Blood pressure/frequently asked questions

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HYPERTENSION

Hypertension, but more often referred to as high blood pressure, is a com­mon problem in modern day society. Up to a third of adults are affected. It tends to reflect our busy and stressful lifestyles to some degree. It is a very important risk factor for heart attack, stroke, and heart failure, as well as a common trigger for disturbances of the heart rhythm.

The term is used to characterise an elevation of the pressure of the blood circulation within the arteries. The reason that high blood pressure is important is that it puts extra stress and strain on the arteries especially in our brain, kidneys, and heart. It also increases the work that the heart has to do to pump the blood into the arteries

The top number or the systolic blood pressure broadly reflects the maxi­mum pressure that the heart has to generate when it pumps. A higher number means a higher pressure, and a lower number means a lower pressure. If the pressure drops too low then not enough blood gets to the head and kidneys and other organs, and other problems can follow.

The bottom reading or diastolic blood pressure generally reflects the pressure that the arterial pressure reaches in between heartbeats, ie. when the heart is relaxing and filling with blood waiting for the next heartbeat. We know that this number is also important to monitor in order to prevent complications with the brain, heart, and kidneys as well. Even brief rises in the blood pressure can lead to severe effects on the heart, brain, and organs, so it is important to keep your blood pressure stable.

The effect of your genes, ie. the family history, is very important in deter­mining whether you are at risk for high blood pressure.

If you have a strong family history of high blood pressure, you have to be especially careful to have your blood pressure monitored regularly. It is also important to have a healthy lifestyle to reduce the chances of developing high blood pressure. In particular keeping a healthy weight, taking regular exercise, avoiding excess alcohol/salt/and caffeine are im­portant things to do to avoid high blood pressure. Eating plenty of fruit and vegetables is another good way to reduce your chances of developing high blood pressure.

What is blood pressure?

Blood pressure is the pressure inside the blood vessels that occurs as a result of blood being pumped around the body by the heart. It varies continuously throughout the day.

How is blood pressure measured?

Your blood pressure is checked by using a measuring device called a sphygmomanometer (pronounced sfig-mo-manom-eter). A special cuff is fitted around an upper arm and inflated to measure your blood pressure. This will be checked periodically by your doctor or health professional, and the readings obtained by slowly deflating the cuff and watching the sphygmomanometer are the systolic blood pressure (when the heart pumps), and the diastolic blood pressure (when the heart relaxes).

Having a BP reading is a quick, simple and painless test.

What types of sphygmomanometer are used?

There are two types of this measuring instrument, manometric and digital.

The manometric devices are operated manually, are used in con­junction with a stethoscope, and are connected to an instrument that records the blood pressure, using either a calibrated vertical apparatus to display the height of a column of mercury, or displays the pressure on an aneroid gauge.

The other type of sphygmomanometer is a digital device that is operated electrically and the blood pressure is provided as a digital readout on a small screen. A stethoscope is not required for the digital device.

Although the digital units are able to be purchased privately to en­able home monitoring of blood pressure, the traditional manometer devices remain the most accurate method of measuring and moni­toring blood pressure.

How often should I have my home blood pressure monitor checked?

Non-mercury sphygmomanometers should be calibrated or checked every 6 months

How common is hypertension?

Hypertension is very common in Australia, and indeed worldwide. In the Australian National Heart Survey 2004-2005 the incidence of hypertension was approximately 40% of the population over 65 years of age.

Why is hypertension important?

Hypertension causes strokes, heart attacks, and chronic kidney dis­ease. It is the number #1 treatable risk factor for stroke. It is also a treatable cause for atrial fibrillation and heart failure. Over time, high blood pressure can damage the arteries supplying blood to the various organs including the heart, head, and kidneys. It can also damage the heart muscle due to overwork. Both the systolic (higher reading) and diastolic (lower reading) have been proven to be important targets to control to prevent cardiovascular complica­tions such as stroke and heart attack.

Are there any symptoms with hypertension?

Generally, hypertension causes no symptoms, and as such is often referred to as the “silent killer”. Some people are aware of head­ache, dizziness, blurred vision, or palpitations, all of which can be a sign of impending complications from high blood pressure.

What causes hypertension?

Over 90% of causes of hypertension are classified as essential, or idiopathic hypertension. This means that there is no identified un­derlying treatable factor as a cause for the hypertension.

As you get older the chances of developing high blood pressure increase. A family history of high blood pressure and an unhealthy lifestyle are major factors contributing to high blood pressure. Cer­tain medications can cause high blood pressure, in particular corti­costeroids and non-steroidal anti-inflammatory drugs.

