congenital coarctation of the aorta
Introduction
Introduction to congenital aortic coarctation Congenital aortic coarctation accounts for about 5 to 8% of all types of congenital heart disease. In 1760, Morgagni discovered the disease during autopsy. Its main lesion is aortic limited short-segmental stenosis or occlusion leading to aortic blood flow disorders. The vast majority (more than 95%) of the lesions in the aortic constriction are at the junction of the distal aortic arch and the descending thoracic aorta, that is, the aortic isthmus, adjacent to the arterial catheter or arterial ligament. However, in a very small number of cases, the narrowing segment can be located in the aortic arch, the descending thoracic aorta or even the abdominal aorta. Sometimes the aorta can be narrowed in two places. Very few patients have a family history, the disease is more common in men, the ratio of men to women is 3 to 5:1. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious Complications: ventricular septal defect, patent ductus arteriosus
Cause
Congenital aortic coarctation
Pre-catheter aortic coarctation (30%):
The narrowing segment is located at the proximal end of the arterial ligament or arterial catheter. This type is relatively rare. The aortic constriction may be longer. In most cases, the arterial catheter is not closed. The degree of narrowing is severe. The blood discharged from the right ventricle passes through the pulmonary artery and is not. The closed arterial catheter enters the descending aorta and supplies the lower part of the body. The collateral circulation is less developed. Nearly half of the cases of pre-catheter aortic coarctation have congenital malformations of other cardiovascular vessels, which can be caused by heart failure in infants and young children. To death, Bonnet used to call this type of infantile aortic coarctation in his early years.
Posterior catheter aortic constriction (30%):
This type is more common. In a typical case, the aortic constriction is located in the isthmus of the distal end of the left subclavian artery. In most cases, the arterial catheter is closed, and the narrowed lesion is short and localized at the distal or immediate location of the arterial ligament. Near the narrowing, the distal aorta often shows different degrees of enlargement, the narrowing of the segment is near, the distal aorta forms a rich collateral circulation, the case of the arterial catheter is not closed, the direction of blood flow through the arterial catheter depends on the descendant The difference between arterial and pulmonary arterial pressure, about 25-40% of cases of posterior aortic coarctation, is a double-valve type, but generally there are other serious congenital heart vascular malformations. Most patients can grow into adulthood. Therefore, in the early years, Bonnet called this type of adult aortic coarctation, posterior aortic coarctation, narrowing of the segment, and the collateral circulation between the distal aorta began to form in the fetal period to increase the stenosis. The blood supply at the end, the degree of narrowing is severe, and the arterial catheter is closed. The collateral circulation is more abundant. The collateral circulation mainly comes from the enlarged bilateral subclavian artery and the internal thoracic artery. Dry, cervical transverse artery, thyroid neck, upper scapular artery, subscapular artery, upper intercostal artery, lateral thoracic artery, tendon artery, superior abdominal artery, anterior spinal artery, etc. Sometimes the subclavian artery is extremely enlarged like aneurysm The intercostal arteries involved in the formation of the collateral circulation are mainly the 4th to 7th intercostal arteries, only in the case of the subclavian artery with stenosis or the aortic constriction located at the proximal end of the subclavian artery. The arteries participate in the formation of the collateral circulation. In a very small number of cases, the aortic constriction is located in the lower middle part of the thoracic descending aorta or the abdominal aorta. The narrowing of the lesion is longer. The aorta above the lesion is gradually small and the lateral branch is The cycle is underdeveloped and not typical.
