Hypertension

Measuring the blood presure. Source: WHO photo by T. Farkas, National Library of Medicine.

Hypertension is also known as high blood pressure. Blood pressure is the force of the blood pushing against the walls of the arteries measured in millimeters of mercury (mmHg). The systolic pressure (pumping pressure)is recorded on top of or in front of the diastolic pressure (resting pressure). Normal blood pressure is 120/80 mmHg. Hypertension is a serious condition that can lead to coronary heart disease, heart failure, stroke, kidney failure, and other health problems.

Other names

• High blood pressure
• HBP
• HTN

Types

Essential

Essential or primary hypertension refers a persistent and pathologic elevation in the blood pressure in which no identifiable cause can be found.

Secondary

Secondary hypertension is elevated blood pressure that results from an underlying, identifiable, often correctable cause. Only about 5-10% of hypertension cases are thought to result from secondary causes. ^[1]

Signs and Symptoms

Hypertension (HTN) itself usually has no symptoms. Thus, it has been called 'the silent killer'. Rarely, headaches may occur. Some people only learn that they have HTN after the damage has caused problems.

Causes

As stated earlier, most cases of hypertension are essential and have no identifiable cause. The most causes, when identified, include:

• Abnormalities of the kidneys including renovascular disease (renal artery stenosis)
• Disorders of the adrenal glands, such as hyperaldosteronism, Cushing syndrome, pheochromocytoma or an adrenal tumor.
• Certain congenital heart defects
• Sleep apnea
• Medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers like ibuprofen, and corticosteroids
• Illegal drugs, such as cocaine and amphetamines
• Alcohol abuse
• Tobacco use
• Caffeine (especially heavy intake)
• Pregnancy (preeclampsia)

Diagnosis

Hypertension is diagnosed using the results of blood pressure tests. These tests will be done several times at different times of the day to make sure the results are correct. If the blood pressure readings are consistently elevated, more tests are usually done to determine the cause of the hypertension (and to rule out any treatable causes).

Prehypertension is a systolic pressure ranging from 120 to 139 mm Hg or a diastolic pressure ranging from 80 to 89 mm Hg. The blood pressure readings do not meet absolute criteria for the diagnosis of hypertension, but typically, within four years of being diagnosed with prehypertension, nearly one-third of adults ages 35 to 64 and nearly half the adults age 65 or older develop high blood pressure. ^[2]

Stage 1 hypertension is a systolic pressure ranging from 140 to 159 mm Hg or a diastolic pressure ranging from 90 to 99 mm Hg.

The most severe hypertension, stage 2 hypertension is a systolic pressure of 160 mm Hg or higher or a diastolic pressure of 100 mm Hg or higher.

Exams and tests

Tests done to evaluate hypertension include:

• Urinalysis to look for blood and protein as evidence of hypertensive kidney damage
• Blood chemistry tests of kidney function, electrolytes, and fasting blood sugar
• Fasting lipid panel including total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides, to look for additional cardiac risk factors
• Electrocardiogram (ECG) to look for evidence of damage to the heart muscle, as well as evidence of ischemic heart disease, arrhythmia, and other potential consequences of hypertension
• Fundoscopic examination of the retina and retinal blood vessels to look for hypertensive changes

Treatment

Usually, the initial treatment for hypertension, especially if it is stage 1 or prehypertension, is to make any necessary lifestyle changes. These may include:

• Following a healthy eating plan
• Doing enough physical activity
• Maintaining a healthy weight
• Quitting smoking
• Managing stress and learning to cope with stress

Medications

Today’s blood pressure medicines can safely help most people control their blood pressures. These medicines are easy to take. The side effects, if any, tend to be minor.

Blood pressure medicines work in different ways to lower blood pressure. Some remove extra fluid and salt from the body to lower blood pressure. Others slow down the heartbeat or relax and widen blood vessels. Often, two or more medicines work better than one.

The major classes of blood pressure medications are:

Diuretics

Diuretics are sometimes called "water pills". They help the kidneys flush excess water and salt from the body, thus lessening the amount of fluid in the blood, and lowering intravascular volume status and ultimately the blood pressure.

Diuretics often are used in combination with other hypertension medicines and sometimes combined into one pill.

