Monitorização ambulatorial da pressão arterial em pacientes normotensos com hipotireoidismo subclínico / Ambulatory blood pressure monitoring in normotensive patients with subclinical hypothyroidism

FUNDAMENTO: O hipotireoidismo manifesto está associado com elevação da pressão arterial diastólica; entretanto, a associação entre o hipotireoidismo subclínico (HS) e alteração da pressão arterial (PA) é desconhecida. OBJETIVO: O objetivo do presente estudo foi avaliar a monitorização ambulatorial da pressão arterial (MAPA) por 24 horas em pacientes normotensos com HS em comparação a indivíduos normotensos eutireóideos (EU). MÉTODOS: Foi realizado um estudo transversal com 50 participantes (HS = 30 e EU = 20) que não apresentavam diferenças em relação a fatores de risco para hipertensão. A monitorização ambulatorial de pressão arterial foi realizada com um monitor Dynamapa®, utilizando-se um método oscilométrico validado pela AAMI (Association for the Advancement of Medical Instrumentation) e pela BHS (British Hypertension Society). RESULTADOS: Os níveis séricos médios de TSH e T4 livre foram respectivamente 6,9 ± 2,2 µUI/ml e 1,1 ± 0,2 ng/dl em pacientes com HS. Apesar de não haver diferença em relação à média da pressão arterial sistólica e diastólica entre os dois grupos, houve uma correlação positiva entre os níveis de pressão arterial diastólica média (PADM) e os valores séricos de TSH em pacientes com HS (r:0,477; p = 0,004). Essa correlação foi detectada por medidas diurnas (r:0,498; p = 0,002) e noturnas (r:0,322; p = 0,032). CONCLUSÃO: A pressão arterial não diferiu entre pacientes com ou sem HS; contudo, os resultados sugerem que a progressão de hipotireoidismo subclínico para níveis mais elevados de TSH pode aumentar o risco cardiovascular através do aumento da pressão arterial diastólica.

BACKGROUND: Overt hypothyroidism is associated with elevation of diastolic blood pressure; however the association of subclinical hypothyroidism (SH) with arterial blood pressure (ABP) alteration is unknown. OBJECTIVE: The aim of the present study was to evaluate ambulatory blood pressure monitoring (ABPM), over 24 hours, in normotensive patients with SH in comparison to euthyroid (EU) normotensive individuals. METHODS: A cross-sectional study was performed with 50 participants (SH = 30 and EU = 20) that did not differ regarding risk factors for hypertension. The ABPM was carried out with a DINAMAPA TM monitor, using the oscillometric method validated by AAMI (Association for the Advancement of Medical Instrumentation) and by the BHS (British Hypertension Society). RESULTS: The mean serum TSH and FT4 were respectively 6.9 ± 2.2 µUI/ml and 1.1 ± 0.2 ng/dl in SH patients. Although there was no difference in the mean values of systolic and diastolic blood pressure between the two groups, there was a positive correlation between the mean values of diastolic blood pressure (DBP) and serum TSH levels in SH patients (r:0.477; p = 0.004). These correlations were detected at daytime (r:0.498; p = 0.002) and sleep-time (r:0.322; p = 0.032) measurements. CONCLUSION: The blood pressure was not different between patients with or without SH; however, the results suggest that the progression of subclinical hypothyroidism to higher levels of TSH may increase the cardiovascular risk by increasing diastolic blood pressure.

[Ambulatory blood pressure monitoring in normotensive patients with subclinical hypothyroidism].

BACKGROUND: Overt hypothyroidism is associated with elevation of diastolic blood pressure; however the association of subclinical hypothyroidism (SH) with arterial blood pressure (ABP) alteration is unknown. OBJECTIVE: The aim of the present study was to evaluate ambulatory blood pressure monitoring (ABPM), over 24 hours, in normotensive patients with SH in comparison to euthyroid (EU) normotensive individuals. METHODS: A cross-sectional study was performed with 50 participants (SH = 30 and EU = 20) that did not differ regarding risk factors for hypertension. The ABPM was carried out with a DINAMAPA TM monitor, using the oscillometric method validated by AAMI (Association for the Advancement of Medical Instrumentation) and by the BHS (British Hypertension Society). RESULTS: The mean serum TSH and FT4 were respectively 6.9 +/- 2.2 microUI/ml and 1.1 +/- 0.2 ng/dl in SH patients. Although there was no difference in the mean values of systolic and diastolic blood pressure between the two groups, there was a positive correlation between the mean values of diastolic blood pressure (DBP) and serum TSH levels in SH patients (r:0.477; p = 0.004). These correlations were detected at daytime (r:0.498; p = 0.002) and sleep-time (r:0.322; p = 0.032) measurements. CONCLUSION: The blood pressure was not different between patients with or without SH; however, the results suggest that the progression of subclinical hypothyroidism to higher levels of TSH may increase the cardiovascular risk by increasing diastolic blood pressure.