It is very important to understand the characteristics and misunderstandings of hypertension in the elderly!

Hypertension in the elderly is one of the main diseases that threaten the health and life of the elderly. Epidemiological survey data show that the prevalence rate of hypertension in the elderly in China is as high as 40%~60%, which has become the most important risk factor for the incidence and death of cardiovascular and cerebrovascular diseases in the elderly in China. Because hypertension in the elderly is different from non-elderly people in terms of pathogenesis, clinical manifestations, diagnosis and treatment, understanding and mastering these characteristics will help improve the diagnosis and treatment level of hypertension in the elderly.

Hypertension in the elderly refers to those who are over 60 years old and have a systolic blood pressure of ≥140mmHg and/or a diastolic blood pressure of ≥90mmHg through three different blood pressure measurements. If the systolic blood pressure is ≥140mmHg and the diastolic blood pressure is < 90mmHg, it is called isolated systolic hypertension (ISH), which usually occurs in old age. Both systolic blood pressure and diastolic blood pressure increase, which is called mixed hypertension, and it is mostly inherited from middle-aged hypertension.

At present, there are more than 54.5 million elderly hypertensive patients in China, and the number continues to increase. The main reasons for the increase are:

② The prevalence of hypertension among the elderly in China is increasing. In 1991, the national hypertension sampling survey showed that the prevalence of hypertension among people aged 64-74 was 41.9%. From 2000 to 2001, a sampling survey of hypertension among people in 12 provinces and cities in China showed that the prevalence rate of hypertension among people aged 64-74 was 48.8%, an increase of 16.5% compared with 1991. The huge number of elderly patients with hypertension in China makes the national medical resources and the prevention and treatment of cardiovascular and cerebrovascular diseases face severe challenges.

The regional differences in the prevalence of hypertension among the elderly do not show the characteristics of "high in the north and low in the south". The prevalence of hypertension among elderly women is close to or even higher than that of men, but the gender difference among the elderly over 80 years old is narrowing.

Research reports show that isolated systolic hypertension accounts for 47.4%~74.8% in elderly hypertensive patients, which is a remarkable feature of elderly hypertension. And with the increase of age, ISH gradually increased, while mixed hypertension decreased.ISH in the elderly is mainly caused by the decrease of compliance due to atherosclerosis of aorta.

Studies have shown that reducing aortic compliance by 35% can increase systolic blood pressure by 25mmHg and decrease diastolic blood pressure by 12mmHg. Because systolic blood pressure can predict the occurrence of cardiovascular events more accurately than diastolic blood pressure, more attention should be paid to the treatment of ISH in clinic.

The elderly patients with ISH can’t effectively buffer the systolic pressure caused by the increase of intra-aortic pressure when they eject blood, and at the same time, they don’t have enough elastic contraction when they relax, so the diastolic pressure decreases or remains unchanged, which eventually leads to the increase of pulse pressure, which is another feature of elderly ISH.

Pulse pressure reflects the fluctuation of blood circulation and is a reliable index to measure the stiffness of aorta. Increased pulse pressure is an independent risk factor for cardiovascular events and death in the elderly, and its predictive value is greater than systolic blood pressure and diastolic blood pressure.

When the pulse pressure is greater than 65mmHg, the incidence of cardiovascular disease, stroke and peripheral vascular disease increases obviously. For every 10mmHg increase in pulse pressure, the incidence of coronary heart disease increased by 36%, stroke increased by 11%, and the total mortality increased by 16%.

Recent studies have shown that diastolic blood pressure is still the strongest predictor of cardiovascular events in the group under 50 years old; The predictive value of diastolic blood pressure, systolic blood pressure and pulse pressure in 50~59 years old is similar; The pulse pressure of the elderly over 60 years old is the most important predictor of cardiovascular events, and almost all of them are accompanied by an increase in systolic blood pressure.

For the elderly, pulse pressure and systolic pressure have replaced diastolic pressure and become the most important indicators for predicting cardiovascular events.

With the increase of age, the sensitivity of baroreceptor decreases and the function of blood pressure regulation decreases, which makes the blood pressure fluctuation range of elderly hypertensive patients significantly larger than that of non-elderly, especially women and systolic blood pressure. The main influencing factors are:

① Eating:The incidence of postprandial hypotension in elderly hypertensive patients is 48.9%, and that in hospitalized elderly patients is as high as 78.5%. It usually happens 20~80 minutes after breakfast, and the blood pressure generally drops by 20~ 40/10~25mmHg, which is obvious after high carbohydrate diet. Its mechanism may be related to the increase of visceral blood perfusion after meals, the decrease of baroreceptor sensitivity and the insufficient sympathetic nerve tension after meals.

