible with the presence of heart disease. In addition, all animals had mild or moderate structural or hemodynamic echocardiographic changes, notably concentric left ventricular hypertrophy. NT-ProBNP has been shown to be a good biomarker in detecting cardiac changes in HT animals. With the exception of 2 cats, 1 where primary heart disease was suspected and one that may be considered an outlier, the degree of elevation of NT-ProBNP concentration appears to be associated with the degree of elevation of total T4 serum concentration, although it is only a trend, since the small number of animals included in this study does not allow conclusions to be drawn with scientific validity. Hyperthyroidism (HT) is the most common endocrine disease in geriatric cats. Thyroid hormones have a marked effect on the cardiovascular system. Cardiac murmur and gallop rhythm are the most common clinical signs observed in cats with cardiac abnormalities and arise secondary to left ventricular concentric hypertrophy, and clinical signs of heart failure may appear in more severe cases. N-terminal cerebral natriuretic peptide (NT-ProBNP) is a biomarker used to detect and monitor this type of cardiac abnormality in cats with primary or secondary heart disease. Thus, given the association between HT and the cardiac changes described, this study evaluated the potential of NT-ProBNP to detect cardiac changes in cats with HT. In addition, it was also evaluated whether the degree of elevation of NT-ProBNP concentration correlated with the severity of cardiac changes and total serum T4 concentration. This study was carried out at the Laranjeiras Veterinary Hospital and 5 cats with HT were included. Serum total T4 and NT-ProBNP concentration were determined in all cats na echocardiography was performed simultaneously to the ECG. In this study it was observed that most cats were Common European (n = 3), aged between 13 and 18 years old, mostly female (n = 3) and weighed between 2.6 kg and 4.42 kg. All cats had HT, with total T4 serum concentrations ranging from 5.3 to 21.2 μg / dl. Serum NT-ProBNP concentration was greater than 100 pmol / L in all animals, values compatible with the presence of heart disease. In addition, all animals had mild or moderate structural or hemodynamic echocardiographic changes, notably concentric left ventricular hypertrophy. NT-ProBNP has been shown to be a good biomarker in detecting cardiac changes in HT animals. With the exception of 2 cats, 1 where primary heart disease was suspected and one that may be considered an outlier, the degree of elevation of NT-ProBNP concentration appears to be associated with the degree of elevation of total T4 serum concentration, although it is only a trend, since the small number of animals included in this study does not allow conclusions to be drawn with scientific validity.