Download Week 23 Learning Objectives Clinical Assessment of the

Week 23 Learning Objectives
Clinical Assessment of the Cardiovascular System in Hypertension (Part 2)
4. Recognise and understand the clinical features of hypertension and their underlying mechanisms.
Hypertension is one of the most difficult conditions to diagnose simply because most of the time it is
completely asymptomatic. In many cases, a patient will only discover that they have hypertension from
a visit to the doctor for a different purpose. The condition of hypertension could have many causes as a
result hypertension is split into two groups:
Essential – If the cause is unknown
Secondary – If the cause is the result of another known condition
Hypertension itself is the direct result of either an increased cardiac output or an increase in peripheral
resistance (or both). All clinical features of hypertension therefore will result from one or both of these
mechanisms.
Cardiac output:
Increases of cardiac output will directly increase arterial (blood) pressure. Keeping in mind that:
 Cardiac Output = Stroke Volume x Stroke Frequency
Hypertension could present itself with tachycardia (increased heart rate) as well as palpitations from a
heart trying to contract very hard to increase stroke volume. In addition, long term over-use of cardiac
muscle can result in the growth of that muscle. Hence, left ventricular hypertrophy is one very common
clinical manifestation of long-term hypertension.
Cardiac output is directly influenced by:

The autonomic nervous system may influence heart rate when the sympathetic nervous system
stimulates cardiac muscle contractions or when the parasympathetic system inhibits cardiac
muscle contractions.

Chemicals such as hormones and ions can influence heart rate. Epinephrine, secreted by the
adrenal medulla, and thyroxin, secreted by the thyroid gland, increase heart rate. Abnormal
blood concentrations of Na+, K+, and Ca2+ interfere with muscle contraction.
Peripheral Resistance:
An increase in the peripheral resistance of the blood vessels will cause an increase in arterial blood
pressure. An increase in resistance can happen as the result of:
 A change of the vascular structure like a pathological narrowing of arteries from the
accumulation of plaque deposits
 A change in the vascular function like the normal constriction of the structure as a result of the
actions of a vasoconstrictor
These two situations, especially the latter, can happen as secondary results to a number of primary
pathologies involving the kidneys, endocrine disorders, neurological disorders and vascular disorders.
Each one of these disorders may present with their own clinical features on top of those derived from
hypertension.
When the structure of a blood vessel is interrupted, this will most likely cause an abnormal flow of blood
or even a cessation of flow through that vessel. As a result, the blood vessel may undertake extreme
amounts of pressure caused by the restriction. This could cause the development of aneurysms or
hemorrhages. Additionally, the lack of blood flow to parts of the body can result in infarcts and the
necrosis of tissues. Clinically, any of these can result in pain or bleeding. Vessels can also swell with the
added pressure of the blood and press against surrounding structures. Though relatively uncommon,
this can present as a chronic headache due to added pressure within a compartment (skull) with some
cases of hypertension. In more severe cases, loss of vision and consciousness can occur.
Summary:
While hypertension asymptomatic more often than not, it can present with numerous clinical features.
These can include:
 Pain – can occur in many places as the result of extra pressure on blood vessels and surrounding
structures
 LV Hypertrophy – the result of a long term increase in stroke volume and cardiac output
 Increased Blood Pressure – the result of an increased cardiac output and/or and increase in
peripheral resistance
 Increased Urination – increase in arterial pressure will increase GFR and subsequent urine
output
 Ischemic Disease – abnormal blood flow can result in the lack of perfusion to tissues
All clinical features of hypertension (not including any other compounding features from causative
disorders), come from the effect of increasing the pressure in the blood vessels.
5. Outline the investigations involved in the assessment of blood pressure status.
Blood pressure status is assessed by measuring blood pressure!
There are a number of ways to measure blood pressure but they can all be divided into two main
groups:


