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Valve Replacement & Repair
Transcatheter Mitral Valve Repair – Challenges and Opportunities
a report by
Francesco Maisano, Antonio Colombo and Ottavio Alfieri
San Raffaele Scientific Institute and University Hospital, Milan, Italy
Catheter-based interventions for mitral regurgitation are currently under pure mitral stenosis is reserved for patients with more advanced disease
clinical evaluation. They represent the natural evolution of surgical and with more calcified valves.
4
The history of mitral balloon valvuloplasty
treatment, which has been characterised by a progressive decline of suggests that similar issues should be expected for the upcoming mitral
invasiveness from the traditional open-heart and open-chest procedures repair transcatheter techniques. Although catheter-based mitral repair
to minimally invasive video-assisted procedures (including robotic has been surrounded by scepticism, the development of more reliable
technology), with closed-heart solutions using the catheter-based and simpler techniques and the narrowing of indications will probably
approach being the last stage of this process. The new devices are allow transcatheter interventions to compete with surgery.
pushing transcatheter intervention beyond the limit of balloon
valvuloplasty for rheumatic mitral stenosis. As happened several years Techniques and Devices
ago during the pioneering phase of balloon mitral dilatation, Several technologies and techniques, mostly derived from surgical
transcatheter mitral repair is encountering numerous challenges, procedures, are currently being evaluated in pre-clinical research and
although an entire world of opportunities can be foreseen. clinical trials. Two main families of techniques are available: mitral valve
annuloplasty and leaflet repair (using the Alfieri technique
5
).
Is There a Need for New Mitral Valve Treatment Solutions?
The need for less invasive solutions to treat mitral regurgitation arises The device with the largest amount of clinical experience is the e-valve
from a recent report from the EuroHeart survey revealing that a Mitraclip™, which is in a phase II US Food and Drug Administration (FDA)
significant proportion of patients with severe mitral regurgitation are clinical trial – Efficacy of Vasopressin Antagonism in Heart Failure Outcome
currently not referred for surgical treatment.
1
Elderly patients, particularly Study with Tolvaptan (EVEREST) II. Since its first in-man case in 2003,
those with co-morbidities and with low ejection fraction, are the most approximately 150 patients have received mitral repair with this device. The
likely to be refused surgery. Transcatheter interventions could be a Mitraclip is a clip device that is intended to replicate surgical edge-to-edge
solution for these challenging patients, and may increase the proportion repair in an endovascular fashion. Leaflet approximation is obtained with
of patients undergoing mitral valve treatment. At the opposite end of the either one or two clips. The procedure is completed by a combination of
spectrum, less invasive solutions may be more acceptable for younger fluoro and echo guidance. Imaging is the most challenging issue during this
patients who are referred for early treatment. procedure. While fluoroscopic imaging is irreplaceable during the initial
steps of the procedure (guidewire manipulations, transeptal puncture and
What Can We Expect in the Future? Learning from the positioning of the delivery system in the left atrium), echocardiography is
Experience of Balloon Valvuloplasty used to guide leaflet capture and to confirm the efficacy of the clip position
Mitral balloon valvuloplasty was introduced about 25 years ago by the before the final delivery. The initial results of the EVEREST trial show that
surgeon Kanji Inoue.
2
The concept of balloon dilatation was derived via isolated transcatheter edge-to-edge using the Mitraclip device is feasible,
the surgical closed commissurotomy, and the specific indications still and that in selected patients mitral regurgitation can be eliminated or
reflect this lineage. The initial clinical experience in the late 1980s was largely reduced. In addition, the procedure seems to be particularly safe,
characterised by a substantial incidence of procedural complications. with the incidence of peri-operative morbidity and mortality below the
Contemporary surgical literature includes many case reports of life-saving average in surgical data.
6
It must be clarified, however, that patients
emergency operations required to treat acute mitral regurgitation due to undergoing isolated transcatheter edge-to-edge are highly selected.
balloon lacerations.
3
As more experience was accumulated, indications Surgical experience has demonstrated that isolated edge-to-edge without
were identified, and patient selection has been perfected. Today, acute annuloplasty carries a higher risk of late recurrence of mitral regurgitation
complications of mitral balloon valvuloplasty are rare, and surgery for and need for further interventions.
7
The only exception is those few
patients who are referred to surgery with minimal annular dilatation.
8
Annular dilatation has never been a selection criterion for repair in surgical
Antonio Colombo is Director of the Catheterisation
Laboratory at the EMO Centro Cuore Columbus in Milan,
series. Surgery is usually carried out with the routine addition of
and also works at the San Raffaele Scientific Institute. He
annuloplasty, regardless of annular dimensions and function. In the
pioneered the concept of adequate stent deployment
endovascular scenario, assessment of annular function and dimensions will
during coronary interventions, and defined the role of
intravascular ultrasound in this setting. Dr Colombo play a major role in the selection process for the different procedures.
9
obtained his MD from the University of Milan, School of
Medicine in 1975.
In the field of annuloplasty, the device with the largest amount of experience
E: colombo@emocolumbus.it
is the MONARC™ device (Edwards Lifesciences LLC, Irvine, CA, US), which
has been used in over 50 implants. The MONARC device is a coronary sinus
66 © TOUCH BRIEFINGS 2007
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