Arterial hypertension

Epidemiology

Among 972 million hypertensive adults, 333 million, is 37,3% of their population, come from the countries " développés" , and 639 million, is 22,9% of their population, result from the countries " in développement".

Reaching 10 to 15% of the French population (8 million people treated), arterial hypertension presents true public health problems.

Indeed, the rise in the blood-pressure results in an increase in risks of morbidity (risk of the complications) and of mortality (risk of death) especially because of its cardiovascular, neurological and renal complications; this risk can be reduced by a treatment Antihypertenseur adapted and prevented by the compliance with certain hygiéno-dietetic rules.

Definition

The blood Pressure must be measured in sitting position or lengthened, after 5 to 10 minutes of rest. The values must be found high on three different occasions so that one can speak about arterial hypertension (or HTA). The doctor measures two numbers:

that of the systolic blood pressure or NOT which reflect the pressure at the time of the contraction of the left ventricle (Systole),
the diastolic blood pressure or PAD which reflects the pressure during the relieving of the left ventricle (Diastole)
an average blood pressure calculates starting from the two first.

Measurements are expressed in centimetre or millimetre of mercury (Hg). The blood-pressure is regarded as preceding an arterial hypertension for values of the systolic blood pressure ranging between 120 and 139 mm Hg and/or of the diastolic blood pressure ranging between 80 and 89 mm Hg.

The concept of arterial hypertention limits does not exist more.

Si of the increased values is found only occasionally, one then speaks about unstable HTA which does not require whereas a simple monitoring, possibly accompanied by hygiéno-dietetic measurements.

One speaks about effect white blouse if the tension is high to the cabinet of the doctor and normal in the life of the every day. This increase in the pressure is secondary with the stress of the consultation and is not abnormal.

On the contrary, one speaks about masked HTA when the figures tensionnels are normal to the consulting room of the doctor and that they are high differently.

This definition of arterial hypertension rests in fact on " the acceptabilité" of a risk rather than on the " normalité" of a value.

Arterial hypertension is thus not a disease but represents a risk factor which, if it is treated, makes it possible to avoid, to a certain extent, of the complications.

The risk increases with the rise in the blood-pressure and it is desirable to have figures tensonniels low possible. However, the the World Health Organization (WHO) fixed thresholds, by holding account at the same time tensionnels risks and disadvantages related to the treatments.

A tension is thus regarded as normal:

if the systolic blood pressure is lower than 140 millimetre of mercury (Hg),
and if the diastolic blood pressure is lower than 90 millimetre of Hg.

Chiffres limiting of the various levels of hypertension

Measurement techniques

See article blood Pressure.

Causes

In 90% of the cases, arterial hypertension is known as essential: no known cause can be found in this case.
In 10% of the cases, arterial hypertension is secondary: several causes can be at the origin of a hypertension, some being curable in a final way:

Renal causes: 4%

Impaired renal function (secondary with a renal Polykystose, a Glomerulonephritis, a Pyelonephritis…).
renal Affection unilateral nonvascular (unilateral pyelonephritis, Tuberculosis, congenital hyperplasy).
Sténose of the renal artery (by Athérome or Fibrosis). It follows a hypoperfusion of the renal parenchyma on the side reached, with, for consequence, an increase in activity of the system Rénine - Angiotensine - Aldostérone, causing a salt and retention of water as well as a vasoconstriction of the Artère S.

