HIGH BLOOD PRESSURE.

High Blood Pressure is often under treated or over treated – yup!

Blood Pressure - do I really have high pressure & how is it treated?

Who should I see about my raised Blood Pressure?

The GP is a specialist in primary care and thoroughly trained in the diagnosis, investigations and management of hypertension. The decision algorithm for starting medication is reasonably complex.

The most current guidelines are the American JCN8 guideline and The British Hypertension Society/NICE combined hypertension guideline (2013). The Australian hypertension guideline was updated in 2016.

A referral to a sub-specialist is indicated for resistant or secondary hypertension.

Should I check my Blood Pressure?

Measuring your Blood Pressure (BP) at home is a good idea. There is good evidence that home readings are a better reflection of your blood pressure than clinic readings. Home readings better reflect cardiovascular risk than clinic readings.

It has been shown that Home BP readings are on average around 10/5 lower than in a clinic. This is called “white coat” Hypertension when there is a big difference between home and clinic readings. It is normal for the clinic reading to be a bit higher –  you may have been in a car park, waiting room and you may be worried about your blood pressure.

The best Blood Pressure Machines are the one that cover your upper arm (not the wrist). The cuff must be the right size for your arm – too small and the machine will over-read (a common problem).

The BP machine should be accredited – the ones by Omron usually are. Go to this British Hypertension Society website to check which BP machines are accredited. Many of the Omron machine are available in Australia. Nothing fancy is needed – the cheapest of the accredited machine have been shown to give accurate readings.

Measure your blood pressure twice per day for 5 days preferably in the morning and later in the day. For each reading, measure your BP twice at least 1 minute apart and with the arm resting at heart level) – The Blood Pressure is the lowest of the two readings.

Clinic readings are still useful because trials of Blood Pressure Treatment are based on clinic readings.

The first readings is the Systolic reading and represents the highest pressure in the arteries during contraction of the heart. The lower reading is the Diastolic reading and represents the lowest pressure in the artery (between heart contractions). The two readings are separated by a ” / ”

How do I check my Blood Pressure at home?

Measure your blood pressure (BP) twice per day for 5 days preferably in the morning and later in the day. Check your BP twice each time one minute apart and record only the second reading.

The correct way to check your home BP is:

  • After sitting for 5 minutes with no distractions – no TV, no conversation, no stress!
  • At least half an hour after having any coffee/caffeint or cigarette
  • Have Both Feet on the floor and do not cross your legs
  • The upper arm should be supported with the BP machine cuff at the level of your heart

How do I know if I have Hypertension?

Hypertension (High Blood Pressure) is Blood Pressure that is above an optimum level for that person – so the figures vary according to individual circumstances. A slightly raised Blood Pressure might be fine for someone at overall low risk. The same Blood Pressure will be too high for someone with , for example, certain types of Kidney Disease or Diabetes.

This has led to the concept of Grades of Hypertension.

The following figures are based on average home BP readings. Clinic readings are higher.

Grade 1 (Mild Hypertension): 135 to 149/85-95 (average home BP)

Grade 2 (moderate Hypertension): 150/95 or above (average home BP)

Grade 3 (severe Hypertension): The systolic is 180 or more (whatever the diastolic)

How do I know if I have White Coat Syndrome?

White coat Hypertension is simply a raised Blood Pressure in the clinic (greater than 140/90) and a normal Blood Pressure (average less than 135/85) at home. The BP is higher anyway by around 10/5 in the clinic – but this difference is often greater with white coat hypertension.

Clearly, white coat hypertension is not as concerning as “Sustained” hypertension” whioch is what is really being referred to when someone has “Hypertension.”

However, White Coat Hypertension is still a bit of an issue because:

  • Around one third go on to develop sustained hypertension within five years
  • There is an increased risk of Type 2 Diabetes
  • There is an association with impaired glucose tolerance

I reckon around two thirds of patients want to talk whilst having their Blood Pressure checked!Please sit back and relax to avoid an artificially high reading. It’s a hunch that ‘polite’ doctors who let you talk tend to ‘get’ higher Blood Pressure readings.

How is High Blood Pressure Confirmed?

Home BP readings are good both for diagnosis and monitoring.

A 24 hour (Ambulatory) BP machine checks your Blood Pressure over 24 hours, including during sleep. The result will give the best indicator as to state of your blood pressure – even better than home readings. The average blood pressure overnight is also an independent indicator of vascular risk.

It is estimated that 1 in 4 to 1 in 5 people with a diagnosis of hypertension do not have the diagnosis. It must be emphasized that spending money on BP machines and/or 24 hr BP is money is money well spent in the long run.

Spending money on BP machines and/or 24 hr BP is usually money well spent in the long run.

What are the reasons for High Blood Pressure? Are any tests needed?

Either Hypertension is usually “Primary” (just how your body works – Biological) or maybe “Secondary” to an underlying disease.

Tests at the initial diagnosis are for two reasons:

  • To check for any damage caused by the High Blood Pressure: ECG, urine & Eye check
  • To rule out any Secondary causes of Hypertension

Most of the secondary causes are very rare (Phaeocromocytoma) but the more common causes are:

  • Renal Artery Stenosis (RAS): The test is a renal Doppler (imaging study) or MR/CT Angiography. There are two types of RAS – muscular thickening that occurs at a younger age, and fatty plaques (atheroma) in those with vascular risk factors. The fibromuscular thickening may be treated with an angioplasty procedure.
  • Chronic Kidney Disease: Blood test & Urine test.
  • Benign Adrenal Tumour that secretes too much Aldosterone hormone.  The blood is tested for aldosterone and renin levels. The blood test results are influenced by anti blood pressure medication & it may be recommended you change to different (temporary) medication for a short time having the blood test. An Aldosterone to Renin ratio of greater than 20 is considered abnormal.
  • Phaeochromocytoma – a tumour that secretes adrenaline. Tested for on a blood test for “metanephrines.”