In 5% – 10% of patients, there are readily identifiable causes of hypertension. This would include narrowing of the arteries that supply the kidneys ,or ‘renal artery stenosis’, that can be detected by either ultrasound or CT scanning and can be treated with balloon dilatation or managed with medication.

Other causes of hypertension that are rare, but nonetheless need to be ruled out in those patients with severe hypertension, include Cushing’s disease. This can be diagnosed either by blood tests or 24 hour collection of urine and can be treated either with medica­tion, or sometimes with surgery.

There are other rarer endocrine or glandular causes of high blood pressure, some of which can be treated with specific medications

What is a normal blood pressure?

Normal blood pressure is less than 120/80 mm Hg. A blood pressure in the range of 120-139 systolic and 80-89 diastolic is classified as high normal blood pressure. Grade 1, or mild hy­pertension, is diagnosed where the range falls between 140-159 systolic and 90-99 diastolic. A Grade 2, or moderate hyperten­sion, is diagnosed where the reading is between 160-179 sys­tolic and 100-109 diastolic. A blood pressure of greater than 180/110 is classified as Grade 3, or severe hypertension.

I have heart disease, so what blood pressure should I have?

The Australian guidelines recommend a blood pressure of less than 130/80 for patients with heart disease or stroke/transient ischaemic attack (TIA).

What does my doctor mean by saying I have white coat hyper­tension?

Some patients have a high blood pressure when they see their doc­tor, but have a normal blood pressure when they are away from the clinic. It is thought that this type of blood pressure is related to the stress of the clinic visit. To check the presence of the white coat syndrome, your doctor may organise a 24 hour blood pres­sure monitor to check your blood pressure during a period of time outside the clinic. Alternatively, a series of readings may be made outside the clinic using a home blood pressure kit. If the readings outside the clinic are normal then the diagnosis of white coat hy­pertension may be made.

“Blood pressure in each arm can differ”

Based on recent data from the UK there has been another push for doc­tors to measure blood pressures in both arms as part of their initial as­sessment.

A difference of 10 mm Hg between arms should raise suspicion of vascu­lar narrowing in the blood vessel, while a difference of 15 mm Hg raises even more suspicion.

While these links raise suspicion for narrowing in the blood vessel to the arm, they may also give rise to suspicion in arteries elsewhere in the body, and may indicate an increased risk of stroke, cardiovascular dis­ease, and peripheral vascular disease.

What medications that I may be taking could produce high blood pressure?

Common medications that can produce high blood pressure include corticosteroids, non-steroidal anti-inflammatory drugs, certain an­ti-depressants, and the oral contraceptive pill.

What complimentary medicines can cause high blood pres­sure?

Common ones include those containing caffeine, eg. guarana, mel­atonin and St John’s wart. What is the upper acceptable waist and weight measure for hypertension management? A body mass index below 25, and a waist measurement below 94 cm in males and 80 cm in females, is recommended.

What tests might the doctor order when high blood pressure is detected?

Some blood tests looking at kidney function, sodium and potas­sium salt levels, blood sugar and cholesterol may be taken. You may also have a urine check and an electrocardiogram (ECG) of your heart’s electrical activity. Other tests may be requested if an underlying problem is suspected.

What lifestyle measures are required?

At least 30 minutes of moderate exercise on most, if not all, days of the week is recommended. Dietary salt restriction to less than 4 grams a day and ideally less than 2 grams per day, is recommended. Alcohol should be restricted to no more than 2 standard drinks a day for men and no more than 1 standard drink a day for womenif on blood pressure tablets or where there is high blood pressure. Smoking should be stopped. Avoiding caffeine may help.

Maintaining a healthy weight will assist in obtaining a healthy blood pressure. Aim for a body mass index of 20-25. Pursue a waist measurement below 94 cm for males, and below 80 cm for females. Reducing stress by including adequate leisure time and relaxation may be beneficial as well. Meditation, deep breathing, or yoga can help control stress.

“Drinking black tea can reduce blood pressure”

A recent study of 95 patients from Western Australia suggested that drinking three cups a day of black tea can reduce blood pressure by 2-3 mm in both systolic and diastolic blood pressure.

Black tea is a common source of flavonoids that have been suggested to contribute to vascular health. They can help nitric oxide and reduce plasma concentrations of endothelin 1, contributing to reductions in vascular tone and blood pressure.

What blood pressure fall can be expected with non-drug mea­sures?