Collateral circulation (30%):
The narrowing of the aorta causes an increase in blood flow resistance, which narrows the proximal blood pressure, reduces the blood supply to the distal end of the narrowed segment, and lowers blood pressure. Gupta and Wiggers reduce the aortic lumen of the experimental animal by 50%. The systolic pressure of the aorta increased above the stenosis, and the systolic blood pressure of the aorta decreased below the stenosis, indicating that mechanical stenosis is the main cause of hypertension. Scott and Bahnson first transplanted one side of the experimental dog to the neck, and then made the experimental master. Arterial constriction, postoperative upper extremity hypertension can be relieved after removal of the kidneys with reduced blood supply below the constricted segment. In addition, clinical cases of aortic coarctation often find elevated plasma renin levels, suggesting aortic degeneration. Narrow cases present with hypertension, in addition to mechanical factors, but also related to renal ischemia, the role of renin, a part of aortic coarctation, after surgical treatment of the resected narrowing, although near, distal aortic pressure The difference has disappeared, but hypertension still persists, so some people think that this may be related to the ascending aortic wall baroreceptor or adrenal dysfunction, atrophy caused by aortic coarctation The formation of proximal hypertension and collateral circulation, as well as concomitant congenital heart vascular malformation severely affect the normal function of the circulatory system, threatening the life of the patient, common causes of death are congestive heart failure, bacterial endocarditis or Endarteritis, aortic rupture and cerebrovascular accidents, rupture of the lynx cerebral artery aneurysm, etc. According to Gross's statistics, 90% of pre-catheter aortic coarctation cases die of heart failure within 1 year of age. In the case of post-catheter aortic coarctation, according to Abbott's 1928 autopsy data, the average age at death was 32 years. Reifenstein summarized 104 autopsy data in 1947 and found that 61% of the cases died before the age of 40.
Prevention
Congenital aortic coarctation prevention
Post-catheter aortic coarctation The surgical mortality rate of various surgical treatments is generally less than 3%. Common causes of death are heart failure, pulmonary artery dysfunction and improper technical operation, massive bleeding of blood vessels or aneurysms, and infants under 1 year old due to Severe condition, operative mortality is higher than patients over 1 year old, and other congenital cardiovascular vascular malformations, increased operative mortality, with ventricular septal defect, operative mortality rate of 20 to 30%, accompanied by other serious heart In patients with vascular malformations, the operative mortality rate is as high as 50-70%.
The follow-up survival rate of patients with post-catheter aortic coarctation was more than 90% after 15 years of follow-up; only 80% of those with ventricular septal defect; 40% with other severe cardiac vascular malformations. The long-term survival rate of patients over the age of 20 is also reduced. The common causes of long-term death are: myocardial infarction, aortic valve disease, aneurysm rupture, and hypertension and heart failure caused by residual stenosis or restenosis. Surgical treatment should be performed after the diagnosis of a posterior aortic coarctation is simple. Surgical treatment should be performed as soon as possible in patients aged 3 to 4 years old. The upper limb blood pressure exceeds 20 kPa (150 mmHg) or the medical treatment of heart failure is not controlled. Immediate surgery, with other severe congenital heart vascular malformations, insufficient pulmonary function, congestive heart failure, electrocardiogram showing myocardial damage or conduction block, extensive atherosclerosis or calcification of the aortic wall, and insufficient coronary blood supply, etc. In the case, the surgical treatment should be cautious.
Complication
Congenital aortic coarctation complications Complications, ventricular septal defect, patent ductus arteriosus
Aortic coarctation often has other congenital heart vascular lesions, most commonly with patent ductus arteriosus and double-valve aortic valve, in addition to aortic stenosis, ventricular septal defect, ascending aorta dysplasia And endocardial fiber elastic tissue hyperplasia, Turner syndrome (also known as X syndrome) about half of patients with aortic stenosis, Turner syndrome is congenital ovarian hypoplasia, sex chromosome abnormalities, the main clinical manifestations are short stature, Physical growth and sexual development retardation, neck skin relaxation, gradually forming the neck, low hair and elbow valgus.
Postoperative complications: constriction resection in patients with aortic coarctation, complications that may occur after aortic anastomosis or subclavian valve aortic angioplasty:
(1) Postoperative hypertensive aortic coarctation after proper correction, most cases can still show systolic or diastolic blood pressure in the early postoperative period, which lasts for a long time, about 10% of cases are the first in postoperative Zhou Shang has abdominal discomfort, abdominal distension or abdominal pain, and can present fever, leukocytosis, abdominal tenderness and weakened bowel movements. In 1957, Sealy observed that abdominal pain was more common in 48 hours after surgery, and delayed depression was mainly caused by diastolic blood pressure. The cause of hypertension may be dysregulation of vascular wall baroreceptor; adrenaline, norepinephrine secretion increased; or plasma renin-angiotensin content, in order to prevent the emergence of hypertension, within 24 hours after surgery Intravenous infusion of sodium nitroprusside maintained the systolic blood pressure at about 14.7 kPa (110 mmHg), and switched to oral antihypertensive drugs after 24 hours.
