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Page 4 of 12 Cepas-Guillen et al. Vessel Plus 2021;5:26 https://dx.doi.org/10.20517/2574-1209.2020.79

[20]
Administration in USA in 2013 . The device itself consists of a polyester-covered cobalt-chromium two-
armed clip [Figure 2]. The latest generation of MitraClip® (G4) has four size options: two length options of
NT (short-arm) and XT (long-arm) and two width sizes of Regular and W (wide). In addition, the G4 has
an independent grasping. The NT device has the following characteristics: clip length of 15 mm, grasping
width of 17 mm, and arm length of 9 mm. The XT device has a longer arm compared to the NT. The XT has
a closed clip length of 18 mm, a grasping width of 22 mm, and arm length of 12 mm. On the other hand, the
W family is 1.5× wider than the regular clip, providing a larger grasping width for both NT and XT options.
The different clip options may enable easier and quicker leaflet grasping, reduce the number of clips
required, and expand percutaneous treatment to patients with less favorable anatomies [21,22] .

The EVEREST 2 trial was published more than 10 years ago and represented the most important trial for
the therapy implementation at its early stage. The trial compared surgical and percutaneous MR treatment
in high-risk patients, demonstrating that the MitraClip® system was safe and effective for this high-risk
population. The primary effectiveness outcome at one year (intention-to-treat), defined as freedom from
death, mitral valve surgery (in the percutaneous group), or reoperation (in the surgical group), or 3+ to 4+
mitral regurgitation occurred in 55% of the percutaneous group vs. 73% of the surgical group (P = 0.007).
Rates of death were 6% vs. 6%, surgery for mitral valve dysfunction was 20% vs. 2.2%, and 3+ to 4+ mitral
regurgitation was 21% vs. 20%, respectively, for percutaneous vs. surgical groups. In a per-protocol analysis,
freedom from the primary outcome at one year occurred in 72% vs. 88% (P = 0.02), respectively. The
primary effectiveness outcome at 2 years (intention-to-treat) occurred in 52% vs. 66% (P = 0.04),
respectively. The primary effectiveness outcome at 5 years occurred in 44% vs. 64% (P = 0.003), respectively.

In addition, the trial defined which specific MV anatomies were more appropriate for achieving favorable
[23]
results with the therapy . Nonetheless, with increasing experience, MitraClip® can be successfully
implanted in patients with a more complex MV anatomy. Table 1 shows the optimal, suboptimal, and
prohibitive anatomies for MV repair with the MitraClip® system and extensively with any percutaneous
edge-to-edge repair system .
[24]

More recently, two important randomized trials, MITRA-FR and COAPT helped to understand the
treatment of patients with FMR [25,26] . In COAPT, FMR correction with the MitraClip® system was associated
with lower mortality and heart failure admissions compared to optimal medical therapy while this was not
observed in MITRA-FR. Selection of patients with more severe MR and less dilated LV seemed to be the
factor linked to better outcomes compared to medical therapy.

Procedure description
General anesthesia and transesophageal echocardiographic (TEE) guidance are required. The device is
introduced via a 24 French orientable guiding catheter from the femoral vein through transeptal access to
the left atrium. The transseptal puncture should be posterior and superior to the fossa ovalis to allow at least
3.5 cm of height to deliver the MitraClip® device adequately. Heparin is administered to achieve an activated
[22]
clotting time over 250 s . The clip delivery system is advanced through the steerable guide catheter, and the
clip is positioned in the site of the most severe MR jet with echocardiographic guidance. At this moment,
correct orientation of the clip arms is pursued. Once optimal coaxially is achieved, the clip is then advanced
inferior to the valve plane and retracted with the arms extended in order to capture the anterior and
posterior MV leaflets at the location of the MR jet. The degree of MR and the measurement of trans-mitral
gradients are then evaluated while the clip is in place, but before release of the device from the delivery
[27]
system. If the result is correct, then the clip is released from the guide catheter . Repeat hemodynamic,
angiographic, and echocardiographic assessments are performed to confirm a successful result. Additional