In the presence of a tightness or (stenosis) the normal flow of blood through the aorta is hindered leading to the build up of pressure behind the stenosis. If the stenosis occurs after the left subclavian this leads to decreased blood pressure in the lower limbs and high blood pressure in the upper limbs & upper 1/2 of the body. If the stenotic band is situated before the left subclavian these changes may affect the right limb and upper 1/2 of the body leading to unequal pulses and unequal blood pressure in both arms.
Coarctation of the aorta eventually leads to the development of collateral vessels (e.g. in intercostal areas) that open up as a result of the pressure build up and attempt to create alternate pathways for the blood flow around the stenotic lesion.
Symptoms and signs
High blood pressure in a young patient with or without intermittent claudication (painful legs on walking due to lack of blood supply to the legs) usually warrants further investigation. The presence of a large difference between blood pressure between upper and lower limbs and the presence of collaterals can help make the diagnosis clearer.
A harsh, late systolic murmur may be heard in the back (interscapular area) due to formation of collaterals.
- EKG shows evidence of left ventricular hypertrophy.
- Chest x-ray may show rib notching due to collaterals.
- Doppler ultrasound readily diagnosis the condition once suspected. The area of narrowing can be visualized in long axis view, along with increased velocities and turbulence at the area of coarctation.
- Transeophageal echo may help in some cases
- Angiography can measure the gradient across the coarctation.
Most patients have already been treated by childhood, rarely does it appear in adults while investigating hypertension or intermittent claudication.
Surgical correction is the 1st choice of treatment as the natural history of the disease is progressive. If the child is asymptomatic it is preferable to wait till 4-6 years of age.
In cases of recurrence a balloon is inserted in the ring to widen it.
Endocarditis prophylaxis should be given to all patients after surgical correction.
Twenty percent of patients remain hypertensive after surgical correction and require blood pressure control medications.