Medication can sometimes up the blood pressure. A high dose of oestrogen in the contraceptive pill may put up the blood pressure which is one of the reasons why women on the pill should get their blood pressure checked. Other prescribed medication includes cyclosporine and erythropoetin. Over-the-counter Pseudoephedrine tablets have been implicated in causing the blood pressure to rise.

What can I do to get the Blood Pressure down?

  • Weight loss: 10Kg weight loss will bring BP down by around 6 – 10 mm which is around the same as one Blood Pressure lowering medication
  • Exercise
  • Reduce Alcohol – a heavy alcohol intake has a very significant effect on the Blood Pressure.
  • Reduce dietary Salt – most people have enough salt in their diet, few people need to add it in (There’s salt in breakfast cereals, bread and other foods)

The DASH diet was a well performed randomised trial published in the New England Journal of Medicine as long ago as 1997. The study of 459 adults with mildly raised blood pressure involved an 8 week DASH diet “diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated and total fat.” There http://www.nejm.org/doi/full/10.1056/NEJM199704173361601was no different in weight between the normal diet and the DASH diet yet the blood pressure went down by an average of 5.5/3 in the DASH diet group.

10Kg weight loss will bring BP down by around 6 – 10 mm which is around the same as one Blood Pressure lowering medication

When does High Blood Pressure need treating?

Blood Pressure is a vascular risk along with other risk factors. Therefore, the Blood Pressure may be acceptable when it’s a little higher in someone without have significant vascular risk factors.

Blood Pressure lowering medication is recommended:

  • For stage 2 Hypertension, or
  • For Stage 1 Hypertension when there are:
  1. Vascular Risk Factors (Diabetes, Renal disease, Cardiovascular disease, High Cardiovascular risk Calculation which involves using a risk calculator once the lipid results are known),
  2. or any signs of damage to an organ from Hypertension (ECG/eyes/kidneys)

The logic behind this is that a person with a high overall cardiovascular risk will benefit more from a lower blood pressure than a person who only has high blood pressure.

What should the target blood pressure be?

There is increasing evidence that a blood pressure lower than the traditional cut-off can be beneficial.

The SPRINT trial was published in 2015. This study found a small benefit for treating Blood pressure at the higher end of the “normal range”. The average systolic Blood pressure measured by an automated machine was just 137 at the start of the trial. The participants in the trial were aged over 50 years. They also had an increased risk of cardiovascular disease but excluded people with diabetes.

Those who received treatment had a systolic blood pressure of 121 at the end of the trial. The follow-up period was just over 3 years. Those in the treatment group had a small survival and cardiovascular health advantage. However, those in the treatment group also had a higher rate of adverse events.

Newer evidence has fed into the Australian 2016 hypertension guideline.

I’m worried my blood pressure is not under control.

A few words about the psychology of living with high blood pressure. Medical labels can cause distress. It’s well documented that people feel sicker after a diagnosis of “hypertension.” Try not to get worked-up about it. A person with high cholesterol would not think of themselves as “suffering from hypercholesterolaemia.” Likewise, don’t think of yourself as “suffering hypertension.” Even words like “target” may imply a battle between good and bad Blood Pressure. Perhaps doctors should talk about “goals” or “ideal blood pressure.”

A criticism of the lower-is-best approach is that people can end up feeling more like a ‘patient with hypertension’

Its not the end of the world to have high blood pressure. The issue of course is “how high?”

The benefits of treatment of mildly elevated blood pressure are really quite low. On the other hand, Equally important is to avoid a “head in the sand” approach! A sense of balance is required.

Target BP varies from person to person and will depend not only on evidence and guidelines, but importantly your attitude towards risk and medication. It is therefore important to discuss your  “personal Blood Pressure target” with your GP.

What Medication is used to treat High Blood Pressure?

There are four main classes of anti-hypertension medication:

  • ACE Inhibitor, or Angiotensin 2 receptor blocker. The respective generic names end in “peril” or “sartan.” Both are very often prescribed first line.
  • Beta blocker. The generic names end in “lol”
  • Calcium Antagonist: The generic names end in “pine.” Very often prescribed first line.
  • Diuretic  eg. Indapamide, often prescribed after ACE & Calcium antagonist. Spironolactone is another diuretic that’s been around a long time. A recent study showed this can be very effective for resistant hypertension.¹

There are others anti BP medications such as The ‘Alpha blocker.’

Each class of medication has a specific role and different side effect profiles.

Each BP medication is pushed up to the maximally effective dose. The drop of BP will be around 7-10mm per tablet. A combination of tablets is therefore often required.

One point to note is that there are some combination tablets that combine two different classes of medication such as the ACE with a Calcium Antagonist, or an ACE with a diuretic. So starting on one brand may be a strategy to allow easy switching to a different (combation) tablet in future – still taking one tablet but really it’s two!

So which medication is best? Ah, there’s no simple answer to that. Beta blockers are usually not the first treatment choice. Other than that, the consensus in Australia is that all first-line medications are similarly effective.

References

1: Spironolactone for resistant hypertension; Pathway-2 study 2015

WRITTEN BY: Dr Richard Beatty
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