Types of left ventricular remodeling in patients with arterial hypertension in the conditions of the North and possibilities of correcting the identified disorders

The dissertation is devoted to studying the frequency of left ventricular hypertrophy and the variants of its geometric remodeling in patients with arterial hypertension living in the conditions of Yakutia. The work analyzes the morphofunctional parameters of the heart, hemodynamic indices, and accompanying metabolic disorders in men and women, taking into account age, ethnicity, and the duration of residence in the North. Particular attention is paid to the assessment of the arterial wall compliance coefficient as a marker of concentric left ventricular hypertrophy, as well as to the possibilities of pharmacological correction of the identified changes using the combined drug Ekvator. The use of a set of visual computer presentations as a form of intensive prevention and influence on modifiable cardiovascular risk factors is considered separately. The results obtained are of importance for developing a differentiated approach to the treatment of arterial hypertension in the northern regions.

Relevance of the topic. Arterial hypertension (AH) in Russia, as in economically developed countries, is one of the pressing medical and social problems [135, 159, 184]. The significance of AH allows it to be defined as the greatest non-infectious pandemic in human history, determining the structure of cardiovascular morbidity and mortality, the level of which remains high [25, 57, 58, 84, 86, 87, 131, 266]. According to the latest data, an increase in systolic blood pressure (SBP) is recorded in approximately 40% of women and 39% of men [88, 157]. In Yakutia, the number of persons suffering from AH and registered at various healthcare facilities of the republic amounts to 61 thousand people [97]. Various studies have shown a significant influence of age and sex on the level of blood pressure [11, 13]. The danger of elevated blood pressure lies in the fact that, without any clinical manifestations, it leads to damage to target organs and the development of conditions such as myocardial infarction (MI), stroke, and renal dysfunction. The probability of developing these complications in persons with AH increases by 5–7 times [85].

The main cause of cardiovascular complications (CVC) and mortality in AH consists in structural and functional changes of the myocardium and the vascular bed [116]. At the same time, essential significance in determining the prognosis in patients with AH is attached to hypertrophy and the geometric model of the left ventricle [160, 178, 180, 203, 213, 222, 228, 232, 233, 234, 241, 245], since left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular diseases (CVD) and mortality [37, 156, 166, 177, 178, 195, 260, 267], regardless of the level of blood pressure [143, 148, 153, 177, 190, 201, 262]. LVH is the leading component of cardiac damage in AH and is caused not only by compensatory mechanisms, but also, with progression, includes elements of myocardial regression prevailing in the terminal stage of LVH. The risk of cardiovascular catastrophes increases from a minimum of 1.5% of all deaths per 100 person-years with normal geometry, to 1.7% with concentric remodeling (CR), 2.8% with eccentric left ventricular hypertrophy (ELVH), and 7.6% with concentric left ventricular hypertrophy (CLVH) [153, 159, 173, 190, 191, 194, 202, 203, 204, 209, 210, 214, 261]. The size of the heart and the thickness of the myocardium in women are smaller than in men, and therefore the incidence of systolic left ventricular dysfunction among women is significantly lower than in men (0.6 and 2.7%, respectively) [176]. The arterial wall compliance coefficient (CC) is one of the hemodynamic parameters that influences the level of blood pressure [253]. Changes in carbohydrate and lipid metabolism lead to an increase in the stiffness of the arterial bed, which contributes to a decrease in CC in AH [8, 12]. Peculiarities of AH in the North are considered to be its development in young people and a severe clinical course with frequent development of CVC [4, 31, 47, 127, 132]. LVH in Yakutia has been insufficiently studied. Only individual studies devoted to this problem have been conducted. There are no works devoted to the frequency of LVH and the nature of changes in left ventricular geometry, as well as to the possibilities of correction in AH in the conditions of Yakutsk. In the available literature, we have not encountered data on the relationship and assessment of CC in LVH in persons with AH in the conditions of the North. It seems expedient to study the morphofunctional characteristics of the heart, hemodynamic parameters, and metabolic disorders in men and women with AH, which will subsequently allow the formation of a differentiated approach to the treatment of this disease in the conditions of Yakutia.

Aim of the study

To study the frequency of LVH and the types of left ventricular remodeling in AH among inhabitants of Yakutsk and the methods of correcting the identified disorders.

Tasks

1. To determine the frequency of LVH and the types of geometric model of the left ventricle in patients with AH depending on age, sex, and duration of residence in Yakutia.

