Great example. Senior leadership support and understanding is incredibly helpful. You can make progress without it. But eventually it becomes very difficult to work on the system without senior leadership support.
This example is also nice in showing that lean six sigma can work. So often organizations using the buzzwords don't have success. And it helps show different organizations can take different tactics. Many people don't like having a separate "improvement" office - as it can be seen to isolate it from everyday work. I think a separate, small, office, can help push improvement (especially in the first few years).
Related: lean manufacturing resources - blog posts on six sigma - resources for improvement health care management