I also had a great deal of leaking at my one year follow-up. This past June I had a second device placed and it has made a world of difference for me. They did not remove the first device (that can only be done with open heart procedure). Just a little background for you: May 2009 had a 25 mm Gore-Helix device placed. At my 3 month and 6 month checkups substantial (5+) flow was seen across the device. Since I am an insulin dependent diabetic, we decided to wait until a year post procedure to do another bubble study. At one year, I was still at a 5 with significant symptoms. I opted to have another procedure to determine where the leak occurred and to place a second device. Once in there, the doc found three areas where blood (and bubbles/clots) were passing through my device. He was able to use a 10mm vascular plug to close off all three of these areas.
Best of luck to you and your search for some answers. I was very upset (as I imagine you are) to find out my device had not completely worked. Please let me know if you have any questions. There are not many of us that have had this happen (or at least that's what I've seen). I am greatful that I followed my gut instinct and went back for the second procedure.