Calculation of the cut-off and evaluation of the dynamics of natriuretic peptide for optimization the management of comorbid patients with thyrototoxicosis and heart failure
Objective: to determine the cut-oﬀ of natriuretic peptide for optimization dyagnosis heart failure in comorbid patients with thyrotoxicosis, to assess the dynamics of this indicator during therapy.Materials and methods: 111 patients (58,3±5,6 years) were divided into 4 groups. Te main group consisted of 25 patients with CHD, CHF II-III FC and thyrotoxicosis; the 1st group of comparison - 30 patients with CHD and CHF II-III FC, without thyrotoxicosis; the 2nd group — 30 patients with thyrotoxicosis without CHD, the 3rd group - 26 patients with thyrotoxicosis and CHD, with no signs of CHF. Te fnding of thyroid gland, the level of NT-proBNP was estimated at baseline and afer 6 months therapy. A new cut-oﬀ NT-proBNP for the diagnosis of CHF in comorbid patients was calculated by using ROC analysis.Results: the high concentration of NT-proBNP was detected in all patients (more then 125 pg/ml), in the 2nd comparison group — 225.5 (180.1, 376.1) pg/ml. Te NT-proBNP values in the patients of the 1st and 3rd comparison groups did not diﬀer signifcantly. Te highest level of NT-proBNP was detected in the main group — 712.1 (434.3, 893.9) pg/ml. A cut-oﬀ of this marker for screening CHF in comorbid patients with CHD and thyrotoxicosis was calculated - 556.4 pg/ml (a sensitivity of 72 %, a specifcity of 100 %, an accuracy of 87.2 % (p <0.001)). Afer 6 months therapy in the 2nd comparison group the level of NT-proBNP decreased by 74 % (р<0,0001) and has reached the normal value (64,6 (42,2;76,3)); in the main group the level decreased by 43% and was 406,7 (309,1; 498,6) pg/ml.Conclusions: the patients of all groups showed an increased concentration of NT-proBNP. Te highest level of NT-proBNP was observed in the group of patients with CHF by CHD and thyrotoxicosis. Te level of NT-proBNP was determined - 556.4 pg/ml, which allows us to diagnose CHF in patients with a combination of CHD and thyrotoxicosis.