Aortic valve stenosis: what it is, how to treat it, and is it worth it to be afraid

What is aortic stenosis?

Aortic stenosis (AS) is a narrowing of the area of the outflow tract of the left ventricle (the place where the aorta exits the heart) caused by calcification of the valve leaflets or its congenital anomalies, which create a barrier to the expulsion of blood into the vessel.

An isolated variant of aortic valve stenosis is an extremely rare case (no more than 4% of the total), mainly AS is combined with other heart defects. More often this is an acquired condition due to destructive processes in the tissues of the valve; less often - a congenital anomaly of the structure.

According to the level of narrowing of the mouth of the aorta, they are distinguished: valvular, subvalvular and supravalvular stenosis. The most common is valve stenosis itself (fibrosed leaflets are welded together, flattened and deformed).

Stenosis of the left ventricular outflow tract (LV) creates a barrier to blood flow and creates high pressure on the aortic valve during LV systole. To maintain proper blood volume, the body increases the heart rate, shortens diastole (myocardial relaxation period), and lengthens the expulsion time of blood from the LV. Due to insufficient emptying of the LV, the end-diastolic intraventricular pressure rises. As a result, LV myocardial hypertrophy develops according to the concentric type (thickening of its muscle layer mainly in the area of the aortic valve).

The compensatory capabilities of the heart are capable of maintaining sufficient hemodynamics for a long time. A hypertrophied organ in the advanced stages of aortic stenosis can increase to an enormous size. Gradually, hypertrophy is replaced by LV dilatation and circulatory decompensation. The breakdown of compensatory mechanisms is facilitated by the development of chronic insufficiency of the coronary vessels (an enlarged myocardium requires more blood supply). The result of the above processes is development:

LV failure;
passive hypertension of the small circle;
stagnation in the systemic circulation.

The normal area of the AK hole is 3-4 cm²... Symptoms of hemodynamic disorders develop with a narrowing of the AK area to ¼ of the original normal value.

Symptoms of aortic stenosis

AS in adults has no manifestations for a long time. Symptoms may be absent up to 20-30 years from the onset of the disease. Possible patient complaints include:

fatigue, shortness of breath on exertion, decreased ability to work;
dizziness, fainting;
pain in the pericardial region, palpitations;
abdominal pain, nosebleeds.

Objectively, the doctor can determine:

pulse: low filling, plateau;
tendency to bradycardia and arterial hypotension;
on palpation: a slowly rising, high, resistant apical impulse, which is displaced to the left and down;

Auscultatory signs

Auscultation data are of great diagnostic value:

Rough systolic murmur with a projection into the second intercostal space at the edge of the sternum on the right, which is well carried out in the area of the jugular notch, on the carotid arteries, the apex of the heart. This is a mid-frequency ejection noise that appears at the end of the I tone.
Aortic valve opening click what is listening to an additional tone during systole, arises after the I tone, is best heard at the left edge of the sternum;
Paradoxical bifurcation of the II tone;
Listening to the IV tone.

On the ECG, severe hypertrophy and LV overload are determined (depression of the ST segment, deep inversion of T waves in the left chest leads and aVL), an increase in the QRS amplitude, blockade of LPH, AV block of various degrees.

On Ro-graphy of the OCP, the changes become noticeable in the case of advanced AK stenosis. There is a rounding of the hypertrophied apex, dilatation of the ascending part of the aorta distal to the stenosis, and calcification of the AK.

AC criteria according to echocardiography are:

an increase in the wall thickness of the LV and IVS;
The valves of the AK are inactive, thickened, fibrosed;
High transvalvular pressure gradient according to Doppler echocardiography.

Classification and degree of manifestation of pathology

Narrowing of the outflow tract can form at various levels:

The aortic valve itself;
Congenital deformed bivalve AK;
Subvalvular stenosis;
Fibrous or muscular subaortic stenosis (valve-subvalvular);
Supravalvular stenosis.

Classification of aortic stenosis by severity:

Grade I - moderate stenosis (full compensation). Signs of AS are detected only on physical examination;
II degree - severe stenosis (latent heart failure) - there are nonspecific complaints (fatigue, syncope, decreased exercise tolerance); the diagnosis is verified according to the data of EchoCG, ECG;
III degree - sharp stenosis (relative coronary insufficiency) - symptoms are similar to angina pectoris, signs of blood flow decompensation appear;
IV degree - critical stenosis (pronounced decompensation) - orthopic, congestion in both circles of blood circulation;

Gradient classification

Severity	AK hole area (cm2)	Average transvalvular pressure gradient (mm Hg)
Norm	2,0-4,0	0
Mild stenosis	≥ 1,5	0-20
Moderate stenosis	1,0-1,5	20-40
Severe stenosis	≤1	40-50
Critical stenosis	Less than 0.7	>50

Special types of aortic stenosis

In addition to the valve stenosis itself, there are narrowings of the outflow tract of congenital etiology or without primary damage to the AV bundles.

Subvalvular aortic stenosis

Subaortic stenosis is a narrowing in the LV outflow tract distal to the valvular ring in the form of an intermittent membranous diaphragm or fibrous membrane. The development of this type of AS is facilitated by congenital structural features of the LV excretory tract, but clinical manifestations of the disease do not occur at an early age.

