Sunday, June 11, 2017

Ductus Arteriosus : Review of Key Points

Hi everyone ! Just a short review on Ductus Arteriosus.

- Ductus Arteriosus is basically a communication between the Pulmonary trunk and the Systemic Aorta.
- This communication is between pulmonary trunk and the end of Arch of aorta. Just after the Brachiocephalic trunk , and Left Common carotid and Subclavian have branched off.
- In embryonic life this communication helps transport blood from RV- Pulmonary artery to the Systemic circulation.

So ,
Remember :
Prostaglandins Persist

-Prostaglandins, especially PGE1 , act on the Ductal muscle tissue and keep it Open.
-So the Ductus arteriosus stays open.

-This is important in certain Duct dependent lesions
- Duct dependent heart lesions are those which need the presence of an Open ductus to receive blood in systemic / Pulmonary circulation.

- For example -->
✓ Duct dependent lesions for Systemic Circulation are those that cause obstruction to the Left side heart to pump blood into the aorta. These include :

- Coarctation of Aorta ( especially pre Ductal ) : Here there is a constriction of the aorta just before the ductus Arteriosus. So , a persistent Ductus would transport blood from pulmonary circulation into the systemic. 
If ductus gets closed , there would be minimal blood flow to the Lower limbs and abdomen.

- Critical Aortic stenosis.
- Left side Hypoplastic heart.

~~~~~~~~~~~~~~~~~~~~~~~~~

✓ Duct dependent lesions for pulmonary circulation
-These are lesions where pulmonary blood flow would be severely reduced due to some RV- Outflow tract Abnormality and the only source to the lungs would be through the ductus shunting some blood from aorta into the pulmonary vein.

- These include : 

- Critical Pulmonary Stenosis
- Hypoplastic Right heart syndrome
- Tetrology of Fallot
- Tricuspid Atresia
- Ebstein Anomaly

Another important disease is Transposition of the great vessels where this sort of corrects the defect.
~~~~~~~~~~~~~~~~~~~~~~~~~

So. We've seen in what conditions we'd like to keep the Ductus Arteriosus open / persistent.
Normally this Ductus closes functionally within 24 hours of birth. And anatomically between 10 and 14 days post natally.

If this persists on its own for a long time it causes a Congenital Heart Disease called Patent Ductus Arteriosus.
This defect is characterised by shunting of blood into the pulmonary trunk constantly during systole and diastole causing a Continuous murmur.

To close this ductus , we could try using Indomethacin / Ibuprofen especially in preterm children.
These drugs inhibit Prostaglandin synthesis , thus causing Ductus Smooth muscle to constrict and eventually close.

So that's all about the ductus !

Happy studying !
And Stay Awesome !

~ A.P.Burkholderia

3 comments:

  1. Thanks a lot. I was about to ask for this post.Now I understood the basics.Thanks a lot:)

    ReplyDelete

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