4. Essential Hypertension
-
Upload
mimi-chukwu -
Category
Documents
-
view
223 -
download
0
Transcript of 4. Essential Hypertension
-
8/13/2019 4. Essential Hypertension
1/46
25/01/2014 1
Essential Hypertension
-
8/13/2019 4. Essential Hypertension
2/46
25/01/2014 2
Hypertension Hypertension is not a disease
It is an arbitrarily defined disorder to whichboth environmental and genetic factors
contribute
Major risk factor for:cerebrovascular disease
myocardial infarction
heart failure
peripheral vascular disease
renal failure
-
8/13/2019 4. Essential Hypertension
3/46
25/01/2014 3
This left ventricle is very thickened (slightly over 2 cm in
thickness), but the rest of the heart is not greatly enlarged.
This is typical for hypertensive heart disease. The
hypertension creates a greater pressure load on the heart to
induce the hypertrophy.
-
8/13/2019 4. Essential Hypertension
4/46
25/01/2014 4
The left ventricle is markedly thickened in this patient
with severe hypertension that was untreated for many
years. The myocardial fibers have undergone
hypertrophy.
-
8/13/2019 4. Essential Hypertension
5/46
25/01/2014 5
Blood pressure is a continuous variable
which fluctuates widely during the dayphysical stress
mental stress
The definition of hypertension has been
arbitrarily set as:
That blood pressure above which thebenefits of treatment outweigh the risks
in term of morbidity and mortality
-
8/13/2019 4. Essential Hypertension
6/46
25/01/2014 6
Blood Pressure
Exhibits a normal distribution within the
population
Increasing blood pressure is associated with
a progressive increase in the risk of stroke
and cardiovascular disease
Risk however rises exponentially and notlinearly with pressure
-
8/13/2019 4. Essential Hypertension
7/46
25/01/2014 7
At what blood pressure is a patient
hypertensive? BHS 140/90
JNC-VI 140/90 Opt
-
8/13/2019 4. Essential Hypertension
8/46
25/01/2014 8
In 95% of cases no cause can be found
In 5-10% a cause can be found
Chronic renal disease
Renal artery stenosis Endocrine disease, Cushings, Conns
Syndrome, Phaeochromocytoma, GRA
-
8/13/2019 4. Essential Hypertension
9/46
25/01/2014 9
Risks of Hypertension
The risk of hypertension is considerable
The 4thmost common cause of death world-wide
Directly and indirectly responsible for >20% of alldeaths
The risks of hypertension have been most
thoroughly determined by the Framingham Study -a longitudinal study performed in the USA
-
8/13/2019 4. Essential Hypertension
10/46
25/01/2014 10
Framingham Study
This study clearly demonstrated that therelative risk to a patient with a DBP of 99
mmHg compared to a DBP of 84 mm Hg
forStroke increases 4 fold
MI increases 2 times
The same was also found to be true forsystolic blood pressure
These pressure are common
-
8/13/2019 4. Essential Hypertension
11/46
25/01/2014 11
Despite the clear relationship between blood
pressure and morbidity the risk fromhypertension also depends on and increases
exponentially with other factors
Cigarette smoking Adds 20/10 mmHg
Diabetes mellitus 5-30 X increase MI
Renal disease
Male 2X risk
Hyperlipidaemia
Previous MI or stroke
Left ventricular hypertrophy 2X risk
-
8/13/2019 4. Essential Hypertension
12/46
25/01/2014 12
Control of blood pressure
Blood pressure is controlled by anintegrated system
Prime contributors to blood pressure are:
Cardiac output Stroke volume
Heart rate
Peripheral vascular resistance
Each of these factors can be manipulated by
drug therapy
-
8/13/2019 4. Essential Hypertension
13/46
25/01/2014 13
Sympathetic Nervous System
Sympathetic system activation produces
vasoconstriction
reflex tachycardia
increased cardiac output
In this way blood pressure is increased
The actions of the sympathetic system are
rapid and account for second to second
blood pressure control
-
8/13/2019 4. Essential Hypertension
14/46
25/01/2014 14
The renin-angiotensin-aldosterone system
The RAAS is pivotal in long-term BP
control
The RAAS is responsible for:maintenance of sodium balance
control of blood volume
control of blood pressure
-
8/13/2019 4. Essential Hypertension
15/46
25/01/2014 15