There are three main anatomical types of subaortic stenosis:

Membranous-diaphragmatic - discrete subaortic membrane;
Fibrous-muscular collar (roller) - with asymmetric IVS hypertrophy;
Fibromuscular tunnel - diffuse subvalvular stenosis.

Also, various abnormalities of the mitral valve, VSD, can lead to subvalvular stenosis.

Turbulent blood flow causes secondary damage to AK, which aggravates the phenomenon of stenosis and leads to the development of aortic insufficiency. Due to the relative coronary insufficiency in patients, areas of subendocardial ischemia are formed, followed by myocardiofibrosis. The leading cause of death is fatal arrhythmias and myocardial infarction.

The clinical features of this type of defect are: early onset of symptoms, frequent fainting, on auscultation there is no click of the opening of the AK during systole at the apex of the heart, soft diastolic murmur.

Supravalvular aortic stenosis

Supravalvular stenosis is a narrowing of the lumen of the ascending aorta (local or diffuse) in the sinotubular region. The stenotic process involves the aorta, brachiocephalic, abdominal and pulmonary vessels.

According to the etiology, the forms are divided:

Sporadic (consequences of intrauterine rubella infection);
Hereditary (autosomal dominant type);
Williams syndrome (combined with mental retardation).

In this type of AS, the coronary vessels are located proximal to the stenosis and are under the influence of high pressure, therefore they are dilated, twisted and susceptible to the development of early arteriosclerosis.

The clinical manifestations of AS are combined with multiple organ abnormalities, impaired metabolism of vitamin D, hypercalcemia, anginal attacks are more common, there is a difference in blood pressure in the arms.

What is Critical Aortic Stenosis?

The term "critical aortic stenosis" is used in the context of:

Severe stenosis that manifests itself during the first months of life;
LV dysfunction or critical decrease in CO (cardiac output);
The possibilities of systemic blood flow are exclusively with an open Botallic duct.

The presence of a critical narrowing of the left ventricular outflow tract is a direct indication for emergency surgery.

This definition is used in pediatrics in relation to newborns with extremely low CO and decompensated circulatory failure. Symptoms of critical stenosis are similar to those of hypoplasia of the left heart. The life of such children is determined by the functioning of the Botallic duct, early use of prostaglandins E₁ and carrying out emergency surgery.

The mortality rate from this pathology is about 86% (even taking into account surgical treatment).

Aortic stenosis in newborns and children

In children, AS is combined with other vices:

Two-leaf or single-leaf configuration AK;
Coarctation of the aorta;
Open Botalovy duct;
VSD;
Mitral insufficiency;
Fibroelastosis of the left ventricular endocardium;
WPW syndrome;

AS is found 2-4 times more often in boys and is often combined with connective tissue diseases.

As the child grows older, stenosis is aggravated due to the growth of the heart muscle and the progression of fibrosclerotic changes on the valve.

Surgical correction is performed when the transvalvular gradient is> 50 mm Hg.

Disease treatment methods

All patients with AK stenosis, even without clinical manifestations, are recommended:

Limitation of physical activity;
Prevention of infective endocarditis - deformed valves become an "easy target" for bacterial infection;
Continuous dispensary observation;
Symptomatic therapy.

Is it possible to medicate the narrowing of the aorta?

The role of drug therapy in the treatment of AS is relatively small. Conservative treatment can reduce the symptoms of heart failure, improve hemodynamics somewhat.

List of drugs used:

Cardiac glycosides - preferably Korglikon, Strofantin, Celanide;
Diuretics - Veroshpiron, Hypothiazide (decrease the minute volume of the heart)
Peripheral vasodilators - Hydralazine, ACE inhibitors (under the control of blood pressure);
β-blockers, Ca antagonists²⁺ (with angina pectoris, compensated stenosis);
Anticoagulants - in the presence of thromboembolic complications;
Class III antiarrhythmic drugs - Amiodarone (for atrial and ventricular arrhythmias).

Features of surgical correction of pathology

The choice of the method of invasive correction depends on the clinical condition of the patient, his age and the form of the defect. Contraindications for surgery are stages I and IV of AK stenosis.

Types of surgical interventions:

Percutaneous aortic balloon valvuloplasty is an endovascular method performed in infants with critical stenosis or in pregnant women;
Aortic valvotomy - used in children, performed on an open heart;
Prosthetics of AK - carried out with congenital anomalies of the structure of the AK (single leaf, dysplastic bivalve) or in patients after valvotomy with progression of stenosis.
A mechanical prosthesis, porcine bioprosthesis, aortic alograft, pulmonary valve autograft are used;
Autotransplantation of the pulmonary trunk with a valve into the aortic position and reconstruction of the outflow tract of the pancreas with a homograft (Ross operation) - indicated for children 1 year of age;
Dilation of the aortic root with valve replacement (Konno's operation) - indicated for severe stenosis or tunnel-shaped obstruction.

Conclusions

For aortic stenosis, an asymptomatic course is characteristic, but after the onset of clinical signs of defect decompensation without invasive treatment, patients die within several years (in 50% of cases, death occurs after the first 2 years). The ten-year survival rate after AV prosthetics is 60-65%, the life of the artificial valve is 10-15 years. All patients who underwent invasive interventions on AK are monitored by a cardiologist for life. Also, such patients must carry out antibiotic prophylaxis of endocarditis before any surgical intervention.