Hi Ruth,
Sorry I'm late. I typed too much and injured my arm, so had to take a break.

re menagerie: law of the jungle - big animals eat smaller animals/birds.
I have troulbe with that. If a cat eats a mouse, OK, but if it eats a bird, not
ok.
If a dog eats a squirrel, okay, sort of, but not okay if it eats a cat.
See what I mean? I don't make sense.
I still enjoy hearing about your menagerie.

I only know of a few who've had heart surgery, so I'm not a good one to ask.
Apparently there's 2 types of valves, explained here
<
http://www.sts.org/sections/patientinformation/valvesurgery/aorticvalve/index.html

mechanical valves and biological valves.
Under "risks" they don't mention previous heart surgery or the hospital.

This UK web page does
http://heartsurgery.healthcarecommission.org.uk/about-aortic-valve.aspx
If I click on any of the hospitals, it gives info specific to that hospital.
It also gives a general blurb, which appears on each hospital's page.
As folows:

Statistics calculated from patients being treated for the first time.

Factors such as ill health, increased age and lifestyle can affect a patient's
chance of surviving a major operation. When we calculate the expected rates of
survival we take these risk factors into account. Find out more about how
expected rates of survival are calculated.

What is the expected survival rate?

Factors such as ill health, increased age and lifestyle can affect a patient's
chance of surviving a major operation. Examples of things that increase the risk
of not surviving a heart operation are whether a patient has had heart surgery
before or whether a patient has long term lung disease. When we calculate the
expected rates of survival we take these risk factors into account The expected
range of rates of survival shown in the white bars on each graph above reflects
the overall risk of patients treated at the hospital. Some hospitals treat more
high-risk patients than others and as a consequence of this the average expected
survival rate for these hospitals is lower than other hospitals.

The main way of taking risk factors into account when calculating the expected
rate of survival is by using what is known as the EuroSCORE method. This is a
method of predicting the chances of dying during or within 30 days after
undergoing heart surgery. This scoring system was based on information from many
patients across hospitals in 8 European countries. In the last four years, heart
surgery in the UK has tended to be better than EuroSCORE predicts so we have
also calculated the expected rates of survival by making an adjustment to the
scoring based on the current UK only information. The adjustment for UK
performance means that more people are expected to survive and is therefore a
tougher comparison. Click on the links above to see the different expected
survival rates.

More information about how the expected rates of survival are calculated is
included in about this site.
Data Quality

The data in this unit are 84% complete. View this in comparison with other
units.
How is the survival rate measured?

This records the number of patients who survive the operation for at least 30
days after surgery and are successfully discharged from hospital afterwards.
---------------------------------------------------------------------------------

It doesn't say anything about (risks of) one type of valve vs the other.
Some Americans say to go to hospitals that have done many of the XXXX procedure
(XXX being whatever procedure).
The downside is if it's farther away, for friends or relatives to visit , or go
back and forth for rehab and rechecks.

I guess I would ask such hospitals/surgeons:
How many have you done this year and last year?  And will you be doing the
surgery or supervising the surgery?
What's your rate of short term success (alive 30 days later) and long-term
(alive 2 or more years later?
Which value are you planning to use. Please show me. And tell me the advantages
over other ones or why one is better for me than some of the others.
Have you done people with my risk factors? (and discuss them).
Is there a better time (of year) to have such surgery? (re: concern about
infections, pneumonia in hospitals)

It's not unreasonable for you to ask questions before deciding which
surgeon/hospital will do the surgery.
Lots of heart surgeries are done every year.  Most turn out very good.
Best of luck. Let us know before you go, so we can cross our fingers, light
candles, send prayers and good wishes.
Hugs
J