Surrénaliennes causes

the Phéochromocytome. It is about a Tumeur secreting in excess of the Catécholamine S. These substances increases the heart rate, the force of contraction of the Cœur and involves a vaso constriction of the arteries, its three elements causing a rise of the figures tensionnels. The tumor, generally surrénalienne, can however have other localizations. The symptoms associate, with the tensionnelles pushes, of the headaches, sweats and from the Palpitation S. the diagnosis possible by the biological proportioning of is derived from the Catécholamine S, in particular the vanylmandelic Acide, in the Sang or in the Urine S. the scanner surrénalien or the Scintigraphie makes it possible to locate the tumor (topographic diagnosis).
the Syndrome of Cushing (by tumor or bilateral hyperplasy of the suprarenals ) involves an important secretion of Cortisol or its derivative. The signs are in general evocative: érythrose (redness) of the face…
the Syndrome of Idiot involves a secretion of the Aldostérone in excess, causing a consecutive retention of water to a sodium retention, and an escape of Potassium. The element directing the diagnosis is the observation of a Hypokaliémie (drops potassium rate in blood). This hyperaldosteronism , measurable in blood and the urines, is known as primary because it is not due to the increase in the Rénine (normal level or low of the latter in blood). He is opposed to the secondary hyperaldosteronisms (high aldosterone and renin) as one sees it in the event of sténose of a renal artery.

Intoxication by the glycyrrhizine

The Glycyrrhizine or licorice comes from the root of the Réglisse. It acts on the inhibition of an enzyme, the 11β-hydroxystéroïde deshydrogénase (standard 2), normally presents to the level certain cells of the kidney to metabolize the Cortisol in Cortisone in order to let the Aldostérone control the sodium reabsorption on its receiver (the Récepteur of mineralocorticoid the). By inactivant the action of the 11β-hydroxystéroïde deshydrogénase (standard 2), the licorice allows the permanent activation of the receiver of the aldosterone by cortisol, and thus a not controlled sodium reabsorption. The excess of licorice reproduces the table of a Adénome of Idiot. The intoxication is secondary with the abundant consumption (higher than one gram per day of glycyrrhizine) of drinks containing liquorice (for the majority of the pastis without alcohol ) or of solid products (sticks of liquorice…).

The aortic coarctation

The congenital contracting (of birth) of the junction between horizontal Aorta and downward aorta (aortic isthmus) involves:

an increase in the blood pressure upstream of the contracting, in particular on the level of the two arms,
an arterial pressure decrease downstream, appearing by femoral Pulses or not with difficulty perceptible.

This diagnosis is to be evoked systematically in front of any hypertension of the child.

Pregnancy

Arterial hypertension, appearing at a expectant mother is called gravidic arterial Hypertension . The precise mechanism is not elucidated but is not called upon hormonal phenomena and probably immuno-allergic.

Other causes

endocriniennes : Hyperthyroïdie, Hypothyroïdie, Acromégalie, Hyperparathyroïdie and them surrénaliennes causes already quoted above.
medicamentous: corticothérapie and hormones
a cerebral tumor or a Cerebral vascular accident.

Supporting causes

In the large majority of the cases, the precise mechanism of the HTA remains unknown. One can however determine a certain number of circumstances statistically associated to the HTA. It is what is called a risk factor . This term implies that the causal link is not drawn up (only statistical risk). The coexistence attends of several of these factors at the same patient, in fact a multifactorielle disease .

The age

The blood pressure increases with the age. This increase is continuous for the systolic , whereas the diastolic drops after about sixty, probably by a mechanism of rigidification of the Artère S. Ainsi, less than 2% of the subjects of less than 20 years are hypertensive, whereas they are more than 40% after 60 years.

The sex

The level tensionnel of the men is higher than that of the women up to 50 years, then there is inversion beyond.

Heredity

There exists a genetic determinism of the essential HTA, whose composite nature was highlighted.

The food (of which the salt excess)

