Sunday, 24 July 2011

Understanding Coarctation of Aorta

Published in Panorama

Who is prone to Coarctation of the Aorta

35 year old Abdul Kareem from Kozhikode was admitted to the Mohandas Institute of Orthopaedic and Trauma Care Hospital in early January this year. He complained of breathlessness and fatigue and had a history of three earlier surgeries for Coarctation of the aorta. He had developed a large aneurysm of the ascending arch of the aorta with severe aortic valve leak. For the first time anywhere in the world, a complicated fourth time surgery for ascending arch aneurysm with leaking aortic value for coarctation of aorta was performed on Abdul by Dr. V.V.Bashi, Chairman, Centre for Thoracic and Cardiovascular Care, MIOT Hospitals, Chennai.

Abdul was diagnosed as suffering from coarctation of the aorta in 1984 when he was only 14 years old. He underwent an operation with grafting for the condition in a local hospital. The surgery was not entirely successful. He underwent a second surgery in 1987 for grafting again, in the aorta. In 1991, he developed aneurysm at the grafted site. He was brought in an emergency condition with vomiting of blood, to Christian Medical College, Vellore. This time round, surgery was performed on him by Dr.Bashi at Vellore. A graft was placed from ascending aorta to the abdominal aorta and he did well for 13 years till early Jan 2005, without any complications. Dr.Bashi forsees no further complications to Abdul’s condition following his fourth surgery.

What is Coarctation of the aorta and what happens to individuals suffering from this condition? Coarctation of the aorta is a congenital disorder or birth defect in which the aorta, the major artery from the heart is narrowed somewhere along its length. The most common site is just past the point where the aorta and the subclavian artery meet. The condition causes low blood pressure and reduced blood flow in the arteries that branch off below the narrowed point and high blood flow and pressure in the arteries branching off closer to the heart. The consequence of this is that there is high blood pressure in the upper part of the body and low blood pressure in the lower regions, particularly the legs. It is for this reason that both, brachial (arm) and femoral (groin) pulses are simultaneously taken in infants to diagnose the condition in the first instance.

1 out of every 10,000 babies may be born with this condition, reveals Dr.Bashi.
Aortic coarctation is more common in some genetic conditions, such as Turner's syndrome, but it can also be associated with congenital abnormalities of the aortic valve, such as a bicuspid aortic valve. It is quite common, accounting for about 15-20% of cases of congenital heart disease, and is more common in men than in women. Very rarely, it can happen secondary to infection. However, the condition can go undiagnosed until adolescence or even later. Very often, Coarctation is discovered during a newborn’s first examination or during a well-baby examination. Taking the pulses in an infant is an important part of the examination as there may not be any other symptoms or findings until the child is older.

How then does one even suspect coarctation in the first place with no manifest symptoms? Dr.Bashi explains, “That’s precisely why I wish to emphasize that one of the important aspects of school health programmes is to pick up the condition in early childhood since it is almost always congenital. Children may not manifest symptoms. But if the disorder is severe, in infancy itself it has to be corrected because the child with coarctation will have symptoms of heart failure and breathlessness – even a new born. However, if the condition is not severe and if the disorder is not proximal to the big blood vessels going to the head and neck, then the child will not have symptoms at all. It will grow up normally and the condition may get detected some time later.”

Symptoms of coarctation depend on the severity of blood flow restriction. In severe cases, symptoms are present during infancy; in milder cases, symptoms may not develop until adolescence. And when they do manifest, symptoms include decreased exercise performance, cold feet or legs, breathlessness, palpitations, fainting, dizziness, pounding headache, nosebleed, leg cramps and high blood pressure with exercise. But an individual may have the condition without any symptoms being manifest at all, even past the age of twenty years or thereabout, says Dr.Bashi.

An examination reveals high blood pressure in the arms and low blood pressure in the legs, with a significant blood pressure difference between the arms and legs. The femoral (groin) pulse may be totally absent or is weaker than the brachial (arm) pulse. A harsh murmur may be heard in the heart when listening through a stethoscope. Left sided heart failure or aortic regurgitation may be some signs diagnosed especially in infants.

Dr.Bashi explains, “If someone comes with high blood pressure at a young age, it is necessary to rule out coarctation of the aorta because if we operate upon such an individual, the chances of his blood pressure coming to normal without medicine is very high. Once brachial-femural pulse delay is observed, it is almost always certain that the condition is coarctation of the aorta and it can be confirmed by chest X ray, ECG, echocardiography and Doppler ultrasound of the aorta. In addition, CT and MRI of chest and cardiac catheterization and aortography may be indicated.”

Another distinguishing feature of individuals with coarctation of the aorta is that the upper part of the body of these individuals will appear more strong than their lower part as they grow into adulthood, at around the age of twenty to twenty five years. This is because the upper part has more blood supply. So a prominent upper part should raise suspicion of the condition, reveals Dr.Bashi.

What are the complications from Coarctation of the Aorta? There may be heart enlargement on account of the thickening of the left ventricle of the heart since it is having to exert extra pressure to pump blood harder past the obstructed area. Areas above the aortic obstruction have increased blood pressure in their arteries while the regions below the obstruction have decreased blood pressure. The kidneys are particularly sensitive to changes in blood pressure and hence may not function well. This in turn has a damaging effect on blood pressure since the kidneys help to control blood pressure. Segments of the aorta may become weak on account of the turbulent blood flow. The weakened aortic walls are prone to dilatation or aneurysms and rupture which could be life threatening. People with coarctation of the aorta, rectified or not, are at increased risk of infections of the heart and its valves because of the altered arterial wall structure. The increased blood pressure may cause the coronary arteries to narrow prematurely or have atherosclerosis. This in turn may make the individuals prone to coronary artery disease with an increased risk of heart attack or angina in early to mid adulthood.

What are the treatment options for individuals suffering from Coarctation of the Aorta? There is no medication for the condition, emphasizes Dr.Bashi. However, medication will be required to manage the associated hypertension, resulting from the condition. Surgery remains the mainstay of treatment. Treatment of children with coarctation of the aorta depends on the severity of the narrowing and when it is discovered. In children without symptoms whose coarctation is diagnosed during a routine examination, repair of the coarctation is usually recommended by the age of two years. In a newborn or infant who has congestive heart failure as a result of coarctation of the aorta, the babies are first stabilized and then surgically treated.

Various surgical modalities for the condition may be undertaken, depending on the patient’s overall health, size, location and severity of the coarctation. The narrowed area of the aorta may be removed and the two ends reconnected. Alternatively, a bypass-like graft may be placed in the area of obstruction; the area of obstruction may be removed and replaced with a graft. Whether the surgical procedure is open-heart, putting the patient on the heart lung machine or a cardiac catheterization procedure called balloon dilation using balloon to open the narrowed area, depends on the patients’ condition and how good a candidate he or she is for each process.
A surgical repair done during childhood may need to be redone in adulthood. Where timely intervention is undertaken and children are treated appropriately with surgery, their long term outlook is very good, reveals Dr.Bashi and they can lead, normal, healthy lives.


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