1.5 Ventricle Repair for Pulmonary Atresia?

I'm 19 and I was born with Pulmonary Atresia. I've had 3 open heart surgeries, including BT Shunt, Glenn procedure, and pulmonary valve replacement.  I believe the BT Shunt was shut down in a later surgery.
Currently, I am scheduled to have my 4th open heart surgery on January 14.  My surgeon is planning to do what is called a "one and a half ventricle repair".  When I asked him what the survival rate was, he hesitated then said, "In my hands?  I'd say its a 98% chance you'll make it out."  His hesitation worried me, and I looked up some information online, but most of it was very hard to understand, but I did not get a good feeling out of it.  However, my mother said she researched the procedure and said that it had an "excellent success rate".
Does anyone have any experience with this procedure or any knowledge about the survival and success rates?  I am really nervous.
Thanks.