Coarctation of the aorta
Coarctation of the aorta is a violation of the normal development of the aortic vessel in the form of a local intraluminal narrowing of the aortic arch in the projection of its isthmus until complete interruption. This congenital pathology should not be attributed to true heart defects, since the localization of constriction may be located in remote areas (thoracic and abdominal parts). Congenital coarctation of the aorta under any conditions is not accompanied by the development of organic damage to the heart, but this pathology inevitably provokes the development of damage to the structures of the cardiovascular system as a whole.
In the general structure of the incidence of congenital heart disease anomalies, coarctation of the aorta is 15%, and there is a clear correlation between the risk of this pathology and gender (predominance of male patients).
The combination of coarctation of the aorta with the opening of the arterial duct, the intraluminal diameter of which exceeds the diameter of the aorta, is observed mainly in the infants and is about 60%. A characteristic pathological change in the aorta below the site of constriction is an aneurysmal luminal widening, which arises as a result of the development of a vortex blood flow. When the patient has an aortic lengthening and its tortuosity, provided there is no true intraluminal narrowing, the term "pseudo-cortex of the aorta" should be used.
Causes of coarctation of the aorta
The development of coarctation of the aorta, as well as of any other congenital anomaly, is based on the disturbance of the process of normal aortic wall formation even in the perinatal period. The main mechanism for the formation of stenotic constriction of the aorta is the excessive proliferation of tissue elements from the arterial duct to the auktuctal auklet during the period when the arterial duct closes, which normally has a lumen only before the birth of the child. Such a pathogenetic mechanism of development has coarctation of the aorta in newborns, and in the "adult version" stenotic aortic constriction develops with massive atherosclerotic lesion, traumatization of the vascular wall and Takayasu's syndrome , in which aortic lesion is inflammatory.
Risk factors for the development of coarctation of the aorta of an innate character are fetal infectious damage in the prenatal period, alcohol abuse during pregnancy, and, to a greater extent, genetic heredity.
There is some correlation dependence of the development of congenital coarctation of the aorta among children suffering from some genetically determined anomalies ( Shereshevsky-Turner syndrome ).
Hemodynamic disturbances in coarctation of the aorta may have a different degree of severity, which predetermines the intensity of clinical manifestations, however, the pathogenetic mechanism of cardiohemodynamics disorders in all pathomorphological variants is unified. Thus, in the projection of the aneurysmically enlarged aorta, which is located above the projection site of the narrowed section, a vortex blood flow with a high pressure gradient is formed, which explains the hypertrophy of the muscular massif of the left ventricle of the heart. Below the narrowing of the aortic lumen, on the contrary, low blood pressure is observed, so compensatory mechanisms are launched in the form of collateral blood supply networks.
Due to the fact that coarctation of the aorta that occurs in an adult is not accompanied by the opening of the ductus arteriosus, in this category of patients there is an increase in systemic arterial pressure due to the systolic and diastolic component, exclusively in the upper half of the trunk. To improve blood circulation in the arterial network of the lower half of the trunk, the compensatory mechanism of renal arterial pressure that worsens the course of the underlying disease is triggered.
Symptoms of coarctation of the aorta
Adult patients with a secondary variant of coarctation of the aorta, in most cases, note the presence of nonspecific clinical symptoms in the form of headaches, dizziness , infrequent episodes of low-intensity nasal bleeding, increasing weakness. Symptoms related to the group of specific signs of coarctation of the aorta include progressive muscle weakness and frequent convulsions in the lower limbs, chilliness of the distal sections of the lower limbs. A prolonged course of hemodynamic disturbances with coarctation of the aorta provokes the development of trophic disturbances in the muscular mass of the lower half of the trunk, which is why a disproportional physique is formed in the patient.
The formation of a clinical symptom complex with coarctation of the aorta directly depends on the age of the patient, the pathomorphological variant of the defect, and the presence or absence of the presence of other anomalies in the development of the structures of the cardiovascular system. Patients of the adult category most often do not present any characteristic complaints that allow them to assume the formation of coarctation of the aorta, in this connection, the methods of objective examination of the patient are more informative in this situation. Thus, the detection of a combination of a weakly filled pulse in the projection of the femoral arteries with a strained pulse on the arteries of the upper limbs makes it possible to establish a preliminary diagnosis at the stage of the initial examination of the patient.
