What happens when there is a Coarctation of the aorta ?

The sequence of events is like any condition where there is an obstruction to smooth blood flow. When the aorta is narrow, blood flow across the coarctation is obstructed. As a result, the blood pressure builds up in the arterial branches BEFORE (or PROXIMAL) to the CoA. At the same time, blood flow is DECREASED in the part of the aorta BEYOND the area of CoA. Let's discuss these two effects separately.
Pressure builds up PROXIMAL to the CoA. The LEFT VENTRICLE, which is the heart chamber that pumps blood into the aorta and other branch arteries, now has to work AGAINST THIS HIGH PRESSURE. In other words, it has to do MORE WORK than normal. As we have seen in other conditions, the heart cannot sustain this increased effort forever without showing abnormal changes. At first, the wall of the left ventricle becomes thicker, in order to pump blood with more force. This is called HYPERTROPHY of the ventricle. For awhile, this helps the ventricle pump blood against high pressure and resistance - but not for very long. When the limit of tolerance is reached, the ventricle begins to "fail". This means it can no longer pump blood efficiently, and it begins to become LARGE and WEAK.
This is a very bad sign, for if the left ventricle fails, the rest of the body will not receive enough blood and oxygen to carry on working normally. It is manifested by the patient developing breathlessness on exertion (or even at rest) and early fatigue.
And the left ventricle is not the only structure to be affected by this narrowing of the aorta. The portion of the aorta PROXIMAL to the CoA, and its branches are also exposed to this high pressure. This is one of the reasons why children with CoA have a HIGH BLOOD PRESSURE recorded in their upper limbs. Because of this high blood pressure, changes occur in the walls of these blood vessels. The changes are similar to those in older adults with HYPERTENSION - or high blood pressure. They include thickening and deposition of fats in the artery wall, and hardening of the arteries. If allowed to continue without correction of CoA, this will eventually result in narrowing and complete block of the branch arteries, with a catastrophic outcome.
Another risk, especially in the blood vessels inside the brain, is that they may suddenly burst from the high pressure inside them. This may result in a STROKE.
Also, the coronary arteries that supply the heart with blood may be narrowed. This hastens the onset of heart failure, and may even cause a "heart attack" at a young age.

And what about the parts of the body BEYOND the coarctation area ? Find out .....

 

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