Beta Blockers

Beta blockers help the heart beat slower and with less force. The heart pumps less blood through the blood vessels, and the blood pressure is lowered. This class of medicine works better in some groups of people when combined with a medication from another class.

ACE Inhibitors

Angiotensin-converting enzyme (ACE) inhibitors keep the body from making a hormone called angiotensin II. This hormone normally causes blood vessels to narrow. ACE inhibitors prevent this, thus lowering the blood pressure.

Angiotensin II Receptor Blockers

Angiotensin II receptor blockers (ARBs) are newer blood pressure medicines that protect the blood vessels from angiotensin II. As a result, blood vessels relax and widen, and the blood pressure goes down.

Calcium Channel Blockers

Calcium channel blockers (CCBs) keep calcium from entering the muscle cells of the heart and blood vessels. This allows blood vessels to relax (vasodilate), and the blood pressure to lower.

Alpha Blockers

Alpha blockers reduce nerve impulses that tighten blood vessels. This allows blood to flow more freely, causing blood pressure to go down.

Alpha-Beta Blockers

Alpha-beta blockers reduce nerve impulses the same way alpha blockers do. However, they also slow the heartbeat like beta blockers. As a result, blood pressure goes down.

Nervous System Inhibitors

Nervous system inhibitors increase nerve impulses from the brain to relax and widen blood vessels.

Vasodilators

Vasodilators relax the muscles in blood vessel walls, opening the vessels and allowing blood pressure to decrease.

Direct Renin Inhibitors

Holistic and alternative treatments

Dietary supplements which have been reported to lower blood pressure include: Although diet and exercise are the best tactics to lower your blood pressure, some supplements also may help decrease it. These include:

• Alpha-linolenic acid
• Calcium
• Cocoa
• Cod-liver oil
• Coenzyme Q-10
• Omega-3 fatty acids
• Garlic
• Psyllium

Some supplements can interact with medications, causing harmful side effects. Any use of supplements should be discussed with a healthcare provider. A particular supplement may not have been adequately studied for risks and benefits, so any claims should be carefully examined.

Yoga or deep breathing and/or biofeedback may help with relaxation and reduction of stress. These practices may have a positive effect on hypertension.

Practical treatment

It is still a matter of debate which is the first-line drug to use when lifestyle measures do not provide satisfactory control of blood pressure. Looking at the majority of evidences from clinical studies diuretics should be used as first-line agents, but other antihypertensive drugs may be also appropriate in special clinical conditions and comorbidity. The debate about which is the most preferable drug to use as first line agent is often overcome in clinical practice by the need to use more than one drug to control blood pressure. The benefits of controlling hypertension are independent from the level of high blood pressure registered before the beginning of treatment. The most important goal is to control the high blood pressure using those agents well accepted and tolerated by the patients in order to achieve a good compliance and an acceptable control of hypertension, in order to avoid the main complications. On the basis of current evidence blood pressure, both systolic and diastolic, should be lowered at least below 140/90 mmHg in all hypertensive patients, and below 130/80 mmHg in diabetics. However estimation of global cardiovascular risk should guide the treatment.

Prevention

Enacting any of the lifestyle changes listed above (losing weight, quitting smoking, controlling diabetes, evaluating any medication taken) may prevent hypertension.

Being compliant with lifestyle changes and a treatment program will hopefully keep the blood pressure in the normal range and prevent any complications from hypertension.

Living with Hypertension

Hypertension is a lifelong condition that usually has no specific cause and therefore no cure. This means making lifestyle changes, taking prescribed medicines, and ensuring regular medical check-ups will need to be continued for life.

Women with hypertension will likely need closer monitoring during pregnancy. With good compliance and ongoing care, many women with high blood pressure have healthy pregnancies.

Chances of Developing Hypertension

In the United States, about 72 million people have high blood pressure (HBP). This is about 1 in 3 adults. ^[3]

The National Heart Lung and Blood Institute's report on prevention, detection, evaluation and treatment of high blood pressure summarizes the incidence of high blood pressure by gender, ethnic group, and income level. ^[4]

Risk factors

The following are risk factors for hypertension according to the National Heart Lung and Blood Institute ^[4]:

Older Age

Blood pressure tends to rise with age. Isolated systolic hypertension (ISH) is the most common form of HBP in older adults. ISH occurs when only systolic blood pressure (the top number) is high. About 2 out of 3 people over age 60 who have HBP have ISH.

