lecture for undergraduate about systemic arterial hypertension. entailed a simplified approach from definition to management including hypertensive emergencies and urgencies
1. Arterial Hypertension
Motea Al-Awlaqi, MD
Assistant professor of cardiology, Aden University
Cardiologist Consultant, Al-Gamhoriah General Teaching Hospital
2. Introduction
Hypertension is one of the common pathological entities in the world
Hypertension is associated with the development and exacerbation of a variety of
cardiovascular disease, as well as the morbid and fatal outcome
The systolic blood pressure increases in a linear fashion throughout life, whereas, the
diastolic blood pressure increases until 50 years of age and falls thereafter
Hypertension remains the major preventable cause of cardiovascular disease(CVD) and
all-cause death globally
The overall prevalence of hypertension in adults is around 30 - 45%, with a global age-
standardized prevalence of 24 and 20% in men and women, respectively, in 2015
This high prevalence of hypertension is consistent across the world, irrespective of
income status, i.e. in lower, middle, and higher income countries
Hypertension becomes progressively more common with advancing age, with a
prevalence of >60% in people aged >60 years
Fewer than 30% of people with hypertension have the problem under control
3. Definition of hypertension
Hypertension’ is defined as the level of BP at which the benefits of treatment (either with
lifestyle interventions or drugs) unequivocally outweigh the risks of treatment, as
documented by clinical trials
Hypertension is defined as office SBP values > 140 mmHg and/or diastolic BP (DBP)
values > 90 mmHg
Isolated systolic hypertension defined as elevated SBP (>140 mm Hg) and low DBP (< 90
mm Hg) is common in young and in elderly people. In young individuals, including
children, adolescents and young adults, isolated systolic hypertension is the most
common form of essential hypertension
6. Etiology of Hypertension
ESSENTIAL HYPERTENSION SECONDARY HYPERTENSION
Account for about 95% of cases
No cause can be identified
(primary or essential HTN)
The onset usually b/w the age 25-
55 years
It is uncommon before the age of
20
Account for 5% of cases
A cause can be identified
Most of the patients are young
Most cases due renal, endocranial
causes and COA
7. Risk factors for primary hypertension
Genetic factors
Obesity
Lack of exercise
Heavy alcohol intake
Excess salt intake
Cigarette smoking
Polycythemia
NSAID
Low potassium intake
Sympathetic overactivity
Insulin resistance
9. Patient characteristics that should raise the suspicion of
secondary hypertension
Younger patients (<40 years) with grade 2 hypertension or onset of any grade of hypertension in
childhood
Acute worsening hypertension in patients with previously documented chronically stable normotension
Resistant hypertension
Severe (grade 3) hypertension or a hypertension emergency
Presence of extensive HMOD
Clinical or biochemical features suggestive of endocrine causes of hypertension or CKD
Clinical features suggestive of obstructive sleep apnoea
Symptoms suggestive of phaeochromocytoma or family history of phaeochromocytoma
10. Pathophysiology of essential hypertension
The pathophysiology of essential hypertension is incompletely understood, but is
thought to be related to one or more of the following mechanisms:
1. Defects in RAAS
2. Disturbed autonomic function
3. ↑ COP may be the initial step and subsequently causes ↑ PVR
4. Salt sensitivity: some individuals are salt sensitive lead to ↑ BP. The cause
may be genetic defect in the ability of the kidney to excrete sodium load
5. Defective pressure naturesis: the normal Kidney respond to ↑ BP by ↑ sodium
excretion. If this mechanism is defective the renal role in regulating BP is
diminished
6. Insulin resistance and metabolic syndrome; this lead to compensatory
hyperinsulinemia which causes obesity, increased sympathetic activity,
increased sodium absorption in the renal tubules and dyslipidemia (↑ TG and
↓ HDL)
12. Clinical features
Symptoms
Hypertension is called a "silent killer". Most people with hypertension are asymptomatic
When symptoms do occur, they can include
- headache (suboccipital pulsating headache characteristically occurring early in the
morning and subsiding during the day, is characteristic but any type of headache may
occur)
- Nosebleeds, irregular heart rhythms, vision changes, and buzzing in the ears
Severe hypertension can cause fatigue, nausea, vomiting, confusion, anxiety, chest
pain, and muscle tremors
Symptoms of secondary causes of hypertension if present. For example
pheochromocytoma may present with episodes of hypertension along with anxiety,
palpitation, profuse perspiration, pallor, tremor, nausea and vomiting