Regular physical exercise of 30 minutes a day can produce an aver­age fall of 4/2.5 mm Hg, while 1% of weight loss will produce an average fall in systolic blood pressure of 1%.

“Even modest exercise helps reduce blood pressure”

A recent study from New York showed that even modest amounts of ex­ercise could help reduce blood pressure. Over a 6 month period, a group of 404 overweight, obese, or sedentary females aged 45-75 years were assigned to three groups with varying levels of exercise.

The group assigned to the lowest intensity of exercise (half of the rec­ommended two and a half hours a week of moderate activity exercise) achieved an average 11mm drop in systolic blood pressure, while those in the most active group (four hours a week) recorded the most benefit at an average drop in systolic blood pressure of 14 mm Hg.

The researchers concluded that even“simple things like a walk around the neighbourhood”can be enough…“you don’t have to go to the gym”

 

What dietary regimes can help lower blood pressure?

The DASH (Dietary Approaches to Stop Hypertension) diet is a well-studied diet to lower blood pressure. It produces modest anti­hypertensive effects in both people with hypertension (an average reduction of 11/6 mm Hg) and those with normal blood pressure (an average reduction of 6/3 mm Hg).

The diet menu is an adaptable and balanced eating plan and is en­dorsed by the National Heart Lung and Blood Institute, the Ameri­can Heart Association, and the US guidelines for treatment of Hypertension. The DASH diet is available online at: http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf

A Few Features Of The Dash Diet Menu

Food Group Daily Servings
Fruits/Vegetables 4-5
Low-fat dairy products 2-3
Grains 6-8
Lean meats/poultry/fish 6 or less
Fat/oils 2-3
Nuts, seeds and legumes 4 -5
Sweets and added sugars 5 or less
Alcoholic beverages avoid or moderate

 

What is the role of stress in producing high blood pressure?

Stress is an important factor in high blood pressure. Some people are very prone to getting high blood pressure as a result of stress­ful events, both emotionally and physically, such as the death of a loved one or possibly some physical problem such as an operation, or even an infection. Everybody varies in their response to these stresses, although some of us are more prone to elevation of blood pressure than others.

Your doctor may monitor the situation if it is thought that a tem­porary transient rise in blood pressure is related to a physical or stressful condition and that condition is likely to disappear sponta­neously over the coming weeks.

How do doctors decide on the best hypertension treatments?

To best decide on hypertension treatment your doctor will look at a number of factors including your overall cardiovascular risk, life­style factors, previous treatments, best-practice evidence, and dis­cuss the best treatment options with you.

How do the various blood pressure drugs actually work?

Calcium channel blocker drugs relax the blood vessels and the heart. They are generally well tolerated and are the first medica­tion recommended in many cases.

Diuretic drugs work by removing excess salt and water from the body in order to lower the blood pressure. They are not suitable for everyone. Those with diabetes need to be careful as these medica­tions may cause an elevation in blood sugar, in particular the thia­zide diuretics.

ACE inhibitor medications or angiotensin-converting-enzyme in­hibitors help to reduce the activation of an enzyme called angioten­sin that constricts blood vessels. Another class of drugs called an­giotensin 2 receptor blockers act to block the effects of angiotensin on blood vessel constriction.

Beta blocker drugs reduce the action of adrenaline on the heart. They reduce the force of contraction of the heart thereby lessening the blood pressure.

What about fixed dose combinations?

Fixed dose combinations of 2 or even 3 antihypertensive agents are becoming more frequently used in modern hypertension manage­ment. They consist of 2 or 3 active drug agents in a fixed dose tab­let, giving the benefits of 2 different drugs in a single tablet. They have the advantages of being cheaper than the two separate drugs, and patients are more likely to take them as a single pill.

Why do I need more than 1 drug to control my blood pressure?

Most of the large blood pressure trials have shown that an average of 2 to 3 drugs are often required to achieve acceptable blood pres­sure control. Strictly following the correct lifestyle measures will reduce the chances of needing multiple drugs to control your blood pressure.

What Are Common Side-Effects To Typical Antihypertensive Drugs?

SIDE-EFFECT MEDICATION
Constipation Calcium channel blockers (especially Verapamil)
Cough ACE inhibitors (eg. Perindopril and Ramipril)
Dyspnoea (short of breath) Beta blockers (eg. Atenolol and Metoprolol)
Erectile dysfunction Thiazides and Beta blockers
Fluid swelling Calcium channel blockers
High blood potas­sium ACE inhibitor and angiotensin receptor blockers (eg. Irbesartan)
High blood sugar Thiazides
Postural hypotension (low blood pressure on standing up) All except beta blockers

Are there any non-drug treatments on the horizon for resistant high blood pressure?

