1、 Overview
Hypertension refers to a group of clinical syndromes with elevated systolic or diastolic blood pressure. The systolic blood pressure and diastolic blood pressure were 12.0-18.7 kPa (90-140 mmHg) and 6.7-12.0 kPa (50.4-90.2 mmHg) respectively. According to who, hypertension can be diagnosed in adults with systolic blood pressure of 21.3kpa (157mmhg) or diastolic blood pressure of 12.7kpa (95.5mmhg). As one of the modern civilized diseases, hypertension is the most common cardiovascular disease, which has great harm to human health.
Hypertension has the characteristics of "three high" and "three low". "Three high" means: the incidence rate is high. According to WHO estimates, 700 million people worldwide have hypertension, and the number of hypertension in China has reached 130 million. At present, China's sampling survey of people over 15 years old shows that the prevalence of hypertension in China has increased from 5.11% in 1959 to more than 12%, more than 100 million people, and it is still increasing at the rate of 3.5 million people per year; the disability rate is high, in terms of stroke, 75% of them lose their ability to work, 40% of them are severely disabled, unable to take care of themselves, and 8% of them are suffering from renal failure; death High rate, 3 million people die of high blood pressure every year in the world, "three low" refers to: low awareness rate, usually referred to as the disease without omen, only about 35% of patients know that they have high blood pressure; low drug taking rate, mainly because people do not attach great importance to the harm of high blood pressure, take medicine when they feel uncomfortable, stop taking medicine when symptoms disappear, thus delaying life; control rate Low, the survey shows that only 4.1% of urban and 1.2% of rural patients with hypertension have been effectively controlled.
2、 Pathogenesis of hypertension
The human heart is like a pump, which continuously inputs blood into the arterial system. When blood flows in the blood vessel, the pressure on the vessel wall is called blood pressure. Blood pressure is divided into arterial blood pressure and venous blood pressure. What we often say is arterial blood pressure. High blood pressure refers to arterial blood pressure higher than normal. Hypertension is divided into primary hypertension and secondary hypertension (also known as symptomatic hypertension). Secondary hypertension is caused by some diseases, such as kidney disease, endocrine dysfunction, renal artery stenosis, craniocerebral disease, etc., which usually only accounts for about 10% of patients with hypertension. Generally, the cause of hypertension is eliminated, and the symptoms of hypertension can disappear. Primary hypertension, also known as primary or spontaneous hypertension, has not been fully identified.
The following factors play an important role in the pathogenesis of hypertension:
1 genetic factors
Essential hypertension is a multi gene genetic disease, its gene expression is largely affected by the environment, and its regulation mechanism needs further study. Among the genetic factors, racial differences are obvious. Black Americans are twice as likely to have high blood pressure as white Americans, and high blood pressure tends to be inherited in families.
Changes of cardiac output
The level of arterial blood pressure mainly depends on the regulation of cardiac output and peripheral vascular resistance. The factors that can directly or indirectly lead to the increase of cardiac output and peripheral vascular resistance can cause the increase of blood pressure, otherwise, it can reduce blood pressure. In addition, the changes of aortic compliance and blood volume can also regulate blood pressure.
3 renal function
Kidney is the main organ regulating water, electrolytes, blood volume and excretion of metabolites in the body. Abnormal renal function can lead to * elevated water, sodium retention and blood volume, which can lead to hypertension. In addition, the kidney can also secrete the substances of pressor and depressor, so the kidney plays an important role in maintaining blood pressure balance.
Abnormal decrease of ion transport in 4 cell membrane
Under pathological conditions, the imbalance of renin-a-aldosterone system regulation can be an important cause of hypertension. Through the study of the concentration gradient of sodium and potassium ions on both sides of the cell membrane, it is found that there is a low co-operation function of inward sodium and potassium in patients with essential hypertension and the inhibition of sodium pump, resulting in the increase of sodium ions in the cells. The latter not only promotes the arteries At the same time, it increases the permeability of vascular smooth muscle cell membrane to calcium ion, increases the calcium ion in vascular, strengthens the excitation contraction coupling of vascular smooth muscle, makes vascular contraction and / or spasm, and leads to the increase of resistance and blood pressure of peripheral blood vessels.
5. Wall thickening due to high tension
At present, it is considered that the imbalance of self-regulation of circulation leads to the increase of tension of arterioles and venules, which is an important cause of hypertension. The increase of total peripheral vascular resistance in patients with hypertension is not only related to vascular tension, but also closely related to the change of vascular tissue structure. The main manifestations are thickening of vascular wall, hypertrophy and proliferation of smooth muscle cells in the middle of vascular wall, and thinning and reduction of resistance vessels.
6 increased sympathetic activity
Sympathetic nerves are mainly distributed in the cardiovascular system, catecholamine released by increased sympathetic excitability mainly acts on the heart, which can lead to increased heart rate, myocardial contractility and cardiac output. As one of the main neurotransmitters of sympathetic nerve, noradrenaline has strong vasoconstrictive and pressor effects, indicating that sympathetic dysfunction plays a role in the pathogenesis of hypertension. At present, it is believed that the increase of sympathetic activity is mainly involved in the early initiation mechanism of essential hypertension, but has little effect on the long-term maintenance of hypertension.
