Carlos A. Mestres, MD, PhD, FETCS
Clinic for Cardiac Surgery
University Hospital Zürich,
Rämistrasse 100
CH 8091 Zürich (Switzerland)
Email:
Carlos.Mestres@usz.ch
In this issue of the Journal of Cardiac Surgery, Huckaby et al (1) aimed
at evaluating the impact of secondary functional tricuspid regurgitation
(STR) and concomitant tricuspid valve repair (TVr) when operating
left-sided valves. All patients undergoing left-sided valve surgery
between 2010 and 2019 were retrospectively reviewed and grouped
concerning the degree of TR and associated TVr. The authors collected
3,444 patients over a decade distributed in less-than-moderate TR
without TVr (G1), more-than-moderate TR without TVr (G2) and
more-than-moderate TR with TVr (G3) groups. The authors concluded that
those patients with more-than-moderate TR without TVr when operating a
left-sided valve had higher mortality and hospital readmissions. Our
colleagues strongly recommend doing something on the tricuspid valve
when we operate on the aortic or the mitral valves. Strong message, do
not leave the tricuspid valve unattended!
It is clear that this interesting contribution has limitations. Some are
acknowledged by the authors. Important is that their rate of
completeness of follow-up is rather poor. First, they lost control of
10% of the cohort at 1 year postoperatively, with only 49.6% of the
patients with some follow-up information at 5 years. By definition, this
actually invalidates part of the analyses as the statistical power may
eventually fall into a black hole. It is clear for quite long time that
surgeons must have full control of the evolution of their patients over
time; this has been addressed before (2). We probably have to accept
this suboptimal follow-up and focus on this contribution including what
we could call large study population, close to 3,500 patients. Is there
some balance between the good and the bad parts?
It seems that insufficiency was the only criterion for TVr as per
methods, unclear if authors took into account annular measurement or
indexed values. Important and unknown is that if TVr was performed with
the clamp on or the heart beating to justify some longer ischemic times
Furthermore, if during the follow-up the authors considered the effect
of annulus measurements on late degrees of tricuspid regurgitation. It
is likely that due to the retrospective design and the very low
completeness of follow-up, these important questions cannot be fully
addressed.
The tricuspid valve is still an obscure, even somewhat tantric complex.
Is this because our knowledge is still limited? Is this because we are
reluctant to add extra time under non-physiological conditions of
cardiopulmonary bypass in patients with, e.g., mitral disease with
pulmonary artery hypertension? Guess we still have no strong answers to
many other questions. There is growing information that TVr plays a role
in preventing mortality and improving outcomes in left-sided valvular
surgery (3, 4), something which is supported in this current Huckaby et
al contribution (1). This is most likely due to the control of
regurgitation with positive impact on right ventricular function and
pulmonary pressure. Although the gut feeling predominated decades ago
and most of us decided to disorderly perform TVr of any kind, data were
no solid to support action on a regular basis, especially due to the
lack of robust follow-up data over time, beyond five years. Recent
information from meta-analyses (5) and institutional series (4) tend to
recommend TVr. The discussion about patients who might need tricuspid
replacement should also be kept in mind, as it is likely that patients
requiring repair or replacement are different populations.
As we have already pointed out earlier, it may happen that our
understanding of the disease and its different forms is still suboptimal
(6), considering that, as stated, accumulated information is based on
retrospective studies covering long periods of time or observational
studies with large differences in sample sizes and variability in
inclusion criteria. Second, we have restricted room to expand our
knowledge, because methodologically sound studies are not easy to design
and execute when one considers logistics and finance among other issues
(6).
Another topic of interest derived from this contribution (1) is the old
problem of what to do in the tricuspid valve. Huckaby et al confirmed
that they only performed partial annuloplasty ring repairs (1). Not
confirmed if rigid, flexible or semi-rigid. As said, the suboptimal
follow-up precludes deeper analyses on the influence of a given
technique or a given ring. Classical implantations of flexible or rigid
rings have been assessed by a number of authors with controversial
outcomes. Algarni et al (7) confirm similar outcomes regardless of the
ring but with more late TR when rigid rings are implanted. There is more
controversy, as data from Shinn et al (8) showed no influence of the
method of annuloplasty used on recurrence of TR over time in a 15-year
experience, therefore challenging studies. Lack of standardization is
still an issue and many answers will need studies known to be difficult
to perform (6).
Finally, the problem of permanent pacemaker implantation (PPM) cannot be
neglected when concomitant TVr is performed, especially in the setting
of mitral valve surgery. This has been infrequently addressed in the
past (8, 9). Jouan et al (10) confirmed an increased risk of
postoperative PPM in the cases of concomitant TVr at the time of mitral
surgery. The eventual role of shape and rigidity when using a prosthetic
ring for TVr has still to be elucidated. It is known that TVR
annuloplasty is a risk factor for postoperative conduction
abnormalities. Huckaby et al. described postoperative arrhythmias in
relation to less-than-moderate TR without TVr (G1), more-than-moderate
TR without TVr (G2) and more-than-moderate TR with TVr (G3) of 11.29%,
20.43% and 24.91%. Unfortunately, we are not informed if these
arrhythmias were transient or permanent or when was PPM indicated. In
any case, as also stated earlier, the fine balance between performing a
procedure to benefit patients and withholding an additional maneuver to
avoid harm in the absence of compelling indication is one that appears
particularly relevant to this discussion (11).
In the end, STR has been identified as a growing problem in recent years
due to missconceptions (12). To summarize, Huckaby et al (1) have
brought again the attention of the readership to a still active and
unsolved problem. They highlight the impact of TR on outcomes among
patients undergoing left-sided valve operations, aortic and mitral as
they pooled all together, which might be a matter of discussion.
Moderate-or-greater TR led to more deaths and readmissions and the
important part of their conclusion remarks is that patients who
underwent concomitant TVr did not die more than patients with lesser
degrees of TR. Therefore and in line with other studies suggesting the
more and more frequently we must address TR at the time of left-sided
valve surgery (13).