Circulation October 25, 2016 Issue

 


Carolyn:
Welcome to Circulation on the Run, your weekly podcast summary
and backstage pass to the journal and its editors. I'm Dr.
Carolyn Lam, associate editor from the National Heart Center and
Duke National University of Singapore. We have such a special
podcast for you today. The entire podcast is going to be a
conversation with two very special guests, Dr. Marc Ruel from The
University of Ottawa Heart Institute, the guest editor of the
surgery themed issue this week. Hi Marc.


 
Marc:
Hello Carolyn. How are you?


 
Carolyn:
Very good. Especially because we also have Dr. Timothy Gardner,
Surgeon, Associate Editor from Christiana Care Health System.
Welcome back again, Tim.


 
Timothy:
Thank you, Carolyn. Glad to be here.


 
Carolyn:
Marc, could you first give us an overview of the surgery themed
issue from your perspective.


 
Marc:
This year as we have had on previous years, we are having a
surgery themed issue which comprises what I would argue which is
some of the very best cardiac surgical science can offer to the
wide readership in the cardiovascular community that served by
circulation. This year, we will have a total of ten articles that
would be published in circulation, as a section of one of our
regular issues and out of those ten, there are five original
papers. There's one research letter which is an original research
article but in a shorter format and we'll also have one invited
perspective paper namely about coronary artery bypass grafting
and its future with respect to multi-arterial grafts and the
themed issue will be completed by three state of the art papers
that deal in a very in depth comprehensive way with some
important problems that the cardiovascular community faces from a
clinical point of view.


 
Carolyn:
Thanks Marc. That was a beautiful summary of the issue. I
couldn't help but notice that there was a theme of coronary
artery bypass surgery covering at least four of the papers and I
really like your thoughts on that. You covered everything from
medical therapy, CABG versus PCI, on versus off-pump, emergency
surgery in the setting of shock. Could you go through each of
these four papers a little and tell us what was your take home
message from each?


 
Marc:
As you said, there are three original research articles and one
invited perspective that relate to coronary artery bypass
grafting surgery and these encompass the number of clinical
problems that are still controversial and certainly I believe
they contribute a very, very significant [inaudible 00:02:31]
with the wealth of knowledge that the cardiovascular community is
looking for at this point. If I may go one by one, just with a
very high level overview, if you will. The first one is a paper
from the Leipzig Heart Center with first author, [Pieroz Adewalla
00:02:45], which looked at surgery for acute myocardial
infarction but accompanied with cardiogenic shock. As you know,
many patients undergo surgery in an acute MI context, but surgery
for cardiogenic shock is often a very gruesome difficult
decision.


 
 
Leipzig Heart Center looked at over 3,000 patients who had an
acute MI prior to cardiac surgery for bypass surgery and of
these, there were 508 patients who actually had cardiogenic shock
due to [valve 00:03:15] failure with myocardial dysfunction and
to give you an idea, these patients were quite sick. There's
about 40% of the patients who were ventilated prior to surgery or
very close to 40%. The timing was quite urgent, those patients
were on inotrophes and on vasopressors to support their blood
pressure prior to operation. Essentially, what they found is that
first the outcomes got better over the last number of years, this
is a series that dates back to about the 2000's, so the early
2000's.


 
 
They also favor an approach where they tried to avoid a
cardioplegic arrest of the heart. Their favored overall approach
is to do what we call on-pump beating heart type of surgery which
would be a surgery where the cardioplegia would not be
administered to stop the heart but the hemodynamics would be
supported for the cardio coronary bypass. They also have over the
years since the beginning of this year, is in 2000 ranging up to
2014 of increasing the use of the off-pump bypass surgery and
certainly the outcomes have been better and the mortality
although high has decreased significantly. It was as high as 40%
in the early parts of the cohort if you will and in the latest
third of the experience, therefore from 2010 to 2014, the
mortality has been down to about 25%.


 
 
Again, these are patients who present with cardiogenic shock.
What's also interesting to note is that patients who survive out
of hospital still have a significant mortality burden and about
50% of them survive long term. What was interesting is the 
Leipzig group is looking at some predictors of bad outcomes in
those patients and they found that the serum lactate over four
minimal per liter was actually a very robust and multi-variative
predictor of a poor outcome after surgery.


