You have read something of defects INSIDE the heart. Now let us consider a defect that is OUTSIDE the heart itself, in one of the great arteries of the body - the AORTA.

What is COARCTATION of the aorta ?

Coarctation of the aorta (CoA) is an area of LOCALIZED NARROWING of the large artery called the aorta. ("Coarctatio" - Latin : a drawing or pressing together). The narrowing may be caused by a "shelf" of tissue inside the blood vessel which reduces its area. Alternately, it may be caused by under-development of a portion of the aorta itself, which causes a longer area of reduced diameter.

Where does CoA occur ?

The narrowing that occurs in CoA is most commonly seen at a portion called the ISTHMUS.
But what is the isthmus ? The aorta gives off arterial branches that supply the rest of the body with blood containing life-giving oxygen . The earliest branches are the CORONARY ARTERIES, that supply the heart itself. The next group of THREE arteries is called the BRACHIO-CEPHALIC group of vessels. This is because they supply blood to the upper limbs ("brachio-") and the head and brain ("cephalic"). The first of these three is the INNOMINATE artery, which supplies the right arm and right side of the face and head. The next is the LEFT COMMON CAROTID artery, which provides blood flow to the left half of the head. The third is the LEFT SUBCLAVIAN artery, which supplies the left arm. (Yes, this is the same artery used in the BLALOCK-TAUSSIG SHUNT operation for the Tetralogy of Fallot).
The portion of the aorta IMMEDIATELY BEYOND this third branch (left subclavian artery) is called the ISTHMUS. It is the narrowest portion of the aorta even normally, and in CoA it becomes even more restrictive.
Rarely, narrowing is present in other parts of the aorta - before the area of the ductus arteriosus ("pre-ductal coarctation" or "infantile" coarctation), between the carotid artery and subclavian artery, or even lower down in the aorta.

What happens when there is a Coarctation of the aorta ? Read on .....

 

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