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Arterial hypertension

Synonym: high blood pressure
abbreviation: aHT
German: arterielle Hypertonie

1 Definition

According to WHO criteria, arterial hypertension is defined as a permanent increase of systolic blood pressure over 140 mmHg, and a diastolic increase to more than 90 mmHg, independent of the situation.

A systolic blood pressure of more than 120 mmHg, or a diastolic blood pressure of more than 80 mmHg is judged as marginal.

2 Epidemiology

The prevalence of arterial hypertension in Western industry nations is relatively high. The findings in different epidemiological studies however partly vary significantly between each other. A study from 2003, which was conducted in 6 European countries, Canada, and the USA, states prevalence of arterial hypertension in Europe at 44% of the population over 35 years of age. For the USA, a prevalence of 28% is stated. As rough approximation, one can say that

  • at an age between 45 and 54 years, 20-30%,
  • at an age between 55 and 64 years, 30-40%,
  • at an age between 65 and 74 years, 40-50%,

of the population in Europe suffer from arterial hypertension.

3 Classification

Arterial hypertension can be classified according to many different aspects, which partly are more based on pathophysiology, partly on clinical findings.

3.1 Classification according to cause

Primary hypertension: Hypertension which develops without visible cause. It is also called essential hypertension. It represents the largest proportion of cases of hypertension in adults (app. 85%). In children, itís exactly the opposite.

Secondary hypertension: This is defined as hypertension that occurs due to another underlying disease, or is caused by detectable factors. Secondary hypertension represents the smaller proportion of cases in adults (app. 15%). In children, itís exactly the opposite. Possible causes include:

Increased blood pressure that is caused by one of the following points is not counted among chronic arterial hypertension:

3.2 Classification according to ESH

ESH ("European Society of Hypertension") classifies hypertension according to the measurement value of blood pressure:

grade systolic pressure diastolic pressure
Grade 1 (mild) 140-159 mmHg 90-99 mmHg
Grade 2 (moderate) 160-179 mmHg 100-109 mmHg
Grade 3 (severe) ≥180 mmHg >110 mmHg

3.3 Classification according to WHO

Hypertension can also be classified according to organ damage of vessels, eyes, heart, kidneys etc. into three grades as per recommendations of the WHO:

Grade Organ damage
Grade I Hypertension without end organ damage
Grade II Hypertension with end organ damage (z.B. hypertensive retinopathy (grade I and II), plaque formation in larger vessels)
Grade III Hypertension with manifest cardiovascular secondary diseases (eg. angina pectoris, myocardial infarction, stroke, PAD)

3.4 Classification according to AWMF

The definitions and classification of the blood pressure values in the guidelines for the treatment of arterial hypertension of the AWMF (German Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V., Association of the Scientific Medical Societies in Germany) follows the definitions of the WHO.

Category systolic (mmHg) diastolic (mmHg)
Ideal blood pressure < 120 < 80
Normal blood pressure 120–129 80–84
High-normal blood pressure 130–139 85–89
Mild hypertension (grade 1) 140–159 90–99
Medium hypertension (grade 2) 160–179 100–109
Severe hypertension (grade 3) ≥ 180 ≥ 110
Isolated systolic hypertension > 140 < 90
  • When a patientís systolic and diastolic blood pressure fall into different categories, the higher category should be applied.
  • Isolated systolic hypertension should be classified into three grades, depending on the level of systolic blood pressure:
    • Grade 1: 140-159
    • Grade 2: 160-179
    • Grade 3: ≥180 mmHg
  • In isolated systolic hypertension, there is a special risk that results from suspiciously low diastolic blood pressure (eg. 60-70 mmHg).

3.5 Further classifications

  • Form of the increase in blood pressure
    • Isolated systolic hypertension
    • Isolated diastolic hypertension
    • Combined systolic-diastolic hypertension
  • Chronological sequence of hypertension

4 Pathogenesis

The pathogenesis of primary hypertension is so complex that it could not be fully explained up to now. A reason for that is that blood pressure is affected by many different factors. These included among others the circulating blood volume, blood viscosity, cardiac output, vascular elasticity, vessel cross section and hormonal (renin) as well as neuronal stimulation of the vaso-tonus.

You can differentiate between the following pathogenetic forms:

4.1 Cardiac output hypertension

Here, cardiac output is not increased by influences from the heart. Cardiac output hypertension is prominent in hyperthyroidism. Here, the thyroid hormones stimulate the increased expression of beta-receptors, which (significantly) eases the katecholamine attack on the corresponding receptors of the heart.

4.2 Resistance hypertension

Here, blood pressure is increased by vasoconstriction. This can be observed in kidney diseases among others, where the renin-angiotensin-aldosterone system is increasingly activated.

