Brazilian Journal of Anesthesiology
https://bjan-sba.org/article/doi/10.1590/S0034-70942007000500004
Brazilian Journal of Anesthesiology
Scientific Article

Avaliação dos níveis séricos de hormônios tireóideos em revascularização miocárdica

Evaluation of serum levels of thyroid hormones in myocardial revascularization

Elaine Rahal Rodas Messias; José Otávio Costa Auler Jr; Maria José Carvalho Carmona

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Resumo

JUSTIFICATIVAS E OBJETIVOS: Os hormônios tireóideos tiroxina (T4) e triiodotironina (T3) regulam o anabolismo de proteínas, lipídios e carboidratos e aumentam o consumo de oxigênio. Estresse cirúrgico e circulação extracorpórea (CEC) podem alterar os níveis hormonais ativos por meio de interferência na conversão periférica e diminuição do nível sérico de T3 sem alterações da tirotrofina (TSH), caracterizando a síndrome eutireóidea. Objetivou-se comparar os níveis séricos de T3, T4 e TSH em pacientes submetidos à revascularização miocárdica (RM) com ou sem utilização de CEC. MÉTODO: Foram estudados 18 pacientes com programação para cirurgia eletiva de RM, sendo: Grupo CEC (n = 9): pacientes submetidos à CEC e Grupo sem CEC (n = 9): pacientes não submetidos à CEC. Realizou-se dosagem de T3, T4 e TSH séricos antes da indução anestésica (início SO), ao término da cirurgia (final SO), no primeiro dia (1º PO) e no segundo dia de pós-operatório (2º PO). Na análise estatística (Análise de Variância de medidas repetidas, teste de Mann-Whitney e prova de Friedman) considerou-se significativo p < 0,05. RESULTADOS: Ocorreu diminuição do nível sérico de T3 nos dois grupos. Os níveis séricos de T4 mostraram diferença entre os momentos final SO e 1º PO, quando o grupo não-submetido à CEC mostrou níveis mais elevados de T4. Os níveis séricos de TSH permaneceram dentro dos limites da normalidade. CONCLUSÕES: Ocorre diminuição dos níveis séricos de T3 após revascularização miocárdica com e sem a utilização de CEC e com maior diminuição de T4 no grupo submetido à CEC. A ausência de resposta hipofisária às alterações dos níveis séricos de T3 e T4 caracteriza a síndrome eutireóidea nos dois grupos.

Palavras-chave

CIRURGIA, Cardíaca, HORMÔNIOS

Abstract

BACKGROUND AND OBJECTIVES: Thyroid hormones, thyroxine (T4) and triiodothyronine (T3), regulate anabolism of proteins, lipids, and carbohydrates, and increase oxygen consumption. Surgical stress and cardiopulmonary bypass (CPB) can change active hormone levels by interfering with the peripheral conversion and reducing serum levels of T3, without changing the levels of thyrotropin (TSH), which are the characteristics of the euthyroid syndrome. The objective of this work was to compare serum levels of T3, T4 and TSH in patients undergoing myocardial revascularization (MR) with or without ECC. METHODS: Eighteen patients scheduled for elective MR divided as follows: CPB Group (n = 9): patients undergoing CPB, and the Group without CPB (n = 9): patients that did not undergo CPB. The serum levels of T3, T4 and TSH were determined before anesthetic induction (initial OR), at the end of the surgery (final OR), in the first (1st PO) and in the second (2nd PO) postoperative days. Statistical analysis (Analysis of Variance for repeated measures, Mann-Whitney test, and Friedman test) considered significant a p < 0.05. RESULTS: There was a reduction in serum levels of T3 in both groups. Serum levels of T4 showed differences in final OR and 1st PO, which were elevated in the group that did not undergo CPB. Serum levels of TSH remained within normal limits. CONCLUSIONS: Serum levels of T3 are reduced after myocardial revascularization with and without CPB, with greater reduction in T4 in the group that underwent CPB. The absence of pituitary response to changes in serum levels of T3 and T4 characterized the euthyroid syndrome in both groups.