In patients with incomplete correction or postoperative restenosis, the hypertension continues to be present, and the upper and lower limb blood pressure still has a pressure difference of 14.7 kPa (110 mmHg) or more. The clinical examination can find the femoral artery beat more than the radial artery. Or the brachial artery is weak and delayed, the lower extremity blood pressure is lower than the upper limb, and the upper and lower limb pressure difference is larger. The aortic angiography can show that the aortic lumen of the original surgical site is narrow.
The reason why the narrowing of the lesion is not relieved and the aortic stenosis persists is mainly due to improper operation, such as insufficient length of the narrowing section, small lumen of the remaining aorta, and narrow caliber after end-to-end anastomosis. The size and length of the vessel used in the transplantation are improper. When aortic angioplasty, the constricted segment of the diaphragm is not resected, the subclavian artery flap or the synthetic woven piece is not properly trimmed; when performing bypass grafting or shunting, the application The artificial blood vessel or the subclavian artery is distorted. The common cause of restenosis after operation is the aortic end-to-end anastomosis. The anastomosis does not increase with the growth of the body, forming restenosis, and narrowing in infants and young children. Segmental resection of the aortic end-to-end anastomosis, especially for the aorta throughout the week for continuous suturing and the use of non-absorbent sutures, such as silk for anastomosis, the rate of concomitant surgery is less, aortic surgery rarely occurs restenosis, surgery The tissue trauma caused by the middle vascular clamp on the aortic wall, the abnormal regeneration of the mesoderm tissue in the aortic wall, resulting in hypertrophy of the intima and middle layer of the vessel wall, and concurrent restenosis
The incidence of long-term follow-up hypertension in patients with aortic coarctation is 4 to 5 times higher than that in the general population. The incidence of long-term hypertension after surgery is higher in patients over 20 years old.
(B) spinal cord ischemic injury in the case of aortic coarctation surgery, due to the need to clamp the narrow section, the distal aorta, there is a need to clamp the left subclavian artery, resulting in reduced blood supply to the spinal cord, resulting in ischemia Sexual damage, postoperative lower limb paralysis with varying degrees of severity, but the vast majority of patients with narrowing of the proximal section, the collateral circulation between the distal aorta is rich, so ischemic spinal cord injury is rare, the rate of concomitant 0.5%, infantile aortic coarctation, constricted lesion located in the proximal left subclavian artery, with left subclavian artery root stenosis; pre-catheter type active narrowing, descending aortic blood supply from the arterial catheter; supply spinal cord An abnormal vascular anatomy, as well as a very small degree of aortic coarctation, can lead to dysplasia of the collateral circulation, excessively cut the intercostal artery during surgery, massive blood loss, lower blood pressure, and time to clamp the aorta Too long, etc., increase the risk of postoperative spinal cord ischemic damage.
Use low temperature anesthesia, try to retain the intercostal artery, shorten the time of aortic clamping, prevent excessive blood loss during operation, and reduce blood pressure. It can avoid postoperative spinal cord ischemic damage. For cases with collateral circulation dysplasia, Blood can be placed through the left heart-femoral artery, or near the distal aorta, to temporarily maintain blood supply to the lower body and spinal cord.
