The MitraClip catheter-based mitral valve repair system appears to be safer than mitral valve repair surgery at 30 days and as effective at one year. Ted Feldman reported the results of EVEREST II (Endovascular Valve Edge-to-Edge Repair Study ) this morning at the ACC.
Feldman concluded his presentation by saying that “the MitraClip procedure is an important therapeutic option for selected patients with significant mitral regurgitation given the demonstrated safety, effectiveness and clinical benefit.”
EVEREST II was a pivotal study for the device in which 279 patients with significant mitral regurgitation (MR) and suitable anatomy were randomized on a 2:1 basis to the MitraClip (184) or surgery (95).
When asked why he tackled EVEREST II Feldman did not say: “Because it’s there.” Instead, in an ACC press release he said, “as clinicians, we have seen our patients transformed from highly symptomatic to highly functional with a catheter procedure – and without a long hospital stay or a long recovery period. The real excitement is seeing our experience with individual patients reflected in trial results in a clear way.”
The rate of major adverse events at 30 days (the trial’s primary safety endpoint) was 9.6% in the MitraClip group versus 57% in the control group, a highly significant difference (p<0.0001). In the MitraClip group there was 1 case in which a patient had a GI complication requiring surgery and there were 12 patients who received transfusions requiring 2 or more units of blood. In the control arm there were 2 deaths, 2 major strokes, 1 patient who underwent reoperation, 4 patients who had urgent CV surgery, 4 patients who required ventilation for more than 48 hours, and 42 patients who required transfusions of greater than 2 units.
At one year the clinical success rate (freedom from the combined outcome of death, MV surgery or re-operation for MV dysfunctions, or a MR score >2 at 1 year) was 72.4% in the MitraClip group versus 87.8% in the control group, which met the trial’s definition of non-inferiority. 81.5% of patients in the MitraClip group had a MR score of 2 or less, compared to 97% in the control group.
The investigators were unable to successfully implant the device in 41 of the patients randomized to the MitraClip; 86% of patients in the control group underwent MV repair.
David Kandzari sent the following comment to CardioBrief:
At the outset, EVEREST seems a positive trial, but I think there is far more that we need to understand before making the final conclusion. For example, I find it confusing to sort out whether the data should be presented as per protocol (as was emphasized) versus intention to treat. Per protocol excluded over 25% of patients included in the experimental arm, and we just don’t know what specifically happened to these patients. Apparently, the ITT analysis does not differ much from per protocol, but then again, if the procedural failures cross over to surgery, then it would make sense that the difference between the two comparator arms would be lessened. So, then the trial becomes one more of strategy than an evaluation of competing therapies, ie, do we first attempt percutaneous closure, hoping for a suitable result, and then if not, refer to surgery? This is a somewhat different clinical perspective than considering the 2 treatments exclusionary to one another. We also need to learn more about how the investigators came up with efficacy and safety boundaries. The estimate for safety was far from that observed, largely due to transfusions, and the margin for efficacy seems quite wide. I’m hopeful further presentations will clarify these issues for a very novel and exciting technology.