Race/Ethnicity

HBP can affect anyone. However, it occurs more often in African American adults than in Caucasian or Hispanic American adults. In relation to these groups, African Americans:

• Tend to get HBP earlier in life
• Often have more severe HBP
• Are more likely to be aware that they have HBP and to get treatment
• Are less likely than Caucasians and about as likely as Hispanic Americans to achieve target control levels with HBP treatment
• Have higher rates than Caucasians of premature death from HBP-related complications, such as coronary heart disease, stroke, and kidney failure

HBP risks vary among different groups of Hispanic American adults. For instance, Puerto Rican American adults have higher rates of HBP-related death than all other Hispanic groups and Caucasians. But, Cuban Americans have lower rates than Caucasians.

Overweight or Obesity

Prehypertension or HBP is more likely in people who are overweight or obese. Overweight is having extra body weight from muscle, bone, fat, and/or water. Obesity is having a high amount of extra body fat.

Gender

Fewer adult women than men have HBP. But, younger women (aged 18–59) are more likely than men to be aware of and get treatment for HBP.

Women aged 60 and older are as likely as men to be aware of and treated for HBP. However, among treated women aged 60 and older, blood pressure control is lower than it is in men in the same age group.

Unhealthy lifestyle habits

A number of lifestyle habits can raise the risk for HBP, including:

• Eating too much sodium (salt)
• Drinking too much alcohol
• Not getting enough potassium in the diet
• Not doing enough physical activity
• Smoking

Other Risk Factors

• A family history of HBP raises the risk for the condition.
• A history of prehypertension also increases the risk of developing hypertension
• Long-term stress may increase the risk of HBP

Risk Factors for Children and Teens

Overweight is on the rise in youth younger than 18 years. As a result, prehypertension and HBP also are becoming more common in this age group.

African American and Mexican American youth are more likely to have HBP and prehypertension than Caucasian youth. Also, boys are at higher risk for HBP than girls.

Like adults, children and teens need to have routine blood pressure checks. This is even more important if a young person is overweight.

Related Problems

High blood pressure is often called the ‘silent killer’ because it usually has no noticeable warning signs or symptoms until other serious problems arise. Therefore, many people with high blood pressure do not know that they have it. High blood pressure is a major risk factor for heart disease, the leading cause of death in the United States. It can lead to hardened or stiffened arteries, which causes a decrease of blood flow to the heart muscle and other parts of the body. Reduced blood to the heart muscle can lead to angina (chest pain or damage to the heart muscle due to a lack of blood carrying oxygen to the heart muscle) or to a heart attack (caused by a chronic spasm or blockage of blood and oxygen to the heart).

High blood pressure is a major risk factor for heart failure, a serious condition where the heart cannot pump enough blood for the body’s needs. It is also the major risk factor for stroke, which is the third leading cause of death in the United States. A stroke may be caused by a rupture or blockage of an artery that supplies blood and oxygen to the brain.

In addition, high blood pressure can result in damage to the eyes, including blindness. The blood vessels in the eyes can rupture or burst from high blood pressure leading to impairment of sight.

High blood pressure can also result in kidney disease and kidney failure. The kidneys filter wastes from fluids in the body. High blood pressure can thicken and narrow the blood vessels of the kidneys, resulting in less fluid being filtered and wastes building up in the body. Also, diseases of the kidney can be a cause of high blood pressure.

Clinical Trials

There are many ongoing clinical trials in the U.S. A list is available at ClinicalTrials.gov: hypertension trials

Research

Recent discoveries

• A study done to assess blood pressure response and time to achieve blood pressure goals in a diverse population of hypertensive patients treated with hydrochlorothiazide, valsartan, or a combination showed that compared with monotherapy, combination therapy resulted in greater reductions in BP and achievement of goal BP in a shorter period of time. ^[5]
• A recent study from China concluded that depression and anxiety were possibly associated with hypertension and more attention needs to be paid to the mental health situation of hypertensive patients in order to improve their quality of life. ^[6]
• Another study from the same Chinese group observed whether the community-based management for patients with hypertension can reduce the incidence of stroke. They concluded that long-term follow-up and management for patients with hypertension, and control of the blood pressure could significantly reduce the incidence of stroke. ^[7]
• A recent study published in the journal Pediatrics indicated that the rate of progression of prehypertension to hypertension in adolescents was approximately 7% per year. Prehypertension can be predictive of future hypertension and may benefit from preventive interventions, especially lifestyle changes. ^[8]

