Aortic stenosis - a disease related to defects of the heart of the system.The word refers to an organic defect of damage to the structure of the heart valve or valve openings.The causes of these diseases are different, congenital abnormalities and to the consequences of infectious endocarditis.
peculiarity group of diseases, which include aortic stenosis, is the emergence of serious hemodynamic disturbances.Since normal blood flow is disturbed, the heart has to pump large volumes of blood to cope with a higher intracardiac pressure than if it had managed to deal with those in the standard.As a result, a number of injuries seen in the work of individual agencies.
also need to know that aortic stenosis is one important feature - it has an extremely slow its manifestation.This is due to the stronger muscular layer of the left ventricle.It is longer cope with the impact of high blood pressure that occurs when there aortic stenosis.
Under stenosis in medici
Localization damaged aortic valve stenosis is divided into subvalvular and valves.The most common type of aortic stenosis is, of course, acquired valvular aortic stenosis.As mentioned in the medical literature, the diagnosis of "aortic stenosis", the default is meant congenital valvular aortic stenosis.
Aortic stenosis causes
One of the most common causes of aortic stenosis is rheumatic fever.Under the influence of the pathogen rheumatism B hemolytic streptococcus, melts commissure (connective tissue bearing valves), then aortic valve spliced and fibrosis.After that, the wings are laid calcifications and the size of the aorta is narrowed considerably.As a result of developing aortic stenosis.
also to the appearance of aortic stenosis cause age-related changes: the emergence of calcium in the aortic valve, its subsequent fibrosis and impaired mobility.
It is also important to understand what triggers pathological processes in the heart of aortic stenosis.These processes are essential for the correct perception of the clinical picture of the scheme and purpose of treatment.
Normally, the size of the aortic orifice of an adult is approximately 4 cm. When aortic stenosis is a narrowing opening.As a result, the opening of the aorta has a much smaller area than normal.Reducing the area of the opening of the aorta results in complication of the passage of blood flow into the aorta from the left ventricle.To edit or delete this difficulty and not to violate the process of normal blood supply to the body, the heart is trying to increase the pressure in the chamber of the left ventricle.The pressure is increased at the time of systole, the left ventricle - the moment when the heartbeat blood spreads into the aorta.In addition, the heart that automatically lengthens systole.Thus, the heart of trying to "force" to squeeze blood through the narrowed mouth of the aorta, aortic stenosis, and increase the transit time of blood into the aorta.Heart starts these mechanisms with a single purpose - to ensure the normal ejection of blood in the aorta.
impact of increased pressure in the chamber of the left ventricle does not remain unpunished for the heart.In response to the increase in systolic pressure appears hypertrophy muscular layer (infarction) of the left ventricle.It develops to the myocardium to cope with a high pressure gradient and to provide it with the release of this blood volume, which may well perfused organs in need of it.But the increased muscle mass of the left ventricle is much worse relaxes and stretches.Because of this, during diastole (relaxation of the left ventricle) is rapidly increasing diastolic pressure.
Normally, the heart performs the following cycle:
1. atrial systole: thanks to muscle contraction pushes blood into the ventricles.Then, relax atrium, and their diastolic pressure occurs.
2. ventricular systole.During ventricular contraction, blood flow is in the pulmonary veins from the right ventricle and in the aorta from the left.And then he rushes into the systemic circulation.
3. Total diastole.
important to understand that when one of the heart one phase of the cardiac cycle, in another department takes quite the opposite.Thus, when the atrial systole, the ventricular diastolic pressure is that point.
Thus, the high pressure chamber of the left ventricle at the moment of relaxation will disrupt the process which is the left atrium pushing blood flow into the chamber of the left ventricle.In simple terms, the left atrium is not emptied completely, and there will be a certain amount of blood.Therefore, the left atrium increases the number of its cuts to it had no "excess blood."