Symptoms of complication such as heart failure, stroke and renal failure
13. Clinical features
signs
High BP may be the only sign in the majority of patients
Features of the cause of hypertension
- Abdominal bruit- renovascular hypertension
- Radiofemoral delay- COA
- Enlarged kidneys – PCKD
- Characteristic facies and habitus of Cushing's syndrome
Evidence of risk factors for hypertension
- Central obesity
- Hyperlipidaemia
Signs due to complication of hypertension
- Signs of LVH-↑ A2, S4
- AF (due to diastolic dysfunction or CAD)
- Signs of LVF (in absence of CAD or renal impairment)
- The optic fundi are often abnormal
- There may be evidence of generalised atheroma or specific complications, such as
aortic aneurysm, PAD or stroke
14. Arterial Hypertension as a risk factor
• Hypertension is a highly prevalent risk factor for cardiovascular disease
• Hypertension plays a major etiologic role in the development of cerebrovascular disease,
ischemic heart disease, cardiac and renal failure
15. Assessment of global cardiovascular risk in arterial
hypertension
• Grades of hypertension
• Total cardiovascular risk (coexistence different risk factors, organ damage, concomitant
diseases)
17. Hypertension Diagnosis
• Establishing BP values
• Identyfying secondary causes of AH
• Searching for :
- other risk factors
- subclinical organ damage
- concomitant diseases
- accompanying CV and renal complications
Diagnostic evaluation in arterial hypertension
18. Hypertension Diagnosis
The measurement of BP in the office or clinic is most commonly the basis for hypertension
diagnosis and follow-up
Auscultatory or oscillometric semiautomatic or automatic sphygmomanometers are the
preferred method for measuring BP in the doctor’s office
Whenever possible, the diagnosis should not be made on a single office visit. Usually 2–3
office visits at 1–4-week intervals (depending on the BP level) are required to confirm the
diagnosis of hypertension
The diagnosis might be made on a single visit, if BP is >180/110 mmHg and there is evidence
of cardiovascular disease (CVD)
If possible and available, the diagnosis of hypertension should be confirmed by out-of-office BP
measurement
Unattended office blood pressure: Multiple automated BP measurements taken while the
patient remains alone in the office provide a more standardized evaluation but also lower BP
levels than usual office measurements with uncertain threshold for hypertension diagnosis.
Confirmation with out-of-office BP is again needed for most treatment decisions
Improper measurement of office BP can lead to inaccurate classification, overestimation of a
patient’s true BP, and unnecessary treatment
Office Blood Pressure Measurement
21. Hypertension Diagnosis
Out-of-office BP measurements (by patients at home or with 24-hour ambulatory blood
pressure monitoring [ABPM]) are more reproducible than office measurements, more
closely associated with hypertension-induced organ damage and the risk of
cardiovascular events and identify the white coat and masked hypertension phenomena
Out-of-office BP measurement is often necessary for the accurate diagnosis of
hypertension and for treatment decisions. In untreated or treated subjects with office BP
classified as high-normal BP or grade 1 hypertension (systolic 130–159 mm Hg and/or
diastolic 85–99 mm Hg), the BP level needs to be confirmed using home or ambulatory
BP monitoring
Out-of-Office Blood Pressure Measurement
22. Investigations
A decision to embark on antihypertensive therapy effectively commits the patient to life-long
treatment, so readings must be as accurate as possible
The objectives are to:
• Confirm the diagnosis by obtaining accurate, representative BP measurements
• Identify contributory factors and any underlying causes
• Assess other risk factors and quantify cardiovascular risk
• Detect any complications that are already present
• Identify comorbidity that may influence the choice of antihypertensive therapy
25. Specialized investigation of hypertension
Chest X-ray: to detect cardiomegaly, heart failure, coarctation of the aorta
Ambulatory BP recording: to assess borderline or ‘white coat’ hypertension
Echocardiogram: to detect or quantify left ventricular hypertrophy
Renal ultrasound: to detect possible renal disease
Renal angiography: to detect or confirm the presence of renal artery stenosis
Urinary catecholamines: to detect possible phaeochromocytoma
Urinary cortisol and dexamethasone suppression test: to detect possible Cushing’s
syndrome
Plasma renin activity and aldosterone: to detect possible primary aldosteronism
26. Differential Diagnosis
It is important to identify white coat hypertension and masked hypertension correctly as over- or under-
treatment of hypertension can have significant morbidity and mortality.