 
Carolyn:
That was a great summary of that first paper. You mentioned
beating heart surgery and so on. Would you like to comment on
next paper that I think was the largest single institution
European study comparing on versus off-pump bypass surgery?


 
Marc:
You're absolutely right. This is a paper from England, [inaudible
00:05:25] from Liverpool, where the patients were gathered from
and with some contribution from Oxford as well from a statistical
and methodological point of view and it's a retrospective cohort
study of all isolated CABG patients in Liverpool between 2001 and
2015. These are bypass surgery patients and in total, there were
over 13,000 patients who had CABG. About 6,000 patients had off
CAB which is off-pump bypass surgery and more than 7,000 had
bypass with cardiopulmonary bypass. The median follow up was 6.2
years. What's interesting in this paper is that they essentially
found equivalent long term outcomes. As you know, there has been
some debate regarding the completions of myocardial
revascularization and the long term graft patency with off-pump
surgery versus on-pump surgery. Also named conventional CABG.


 
 
What's interesting here is that the benefits of off-pump CABG
appear to be seen early on with regards to antiemetic release as
stroke rates, etc. Which does correspond to some of what has seen
in the randomized controlled studies. However, the long term data
is interesting. There's a a nice editorial about this paper
written from a group from the Cleveland Clinic with Dr. Joe Sabik
as the senior author and essentially it raised a number of good
points, although this is an important series, it also shows that
the surgeons who are very good at off-pump bypass surgery may
overall be slightly technically more skilled at doing bypass
surgery in itself and for instance, use more often arterial
grafts and have more advanced techniques in their completion of
bypass surgeries for their patients.


 
Carolyn:
Right. I'm so glad you mentioned the editorial. I was about to
bring that up as well. Switching gears to you very kindly
included a paper that talked about medications and the impact of
here is the medical therapy on the comparative outcomes between
CABG and PCI. Would you like to discuss that paper?


 
Marc:
This is a paper from the Care Registry which has generated some
interesting publications in the past. The lead author is Dr. Paul
Polinski and there's co-authors, Dr. Herbert Prince and Michael
Mack from Dallas as well. This was presented at the science
sessions in Orlando last November and it's an interesting paper.
Essentially they have looked at large databases, again the Care
Registry which comprises eight community hospitals and they look
at six month period of performance of CABG and those eight
community hospitals. They ended up with over 2,700 patients who
were then systematically followed on a regular basis up to 2009
at which time the database was locked.


 
 
They look at various outcomes but also medication use in great
detail over that period of time and the interesting perspective
that this paper brings is that first, most patients at least in
that period were not on optimal medical therapy. The authors used
their own predefined definitions of what constitutes optimal
medical therapy and this is with regards to adherence to aspirin
use, lipid lowering agents, beta blockers and indicates of PCI,
dual anti-platelet therapy. As expected but nicely documented in
this paper, the outcomes of patients who were not on optimal
medical therapy were much worse than those who were and CABG
proved to be more robust in patients who were not on optimal
medical therapy compared to PCI.


 
 
The differences between CABG and PCI in patients who were on
optimal medical therapy tended to vanish. However, a number of
caveats here is that only 25% of patients in fact in this cohort
were on optimal medical therapy. The vast majority of patients
were not considered to be on optimal medical therapy. Therefore,
there are considerations of definitions that one has to be aware
of and also considerations of statistical power because the group
that was on optimal medical therapy was much smaller than the
other group. Therefore, the effects, the superiority of CABG over
PCI could only be firmly demonstrated in the group was not on
optimal therapy, again comprising 75% of patients in this cohort.


 
Carolyn:
I love your summaries and they really show that these are true
significant original contributions to that knowledge gaps in
coronary artery bypass surgery. To round it all up, you also
invited a perspective on novel concepts. Would you like to
comment on that paper?


