Download Surgical left ventricular reshaping in postinfarctual cardiomyopathy

CLAUDIO GROSSI
Cardiac Surgery
Ospedale Santa Croce
CUNEO (Italy)
Surgical left ventricular reshaping
in postinfarctual cardiomyopathy:
an unresolved issue
There are different possible ways to discuss this
important topic:
ü  Following the historical evolution of
scientific events
ü  Showing the rich literature of clinical
I choosed the
effects
last one: ….I want to discuss with you
ü  Looking at the physiopathological aspects
Consequently
ü  Talking
I’m not
about
goingthe
to consequences
give you any solution
of
STICH trial
ü  Speculating about the future possibilities
of applying new approaches
ü  Discussing the discrepancy among all
those aspects
Post-infarctual ventricular remodeling
“It is now widely appreciated that
remodeling is not just a
manifestation of disease,
but is an important mechanism of disease”
The surgical treatment of LV aneurysm was
introduced in 1944:
•  Claude S. Beck reinforced the wall of a left ventricular (LV) aneurysm
with fascia lata aponeurosis in order to reduce excessive dilatation and
avoid LV rupture
•  Further developments of LV aneurysm surgery lead to the use of
numerous new LV reconstruction methods.
•  The principal surgical techniques can be divided into two large
groups:
Ø  the direct suture techniques
Ø  the patch ventriculoplasty techniques.
•  The direct suture
techniques
•  The patch
ventriculoplasty
techniques
SVR: Surgical Ventricular Reconstruction
to
d
e
gn erior
i
s
e
s d he ant
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re
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R d ct pos ft ventr
V
S
• 
ra
le
e
t
e
z
n
i
u
tim
co
p
o
to
l
l
a
w
“SVR: ..new term which includes operative methods that
reduce LV volume and “restore” ventricular elliptical shape.”
RESTORE group: The Reconstructive Endoventricular Surgery, returning Torsion
Original Radius Elliptical Shape to the LV
• 
The RESTORE group applied SVR to 1,198 post-infarction patients between
1998 and 2003.
Ø  Surgical ventricular restoration reduces volume and “restores”
a more normal elliptical ventricular shape in dilated hearts after
anterior infarction.
Ø  Our data demonstrate a low operative mortality, improved systolic
function, a gratifying five-year survival, and a low rate of
rehospitalization for CHF..
Conclusions
•  LVR surgery was accompanied by a favorable neurohormonal response. Decreased
profiles of selected neurohormones were associated with improved LV function.
•  These results support the hypothesis that direct improvement of cardiovascular function
may reduce neuroendocrine activation by removing trigger mechanisms.
Cuneo, 2000-2009: 138 Pts
Operative mortality 6/138: 4,4%
100
Survival
80
60
40
20
0
0
6
12
18
24
30
months
Short term follow-up:
avarage 14,5 months
(update to 2006)
36
42
•  …The SVR literature largely consists of
retrospective single-center or multicenter
database reviews
•  To address this question, the STICH trial was
designed to study the additive effect of SVR on
revascularization in a prospective randomized
fashion.
Death or Cardiac Hospitalization
Kaplan-Meier Estimates of Primary Endpoint
0.7
HR 0.99 (95% CI: 0.84, 1.17), P=0.90
Event Rate
0.6
0.5
0.4
0.3
0.2
CABG
292 events
0.1
CABG+SVR
289 events
0
0
1
No. at Risk
CABG
499
CABG+SVR 501
319
319
2
3
4
Years from Randomization
270
275
220
216
99
11
5
23
23
Conclusions
Ø  The STICH trial definitively shows adding SVR to CABG
provides no clinical benefit beyond that of CABG alone
in the study population.
Ø  Both operative strategies provided similar short- and
long-term relief of angina and HF and improvement in
6-minute walk test performance.
•  From 2002 to May 2008, 274 patients underwent left ventricular
reconstruction for post–myocardial infarction scarring;
•  117 of these patients would not have been eligible for the
STICH trial.