Invasive – a method that involves entering the body
Non Invasive – a method that does not involve entering the body
Invasive methods are the most accurate way of measuring blood pressure but are typically restricted to
clinics and hospitals with adequate equipment because of the risk of infection, bleeding or other
complications. The most common method is the measurement of the blood pressure through an arterial
line. A cannulae is inserted into a major artery (usually radial, femoral, or brachial) with an electronic
pressure sensor. This sensor will detect the blood pressure directly in the vessel making it the most
accurate method of measuring. Additionally, the sensor is connected to a computer system which is able
to keep track of the blood pressure and changes to blood pressure constantly.
Non invasive methods are the most convenient way of measuring blood pressure. There are a number of
ways of measuring blood pressure non invasively:
 Palpation
 Auscultation with Sphygnomamometer
 Oscilliometric Measurement
Palpation of an artery can give a very rough measurement of blood pressure but is very quick to do.
According to the BMJ: The advanced trauma life support course teaches that if only the patient's carotid
pulse is palpable, the systolic blood pressure is 60-70 mm Hg; if carotid and femoral pulses are palpable,
the systolic blood pressure is 70-80 mm Hg; and if the radial pulse is also palpable, the systolic blood
pressure is more than 80 mm Hg.
Auscultation with a sphygnomamometer is the most effective way of measuring the blood pressure noninvasively. It involves palpating and auscultating the systolic and diastolic blood pressures with the
assistance of a sphygnomamometer and an aneroid gauge (preferably a mercury manometer).
The auscultation procedure is as follows:
This requires, at the very least, an inflatable cuff with a pressure gauge (sphygmomanometer). Wind the
cuff round the arm (which should be at about heart level) and inflate it to a pressure higher than the
expected blood pressure. Then deflate the cuff slowly. With a stethoscope, listen over the brachial
artery. When the cuff reaches systolic pressure, a clear tapping sound is heard in time with the heart
beat. As the cuff deflates further, the sounds become quieter, but become louder again before
disappearing altogether. The point at which the sounds disappear is the diastolic pressure. If you have
no stethoscope, the systolic blood pressure can be found by palpating the brachial artery and noting the
pressure in the cuff at which it returns.
The sounds heard while measuring blood pressure in this way are called the Korotkoff sounds, and
undergo 5 phases:
1.
2.
3.
4.
5.
initial 'tapping' sound (cuff pressure = systolic pressure)
sounds increase in intensity
sounds at maximum intensity
sounds become muffled
sounds disappear
Most inaccuracies result from the use of the wrong size of cuff. A narrow cuff wrapped round a fat arm
will give an abnormally high reading, and vice versa. The World Health Organisation recommends a
14cm cuff for use in adults. Smaller cuffs for infants and children are available. In occasional patients,
the reading obtained from one arm can be different from that obtained from the other arm. An
appropriate size of cuff can be applied to the calf, and pressure estimated by palpation of the posterior
tibial pulse.
Oscilliometric measurement is done using an automated blood pressure machine. The procedure
follows the basic principle of auscultation with a sphygnomemometer but uses an automated machine
which has a pump and pressure sensor instead of requiring a person to manually auscultate and
measure.
Once the blood pressure has been measured, it can then be categorized into different stages. Note:
“Prehypertension” is also known as “High-Normal”.
Classification of blood pressure for adults age 18 years and older
Category
Systolic (mm Hg)
Normal*
less than 120
and
less than 80
120–139
or
80–89
Stage 1
140–159
or
90–99
Stage 2
160 or higher
or
100 or higher
Prehypertension
Diastolic (mm Hg)
Hypertension
6. Outline the scope of measures in management of hypertension, including lifestyle and diet, the
range of pharmacodynamic actions which are employed for treatment, and the influence of effective
management on survival and complications.
Hypertension is managed by two ways:
 Pharmacologically
 Changes to Lifestyle
The mainstay of treatment of hypertension is pharmacological intervention. Drugs can work directly to
reduce blood pressure by
 Reducing the overall volume of fluids in the body
 Acting to relax the muscle tone of the arteries
 Acting directly on the heart to reduce cardiac output
 A combination of any of the actions above
The following are classes of drugs used for hypertension:
Diuretics
Diuretics help the kidneys get rid of excess salt and water thus reducing the overall fluid levels in the
body. A reduction of the overall fluid levels will reduce the volume of plasma, thus reducing the pressure
in the vessels. They are also especially helpful for treating patients with heart failure, patients with
isolated systolic hypertension, the elderly, and African-Americans. (African-Americans are more likely to
be salt-sensitive, so they respond well to these drugs.) They also work well for patients with diabetes.
Results of a major long-term study have suggested that diuretics work just as well as newer drugs in
lowering blood pressure and are more effective in preventing heart failure, heart attack, and stroke. In
the study, the benefits of the diuretic were even more significant for African-American patients. Other
trial results indicated that patients taking a calcium channel blocker had the greatest risk for heart
failure, and that an ACE inhibitor was much less effective than the diuretic in lowering blood pressure
and preventing stroke in African-American patients.
Diuretic Types and Brands. The many brands of diuretics are generally inexpensive. Some need to be
taken once a day, some twice a day. Low doses are usually as effective for lowering blood pressure as
higher doses. Diuretics are usually used in combination with other drugs, especially ACE inhibitors and
beta blockers.
The three main types of diuretics include:


