OK. Well, I haven't gone down to see Gavin yet, but I wanted to do some Google-ing first. I now have a few more questions to ask the doctor and a few more worries--as Google-ing is wont to create. The ER doctor mentioned stress to Gavin's biscuspid valve, for example, and I need to follow up asking about that. It is good to be informed. Most of what I read, has been exactly what I've been told on this end. But the info helps me process all of this. The two websites I found helpful are: http://www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/coarctation.htm and http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI=/healthatoz/Atoz/ency/coarctation_of_the_aorta.jsp
There is a picture on the first one.
The purple area indicates the place where Gavin's coartaction is located. It sounds like he's pretty much a textbook case. Very treatable, though recurrence is quite possible, which is also very treatable.