Effects of Percutaneous MitraClip Implantation On Atrial Septum and Mitral Inflow Patterns During Exercise

Due to the implantation of one or more MitraClips in patients with mitral valve
regurgitation (MR), a decrease in mitral valve area (MVA) is created, which has
not been shown to result in clinical significant mitral stenosis. However
mitral inflow patterns were only measured in these patients during resting
conditions. Mitral inflow patterns were measured during exercise in patients
treated by the surgical double-orifice technique of Alfieri and increased
significantly during exercise but stayed within the upper reference limits.
Therefore we would like to investigate the effect of MitraClip implantation on
mitral inflow patterns after exercise.

Over the last decades, there has been renewed interest in the use of the
transseptal (TS) approach during treatment of heart diseases. As the number of
TS procedures grows and the diameter of puncture devices increases, there is
concern for an increased prevalence of persistent iatrogenic atrial septal
defects (iASDs). The iASD has been reported as a complication of TS puncture
performed in different types of cardiological procedures. Paradoxical embolism
resulting in a transient ischemic attack (TIA), acquired cyanotic heart disease
and right ventricular failure has been reported in patients with an iASD. In a
previous study iASD has been shown to persist beyond 9 months in 30% of
patients undergoing pulmonary vein isolation4. Current studies assessing the
incidence of iASDs after TS catheterization suggest that the majority of iASDs
close by 6 months. However, these data were largely obtained after TS puncture
using 8F sheaths.
The sheath used with MitraClip implantation is one of the largest TS puncture
devices, with a diameter of 24F. Until now the persistence and possible risk
of an iASD created during MitraClip implantation is not known. Therefore we
would like to investigate the prevalence, persistence and risk factors
associated with the iASD in MitraClip patients.

To evaluate the effects of MitraClip implantation on:
* mitral inflow patterns during exercise
* the atrial septum, moreover the persistence of the iatrogenic atrial septal
defect and the consequential risk of right atrial and ventricular dilatation
and paradoxal embolism.

In this single center study we would like to include at least 30 patients who
underwent MitraClip implantation with placement of one or more clips in our
institution between May 2009 and February 2012. As this is an exploratory
study, no formal sample size calculation can be made.

Participants will have no direct benefit from the study itself, although the
echocardiography by high-level investigators may reveal potential valve- or
atrial septum related problems which may be corrected at an early stage. The
benefit of this study consists of the knowledge the investigators can gain from
this study about the effects on mitral inflow patterns and the atrial septum
after MitraClip implantation. The possible risks that participants are exposed
to are minor; an intravenous cannula is needed for contrast for ASD
measurements.