mutliple valve replacement operation

Hi guys,
I was born with heart defects, and because of this am lining up for my 6th open heart surgery operation at aged 28.  I have had my pulmonary valve replaced twice before, but this time I am supposed to get both the pulmonary and aorta valves replaced.  I guess i am a little (lot) scared about it as I feel I have just entered a phase where I have a lot of living yet to do and really don't want this to end me now.

I am just wondering if anyone out there knows how big the risk is for an operation like this?  Do many of these operations happen?  Because i have had a few operations before, does that greatly increase my risk this time (due to scar tissue around the heart)?  I live in Australia and my specialist here gave me the talk of it being a high risk operation, etc. but he is only very young and actually quite slack (When he gave me that talk, I was supposed to be seeing him so he could let me know a date for my operation... I later found out he hadn't even sent his referral letter to the surgeon yet, so figure that this "chat" was a time filler and may be a load of crock).  The surgeons office however seems a lot more positive about the operation.

Can anyone lend me some help on this matter?
Cheers
Dan