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Page 14 of 23 Ancona et al. Mini-invasive Surg 2020;4:79 I http://dx.doi.org/10.20517/2574-1225.2020.80

(2) The 3D color-Doppler vena contracta area (VCA) seems promising as it is able to overcome the limits
and the assumption of EROA-PISA evaluation [12,13] . Indeed, each jet that is deemed significant would need
to be separately analyzed for VCA, since they are often in different planes and with different orientations,
and their VCAs can be added. It must be remembered that 3D color Doppler could be limited by a low
frame rate. Furthermore, 3D color can help identify, assess, and localize residual eccentric or wall-hugging
MR jets not seen on 2D color flow imaging. However, to date there is no sufficient data to routinely
recommend 3D VCA as a strong parameter to quantify residual MR after clip placement;
(3) The pulmonary vein flow pattern is very useful to assess residual MR grading. Normalization of
pulmonary vein flow after MV interventions strongly suggests that MR has been reduced to mild;
(4) Invasive hemodynamic parameters, such as the resolution of regurgitant atrial v wave and reduction of
left atrial or pulmonary pressures, provide important additional clues to improvement in MR severity. It is
also common to observe an increase in systolic blood pressure immediately after a successful reduction in
severe MR, reflecting an increase in forward stroke volume;
(5) The mitral inflow velocity pattern (decrease in mitral E velocity and velocity time integral) may be
helpful in assessing reduction of MR, as a change from an E-wave-dominant to an A-wave dominant
pattern could suggests mild residual MR. A diastolic TMPG rise, without significant reduction of MVA
could be an indirect sign of residual moderate or greater MR. In such a setting, an additional Clip may
“paradoxically” reduce the diastolic TMPG by the improvement of MR;
(6) Appearance of spontaneous echocontrast in the LA after MV repair also suggests significant reduction
in MR severity;
(7) Left ventricular outflow tract velocity integral as assessed in deep transgastric views may be helpful in
demonstrating an increase in forward systemic flow;
TM
(8) A decline in LV ejection fraction after MitraClip procedure also could suggest significant MR
reduction and thus increased afterload.

System removal
After release of the Clip, the CDS is withdrawn into SGC. The distal end of the DS, also called the
atraumatic tip, may injure LA structures during withdrawal into the SGC. This maneuver is usually
monitored by multiple views in 2D imaging. At this stage, an intermediary between short axis and bicaval
views, is also useful to confirm that the SGC is maintained sufficiently into the LA, as a second Clip
implantation may be required. If no additional Clip is needed, the SGC is withdrawn back across the IAS
and out of the femoral vein access.

Atrial septal defect evaluation
After system removal, the residual shunt and size of iatrogenic IAS shunt should be evaluated. Assuming no
additional damage to the septum and predominantly left to right flow, the defect is generally of no clinical
[14]
significance .

Complications
Percutaneous edge to edge MV repair is generally a safe procedure with good hemodynamic tolerance
even in high-risk patients and is associated with few major complications [15,16] . Serious complications may
occur at a low rate and can be promptly identified by echocardiographic monitoring during the procedure.
Potential complications may be represented by:
(1) The occurrence of thrombus on intracardiac devices, such as guidewires and/or delivery sheaths;
(2) Acute severe hypotension caused by cardiac tamponade, acute decline of LV function, or worsening of
MR;
(3) Pericardial effusion and cardiac tamponade due to perforation of the LV free wall or aortic puncture
during TSP;
(4) MR worsening, subtended by three major mechanisms: leaflet or chordal damage; loss of leaflet