 
Marc:
This is an invited perspective in the view classifications that
circulation has which is entitled, "The evolution of coronary
bypass surgery will determine relevance as a standard of care for
the treatment of multi-vessel CABG." It is authored by three
leaders in the field, Dr. Gener, Dr. Gudino, and Dr. Grouw. Dr.
Gener has been leading several of what I would call the advanced
multi-vessel coronary re-vascularization trials looking for
instance at multi-arterial grafts doing numerous anastomosis with
two ventral mammary arteries in a wide fashion. He's been a
leader of this movement certainly. Dr. Gudino recently published
[inaudible 00:10:43] the 20 years of outcome of the radial artery
graft and certainly has been one of the pioneers which use of
this arterial graft for coronary artery bypass surgery. What the
authors provide here is a very nice summary of what the trials
have shown so far and they also report as many know that their
rate of multi-arterial grafts use in SYNTAX, FREEDOM and I think
we will soon see in EXCEL and NOBLE that will be presented this
fall, has not been as high as it should have been.


 
 
In the US, it is estimated right now that the rate of use of more
than one mammary artery is less than 10% across the nation, and
other countries have not performed better than this either. This
perspective is a call to improving the quality of multi-vessel
coronary artery bypass mainly through the use of multiple
arterial re-vascularization. There is also considerations around
the hybrid coronary re-vascularization and as well as the use of
off-pump versus on-pump surgery.


 
Carolyn:
I am really proud and privileged to have helped to manage one of
the papers as associate editors in this issue as well and that is
the paper from the group with corresponding author, Dr. Veselik,
from Boston Children's Hospital and it centers around patients
with congenitally corrected transposition of the great arteries
but a management problem that is really increasingly encountered
and really needs to be reviewed properly and that is the
management of systemic right ventricular failure in these
patients. Tim, you were so helpful in looking at this paper as
well. Could you share some of your thoughts?


 
Timothy:
Well, this is a somewhat unique situation where a patient with
this condition, congenitally corrected transposition of the great
arteries may go through early life, in fact may end up as a young
adult before this particular condition is identified because if
there is no shunting or no cause for cyanosis and heart murmurs
and so on early on, the circulations seem to work pretty well
until the poorly prepared right ventricle which is the systemic
ventricle, starts to fail after years of work carrying the
systemic circulation and that is really the focus of the paper.
There's been a lot of work and publications and attention to
transposition syndromes but this particular one is a condition
that may be first encountered by adult heart failure cardiologist
who have not had this kind of exposure to congenital heart
disease. It's a particularly apt paper to bring this condition to
our attention and to demonstrate that really it's the adult heart
failure cardiologist who may be managing these patients in their
late 20's or 30's, when that systemic right ventricle fails
because of a lack of formation to manage the systemic
circulation.


 
Carolyn:
Exactly. Written by a group that has one of the most robust
experiences in this field, so that also brings to mind another
state of the art article in the issue that refers to the
hypoplastic left heart syndrome and though it's entitled that and
people may think it's rare, I think it's increasingly being seen
in the adult cardiology world as well. You want to comment on
that one?


 
Timothy:
That actually is one of the main points of this paper that this
very, very difficult condition of hypoplastic left heart syndrome
that requires staged operations beginning in the neonatal period
has now reached the state of surgical accomplishment in medical
management where many of these young children are surviving into
young adulthood. Albeit, with having had two, or three, or four
operations. In a community like ours here in Delaware, where
pediatric patients transition to adult services and adult
cardiologist sometime around their 20's, it's really important
for the entire cardiology community to be aware of what has
happened in terms of the successful staged treatment of children
with hypoplastic left heart syndrome and that is brought out very
nicely by the three authors who look at various accomplishments
and different techniques for managing these staged repairs. It is
very amazing to someone who has been observing this field for
sometime as I have, that many of these children are in fact
surviving into young adulthood and will require comprehensive
cardiovascular treatment, not just by neonatal specialist but by
specialist in adult congenital heart disease.


 
Carolyn:
Exactly, which is why such a timely state of the art articles
both of them for this issue. There is another state of the art
article that you were handling, Tim, "The Surgical Management of
Infective Endocarditis Complicated by Embolic Stroke", now that's
an important topic.