factor more studied has be consumption of Salt food (NaCl) whose importance could, if not to start, at least to maintain a HTA. The salt excess would be responsible for 25.000 deaths per annum in France (75 000 cardiovascular accidents). The ion Sodium (Na⁺) would play a crucial role in the sensitivity to salt of the hypertensive ones. The report/ratio Sodium/Potassium could constitute a determining factor. In any case the reduction of the consumption of Sodium chloride (from 30 to 35% over 30 years) in Finland seems well a major factor of the fall of more than 1 point of the blood Pressure average of the population, and by there of the fall of more than 75% of the cardiovascular Mortalité at the people of less than 65 years, and of the increase in the Life expectancy from 6 to 7 years. Other authors allot a role quite as important to the ion Chlore (Cl^-) or even, in certain forms of hypertension, with the ion Calcium (Ca⁺⁺).
the alcohol consumption in chronicle involves an increase in level tensionnel. The heavy drinkers have a rise in the systolic pressure of more than 1 cm Hg, on average, compared to the not-drinkers.
the consumption of fatty-acids poly-unsaturates has an opposite relationship to the level tensionnel.
the consumption of Café is accompanied by an increase in the tension but the effect is tiny because of the development of one tolerance to the Caféine.
the consumption of Liquorice; to see intoxication by the Glycyrrhizine higher.

The weight

There exists a strong correlation between the Indice of body mass (index of ponderal overload, bringing back the weight to the size) and the level tensionnel.

On the other hand, a Régime hypocaloric at obese hypertensive is accompanied by a fall of the tension.

Diabetes

The subjects diabetics have, on average, a blood-pressure higher than in the remainder of the population.

Stress

A acute Stress is accompanied by a transitory increase in the tension. A chronic stress, or rather, certain ways in which the individual reacts vis-a-vis a chronic stress, seems to support a durable rise in the blood pressure.

Physical effort and sedentariness

The increase in the figures tensionnels to the effort constitutes an acute physiological reaction completely normal.

A contrario, the chronic effect of an adapted physical drive is generally accompanied by a lowering of the blood pressure at rest. A lower blood pressure at the subject trained compared to the sedentary subject is generally noted.

Other factors

the Bruit involves a rise in the blood-pressure.
the Altitude: the populations living in altitude have a level tensionnel low than those living with the sea level.
the season: the blood pressure is higher in winter.
sleep disorders: the subjects buzzers are twice more often hypertensive than the not-buzzers.
the estro-progestative pill increases the figures tensionnels.

Demonstrations

Many hypertensive does not present any Symptôme and hypertension is then a systematic discovery of examination or consultation moved by another thing.

In certain cases, symptoms can translate the consequence of the rise in the tension over the organization. Although nonspecific, the principal symptoms being able to be met at the time of a hypertension are:

of the Cephalgia S (headaches): they are especially characteristic of a serious hypertension. They are classically present as of the morning, in the occipital area (nape of the neck and above),
of the Acouphène S (auditive whistles), of the Phosphène S (perception of luminous points),
of the Vertiges,
of the Palpitation S (feeling of increase in the Cardiac rhythm),
a Asthénie (feeling of tiredness),
a Dyspnée (difficulties of breathing),
a épistaxis (nosebleed), a Hématurie (presence of blood in the urines).

Signs can be characteristic of a causal affection (Maladie of Cushing, Phéochromocytome…), for example: Cephalgia S (headaches), Sweat S, Palpitation S in the Phéochromocytome. In other cases, the symptoms met are the consequence of a complication.

Complications

If the HTA is not controlled by a treatment, complications can occur. It is important to specify that hypertension itself is not a disease: it is only one supporting factor. In other words, its existence is neither necessary nor sufficient to see the diseases developing at the individual. On a population scale, hypertension is a major public health issue. On an individual scale, it has only one rather low predictive value on the development of vascular problems. They can be:

the consequence " mécanique" blood pressure increased on the vessels (rupture of the latter with Hemorrhage S)
the consequence " mécanique" on the cardiac pump working with high pressures for a long time;
the consequence of the participation in the formation or the growth of the Athérome, blocking more or less gradually the Artery S.

They are especially cardiac, neurological and renal.

Cardiac complications

The extra work of work imposed in the middle of the fact of the increase in the blood pressure involves a Hypertrophie (increase in volume) very precociously ventricular left, being able to be detected by ECG or the cardiac echography. This hypertrophy can regress under a antihypertensor treatment.