In some cases, the blood pressure may be resistant to multiple drugs. Un­derlying causes, for example a gland problem, or kidney problem such as arterial narrowing, will be some of the things that your doctor will likely exclude.

For treatment-resistant hypertension, an innovative new procedure con­sisting of applying radiofrequency ablation to the kidney arteries is be­ing tested. This new procedure is minimally invasive and is called renal denervation or RDN.

Catheter-based renal denervation to ablate renal sympathetic nerves uses the Symplicity catheter system and involves a technique performed under local anaesthetic to the groin artery. A small plastic tube or catheter is placed into the artery and advanced to the arteries supplying the kidneys, and then a controlled series of radio waves is directed to those arteries to disable certain nerve fibres that are responsible for maintaining high blood pressure

The results of an initial study published in the Lancet in 2010 (Sym­plicity HTN-2 trial) described a 33/11 mm Hg drop in blood pressure at 6 months post-treatment. Moreover, at the latest American College of Cardiology meeting held in Chicago in 2012, the following results were presented to highlight the most recent positive developments with the RDN procedure, namely:

after 3 years, renal artery radiofrequency ablations with the Sym­plicity catheter system are showing a persistent reduction in sys­tolic blood pressure by over 30 mm Hg;

the RDN procedure appears well tolerated without any undesirable major side-effects;

there was no loss of kidney function overall in the 153 patients studied in Australia, the United States, and Europe, and the benefits appear sustained after 3 years of follow-up;

to date, approximately 4,000 patients have been treated worldwide with the RDN procedure; and

further trials are under way for this promising technique

Resistant Hypertension

For 20 years, Anne who is a 60 year old lady, had been having high blood pressure with systolic blood pressure regularly sailing over 200 mm Hg.

“…nothing extra was done about it because they didn’t know that any­thing could be done about it…”

After a visit to a cardiologist who suspected an underlying problem, Anne had a series of blood tests and scans. It was found that she had a slow growing tumour on her adrenal gland that was producing very high lev­els of the hormone Aldosterone. After a visit to another specialist it was decided that laparoscopic surgery could help Anne. She had the surgery and it has “changed her life”.

“I am very happy that I had the surgery done…my blood pressure still needs medication but I don’t see the high numbers I used to see…”

She still takes medication but her blood pressure is generally well con­trolled with blood pressures averaging around the 130 mm Hg systolic.

Patients with resistant hypertension are those that are more likely to have some underlying cause driving the blood pressure up and not responding to lifestyle measures and drugs, according to Dr Alistair Begg.

“These are those types of patients that need specialist review, and pos­sibly further tests to look for a correctable cause for their blood pressure. About 5-10% of people with hypertension will have what is termed sec­ondary hypertension, that is, with an underlying cause, while the other 90-95% will have a primary, or essential hypertension. Drug resistance is one clue to an underlying correctable cause, and should raise suspicions of an underlying cause”

Is there a cure for blood pressure problems?

Certainly weight loss, exercise and maintaining a healthy diet will cure a number of patients with high blood pressure. However, there are many who do not respond to conservative therapies. Your doctor may do a screening set of blood tests looking for evidence of any treatable causes such as kidney disease or possibly glandular problems. In 5% to 10% of cases, there are potentially curative causes for high blood pressure.

Is high blood pressure due to blocked arteries?

High blood pressure can be due to blockages in the arteries that supply the kidneys. If the kidneys are starved of blood flow, there are receptors in the kidneys that tell the body to retain salt and water, thereby producing high blood pressure. Your doctor will know about these problems and, based on your risk factors and the tests that are performed, may order some further tests on the kid­neys such as a renal ultrasound or a CT scan to look for underlying blockages in your kidney arteries.

What about sleep disorders such as sleep apnoea?

Sleep-disordered breathing affects up to 1 in 5 people in the com­munity. It often co-exists with high blood pressure. The risk fac­tors for sleep-disordered breathing, such as being overweight and excess alcohol consumption, can also produce an elevation of blood pressure. However, the effects of sleep apnoea, which include a lack of oxygen to the brain and a disturbance of the sleep, can also lead to an elevation of blood pressure directly. Certainly, treatment of significant sleep apnoea can lead to a dramatic improvement in control of blood pressure.

