Coarctation Of The Aorta – Diagnosis And Treatment
Coarctation of the aorta is defined as a stenosis on aortic track present at birth, which can be anatomically located in the aortic arch, descending aorta or abdominal aorta. The most common form of coarctation of the aorta is the one in which the narrowing is found distal from the origin of left subclavian artery. The incidence of coarctation of the aorta is 5% – 10% of all congenital cardiac malformations. Can appear as isolated injury or associated with: bicuspid aortic valve, patent ductus arteriosus, ventricular septal defect, Turner syndrome, aneurysms of Willis polygon and hemangiomas.
Pathophysiology of coarctation of the aorta:
Hemodynamic manifestations depend on the degree of stenosis, presence of other associated defects and the presence of ductus arteriosus. The presence of an narrow area at the level of aorta, will create a anatomically barrier and a functional gradient between the above are and the distal area . So the above area will be permanently hypertensive and the distal area hypoperfused. To maintain an adequate circulation, distal to the abdominal organs, the body will develop a collateral circulation through intercostal arteries and mammary arteries.
Diagnosis of coarctation of the aorta:
Coarctation of the aorta can be suspected by clinical examination, due to stenosis severity and the association with other defects and is confirmed by paraclinical investigations. Presence of hypertension in young people, can attract attention. Pulse can be well beaten in radial arteries and decreased and late in the femoral arteries. On auscultation in the interscapular space is charged a intense systolic murmur. The presence of collateral circulation give a crescendo-descrescendo murmur. If coarctation of the aorta is associated with bicuspid aortic valve (40% of cases), then will appear a aortic regurgitation murmur.
- ECG -signs of left ventricular hypertrophy.
- Chest radiography – In children, X-ray shows cardiomegaly and signs of pulmonary stasis. In adolescents and adults may be present the classical, pathognomonic sign of coarctation of the aorta – coastal erosion (coastal rosary) and signs of left ventricular hypertrophy with increased cardiac shadow.
- Echocardiography – performed 2D, color Doppler, is helpful in diagnosis of coarctation of the aorta by identifying the area of stenosis and will calculate the presional gradient.This investigation is helpful for the exploration of aortic valve, mitral valve, interatrial and interventricular septum integrity, the reaction of the left ventricle and is an indispensable examination. Prenatal detection by fetal Echo is quite difficult, although exist indirect signs that are suggesting the possibility of coarctation of the aorta.
- MRI – Provides images with high accuracy, identify the anatomical form and the location of the coarctation of the aorta and the presence of collateral circulation. It is mainly used for the postoperative tracking of restenosis or the development of a local aneurysm.
- Cardiac catheterization – is rarely necessary in children. It is used to exclude other associated defects when echocardiography and clinical status are inconsistent. In adults over 45 years is indicated to assess the coronary arteries. Cardiac catheterization is use to measure the pressional gradient from the narrowing. Gradient below 20 mmHg, shows a medium coarctation of the aorta and more than 20 mmHg indicate surgical solution.
Natural evolution of coarctation of the aorta:
In severe forms of coarctation of the aorta associated with other defects, the child may present at birth congestive heart failure, severe acidosis, distal hypoperfusion. In these cases, is needed immediate and complex treatment both medical and surgical. Asymptomatic forms can reach adulthood in the third or fourth decade of life when they are detected because of elevated blood pressure, intense headache, epistaxis, cramps or bleeding strokes. Causes of death include: coronary heart disease, rupture / dissection of aorta, endocarditis, aortic valve lesions, intracerebral hemorrhage.
Treatment of coarctation of the aorta:
Medical – in infants with severe stenosis, congestive heart failure, renal failure, metabolic acidosis, medical urgent measures are needed: resuscitation, intubation, infusion of prostaglandin to keep the ductus arteriosus permeable and interventional or surgical procedures (balloon dilatation).
Surgical – It is necessary at any age, urgent to save newborn lives or elective to prevent complications of coarctation of the aorta. There are several surgical techniques that attempt to resolve the area of stenosis.
Interventional method – can be made of emergency in infants with critical situation, when is trying the dilation of the area with stenosis, with a balloon. Shall be made in adults with dilation and stent placemen, in case of postsurgical restenosis. In case of an aneurysmal dilatations may be inserted a stent-graft.
Postoperative complications can be: damage of the recurrent or phrenic nerve, chilotorax, hypertensive crisis, paralysis by medullary ischemia. In the long run, especially when the surgical intervention is done after age of 15, hypertension may persist after surgery.
Untreated coarctation of the aorta may reach the age of 35, and 20% even up to 50 years. If surgery is done before 14 years, then the survival rate to 20 years is 90% and the survival after this 20 years is 80%. Women operated by coarctation of the aorta can have children, but the pregnancy is considered with high-risk. Native or residual stenosis of the aorta is a contraindication for pregnancy.