At the late stage of the disease, a patient suffering from coarctation of the aorta complicated by heart failure has an extension of the boundaries of absolute dullness, as well as an increase and displacement of the apical impulse. Auscultatory signs of coarctation of the aorta is to listen to severe systolic noise at all points of auscultation with a maximum in the anterior axillary line. Difference of coarctation of the aorta, combined with non-closure of the arterial duct, is auscultation of systolic-diastolic heart noise in the projection of the second intercostal space along the parasternal line to the left.
In the era of rapid development of diagnostic instrumental imaging methods, the first step in establishing the correct precise diagnosis is not the data of objective examination of the patient, but the indicators of additional study of the structures of the cardiovascular system. Diagnosis of coarctation of the aorta should be carried out in the conditions of a specialized cardiosurgical hospital, since some imaging techniques refer to minimally invasive surgical interventions. Electrocardiography and phonocardiography do not allow to establish reliably the presence of coarctation of the aorta, however, in severe heart failure, the patients have signs of heart damage in the form of displacement of the electric axis, as well as signs of hypertrophic cardiomyopathy.
When conducting echocardioscopy, the main diagnostic criterion for coarctation of the aorta is the detection of dopplerographic curve violations in the projection of stenotic constriction of the aortic isthmus, as well as the detection of a vortex flow in the poststenotic aortic department. The most accurate and informative is contrast angiography, which is carried out to all patients, regardless of subsequent treatment. This technique allows you to clarify the exact location of stenosis, the severity and length of violations.
Coarctation of the aorta in children
The principal difference of the "child variant" of coarctation of the aorta from the "adult" is that in newborns the hypoplasia of the descending aorta is not accompanied by the closure of the arterial duct. This congenital malformation can be observed both in an isolated variant and in combination with other developmental defects of the cardial profile (atrial or interventricular septal defect, cardiac sinus aneurysm, transposition of the main vessels).
Coarctation of the aorta in children in most cases is a genetically determined pathology, so families with a history of pregnancy need to undergo medical and genetic counseling as a preventive measure during pregnancy planning.
Hemodynamic disturbances in this cardiac defect in children are not so much expressed, and this fact is explained by the combination of this anomaly with the opening of the ductus arteriosus; therefore, in this category of patients there is no sharp increase in the gradient of intraluminal pressure in the circulatory system of the circulatory system, and there are no signs of formation of a collateral type blood flow. In a situation where the child has a post-ductal variant of coarctation of the aorta, favorable conditions are created for the development of signs of pulmonary hypertension caused by a massive discharge of a large volume of blood with a high pressure gradient into the pulmonary artery from the aorta.
Early development of signs of heart failure in children with an inborn variant of coarctation of the aorta is due to the fact that even in the period of prenatal development the child develops a severe lesion of the myocardial membrane of the heart in the form of severe hypertrophy, both right and left parts of the heart. The negative fact is that simultaneously with the expressed hypertrophic changes of the myocardium there is no increase in the vascularization of the myocardium, therefore, in the early period the hypoxic lesion of not only heart structures but also of all tissues and organs occurs in the child. This pathogenetic mechanism provokes the development of fibroelastosis of the myocardium, which has an extremely negative effect on the course of the underlying disease.
The pre-vertex variant of the localization of coarctation of the aorta, which occurs in childhood, in most cases negatively affects the pulmonary circulation, since a large volume of blood flows from the pulmonary trunk into the descending aorta through the open arterial duct. This variant of cardiohemodynamic disorders has a very negative impact on the child's health and provokes early signs of heart failure.
The earliest clinical manifestations of coarctation of the aorta, especially of the preductal type, is the lightning-fast growth of the pulmonary insufficiency clinic, manifested by severe respiratory disorders, as well as objective visual signs of circulatory failure in the pulmonary vascular system (pronounced pallor until cyanosis , progressive inspiratory dyspnea). In infancy, children suffering from coarctation of the aorta tend to develop recurrent pneumonia of a stagnant type, characterized by prolonged course and severe respiratory failure.
The main clinical sign that allows to correctly establish the diagnosis of a "pre-oral version of coarctation of the aorta" in older children is the combination of unchanged skin in the projection of the upper extremities with pronounced diffuse cyanosis of the lower limbs. In addition, patients in this category have a critical increase in blood pressure parameters on the hands, reaching values of 200/100 mm Hg. If coarctation of the aorta in a child is combined with any other anomaly of the development of the heart, then for a long time the indices of blood pressure remain unchanged.
The main clinical criteria that testify to the decompensation of hemodynamic disturbances in coarctation of the aorta in children are: the emergence of an intense pain syndrome behind the sternum, complete absence of a pulse in the projection of the localization of the arteries of the lower limbs, frequent episodes of epistaxis, increasing respiratory disorders, as well as severe convulsive syndrome in the lower extremities.
