Truncus Arteriosus

Question 1

What is truncus arteriosus (TA)?

Answer 1

A rare form of congenital heart disease occurring in 1-3% of patients with congenital heart disease

TA results from incomplete or failed septation during fetal development.

Question 2

What does the embryonic truncus arteriosus give rise to during fetal development?

Answer 2

The aorta and the pulmonary trunk

This process is crucial for the proper separation of systemic and pulmonary circulation.

Question 3

What characterizes persistent truncus arteriosus?

Answer 3

A single great artery arising from the heart with a single semilunar valve that overrides the right and left ventricles

This condition leads to mixed blood flow and can cause serious complications.

Question 4

What are the main vascular outputs of the common trunk in truncus arteriosus?

Answer 4

The pulmonary arteries, systemic, pulmonary and coronary perfusion

This abnormality can lead to inadequate blood supply to the lungs and systemic circulation.

Question 5

What congenital defect is most commonly associated with truncus arteriosus?

Answer 5

Ventricular septal defect (VSD)

VSD is a common finding in patients with TA and contributes to the complexity of the condition.

Question 6

What syndrome is truncus arteriosus highly associated with?

Answer 6

22q11 Deletion Syndrome (DiGeorge Syndrome) in ~20% of cases

This genetic syndrome can lead to multiple congenital anomalies, including TA.

Question 7

What is the most common subtype of truncus arteriosus?

Answer 7

Type I/A1, found in ~60% of patients with Truncus Arteriosus

This subtype is characterized by specific anatomical features that distinguish it from other types.

Question 8

What is the primary reason for surgical repair in truncus arteriosus?

Answer 8

Likely development of congestive heart failure

If left untreated, patients can experience severe complications leading to death.

Question 9

What percentage of patients with untreated truncus arteriosus may die in infancy?

Answer 9

Up to 88%

Death is often due to heart failure from truncal valve regurgitation or pulmonary overcirculation.

Question 10

What surgical procedure is typically performed to repair truncus arteriosus?

Answer 10

Rastelli operation

This operation involves multiple steps to correct the defects associated with TA.

Question 11

What does the Rastelli operation involve?

Answer 11

Closing the VSD via a baffle patch, removing branch pulmonary arteries from the common trunk, connecting to a right ventricle to pulmonary artery conduit, and potentially repairing the truncal valve

Each step addresses critical aspects of the condition to improve patient outcomes.

Question 12

Fill in the blank: Truncus arteriosus has a high association with _______.

Answer 12

22q11 Deletion Syndrome

This association is significant in the context of congenital heart defects.

Question 13

What is the Collett and Edwards system?

Answer 13

The earliest form of classification for pulmonary artery anomalies, developed in 1949.

Question 14

What characterizes Type I in the Collett and Edwards classification?

Answer 14

The main pulmonary artery is present and bifurcates into the left and right pulmonary arteries.

Question 15

How do the right and left branches arise in Type II of the Collett and Edwards system?

Answer 15

They arise adjacent to each other from the posterolateral segment of the common trunk.

Question 16

Describe the origin of branches in Type III of the Collett and Edwards classification.

Answer 16

The right and left branches originate separately from the right and left lateral segments of the common trunk.

Question 17

What is unique about Type IV in the Collett and Edwards classification?

Answer 17

Neither of the branches arise from the common trunk, but are perfused by aortopulmonary collaterals.

Question 18

Type IV in the Collett and Edwards system is now categorized as a form of _______.

Answer 18

[pulmonary atresia with a ventricular septal defect]

Question 19

What is the basis of the Van Praagh classification system?

Answer 19

It is based on where the branch pulmonary arteries arise from the trunk, the development of the aortic arch, and the presence of a patent ductus arteriosus (PDA).

Question 20

What modifiers can be included in the Van Praagh classification types?

Answer 20

Types may include a modifier ‘A’ (with VSD) or ‘B’ (intact ventricular septum).

Question 21

Describe Type 1 of the Van Praagh classification.

Answer 21

The main pulmonary artery is present and bifurcates into the left and right pulmonary arteries.

Question 22

How does Type 1 of the Van Praagh classification compare to other classifications?

Answer 22

It is the same as the Collette and Edwards classification.

Question 23

Describe Type 2 of the Van Praagh classification.

Answer 23

The right and left branch pulmonary arteries arise from the common trunk.

Question 24

Describe Type 3 of the Van Praagh classification.

Answer 24

One branch pulmonary artery (typically the right) arises from the common trunk, and the other arises from a PDA or the aorta.

Question 25

Describe Type 4 of the Van Praagh classification.

Answer 25

It is defined by the presence of aortic arch hypoplasia, coarctation or interrupted aortic arch, and a large PDA.

Question 26

What is a Ventricular Septal Defect (VSD)?

Answer 26

A VSD is a defect present in the vast majority of cases, usually large and conoventricular. ## Footnote VSDs are common congenital heart defects characterized by a hole in the ventricular septum.

Question 27

What percentage of patients with TA have a right aortic arch?

Answer 27

Approximately 30% of patients with TA have a right aortic arch. ## Footnote TA refers to a condition known as truncus arteriosus.

Question 28

What percentage of patients with TA have aortic arch hypoplasia or an interrupted aortic arch?

Answer 28

12% of patients with TA have aortic arch hypoplasia or an interrupted aortic arch.

Question 29

What are the common characteristics of truncal valve anomalies?

Answer 29

The leaflets are usually thickened, and the valve is most commonly tricuspid. ## Footnote Other variations include bicuspid, quadricuspid, or rare pentacuspid valves.

Question 30

What are some examples of coronary artery anomalies?

Answer 30

Examples include atypical origin, single coronary, or narrowed ostia resulting in coronary stenosis. ## Footnote These anomalies can lead to significant cardiovascular complications.