I believe that they would reduce the number of surgical procedure as much as possible because each episode would present another risk associated with the surgery itself and the anaesthetic. There is no reason why all the surgery cannot be performed in one go unless complications arise and the procedure is aborted.
Hi--
Here is our family's experiences. My Dad (who is now 84 years old) had open heart surgery in July 2008; they did a triple bypass, replaced his aortic valve, and repaired a thoracic aneurysm in the one surgery. He also had congestive heart failure before the surgery and suffers from chronic atrial fibrillation. He got through the surgery OK, though he was in the Intensive Care Unit a few days longer than they had expected, which was scary. He also has diabetes (which hasn't been under the best control over the years) and the doctors said the surgery was hard on his kidneys.