The RAAS is stimulated by:
fall in BP
fall in circulating volume
sodium depletion
Any of the above stimulate renin release
from the juxtaglomerular apparatus
Renin converts angiotensinogen to
angiotensin I
Angiotensin I is converted to angiotensin IIby angiotensin converting enzyme (ACE)
-
8/13/2019 4. Essential Hypertension
16/46
25/01/2014 16
Angiotensin II is a potent
vasoconstrictor
anti-natriuretic peptide
stimulator of aldosterone release from the
adrenal glands
Aldosterone is also a potent antinatriureticand antidiuretic peptide
Angiotensin II is also a potent hypertrophic
agent which stimulates myocyte and smoothmuscle hypertrophy in the arterioles
-
8/13/2019 4. Essential Hypertension
17/46
25/01/2014 17
Myocyte and smooth muscle hypertrophy:
are both poor prognostic indicators in patientswith hypertension
partially explain why hypertension and the risks
of hypertension persist in some patients despite
treatment
Both the sympathetic and RAAS are key
targets in the treatment of hypertension
-
8/13/2019 4. Essential Hypertension
18/46
25/01/2014 18
Aetiology of essential hypertension
The aetiology of hypertension is
Polygenic
Major genes
Poly genes
Polyfactorial
Environment Individual and Shared
-
8/13/2019 4. Essential Hypertension
19/46
25/01/2014 19
Likely causes:
Increased reactivity of resistance vesselsand resultant increase in peripheral
resistance
as a result of an hereditary defect of the smooth
muscle lining arterioles
A sodium homeostatic effect
In essential hypertension the kidneys are unable
to excrete appropriate amounts of sodium for
any given BP. As a result sodium and fluid are
retained and the BP increases
-
8/13/2019 4. Essential Hypertension
20/46
25/01/2014 20
Other factors
Age
Genetics and family history
Environment
Weight
Alcohol intake
Race
-
8/13/2019 4. Essential Hypertension
21/46
25/01/2014 21
AGE
BP tends to rise with age, possibly as a result of
decreased arterial compliance.
Hypertension in the elderly should be treated as
aggressively as in the young. They have more
to loseStudies such as EWPHE, Primary Care
Study,MRC Hypertension in the Older Adult,
SHEP, SYSTEUR and STOP-1 and 2 have
proven that treating both diastolic and systolichypertension in the elderly significantly reduces
stoke and MI.
-
8/13/2019 4. Essential Hypertension
22/46
25/01/2014 22
GENETICS
A history of hypertension tends to run in
families
The closest correlation exists between sibs
rather than parent and childIt is also possible that environmental factors
common to members of the family also have a
role in the development of hypertension
-
8/13/2019 4. Essential Hypertension
23/46
25/01/2014 23
Environment
Mental and physical stress both increase bloodpressure
However removing stress does nor necessarily
return blood pressure to normal values
True stress responders who have very high BPwhen they attend their doctor but low normal
pressures otherwise tend to be highly resistant
to treatment
-
8/13/2019 4. Essential Hypertension
24/46
-
8/13/2019 4. Essential Hypertension
25/46
25/01/2014 25
ALCOHOL
The most common cause oh hypertension in the
young ScotAffects 1% of the population
Small amounts of alcohol tend to decrease BP
Large amounts of alcohol tend to increase BPIf alcohol consumption is reduced BP will fall
over several days to weeks.
Average fall is small 5/3 mmHg
W i ht
-
8/13/2019 4. Essential Hypertension
26/46
25/01/2014 26
Weight
Obese patients have a higher BP
Up to 30% of hypertension is attributable in
part or wholly to obesity
If a patient loses weight BP will fall
In untreated patients a weight loss of 9Kg has
been reported to produce a fall in BP of 19/18mmHg
In treated patients a fall in BP of 30/21 mmHg
has been reported
Weight reduction is the most important non-
pharmacological measure available
-
8/13/2019 4. Essential Hypertension
27/46
25/01/2014 27
Birth Weight
Birth weight is also associated with the
development of hypertension in later life.
The lower the birth weight the higher thelikelihood of developing hypertension and
heart disease
Clearly in-utero factors affect health at alater stage.
