RESUMO

OBJECTIVE: The diagnosis of subclinical central hypothyroidism in hypothalamic-pituitary patients cannot be established by serum markers of thyroid hormone action. Myocardial function by echocardiography has been shown to reflect thyroid hormone action in primary thyroid dysfunction. We evaluated the performance of echocardiography in diagnosing subclinical central hypothyroidism. DESIGN: Cross-sectional and before and after. METHODS: Echocardiography and serum thyroid hormones were assessed in overt primary (n=20) and central (n=10) hypothyroidism, subclinical primary hypothyroidism (n=10), hypothalamic-pituitary disease with normal free thyroxine (FT(4); n=25), and controls (n=28). Receiver operating characteristic (ROC) curves were generated using overt hypothyroidism patients and selected cut-off values were applied to detect both primary and central subclinical hypothyroidism. After levothyroxine (l-T(4)) intervention, patients were echocardiographically reevaluated at predefined targets: normal thyrotropin (TSH) in primary hypothyroidism, normal FT(4) in overt central hypothyroidism, and higher than pretreatment FT(4) in echo-defined subclinical central hypothyroidism. RESULTS: Parameters with highest areas under the ROC curves (area under the curve (AUC) ≥0.94) were as follows: isovolumic contraction time (ICT), ICT/ejection time (ET), and myocardial performance index. Highest diagnostic accuracy (93%) was obtained when at least one parameter was increased (positive and negative predictive values: 93%). Hypothyroidism was echocardiographically diagnosed in eight of ten patients with subclinical primary hypothyroidism and in 14 of 25 patients (56%) with hypothalamic-pituitary disease and normal serum FT(4). Echocardiographic abnormalities improved significantly after l-T(4) and correlated (0.05

Assuntos

Ecocardiografia Doppler , Doenças Hipotalâmicas/diagnóstico por imagem , Hipotireoidismo/diagnóstico por imagem , Doenças da Hipófise/diagnóstico por imagem , Adulto , Doenças Assintomáticas , Estudos Transversais , Técnicas de Diagnóstico Endócrino , Feminino , Humanos , Doenças Hipotalâmicas/complicações , Doenças Hipotalâmicas/tratamento farmacológico , Hipotireoidismo/complicações , Hipotireoidismo/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Doenças da Hipófise/complicações , Doenças da Hipófise/tratamento farmacológico , Curva ROC , Hormônios Tireóideos/sangue , Tireotropina/sangue , Tiroxina/uso terapêutico , Adulto Jovem