Page 776 - Read Online

Page 2 of 14 Stolz et al. Mini-invasive Surg 2020;4:76 I http://dx.doi.org/10.20517/2574-1225.2020.69

comorbidities, mitral valve anatomy, as well as left and right heart function can provide detailed prognostic value
regarding acute procedural success and long-term survival.

Keywords: MitraClip, transcatheter mitral valve edge-to-edge repair, predictors for mortality, secondary mitral
regurgitation, primary mitral regurgitation, heart failure, percutaneous mitral valve repair

INTRODUCTION
Mitral regurgitation (MR) is a major contributor to cardiovascular morbidity and mortality in patients with
[1-3]
heart failure . With more than ten years of clinical experience and continuous technical development,
transcatheter mitral valve edge-to-edge repair (TMVr) is a well-established treatment option for patients
suffering from primary (PMR) or secondary (SMR) mitral regurgitation. In PMR patients, structural
damage of different parts of the valvular apparatus itself can lead to development of MR, while SMR is
[4]
caused by atrial and ventricular pathologies . Accordingly, PMR and SMR themselves form heterogeneous
groups and can occur in combination, a fact which must be taken into account for therapeutic decisions
[5]
and device selection . In PMR, TMVr is recommended in case of prohibitive surgical risk and absence of
adverse anatomic features, based on the results of the EVEREST (Endovascular Valve Edge-to-Edge Repair
[6-8]
Study) trials . For SMR, the 2020 Focused Update of the 2017 ACC Expert Consensus Decision Pathway
on the Management of Mitral Regurgitation does not include surgical ineligibility as a primary criterium
for TMVr usage. TMVr can be the therapy of choice for severe SMR with left ventricular ejection fraction
(LV-EF) between 20% to 50%, left ventricular end diastolic diameter (LV-EDD) < 7.0 cm, and persistence
of clinical signs and symptoms of heart failure despite of optimal guideline-recommended medical
treatment (GDMT) and, if applicable, cardiac resynchronization therapy [8-11] . These recommendations are
based on two large randomized-controlled trials (Cardiovascular Outcomes Assessment of the MitraClip
Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation - COAPT and
Multicentre Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary
Mitral Regurgitation - MITRA-FR), which revealed different findings regarding the prognostic benefit
of TMVr treatment on top of GDMT in SMR patients [12,13] . Recently, several theories have been proposed
to deliver potential explanations for these varying results [14-19] . Undoubtedly, patient selection for TMVr
could be a crucial factor influencing not only clinical outcome but also procedural success. The influence
of cardiac anatomic parameters on outcome after TMVr is less understood, but has gained recent attention
[20]
to optimize procedural and clinical results . In this review, we evaluate the current data on the impact of
anatomical and functional left and right heart features, as well as clinical parameters and comorbidities on
acute procedural success/failure and mortality after TMVr.

ENDPOINTS AND PATIENT COHORT
The two common endpoints in outcome analysis after TMVr that this article focuses on are acute
procedural failure (APF) and all-cause and/or cardiac mortality [21-24] . The Mitral Valve Academic Research
[24]
Consortium (MVARC) differentiates between technical, device, procedural, and patient success . In
other words, APF is the absence of procedural success, which consists of technical success at exit from the
[24]
catheterization laboratory, absence of procedural mortality or stroke, and reduction to MR 2+ or lower .
Clearly, reasons for APF could be inability of device implantation due to individual anatomical features
or generation of significant mitral valve stenosis represented by increasing mean mitral valve pressure
gradients (MV mean PG). MVARC recommends postprocedural MV mean PG not to exceed 5 mmHg .
[24]
Secondly, APF can be caused by insufficient MR reduction despite successful implantation of the device.
According to MVARC criteria, procedural results are defined as optimal in case of absent or trace
[24]
postprocedural MR .