Repair of Truncus Arteriosus

Truncus Arteriosus

Cara GuentherUndergraduate Fellow

Redmond P. BurkeChief, Division of Cardiovascular Surgery

The Congenital Heart InstituteMiami Children’s Hospital and Arnold Palmer Hospital

www.pediatricsurgery.com

What is Truncus Arteriosus? In a child with Truncus Arteriosus (TA), the embryological

structure known as the truncus arteriosus does not divide properly into the aorta and pulmonary artery.

Normally, a child has two main blood vessels leaving the heart – the pulmonary artery that supplies blood to the lungs and the aorta that supplies blood to the body.

A child with Truncus Arteriosus, however, has one large vessel, or truncus, that leaves the heart and later splits to supply both the lungs and body with blood. Usually this vessel only has one large valve, known as the truncal valve.

Children with Truncus Arteriosus also have a ventricle septal defect (VSD), or a hole in the septum separating the left and right ventricle. The child’s truncus sits on top of this opening.

Information from http://www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/truncus.htm

Normal Heart vs. Heart with Truncus Arteriosus

Normal Heart Heart with TA

Images from www.americanheart.org

*Please note the completely separate pulmonary artery and aorta as well as the continuous ventricular septum.

*Please note the single large vessel (truncus) and the hole in the ventricular septum (VSD)

What are the different types of Truncus Arteriosus?

In 1965 van Praagh proposed four different types of Truncus Arteriosus.Type A1: Single pulmonary trunk originates from the left

lateral aspect of the truncus, with branching of left and right pulmonary arteries from the pulmonary trunk.

Type A2: Left and right pulmonary artery branches have separate origins on the lateral aspects of the truncus.

Type A3: One branch of the pulmonary artery stems from the truncus whereas the other branch originates from the aortic arch

Type A4: Defined by the coexistence of an interrupted aortic arch.

Information from http://emedicine.medscape.com/article/892489-overview

Diagram of different types of Truncus Arteriosus

Image from http://emedicine.medscape.com/article/892489-overview

How does Truncus Arteriosus affect my baby’s heart and

health?All the blood that leaves the heart can now flow

either to the body or lungs. At a young age, more blood tends to flow to the lungs which requires the heart to work a lot harder. Overtime, the extra blood flow damages the vessels in the lungs and causes pulmonary hypertension.

The truncal valve can also put extra stress on the heart by leaking or blocking the blood’s path out of the heart.

Truncal valve

Leaflets

Image from www.irounds.mch.com

What are the symptoms of Truncus Arteriosus?

Low oxygen levels, often causing the child’s skin turning a light hue of purple or blue, known as cyanosis.

On an X-ray, the heart appears very large since the muscle thickens from the extra work and the lungs are hazy due to the excess amount of blood flowing into the lungs

Rapid breathingPoor feeding

Information from http://www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/truncus.htmz

What happens if the Truncus Arteriosus is not fixed?

Over time, the lung’s arteries will become damaged, causing the child to have pulmonary hypertension.

Congestive heart failure (when the heart pumps too much blood to the lungs and they fill with fluid. This makes it difficult for a child to breathe, so they breathe rapidly. When a baby breathes rapidly, it can’t suck, and therefore cannot feed. The baby loses weight, and this is called “failure to thrive”).

Information from http://www.pted.org/?id=truncusarteriosus3

How does my team diagnose Truncus

Arteriosus?

The presence of one large vessel, one valve, and a VSD on an esophageal echocardiogram illustrates that a child has Truncus Arteriosus.

Nevertheless, this diagnosis must be discussed with my whole team during a conference before the operation can take place. Each patient is different, so every case is analyzed thoroughly by multiple experts before any surgical procedures are done.

In conference, we refer to the results of our previous patients and surgeries for clinical decision making. All of our outcomes are reported on our website www.pediatricheartsurgery.com

Our Mission

To successfully treat each patient with the most effective and least traumatic approach available!

