The Nitty Gritty

This recent heart cath was done to see how Natalie's heart is progressing toward getting big enough for the Fontan and also to get a measurement of her left ventricle.  The echo that her cardiologist did in January sparked some discussion about whether her LV might have grown enough that it could support a systemic load (meaning it could function like a normal LV).  It is very rare that this happens, so we were both excited and skeptical of what we might find.

Dr. Jones told us that Natalie's pulmonary arteries are wide open and the pressures are great.  There is no narrowing at her Glen site (which is very common).  Her heart function overall looks good and at rest her oxygen saturations were in the low to mid 80's.  I found it interesting that her cath report showed her SaO2 (oxygen saturations) coming from her lungs (red blood) were 97% and then the blue blood coming from to her heart to pick up blood was 69%.  Those mixing together in the right side of her heart even out to around 80%.  Her hemoglobin is 17.1mg/dl which tells us that her body is compensating for her increasing need for oxygen as she gets bigger by increasing her oxygen-carrying ability (making more red blood cells).  Normal hemoglobin levels are between 13-15mg/dl.  Where she is right now is good for her, but as she gets bigger, she will increase her production of Hgb.  When it gets over 18mg/dl, the blood starts to get thick and sticky, prone to clotting.  So when she gets to that point, we will know that it's time for the next step.

We did find out that Natalie's left ventricle is still too small to sustain life by itself.  The normal volume that a LV of a child her size would hold around 75ml.  Hers holds about 20ml, clearly not enough to support systemic cardiac output.

So her next step will be the Fontan surgery.  We are not sure when that will be but have been told that we could wait up until a year from now to do it.