② Body position:Orthostatic hypotension can occur in elderly hypertensive patients when they quickly change from squatting position and lying position to sitting position and upright position, which can be reduced by 80/30mmHg in severe cases, and the recovery time is longer than that of non-elderly people. It is mainly related to the decrease of baroreceptor sensitivity in elderly patients;

③ Day and night:The circadian rhythm of hypertension in general elderly patients has not changed significantly, but the blood pressure can fluctuate by 40/20mmHg in one day, reaching 90/40mmHg in some cases, which is easy to be mistaken for pheochromocytoma.

④ Season:The blood pressure of 1/3 elderly patients changes seasonally, and the systolic blood pressure can fluctuate (61 36) mmhg within one year, which is usually low in summer and high in winter. The blood pressure of the elderly fluctuates widely, which not only affects the overall level of blood pressure and the evaluation of therapeutic effect, but also requires special caution in drug selection.

The incidence of complications in elderly patients with hypertension was 40.0%, which was significantly higher than that in non-elderly patients (20.4%). With the progress of the disease, blood pressure continues to rise, causing damage to target organs and eventually leading to various complications.

① Complications related to hypertension itself:Heart failure, cerebral hemorrhage, hypertensive encephalopathy, renal arteriosclerosis, renal failure, aortic dissection;

② It is related to accelerating atherosclerosis:Coronary heart disease, transient ischemic attack, cerebral infarction, renal artery stenosis, peripheral vascular disease. The occurrence of these complications is closely related to blood pressure. When systolic blood pressure rises by 10~12mmHg or diastolic blood pressure rises by 5~ 6mmHg, the risk of stroke increases by 35%~40%, and acute coronary syndrome increases by 20%~25%. Compared with those with normal blood pressure, the incidence of heart failure and coronary heart disease in elderly hypertensive patients is 2 times higher and 3 times higher.

White-coat hypertension refers to the phenomenon that patients only measure blood pressure rise in the clinic and blood pressure outside the clinic is normal, also known as "clinic hypertension".

White coat hypertension accounts for about 20% of primary hypertension, which is more common in elderly patients with systolic hypertension. About 42% of elderly patients with systolic hypertension have normal ambulatory blood pressure monitoring.

The vascular compliance of the elderly decreases, the systolic blood pressure reactivity increases due to stress reactions such as tension, and the sensitivity of baroreceptors decreases due to the increase of blood pressure fluctuation, which makes it more prone to "white coat phenomenon". The incidence of ISH in women is 43% higher than that in men, which may be related to the "white coat phenomenon" among women. 24-hour ambulatory blood pressure monitoring can identify "white coat phenomenon".

The elderly patients with hypertension still have the problem of pseudohypertension (PHT). The reports about senile pseudohypertension at home and abroad are basically the same, and the detection rate is about 50%. Pseudohypertension means that the blood pressure measured by conventional cuff manometry is higher than that directly measured by arterial puncture. Most scholars believe that PHT can be diagnosed if the systolic pressure and/or diastolic pressure measured by cuff pressure measurement are 10mmHg higher than those measured by direct pressure measurement. Clinically, PHT includes three different situations:

① The first case is that the direct pressure measurement is completely normal, but the cuff pressure measurement is higher than normal, which is a simple PHT；;

② In the second case, the direct pressure measurement is higher than normal, but the cuff pressure measurement is higher, and the appearance of PHT cannot rule out the real hypertension, which is PHT phenomenon;

③ The third case is that the direct pressure measurement is completely normal, and the cuff pressure measurement is also normal, but the latter is more than 10mmHg higher than the former, which is also a PHT phenomenon. But what we usually call PHT refers to the first two situations.

Pseudohypertension in the elderly is related to arteriosclerosis, which reflects the degree of arteriosclerosis to some extent. If it is found that the reading of blood pressure in the elderly is high, but there is no target organ involved, and the peripheral blood vessels lack elasticity during palpation, PHT should be highly suspected. Its clinical significance lies in: if the elderly with normal blood pressure have PHT phenomenon, drug antihypertensive treatment may bring serious side effects; However, if PHT exists in elderly hypertensive patients, the severity of hypertension will be overestimated and may lead to over-treatment.

Among the patients who failed to meet the standard after systematic drug treatment, the elderly accounted for 68%, suggesting that the treatment of hypertension in the elderly is more difficult than that in the non-elderly. Among the elderly patients, 58% failed to meet the standard, and most of them were ISH. Combined medication can make the systolic blood pressure and diastolic blood pressure reach the standard of 60% and 90% respectively, indicating that it is more difficult to control systolic blood pressure. Compared with diastolic blood pressure, systolic blood pressure is a more important risk factor. Hypertension in the elderly often coexists with diabetes, hyperlipidemia, atherosclerosis, prostatic hypertrophy, renal insufficiency and other diseases. These diseases interact with each other, which complicates the treatment of hypertension in the elderly.

Most of them are caused by serious complications caused by target organ damage. Such as cerebrovascular accident, coronary heart disease, myocardial infarction, heart failure and renal failure.