Abstract
BackgroundGraves’ disease (GD) is the most common cause of hyperthyroidism and can cause cardiac changes, such as pulmonary hypertension.MethodsThis is a prospective study in which we obtained demographic, clinical, laboratory data and characteristics of the GD, in addition to investigating cardiorespiratory function, focusing on the detection of pulmonary hypertension. Patients were separated into two groups: thyrotoxicosis and euthyroidism. Ninety patients with GD of both sexes, over 18 years of age, were included. The cardiorespiratory assessment included an echocardiographic evaluation, a questionnaire of specific symptoms, spirometry and a six-minute walk test.ResultsThe hyperthyroid group included 42 patients (47.73%) and the euthyroid group 46 patients (52.27%); 78 were women (86.67%). The prevalence of pulmonary hypertension between the hyperthyroidism (48.57%) and the euthyroidism (29.41%) groups was not different. Free thyroxine levels (FT4) (OR 1.266), higher left atrium volume (OR 1.113) and right ventricle diameter were associated with pulmonary hypertension. A direct correlation between FT4 with forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1), as also an inverse correlation between initial oxygen saturation (SpO2) with diagnostic time and drop SpO2 with the ratio between the diastolic velocity E of the mitral flow and the diastolic velocity of the mitral ring (E/e’) were observed in the euthyroid group. An inverse correlation between FT4 levels with walked distance as % of predicted value, and a direct correlation between E/e’ ratio and walked distance as % of predicted value were observed in the hyperthyroid group.ConclusionWe emphasize the importance of a cardiorespiratory reassessment in GD, even after a long-term control of the thyrotoxic state, as we demonstrate that about 30% of these patients remain with PH and are subject to specific treatment.
Highlights
Graves’ disease (GD) is the most common cause of hyperthyroidism causing changes in the cardiorespiratory system, such as tachycardia, increased pulse pressure, dyspnea and, not uncommonly, pulmonary hypertension (PH) [1,2,3,4,5].PH is defined as the mean pulmonary arterial pressure higher than 20 mmHg [6, 7], requiring a high degree of suspicion due to its low prevalence and unspecific signs and symptoms
Most authors evaluated the patients during the thyrotoxic state [27], whereas we demonstrated the relevance of the cardiorespiratory assessment, in the presence of thyrotoxicosis, but even after the control of hyperthyroidism, in search of persistent injury
When comparing patients regarding thyroid hormone status, we found, in this study, that those with PH were related to LA and RV increase, but markers of left ventricular diastolic dysfunction, such as elevated values of PCWP and the E/e’ ratio, were associated with euthyroid patients and not with GD in a thyrotoxic state
Summary
Graves’ disease (GD) is the most common cause of hyperthyroidism causing changes in the cardiorespiratory system, such as tachycardia, increased pulse pressure, dyspnea and, not uncommonly, pulmonary hypertension (PH) [1,2,3,4,5]. PH is defined as the mean pulmonary arterial pressure higher than 20 mmHg [6, 7], requiring a high degree of suspicion due to its low prevalence and unspecific signs and symptoms. It includes dyspnea on exertion, lower limb edema, hepatomegaly due to hepatojugular reflux, and symptoms of low cardiac output such as lipothymia and syncope [4, 8]. Graves’ disease (GD) is the most common cause of hyperthyroidism and can cause cardiac changes, such as pulmonary hypertension
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