INTRODUCTION TO HYPERTENSION

The heart pumps oxygen-rich blood into the arteries (blood vessels), which then carry the blood throughout the body. Blood pressure is the measurement of the force of blood pushing against the arterial walls. The only way to know your blood pressure is to have it measured by your doctor.

Two numbers are used to describe blood pressure. Both are a measurement of the force of the blood against arterial walls.

• The top number is called the systolic blood pressure, which indicates the pressure of the blood against the arteries when the heart contracts to pump blood. It is a measure of blood pressure when the heart beats.
• The bottom number is called the diastolic blood pressure, which indicates the pressure of the blood against the artery walls when the heart is resting in between beats. It indicates the elasticity of the arteries.

When blood pressure is recorded, the systolic pressure is always recorded first, followed by a diagonal line and the diastolic pressure. If a person has a blood pressure of 118/78mmHg, it means that the patient has a reading of 118 systolic and 78 diastolic blood pressures. The unit of measure of blood pressure is in millimeter mercury and it is usually written as mmHg.

How Do I Know If I Have Hypertension?

High blood pressure usually does not cause symptoms, that's why it is referred to as the "silent killer". Vital organs and tissues of the body can be damaged by high blood pressure without any symptoms. Occasionally, extreme levels of high blood pressure can cause the following symptoms:

• Headaches, especially pulsating headaches behind the eyes that occur early in the morning
• Visual disturbances
• Nausea and vomiting

• Having blood pressure reading on different occasions is consistently equal to or higher than 140/90mmHg.

Measuring the Blood Pressure

Blood pressure should be measured in a standard manner and the equipment used must meet certification criteria.

The following techniques are recommended :

1. The patient should be seated on a chair with their backs supported and their arms bared and supported at heart level. They should not smoke or ingest caffeine during the 30 minutes preceding the measurement.
2. The patient should rest for 5 minutes before blood pressure is taken. An appropriate cuff should be used. The bladder within the cuff should encircle at least 80 percent of the arm.
3. Measurements should be taken with a mercury sphygmomanometer. A recently calibrated aneroid manometer or a validated electronic device can be used. Finger monitors are not acceptable. Blood pressure devices used for home measurement should be checked periodically by comparing readings with simultaneous readings taken with a mercury device.Now, digital blood pressure monitor had been developed to measure blood pressure in a more convenient way.
   

Both the systolic (SBP)and diastolic (DBP)blood pressure is recorded. The first appearance of sound is taken as SBP and the disappearance of sound is the DBP.

Classifications of Hypertension

Hypertension is divided into primary hypertension where there is no identifiable cause and secondary hypertension where a cause can be determined.
The following classification of raised blood pressure is taken from The Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood pressure (JNC VI). It defines the grades of blood pressure according to its severity. It is based on blood pressure for adults aged 18 and older who are not on treatment for high blood pressure.

Category	Systolic (mm Hg)		Diastolic (mm Hg)
Optimal	<120	and	<80
Normal	<130	and	<85
High normal	130-139	Or	85-89
Hypertension
Stage 1	140-159	Or	90-99
Stage 2	160-179	Or	100-109
Stage 3	>=180	Or	>=110

Causes of Hypertension

9 out of 10 people who have hypertension do not have apparent reason for it. However there are certain groups of people who are at higher risk. People who are overweight, smoke, eat salty and fatty regularly, physically inactive or suffer frequent stress are generally at a higher risk of developing high blood pressure.

People who have a family history of hypertension are also more likely to develop hypertension. There are also less common causes of hypertension due to disorders of the kidney and endocrine glands.

Complications of Hypertension

People who have hypertension, which is not treated, are at higher risk of developing cardiovascular complications such as heart attacks, heart failure, kidney damage and stroke compared to people with normal blood pressure.

This risk can be higher if a hypertensive patient has other medical conditions such as:

• Obesity People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure.
• High dietary sodium (salt) increases blood pressure in some people.
• Heavy and regular use of alcohol can increase blood pressure dramatically.
• Lack of physical activity People who are inactive have a 30-50% greater risk of developing high blood pressure.(1)
• Stress (although responses to stress vary from person to person)
• Race Blacks develop high blood pressure more often than whites, and it tends to occur earlier and be more severe.
• Heredity If your parents or other close blood relatives have high blood pressure, you're more likely to develop it.
• Age In general, the older you get, the greater your chance of developing high blood pressure. It occurs most often in people over age 35.
• Gender Men are more likely to develop high blood pressure between age 35 and 55.
• Women are more likely to develop it after menopause.

How to Treat Hypertension and Why?

How is Hypertension treated?
Hypertension can be controlled by life style changes or if necessary by medication. Very often losing weight, exercising, eating less salt, quitting smoking and avoiding excessive alcohol is all you need to control your blood pressure. When changing lifestyle does not help control blood pressure, the doctor may prescribe medications. Even when taking medication, one should continue the healthy lifestyle, as it will help to control blood pressure more effectively.


Why treat Hypertension?
Untreated hypertension has been associated with increased risk of strokes, heart and kidney failure. An elevated blood pressure has been correlated to shortened life span in some studies. Awareness of the condition and subsequent treatment has reduced death and morbidity due to hypertension. The age adjusted death rates from strokes declined by 60% and the death from coronary heart disease fell by 53% among men and women of African American descent and amongst whites.

ANTIHYPERTENSIVE DRUGS

The anti-hypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Evidence suggests that reduction of the blood pressure by 5 mm Hg can decrease the risk of stroke by 34%, of ischaemic heart disease by 21%, and reduce the likelihood of dementia, heart failure, and mortality from cardiovascular disease.

There are many classes of anti-hypertensives, which lower blood pressure by different means; among the most important and most widely used are

· thiazide diuretics

· ACE inhibitors

· calcium channel blockers

· beta blockers

· angiotensin II receptor antagonists or ARBs.

Which type of medication to use initially for hypertension has been the subject of several large studies and resulting national guidelines? The fundamental goal of treatment should be the prevention of the important endpoints of hypertension, such as heart attack, stroke and heart failure. The several classes of antihypertensives differ in side effect profiles, ability to prevent endpoints, and cost. The choice of more expensive agents, where cheaper ones would be equally effective, may have negative impacts on national healthcare budgets. As of 2009, the best available evidence favors the thiazide diuretics as the first-line treatment of choice for high blood pressure when drugs are necessary.