Hypertension - Invisible enemy

By TAN SHIOW CHIN
starhealth@thestar.com.my

Leading an active lifestyle does not mean that you do not have high blood pressure. Prof Chia (left) advises adults to get their blood pressure checked at least once a year.

In conjunction with World Hypertension Day last Friday, we take a look at this widespread, insidious disease.

MANY of us have probably in recent weeks frequently experienced symptoms of increased detectable heartbeats (known as palpitations), accelerated breathing and muscle tension, due to stress, excitement or agitation caused by our recent general elections.

Although you would not have felt it, your blood pressure would also have risen during those occasions.

If you are otherwise healthy, your body would have adjusted it back to the average normal of around 120/80 mmHg once the source of the stress, excitement or agitation was removed.

But if you are one of the 32.7% of Malaysians above 18 who have hypertension, then your blood pressure would remain elevated, slowly causing more problems for your body.

Most patients require two to three drugs to control their hypertension.

Hypertension, or high blood pressure, is a very insidious disease.

You can have it and not know it. In fact, you can appear to be perfectly healthy on the outside and still suffer from it, unaware of your condition until one day a stroke or heart attack hits you like lightning out of a clear sky.

This was exactly what one of Prof Datin Dr Chia Yook Chin’s patients experienced.

“The other day, a taxi driver came in (to my clinic). He was 60-plus and led a very active lifestyle.
“He didn’t know that he had hypertension until he suddenly had a stroke.

“When I asked him when was the last time he had visited the doctor (before the stroke), he said, around 30 years ago, so he was obviously quite healthy otherwise,” she says.

The Malaysian Society of Hypertension president and Universiti Malaya Department of Primary Care Medicine senior consultant also shares some frightening statistics from the 2006 National Health and Morbidity Survey (NHMS):

·42.6% of Malaysian adults aged 30 and above have hypertension.
·64% of these people did not know that they had hypertension, ie they were previously undiagnosed.
·Of those who were previously diagnosed, 87.7% were on treatment.
·Of those being treated, only 26% had achieved the target blood pressure of below 140/90 mmHg.

“This means that almost one in every two Malaysian adults are walking around with high blood pressure, and two-thirds of them don’t even know they have it!” says Prof Chia.

In addition, 12.3% of those who know that they have hypertension are not being treated for it, likely due to their own personal choice and/or lack of understanding about the condition.

The most worrying statistic however, is the fact that 74% – almost three-quarters – of hypertension patients being treated are still unable to get their blood pressure under control.

Prof Chia cautions that while previously, normal blood pressure for those above 60 years of age was considered to be 100 mmHg plus their age, this is no longer the case.

“By definition, blood pressure above 140/90 mmHg is deemed to be hypertension. This applies to all those over 30 years of age, including those over 60,” she says.

Invisible effect

Aside from not usually producing any symptoms, hypertension is also particularly dangerous because its ill effects cannot be seen, or even felt, until it is too late.

The constant excessive pounding force against the artery walls eventually damages them, leading to a series of physiological events resulting in arteriosclerosis, where arteries lose their elasticity and become hardened, and/or atherosclerosis, where fats in the bloodstream accumulate at the site of injured artery walls,

Both these conditions result in decreased efficiency of the circulatory system, meaning that less oxygenated blood is getting to our organs, while the heart has to work extra hard to get enough blood circulating throughout the body.

Among the potential consequences of this problem are strokes or transient ischaemic attacks (caused by lack of oxygen to the brain), heart attacks or angina (lack of oxygen to the heart), kidney failure (damage to the kidney’s arteries), erectile dysfunction (lack of blood flow to the penis) and retinopathy (damage to the eye’s arteries).

The overexertion of the heart can also eventually result in heart failure as the heart becomes progressively weaker and less efficient.

Weakened artery walls could also result in an aneurysm – a bulge formed by the high pressure pushing against the weakened artery wall.

Aneurysms are dangerous as they can rupture at any moment without warning, and cause internal bleeding.

The danger with arteriosclerosis, atherosclerosis, and even, aneurysms, is that they can occur in the body without any visible effects, silently wreaking damage until one day they cause a stroke or heart attack.

Hypertensive treatment

According to Prof Chia, most people will need at least two or three medications to control their blood pressure.

She explains that although there are many drugs available to treat hypertension, the first choice for adults with no other health problems would be the angiotensin-converting enzyme (ACE) inhibitors like elanapril and ramipril, and the angiotensin II receptor blockers (ARBs) like losartan and valsartan.

Another class of drugs commonly used is the calcium-channel blockers, which include medications like amlodipine and long-acting nifedipine.

“Usually, we would prescribe an ACE inhibitor or an ARB with a calcium-channel blocker, and these drugs usually work well together,” she says.

If the patient’s blood pressure is still not under control, then the next step would be the prescription of a diuretic, like chorothiazide and metolazone.

“But we don’t always follow this sequence, because the patient might have another problem. For example, we wouldn’t use diuretics in diabetic patients, and for an elderly patient, calcium-channel blockers would be the first choice instead of ACE inhibitors because of clinical evidence,” she says.

In addition, patients have to adopt lifestyle changes like becoming more physically active, reducing salt in their diet, quitting or reducing their alcohol and tobacco consumption, and reducing stress, among others.

Prof Chia stresses that lifestyle changes do help, as diet and exercise can help reduce blood pressure by as much as 10 mmHg.

