The Effect of Fasting-Diet Therapy on the Functional State of the Cardiovascular System in Patients with Arterial Hypertension and Obesity

The dissertation is devoted to the study of the effect of fasting-diet therapy (FDT) on the functional state of the cardiovascular system in patients with arterial hypertension of stages I–II, including cases combined with obesity. It considers non-pharmacological approaches to blood pressure correction, such as lifestyle modification, physical exercise, and therapeutic fasting, and substantiates the need for a comprehensive assessment of the effectiveness and safety of such interventions.

The study carries out a comparative analysis of clinical, instrumental, and functional indices in patients with arterial hypertension with and without obesity before and after a course of FDT, as well as in prospective observation at 1 and 6 months after the course of therapy. It employs twenty-four-hour blood pressure and ECG monitoring, exercise tests, echocardiography, and assessment of heart rate variability. Particular attention is given to the dynamics of mean twenty-four-hour blood pressure values, the rate of the morning rise of systolic blood pressure, the circadian blood pressure profile, exercise tolerance, indices of intracardiac hemodynamics, and autonomic regulation of heart rate.

In terms of prevalence, arterial hypertension occupies one of the leading places among chronic non-communicable diseases in the adult population [Oganov R.G., 1994]. According to individual studies, elevated blood pressure values have been detected in 25–30% of the adult population [Arabidze G.G., Arabidze Gr.G., 1997; Almazov V.D., Shlyakhto E.V., 2001]; according to the results of the First Expert Report of the Scientific Society for the Study of Arterial Hypertension, the All-Russian Scientific Society of Cardiologists, and the Interdepartmental Council on Cardiovascular Diseases (DAT I, 2000), the number of patients with arterial hypertension rises to 40%. Moreover, patients with mild and moderate hypertension predominate in this population (about 70%), while the proportion of individuals with high blood pressure is relatively small. However, the contribution of mild and moderate arterial hypertension to overall mortality and to the development of complications is considerably greater [Pozdnyakov Yu.M., Volkov V.S., 1998; Nebieridze D.V., 1998]. And it is not only a matter of the high prevalence — patients with high blood pressure values are "compelled" by hypertension to take medications regularly, and they control their blood pressure better. Among patients who have suffered a stroke, about 60% had a mild elevation of blood pressure. According to the data of the WHO committee (1997), mortality from coronary heart disease among patients with arterial hypertension is observed at a level of SBP of 140–159 mmHg in 42.9% of cases, at 160–179 mmHg in 16.9%, and only in 7.2% of all cases of death from coronary heart disease does it occur in persons with an SBP elevation above 180 mmHg. Consequently, in order to exert a noticeable influence on mortality from cardiovascular diseases, it is necessary to actively treat precisely those patients with mild arterial hypertension. Modern antihypertensive therapy is aimed at cardio- and vasoprotection, with the goal of reducing cardiovascular morbidity and mortality [Ivashkin V.T., Kuznetsov E.N., 2001]. Thus, a decrease in SBP by 5 mmHg and by 10 mmHg leads to a reduction in the risk of stroke by 38%, and of coronary heart disease by 16%.

At present, despite the well-developed approaches to combined drug therapy, which make it possible to achieve distinct positive results, and the wide range of modern antihypertensive agents, adequate therapy of arterial hypertension continues to remain an important medical and social problem in Russia. A treatment effect was observed in only 17.5% of women and 5.7% of men. In Western countries this problem is also relevant — blood pressure is adequately controlled in less than 30% of patients with arterial hypertension [3]. At the same time, prolonged adequate therapy of arterial hypertension may even lead to regression of the disease, in particular to a decrease in left ventricular hypertrophy [Kupchinskaya E.G. et al., 2003]. Adequate control of arterial hypertension presupposes twenty-four-hour blood pressure monitoring (ABPM). Recognition of the high clinical value of ABPM was reflected in its inclusion in the latest international guidelines for the management of patients with arterial hypertension. Mean twenty-four-hour blood pressure values correlate significantly more strongly with the degree and severity of target-organ changes than office blood pressure measurement. In addition, ABPM results provide additional information on such indices of adverse status as increased blood pressure variability and a distorted circadian rhythm [Rogoza A.N., 1996].

Since arterial hypertension represents a chronic disease [Pozdnyakov Yu.M., Volkov V.S., 1998], one of the fundamental principles of the treatment of arterial hypertension is the necessity of prolonged (lifelong) antihypertensive therapy. At the same time, side effects may be observed with the use of practically all drugs, and the continuous use by patients of various medicinal preparations substantially increases the probability of their adverse effects.