(3) About 5% of the cases of sterility and thoracic aortic coarctation, due to intraoperative cutting of the thoracic duct or its branches, postoperative chylothorax, chylothorax appearing early in the operation, such as chylorrhea overflow is not much, The chest drainage tube may heal after discharge, but if the chyle overflows more than one week and affects the nutritional status, it is necessary to open the chest again to find the rupture of the thoracic duct or its branches, and then suture tightly with the suture; If you find the chyle overflow, you need to find the double ligation of the thoracic duct behind the esophagus. Some cases are delayed until 1 week after the operation, and the chest X-ray should be reviewed. If the pleural effusion is found, The pleural effusion should be performed immediately to determine the nature of the effusion. After the diagnosis of the chylothorax, the pleural effusion can be repeated every 3 to 4 days. Most cases can be cured, such as multiple times. If the puncture fails to take effect, the thoracotomy or ligation of the thoracic duct is required.
(4) Aneurysm or pseudoaneurysm is a serious complication after aortic coarctation, and the pseudoaneurysm that occurs in the early postoperative period is often caused by improper suture technique, blood leakage at the suture, rupture or anastomotic bacteria. Sexual infection caused by the use of polyester woven sheets for aortic angioplasty, because the woven sheet is hard, the normal aortic wall has long been responsible for the pulsation and tension generated by blood flow, easy to form an aneurysm, a few cases due to postoperative near, far The segmental aortic wall is stripped and gradually develops to form an aneurysm.
Symptom
Congenital aortic coarctation symptoms Common symptoms Ventricular septal defect Weak systolic murmur Hepatomegaly palpitations, sputum, sputum, acute heart failure, shortness of breath, atrial septal defect
The clinical manifestations of aortic coarctation vary with the size of the constricted lesion, the degree of constriction, and whether there are other cardiac vascular malformations and different age groups.
Infancy: a case of aortic coarctation after simple catheterization. Although there is hypertension, it usually does not present clinical symptoms in infants and young children, and there are other cases of congenital malformations of cardiac vessels and pre-catheter aortic coarctation. The common clinical symptom is congestive heart failure. About half of the cases begin to show shortness of breath, heart rate, sweating, difficulty in feeding, hepatomegaly, enlargement of the heart, etc., within one month after birth. Presenting left ventricular failure, medical treatment is often difficult to control, the degree of pre-catheter aortic coarctation is severe, and the arterial catheter is thick and smooth, due to the right-to-left shunt of the descending aorta, the toes, and sometimes the left hand may present purpura and the right hand And the lip color is normal, in this case, the femoral artery beats normally, the arterial catheter area can not hear the noise, but because there is often a ventricular septal defect or atrial septal defect, the left-to-right flow in the heart chamber is large, so under the body Half of the purpura is not common, and the critically ill cases with extremely reduced left ventricular discharge may present purpura.
Examine
Congenital aortic coarctation examination
Aortic angiography can clearly determine the location of the narrowing segment, the length, the degree of aortic stenosis, the distribution of the ascending aorta and aortic arch branch and whether it is involved, the collateral circulation of the vascular condition, there is a fashion can show the patent ductus arteriosus, for typical The aortic coarctation case does not require routine aortic angiography, but for cases of narrowed lesions and long aortic coarctation, the following back can hear murmurs, and the rib notch is limited to one side or lower position. The data provided by aortic angiography facilitates the development of the surgical plan.
Electrocardiogram examination: ECG changes depend on the severity of the lesions and hypertension, and the length of the disease. ECG examination in childhood cases can be found without abnormalities. Older patients often show left ventricular hypertrophy and strain, and other cardiac vascular lesions. In addition, it can show double ventricular hypertrophy or right ventricular hypertrophy, adult cases, such as electrocardiogram showing myocardial damage or bundle branch block, should be carefully considered whether the patient can tolerate surgery.
Cardiac catheterization: The femoral artery is inserted into the descending aorta. If the narrowing section can be used to measure the proximal aortic pressure of the constricted section, then the catheter is slowly pulled out while continuously recording the aortic pressure. When the neck is narrowed, the blood pressure suddenly decreases suddenly. There is a significant pressure difference between the upper and lower aortic pressures of the narrowing section. Not only can the diagnosis be confirmed, but also the severity of the narrowed lesion can be judged. Other cardiac vascular lesions, cardiac catheterization and Cardiovascular angiography can provide important diagnostic data, and two-dimensional echocardiography can also show aortic constriction.
