Definition and Overview
Coarctation of the aorta is a congenital heart condition characterised by the narrowing of the aorta. Aorta is a major artery responsible for carrying blood from the heart to the rest of the body. Also referred to as aortic stenosis, the condition occurs when the baby’s aorta fail to develop correctly during pregnancy. The narrowing can occur before or after the ductus arteriosus, a blood vessel that connects the pulmonary artery and aorta to bypass the foetus’ not yet functioning lungs to send blood directly to the body. The condition can also occur on the part of the aorta where the arteries branch off to deliver blood to the arms and head.
If the narrowing is severe, the patient will have to undergo various procedures, including surgery soon after birth. If left untreated, the condition can weaken the heart muscle, which can eventually lead to heart failure.
Aortic coarctation may occur as an isolated defect. However, in some cases, it develops with other heart conditions. The most common are ventricular septal and bicuspid aortic valve defects. In very rare cases, the condition develops alongside Tetralogy of Fallot, which is characterised by the presence of defective septum between the ventricles. It is accompanied by cyanosis and narrowing of the pulmonary artery.
Causes of the Condition
A basic understanding of the anatomy of the aorta is necessary to understand how aortic coarctation develops. The aorta, which measures about a foot long, is the largest artery in the body. It begins at the top of the left ventricle. It is divided into four sections, namely:
Ascending aorta - The part that begins at the base of the left ventricle. It is two inches long and rises up from the heart.
Aortic arch - This gives rise to aortic branches that supply blood to the arms, neck, and head.
Descending thoracic aorta - The part that travels down the chest and supplies blood to the ribs and other structures in the chest.
Abdominal aorta - The part that starts from the diaphragm and splits into paired iliac arteries in the lower abdomen.
Aortic coarctation can occur in any of the four sections. If this happens, normal blood flow to the body is blocked. As the blood is unable to pass through the aorta, it flows back to the left ventricle, which is then forced to work harder to push the blood out of the heart.
The reasons why narrowing develops in some parts of the aorta remain unknown. What is known, however, is that most cases begin before birth. In rare cases, the condition can develop later in life usually due to traumatic injury to the chest area or hardening of the arteries.
Aortic coarctation is more common in patients suffering from certain genetic disorders and those who have a weak area in the wall of blood vessels in their brain.
Patients suffering from this condition exhibit different symptoms depending on how much blood flows through their artery. These may include increased irritability, difficulty feeding, breathing fast, pale skin, increased sleepiness, and being less responsive compared to other infants their age. These symptoms can manifest in the first few days of life.
In milder cases, patients do not experience any symptoms until they reach adolescence. These include poor growth, shortness of breath, failure to thrive, high blood pressure, fainting, muscle weakness, and chest pains.
Who to See and Types of Treatments Available
Patients suffering from coarctation of the aorta are managed by paediatric cardiologists. Severe cases are diagnosed during infancy while mild cases are often discovered when patients reach adolescence and start to experience symptoms mentioned above.
There are various tests that are performed to confirm a diagnosis of coarctation of the aorta. These include:
Echocardiogram - This is a type of ultrasound test that produces images of the heart using sound waves. It is a standard test in cardiology that allows doctors to monitor how the heart and its valves are functioning. It is often performed to detect heart defects in unborn babies and assess the condition of the heart’s muscle following a surgical procedure.
Electrocardiogram - Also known as ECG or EKG, this non-invasive and painless test is performed to record the electrical signals of the heart. In patients with severe cases of coarctation of the aorta, the test will show enlarged walls of the lower heart chambers.
Magnetic resonance imaging (MRI) and computerised tomography (CT) scan - These imaging tests produce detailed images of the heart and blood vessels. In patients with coarctation of the aorta, these tests are used to determine the location of the narrowing and whether or not the patient has another heart problem.
Available treatments for the condition include balloon angioplasty and surgery to widen or remove the narrowed part of the aorta. In balloon angioplasty, the surgeon inserts a small balloon catheter in the wrist or groin to widen the narrowed part of the aorta. A stent is then placed to prevent the artery from narrowing again in the future. If the narrowed part of the aorta has been removed through a surgical procedure, the two free ends are reconnected to restore proper blood flow. If a large part of the aorta has been removed, doctors will use a graft to fill the gap.
In the majority of cases, patients experience quick symptom relief after their aorta has been repaired. However, there is a high risk of recurrence especially for people who have undergone surgery as a newborn. For this reason, life-long follow-up with a cardiologist is necessary.
Surgical treatment for coarctation of the aorta has risks and complications. These include rupture of the aorta, development of coronary artery disease, bleeding in the brain, stroke, kidney problems, heart failure, and paralysis of the lower half of the body.
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