Pulmonary artery stenosis( SLA) in newborn infants is a narrowing of the lumen of the outflow tract of the right ventricle. Pathological changes affect the pulmonary artery valve or part of the vessel in the valve area.
According to statistics, the different forms of isolated ALS account for about 10% of cases of congenital heart diseases. Most often, valve stenosis, often associated with congenital heart defects, is revealed.
Causes of
The etiology of congenital heart disease is not yet fully understood. The causes of the development of congenital heart diseases, including ALS, can be :
- Weighed heredity. The risk of having a baby with a congenital ALS is higher if any of the parents, close relatives or other children in the family have a diagnosis of heart disease.
- The presence of systemic or metabolic diseases in the mother.
- Infectious diseases, suffered by the mother in the early stages of pregnancy, in particular, viral.
- Some medications with side effects of teratogenic effects.
- First birth at the age of more than 38 years.
- Multiple pregnancy.
- Extracardial fetal abnormalities.
- Chromosomal diseases.
- Disturbances of fetoplacental blood flow.
- Fetal heart rhythm disturbances, including episodic.
Classification
Depending on the localization of the vessel's narrowing, is allocated to the supra-valvular, valvular, subvalved pulmonary artery stenosis in a newborn child. In cases of combination of two types of ALS or pulmonary artery stenosis with other pathologies of the heart, the form of the disease is defined as combined.
Valve form of the pathology is diagnosed in approximately 90% of patients. The valve of the pulmonary artery in patients with valvular pathology may have an abnormal structure( single- or double-leaf valves).A characteristic anatomical feature of pathology is the poststenotic enlargement of the arterial trunk.
The characteristic anatomical feature of subvalvular stenosis is a funnel-shaped narrowing of the vessel or an abnormal arrangement of the muscle bundle that hinders the release of blood into the pulmonary circulation. Isolated subvalvular stenosis of the pulmonary artery is often accompanied by a defect of the interventricular septum in the newborn.
Supraventricular stenosis is often found against the background of Williams and Noman syndromes. This pathology occurs in the form of multiple peripheral narrowing, membrane, localized narrowing or diffuse hypoplasia.
The dimensions of the right ventricle and tricuspid valve in patients with ALS are usually within the normal range. The narrowing of the lumen of the pulmonary artery complicates the blood flow, as a result of which the increases the pressure gradient between the right ventricle and the pulmonary circulation of the .The pathological structure of the vesting tract is the cause of systolic overloads of the myocardium.
The manifestations of ALS depend on the severity of the narrowing .With a minimal pathology, accompanied by a pressure gradient up to 40 mm Hg. The disease can be asymptomatic. The average degree of stenosis is determined with a pressure difference of 40-70 mm Hg. It is accompanied by increased fatigue and shortness of breath during physical exertion.
With a pressure gradient in excess of 70 mm Hg. Art.speak about critical stenosis. Against the backdrop of the critical form of , the disease in newborns shows symptoms of heart failure, as well as cyanotic skin caused by right-left blood discharge through the oval window.
What are the manifestations of Eisenmenger syndrome and what can it develop from? All the details are in a separate article. Find out in what cases when a stenosis may occur aortic valve failure, from this material.
On the features of the congenital defect of the Ebstein abnormality, read in another publication.
Symptoms of
The mild form of the inborn ASL may not last long enough .Indirect indication of the possible presence of pulmonary circulation pathologies in infants can be a backlog in physical development, frequent colds with complications in the form of pneumonia.
The most characteristic symptom of the average and critical stenosis is the cyanotic color of the nasolabial triangle, lips and nail holes .The critical stage of the pathology is accompanied by symptoms of progressive right ventricular heart failure. With physical exertion, dyspnea develops.
Percussion allows the to detect the displacement of the heart boundaries to the right .When listening to cardiac tones, a characteristic rough noise is heard during systole, the intensity of which is proportional to the degree of narrowing of the vessel. II tone above the pulmonary artery is strongly attenuated or absent. Above the projection area of the valves, the second tone is bifurcated, and the ejection noise can be listened.
Diagnostics
To confirm the preliminary diagnosis based on the general inspection data, the requires an instrumental examination of the .Usually in practice they apply:
- X-ray examination;
- ECG;
- Echocardiography;
- Doppler.
The x-ray shows the narrowing of the pulmonary artery mouth and the extended heart boundaries of the .The image of the lungs is often depleted.
With minor stenosis, the patient's electrocardiogram can be normal, , in more severe forms of the pathology, the characteristic changes of manifest, pointing to:
- Hypertrophy of the right ventricle;
- Hypertrophy of the atrial septum.
In some newborn patients with a critical stenosis , ECG shows evidence of right ventricular hypertrophy .This effect is explained by its large size against the background of the hypoplastic left ventricle.
The echocardiographic examination of makes it possible to detect abnormal expansion of the pulmonary artery trunk in the area immediately behind the narrowing site, narrow arterial branches, pathological structure of the valve, hypertrophic changes in the right ventricular myocardium and some other pathological features of the heart anatomy.
The echocardiogram also identifies the changes in the pressure gradient between the right ventricle and the pulmonary circulatory system, corresponding to the clinical picture of pathology of moderate and critical severity.
In some cases, Doppler is used to assess the difference in pressure in the ventricle and arterial bed.
Treatment of
The only effective way to treat ALS is surgical intervention - elimination of narrowing of .The operation is indicated for patients with an average and critical ALS.Minimal narrowing of the vessel does not require surgical intervention and in some cases can go away spontaneously.
The type of operation is selected depending on the degree of severity of the patient's condition. In severe cases, the operation is performed by in the first months of life. The average degree of stenosis undergoes a surgical correction after the patient reaches the age of 5-10 years .
With isolated valve ALS, various variations of valvuloplasty have proven successful.
In most cases, is performed by the endovascular balloon valvuloplasty .The essence of the method consists in introducing into the stenotic area of the inflatable balloon into which air is injected through the catheter. The expanding balloon mechanically extends the narrowed section.
is a less common open valvuloplasty, in which the surgeon dissects the fused commissures. Usually, an open procedure is performed when the balloon valvuloplasty is ineffective. Sometimes patients with a critical stage of pathology are given balloon atriosepthomy. Some forms of ALS require surgical correction in the form of systemic-pulmonary shunting.
In the case of supraplavened stenosis in the narrowing region, is reconstructed using a patch from the patient's own tissue or by installing a xenopericardial prosthesis. The tactic of treatment of subvalvular stenosis involves the removal of the narrowed section of the artery.
Prognosis and prevention measures
Among the most important preventive measures for are the provision of conditions for the normal course of pregnancy .Future mothers who are at risk should follow the doctor's recommendations with particular care.
Modern diagnostic methods allow to detect violations of the formation of the fetal cardiovascular system, which makes it possible to prescribe treatment aimed at eliminating the disease that is their cause.
The minimal contraction of the pulmonary artery in newborns for duration and quality of life is not affected by .Patients with identified abnormalities are recommended to observe the cardiologist and cardiac surgeon, as well as the prevention of infective endocarditis.