More tardily, the cardiac cavities dilate and the contractile function of the Myocarde (cardiac muscle) worsens, revealing then the signs of Cardiac failure.

In addition, the athéroscléreuse attack of the Coronary S as well as the increased requirements out of oxygen for a hypertrophied heart explains the occurred frequent one of a coronary Insuffisance at the hypertensive ones.

The HTA facilitates the formation of plate of athérosclérose, which when it is broken form a thrombus (clot) which can come to be placed on the level of coronary. The coronary one then will be stopped and the cardiac zone normally irrigated by this one gradually will necrose: it is the myocardial infarction.

Neurological complications

Retinal modifications can be observed with the Fond of eye, which makes it possible to follow the vascular attack related to hypertension: Spasm S, contracting of the Small artery S, appearance of Exsudat S or Hemorrhage S, papillary edema…

An attack of the central Nervous system is frequent. It appears in particular by the occurred possible one:

of a hemorrhagic Cerebral vascular accident , by rupture of a cerebral vessel, or ischemic by obstruction of a Artery by Athérome or a Thrombus (consequence of the rupture of a plate of athérome).
of a hypertensive encephalopathy (severe hypertension, disorders of conscience, Rétinopathie with papillary edema, convulsives crises ), in the event of HTA with very high figures;
of a arteriopathic Insanity, by attack diffuses cerebral arteries by Athérome.

Renal complications

On the level of the Kidney S, arterial hypertension is responsible for a Néphro-angiosclérose and supports occurred of a Impaired renal function. The deterioration of the renal function is often very early and moderate, but is likely to worsen gradually.

Other complications

Accidents gravidic (i.e. at the expectant mother). The HTA supports the accidents gravidic: eclampsia, mortality Perinatal E…
various vascular Complications: Aneurism S, aortic Dissection, Artériopathie of the lower extremities,
malignant arterial Hypertension: become rare today because of the possibilities of treatment, the malignant HTA is characterized by a very high blood-pressure with renal, neurological disorders (hypertensive encephalopathy, important deteriorations of the bottom of eye) and cardiac (left ventricular insufficiency with acute edema of the lung).

Treatment

In the rare cases where a cause is found, the treatment of the latter can involve the cure of the HTA sometimes (by withdrawing surgically a Adénome of Idiot for example).

The treatment rests on the comprehension of the physiopathological mechanisms of regulation of the blood-pressure.

The treatment of arterial hypertension aims to the standardization of the figures tensionnels, in order to prevent the complications of them. This prevention, by certain drugs, and on criteria of morbimortality, was proven by tests for thresholds of 160/95 mmHg (140/80 mmHg in the diabetics or after a avc). There does not exist proof to justify a treatment for lower thresholds.

Several means are at the disposal of the expert.

Hygiéno-dietetic rules (relating to the hygiene of life and the dietary habits)

They can sometimes be enough to standardize the blood-pressure and must always be proposed:

Weight loss, in the event of ponderal overload.
If necessary, removal of liquorice.
Reduction in the consumption of salt and alcohol:
1. To avoid the salt box on the table, the Saltings, the dishes cooked
2. to limit alcohol (2 glasses of Wine per day at the man, 1 glass at the woman).
Fight against the associated risk factors (tobacco, cholesterol, diabetes, sedentariness).
To use a pill slightly proportioned in estrogens.
At the neurotonic ones, to avoid the The, the Coffee; to associate relieving if required.
To carry out a calm and regular life if possible, by respecting the hours of sleep
Recommendation of the practice of physical exercises: a regular aerobic physical-activity (at least 30 minutes the every day).

Medicamentous treatment

The medicamentous treatment can be nonspecific (Analgésique for cephalgias, Sédatif at neurotonic…) or specific: they are the Antihypertenseur S.

It is given, essentially, with life. It must be, ideally, simple, effective and tolerated well. It must be naturally explained to the patient. The multiplicity of the drugs implies that none is perfect. The choice is made by the Médecin according to the type of hypertension, the associated diseases, the effectiveness and the tolerance of the various products. It is current that it is necessary successively to test several drugs before finding that which is appropriate to the treated patient.