However, without diminishing the significance and possibilities of pharmacological agents in the treatment of arterial hypertension, it should be noted that modern recommendations for the treatment of this disease are characterized by a considerable emphasis on the necessity of conducting non-pharmacological measures (which include both changes in lifestyle and non-pharmacological interventions) at all stages of treatment [3]. The importance of non-pharmacological interventions as a mandatory component at all stages of treatment is also emphasized in current recommendations developed by authoritative international organizations — WHO, the International Society of Hypertension, and the Joint National Committee of the United States on the Prevention, Detection, Evaluation, and Treatment of Arterial Hypertension. It is noted that effective treatment of a patient with arterial hypertension is impossible without a change in lifestyle. Constant "training" of all regulatory mechanisms of the cardiovascular system and rationalization of nutrition are necessary. Among non-pharmacological interventions with proven effectiveness are normalization of body weight, reduction of dietary salt intake, cessation of smoking, limitation of alcohol consumption, and an increase in physical activity. The conduct of non-pharmacological programmes prior to the prescription of drug therapy is recommended: up to 6 months at an intermediate level of risk and up to 12 months at a low level of risk. An undoubted positive quality of non-pharmacological interventions is their favorable effect on associated risk factors with a minimal risk. Non-pharmacological therapy, in addition to generally accepted recommendations, includes various non-pharmacological interventions: autogenic training with biofeedback [Grigoryev V.M., 2001], graded physical exercises [Efremushkin G.G., Busina E.I., 1995; Kocharov A.M., Novikova N.K., 1996; Martyanova I.I., 2000], muscular relaxation, acupuncture, laser therapy [Alizade I.G., Karaeva N.T., 1994]. The positive effect of altitude hypoxia and hypoxic training in a pressure chamber [Mirrakhimov M.M., 1992], as well as intermittent normobaric therapy [Vorobyev L.P. et al., 1993], has been noted. As the authors point out, a feature of non-pharmacological methods and their undoubted advantage is their influence on the entire organism, rather than on individual links of the disease pathogenesis, as occurs with medication.

At present there is a growing interest in fasting-diet therapy as one of the effective methods of non-pharmacological treatment of somatic diseases. Fasting-diet therapy contributes to weight reduction, decrease in hypodynamia, and abandonment of "bad" habits — tobacco smoking and alcohol abuse. There is confirmed evidence of the positive effect of fasting-diet therapy on the blood pressure level in patients with arterial hypertension of stages I–II [Bzhishkyan-Borodina G.N., 1966; Milovidova S.S., Dunaeva T.M., 1975; Arshina Yu.A., 1993; Samsonov M.A., 1993; Lobkov V.V., 1993; Raigorodsky O.Yu., 1993; Savenkov Yu.I., 1993; Yakovlev V.A., 1997; Vukolova Z.P. et al., 1998; Kokosov A.N., 1998; Voropaeva S.V., 2000; Muravyov S.A., 2001; Muravyov S.A., Makarova G.A., 2004; Filipchenko E.M., Raeva T.Yu., 2001; Korchazhkina N.B. et al., 2005; Fatyanova N.S., 2005], and the hypotensive effect of fasting-diet therapy is at least not inferior to that of drug therapy. It has been reliably established that the conduct of fasting-diet therapy favorably influences many aspects of the functional state of the cardiovascular system [Arshina Yu.A., 1993; Samsonov M.A., 1993; Yakovlev V.A., 1997; Voropaeva S.V., 2000; Muravyov S.A., 2001], but at the same time individual questions concerning the possible effect of fasting-diet therapy on the functional state of the cardiovascular system remain open.

Taking the above into account, at present it seems important to investigate in a comprehensive manner the effect of fasting-diet therapy on the indices of the functional state of the cardiovascular system in patients.

The aim of the study is to establish the effect of fasting-diet therapy on the functional state of the cardiovascular system in patients with arterial hypertension of stages I–II with concomitant obesity and without obesity in prospective observation.

Research objectives.

1. To investigate the functional state of the cardiovascular system in patients with arterial hypertension prior to the application of fasting-diet therapy.