Thiazide diuretics. These include chlorothiazide (Diuril), chlorthalidone (Hygroton), indapamide
(Lozol), hydrochlorothiazide (Esidrix, HydroDiuril), bendroflumethiazide (Naturen),
methylclothiazide, (Edduran), and metolazone (Mykrox, Zaroxolyn). In most cases, thiazides are
preferred to other diruetics for treatment of high blood pressure.
Potassium-sparing diuretics. These include amiloride (Midamor), spironolactone (Aldactone),
and triamterene (Dyrenium).

Loop diuretics. Because loop diuretics act faster than other diuretics it is important to avoid
dehydration and potassium loss. Loop diuretics include bumetanide (Bumex), furosemide (Lasix),
ethacrynic acid (Edecrin), and torsemide (Demadex).
Problems with Diuretics.

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Loop and thiazide diuretics reduce the body's supply of potassium, which, if left untreated,
increases the risk for arrhythmias. Arrhythmias are heart rhythm disturbances that can, rarely,
lead to cardiac arrest. In these cases, doctors will prescribe lower doses of the current diuretic,
recommend potassium supplements, or use potassium-sparing diuretics either alone or in
combination with a thiazide.
Potassium-sparing drugs have their own risks, which include dangerously high levels of
potassium in people with existing elevated levels of potassium or in those with damaged
kidneys. However, all diuretics are generally more beneficial than harmful.
Thiazide diuretics may increase blood sugar levels.
Erectile dysfunction (impotence) may be a side effect of thiazides.
Elevated uric acid levels, and possibly gout, may be caused by thiazide diuretics.
Common Diuretic Side Effect Symptoms.
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Fatigue
Depression and irritability
Urinary incontinence
Reduced sexual drive and problems with obtaining and maintaining an erection
Beta-Blockers
Beta-blockers help slow heart rate and lower blood pressure. They are usually used in combination with
other drugs such as ACE inhibitors and diuretics. Beta-blockers are more likely to be used to treat
hypertension in patients with angina, previous heart attack, heart failure, arrhythmias with fast heart
rates, or migraine headaches.
Brands. Propranolol Propranolol (Inderal), acebutolol (Sectral), atenolol (Tenormin), betaxolol (Kerlone),
carteolol (Cartrol), metoprolol (Lopressor), nadolol (Corgard), penbutolol (Levatol), pindolol (Visken),
carvedilol (Coreg), timolol (Blocadren), and nebivolol (Bystolic). The drugs may differ in their effects and
benefits.
Problems with Beta-Blockers.

Do not abruptly stop taking these drugs. The sudden withdrawal of beta-blockers can rapidly
increase heart rate and blood pressure and potentially cause angina or heart attack. If you need
to stop your beta-blocker, the doctor may want you to slowly decrease the dose before stopping
completely.



Beta-blockers are categorized as non-selective or selective. Non-selective beta blockers, such as
carvedilol and propranolol, may sometimes narrow bronchial airways. Patients with asthma,
emphysema, or chronic bronchitis should not use these medicines.
Beta-blockers may lower HDL (“good”) cholesterol.
These drugs can hide warning signs of low blood sugar (hypoglycemia) in patients with diabetes.
When combined with a diuretic, the risk of diabetes may increase.
Common Side Effects.

