Introduction: T he relationship between thyroid hor-mones and cardiovascular disease is well-known, be-ing the subject of research in numerous clinical trials. However, the results of these studies have not always been consistent, some demonstrating a benefit of cor-recting thyroid dysfunction in patients with heart failu-re, but others have been prematurely discontinued due to a trend towards increased mortality in patients with heart failure undergoing thyroid hormone replacement therapy.
Objective: To evaluate the causal relationship between serum TSH levels and the severity of heart failure. Methods: T he study population consisted of 40 pati-ents with a history of thyroid dysfunction and heart failure diagnosed according to the European Cardio-logy Society\’s Cardiovascular Society Cardiovascular Review published in 2016, who were clinically evalu-ated, echocardiographically and by determining NT-proBNP (N-terminal-pro-Brain natriuretic peptide) and to which the serum level of TSH and FT4 have been dosed.
Results: The study included 17 men with average age 71±8.8 years and 23 women with mean age 72.6±10 years. Of the total patients 9 (22.5%) had TSH values within normal range, 21 (52.5%) had elevated TSH, with an average of 13.92±14.24 U / mL and 10 (25%) had low TSH mean value of 0.09±0.1 U/mL. 8 (80%) of patients with hyperthyroidism and 9 (42.8%) of those with hypothyroidism were under specific en-docrinological treatment at the time of evaluation. The mean FT4 in the group of patients with elevated TSH was 1.07±0.32 ng/dL, whereas in those with low TSH it was 1.69±0.31 ng/dL. In the euthyroid group, the average values of NT-proBNP were 1120.9±1114.4 pg/mL, with an ejection fraction (FE) of 48.78±10.5%, in the hypothyroidism group, the mean value of NT-proBNP was 6194.2±4627.2 pg/mL (p=0.009), with FE=41.81±12.46%, and in those with hyperthyroi-dism, NT-proBNP=3224.1±3018.1 pg/mL (p=0.007) FE=50.90±3.98%.
Conclusions: Abnormal TSH values are associated with significantly higher NT-proBNP in patients who associate heart failure and thyroid dysfunction than those with euthyroidism. Increased TSH is also associated with lower left ventricular ejection fraction. TSH can be considered as a prognostic factor in heart fai-lure, but large clinical trials are needed to evaluate the optimal way to correct thyroid dysfunction in this pa-tient population.