Percutaneous Mitral Valve Repair
Percutaneous mitral valve repair using the MitraClip (Abbott
Laboratories, Menlo Park, California, USA) has been approved in 2008 in
Europe and 2013 in the United States. Is one of the most common
procedures performed today for patients with primary severe mitral
regurgitation (MR) who are deemed unfit for surgery. This is usually the
case for older patients with multiple co-morbidities.7,
27-31
The MitraClip device has 2 essential components: the clip delivery
system and a guide catheter.30 It enters the
circulation through the femoral vein and is directed towards the heart.
Transseptal puncture allows the advancement of the MitraClip to the left
atrium. Moving through the mitral valve (MV), the apparatus reaches the
left ventricle. The clip will grasp the leaflets, bringing them
together, connecting the middle segment of the anterior leaflet to the
one of the posterior leaflet. The MitraClip technology is based on
Alfieri’s surgical technique, thus creating a ‘double orifice’ MV.
Before releasing the clip, assessment of the procedure via
transesophageal echocardiogram (TEE) is required, as the MitraClip can
be reopened and repositioned. This step also allows re-evaluation of
mitral valve defect (if still present) and
re-grading.27,30-32
After the operation, patients receive clopidogrel for 30 days and
aspirin for the next 6 to12 months.27 Procedural
success is highly dependent on patient factors. TEE along with
transthoracic echocardiography is used for patient screening and ensures
that anatomic requirements are met for a feasible MitraClip repair.
Calcification of more than 80% of leaflet area, short leaflets, and low
baseline MV area are common disqualifiers from the procedure, while
orifice area greater than 70.8 mm2 or mitral valve
area less than 3 cm2 were indicators of clip
failure.33
Although considered safer than surgical treatment for severe primary MR,
percutaneous repair still has its risks. Common postoperative
complications include atrial fibrillation and acute kidney injury, as
well as partial detachment of the clip. Mitral stenosis or full
displacement of the clip have occurred in less than 5% of cases. The
EVEREST II trial, which proved the efficacy of MitraClip in 2010 and
gained its approval in the US, also highlighted that nearly 20% of
patients needed another operation within a year.27,32
Since 2019, the MitraClip has been approved in the USA for secondary
functional MR as well.27 Ongoing clinical trials in
Europe (RESHAPE-HF2) and Canada (EVOLVE-MR) are considering the
effectiveness of promoting this treatment for functional MR, after
another two anticipated clinical trials, COAPT and MITRA-FR, had
conflicting results (mainly due to different selection
criteria).34-36 Cardioband (Edwards Lifesciences,
Irvine, California) percutaneous annuloplasty procedure is currently
used in Europe for the treatment of this condition.33
Nevertheless, the first line of management of secondary MR remains
pharmacological therapy: angiotensin-converting enzyme inhibitors,
beta-blockers, and diuretics, providing symptom
relief.37 Tsang et al. paper on recent advances in the
management of mitral valve disease argued that doctors are more reticent
in offering interventional therapy such as mitral valve repair or
replacement, in the absence of clear guidelines (in the US, replacement
is still favored, sparing the sub-valvular apparatus, while in Europe
repair is considered first). This could adversely affect outcomes for
patients.13 Case studies are expected to be published
in the coming years (especially from the USA) and careful documentation
of medical decisions and considerations would be advisable. Over time,
the conduction of longitudinal studies should also shed some light on
the issue.
PASCAL Transcatheter mitral valve repair system is a newer device that
is used for percutaneous repair of MR. It hopes to fill in the gap left
by the MitraClip and help patients who do not meet the anatomic criteria
for the procedure. PASCAL is still developing, although an initial
clinical trial including 23 patients has yielded favourable results. The
CLASP study was shortly commenced, which gained CE marking approval
after 98% out of the 62 patients had an MR grade of two or under at 6
months follow-up. More randomized controlled trials are needed before
the procedure becomes widely available.13,38,39