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Fatigue and lethargy
Vivid dreams and nightmares
Depression
Memory loss
Dizziness and lightheadedness
Reduced ability to exercise
Coldness in extremities (legs, toes, arms, hands)
Reduced sexual drive and problems with obtaining and maintaining an erection
Check with your doctor about any side effects. Do not stop taking these drugs on your own.
ACE Inhibitors
Angiotensin-converting enzyme (ACE) inhibitors open blood vessels and decrease the workload of the
heart. They treat high blood pressure but can also help protect the heart and kidneys.
Patients with heart failure or an enlarged left ventricle, previous heart attack, diabetes, or kidney
disease are considered particularly good candidates for ACE inhibitors as part of treatment for high
blood pressure.
ACE inhibitors are particularly important for patients with diabetes and heart failure. A large study
reported that patients with diabetes who took these drugs had fewer heart attacks and lower overall
mortality rates than patients who took other types of high blood pressure medications. ACE inhibitors
may also help slow progression of kidney disease, in addition to controlling blood pressure.
Aspirin is recommended for preventing death in patients with heart disease, and can safely be used in
combinatin with ACE inhibitors, particularly at lower dosages of aspirin (75 - 81 mg).
Brands. ACE inhibitors include captopril (Capoten), enalapril (Vasotec), quinapril (Accupril), benazepril
(Lotensin), ramipril (Altace), perindopril (Aceon), and lisinopril (Prinivil, Zestril).
Common Side Effects of ACE Inhibitors.


Low blood pressure is the main side effect of ACE inhibitors. This can be severe in some patients,
especially at the start of therapy.
Irritating cough is a common side effect, which some people find intolerable. ACE inhibitors can
have this side effect, but angiotensin-receptor blockers do not.

ACE inhibitors can harm a developing fetus and should not be used during pregnancy. While it
has long been known that these drugs can cause problems in the second and third trimester, an
important 2006 study indicated that ACE inhibitors can also cause major heart birth defects
when taken during the first trimester. The Food and Drug Administration (FDA) and the
American Heart Association recommend that women who become pregnant should change
from ACE inhibitors to another type of blood pressure drug as soon as possible. Women of childbearing age who are considering becoming pregnant should also discuss other medicines with
their doctors.
Uncommon Side Effects of ACE Inhibitors.



