Hi,
Am not sure whether there is a different limit for 'the general public' and aircrew but you may well be right. Those pressures seem to be about in the right ballpark.
Mechanical valves last longer/indefinitely/don't need replacement normally but require lifelong anticoagulation with a bloodthinning agent. Over here in the UK we would use Warfarin on the continent Sintrom/Coumarin. They are agents which interfere with the bloodclotting cascade.
Bio-valves (Pigs) wear out after a while (?10-15years) but no need for anticoagulation.
Although the idea of a heartvalve replacement is daunting and the operation a serious matter, the vast majority of people do very well following replacement surgery.
I see you are in Oz so check the implications for your medical with CASA, although I think you are correct, and obtain further, more to the case applicable information from the medics involved.
If it is about you all the best and hope all goes well, if it is for a friend you are asking wish them well.
Ciao
FD