INTRODUCTION
Transcatheter edge-to-edge mitral valve (MV) repair with the MitraClip
system is increasingly regarded as a successful and effective
therapeutic alternative to surgical therapy for relevant refractory
mitral regurgitation (MR) in patients at high surgical risk (1), (2),
(3). The MitraClip procedure reduces the MV area and generates, at least
two new orifices, followed by an increase of the mean transmitral
pressure gradient (MG). An MG over five mmHg after clip attachment has
been shown to be associated with adverse outcomes and should thus be
avoided according to the current guidelines (4), (5). On the contrary,
some recent studies found no predictive value of MG for clinical
outcomes after interventional therapy for functional MR (6), (7).
MG is assessed by transesophageal echocardiography using the MV
peak-systolic velocity from intraprocedural continuous-wave Doppler
measurements. Intraprocedural assessment of MG can be influenced by
various factors: heart rate and rhythm, hemodynamics during general
anaesthesia and presence of inotropes, as well as measurement-related
factors, such as angulation errors. Furthermore, there are additional
heart-related factors: (i) left-atrial compliance, (ii) left-ventricular
end-diastolic pressure, and (iii) valvular parameters (8), (9), (10).
Therefore, intraprocedural MG should be carefully and individually
anticipated, since the cofactors mentioned are dynamic and time-varying
parameters and might lead to over-or underestimation of MG. Taken
together, it is unknown how much the intraprocedurally measured MG
values change following general anaesthesia and restoration of ”normal”
hemodynamic conditions or following epithelialisation of the clip
devices.
We, therefore, aimed to a) evaluate the dynamic changes of MG, both
peri-interventionally and during the follow-up (FU), b) assess the
impact of periinterventionally measured MG on clinical outcomes, and c)
analyse predictors for unfavourable MG after MitraClip.