Keywords

HORMONES, SURGERY, Cardiac

References

Sabatino L, Colantuoni A, Iervasi G. Is the vascular system a main target for thyroid hormones?: From molecular and biochemical findings to clinical perspectives. Curr Vasc Pharmacol. 2005;3:133-145.

Messias ERR, Carmona MJC, Auler Jr JOC. Hormônios tireóideos e cirurgia cardíaca. Rev Bras Anestesiol. 1999;49:403-410.

Ho WM, Wang YS, Tsou CT. Thyroid function during isoflurane anesthesia and valvular heart surgery. J Cardiothorac Anesth. 1989:550-557.

Holland FW 2nd, Brown PS Jr, Clark RE. Acute severe postischemic myocardial depression reversed by triiodothyronine. Ann Thorac Surg. 1992;54:301-305.

Holland FW 2nd, Brown PS Jr, Weintraub BD. Cardiopulmonary bypass and thyroid function: a "euthyroid sick syndrome". Ann Thorac Surg. 1991;52:46-50.

Robuschi G, Medici D, Fesani F. Cardiopulmonary bypass: a low T4 and T3 syndrome with blunted thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH). Horm Res. 1986;23:151-158.

Novitzky D, Cooper DK, Swanepoel A. Inotropic effect of triiodothyronine (T3) in low cardiac output following cardioplegic arrest and cardiopulmonary bypass: an initial experience in patients undergoing open heart surgery. Eur J Cardiothorac Surg. 1989:140-145.

Dyke CM, Ding M, Abd-Elfattah AS. Effects of triiodothyronine supplementation after myocardial ischemia. Ann Thorac Surg. 1993;56:215-222.

Bremner WF, Taylor KM, Baird S. Hypothalamo-pituitary-thyroid axis function during cardiopulmonary bypass. J Thorac Cardiovasc Surg. 1978;75:392-399.

Gayes JM, Emery RW, Nissen MD. Anesthetic considerations for patients undergoing minimally invasive coronary artery bypass surgery: mini-sternotomy and mini-thoracotomy approaches. J Cardiothorac Vasc Anesth. 1996;10:531-535.

Lowenstein E. Implications of triiodothyronine administration before cardiac and noncardiac operations. Ann Thorac Surg. 1993;56:S43-47.

Gotzsche LS, Weeke J. Changes in plasma free thyroid hormones during cardiopulmonary bypass do not indicate triiodothyronine substitution. J Thorac Cardiovasc Surg. 1992;104:273-277.

Klemperer JD. Thyroid hormone and cardiac surgery. Thyroid. 2002;12:517-521.

Bennett-Guerrero E, Jimenez JL, White WD. Cardiovascular effects of intravenous triiodothyronine in patients undergoing coronary artery bypass graft surgery: A randomized, double-blind, placebo-controlled trial. Duke T3 study group. Jama. 1996;275:687-692.

Klemperer JD, Klein I, Gomez M. Thyroid hormone treatment after coronary-artery bypass surgery. N Engl J Med. 1995;333:1522-1527.

Klemperer JD, Klein IL, Ojamaa K. Triiodothyronine therapy lowers the incidence of atrial fibrillation after cardiac operations. Ann Thorac Surg. 1996;61:1323-1327.

Drinka PJ, Nolten WE. Subclinical hypothyroidism in the elderly: to treat or not to treat?. Am J Med Sci. 1988;295:125-128.

Franklyn J. 'Subclinical hypothyroidism': to treat or not to treat, that is the question. Clin Endocrinol (Oxf). 1995;43:443-444.

Reinhardt W, Mocker V, Jockenhovel F. Influence of coronary artery bypass surgery on thyroid hormone parameters. Horm Res. 1997;47:1-8.

Wartofsky L, Burman KD. Alterations in thyroid function in patients with systemic illness: the "euthyroid sick syndrome". Endocr Rev. 1982:164-217.

Cruz PM, Bello CN, Marcial MLB. Aspectos da função tireóidea em lactentes submetidos à cirurgia cardíaca com circulação extracorpórea. Rev Bras Anestesiol. 2004;54:325-334.

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