Coarctation of the Aorta
The aorta is the major blood vessel carrying oxygenated blood to the body. Coarctation of the aorta refers to a condition where there is a tightness (or narrowing) in the aorta.
As a result, the left hand-side of the heart has to work harder to push blood out to the body against the site of obstruction.
When the condition is severe, there can be reduced blood flow to the body in these children.
Clinical Presentation
The clinical presentation is variable and depends principally upon the severity of the problem and the age of the baby or child.
Milder degrees of coarctation are often not detected until childhood or adolescence and often come to light from the incidental finding of weaker leg (femoral) pulses, a murmur or hypertension (high blood pressure).
The condition can present in the newborn period from the finding of reduced femoral pulsation during the standard newborn baby check, or babies may present suddenly and be very sick, with reduced body body flow, in cases of tight coarctation.
The condition may only reveal itself at a few days or weeks of age following the closure of the ductus arteriosus (one of the fetal ‘safety features’ that we all that usually closes shortly after birth).
Prenatal diagnosis (during pregnancy) is possible and may direct medical staff to recommend delivery in a specialist centre, with advice given to start a special medication to promote postnatal patency of the ductus arteriosus (fetal ‘safety feature’) prior to detailed postnatal cardiac evaluation
Presentations
Investigations
Echocardiography
A paediatric cardiologist can make the diagnosis with echocardiography. This helps to visualise the aorta, characterise the site and degree of narrowing (coarctation) and assess the vessel for poor growth (hypoplasia). The haemodynamic effects on the other cardiac structures are also quantified together with the overall performance of the heart and circulation.
12 lead ECG
An electrocardiogram (ECG) is also performed to assess for thickening (hypertrophy) of the left ventricle.
24 blood pressure monitoring
Is sometimes employed to assess the blood pressure over a longer (more meaningful) time-course.
Exercise Test
A paediatric cardiac exercise test with blood pressure monitoring is sometimes requested to assess the blood pressure response to peak exertion.
Treatments
Medical follow-up alone
Mild and moderate degrees of coarctation require medical supervision for children in an outpatient capacity. If coarctation progresses in severity, or produces symptoms or structural changes in the heart this usually warrants child heart surgery or a key-hole (catheter based) intervention to alleviate the symptoms and protect from clinical deterioration.
Key-hole procedure
(cardiac catheterisation with balloon dilatation +/- stent placement). If suitable, a catheter procedure may be employed by the doctor to treat coarctation and avoid the need for child heart surgery.
A short anaesthetic is given, after which a cannula (or drip) is sited into the blood vessel in the groin. A thin tube (catheter) is then advanced into the leg and then towards and into the heart using special x-rays. A special catheter balloon is then deployed across the coarctation region and gently inflated to stretch the area of tightness. If needed and suitable, a stent (collapsible metal tube) is sometimes deployed across the coarctation shelf to provide structural integrity. Patients are discharged home the same day.
Child Heart Surgery
Surgery is reserved for haemodynamically important lesions that are not amenable to catheter intervention. The aim of surgery is to improve flow across the aorta by alleviating the site of obstruction. The type of operation and surgical approach depend upon the nature of the coarctation, presence of arch hypoplasia and age of the baby or child
Follow up
The long-term outlook is usually good but heavily dependent upon the severity of the coarctation, nature of the repair and presence of associated lesions such as arch hypoplasia or other left heart problems. Many children have only one intervention (catheter or surgical). Some children require further surgical or catheter procedures throughout childhood. Close serial assessment is therefore required to monitor on-going good health and anticipate the need for re-intervention.
