My dad, who turns 85 next month, had heart surgery (aortic valve replacement, bypass, and aneurysm repair) 2 years ago. I can't recall the exact statistics the doctors gave, but I know the chances for successfully surviving the surgery without debilitation (like pneumonia, surgical site infection, stroke, etc.) were about at least 80%, and that was taking into consideration his other medical conditions like diabetes which wasn't that well controlled.
My mom, who is 82 now, had bypass surgery in Dec. 2007. I believe the statistics the doctor gave her were about 90-95%. The cardiovascular surgeon met with us before her surgery and told us the 80-ish aged patients of his that do the best as far as maintaining their independence, etc. go to a rehab facility (extended care type) for about 4 weeks after the hospitalization for strengthening, before starting an outpatient cardiac rehabilitation exercise program. This was very helpful to know, knowing what to expect and he encouraged us to look around before the surgery for 2 or 3 possible rehab places we'd be comfortable with.
I believe many insurances will cover 2 or 3 months of outpatient cardiac rehabilitation (3x/week) in the U.S.; I know both of my parent's policies would (they had different kinds of insurance.) Studies show that people who participate in outpatient cardiac rehab programs do better in the long run.
The length of average hospitalization (assuming no complications) varies somewhat from region to region and country to country, from what I understand. Here it averages 4-7 days for bypass and I think about the same for valve replacement. My father's hospital stay was longer because he had some complications due to pre-existing kidney problems, etc. (But he's still dancing today!)
I think it's hard to predict recovery time because it depends a lot on the condition of the person as they go into surgery. If there's any possible way to build up the person nutritionally before the surgery, that's a very good idea and I would recommend it. Older people don't have a lot of reserves; plus there is a period after surgery when patients don't eat any solids and often appetite takes a while to return (days/weeks.)
If there is time, I would try to see if the person can get some physical therapy before the surgery if their heart is strong enough to take it. And then make sure that the person is started on physical therapy as soon as possible after the surgery. Also, respiratory therapy is a good idea to reduce the chance of pneumonia.
If the person undergoing the valve replacement surgery lives in his/her own residence and lives alone, I would definitely recommend a 3-4 week stay at a rehab/extended care facility if possible, and then a 2-3 month cardiac outpatient program. Some hospitals have shuttle services for cardiac rehab so you don't have to worry about driving.
Getting back to the statistics, statistics are a problem because it doesn't matter if 80 or 90% of folks do well if you or the one you love is the one that doesn't. Having heart surgery is a lot to go through at any age...Both my parents struggled with the decision of whether to have heart surgery or not. Ultimately, what helped them decide is quality of life issues; the doctors said if they did not have surgery, it would become increasingly harder for them to do the things that they wanted to do. So they decided to take the risk and thankfully, it paid off.
Hope these perspectives have been helpful.
Thanks so much for responding you have given me the information I was lookin for and the encourgement for my Mom to proceed with the surgery.
Glad I could be of help. Please keep us posted as to how things go for your Mom.