“For example, say your blood pressure is 145/94, if you do all these things, you might be able to lower your blood pressure to normal without medication, or at least, go another 10 more years without having to go on drugs,” she says, adding that hypertension cannot be cured, but can be normalised in cases like this.

The necessary multi-drug approach to treating hypertension usually brings up patient fears of side effects, but Prof Chia explains that the newer drugs have far fewer side effects than the older ones, and can be taken without fear.

She adds: “What’s good about the latest medications is that they are once-a-day and/or combined pills, which makes it easier for patients to remember to take them.”

Another specific fear she commonly encounters is that the medication might damage the patient’s kidneys.

“For example, I had to add on another drug for a patient the other day, and his first question was, ‘Will it spoil my kidneys?’

“I would like to tell people, blood pressure medications will not ‘spoil’ your kidneys – it is because your blood pressure is high that your kidneys are damaged,” she says.

Hypertension is one of the most common causes of kidney failure, due to the critical role played by blood vessels – which are easily damaged by long-term uncontrolled high blood pressure – in the function of our kidneys.

At the end of the day, Prof Chia strongly emphasises the need for all adults to get their blood pressure checked, regardless of how healthy they think they are, and to treat it properly.

“I think the pay-off of treating hypertension is tremendous; it’s very well worth it in terms of reducing strokes alone.”

Self-monitoring

  Digital sphygmomanometers are becoming increasingly affordable, and more hypertension patients have one at home to regularly monitor their blood pressure.

MALAYSIAN Society of Hypertension president and Universiti Malaya Department of Primary Care Medicine senior consultant Prof Datin Dr Chia Yook Chin believes the lack of symptoms in hypertension is an important reason why blood pressure is not better controlled among Malaysians.

“Some patients feel no symptoms, so they don’t feel that they need to take their medication,” she says.

There are also patients who modify their drug intake, such as cutting down their dosage or dispensing with one drug if they are on more than one medication, once they perceive their blood pressure is under control.

Prof Chia shares that this is one of the fears of doctors when they ask patients to monitor and record their blood pressure daily.

She stresses: “If your blood pressure is normal on medication, that means you are taking the right amount of drugs!

“Any level you can get down to is okay, unless you experience side effects such as feeling giddy or light-headed upon standing up. We would only be more concerned (about low blood pressure) in elderly patients who also have other health problems.”

She cautions that once patients stop taking their medications or lower their dosage without their doctor’s approval, their blood pressure will immediately start climbing up again, even though they may not detect it immediately.

For those who do home monitoring with digital sphygmomanometers (blood pressure meters), Prof Chia’s advice is to use those with the upper armcuff, rather than those measuring from the wrist or finger, as the armcuff provides the most accurate measurement.

In addition, they should try to buy machines that have been validated by the non-profit British Hypertension Society (listed here: www.bhsoc.org//index.php?cID=246).

She adds that digital sphygmomanometers tend to be less accurate than their mercury counterparts, giving slightly lower readings.

“So, if your (digital) reading is close to 140/90 mmHg, you can take it as hypertension,” she says.
 
Classifying hypertension

HYPERTENSION is classified into two categories according to its cause: essential and secondary.

The vast majority of patients have essential or primary hypertension, while only about 5-10% of patients have secondary hypertension, which are mainly caused by kidney and hormonal conditions like renal artery stenosis, hyperthyroidism, Cushing’s syndrome, and even pregnancy, among others.

The exact cause of essential hypertension is still unknown, although it is certainly the result of a combination of factors, including increasing age, having relatives with high blood pressure (ie family history), a sedentary lifestyle, a poor diet with too much salt, drinking too much alcohol, smoking and too much stress.

Says Malaysian Society of Hypertension president and Universiti Malaya Department of Primary Care Medicine senior consultant Prof Datin Dr Chia Yook Chin: “Each factor increases blood pressure by just a little, but when you add them all together little by little, it raises it by quite a lot.”

Despite not knowing the root cause of hypertension, it has been established that there is overstimulation of the sympathetic nerves in people with this condition.

This in turn increases the secretion of certain hormones involved in the regulation of sodium and fluids in the body, called renin, angiotensin, and aldosterone.

The amount of salt and water in our body affects our blood pressure – the more salt and water present, the higher our blood pressure.

These two elements are regulated by our kidneys through the three hormones mentioned above, which are produced by the adrenal glands located on top of the kidneys.

The overstimulation of the sympathetic nerves also results in increased vascular tone, which causes our arteries to become constricted, thus, also raising blood pressure.

Understanding blood pressure

BLOOD pressure is created from the passage of blood through our arteries – the blood vessels through which blood flows from the heart to the rest of the body.

As our blood pours through these thick tube-like structures, it exerts a force against the artery walls known as blood pressure.

Blood pressure is measured by two numbers: systolic blood pressure and diastolic blood pressure.
Systolic blood pressure represents the peak pressure in our arteries, which occurs during the contraction of the heart, also known as systole.

Meanwhile, diastolic blood pressure is the minimum blood pressure in the arteries, which occurs when the heart relaxes during diastole.

Blood pressure is measured in millimetre mercury (mmHg), and the normal average reading is 120 (systolic)/80 (diastolic) mmHg.

You are considered to have hypertension when your blood pressure is 140/90 mmHg or more, while the range between these two readings is considered pre-hypertension.

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