Studies Document Initial Steps Toward Percutaneous Mitral Valve Replacement

PARIS, France—Early data on 2 different catheter-based mitral valve therapies were presented in the same Hot Line session at EuroPCR on May 21, 2014.

Francesco Maisano, MD, of University Hospital Zurich (Zurich, Switzerland), shared findings from a multicenter feasibility study of the Cardioband device (Valtech, Paris, France), a surgical-like ring implanted percutaneously to perform direct annuloplasty.

‘Surgical-Like’ Device Reduces MR, Improves Patient Function

“The Cardioband device is implanted with a transseptal approach, working within the left atrium,” Dr. Maisano explained. “Supra-annular fixation is achieved with multiple anchors delivered individually with echo/fluoroscopic guidance. Following implantation, annular dimensions are reduced under echo guidance using an adjustment catheter.”

The single-arm, multicenter study involved 24 patients with moderate-to-severe functional mitral regurgitation (MR). All were at high risk for surgery and symptomatic despite optimal medical therapy including cardiac resynchronization therapy if indicated.

At baseline, MR grade ≥ 2+ was present in all patients, 95% were NYHA class III or IV, and 70% had LVEF less than 40%. Etiology of MR was ischemic for 60% of patients.

Implantation was successful in 100%. Due to technical issues that have subsequently been corrected, Dr. Maisano said, 2 of the treated patients (8%) did not have acute reductions of annular size or MR. Septolateral dimension decreased on average by 20%, from 36 ± 3.5 mm to 29 ± 5 mm.

At 30 days, there were 2 deaths (8%), 1 stroke (4%), 2 recurrences of MR (8%), 1 patient requiring mitral surgery (4%),  and 1 bleeding complication (4%). There were no instances of renal failure, MI, respiratory failure, or cardiac tamponade. At 6 months, 90% of the 8 patients with follow-up were MR grade ≤ 2+ and 88% were NYHA class I or II. Though 6-minute walk test results did not improve from baseline to 6 months, patients did report better functional status on the Minnesota Living with Heart Failure questionnaire (42 at baseline vs 21 at 6 months; P < .01).

“Transcatheter ‘surgical’ annuloplasty is feasible [with] safety similar to other transcatheter procedures,” Dr. Maisano concluded. “Percutaneous mitral direct annuloplasty with a surgical-like device closely reproduces surgical outcomes and has the potential to become a first-line option for patients with [functional] MR requiring intervention.”

Practical Issues Raised

Session co-chair Ted Feldman, MD, of Evanston Hospital (Evanston, IL), challenged the idea that the treatment is “surgical-like.”

“Some of your colleagues in the world of surgery insist that complete rings are necessary,” he said. Dr. Maisano replied that the band itself is much like surgical bands in use today, adding, “At many centers, this is the way surgical annuloplasty is done.”

Though the procedure has a learning curve, Dr. Maisano noted, “It is feasible, it is teachable, and it is reproducible.”

Panelist Vinayak Bapat, MBBS, of Guy’s and St. Thomas' Hospital (London, United Kingdom) asked whether there were any criteria on computed tomography (CT) that help guide patient selection. “We submit all patients to CT scanning to size the device and identify any potential risks, particularly coronary lesions. We have seen no patients with coronary lesions so far, and the problem is less critical than I was thinking [it would be] before I started this program.”

John Webb, MD, of St. Paul's Hospital (Vancouver, Canada), another panelist, questioned whether the Cardioband could potentially provide “adequate anchoring” for a transcatheter aortic valve, should repeat intervention be necessary or if there might be issues with left ventricular outflow tract (LVOT) obstruction.

“This is an incomplete ring,” Dr. Maisano said. “It’s not going to be an ideal support for a transcatheter aortic valve that’s not designed for mitral.” On the other hand, he added, it would not otherwise impair use of an aortic valve.

Tiara Safe, Feasible in First-in-Man Study

In addition, Anson Cheung, MD, of Saint Paul’s Hospital (Vancouver, Canada), presented first-in-man findings for transapical implantation of the Tiara bioprosthesis (Neovasc, Vancouver, Canada), a valve specifically designed for replacement of severely diseased mitral valves.

The D-shaped device has a nitinol-based self-expanding frame, bovine pericardium leaflets, and a full atrial skirt. Ventricular anchors fix the valve onto the fibrous trigone and posterior annulus, capturing the anterior and posterior leaflets, Dr. Cheung said. Tiara is delivered via a 32-Fr sheathless system with self-dilating tip.

Dr. Cheung described 2 successful implants in patients at prohibitive surgical risk. There were no intra-operative complications or need for transfusion. Extubation took place in the operating room, and “improvement in stroke volume and lowering of pulmonary pressure [occurred] immediately post-implant,” he reported.

While the first patient, deemed extremely high risk, died 69 days after treatment, the second had an uneventful hospital stay. At 2 months, TTE showed a well-functioning valve with no paravalvular leak, LVOT obstruction, or thrombus. Mean gradient was 3 mm Hg. The patient, previously NYHA class IV at baseline, was class II at 3 months.

“In conclusion, Tiara [implantation is] feasible and safe,” Dr. Cheung said.

 

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Sources:
1. Maisano F. Percutaneous mitral valve direct annuloplasty with a ‘surgical-like’ device multicentre feasibility trial. Presented at: EuroPCR; May 21, 2014; Paris, France.

2. Cheung A. Transapical mitral implantation of the Tiara bio-prosthesis: first-in-man implantation. Presented at: EuroPCR; May 21, 2014; Paris, France.

 

 

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