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Scotti et al. Mini-invasive Surg 2020;4:49 I http://dx.doi.org/10.20517/2574-1225.2020.38 Page 7 of 9

timing of intervention. On the contrary, limited data are available regarding advanced HF patients who
are excluded from randomized clinical trials and for which the only available evidence derives from
observational studies.

Clinical evidence
We can identify the following strategies in performing percutaneous mitral valve repair in advanced HF
patients [Figure 1]:
1. Bridge to heart transplantation (BTT)
2. Bridge to HTx candidacy (BTC)
3. Bridge to recovery (BTR)

[24]
One of the first papers on MitraClip procedure, reported by Franzen et al. in 2011, showed for the first
time that MitraClip implantation was safe and significantly improved the New York Heart Association
(NYHA) class of patients with end-stage/advanced HF, especially of those who had significant reduction
of MR grade after the procedure. In 2015, Garatti and colleagues described a case report in which the
[26]
[25]
percutaneous mitral valve repair was effective as a BTT . Similarly, Sankar et al. implanted a MitraClip
and a Carillon device (Cardiac Dimensions, Kirkland, WA, USA) in the same patient with the aim of BTT,
[27]
replicating the surgical counterpart known as “Alfieri technique” . In a larger cohort of 75 advanced
HF patients, the following were observed: symptoms improvement, re-hospitalizations reduction and
lower pro-BNP levels after percutaneous mitral valve repair with MitraClip, despite the lack of LV reverse
[28]
remodeling .

[29]
Further evidence derives from a German proof of concept case series showing that MitraClip is not
only feasible in advanced HF patients listed for HTx, but also leads to favorable hemodynamic effects such
[30]
as lower pulmonary artery pressures. Similar results were described by an Italian group in which the
reduction of pulmonary vascular resistances led to the absence of further hospital admissions for HF and
reclassification of these patients who became eligible for HTx. The goal in the latter study was to make
use of the percutaneous device as BTC. Another report published in 2017 proved that the MitraClip can
promote such a benefit as leading to HTx delisting following an optimal clinical and echocardiographic
[31]
recovery : an initial BTT strategy turned into a BTR.

MitraBridge study registry
The ongoing “MitraBridge” registry, presented at EuroPCR 2019, was conducted with the aim of better
[32]
understanding the outcome after MitraClip in this extreme setting of patients . This international,
multicenter registry collected data for nearly 100 end-stage HF patients treated with the percutaneous
device as bridge strategy. Baseline characteristics were clearly different from those belonging to MITRA-
FR and COAPT populations: despite a younger age [57.5 years (50-63), median and interquartile range],
there were reported lower values of mean ejection fraction (27%), higher percentage of NYHA Classes III-
2
IV (96%), higher mean left ventricular end diastolic volumes indexed (134 mL/m ), elevated mean systolic
pulmonary artery pressures (sPAP, 51 mmHg) and mean pulmonary capillary wedge pressures (25 mmHg)
and the majority (43%) had an INTERMACS profile of 5-6. At 1 year, two thirds of the cases achieved a
primary composite endpoint of elective HTx, entering (or remaining) in HTx list and delisting for clinical
improvement; the rest of the patients who did not reach those events were death, implanted with LVAD,
transplanted urgently or still waiting for HTx listing. The patients who were delisted exhibited significant
clinical improvement represented by marked reductions in NYHA class, sPAP and MR grade, which
allowed a BTR.

At present, there is still little knowledge about the real effectiveness and applicability of the MitraClip
procedure in the case of advanced HF. Although this procedure is almost ineffective for some of the patients