To evaluate cardiovascular functionality in patients with thyroid cancer, we have performed echocardiography and ambulatory blood pressure monitoring in 19 women with differentiated thyroid carcinoma during thyroxine withdrawal, at three time points: the last day on TSH-suppressive thyroxine doses (subclinical or mild hyperthyroidism), 4-7 days after withdrawal (normal free thyroxine (FT4) and free triiodothyronine (FT3) levels), and before 131I whole body scanning (overt hypothyroidism). Twenty-one healthy euthyroid women served as controls. When compared with the values at visit 2, when patients had normal serum FT4 and FT3 levels, night-time systolic and mean blood pressure were increased when the patients were mildly hyperthyroid, and night-time systolic, diastolic and mean blood pressure were increased during overt hypothyroidism. The proportion of nondippers (absence of nocturnal decline in blood pressure) was markedly increased compared with healthy controls (7%), when patients were hyper- or hypothyroid (58% and 50% respectively), but not when patients had normal FT4 and FT3 levels (12%). No changes were observed in office blood pressure or in daytime ambulatory blood pressure readings. Diastolic function worsened during thyroxine withdrawal (E and A waves (early and late mitral flow) decreased, and the E/A ratio and the isovolumic relaxation time increased), and cardiac output decreased in parallel with the decrease in heart rate and systolic blood flow. In conclusion, the chronic administration of TSH-suppressive doses of thyroxine and the withdrawal of thyroxine frequently used for the management of differentiated thyroid carcinoma, are associated with undesirable cardiovascular effects.

This article has been cited by other articles:

				B. Biondi and D. S. Cooper The Clinical Significance of Subclinical Thyroid Dysfunction Endocr. Rev., February 1, 2008; 29(1): 76 - 131. [Abstract] [Full Text] [PDF]

				J. I Botella-Carretero, F. Alvarez-Blasco, J. L. S. Millan, and H. F Escobar-Morreale Thyroid hormone deficiency and postmenopausal status independently increase serum osteoprotegerin concentrations in women Eur. J. Endocrinol., May 1, 2007; 156(5): 539 - 545. [Abstract] [Full Text] [PDF]

				L. H Duntas and B. Biondi Short-term hypothyroidism after Levothyroxine-withdrawal in patients with differentiated thyroid cancer: clinical and quality of life consequences Eur. J. Endocrinol., January 1, 2007; 156(1): 13 - 19. [Abstract] [Full Text] [PDF]

				B Jarzab, D Handkiewicz-Junak, and J Wloch Juvenile differentiated thyroid carcinoma and the role of radioiodine in its treatment: a qualitative review Endocr. Relat. Cancer, December 1, 2005; 12(4): 773 - 803. [Abstract] [Full Text] [PDF]

				J. I Botella-Carretero, A. Prados, L. Manzano, M. T Montero, L. Escribano, J. Sancho, and H. F Escobar-Morreale The effects of thyroid hormones on circulating markers of cell-mediated immune response, as studied in patients with differentiated thyroid carcinoma before and during thyroxine withdrawal Eur. J. Endocrinol., August 1, 2005; 153(2): 223 - 230. [Abstract] [Full Text] [PDF]

				H. F. Escobar-Morreale, J. I. Botella-Carretero, M. Gomez-Bueno, J. M. Galan, V. Barrios, and J. Sancho Thyroid Hormone Replacement Therapy in Primary Hypothyroidism: A Randomized Trial Comparing L-Thyroxine plus Liothyronine with L-Thyroxine Alone Ann Intern Med, March 15, 2005; 142(6): 412 - 424. [Abstract] [Full Text] [PDF]