Архивъ внутренней медицины (Sep 2017)
CLINICAL SIGNIFICANCE OF DETERMINING THE LEVEL OF THE BRAIN NATRIURETIC PEPTIDE FOR THE DIAGNOSIS OF HEART FAILURE OF COMORBID PATIENTS WITH CORONARY HEART DISEASE AND THYROTOXICOSIS
Abstract
Aim: To evaluate clinical significance of determining the level of the brain natriuretic peptide for the diagnosis of heart failure of comorbid patients with coronary heart disease and thyrotoxicosis. Materials and methods: 111 patients aged 45 to 65 years (average age was 58.3 ± 5.6 years) were included in the research. All the patients were divided into 4 groups: the main one consisted of 25 patients with thyrotoxicosis, coronary heart disease (CHD) and II-III functional class (FC) chronic heart failure (CHF); the 1st comparison group consisted of 30 patients with coronary heart disease and II -III FC CHF, but without thyroid dysfunction; the 2nd comparison group consisted of 30 patients with thyrotoxicosis without CHD; the 3rd comparison group consisted of 26 patients with thyrotoxicosis and coronary heart disease, without CHF. The following research methods were used in the work: the clinical state assessment scale (CSAS), the 6-minute walk test (6MWT), echocardiography. The level of the N-terminal pro-B-type natriuretic peptide (NT-proBNP) was determined using laboratory sets for enzyme immunoassay (Biomedica, Austria). Results: The comparative analysis of the CSAS indices did not reveal a significant difference in the severity of the clinical symptoms of CHF for the patients of the primary and the 1st comparison group (7.08 and 6.61, respectively, p> 0.05). At the same time, tolerance to physical activity for the patients of the main group was 1.2 times lower than for the patients of the 1st comparison group (p = 0.01). The contractility of left ventricular myocardium for the patients of the main group was significantly lower, as evidenced by the lowest left ventricular ejection fraction — 40.0 (37.0, 42.0)% (compared to patients of all comparison groups, p <0.001). The level of NT-proBNP was increased in all compared groups, including the patients with thyrotoxicosis without combining with IHD and CHF. The values of this index for patients with IHD and CHF and for patients with IHD and thyrotoxicosis without CHF did not differ significantly. The highest concentration of NT-proBNP was obtained in a group of patients with a combination of thyrotoxicosis, coronary heart disease and CHF (p <0.05). The hyperfunction of the thyroid body (gland), apparently, has a stimulating effect on the secretion of natriuretic peptides as the early marker of CHF. Conclusions: At comorbid patients with a thyrotoxicosis and an ischemic heart disease in the conditions of clinically expressed CHF the highest NT-proBNP level, apparently, is caused by influence on production of a natriuretic peptide both hyperfunction of a thyroid gland, and restructuring and a dilatation of cavities of heart, which dictates the need to revise the threshold values of serological markers for the timely diagnosis of heart failure and optimize the maintenance of this category of patients.
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