Transposition of the Great Arteries (D-TGA)

Question 1

What is transposition of the great arteries (D-TGA)?

Answer 1

A conotruncal abnormality characterized by discordant ventricular-arterial connections.

Question 2

In D-TGA, where does the aorta arise from?

Answer 2

The right ventricle.

Question 3

In D-TGA, where does the pulmonary artery arise from?

Answer 3

The left ventricle.

Question 4

Describe the positioning of the aorta in D-TGA.

Answer 4

The aorta is anterior and rightward.

Question 5

How are the pulmonary and aortic circulations arranged in D-TGA?

Answer 5

They are in parallel instead of in series.

Question 6

What is the incidence of D-TGA in live births?

Answer 6

~31.5 in 100,000 live births.

Question 7

What is the rank of D-TGA among congenital heart diseases?

Answer 7

It is the 10th most common form of congenital heart disease.

Question 8

What is the second most common cyanotic heart disease following Tetralogy of Fallot?

Answer 8

D-TGA.

Question 9

What is the male to female ratio for D-TGA?

Answer 9

2:1 male to female ratio.

Question 10

Is D-TGA usually hereditary?

Answer 10

No, it is usually not hereditary.

Question 11

What risk factor increases the likelihood of D-TGA in infants?

Answer 11

Infants of diabetic mothers are at increased risk.

Question 12

What percentage of cases have an intact ventricular septum?

Answer 12

60%

Question 13

What percentage of cases have a ventricular septal defect (VSD)?

Answer 13

40%

Question 14

What is a common associated lesion with ventricular septal defect?

Answer 14

Pulmonary stenosis

Question 15

TGA/VSD can be associated with which type of valves?

Answer 15

Overriding or straddling AV valves

Question 16

What is a common aortic abnormality associated with congenital heart defects?

Answer 16

Hypoplastic aortic arch/Coarctation of aorta

Question 17

What type of obstruction can occur in the right ventricular outflow tract?

Answer 17

Right ventricular outflow tract obstruction

Question 18

What type of obstruction can occur in the left ventricular outflow tract?

Answer 18

Left ventricular outflow tract obstruction

Question 19

What are the usual origins of the coronary arteries?

Answer 19

RCA off right posterior sinus and LCA off left posterior sinus of Valsalva

Question 20

What is the typical source of the circumflex artery?

Answer 20

From the RCA

Question 21

What are the variations in coronary artery anatomy?

Answer 21

• Single LCA or RCA
• Inverted CAs
• Intramural coronary arteries

Question 22

What does it mean if the coronary arteries are inverted?

Answer 22

Both RCA and LCA inverted or inverted RCA and circumflex

Question 23

What can intramural coronary arteries include?

Answer 23

• LCA
• LAD
• RCA

Question 24

What is the primary diagnostic tool used prenatally for D-TGA?

Answer 24

Fetal echocardiogram

This tool is essential for visualizing the heart’s structure and blood flow.

Question 25

What is demonstrated in the apical 4 chamber sweep during a fetal echocardiogram for D-TGA?

Answer 25

Parallel great arteries with a lack of crossing of the great vessels ## Footnote This visualization is crucial for diagnosing D-TGA.

Question 26

What can cause a missed diagnosis of D-TGA in fetal ultrasound?

Answer 26

Failure to sweep to the outflow tracts ## Footnote This emphasizes the importance of a comprehensive view during the ultrasound.

Question 27

When does the diagnosis of D-TGA usually occur?

Answer 27

Shortly after birth ## Footnote This is due to the presence of parallel systemic and pulmonary circulatory systems.

Question 28

What condition can lead to more severe cyanosis in neonates with D-TGA?

Answer 28

Poor intracardiac mixing between the parallel circulations ## Footnote This can occur with a restrictive or intact atrial septum.

Question 29

What emergency procedure may be needed for neonates with severe cyanosis?

Answer 29

Urgent balloon atrial septostomy ## Footnote This procedure helps improve mixing of blood between the two circulations.

Question 30

What medication may be administered alongside balloon atrial septostomy?

Answer 30

Prostaglandins ## Footnote This is used to keep the PDA patent, facilitating another site of mixing.

Question 31

What is reverse differential cyanosis?