Surgery: Steps 1-3

Open chest, harvest pericardium, and place patient on heart-lung bypass.

Aortic cannula

Venous cannula

IVC cannula

This patient is now on heart-lung bypass


Surgery: Step 4

Disconnect pulmonary artery from truncus.


Truncal transection

Surgery: Step 5

Suture where pulmonary artery was disconnected from truncus.

Truncus

Pericardial patch sutured to truncal defect


Surgery: Step 6

Close VSD either with a continuous suture line and a patch cut from harvested pericardium.


VSD repair with running suture line

Surgery: Step 7

Connect the right ventricle to the lungs. Suture a conduit (this one is a donor aortic valve from a patient who died and donated their organs) to the distal pulmonary arteries.

Conduit connecting pulmonary artery and right ventricle


Surgery: Step 8, 9, 10, and 11

Re-warm the heart, separate from the bypass machine, insert and secure draining tubes, and possibly close the chest.


Sternal closure

Chest tube

Day 1 (Day of Operation)

Images from https://irounds.mch.com/

Postoperative Day 2


Postoperative Day 3


Postoperative Day 4


Postoperative Day 5


Postoperative Day 6


Postoperative Day 7


Postoperative Day 10

The baby is ready to go home on the 10th day after surgery!

What are my main concerns during surgery?

That the homograft is the correct length; the conduit can neither be stretched nor kinked.

That the truncal valve functions well, no leak and no obstruction.

Why do I sometimes wait to close the chest?

It is normal for the chest cavity to fill with fluid after an open heart, bypass surgery. This is why we leave one to three draining tubes in the child’s chest.

However, if I foresee a large build up of fluid or intense swelling of the heart muscle, I wait to close the chest to avoid any pressure on the heart.

If the chest remains open, antibiotics are given to reduce risk of infection. The child’s chest then is usually closed in the ICU in the first or second postoperative day.

Different types of grafts

Homograft Pulmonary homograft– comes from a human donor Aortic homograft – comes from a human donor

Zenograft Contegra – comes from bovine (Cow) donor.

Selection of type of graft depends on size and availability

My preference: Pulmonary homograft Contegra zenograft Aortic homograft

Will my child have to take immunosuppressive drugs if he/she

receives a graft from a donor?

No, not because of the graft. All three types of graft (pulmonary, aortic, and contegra) are stripped of all cell material before they are used in surgery. Therefore, immunosuppressive drugs are unnecessary.

Can my child outgrow his or her conduit?

Yes, this is a possibility. However, only 29% of my patients have needed their conduit to be replaced.

Current MCH Surgical Results for Truncus Arteriosus

Total Cases (N) 29

Surgical Mortality (N) 0

Median Age (days) 15.5

Median Weight (kg) 3.1

Mean Post-op Stay (days) 7

Delayed Sternal Closure (%) 39%

If delayed closure, mean duration of open chest (days)

2

This data represents all MCH cases since 2002.Data found in https://irounds.mch.com

More MCH Surgical Results for Truncus Arteriosus

Type A1 (%) 71%

Type A2 (%) 21%

Type A3 (%) 8%

Pulmonary Homograft used (%)

48%

Aortic Homograft used (%) 48%

Contegra Zenograft used (%) 4%

Conduit Replacement (%) 29%

Median Age at Replacement (days)

958

Interrupted Aortic Arch (%) .07%This data represents all MCH cases since 2002.

Data found in https://irounds.mch.com

Images

My team and I take intra-operative images during every surgery for two reasons:To help you understand what we did in

surgery, your family and you will receive a copy of these images. The images can also be accessed at https://irounds.mch.com

We reference these images when discussing subsequent procedures in conference.

Conclusion

Surgical repair of the Truncus Arteriosus defect is very effective and absolutely vital. We have been very successful in repairing this defect (no surgical mortalities since before 2002).

If your child has TA, expect him/her to be hospitalized for at least a week after the surgery. Also, do not be discouraged if we wait to close your child’s chest.

Documents

Repair of Truncus Arteriosus