2. To study the features of hemodynamic parameters in men and women depending on the type of left ventricular remodeling.

3. To evaluate the metabolic background taking into account the geometric model of the left ventricle in patients with AH.

4. To evaluate the clinical effectiveness of therapy with Ekvator according to the dynamics of hemodynamic, morphofunctional, and metabolic parameters in patients with AH in the conditions of Yakutsk.

5. To evaluate the influence of a set of visual presentations on the frequency of modifiable cardiovascular risk factors in patients with AH.

Scientific novelty

For the first time, the types of left ventricular remodeling in persons with AH have been studied depending on sex, age, ethnicity, and duration of residence in the conditions of Yakutsk. For the first time, it has been shown that patients with CLVH exhibit the lowest arterial wall compliance coefficient. For the first time in Yakutia, the clinical effect of the combined drug Ekvator has been evaluated, and a method has been developed for using a set of visual presentations that influences modifiable cardiovascular risk factors in patients with AH.

Practical significance

The results of the study provide information on the frequency of LVH and the nature of left ventricular remodeling in patients with AH depending on sex, age, ethnicity, and duration of residence in Yakutsk. The risk of developing CVC increases in patients with low CC, which determines its diagnostic value in clinical practice.

Analysis of the data from the conducted examination expanded the understanding of the pharmacological properties of Ekvator as a highly effective antihypertensive drug that favorably affects hemodynamic parameters, the 24-hour blood pressure profile, and promotes regression of LVH.

A method of VCP has been developed, and its high effectiveness in the dynamics of reducing cardiovascular risk factors in the group of patients with AH has been proven, which makes it possible to recommend the use of this method for the prevention of AH.

Main provisions defended

1. In patients with AH residing in Yakutsk, all variants of left ventricular remodeling are formed, and normal geometry predominates in 57.8–65% of cases. A dependence of morphometric cardiac parameters on the length of residence in Yakutsk, ethnicity, and sex has been revealed: to a greater extent, these changes were observed in non-native men of Russian ethnicity.

2. In the group of men and women with CLVH, an increase in systolic, diastolic, and pulse pressure and a decrease in the compliance coefficient are observed in comparison with other types of left ventricular remodeling.

3. Ekvator, used in the treatment of patients with AH, has a hypotensive, metabolically neutral, and organoprotective effect; in particular, it causes regression of LVH and an increase in CC.

4. The set of visual presentations (VCP) developed by us has a positive effect on modifiable cardiovascular risk factors.

Implementation into practice

The method of determining CC as a marker of CLVH has been introduced into the practice of examination of patients with AH.

The drug Ekvator is used for the correction of AH in the therapeutic department of the Municipal Healthcare Institution "Yakutsk City Clinical Hospital".

A teaching method using VCP has been developed at the "School of Arterial Hypertension" (SAH). The results of the study are used in lecture courses and in practical classes at the Department of Propaedeutics of Internal Diseases of the Medical Institute of Yakutsk State University.

Approbation of the work

The main provisions of the dissertation were reported and discussed in the form of poster and oral presentations: at the conference of young scientists "Prevention of Cardiovascular Diseases in Primary Healthcare" (Novosibirsk, 2008), at the conference of young scientists "Lomonosov-2008" (Moscow, 2008), at the interregional scientific and practical conference "Cardiovascular Pathology in the Arctic Region of Russia: Fundamental and Applied Aspects" (Yakutsk, 2008), at the scientific and practical conference "Improving the Quality of Medical Care within the Framework of the Implementation of the National Project "Health"" (Yakutsk, 2007), at the II Interregional Scientific and Practical Conference Dedicated to the 50th Anniversary of Higher Education of the Republic of Sakha (Yakutia) "Ecology and Human Health in the North" (Yakutsk, 2007), and at the extended meeting of the Department of Propaedeutics of Internal Diseases of the Medical Institute of Yakutsk State University (November, 2008).

Publications

The number of publications on the topic is 15, of which 3 articles and 2 abstracts are in peer-reviewed journals.

Volume and structure of the dissertation

The dissertation is presented on 154 pages of typewritten text and consists of an introduction, a review of literature, a description of materials and methods, 3 chapters of original results, a discussion of the results, conclusions and practical recommendations, and an appendix. The bibliography includes 270 sources, of which 124 are foreign. The work is illustrated with 30 tables, 8 figures, and 7 diagrams.