Current research

• The long-term safety and efficacy of the CVRx Rheos Baroreflex Hypertension Therapy System is being evaluated in patients who participated in the DEBuT-HT study. ^[9]
• The Danish Hypertension Prevention Project - (DHYPP) is evaluating subjects 18 to 36 years of age whose parents both have essential hypertension. The subjects receive treatment with either the AT1-antagonist candesartan cilexetil, 16 mg daily or placebo for one year. Then, treatment is withdrawn and the subjects is followed for 10 years to determine if the treatment has been able to either prevent or delay the development of hypertension. ^[10]
• An assessment of the long-term safety and tolerability of the combination of aliskiren and valsartan (300 mg/ 320 mg) in patients with high blood pressure,followed by assessment of long-term safety and tolerability of the combination of aliskiren/valsartan/HCTZ. ^[11]
• The ability of olmesartan medoxomil to lower the blood pressure of patients 65 years of age or older with high blood pressure is being studied. The medication being tested has been approved by the FDA for the treatment of high blood pressure. ^[12]
• Another study is assessing the benefits and risks of treating th very elderly (those aged 80 or older) individuals with hypertension. Indapamide and perindopril are the drugs being used for treatment. ^[13]

Related Videos

This video from NHS Choices addresses hypertension, how it lacks symptoms, and how it can damage the kidneys, heart and brain if not treated:

References

1. ↑ Onusko E. Diagnosing secondary hypertension. Am Fam Physician. 2003 Jan 1;67(1):67-74. Abstract | Full Text
2. ↑ MayoClinic.com. High blood pressure
3. ↑ National Heart Lung and Blood Institute. Diseases and Conditions Index. Who Is At Risk for High Blood Pressure?
4. ↑ ^{4.0 4.1} National Heart Lung and Blood Institute. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure - Complete Report
5. ↑ Nash DT, Crikelair N, Zappe D. Achieving BP goals with valsartan and HCTZ alone and in combination: pooled analysis of two randomized, double-blind, placebo-controlled studies. Curr Med Res Opin. 2008 Aug 6. (Epub ahead of print) Abstract
6. ↑ Han J, Yin XM, Xu F, Hong X, Liang YQ, Wang ZY. A case-control study on depression and anxiety in hypertensive patients. Zhonghua Liu Xing Bing Xue Za Zhi. 2008 Feb;29(2):125-7. Abstract
7. ↑ Ru XJ, Wang WZ, Wu SP, Jiang B, Du XL, Bao QJ. Study on the relationship between hypertension management and the risk of stroke at community level. Zhonghua Liu Xing Bing Xue Za Zhi. 2008 Feb;29(2):116-20. Abstract
8. ↑ Falkner B, Gidding SS, Portman R, Rosner B. Blood pressure variability and classification of prehypertension and hypertension in adolescence. Pediatrics. 2008 Aug;122(2):238-42. Abstract
9. ↑ ClinicalTrials.gov. Device Based Therapy in Hypertension Extension Trial (DEBuT-HET)
10. ↑ ClinicalTrials.gov. Danish Hypertension Prevention Project - DHYPP
11. ↑ Clinicaltrials.gov. A Safety and Tolerability Study of the Combination of Aliskiren/Valsartan in Patients With High Blood Pressure, Followed by Long-Term Safety and Tolerability of Aliskiren, Valsartan and Hydrochlorothiazide.
12. ↑ ClinicalTrials.gov. An Examination of the Blood Pressure Lowering Ability and Safety of Olmesartan Medoxomil in Elderly Patients With Hypertension
13. ↑ ClinicalTrials.gov. The Hypertension in the Very Elderly Trial (HYVET)

External Links

National Hypertension Association

American Heart Association

American Society of Hypertension, Inc. (USA)