D-Transposition of the Great Vessels

Question 1

In D transposition, the AO arises ____ from the ____ ____ and the PA arises ____ from the ____ ____.

Answer 1

anteriorly, right ventricle

posteriorly, left ventricle

Question 2

Why is this defect so fatal?

Answer 2

Because oxygen rich blood is only filtered through the lungs and venous blood is repeatedly filtered systemically.

Question 3

Measures taken at birth to correct this defect:

Answer 3

1. create ASD
2. Keep PDA open
3. Infant immediately intubated
4. Surgery

Question 4

Surgical procedure for TGA

Answer 4

1. Pallative ASD, VSD, keep PDA open
2. Jantene Procedure: Arterial switch and reconstruct LVOT
3. Coronaries reattatched
4. ASD and VSD closed
5. PDA ligated

Question 5

Cause of TGA

Answer 5

1. Conal and Truncal swellings grow in the wrong direction and in the wrong position
   - AO did not line up with the LV
   - Truncus doesn’t rotate correctly and does not line up with the ventricles

Question 6

The only mixing of blood from the right to left side is via:

Answer 6

ASD, VSD and PDA

Question 7

Clinical features of D-TGA

Answer 7

1. Hypoxic state
2. Respiratory distress and failure
3. HR increases
4. Vessels dilate
5. Increase right heart pressures (because RV is pumping systemically)