White coat Hypertension
•Consistently elevated office blood pressure but normal out-of-office blood pressure
Masked Hypertension
•Consistently elevated out-of-office blood pressure but normal office blood pressure
Psuedohypertension
• a measurement of high BP value in the presence of normal intraluminal BP because of
noncompressible arteries
•This causes a false elevation of blood pressure reading
•Use of standing blood pressure measurement can help to differentiate pseudo-hypertension from true
hypertension
•The Osler maneuver (palpable radial or brachial artery when the cuff inflated above the SBP) may be
used although sensitivity and specificity are not very high
•Patients with poorly controlled blood pressure should be evaluated for pseudo-hypertension prior
to being labeled as resistant hypertension.
27. Complications of hypertension
The adverse effect of hypertension principally involves the CNS, retina, heart and kidneys
A) CNS
1. Diffuse cerebral atherosclerosis
2. Lacunar infarct
3. Stroke (ischemic or hemorrhagic)
4. Hypertensive encephalopathy: it is characterised by severe hypertension with neurological
symptoms e.g. transient disturbances of speech or vision, disorientation, fits and
unconsciousness
5. ICH
6. Subarachnoid hemorrhage
7. Muti-infarct dementia
29. Complications of hypertension
C) Heart
- LVH
- LV diastolic dysfunction
- LV systolic failure
- IHD
D) Kidneys
- Nephrosclerosis (hypertensive nephropathy)
- Proteinuria
- Progressive renal failure
- Renal artery aneurysm
E) Vascular
- Accelerated atherosclerosis
- Hge from rupture of small vessels (e.g. epistaxis)
- Dissecting aneurysm of aorta
- PAD- ischemia of LL or intermittent claudication
30. Management of hypertension
The management of hypertension typically involves both lifestyle modifications and
pharmacologic therapies
Both are required to achieve target blood pressure
Lifestyle modifications are initiated before pharmacologic interventions unless:
- The blood pressure is stage 2
- Target organ disease is present, or
- A comorbid condition exists which is favorably influenced by a specific antihypertensive drug
31. Lifestyle modification
Weight reduction. Target body mass index of 18.5 to 24.9 kg/m2. Average systolic blood
pressure (SBP) reduction of 5 to 20 mm Hg per 10 kg weight loss.
Moderate alcohol intake. Men: limit to =2 drinks (15 mL of ethanol). Women and lighter weight
persons: limit to =1 drink per day. Average SBP reduction of 2 to 4 mm Hg.
Regular aerobic physical activity. Brisk walking at least 30 minutes per day, most days of the
week. Average SBP reduction of 4 to 9 mm Hg.
Reduce dietary sodium intake. Decrease to =100 mmol/ day (2.4 g of Na or 6 gm of NaCl).
Average SBP reduction of 2 to 8 mm Hg.
Dietary Approaches to Stop Hypertension (DASH) diet. Adopt a diet rich in fruits, vegetables,
and low fat dairy products with reduced content of saturated and total fat. Average SBP
reduction of 2 to 8 mm Hg.
32. Pharmacological therapy
A variety of drugs are available to manage the patient with hypertension. These agents can be
classified into seven categories (prototypes)
Diuretics (hydrochlorothiazide).
Adrenergic inhibitors
- α-blocker: prazosin
- ß-blocker: Bisoprolol
- Mixed: labetalol
- centrally acting: clonidine
Direct vasodilators (hydralazine).