But, despite the fact that the left ventricular myocardium is strong enough, even he can not cope with the ever-increasing pressure.At some point the ventricle ceases to resist the pressure and dilatiruetsya (stretched) under its influence.The stretched ventricle pressure continues to grow and already affects the left atrium.Unable to cope with a high diastolic pressure in the ventricle chamber being congested, and atrial stretch.High blood pressure affects the left atrium pulmonary veins and there is such a thing as pulmonary hypertension.
as a result of aortic stenosis leads to the following pathological conditions:
1.Rastyanuty left ventricle can no longer dispose of the normal volume of blood, and therefore, can develop impairment of left ventricular function.
2. As a result of the prolonged existence of aortic stenosis, which is not accompanied by any compensatory processes may be affected by the right heart.As a result of growing pressure in the left ventricle at first, then in the left atrium and its consequent impact on the pulmonary veins develop mitral - aortic stenosis.It will be characterized by the presence of aortic stenosis and mitral valve insufficiency, which will be due to the extension of the right heart.
believed that the time in which the left ventricle myocardium stops to cope with high systolic blood pressure, and finally stretched, causing the subsequent characteristic change of aortic stenosis, an average of 4 years.
By the way, in the clinic of aortic stenosis is the so-called concept of "critical stenosis."This reduction in the opening of the aortic valve to 0.75 cm 2. In this embodiment, the aortic stenosis patient rapidly develop pulmonary edema and heart failure.
And if the opening of the aortic valve will have an area of 1.2 cm to 0.75 cm, this would be called a moderate stenosis of the aortic stenosis.
Accordingly, narrowing of the aortic valve orifice area within the range of 2.0 to 1.2 cm, and then this will be called stenosis negligible.
Aortic stenosis symptoms
As described above, generally for a long time, patients do not complain of symptoms of aortic stenosis.For a long time it is in the stage of compensation.Complaints of patients to any discomfort occur when the opening of the aortic valve is already destined by almost half.
first "calls" the possible presence of aortic stenosis are syncope, or fainting.Their expression is explained by the following mechanism that accompanies aortic stenosis.The fact is that when aortic stenosis occurs mechanism "fixed ejection."It lies in the fact that during exercise the heart can not increase cardiac output due to narrowing of the aortic valve opening.Due to the lack of adequate blood supply during exercise in patients with aortic stenosis appears dizziness, nausea, weakness.When later the degree of stenosis can occur even temporary loss of consciousness.
also signs of aortic stenosis can occur in ischemic cardiac pain.This clinical manifestation is due to the fact that the aortic valve cusps begin the coronary arteries, which are included in the blood supply to the heart.Due to the level of a violation of the normal pressure between the left ventricle and the aorta mouth, there is a reduction of blood flow in the artery.As a result, blood flow to the heart is insufficient, and thus will appear myocardial ischemia and its clinical manifestations - heartaches.
Third subjective complaints when aortic stenosis is shortness of breath.Emerging as a result of dysfunction of the left ventricle, first in diastole, and later in systole, shortness of breath may turn into a left ventricular failure.It will manifest cough with abundant pinkish frothy sputum.That frothy sputum with a pinkish color - a bright sign of stagnation in the pulmonary circulation.Pink at the sputum is due to a slight shift of the red blood cells of the pulmonary arteries in the alveoli, which are surrounded by dense pulmonary vessels.
But finally confirm the diagnosis of aortic stenosis is possible only with the full examination of the patient.The only way to identify a number of symptoms characteristic of aortic stenosis.
first of all pay attention to the appearance.When aortic stenosis will be marked pallor of the skin.This is because that same impaired and reduced left ventricular ejection.
Since the left ventricle at the aortic stenosis got even higher muscle mass and decreasing rapidly, do not be difficult to identify a strong apical impulse and characteristic tremors throughout the atrial area.Most often it is a concussion goes into resonance with the heartbeat.
If we apply the hand in the second intercostal space on the right okologrudinnoy line (this is the point where the aorta is usually dried), you can feel the trembling fingertips, which will appear at the time of contraction of the left ventricle.This jitter is the result of blood flow through the narrowed mouth of the aorta.And the more narrowed aorta, the brighter the better it will be determined by shaking or "purr".
If you start a study pulse, the patient with aortic stenosis it is rare, a small filling.Rarer are explained thereby reducing second compensatory mechanism that will trigger the heart - increased frequency of contractions of the left ventricle.