Renin-angiotension-aldosterone system
This system is composed of a series of hormones and corresponding enzymes. It plays an important role in regulating water, electrolyte balance, blood volume, vascular tension and blood pressure. Under normal circumstances, renin, angiotension and aldosterone are in dynamic equilibrium, feedback and inhibition each other. When the increase of Angiotension can cause the contraction of renal vessels, increase the reabsorption of sodium ions in proximal renal tubules, thus inhibiting renin secretion. Renin can inhibit the secretion of aldosterone, while too much aldosterone will in turn activate renin.
The characteristics of hypertension
（1） Vulnerable population
1 main reasons. Long term high tension of spirit is easy to cause dysfunction of cerebral cortex, affect sympathetic nerve and adrenaline, accelerate heart contraction, increase blood output, and increase blood pressure.
Fat people with more salt are prone to high blood pressure. Obesity and high salt intake of people prone to high blood pressure has been widely recognized by the international community. Therefore, fat people should reasonably arrange their diet, eat less salt and control their weight.
High blood pressure is easily caused by bad habits such as smoking and drinking. Although there is no direct evidence that smoking and drinking can lead to hypertension, a large proportion of people with bad habits such as smoking and drinking are found in the survey of hypertension patients. So people who have high blood pressure must stop smoking and drinking.
Diabetes patients are prone to high blood pressure.
（2） The incidence trend of modern hypertension is increasing, which has become a social problem that can not be ignored. There are several reasons for the increase of incidence trend of teenagers:
1. Genetic factors. Research shows that as long as the grandparents have a history of hypertension, coronary heart disease, and stroke, the children's blood pressure will be on the high side, of which stroke is the most influential. The prevalence of hypertension in children with positive family history is about three times higher than that in children with negative family history.
2 obesity and overweight. This is the most important and decisive factor in the environment, as is the case with different races, ages and genders. Obesity can not only raise blood pressure, but also advance the occurrence of atherosclerotic arteriosclerosis, and cause hyperlipidemia, diabetes and fatty liver. Obesity itself can increase the prevalence of hypertension by 2-3 times, but if it exists at the same time with family history, the prevalence is not a simple addition but a multiplication relationship.
Bad dietary habits. The blood pressure of the people who eat salt, high fat, low calcium, potassium, magnesium and cellulose is high, so a reasonable diet plays an important role in preventing hypertension.
Bad habits such as smoking. Although the relationship between smoking and hypertension is not very clear, the increase of total serum cholesterol and low-density lipoprotein, the decrease of high-density lipoprotein, the increase of platelet adhesiveness and aggregation, the shortening of coagulation time, and the increase of fibrinogen concentration in plasma can promote atherosclerosis. Moreover, smoking can cause coronary heart disease and early lung cancer in young people.
3、 The harm of hypertension
Hypertension is the biggest epidemic disease today, and is the arch criminal of cardiovascular and cerebrovascular diseases. It has the characteristics of high incidence rate and low control rate. The real harm of hypertension lies in the damage to heart, brain and kidney, which causes serious pathological changes of these important organs.
1 stroke
Stroke is the most common complication of hypertension. The most serious stroke is cerebral hemorrhage, and hypertension is the main cause of cerebral hemorrhage, which is called hypertensive cerebral hemorrhage. High blood pressure will increase the tension of blood vessels, that is to say, it will "tighten" the vessels. If the time is long, the elastic fibers of the vessel wall will break, causing damage to the vessel wall. At the same time, lipid soluble substances in the blood will penetrate into the intima of the blood vessel wall, which will make the cerebral artery lose its elasticity and cause cerebral arteriosclerosis. The adventitia and middle layer of cerebral artery are thinner than those of other parts. On the basis of the pathological changes of cerebral artery, when the blood pressure of the patient rises suddenly, the possibility of cerebral hemorrhage will occur. If the patient's blood pressure suddenly drops, there will be cerebral thrombosis.
2 coronary heart disease
Coronary heart disease is the abbreviation of coronary atherosclerotic heart disease, which refers to the heart disease caused by myocardial ischemia and hypoxia caused by coronary atherosclerosis. Hypertension is an independent risk factor for coronary heart disease. Research shows that 60% - 70% of patients with coronary atherosclerosis have high blood pressure, which is four times higher than that of patients with normal blood pressure.
Kidney damage
The most serious damage of hypertension is the renal blood vessels, which will lead to the narrowing or rupture of renal blood vessels, and eventually lead to renal failure.
Hypertensive heart disease
Hypertensive heart disease is an inevitable result that hypertension can not be controlled for a long time. Hypertension will aggravate the burden of pumping blood, enlarge the heart, reduce the efficiency of the pump, and cause arrhythmia and heart failure, thus endangering life.