ACE inhibitors protect against kidney disease, but they may also increase potassium retention by
the kidneys. If potassium levels become extremely high, they can cause the heart to stop
beating (cardiac arrest). This side effect is rare, except in patients with significant kidney disease.
Because of this risk, ACE inhibitors are not usually used in combination with potassium-sparing
diuretics or potassium supplements.
A rare but severe side effect is granulocytopenia, an extreme reduction in infection-fighting
white blood cells.
In very rare cases, patients suffer a sudden and severe allergic reaction, called angioedema that
causes swelling in the eyes and mouth and may close off the throat.
Patients who have difficulty tolerating ACE inhibitor side effects are usually switched to an angiotensinreceptor blocker (ARB).
Angiotensin-Receptor Blockers (ARBs)
ARBs, also known as angiotensin II receptor antagonists, are similar to ACE inhibitors in their ability to
open blood vessels and lower blood pressure. They may have fewer or less-severe side effects than ACE
inhibitors, especially coughing, and are sometimes prescribed as an alternative to ACE inhibitors. In
general they are prescribed to patients who cannot tolerate or did not respond to ACE inhibitors.
Brands. Losartan (Cozaar, Hyzaar), olmesartan (Benicar) candesartan (Atacand), telmisartan (Micardis),
eprosartan (Teveten), irbesartan (Avapro), and valsartan (Diovan). A combination medication containing
candesartan and the diuretic hydrochlorothiazide (Diovan HCT, Atacand HCT) is also available.
Side Effects.
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Low blood pressure
Dizziness and lightheadedness
Raised potassium levels
Drowsiness
Nasal congestion
Should not be used during pregnancy
Calcium-Channel Blockers (CCBs)
Calcium-channel blockers (CCBs), or calcium antagonists, help relax blood vessels. Along with diuretics,
CCBs may work better than other drug classes for lowering blood pressure in African-Americans. Recent
research indicates that newer types of drugs (CCBs, ACE inhibitors) may be a better treatment option for
some patients than older drugs (especially beta-blockers).
Brands. Diltiazem (Cardizem, Dilacor), amlodipine (Norvasc), felodipine (Plendil), isradipine (DynaCirc),
verapamil (Calan, Isoptin, Verelan), nisoldipine (Sular), nicardipine (Cardene), nifedipine (Adalat,
Procardia), lercanidipine (Zanidip), lacidipine (Motens), and nitrendipine (Nitrepin). In 2004, a dualtherapy calcium channel blocker-statin combination drug (Caduet) was approved to treat high blood
pressure and high cholesterol. Caduet is a fixed-dose combination of amlodipine and atorvastatin.
Side Effects.
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Swelling in the feet
Constipation
Fatigue
Erectile dysfunction
Gingivitis
Rash
Food interactions (do not take CCBs with grapefruit or Seville orange products)
Alpha Blockers
Alpha blockers such as doxazosin (Cardura), prazosin (Minipress), and terazosin (Hytrin) vasodlate small
blood vessels. They are generally not used as first-line drugs for high blood pressure, but are prescribed
if other drugs do not work or as add-on medication.
Vasodilators
Vasodilators help open blood vessels by relaxing muscles in the blood vessel walls. These drugs are
usually used in combination with a diuretic or a beta-blocker. They are rarely used by themselves.
Vasodilators include hydralazine (Apresoline), clonidine (Catapres), and Minoxidil (Loniten). Some of
these drugs should be used with caution or not at all in people who have angina or who have had a
heart attack.
Other Drugs
Aliskiren (Tekturna). In 2007, the FDA approved aliskiren for treatment of high blood pressure. Aliskiren
can be taken either alone or in combination with other blood pressure medication. It should not be used
during pregnancy as it can cause injury or death to the fetus. Aliskiren is the first hypertension drug that
inhibits renin, a kidney enzyme associated with the regulation of blood pressure.
Statins. Statins, common drugs used to lower cholesterol, are proving to have many other health
benefits. They include lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), fluvastatin
(Lescol), atorvastatin (Lipitor), and rosuvastatin (Crestor). In an important 2002 study, patients with high
blood pressure but normal or slightly high cholesterol levels had fewer heart attacks and strokes when
they took a statin. In 2004, a calcium channel blocker-statin combination drug (Caduet) was approved to
treat simultaneously high blood pressure and high cholesterol. Caduet is a fixed-dose combination of
amlodipine and atorvastatin.
Changes in lifestyle have been proven to have a significant impact on a hypertensive condition.
Essentially because hypertension is directly related to factors such as fluid levels, the condition of the
blood vessels and the condition of the body overall, changes to any of these conditions can affect the
hypertensive state. Lifestyle changes involve:
 Diet
 Exercise
 Alcohol
 Smoking
Obesity is clearly associated with the development of hypertension but is also related to other
mechanisms, such as insulin resistance, dyslipidemia and sympathetic nervous system upregulation
which further increases the risk of developing cardiovascular diseases. Several trials have demonstrated
that losing weight reduces both systolic and diastolic blood pressure. A 10% weight loss can reduce total
blood pressure by 7/5mmHg. In addition there is an improvement to lipid profile which will reduce the
risk of developing more obstructive plaque in the vessels. The reduction of weight is promoted with diet
and exercise.
A “better diet” consists of a cutting down of trans-fat and high density lipoprotein. This will help to
reduce the chances of developing and slow down the development of plaque in the arteries. High-fiber
diets are known to be effective in preventing and treating hypertension. The types of dietary fiber are
important - the greatest benefit to hypertension are water soluble gel-forming fibers such as oat bran,
apple pectin, psyllium seed husks and guar gum. Such dietary fiber may also reduce cholesterol levels,
promote weight loss and help remove heavy metals. Though a very strong association between a high
fiber diet and the reduction of blood pressure has been made, there has been no definitive answer for
what mechanism is the cause of this (they suspect it has something to do with the solubility of fiber
however). A hypertensive person is encouraged to reduce their dietary intake of salt. This reduction of
dietary salt will sub sequentially reduce water retention in the body, helping to lower plasma levels and
blood pressure.
Exercise is one of the most important factors to improving an individual’s blood pressure. Regular
aerobic exercise can reduce blood pressures by 8/4mmHg and reduce left ventricular mass. The effects
of exercise are actually independent of weight loss, so regardless if the patient loses weight or not, they
will still improve with exercise. Regular exercise is considered to be 45-60 minutes of moderate intensity
and performed 3 to 4 times a week. Shorter periods of exercise have less of an effect on blood pressure
even if they are more frequent.
Observational data has shown an association between alcohol intake and blood pressure although a
causal relationship has not been confirmed. Low levels of alcohol intake have been shown to provide
cardiovascular protection although heavy drinking has been associated with an increased risk for
cardiovascular problems. Abstinence from alcohol for hypertensive patients has been shown to reduce
systolic blood pressure by 5-8mmHg and diastolic pressure by 2-3mmHg.