Diagnosis
Diagnosis and diagnosis of congenital aortic coarctation
Typical significant differences in blood pressure between the upper and lower extremities and chest murmurs may indicate the diagnosis of the disease. Echocardiography can confirm the diagnosis. The differential diagnosis should consider aortic stenosis, patent ductus arteriosus and multiple arteritis.
First, multiple arteritis
The typical clinical manifestations of multiple arteritis are not difficult to diagnose, but atypical patients need to be differentiated from other diseases. Any young person, especially a woman with more than one of the following manifestations, should be suspected or diagnosed.
1. Ischemic symptoms appear in unilateral or bilateral limbs, accompanied by weakened or disappeared arterial pulsations, decreased blood pressure or undetectable or differential pressure difference between limbs greater than 1.33 kPa (10 mmHg) or lower limb systolic blood pressure lower than upper limb systolic blood pressure less than 2.67 kPa (20mmHg) (same width cuff).
2. Cerebral ischemia symptoms, accompanied by unilateral or bilateral carotid pulsation weakened or disappeared and neck vascular murmur, but some light people, due to increased pulse pressure or increased heart rate, can be heard in the right neck And mild vascular murmurs should be differentiated from pathological murmurs according to the following characteristics: 40 years of age, especially women, and typical symptoms and signs more than a month, limbs or brain.
3. Recent high blood pressure or refractory hypertension, accompanied by high-level vascular murmurs above the upper abdomen.
4. Not obvious low fever, rapid blood sedimentation, accompanied by vascular tone, abnormal changes in limb pulse or blood pressure, and may involve pulmonary or coronary artery to cause corresponding clinical manifestations.
5. Patients with no changes in the fundus.
Second, aortic stenosis
Most patients with aortic stenosis are adults, with no history of rheumatism. Heart murmurs are often found during physical examination. Because of the strong compensatory capacity of the left ventricle, there may be no symptoms in the clinic or only complaints are prone to fatigue. Asymptomatic aortic stenosis, due to the development of the disease, symptoms gradually appear, when the left ventricular end-diastolic pressure rises, breathing difficulties occur during exercise, the head is dizzy, but within a considerable period of time, due to increased heart beat after exercise, left atrium The systolic blood pressure is increased, and the blood output can be maintained at a certain level. Therefore, the above symptoms are relatively stable. Once the exercise occurs, fainting, angina and other symptoms indicate that the condition has deteriorated.
Third, patent ductus arteriosus
The arterial catheter is a blood vessel that communicates between the pulmonary artery and the descending aorta in the fetal blood circulation. It is located between the root of the left pulmonary artery and the isthmus of the descending aorta. The normal state is more closed than the short-term after birth. If it fails to close, it is called patent ductus arteriosus. The symptoms of closure depend on the thickness of the catheter, the size of the flow, the level of pulmonary vascular resistance, the age of the patient, and the combined intracardiac malformation. Although the catheter is large in full-term infants, it needs 6-8 weeks after birth, and the pulmonary vascular resistance is decreased. Symptoms appear after the premature infants have less pulmonary arteriolar smooth muscle and lower vascular resistance, so they can have symptoms in the first week, often with shortness of breath, tachycardia and acute dyspnea, etc. Obvious, and susceptible to colds and upper respiratory tract infections, pneumonia, etc., after the child is compensated, rarely have self-conscious symptoms, but poor development, thin body, some children are only tired after fatigue, palpitations, unobstructed catheter Moderately sized patients are generally asymptomatic, until after the intense activity in their 20s, there is an air urgency, palpitations and other symptoms of decompensation of the heart function, although pulmonary hypertension However, it can occur under the age of 2, but the obvious signs of pulmonary hypertension are mostly older, showing dizziness, shortness of breath, hemoptysis, cyanosis after activity (more than half of the body is obvious), if complicated with subacute endocarditis, then There are fever, loss of appetite, sweating and other systemic symptoms. Endocarditis rarely occurs in childhood, but is more common in adolescence.