Answer 31

Higher saturation in lower extremities compared to upper extremities ## Footnote This occurs from right to left shunting at the PDA.

Question 32

In what conditions can reverse differential cyanosis occur in neonates?

Answer 32

D-TGA with coarctation, D-TGA with pulmonary hypertension, D-TGA with interrupted aortic arch (IAA) ## Footnote Each condition impacts blood flow and oxygenation differently.

Question 33

What is cardiac catheterization?

Answer 33

Usually done during the first day of life in setting of postnatal cyanosis ## Footnote Cardiac catheterization is a procedure used to diagnose and treat certain cardiovascular conditions.

Question 34

When is balloon atrial septostomy indicated?

Answer 34

In case of insufficient blood mixing/shunting and restrictive PFO or intact atrial septum ## Footnote Balloon atrial septostomy is a procedure used to improve blood flow in certain congenital heart defects.

Question 35

When is cardiac surgery typically performed?

Answer 35

Usually done during the first week of life to avoid left ventricular deconditioning and risk of pulmonary hypertension ## Footnote Early surgical intervention is crucial in managing congenital heart defects.

Question 36

What condition is associated with D-TGA?

Answer 36

D-TGA with intact ventricular septum or small VSD ## Footnote D-TGA stands for Dextro-Transposition of the Great Arteries.

Question 37

What is the arterial switch operation (ASO)?

Answer 37

Currently the most frequent procedure for D-TGA, involves transecting and switching the great arteries ## Footnote ASO was first successfully performed in 1975 and has been preferred since the 1980s.

Question 38

What does the LeCompte maneuver involve?

Answer 38

Positioning of the pulmonary artery and main right and left branches anteriorly to the aorta to avoid distortion ## Footnote This maneuver is part of the arterial switch operation.

Question 39

What are the Mustard and Senning procedures used for?

Answer 39

They were the palliative procedure of choice between 1960-1980s ## Footnote These procedures are used to manage conditions like D-TGA before the advent of the arterial switch operation.

Question 40

What is the principle of the Mustard procedure?

Answer 40

Utilizes pericardial patch to baffle systemic venous flow to mitral valve and pulmonary venous flow to tricuspid valve ## Footnote This procedure helps redirect blood flow in patients with certain congenital heart defects.

Question 41

How does the Senning procedure differ from the Mustard procedure?

Answer 41

Utilizes atrial tissue to baffle systemic venous return to mitral valve and pulmonary venous return to tricuspid ## Footnote Both procedures aim to redirect blood flow but use different materials.

Question 42

What are some complications of the atrial switch procedures?

Answer 42

Right ventricular dysfunction, tricuspid regurgitation, sinus node dysfunction, intraatrial reentry tachycardia, baffle obstruction ## Footnote These complications can occur in about 10% of patients one year post-surgery.

Question 43

True or False: The arterial switch operation was first successfully performed in 1980.

Answer 43

False ## Footnote The arterial switch operation was first successfully performed in 1975.

Question 44

What is the Rastelli procedure?

Answer 44

It consists of baffling the aorta to the left ventricle and using a right ventricle to pulmonary artery conduit. ## Footnote Baffling depends on the side of the VSD.

Question 45

What are the complications of the Rastelli procedure?

Answer 45

* Left ventricular outflow tract obstruction * Conduit stenosis or regurgitation * Formation of pseudoaneurysm next to the conduit ## Footnote These complications can affect the long-term success of the procedure.

Question 46

What is the Nikaidoh procedure?

Answer 46

It consists of mobilizing the aortic root and coronary arteries posteriorly, performing a LeCompte maneuver, resecting the main pulmonary artery, and replacing it with a right ventricle to pulmonary artery conduit while closing the VSD with a patch.

Question 47

What does the REV (Reparation a l’etage ventriculaire) procedure involve?

Answer 47

Main pulmonary artery and ascending aorta are detached to perform a LeCompte maneuver. Ascending aorta is reattached to the aorta, and there is baffling of the aorta to the left ventricle using the VSD. Oversewing of the pulmonary valve with detachment of the main pulmonary artery occurs with direct anastomosis of the MPA to the RV. ## Footnote This procedure allows for RV to PA connection with native tissue without a conduit.