CONCLUSIONS
A partner cohort study [8] showed that PVL (more than mild) was
associated with an increase in the incidence of late mortality and
severe PVL in the Pivotal Extreme Risk Trial. 9 A
meta-analysis by Athappan et al.10 showed that in
patients with moderate and severe PVL, the 1-year survival rate was
reduced.
The presence of mild or more significant PVL after TAVR increases the
incidence of mortality in the long-term.11,12 In the
REPRISE III trial, the incidence of stroke events was increased in
patients with mild PVL after TAVR. This indicated an association between
PVL and stroke events. This raises the question of whether PVL may
increase the risks of other postoperative
complications.13 No practical method or uniformly used
strategy for predicting PVL has been reported yet. It has been shown
that one of the most significant predictors of paravalvular aortic
regurgitation are valvular and annular calcium, which can predict PVL
with a sensitivity and specificity of 86% and 80%, respectively, if
the valvular calcium score was above 3,000.14 By
applying such information, the sensitivity and specificity of the
presence of cyclic calcium (i.e., asymmetric calcium) is a moderate
predictor of Grade I or higher PVL.15 Reiff et al.
reported that reproducing a high-fidelity model of the human aortic root
was feasible in a clinical setting and did not require composite models
and expensive printers. Furthermore, implanting a TAVR valve within a 3D
printed model could aid predicting PVL. In the absence of adequate
therapy for PVL, it is essential to develop a high-fidelity
computational model to predict PVL.15 Revolutionary
valve-implantation technology and improved preoperative planning with
electrocardiography-gated multislice 3D-CT have overcome some complex
problems16; however, PVL remains a problem in
TAVR.17There is minimal PVL in conventional SAVR
because the principle of SAVR is to remove as much calcification as
possible in and around the annulus during SAVR. Many reports suggest
that PVL does not affect mortality, cardiac accidents, deterioration of
prosthetic valves, or artificial valve infection in the
long-term.18,19 However, in addition to the above
information, a meta-analysis of TAVR raised concerns that even mild
perivalvular regurgitation can be detrimental to patient
survival.20,21
RD-AVR has a low rate of PVL (severe aortic regurgitation(AR) 0.2%,
moderate AR 1.2%, mild AR 6.1%), but these values are still higher
than those reported after conventional SAVR
interventions.22
The rate of significant postoperative PVL was 3.7% in the bicuspid
aortic valve. These data are similar to those reported in previous
studies. However, the risk of postoperative AR is 2.5 times higher than
that of the total population of the SURD registry. We believe that it is
essential to understand the complexity of the anatomy of bicuspid aortic
valve (BAV) and restore the annular circumference for complete
results.6, 22
To reduce PVL incidence, Andreas et al.23 reported the
application ofan extra stitch in the noncoronary sinus in selected
patients, and they did not implant this particular type of valve in
patients with extensive calcifications of the root with rigid sinuses.
Furthermore, SURD-IR data collection for more than 12 years showed that
the incidence (17.8% to 2.7%)(Figure 1)and severity (severe AR 0.6%
to 0, moderate AR 3.1% to 1.1%, and mild AR. 14.1% to 1.6%) of
postoperative PVL decreased significantly. This may be due to the
increased surgical experience in RD-AVR surgery.24
By observing preoperative data, Chirichilli et al. found that bicuspid
aortic valves have a larger mean annular size in terms of area and
perimeter compared to tricuspid aortic valves. This preprocedural
anatomical finding might explain why preoperative CT scans showed an
elliptic shape of TAVs (Ellipticity Index 1.3 ± 0.1), a circular shape
of type 0 BAVs (1.1 ± 0.1) and an intermediate behavior of type 1 BAVs;
this suggested a possible gradual spectrum of TAV circularity from type
1 BAV to type 0 BAV circularities.25 In our study, the
3D-CT reading was larger than the UCG reading, and the actual
replacement prosthesis size was closer to 3D-CT tasks. Preoperative
ellipse was not associated with perivalvular regurgitation, but
perivalvular regurgitation was more common in patients with a large
aortic annulus. This may be related to the large aortic annulus and the
possible loss of active elasticity in the bicuspid valve.
We encountered four cases of PVL in the first half of this series, and
one patient had hemolytic anemia, which required the replacement of the
aortic valve. In our experience, regurgitation from the RCC-NCC
commissure was the most common form, followed by regurgitation from the
LCC-RCC commissure. It has been found that choosing a smaller prosthesis
to avoid implantation of a new pacemaker or left bundle branch block
increases the likelihood of having a gap in the commissure. If the
height of the prostheticvalve is adjusted to the nadir, it will be in
the infra-annular position at the commissure. Therefore, it was also
found that a form with the commissure being high and spreading outwards
had much regurgitation around the prosthetic valve. This morphology is
especially common in bicuspid aortic valves. Ferrari et al. reported
that the aortic annulus stabilization technique based on an already
performed annuloplasty of the aortic annulus that uses a running 3–0
polypropylene suture was sufficient to prevent PVL.7However, our findings suggest that the elliptical shape of the annulus
is not associated with PVL, and this is owing to a gap under the RCC-NCC
commissure. Therefore, the additional stitch that we performed was easy
and quick.
We changed the technique in the last 18 cases and inserted an everted
mattress stitch at the commissure; the artificial valve was pulled up to
the commissure and fixed. This extra stitch eliminated PVL
complications, and there were no PVL incidences in the later 18 cases.
We often choose a smaller-sized valve RD-AVR to avoid complete
atrioventricular and left bundle branch blocks. In such cases, we are
concerned about PVL, but we think this new stitch is a very effective
way of eliminating PVL.
This study has some limitations. This was a retrospective case series
with a small number of patients, meaning that there is also a risk of
bias; there was also a potential for selection bias given that
participants were all from a single university hospital. This did not
allow us generalize the results of this study to different populations.
Additionally, we reported only RD-AVR cases and did not show comparative
data with conventional SAVR and TAVR. In future studies, we need to
confirm the anatomical analysis of PVL for all aortic valve stenosis
patients and long-term results and compare patients with and without
PVL.
PVL is a rare complication of RD-AVR that may require reoperation and
should be avoided. 3D-CT can measure PVL more accurately than UCG and is
a useful test method for predicting PVL. We conclude that PVL is more
likely to occur if there is a gap below the R-N commissure, especially
in cases with large annulus sizes. In such cases, applying an additional
stitch to the R-N commissure is extremely useful.
Acknowledgments: We would like to thank Editage
(www.editage.com) for English language editing.