Interrupted Aortic Arch

Question 1

Definition

Answer 1

Characterized by an absence of a segment between the aortic arch and the descending thoracic aorta (Congenital absence of the aortic arch)

Question 2

Prevalence

Answer 2

less than 1% of all congenital heart defects

Question 3

Embryology

Answer 3

-considered an extreme for of coarctation (Type A)

-related to developmental errors of the neural chest

Question 4

How many types

Answer 4

3

Question 5

Type A

Answer 5

Interruption occurs distal to left subclavian artery (30 to 40%)

Question 6

Type B

Answer 6

Interruption occurs between the left subclavian and left common carotid artery (most common, 55-60%)

Question 7

Type C

Answer 7

Interruption occurs proximal to the left common carotid artery (rare 5%)

Question 8

pathology/physiology

Answer 8

Ductal dependent - ductus arterioles supplies blood to lower half of body

-ductus is usually left sided

-intercostal arteries may be dilated

-decreased output to the ascending aorta suggests ventricular septal defect and/or subaortic obstruction

Question 9

Associated conditions

Answer 9

• VSD
• Aortic valve deformity (bicuspid)
• MV deformity
• Subaortic stenosis
• double outlet RV
• Truncus arteriosus
• complete transposition
• DiGeorge syndrome

Question 10

History

Answer 10

Similar to severe coarctation

CHF

Peripheral pulses may be weak or absent

Tachypnea

Question 11

Physical Exam

Answer 11

may be cyanotic

differential cyanosis (pink upper body, blue lower body)

left subclavian arterial pulse may be weak or absent

tachypnea

Question 12

Cardiac Auscultation

Answer 12

Systolic murmur

Question 13

EKG

Answer 13

RVH

Question 14

chest xray

Answer 14

cardiomegaly

increased pulmonary vascularity

Question 15

Cardiac Cath

Answer 15

angiography provides detailed aortic arch anatomy- absence of the aortic isthmus

evaluates associated condition(s) (ex VSD)

Question 16

Medical management

Answer 16

Treat CHF

Prostaglandin E2

Question 17

Surgical Management

Answer 17

-anastomosis of the upper and lower segments of the aorta

-closure of VSD if present

-subaortic obstruction may have to be bypassed if subarotic diameter is less than 3 mm

Question 18

Echo views

Answer 18

Suprasternal long axis, high right/left parasternal, subcostal

Question 19

Mmode/ 2D

Answer 19

• Continuation of MPA into the DTA via the ductus arteriosus (Ductus arteriosus may be dilated)
• Prominent MPA as compared to the aorta (Asc Ao smaller than MPA)
• Identify the type of interruption (complete discontinuity between the two segments of the aortic arch)
• Malalignment VSD
• In Type B, the left common carotid is prominent and points cephalad, somewhat like a pointing index finger
• Evaluate for an aberrant right subclavian artery
• Measure the distance from the distal ascending aorta to the proximal DTA
• Determine the presence of associated lesions (VSD, Bicuspid AOV, truncus arteriosus, double outlet RV, complete transposition)

Question 20

PW/CW/Color doppler

Answer 20

• Demonstrates discontinuity of flow between ascending aorta and descending aorta
• Color flow may show total absence of high velocity jets in the descending aorta if the PDA is large
• Color flow may show a high velocity jet if the pda is restricted
• Doppler evaluation of PDA/aortopulmonary window, vsd, LVOTO
• Determine the presence and magnitude of right to left PDA shunt
• Determine the presence and severity of coexisting lesions (VSD, subaortic stenosis)

Question 21

Type B is strongly associated with

Answer 21

DiGeorge Syndrome

Question 22

Interrupted aortic arch is considered an

Answer 22

extremed form of coarctation