And if you examine the blood pressure and the presence of aortic stenosis will speak reduced compared with normal systolic ("upper") pressure.
But, undoubtedly, the most faithful clinical signs of aortic stenosis is a definite pattern that the doctor listen using Phonendoscopes.
Drying sign of stenosis of the aortic valve aortic systolic you can easily find, rude noise.The reason for its occurrence is the same as that of the "jitter", which has already been described above.The blood goes through the narrowed part of the aorta, having its "twist" and noise.As jitter, this phenomenon occurs at the time of contraction of the left ventricle (i.e., its systole).
In addition, there are other interesting changes in the valvular that can hear.Since the systemic circulation is sent to a fairly small amount of blood, 2nd tone (and he is tone-diastolic left ventricle, and is obtained by the collapse of the three aortic valve) is much weaker than normal.A small amount of blood slams the aortic valve with a small force.Sometimes the 2nd tone even be difficult to hear.The reason for this is simple: when the aortic valve stenosis often fibrozirovany, and therefore inactive and again slam with much less power and sound.
While in the chamber of the left ventricular diastolic pressure began to increase, the 1st tone (tone purity) will be relatively normal sound.However, since the duration of systole of the left ventricle is enlarged, the doctor with an ear for music will be able to listen to a small reduction in systolic sonority tone.
Furthermore, when the decompensation occurs, and the pressure during diastole increases - in the field of cardiac apex appears 3rd and 4th tones.These tones do not show up during the normal functioning of the cardiac valvular apparatus, and therefore, are considered to be pathological.These tones will tell the doctor that has involved the left atrium, and it is struggling to push through the blood into the left ventricle, where it interferes with high diastolic pressure.
When running the clinical symptoms of the disease process beyond the heart and are located in those organs, blood supply which is subject to violation, though one or another prophet.When aortic stenosis mostly affects the lungs.If they listen to Phonendoscopes, you can hear the wet wheeze bubble - a sign of the presence of fluid in the lungs.Also, tapping light, in the presence of liquid in them, you can hear the percussion sound is shorter and less ringing.
Aortic stenosis treatment
Treatment of aortic stenosis include surgical and conservative methods.The conservative methods of focus given to remedy the violation of blood flow, cardiac arrhythmias and prevention of infective endocarditis.
first try to eliminate the phenomenon of stagnation in the pulmonary circulation.Assign diuretics (often use Furosemide).It is important to appoint them, taking into account all the clinical, instrumental and subjective data and used with great caution.
When atrial fibrillation is prescribed cardiac glycosides (digoxin).
also quite widespread in the treatment of aortic stenosis received drugs potassium.
to improve myocardial relaxation of hypertrophied use of B-blockers, calcium blockers or antagonists (particularly those that relate to a number of verapamil).
Application group of nitrates in aortic stenosis is contraindicated.Nitrates reduce cardiac output and minute volume of blood.This could easily lead to lower blood pressure to a critical level.
The most common conservative therapies combined with surgery: they are used in the preoperative patient and the postoperative period.
But the main method of treatment of aortic stenosis are surgical treatments.They depend on the degree of decompensation blemish various violations that were the result of vice and present contraindications.
The most common prosthetic aortic valve balloon or plastic valve.
main indications for surgical correction of aortic stenosis are:
1. Have a satisfactory function of the myocardium.
2. If the systolic pressure gradient in the region of the aortic valve is higher than 60 mm Hg.Art.
3. On the ECG, there are signs of increasing left ventricular hypertrophy.
In turn, the main contraindications to surgery are:
1. The pressure gradient across the valve of the aorta above 150 mm from the station.
2. Severe degenerative changes of left ventricular myocardium.
Aortic stenosis surgery
One of the most commonly used surgical interventions is the artificial aortic valve replacement.If, however, in the leaflet when aortic stenosis revealed minor changes, it is more appropriate to confine less bulky surgery: surgical separation spliced leaflets of the aortic valve.
operation on artificial tricuspid aortic valve replacement is performed after connecting the patient to the heart-lung machine.