Discussion
To the best of our knowledge, this is the first report describing a
group of patients in whom transcatheter prosthetic MV implantation
utilizing the transapical method was accomplished for a severely
degenerated MV prosthesis or severe native MV stenosis status post a
surgically inserted mitral annuloplasty ring with co-existing thrombus
in the LAA and/or LA body. In a prior publication comparing surgical
versus transcatheter MV in prosthetic MV patients, two patients with
thrombus in the LA were listed in a table, but there was no further
mention and no other details were provided in the published
manuscript.12 Since fluoroscopy does not visualize
intracardiac thrombi, use of both 2D and 3DTEE was essential in finding
the location and other attributes of the thrombi such as their size and
extent in our patients and guiding the transcatheter procedure such that
there was no contact with the thrombus at any time. Although in all our
patients, the procedure could be successfully performed avoiding any
disruption of the thrombus, it may be difficult to avoid it if the
thrombus involved the prosthetic valve or was very close to it or was
closely related to other anatomic landmarks normally used during the
procedure such as the left upper pulmonary vein. However, in all our
patients, the thrombus did not involve any of these sites by both 2D and
3DTEE further ensuring a successful outcome without any complications.
3DTEE provided incremental value over 2DTEE in more comprehensively
assessing both the LAA and LA body for the presence and exact sites of
location of thrombus, its size, shape and mobility characteristics as
well as thrombus volume which is a superior parameter of size than
thrombus area measured by planimetry.9,13,14 These
findings helped the operator in carefully guiding the guide wire and the
prosthesis deployment system as they traversed through the degenerated
bioprosthetic MV/native stenotic MV and annuloplasty ring into the left
atrium bypassing the thrombus. In all our patients, 3DTEE, unlike 2DTEE,
also facilitated en face view of the degenerated bioprosthetic MV
leaflets which permitted accurate measurement of the orifice area by
planimetry.15 In addition, color Doppler en face views
of vena contracta of the mitral regurgitant jet facilitated measurement
of vena contracta areas permitting more accurate assessment of
regurgitation severity.16 3DTEE also provided
increased confidence level during deployment of the MV prosthesis.
Another additive value of 3DTEE was the ability to ensure the absence of
any residual valvular or paraprosthetic MR following the procedure with
a greater degree of certainty than using 2DTEE alone since the
prosthesis could be viewed in multiple projections.