Thanks friends !
Yes Wilma is my wife (already for 19 years....jeez time flies !

).
I normally don't mention it too often because I don't want to "patientice" the little guy if you know what I mean. He was doing really well in every day life but was getting some problems when he was playing football or running around with the other kids or even playing very intensely. He was born with 3 heart defects and had surgery to fix it when he was 3 months old, so we already had experience with it, but of course you never get used to it (luckily !).
For those interested I'll try to explain. Take a look at this pick while reading:

The 3 defects were:
1) missing Pulmonary valve and main pulmonary artery
2) VSD which means a hole between the left and right ventricles (which was actually a good thing to happen in the very beginning, else his blood would have no way to go right after his birth because of defect 1)
3) Mapca's. Mother nature had tried to "solve" the problem by growing 3 bypasses from the aorta to the pulmonary arteries.
This all resulted in blood flowing through his lungs and body, but oxygen rich and deoxenated blood was mixing which obviously is not what you want to happen.
When he was 3 months, they closed the VSD (problem 2). This is already a pretty "easy" surgery because it's a "common" heart defect. They made an opening in the right ventricle and placed a valve and connected pulmonary artery (which comes from a calf ! But it's "dead" so sort of like a piece of leather) and connected it to the first left and right pulmonary artery branches.
Because this way the correct situation was restored they had to close the mapca's (bypasses) of course because they are not meant to be there in the first place.
All went well then, but the valve didn't work very well in the beginning and had lost all of it's function in the end. Also the artery was a little bit narrowing. This resulted that the right ventricle had to pump much harder than normally. And then the same thing happens as when you're going to exercise a muscle: it will grow. Nice for muscles but in this case, the space in the right ventricle reduces because of this, so less blood getting in there, and again more power needed by the heart to pump the blood away.
This was all not to bad for his first years, but as mentioned, now was the time to replace it.
So a week ago they replaced that valve and artery by a larger one (again from a calf). This will hopefully last for a good number of years. It's never exact science so they can't exactly say how long. The size of the artery he has now is that of an adult.
It will not last forever so we know he will have to have this replaced every so many years (let's say, 10 years).
The good news is that next time he will not have to undergo open heart surgery, because then he will have grown enough so that they can do it by catheter, so with a small tube running from his lower belly. Of course this is a lot less exhausting for a patient. They also will be using a human donor "part" then instead of from a calf. (So everybody, become a donor ! Too many people are waiting for donor parts and there actually are people dying because of this !!!!)
Sorry for all the medical terms, but it's hard to translate otherwise.
It's in these situations that you are extremely grateful to live in a country with one of the best medical facilities in the world, plus a good and affordable (still !) health care insurance. (Not making any political statements here, but we Dutch have a habit of complaining about our country, when in fact things are pretty well organized here)
The credits of the design of the site goes to Apple because I made it within an hour with iWeb which comes standard with every Mac
