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Stolz et al. Mini-invasive Surg 2020;4:76 I http://dx.doi.org/10.20517/2574-1225.2020.69 Page 7 of 14

Table 2. Mitral valve: predictors for all-cause mortality after TMVr for MR
Parameter Cut-off MR etiology Ref.
MV mean PG (pre) > 1.5 mmHg SMR/PMR [27]
* SMR/PMR [34,36]
MV mean PG (post) > 5 mmHg (invasive) SMR/PMR [55]
> 4.4 mmHg (echo) SMR/PMR [55]
Acute procedural failure **** SMR/PMR [57,76,87]
Residual MR ≥ 2+ SMR [33]
≥ 2+ SMR*** [49]
≥ 3+ SMR [33]
≥ 2+ SMR/PMR [32,58]
≥ 3+ SMR/PMR [59]
* SMR/PMR [25,34,36,56]
* SMR/PMR*** [44]
MR recurrence < 2 years ≥ 2+ SMR/PMR [35]
VCA (post) > 25 mm 2 SMR [62]
Previous MV surgery ** SMR/PMR [56]

*Continuous parameter; **binary parameter; ***cardiac death; ****operator-reported failure, conversion to surgery, abortion of procedure
or severe residual mitral regurgitation. TMVr: transcatheter mitral valve edge-to-edge repair; MR: mitral regurgitation; SMR: secondary
mitral regurgitation; PMR: primary mitral regurgitation; PG: pressure gradient; VCA: vena contracta area; MV: mitral valve

[62]
associated with worse long-term outcome . Mitral valve anatomy itself seems to play a minor role in
predicting long-term mortality after TMVr [Table 2]. The only MV configuration that impairs outcome in
terms of higher MR severity at follow-up examination seems to be restricted posterior mitral valve leaflet
motion defined as posterior mitral valve leaflet tethering angle > 45° . Whether posterior mitral valve
[63]
leaflet tethering impacts not only procedural success but also long-term mortality has not been shown so
far.

The prognostic role of ischemic origin of SMR has been studied by several groups. Apparently, predictors
[64]
for all-cause mortality could be different in ischemic versus non-ischemic SMR . Tricuspid annular
plane excursion, renal failure, diabetes mellitus, previous heart surgery, and coronary artery bypass graft
[64]
are predictive for all-cause mortality in ischemic, but not in non-ischemic SMR . Besides ischemic and
non-ischemic subgroups, SMR etiologies can be separated by LV-LA function. Among those is ASMR, as
previously mentioned [54,65,66] . While our knowledge of anatomy and pathophysiology of ASMR is growing,
specific predictors for all-cause mortality after TMVr are so far lacking .
[66]

RIGHT VENTRICULAR FUNCTION AND PULMONARY HYPERTENSION
Composed PMR and SMR patient collective
Data on right ventricular (RV) dysfunction in composed PMR/SMR collectives are absent. Nevertheless,
pulmonary hypertension has been shown to impair prognosis as it is associated with worse long-term
survival [27,67-69] . Cut-off values for systolic pulmonary artery pressure as a measurement of pulmonary
hypertension vary between 37 mmHg and 60 mmHg [Table 3].
[67]
SMR only collective
In contrast to the lack of data for PMR patients, there is a growing body of knowledge that RV dysfunction
and pulmonary hypertension in SMR patients are crucial factors for the prognosis after TMVr, pulmonary
hypertension (as expressed by elevated systolic pulmonary artery pressure) is also associated with long-
term mortality in SMR patients [Table 3] . Obviously, pulmonary hypertension due to left ventricular and
[49]
atrial dysfunction and RV function are closely linked. Presence of RV dysfunction, as expressed by impaired
tricuspid annular plane excursion or RV peak systolic velocity, leads to biventricular failure [Table 3] [47,70-72] .
Importantly, TMVr treatment is capable of improving RV function. One study found an improvement of
[73]
tricuspid annular plane excursion by 4 mm and peak systolic velocity by 4 cm/s at 6 months follow up .