 
Timothy:
Absolutely, as we know up to a half or more of patients with
infective endocarditis primarily on their left sided heart valves
will have cerebral embolic problems and it has really been a
dilemma for many of us in terms of optimal timing for the cardiac
surgery with respect to the existence of cerebral injury from the
embolism, from hemorrhage that may occur, from hemorrhage that
may be exacerbated by placing the patient on the heart-lung
machine, etc, and this paper really takes an extremely
comprehensive, careful and judicious look at all of the evidence
that has emerged and it has been a confusing field of evidence as
to how to best optimally manage these patients with cerebral
involvement from infective endocarditis.


 
 
I think this paper is going to have a big impact. It appears that
there are a couple of messages that I took away from this paper.
Number one, we really need to use the full panoply of diagnostic
opportunities or diagnostic test for characterizing the nature
and the extent of the cerebral involvement in these patients and
then perhaps even more important, we need to convene what the
authors called the infective endocarditis team and that has to
include not just the surgeon, the cardiologist and the infectious
disease specialist but also the neurologist, the
neuro-interventional specialist, the neurosurgeon and so on
because all of these specialist need to contribute to the
assessment and choosing the optimal timing for these patients.


 
 
That is the central message of the paper. The authors also
suggest that we may be getting to the point where we need to
update and make sure that the guidelines that we're using are in
fact current. Current in the sense that the experience now with
advance imaging and with more aggressive management of the
neurological or cerebral issues really need to be factored into
how best to handle these patients, but I think this paper is
going to have a big impact, it's very well written and very
thorough.


 
Carolyn:
I agree. In fact all the content we just discussed is just so
rich. Congratulations on such a beautiful issue. Marc, do you
have any last highlights you'd like our audience to hear about?


 
Marc:
I'd like to also mention two other original research papers that
will be featured in the surgery themed issue. One, in keeping
with the congenital theme that we had talked about is about the
modified [Straun's 00:19:08] procedure for palliation of severe
Ebstein's anomaly and this is a series actually from Professor
[Straun 00:19:16] himself mostly originating from Children's
Hospital Los Angeles and essentially, the series here is that of
27 patients about equal in gender distribution who were operated
at seven days of life, between 1989 and 2015.


 
 
It's very interesting that patients did well, the survival at ten
years is 76% and most of them have undergone successful Fontan
completion. I think this is a very important paper not only
because it is an extremely vexing and difficult problem to deal
with Esbtein's anomaly but it comes from the innovator of the
operation himself with his team and it provides much needed data
regarding the long term outcomes of these children with this very
difficult solution. I think this will be of great interest and
also as we commented before veering into the world of adult
cardiology as well, because fortunately most of these patients
survive into adulthood.


 
 
The other paper I wanted to touch upon which is also an original
research paper that will be in this themed issue, is a paper from
the CTSN Group looking at the impact of left ventricular to
mitral valve are being mismatched on recurrent ischemic MR after
ring annuloplasty and this paper used the free innovative and
interesting methods. As some of you may know, there were two
large files recently that were conducted by the CTSN looking at
either moderate MR at the time of coronary artery bypass grafting
or at severe ischemic mitral regurgitation. The randomizations
were different when the moderate MR was CABG lone versus CABG
post mitral valve repair and the severe MR was mitral valve
repair versus mitral valve replacement.


 
 
These studies have led to interesting conclusions that several
will know about but what's been interesting in the current study
is that they have gathered all patients who underwent mitral
valve repair from both studies, original randomized trials and
they ended up with about 214 patients who underwent mitral valve
repair. The others had moderate or severe MR and basically the
point of this study is to look at predictors of failure of mitral
valve repair and this is an extremely relevant problem, not only
for the cardiac surgical community I would venture, but also for
heart failure community and for JV General cardiology community.
What the others found is that the most important predictor of
recurrent mitral regurgitation after mitral valve repair was
something called the left ventricular and systolic diameter to
ring size ratio and they provide an algorithm which will have to
be tested clinically with regards to whether it is applicable and
indeed changes outcome, but this is a very important discovery in
the field of ischemic MR and enabling us to hopefully better
understand and improve outcomes for patients with this very
difficult problem.


 
Carolyn:
I agree. Thank you so much, Marc and Tim for this most insightful
discussion. Thank you very much and to the listeners out there,
don't forget you've been listening to Circulation on the Run.
Join us next next week for more highlights and features.