Aortic Coarctation
- Congenital condition
- Pathological narrowing of the aorta (usually at the insertion of ligamentum
arteriosum).
- Narrowing of the vessel → increased resistance to blood flow → increased afterload
for the left ventricle (pressure that the heart must work against to eject blood) → left
ventricular hypertrophy.
- As the coarctation is located distal to the vessels that supply the head, neck and
upper limbs, blood supplying to those areas are not compromised.
- On the other hand, blood supply to the lower limbs is reduced, resulting in weakness
of the lower limbs and a weak delayed femoral pulse. → radio femoral delay
- Treatment: depends on the age of diagnosis and the severity of the condition.
- Common interventions are surgical, however balloon angioplasty and stenting may be
used as first line.
- Stenosis distal to the left subclavian artery results in hypertension (↑ BP) in the upper
limbs and the head, and hypotension (↓ BP) in the lower limbs and abdomen.
- If coarctation involves the origin of the left subclavian artery, BP in the right side of the
head, neck and upper limbs will be higher than in the left arm, lower limbs, and
abdomen.
- There are 2 forms of aortic coarctation: infant form and adult form.
7
Infant Form
- The infant form accounts for about 70% of cases.
- The coarctation comes after the aortic arch and before the ductus arteriosus– exists
=
during fetal development and closes after birth but with infantile coarctation the ductus
arteriosus is usually still open or patent; pre duck-billed coarctation.
, - When the blood is pumped out of the pulmonary artery, it could go through the patent
-
ductus arteriosus and continue down the aorta (higher pressure) OR to continue on
-
down the pulmonary artery (lower pressure).
- Due to the coarctation, the area right before the ductus arteriosus is narrower, so
blood flowing from the left side has a harder time going through it and so there's a
high pressure upstream of the coarctation but low pressure downstream.
- So, the blood decides to through the patent ductus arteriosus and into the lower
pressure area in the systemic circulation and then continue down to the lower
extremities rather than the slightly higher pressure pulmonary artery.
* Normal :
systemic circulation P > pulmonary circulation P
- Since deoxygenated blood is being delivered to the lower extremities, infants usually
have lower extremity 1--1
cyanosis.
- Without intervention, infants often don't survive past the neonatal period.
- Highly associated with Turner syndrome, a genetic abnormality where females only
have 1 X chromosome instead of 2.
2 Adult Form
- The adult form accounts for about 30% of cases.
- Typically developed as an adult and there usually isn't a patent ductus arteriosus and
instead it has been long since it closed off and is now known as theb-
ligamentum
arteriosus.
r
-
- There's no mixing of deoxygenated and oxygenated blood but similar to the infant
form, there's a high pressure upstream of the coarctation but low pressure
downstream, so blood flowing from the left side has a harder time going through it.
- Upstream issues
● Blood flow increases into the aortic branches and therefore blood pressure
increases in the head, neck and upper limbs.
➢ Increased cerebral blood flow means an increased risk of berry
aneurysms.
● Increased pressure causes the aorta and aortic valve to dilate, increasing the
risk of aortic dissection. -
E
- Congenital condition
- Pathological narrowing of the aorta (usually at the insertion of ligamentum
arteriosum).
- Narrowing of the vessel → increased resistance to blood flow → increased afterload
for the left ventricle (pressure that the heart must work against to eject blood) → left
ventricular hypertrophy.
- As the coarctation is located distal to the vessels that supply the head, neck and
upper limbs, blood supplying to those areas are not compromised.
- On the other hand, blood supply to the lower limbs is reduced, resulting in weakness
of the lower limbs and a weak delayed femoral pulse. → radio femoral delay
- Treatment: depends on the age of diagnosis and the severity of the condition.
- Common interventions are surgical, however balloon angioplasty and stenting may be
used as first line.
- Stenosis distal to the left subclavian artery results in hypertension (↑ BP) in the upper
limbs and the head, and hypotension (↓ BP) in the lower limbs and abdomen.
- If coarctation involves the origin of the left subclavian artery, BP in the right side of the
head, neck and upper limbs will be higher than in the left arm, lower limbs, and
abdomen.
- There are 2 forms of aortic coarctation: infant form and adult form.
7
Infant Form
- The infant form accounts for about 70% of cases.
- The coarctation comes after the aortic arch and before the ductus arteriosus– exists
=
during fetal development and closes after birth but with infantile coarctation the ductus
arteriosus is usually still open or patent; pre duck-billed coarctation.
, - When the blood is pumped out of the pulmonary artery, it could go through the patent
-
ductus arteriosus and continue down the aorta (higher pressure) OR to continue on
-
down the pulmonary artery (lower pressure).
- Due to the coarctation, the area right before the ductus arteriosus is narrower, so
blood flowing from the left side has a harder time going through it and so there's a
high pressure upstream of the coarctation but low pressure downstream.
- So, the blood decides to through the patent ductus arteriosus and into the lower
pressure area in the systemic circulation and then continue down to the lower
extremities rather than the slightly higher pressure pulmonary artery.
* Normal :
systemic circulation P > pulmonary circulation P
- Since deoxygenated blood is being delivered to the lower extremities, infants usually
have lower extremity 1--1
cyanosis.
- Without intervention, infants often don't survive past the neonatal period.
- Highly associated with Turner syndrome, a genetic abnormality where females only
have 1 X chromosome instead of 2.
2 Adult Form
- The adult form accounts for about 30% of cases.
- Typically developed as an adult and there usually isn't a patent ductus arteriosus and
instead it has been long since it closed off and is now known as theb-
ligamentum
arteriosus.
r
-
- There's no mixing of deoxygenated and oxygenated blood but similar to the infant
form, there's a high pressure upstream of the coarctation but low pressure
downstream, so blood flowing from the left side has a harder time going through it.
- Upstream issues
● Blood flow increases into the aortic branches and therefore blood pressure
increases in the head, neck and upper limbs.
➢ Increased cerebral blood flow means an increased risk of berry
aneurysms.
● Increased pressure causes the aorta and aortic valve to dilate, increasing the
risk of aortic dissection. -
E