One factor that may warn your doctor to the possibility of sleep apnoea causing high blood pressure is a blood pressure that seems to be particularly elevated in the morning hours. Your doctor will be alert to this possibility and it is certainly one of the factors that are looked at by specialists in considering those patients that do not respond adequately to high blood pressure tablets.

What about lifestyle in blood pressure control?

Certainly, there are patients who have significantly stressful life­styles and, for many, this contributes to poorly controlled blood pressure. There is good evidence that leading a more relaxed pace with perhaps some medication, a daily walk, getting plenty of fresh air, having a healthy diet with lots of fresh fruit and vegetables, and avoiding processed foods, can lead to an improvement in blood pressure.

What is a transient ischemic attack or TIA?

A transient ischemic attack, or TIA, is a reversible loss of function of part of the brain caused by a lack of blood flow to a particular part of the brain. TIA is also known as a mini-stroke. The fact that the brain recovers within a 24 hour time period makes the classifi­cation a TIA, whereas a stroke is a permanent deficit. Hence, a TIA by definition is transient and reversible.

There are many causes for TIA, but high blood pressure is the num­ber #1 cause. Therefore, it is essential that blood pressure is well controlled both to prevent the onset of a TIA, and also in order to try and prevent a stroke in those patients who already suffer from TIAs.

What is a stroke?

A stroke is a permanent loss of function to a part of the brain due to a lack of blood flow. This could be caused by a blockage in the artery in the brain, a blockage in an artery in the neck, or even as a result of a serious haemorrhage. But, in 10% – 15 % of cases, a stroke can also be due to a blood clot that arises from the heart. The most common reason for a blood clot arising from the heart would be due to atrial fibrillation. This is a particularly common problem in western communities.

Why do we treat high blood pressure?

Treatment of high blood pressure is important to prevent compli­cations, in particular the development of stroke as this is the most catastrophic complication of high blood pressure. Nevertheless, it is likewise important to prevent heart failure and heart attack, just as high blood pressure treatments play a significant role in the pre­vention of kidney disease, principally kidney failure.

What are the 10 steps to manage high blood pressure?

1. Know your blood pressure and have it checked regularly.

2. Eat a healthy diet, high in fruit and vegetables, avoiding excess salt and fat. Become an expert in reading food labels.

3. Avoid excess alcohol and caffeine.

4. Maintain a healthy weight.

5. Be active. Walk 30 minutes a day.

6. Follow your doctor’s advice, and know about your medication.

7. Don’t run out of medicines or forget to take them.

8. Look after those around you. Make sure your family and friends get their blood pressure checked too.

9. Stop smoking.

10. Relax and have a happy life. Meditation may help as may getting a pet such as a dog.

Dr Alistair Begg is a Cardiologist with 15 years experience in private practice.He is actively involved in Cardiac Rehabilitation and patient education including a number of forums such as the DVD ‘What’s wrong with my heart’ ,books,and smartphone applications.For more about these publications visit http://www.whatswrongwithmyheart.com

Married with 2 children - I have been in private practice cardiology for 15 years. Dr Alistair Begg MBBS FRACP FCSANZ DDU is an experienced cardiologist with special interests in echocardiography, stress echocardiography, coronary intervention and general cardiology. He has particular expertise in stress echocardiography. Dr Begg joined SA Heart in 2007. Alistair has had 15 years of private practice experience in Sydney and Adelaide, and has previously worked as a cardiologist at Flinders Medical Centre. He graduated in medicine from the University of Adelaide in 1989 and commenced his post graduate training in cardiology at Flinders Medical Centre before completing his post-fellowship training in Sydney. He was awarded his Fellowship to the Royal Australasian College of Physicians (FRACP) in 1996. Dr Begg went on to obtain his Diploma of Diagnostic Ultrasound (DDU) in 1997 and in 2006 was awarded his Fellowship of the Cardiac Society of Australia and New Zealand (FCSANZ). In 2008 he completed level 2 training for CT coronary angiography and this complements his special interest in cardiac Imaging. Dr Begg consults regularly at Ashford. He has a particular interest in patients with chest pain, heart failure or patients with significant risk factors. He is actively involved in cardiac rehabilitation. He lectures to patient groups,general practitioners,and has previously taught medical students both in Adelaide and Sydney.He currently mentors Cardiology trainees on rotation from the Queen Elizabeth Hospital. He has published articles in international medical journals and recently has published a cardiac education DVD for patients titled 'what's wrong with my heart'. He also has been involved as a co-investigator in a number of international clinical trials,and currently is involved in two clinical trials involving coronary artery disease and heart failure. He was a director and board member at SA Heart from 2007 until 2012.

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