TeachableMedicalNews article 02262021

Teachable moment in classrooms:

  1. heart chapter – aorta and pulmonary trunk around the heart
  2. blood vessel anatomy chapter – blood vessels at the start of the pulmonary and systemic circulations
  3. blood vessel anatomy chapter – modified blood circulations in the fetus
  4. respiratory system chapter – blood vessel carrying blood to and from lungs

The news item:  the following report was published recently,

FDA approves new closure device for heart defect in premature babies

One out of 10 of all babies are born premature.

 

The article states that every year about 12,000 very low birthweight premature babies develop a disorder called patent ductus arteriosus (PDA), and that the Amplatzer Piccolo Occluder device seals an opening between two blood vessels.

So, Why Do I Care??  As the article stated 12,000 prematurely born low birthweight babies can be helped by this device. Imagine a tiny newborn whose lungs are not working properly, because not enough blood flows to the lungs. Such respiratory distress is life threatening, so a new device can give those newborns a much better chance for survival.

Plain English, Please!!!

First, let’s talk about what the ductus arteriosus is.  The ductus arteriosus is a quarter-inch long blood vessel that connects the aorta and the pulmonary trunk near the heart. Imagine that the pulmonary trunk is a river flowing to from the heart to the lung, and the aorta is a river flowing from the heart to the other organs. In this metaphor the ductus arteriosus is a canal connecting the pulmonary trunk and the aorta rivers. Such a canal is useful during fetal development, because blood is diverted from the pulmonary trunk to the aorta. That means that blood flow is diverted away from the lungs (an organ not active in the fetus) to the rest of the fetal organs.

Second, let’s talk about the patent ductus arteriosus (PDA). After birth the lungs become active, and body of the newborn automatically closes the canal to stop blood flow from the pulmonary trunk into the aorta, and thus to direct blood flow to the lungs.  In full-term babies the canal between those rivers closes a day or two after birth. In prematurely born infants the canal remains open. That continually open ductus arteriosus is the condition called patent ductus arteriosus (PDA).  This condition is harmful in a newborn, because not enough blood is flowing to the lungs, and consequently, not enough oxygen is transferred into the blood inside the lungs.

Third, let’s talk about how the device works.   The occluder itself is a black pepper-size circular structure with a wire frame, and surgical fabric covering.  The occluder is attached to the end of a catheter. Catheter plus occluder is then pushed into the circulation through the femoral vein in the groin area. Once the occluder is in the open ductus arteriosus, the catheter is detached and removed. The occluder remains in place to block the canal between those two rivers, and, so, blood flow in the pulmonary trunk will be directed to the lungs.

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