Calcium channel blockers (CCBs), such as nifedipine.
Converting-enzyme inhibitors (CEI) such as captopril
Angiotensin I (AT1)-receptor blockers (losartan).
Direct inhibitors of renin (aliskiren)
35. Benefits of Lowering BP
Average reduction
Stroke incidence 35–40%
Myocardial infarction 20–25%
Heart failure 50%
36. Aim of antihypertensive therapy
• The primary goal of treatment is to achieve maximum reduction in the long-term total risk
of CV disease
• For this reason lowering BP therapy (at least < 140/90 mm Hg) and treatment of all
reversible risk factors are indicated
• In diabetes and in high and very high risk patients BP target should be at least < 130/80
mmHg
42. Resistant hypertension
Hypertension is defined as resistant to treatment when the recommended treatment
strategy fails to lower office SBP and DBP values to <140 mmHg and/or <90 mmHg,
respectively, and the inadequate control of BP is confirmed by ABPM or HBPM in
patients whose adherence to therapy has been confirmed
The recommended treatment strategy should include
- Appropriate lifestyle measures and
- Treatment with optimal or best-tolerated doses of three or more drugs, which should
include a diuretic, typically an ACE inhibitor or an ARB, and a CCB.
- Pseudo-resistant hypertension and secondary causes of hypertension should also have
been excluded
43. Characteristics of patients with resistant hypertension
Resistant hypertension is associated with
- older age (especially >75 years)
- male sex
- black African origin
- higher initial BP at diagnosis of hypertension, highest BP ever reached during the
patient’s lifetime
- frequent outpatient visits
- Obesity
- Diabetes
- atherosclerotic disease and HMOD, CKD, and
- a Framingham 10 year coronary risk score >20%
44. Causes of resistant hypertension
1. Pseudo-resistant hypertension
- Poor adherence to prescribed medicines
- White-coat phenomenon
- Poor office BP measurement technique
- Marked brachial artery calcification
- Clinician inertia, resulting in inadequate doses or irrational combinations of BP-lowering
drug therapies
2. Other causes of resistant hypertension
- Lifestyle factors, such as obesity or large gains in weight, excessive alcohol
consumption, and high sodium intake
- Intake of vasopressor or sodium-retaining substances, drugs prescribed for conditions
other than hypertension, some herbal remedies, or recreational drug use (cocaine,
anabolic steroids, etc.)
- Obstructive sleep apnoea (usually, but not invariably, associated with obesity)
- Undetected secondary forms of hypertension
- Advanced HMOD, particularly CKD or large-artery stiffening
45. Hypertensive crisis
Hypertensive crisis is a generic term refer to the sudden or rapid development of severe
hypertension (SBP > 180 mmHg and/or DBP > 120 mmHg) that have the potential to
cause target organ damage (heart, vascular, kidneys, eyes and brain)
Hypertensive crises represents 3% of all medical urgencies, with a prevalence of 24%
and 76%, for hypertensive emergencies and urgencies, respectively
Prompt recognition, evaluation and appropriate treatment of these crises are critical to
prevent high morbidity and mortality
Risk factors include:
- Female sex
- Obesity
- High BMI
- Hypertensive or coronary heart disease
- Higher number of antihypertensive drugs and,
- Most importantly, nonadherence to medication
46. Hypertensive emergency
Hypertension emergencies are situations in which substantially elevated BP is
associated with acute HMOD, which is often life-threatening and requires immediate but
careful intervention to lower BP, usually with intravenous (i.v.) therapy
Typical presentations of a hypertension emergency are:
- Patients with malignant hypertension
- Patients with severe hypertension associated with other clinical conditions who are likely
to require an urgent reduction of BP, e.g.
