Medical Device Daily Washington Editor
SAN FRANCISCO – Mitral valve regurgitation has long proven a tough nut to crack, but recent data from trials for developmental devices suggests that medical science is making headway on this front. Some of the trials also suggest that the effect of these fixes on congestive heart failure is discernible, leading one of the presenters to remark that the Centers for Medicare & Medicaid Services might be happy to hear about some of these data.
All the same, the FDA hurdle must be cleared first and the devices in question have not yet made that leap, although the presenters seemed optimistic on that count.
Tomasz Siminiak, MD, of the Poznan University of Medical Sciences (Poznan, Poland), discussed six-month data from the Titan trial for the Carillon mitral valve contour system, made by Cardiac Dimensions (Kirkland, Washington). This device is fixed around the mitral valve and uses tension to keep it in place while the tension forces the mitral valve into a tighter circumferential geometry, hence reducing regurgitation. Unlike most percutaneous devices, the device is intended for delivery via the jugular vein.
Reviewing six-month data from the Titan trial, Siminiak reminded the audience, which was a standing-room-only crowd, that the intended indication is for patients with severe regurgitation and a left ventricular ejection fraction of less than 30%. Inclusion criteria were New York Heart Association class II, III and IV heart failure and the primary safety endpoint was the 30-day rate of major adverse events (MAE).
The device consists of two nitinol anchors and a bridge implanted into the coronary sinus. The distal anchor is set while the catheter withdraws so as to set the proximal anchor. The procedure can be reversed and captured by the catheter up to the point of decoupling of the catheter from the proximal anchor, so a surgeon who sees a problem with anchoring can reverse and withdraw.
Siminiak noted that the Titan study enrolled 65, with 12 who flunked screening, leaving an intent-to-treat group of 53. Of this group, 36 were implanted while the other 17 were not due to "insufficient mitral regurgitation reduction," Siminiak said, and/or coronary artery compromise. Of the 53 ITT enrollees, 50 were in New York Heart Association class III heart failure, two were in class IV, and one in class II.
Siminiak said procedural safety in Titan was excellent. "The major adverse event rate of 1.9% at 30 days highlights the safety of this procedure," he said. Measures of regurgitation after six months showed that the narrowest point of the ejection stream had shrunk by roughly a third. "The volume of the jet was very small, very thin," said Siminiak, and hence improvement in regurgitation was by at least one class in all cases. He also said the "significant reduction in MR was maintained after six months" and that the data indicate a "positive effect on remodeling."
The audience seemed impressed, with one attendee characterizing the data as "very promising." As for whether any patients experienced recurrence of regurgitation, Siminiak said there was "a single patient with loss of detention" of the valve, but added that "some patients improved into reverse remodeling" of their heart failure.
Siminiak remarked that the device was not exactly as originally designed. The Carillon was originally designed with two anchors made of a pair of wires each for tension, but there was originally no twist in the anchoring wires. After several early cases indicated the initial design lacked sufficient tension in the distal anchor, the company twisted those anchor wires, and the proximal anchors wires had also been twisted by the time the sponsor started enrolling for the Titan trial.
Saibal Kar, MD, of Cedars Sinai Medical Center (Los Angeles), reviewed the Everest (Endovascular Valve Edge-to-Edge REpair STudy) trial for the MitraClip, which is indeed a clip that is placed about midway across the two leaves of the mitral valve, pinching that portion of the leaves together. Hence, the mitral valve is left with two smaller openings, and the device's placement is intra-operatively adjusted for ideal ejection volume. The product is made by Evalve (Menlo Park, California).
Kar observed that while "the effect of valve repair without annuloplasty" is not known, he remarked that the hypothesis is that "putting in a MitraClip might actually regress" congestive heart failure. Of the 78 subjects initially enrolled, 32 exhibited diastolic MR and the remainder functional MR. He noted that the estimated STS (Society of Thoracic Surgeons) score averaged 17%. "Most would agree this is a really sick population," he observed.
Kar said that the session marked the debut of data for annular dimensions. "For the first time we noticed what happens to the septal-lateral dimensions," he said, noting that for the 26 patients with one-year data, diastolic annular dimension dropped from 3.8mm to 3.6 and systolic dimension fell from 3.2mm to 3.0. As for ejection fraction (EF), he said there was "expected to be no change in EF, but impressively an improvement," from 48% to 42%.
Kar also noted that the rate of rehospitalization for symptoms of heart failure among the 26 patients followed to a year was 30%. He quipped, "I'm sure Medicare would like to see this data." Perhaps as impressive was the average regurgitation score, which dropped from 3.1 to 1.6 over 12 months.
According to a Sept. 22 company statement, the Everest echo imaging data indicate "complete fibrous encapsulation of the MitraClip device with organized, endocardial tissue growth." The statement also indicates that the device is well tolerated, with "no significant stenosis or inflammation ... observed beyond 300 days."
Mark McCarty, 703-966-3694;