4.3 Elasticity hypertension

This form of hypertension is based on a decrease of elasticity in the arterial system ñ with normal peripheral resistance. The volume elasticity coefficient of the arterial vascular system is increased its pressure reservoir function decreases. This reduces the blood volume storage capability of the vascular system. Clinically, this shows in a greater blood pressure amplitude: Systolic pressure increases, while diastolic pressure remains rather low. Elasticity hypertension is eg. caused by arteriosclerosis of the aorta and the larger arteries.

4.4 Volume hypertension

In case of volume hypertension, blood pressure rises subsequent to an increase of the volume of blood within the vascular system. This needs to be seen separately from edemas, where fluids gather in extravasal tissue. In renal failure, volume hypertension develops due to the increasing inability to further transport the fluids (filter function of the kidneys).

5 Risk factors

6 Symptoms

Hypertension usually develops asymptomatically and often causes only uncharacteristic complaints in moderately increased blood pressure values:

In strongly increased blood pressure, the following symptoms can add:

When hypertension is not detected by blood pressure control, it often is only recognized due to its late consequences (silent death).

7 Diagnostics

The diagnosis "hypertension" is firstly made due to the repeated blood pressure measurement on both arms. As thresholds, according to a definition of the WHO, a value of over 140 mmHg is determined for the systolic blood pressure, and a value of 90 mmHg for the diastolic pressure. However, a singular measurement over these standard values doesnít justify a diagnosis of hypertension. It is only confirmed, when at three measurements at different times of day on 3 different days, increased values over the above stated standard are observed. Each measurement of the blood pressure should be carried out at rest, i.e. after 3-5 minutes of the patient being seated. Moreover, you need to make sure that both arms are positioned at the height of the heart.

The basic program of hypertension diagnostics additionally comprises:

8 Therapy

8.1 Causal therapy

With causal therapy, you try to eliminate the causes responsible for the arterial hypertension. Lifestyle-changing measures play an essential part in this form of therapy. This includes:[1]

  • Limitation of salt intake
    • 5-6 grams per day
  • Limitation of alcohol consumption
    • no more than 20-30 grams of alcohol per day in men
    • no more than 10-20 grams of alcohol per day in women
  • Increased consumption of vegetables, fruits and milk products
    • Here, the so-called "DASH diet" has proved itsself (dietary approach to stop hypertension)[2]
  • Weight reduction
  • Regular movement
    • At least 30 minutes of moderate dynamic training on 5 - 7 days per week
  • Quitting smoking

8.2 Drug therapy

The following table shows differential drug therapies of arterial hypertension.[3]

Indication Therapy
Middle-aged hypertensive patients without concomitant diseases Beta blockers, ACE-inhibitors, AT1-antagonists
Elderly hypertensive patients without concomitant diseases Thiazide diuretics, calcium channel blockers of the dihydropyridin type
A) Proven additional effects/indications
Diabetes mellitus with proteinuria ACE-inhibitors, AT1-antagonists
Heart failure ACE-inhibitors, diuretics, beta blockers (gradually increasing dosage!)
Isolated systolic hypertension Diuretics (preferred), calcium antagonists (with longterm effect)
Myocardial infarction Beta blockers (without ISA), ACE-inhibitors and AT1-antagonists (in systolic dysfunction and left ventricular hypertrophy. ACE-inhibitors and AT1-antagonists also prevent remodelling and fibrosis in addition to ischemic myocardial areas).
B) Favorable effects possible:
Angina pectoris Beta blockers without ISA, calcium antagonists (attention: dihydropyridines are contra-indicated in unstable Angina pectoris)
Atrial tachycardia, atrial fibrillation Beta blockers, clonidin, calcium antagonists (type verapamil and diltiazem)
Diabetes mellitus ACE-inhibitors, AT1-antagonists, cardio-selective beta blockers (low dose), alpha-recceptor blockers
Migraine Beta blockers (without ISA), calcium channel blockers
Renal failure ACE-inhibitors (attention: renosvascular hypertension and serum creatinine ≥ 3mg/dl)
B) Adverse effects possible:
Obstructive ventilation disorders Beta blockers
Diabetes mellitus (non-selective) beta blockers, high-dosage diuretics, calcium antagonists
Gout Diuretics
Heart failure Calcium antagonists
AV conduction defects Beta blockers, verapamil type calcium antagonists
PAD (non-selective) beta blockers
Renal failure Potassium-saving drugs, thiazids (not when serum creatinine is >2 mg/dl)
Renal artery stenosis ACE-inhibitors, AT1-antagonists

9 References

  1. Guidelines for the management of arterial hypertension. ESC Pocket Guidelines
  2. Your Guide to Lowering Blood Pressure National Institutes of Health
  3. The Sixth Report Of The Joint National Committee On Prevention; Detection, Evaluation, and Treatment Of High Blood Pressure (JNC VI) (National Institutes of Health, Lung and Blood Institute, National High Blood Pressure Education Program, NIH Publication No. 98-4080, November 1997)

10 Literature

11 Weblinks

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