Another valve replacement

My mother underwent valve replacement surgery two years ago.  Because she has often had problems with excessive bleeding, as well as clotting, she and her surgeon decided it would be best for her to receive a porcine valve, in lieu of a mechanical one.  She was only 55 years old at the time, so, we always knew that a second surgery would probably be necessary in another 10-15 years.  But now, only two years later, the replaced valve is leaking, and needs to be replaced a second time.  We are extremely concerned about the risks of a second surgery.  We are also concerned that the valve will fail again in another 2 years, and she'll be facing a third operation down the road.  The initial surgery was performed at Johns Hopkins, so, we all doubt that the valve failed due to some oversight on the surgeon's behalf.  Is it extremely uncommon for a porcine valve to fail after only two years, and is this going to be a highly risky or dangerous procedure?  Any advice?

Thank you!

[Darcy Green Conaway, MD]

Second surgeries are always higher risk than the original surgery as you are dealing with more scar tissue, etc. As far as the exact risks, you should discuss with the surgeons performing the surgery the risks at their institution. The only advice I have at this time is be very educated about what is going on and be willing to accept the risks if you decide to proceed with surgery.