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.