2. To evaluate the effectiveness and safety of fasting-diet therapy by the dynamics of anthropometric indices, mean twenty-four-hour values of systolic and diastolic blood pressure, blood pressure load indices (and other indices according to ABPM data); and also to study the state of ectopic activity and the ST segment level (using data from twenty-four-hour ECG monitoring).

3. To investigate the dependence of changes in anthropometric indices after a course of fasting-diet therapy in patients with arterial hypertension on the dynamics of exercise tolerance (according to exercise test data).

4. To study the dynamics of the state of intracardiac hemodynamics (according to echocardiographic data) and autonomic regulation of heart rate in patients with arterial hypertension after a course of fasting-diet therapy.

5. To compare changes in the indices of the state of the cardiovascular system in patients with arterial hypertension after a course of fasting-diet therapy with the dynamics of these indices in patients with arterial hypertension in the control group.

6. In prospective observation of patients with arterial hypertension who underwent a course of fasting-diet therapy, to analyze the indices of the state of the cardiovascular system at 1 and 6 months after the course of therapy.

Scientific novelty. For the first time, on the basis of a clinical-statistical analysis, it has been established that the method of fasting-diet therapy, when applied in patients with arterial hypertension and concomitant obesity and in patients with a normal body mass index, effectively reduces both systolic and diastolic blood pressure; the antihypertensive effect persists for 6 months of observation without the use of medicinal preparations. It has been shown that when this method of treatment is used, exercise tolerance increases significantly in the group of patients with arterial hypertension combined with obesity, and no decrease in exercise tolerance has been revealed in the group of patients with arterial hypertension without obesity after a course of fasting-diet therapy. A positive effect of fasting-diet therapy on peripheral resistance has been demonstrated regardless of the presence of obesity. A significant decrease in the rate of the morning rise of systolic blood pressure after a course of fasting-diet therapy has been revealed, and a positive effect of the course of fasting-diet therapy on the circadian blood pressure profile has been established both in patients with arterial hypertension and obesity and in the group of patients with arterial hypertension without obesity. In prospective observation, persistence of the hypotensive effect and of a decrease in the level of total peripheral vascular resistance over 6 months has been noted, and the absence of a negative effect of the method of fasting-diet therapy on exercise tolerance has been proved.

Practical significance. On the basis of the results of the study, the effectiveness of this non-pharmacological method of treatment of arterial hypertension and the safety of its application have been demonstrated from the standpoint of the functional state of the cardiovascular system in patients with arterial hypertension. In the course of the study it has been established that the use of fasting-diet therapy is justified both in patients with arterial hypertension of the 1-II degree with concomitant obesity and in patients with arterial hypertension with normal body weight, with the recommended duration of therapeutic fasting up to 14 days. Prospective observation has shown that the positive effect on the indices of the functional state of the cardiovascular system in patients with arterial hypertension persists at 6 months of observation.

Main propositions submitted for defense.

1. The use of fasting-diet therapy in patients with arterial hypertension of the 1-II degree effectively reduces both systolic and diastolic blood pressure, with preservation of the hypotensive effect over 6 months of observation after the course of treatment.

2. After a course of fasting-diet therapy in patients with arterial hypertension, the rate of the morning rise of systolic blood pressure decreases significantly, and a positive effect on the circadian blood pressure rhythm has been noted — an increase in the proportion of individuals with adequate nocturnal blood pressure reduction among those who underwent a course of fasting-diet therapy.

3. In patients with arterial hypertension combined with obesity, after a course of fasting-diet therapy a significant increase in exercise tolerance has been noted, and no negative effect of the course of fasting-diet therapy on the level of exercise tolerance has been established in the group of patients with arterial hypertension without concomitant obesity.

4. With the use of fasting-diet therapy in patients with arterial hypertension, regardless of the presence of obesity, the level of total peripheral vascular resistance decreases significantly.

Implementation in practice. The results of the study have been implemented in the practice of treatment of patients with arterial hypertension in the hospital of the Medical Sanitary Unit "Nefteanik".

Approbation of the work. The results of the studies were reported and discussed at the regional scientific and practical conference "Fasting-Diet Therapy and the Problems of Obesity at the Present Stage" in April 2007 in the city of Tyumen. The dissertation was approved on 18 April 2008 at a meeting of the Problem Commission of the Tyumen State Medical Academy of the Russian Federal Agency for Health Care "Medical-Social and Clinical Problems of the Health of the Population of the West Siberian Territorial-Industrial Complex".

Publications. On the topic of the dissertation, 8 printed works have been published.