-
8/13/2019 4. Essential Hypertension
28/46
25/01/2014 28
Race
Caucasians have a lower BP than black
populations living in the same environmentBlack populations living in rural Africa have a
lower BP than those living in towns
Reasons are not clearPossibly black populations are more susceptible
to stress when living in towns
Respond in different ways to changes in diet
Black populations are genetically selected to be
salt retainers and so are more sensitive to an
increase in dietary salt intake
-
8/13/2019 4. Essential Hypertension
29/46
25/01/2014 29
Secondary Hypertension
5-10% of all hypertension has an
identifiable cause
Removal of the cause does not guarantee
that the hypertension or risk will return to
normal Sustained hypertension produces end-organ
damage to blood vessels, heart and kidney
This type of damage tends to increase BPfurther and so a vicious self-propagating
cycle is established
-
8/13/2019 4. Essential Hypertension
30/46
25/01/2014 30
Causes for Secondary Hypertension
Renal disease
20% of resistant hypertensive patients
chronic pyelonephritis
renal artery stenosis
polycystic kidneys
Drug Induced
NSAIDs
Oral contraceptive
Corticosteroids
-
8/13/2019 4. Essential Hypertension
31/46
-
8/13/2019 4. Essential Hypertension
32/46
25/01/2014 32
The risks of hypertension
The risks of hypertension are well
recognised
Cerebrovascular disease
Thromboembolic
Intra cranial bleed
TIA
Cardiovascular disease
Myocardial infarction
Heart failure
Coronary artery disease
-
8/13/2019 4. Essential Hypertension
33/46
25/01/2014 33
The risks of hypertension
Peripheral vascular disease
Renal failure
-
8/13/2019 4. Essential Hypertension
34/46
25/01/2014 34
The risks of hypertension
A sustained increase in BP increases theload on the heart and blood vessels
This has two effects
Myocardial hypertrophySmooth muscle hypertrophy in the resistance
vessels
Hypertrophy of this type increases thestrength of the heart and vasculature
However it also reduces compliance
-
8/13/2019 4. Essential Hypertension
35/46
Atheromatous disease
-
8/13/2019 4. Essential Hypertension
36/46
25/01/2014 36
Atheromatous disease
Sustained hypertension is associated with
accelerated atheromatous disease of the blood
vessels
Peripheral vascular disease
Coronary artery disease
Cerebrovascular diseaseRenal artery disease
The Heart
MIHeart failure
Angina
-
8/13/2019 4. Essential Hypertension
37/46
25/01/2014 37
Detection and Diagnosis
Initial assessment History
Office blood pressure
ABPM Abdominal ultrasound scan
Inpatient assessment
Assess risk Smoking
Diabetes
Previous pathology
-
8/13/2019 4. Essential Hypertension
38/46
25/01/2014 38
Hypertension
Medication for High Blood
Pressure Diuretics
Rid the body of excess fluids and salt
Beta-blockers
Reduce the heart rate and the work of theheart
Calcium antagonists
Reduce heart rate and relax blood vessels
-
8/13/2019 4. Essential Hypertension
39/46
25/01/2014 39
Hypertension
Medication for High Blood
Pressure Angiotensin II receptor blockers(ACE)
Interfere with the bodies production of
angiotensin, a chemical that causes the
arteries to constrict (narrow)
Vasodialators
Cause the muscle in the wall of the blood
vessels to relax, allowing the vessel to
dialate (widen)
-
8/13/2019 4. Essential Hypertension
40/46
25/01/2014 40
Hypertension
Medication for High Blood
Pressure Sympathetic nerve inhibitors
Sympathetic nerves go from the brain to all
parts of the body, including the arteries
Cause arteries to constrict raising bloodpressure
These drugs reduce blood pressure by
inhibiting these nerves from constricting
blood vessels
-
8/13/2019 4. Essential Hypertension
41/46
25/01/2014 41
Hypertension
Home Blood Pressure
Monitoring Mercury sphygmomanometer
Standard for BP monitoring
No calibration
May be bulky
Need a second person to use machine
May be difficult for hearing impaired or
patients with arthritis
-
8/13/2019 4. Essential Hypertension
42/46
-
8/13/2019 4. Essential Hypertension
43/46
25/01/2014 43
Hypertension
Home Blood Pressure
Monitoring Automatic equipment
Contained in one unit
Portable with easy-to-read digital display
Expensive, fragile
Must be calibrated
Requires careful cuff placement
-
8/13/2019 4. Essential Hypertension
44/46
-
8/13/2019 4. Essential Hypertension
45/46
-
8/13/2019 4. Essential Hypertension
46/46
25/01/2014 46
Thank you for attention!