It depends on how you define "big improvement". For one person, this meant an improvement in her FEV1 of about 10 points and not needing as much 02 as she had had to use before. She used the improvement in her breathing and 02 usage to exercise harder, with more intensity and is now able to sit comfortably without 02 and is finding many activities much easier. She still uses her 02 most of the time, but is able to do more and with greater comfort. For her it's a big improvement.

There have been other people who have seen greater increases in FEV1 numbers, and a corresponding increase in their ability to complete daily living activities much easier. Some have gotten off 02 completely. There have been a few people who have had what they and their docs consider to be "big improvements", but what that actually means really depends on how debilitated they were prior to the procedure and their personal circumstances. In general, results have been positive, and once you are through the initial placing of the valves most people have seen some positive results. There are those who saw no improvement or coughed the valves out and some peoples who've had them removed.

We've learned a lot about what conditions produce good results, but we're clearly not at a point where we know enough about individual differences to be able to accurately predict what the results will be.