Shunt pressures

My 15 month old has a 5-6 mm membranous vsd with tricuspid valve tissue partially closing the hole. Due to this tissue making the hole more restrictive, she has remained asymptomatic and hasn't required medication thus far. She has grown well during this past year and really has had no issues with having the vsd. She does have mild left sided heart enlargement.
Today we had our first cardiology appointment in six months. The pressure across the hole six months ago was in the 60's and today it was in the 90's. The doctor said that means the hole is more restrictive now, like the tissue has closed the hole more.
Is the pressure an indicator at all if the hole might close? Obviously they cannot predict, and I know that the rates of natural closure of membranous vsd's are not that high. But I was just wondering if the flow being at a higher pressure at this visit was a good sign that it could perhaps close spontaneously. Are they any indicators that a hole might go on to close?

[Marie M Gleason, M.D.]

Pediatric cardiologists use pressure gradients across VSD shunts to try to estimate the pressure in the lungs.  This is important because significant VSDs will raise the pressure in the lungs. This can lead to permanent lung damage and pulmonary hypertension if the VSD is left uncorrected.  If there is a high pressure gradient across a VSD (usually more than 60 mmHg) that tells the doctor that the pressure in the lungs is likely in the normal range.  If that is the case, then it allows you time to watch the VSD and see if nature can close the hole further over time.   The amount of the pressure gradient does not dictate whether or not the hole will close.  In fact, in some cases, the heart chambers remain enlarged over the years despite a very restrictive hole.  The decision for surgical intervention is a combination of things including whether the heart chambers fail to normalize in size, if the lung artery pressure is elevated, or if the child has cardiac symptoms or failure to thrive.  So far it sounds like watchful waiting is the right thing to do here.

[Dani423]

I'm adding on since this hasn't been answered yet- reading older posts has me just wanting to understand the shunt pressures more. Aside from my specific question above, what do the pressures mean in general? Is a higher number "better" for the patient? I know our doctor made it sound like in this case that it was a good thing. He did say that if it were too high though that it would mean the heart was working too hard.

[mshanson]

The numbers you have there is the VSD pressure gradient or differential. It's the pressure of the blood flow through the VSD. The higher the number generally indicates a restrictive or smaller VSD (the bigger the holes/less restriction the lower the number). My daughter's right now is at 68mmhg

[Dani423]

Doctor, thank you so much for the response, it is immensely appreciated!
You touched on something I had been thinking of- the fact that the left side of her heart is still enlarged despite the restrictive hole. Does the enlargement typically return to normal once the hole is very restrictive? Does it take long?
I know you said in some cases it doesn't normalize. Would it normalize after surgery? Her left sided enlargement has been so mild that she hasn't required medications thus far. I still worry though- are there any complications that arise from sustained enlargement?

Thanks again, this forum is an amazing and invaluable resource to us parents!

[Marie M Gleason, M.D.]

If the left heart is not enlarged enough for your doctor to start medication, that is a good sign that it is mild.  After surgery the chambers do return to normal.  As I said, there are some children with restricitve holes who continue to have some heart enlargement.  they are the patients who may need other evaluations as the years go by the see if there is enough blood flow across the hole to warrant surgery. Your child is quite young and has lots of time on her side.