Despite the fact that surgical treatment of aortic coarctation in childhood is the most effective method of eliminating the defect, there are absolute contraindications to the use of any types of surgical correction, which include - terminal heart failure, irreversible pulmonary hypertension, and also any chronic pathology in stage of decompensation.
Treatment of coarctation of the aorta
In the case of a congenital coarctation of aorta in patients of the children's age category, it is expedient to decide the question of conducting an operative intervention even during the period of prenatal diagnosis, as coarctation of the aorta provokes the development of severe cardiovascular insufficiency, aggravating the course of the underlying disease.
The indication for early surgical treatment is also the fact that in children in the first months of the antenatal period the mechanism of collateral circulation does not develop. In a situation where coarctation of the aorta is not accompanied by severe cardiohemodynamic disorders, surgical treatment should be postponed until the age of fourteen to prevent recoarction. Absolute indication for the use of emergency surgical treatment is the detection in the patient of the difference in the systolic component of intravascular blood pressure on the upper and lower limbs exceeding the level of 50 mm Hg.
Despite the fact that the only method of radical treatment of coarctation of the aorta, as well as of other cardiac defects, is the provision of an operational aid, an adequate preoperative preparation of the patient, implying the elimination of severe hemodynamic disorders, is a prerequisite. For the purpose of opening the arterial duct to newborn children who are subject to further surgical treatment, the use of Prostaglandin E at a calculated dose of 0.1 μg per kg of child weight is indicated. For the relief of signs of cardiopulmonary insufficiency, the use of drugs with an inotropic effect of short courses (Dobutamine at a calculated dose of 0.5 μg / kg / min) and an adequate oxygen therapy scheme for the correction of respiratory disorders is indicated.
Among the adult category of patients, the main criteria that testify to the necessity and expediency of using operative treatment for aortic coarctation are: a narrowed aorta of a large extent, the presence of concomitant signs of aneurysmal aortic lesion, as well as the decompensation of hemodynamic disorders, confirmed by instrumental methods of diagnosis. As an operational aid in this situation, endoprosthetics of the aorta with the use of a synthetic prosthesis are most often used.
Coarctation of the aorta
All types of surgical treatment of the defect are reduced to the fact that resection of coarctation of the aorta with subsequent plastic surgery of the wound defect is performed. At present, the question of the scope and methods of surgical correction of the defect is solved individually, taking into account the localization, the extent of the changes, and also the individual characteristics of the child's organism. In some situations it is sufficient to perform balloon angioplasty with stenting, but a radical option is operative correction with subsequent balloon angioplasty, which eliminates possible recoincination. At present, such a method as balloon angioplasty has good results in the form of 90% removal of signs of coarctation, in addition, this technique allows not to carry out surgical treatment in the future, but only to change the stent of the corresponding parameters according to the age of the patient.
Operative allowance is the excision of the narrowed part of the aortic vessel with the subsequent elimination of the wound defect in the form of an anastomosis or patch. The application of an anastomosis or stitching of the ends of an excised vessel is possible only in the case of coarctation of the aorta, which has a small extent. In order to eliminate complications in the form of graft rejection, modern angiosurgery implies the use of alloplastic materials, that is, the defect is closed with a patch of patient tissue excised from the left subclavian artery. When using these methods of surgical treatment, the level of postoperative lethality is no more than 1%.
Due to the use of high-tech techniques of angioplasty, at present disability in coarctation of the aorta does not exceed one year's time, after which patients are removed from the group by the decision of the VKK, but must be for life on a dispensary account with a cardiologist. Regardless of the type of surgical manual used in the early postoperative period, patients notice a significant improvement in their condition, so the main task of the operating specialist is to talk with the patient about further correction of lifestyle, nutrition, and medical treatment.
Moderate-pronounced narrowing of the aortic lumen is not accompanied by severe cardiogeodynamic complications, so even if there is no surgical treatment, these changes do not have a negative effect on the patient's life-span. Expressed coarctation of the aorta without surgical correction can adversely affect the quality of life of the patient, and the lethal outcome, as a rule, occurs as a result of complications development in the form of acute left ventricular failure, rupture of the aorta in the projection of aneurysmal expansion, bacterial endocarditis and exfoliating aortic aneurysm.
? Coarctation of the aorta - which doctor will help ? If there is or suspected coarctation of the aorta, you should immediately seek advice from such doctors as a cardiologist and cardiac surgeon.