• acute aortic dissection
• acute myocardial ischaemia, or
• acute heart failure
• ICH
Patients with sudden severe hypertension due to phaeochromocytoma, associated with
organ damage
Pregnant women with severe hypertension or preeclampsia
The definition intentionally are devoid of any absolute BP numbers because the level at
which the individual develop TOD can vary depending on the clinical substrate and the
rapidity of which BP rise
47. Hypertensive emergency
Malignant hypertension
A specific form of hypertensive emergency Characterized by Severe BP elevation
(commonly >200/120 mm Hg) associated with advanced bilateral retinopathy (flame
haemorrhages and/or papilloedema), microangiopathy, and disseminated intravascular
coagulation, and can be associated with encephalopathy (in about 15% of cases), acute
heart failure, and acute deterioration in renal function
The hallmark of this condition is small artery fibrinoid necrosis in the kidney, retina, and
brain.
The term ‘malignant’ reflects the very poor prognosis for this condition if untreated
Hypertensive encephalopathy: Severe BP elevation associated with lethargy, seizures,
cortical blindness and coma in the absence of other explanations
50. Management of hypertensive emergency
Prompt BP control within minutes or a few hours by intravenous administration of
antihypertensive drugs
Lower MAP initially up to 25%
Prompt intravenous administration of short-acting and titratable drugs is preferred in the
first few minutes of treatment
- Aim for DBP of 100-105 mmHg within 6-8 hrs
- Avoid lowering of SBP below 160 mmHg in the acute setting (given changes in cerebral
autoregulation)
- Exception: aortic dissection where goals of SBP 120 mmHg, MAP 80 mmHg, achieved
over 5-10 minutes
- Reduce BP to goal on oral medications, gradually over 2-3 months
51. Hypertensive urgency
It is an acute increase in BP in the absence of, or with minimal, target end-organ damage
The decrease in BP may be obtained in hours or few days by oral anti-hypertensives.
Most cases do not need hospitalization and are managed effectively on outpatient follow-
up
(a) Immediate goal—lower blood pressure within 24–72 h
(b) Treatment setting—clinical discretion is required
(c) Medications—oral medications with rapid onset of action; occasionally intravenously
Goals of decreasing BP
The relationship between BP and cardiovascular (CV) and renal events is continuous, making the distinction between normotension and hypertension, based on cut-off BP values, somewhat arbitrary.
However, in practice, cut-off BP values are used for pragmatic reasons to simplify the diagnosis and decisions about treatment. Epidemiological associations between BP and CV risk extend from very low levels of BP [i.e. systolic BP (SBP) >115 mmHg]
In young individuals, including children, adolescents and young adults, isolated systolic hypertension is the most common form of essential hypertension
However, it is also particularly common in the elderly, in whom it reflects stiffening of the large arteries with an increase in pulse pressure (difference between SBP and DBP).
The relationship between BP and cardiovascular (CV) and renal events is continuous, making the distinction between normotension and hypertension, based on cut-off BP values, somewhat arbitrary.
However, in practice, cut-off BP values are used for pragmatic reasons to simplify the diagnosis and decisions about treatment. Epidemiological associations between BP and CV risk extend from very low levels of BP [i.e. systolic BP (SBP) >115 mmHg]
Genetic factors: children of hypertensive patients more prone to develop hypertension
Hypertension is called a "silent killer". Most people with hypertension are unaware of the problem because it may have no warning signs or symptoms. For this reason, it is essential that blood pressure is measured regularly
Importantly, only diuretics, ß-blockers, and CEI have been proven to reduce morbidity and mortality in hypertension. In addition, it is important to base the initial choice of therapy on a patients comorbid conditions. For example, a patient with a history of cardiovascular disease will likely benefit from ß-blocker therapy, whereas these agents would be contraindicated in the setting of chronic obstructive pulmonary disease
The definition intentionally are devoid of any absolute BP numbers because the level at which the individual develop TOD can vary depending on the clinical substrate and the rapidity of which BP rise For example a patient with chronic longstanding poorly controlled HTN may tolerate 230/120 mmHg without evidence of acute TOD while a ypung pat with AGN may develop hypertensive encephalopathy at lowe r level
To maintain adequate and stable blood low to the vital organs like brain, heart, and kidneys, autoregulation of vasculature is of prime importance. The threshold of hypoperfusion is approximately 20–25% lower than the existing blood pressure and this physiologic rationale is behind the recommendation to limit the initial blood pressure reduction to 20–25% of pretreatment values