Hypertension

High BP is one of the 3 main risk factors for heart attack and stroke.

The other risk factors are smoking and raised blood cholesterol levels.

Lowering blood pressure ( and lowering blood cholesterol) saves lives.

If your blood pressure is consistently over 160/90mmHg, your doctor would tell you that you have hypertension. But generally speaking, the lower your blood pressure, the better. If your pressure is between 140/90 and 160/90mmHg, then you may be diagnosed as having ‘border line’ hypertension. Blood pressure readings are a remarkably accurate predictor of life expectancy: the higher the pressure, the greater the risk of heart disease than people with lower than average levels.

For this reason, it has been extremely difficult to find a working definition of hypertension. Perhaps the most sensible view is to define it as ‘that level of blood pressure where treatment with anti-hypertensive drugs does more good than harm’, because there is no such thing as drug treatment that does not have some potential side effects.

If your BP is found to be more than 160/90 mmHg, and if you have several different risk factors for heart disease, such as high cholesterol, being a smoker and a family tendency to heart disease, then treating your high BP is likely to be very worth-while. On the other hand, for some young people with only marginally raised blood pressure, and no other risk factors for heart disease, the value of BP lowering drugs is very small and drug treatment may therefore be held back. However it is however, crucial that such people are re-checked at regular intervals of about 6 months.

Hypertension has been called the ‘silent killer’ because it usually causes no symptoms until a late stage of the disease, contrary to what many people believe, it is not possible to feel you own blood pressure. The only way to find out whether your blood pressure is raised is to have it measured with a BP machine. As BP causes no symptoms until complications begin to show themselves, about half of all individuals who have it remain unaware that they have a problem.

WHY HYPERTENSION MATTERS:

Blood vessels are like rubber tubes that carry blood constantly to wherever it is needed. Arteries have to withstand the great pressures with which the blood is pumped out of the heart. If the BP is higher than usual over many years, as in untreated hypertension, the vessel gets damaged. The lining of the arteries can become rough and thick, and this eventually causes them to narrow and become less flexible, or elastic, than previously, this is known as arteriosclerosis. If an artery becomes too narrow, Blood cannot get through properly, and the part of the body that relies on that artery for its blood supply is starved of blood and the all important oxygen that it carries. As the artery narrows there is an increased tendency to develop blood clots (thrombosis), which may cause total blockage of the artery so that the part of the body that it serves dies, If the heart or the brain is affected, the dead area is called an infarct.

OTHER RISK FACTORS: High BP over many years can cause health problems, and the whole point of measuring BP regularly, and treating it effectively if it is high, is to prevent these complications. However, you are more likely to develop these complications if you smoke and if you have untreated high blood cholesterol levels. The reason is that smoking damages blood vessels in much the same way as high BP, making them narrower and their lining thick and rough. High cholesterol can cause fatty deposits called arthromeres in the lining of the artery to develop more rapidly than normal, which also helps to narrow the arteries. It is not possible for your level of serum cholesterol to be too low, and treatment to lower cholesterol saves lives. Another common risk factor that can also contribute to narrowing of the arteries is diabetes (diabetes mellitus), which affects 4 to 5 percent of the population and a greater proportion of the indigenous population. High glucose levels in the blood damage arteries in a similar way as high BP. But it would not do to paint too gloomy a picture.

Its better to have your BP checked than feel sorry at a later stage:

The whole point of having your BP checked is that if you are found to have hypertension, it is possible to treat it effectively and thus bring down to normal. It does not matter particularly how severe the hypertension was in the first place. What is really important is how well your blood pressure is controlled over the ensuing years. It is better to have had severe hypertension that has been well treated than to have slightly raised blood pressure that remains untreated or neglected.

LONG TERM EFFECTS OF HIGH BLOOD PRESSURE:

The heart is a muscle that needs its own blood supply, which is brought to it by the coronary arteries. If these arteries are narrow, blood does no get to the heart muscle efficiently, the heart needs to work a bit. Harder than usual, E.g when your walking up a hill the heart muscle cannot get the blood supply and oxygen that it needs. This causes pain in the chest, known as myocardial is chaemia or angina. If a coronary artery narrows and then a blood clot forms, the part of the heart muscle that relies on that coronary artery dies.

This is known as coronary thrombosis, a myocardial infarction or a heart attack.

Over the years, as arteries narrow and become less elastic as a result of hypertension, it gets harder and harder for the heart to pump blood out efficiently to he rest of the body. The increased work load eventually damages the heart and impairs it’s performance. Fluid collects in the lungs, causes shortness of breath. This is known as congestive cardiac failure.

Narrowing of an artery that carries blood and oxygen to the brain can lead o temporary loss of function in he part of the brain served by that artery, this is known as Transient Ichaemic Attack (TIA). Permanent closing off of the artery with a blood clot results in the death of the part of the brain reliant on that artery, which results in a stroke.

Smaller blood vessels in the legs can be damaged, resulting in the legs getting damaged, resulting in less blood getting to the feet and pain in the calf muscles on walking.

When blood vessels supplying the kidneys are affected, the result may be gradual kidney damage. This is why a blood test to check kidney function is a vital part of regular check ups for any one with hypertension.

The small blood vessels in the eyes can also be affected, although this may not become apparent until the damage is extensive. Rarely, in severe hypertension there may be damage to the retinal with haemorrhages. This condition is called malignant hypertension, although with treatment the outlook is very good.