In first intention (i.e., the patient not having never been treated), the doctor can choose a molecule with a conventional amount ( Monothérapie ) or two molecules with small amounts ( bithérapie ).

In the event of inefficiency (or of insufficient effectiveness), one can, either to continue a monothérapie with another Classe of drugs, or to make a bithérapie with full amount. It should be noted however that the first cause of inefficiency remains the irregular catch or the absence of catch of the drug prescribed (bad Observance).

If the HTA is severe, one can have to take three, even more, classes of different molecules.

Among the antihypertenseurs, one distinguishes:

The Diurétique S

They act by elimination, via the Urine, of part of the water and sodium contained in blood: this induces a reduction in blood volume and thus a fall of the blood-pressure. Example of diuretic: the Furosémide and the Amiloride. This last, although of less effectiveness, prevents the potassium loss, and is indicated in certain clinical pictures.

Beat-blockings

The Bêta-bloquant S act mainly by reducing the activity of the Catécholamine S on the Cœur and by decreasing the secretion of Rénine. They are particularly indicated in the event of associated ischemic cardiopathy.

At the hypertensive one, it is preferable to call upon the molecules known as selective (bisoprolol, nébivolol) which present less side effects.

It is necessary to respect the Contre-indication S (absolute at the hypertensive one): Asthma, turbid severe of conduction, Acrosyndrome (blue and painful fingers cold)

Inhibiters of the enzyme of conversion

The inhibiting of the enzyme of conversion (IECA, IEC) fight the stimulation of the system Rénine - Angiotensine - Aldostérone and reduce the circulating rates of angiotensin II and aldosterone. The IEC thus will reduce the vasoconstriction normally induced by angiotensin II as well as the réabsoption of the water normally caused by the action of the aldosterone on the kidney. They thus involve a vasodilatation as well as a reduction in the volemy. In addition, they prevent the degradation of the Bradykinine, substance vasodilatatrice. The inhibiters of the enzyme of conversion are all the more effective as the system renin-angiotensin-aldosterone is stimulated: strong falls of pressure can be thus observed in certain circumstances: Déplétion containing soda precondition (lack of sodium in blood), contracting of the renal artery.

Good performances are in particular obtained by using weak amounts of inhibiters of the enzyme of conversion, associated with a hyposodé mode, even with weak amounts of Diurétique (the latter increasing the sodium escape in the urines and thus stimulating the system renin-angiotensin-aldosterone).

The inhibiters of the enzyme of conversion are contra-indicated in the event of Grossesse and among patients consuming:

of potassium salts,
of the Immunosuppresseur S or
of the Lithium.

Antagonists of angiotensin II

The antagonists of the receivers of angiotensin II (ARA-II or Sartan S) are a relatively new therapeutic class which causes a great interest by its very good tolerance and an original mechanism of action (direct blocking of the receivers of the Angiotensine II). They have effects very close to those of the IEC (but without blocking of the degradation of the Bradykinine).

Calcic inhibiters

The calcic inhibiting reduce the tonicity of the arteries by decreasing the capacities vasoconstrictrices (calcium-dependant) of arterial smooth muscle fibers by inhibiting the transmembrane transfer Calcium.

Other antihypertenseurs

They are rather used as auxiliary treatment.

central antihypertenseurs
1. central alpha-stimulants: They decrease tonicity sympathetic nerve vasoconstrictor. Their undesirable effects limit their employment of it (dryness of the mouth, somnolence, orthostatic hypotension, nauseas…).
Alpha-blocking S peripherals
the Vasodilator S

“Recommendations”

Several learned societies published “recommendations” (or “guidelines” in English) on the assumption of responsibility of arterial hypertension. The American recommendations are with seventh version (JNC1 going back to 1976 until the JNC7 published in 2003).

The European Société of Cardiology published in June 2007 its own recommendations.

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