test 5 interupted aortic arch (IAA)

Question 1

Interrupted Aortic Arch (IAA)

Answer 1

• Interrupted Aortic Arch (IAA) is the absence or discontinuation of a portion of the aortic arch.
• Interrupted Aortic Arch is thought to be a result of faulty development of the aortic arch system during the FIFTH TO SEVENTH week of fetal development.
• Almost always associated with a large VSD.
- The aorta only feeds the head vessels while the ductus arteriosis feed the lower 2/3s

Question 2

Type A interrupted left aortic arch

Answer 2

• the arch interruption occurs distal (after) to the origin of the left subclavian artery.
- all head vessels perfused by aorta

Question 3

Type B interrupted left aortic arch

Answer 3

•the interruption occurs distal to the origin of the left common carotid artery.
- Left subclavian is not attached to the aorta, rather it is attached to the ductus arteriosis

Question 4

Type C interrupted left aortic arch

Answer 4

• the interruption occurs proximal to the origin of the left common carotid artery.
- The left common carotid and left subclavian not branched off of aorta, rather it is attached to the ductus arteriosis

Question 5

Interrupted Aortic Arch (IAA) Physiology

Answer 5

• During fetal development, left ventricular output supplies the arterial circulation proximal to the
interruption while right ventricular output supplies arterial circulation distal to the interruption via the left ductus arteriosus.
• Postnatally, this arrangement continues, with the addition of the pulmonary blood flow to the load of the left ventricle via the VSD.
- LV only needs to provide 1/3 of the outflow
- large portion of LV volume goes to RV via VSD

Question 6

Surgical Correction- IAA

Answer 6

• Surgical reconstruction of the arch is now relatively straightforward
• Attention is increasingly focused on the preoperative identification and surgical management of the aortic valve and subaortic stenosis found in approximately one half of cases.
- arch reconstruction (end-to-side)

Question 7

Interrupted Aortic Arch (IAA) cannulation

Answer 7

• Arterial: uses 2 aortic cannula: The arterial line is “Y’d” to allow 2 identical cannula (i.e. 2 - 8fr.) to be used to ensure an even split of flow
▫ Circulation is divided into upper and lower body
• Venous: Single Venous

Question 8

Interrupted Aortic Arch (IAA) hypothermia and cardioplegia

Answer 8

• Hypothermia: DHCA to allow arch and head vessel reconstruction (rarely antegrade cerebral and retrograde cerebral perfusion since head vessels rarely have to be cut off)
• Cardioplegia: The first cardioplegic administration is performed in the aortic root.
• Subsequent doses may be ostial