•  Results:
ft year.
e
l
,
y
ü Four in-hospital and 2 delayed deaths during
the
first
t
ali
t
r
o
m
d
a
e
t
h
t
e
a
i
l
i
b
c
w
a
•  In 101 patients with chronic heartafailure,
revealed
that
r
so MRI
u
s
nts
d
e
i
l
s
t
a
e
a
p
im
uc
n
n
d
i
i
o
n
r
m
o preoperatively to
p 26%nc±ti4%
h
t
ü ejection fraction
improved
from
n
i
o
i
W
t
u
c
f
s:
u
r
n
r
a
t
o
l
i
s
u
s
n
40%
clu± 8%r ratec1omonthveand
tric44% ± 11% at 1 year postop.
n
n
o
C
t
la
• 
f
ll
u
e
a
l
c
i
w
r
n
t
i
r
n
nt volume
ulaindex was reduced from 130 ± 43
ve end-diastolic
e
ü the
c
i
m
r
t
e
v
n
e
o
r
v
p
d
im
mL/m2
toca81
rre± 27 and 82 ± 25 mL/m2, respectively
s
large
ü the end-systolic volume index was reduced from 96 ± 45 mL/
m2 to 50 ± 21 and 47 ± 20 mL/m2, respectively.
Discussion
• 
Dr Robert H. Jones (Durham, NC):
Has this neutral STICH result changed your equipoise for any of
your health care diagnostic or treatment decisions for ‘‘STICH
like’’ patients, irrespective of whether they were technically
STICH protocol eligible?
• 
•  Dr Robert H. Jones (Durham, NC):
• Dr Dor:
Dr Dor:
(..doesn’t
(..doesn’t
answer) answer)
Has this neutral STICH result changed your equipoise for any of your health
I cannot
understand
why the scarwhy
was not
Icare
cannot
understand
theassessed.
scar was not
assessed.
diagnostic
or treatment
decisions
for ‘‘STICH
like’’ patients, irrespective of
In your trial there is not one indication about the size of the scar, its location, or its
whether
they
were
technically
STICH
protocol
eligible?
In
yourand
trial
there
notit one
indication
aboutthethe
sizewas
of the scar, its location, or its
percentage,
in the
other is
paper,
was never
precise whether
ventricle
scarred.
percentage, and in the other paper, it was never precise whether the ventricle was
Nobody
discussed the situation of when a patient has no more ischemia, a totally
scarred.
destroyed ventricle, and a large scar involving more than 50% of the ventricle: How
canNobody
CABG alonediscussed
improve this patient?
..
the situation
of when a patient has no
more ischemia, a totally
•  Drdestroyed
Dor:
ventricle, and a large scar involving more than 50% of the ventricle: How
CABGyou
alone
improvethe
thisfact
patient?
.. can
Dr Jones
confirmed
that you excluded severe patients to do not pollute your
trial,
.. and our presentation confirms the fact that the STICH trial is not reliable because
patients with a scarred ventricle are not assessed or treated.
Discussion
• 
•  Dr Jones.:
Dr Jones.:
The STICH trial was not designed to definitively answer the question of whether
ventricular reconstruction should ever be done in patients with extensive scarring of
the left ventricle.
designed
to definitively answer the question of whether
The STICH trial was not
We documented
best available
baselinewith
core laboratory
measurement
global
ventricular reconstruction should
ever bethedone
in patients
extensive
scarringofof
and regional dysfunction and ventricular size reported from the ECHO, SPECT, and
the left ventricle.
CMR core laboratories without knowledge of the treatment assignment of the
patient.
We documented the best available baseline core laboratory measurement of global
and regional dysfunction and ventricular size reported from the ECHO, SPECT, and
•  Dr
Dor.core laboratories without knowledge of the treatment assignment of the
CMR
patient.conclusion must add as a conclusion that all the cases that were not treated
…Your
by the STICH study team will be interesting for cardiologists.
Second, regarding the volumes you mentioned, they are assessed by means of
echocardiographic analysis, and again, in 2000’s magnetic resonance is more
reliable to assess the volume of the heart before and after repair.
The credibility of the STICH trial is questioned by
flaws listed below
1.  all patients needed to have akinesia, yet only 50% displayed this
finding.
2.  akinesia developed from regional necrosis of 35% of muscle, yet
the report fails to document this scar finding.
3.  CMR quantification of ventricular volume is needed in all patients
before and after SVR. Instead, 19% underwent an invalid
echocardiographic measurement, despite pretrial contact
showing CMR measurement capacity in all initial 50 trial centers.
(… follows)
4. 100% required CMR volume measurement for trial entry,fuyet
l only
g
n and CABG
i
n
a
38% had any form of volume measurementm(CABG
e
e
y
v
l
e
p
i
plus SVR)
h
s im
a
ac
s
o
m
t
n
o
o
a
r
i
t
f
s
a
e
d is beyond
lu60 mL/m2,
5. SVR is indicated only ifzESVI
ryet volume
c
u
e
t
n
a
o
y
l
n candidates were not
c
a
l
y
n
f
a
i
a
e
measurements
for
SVR
or
CABG
without
SVR
e
tr
d
r
t
n
H
a
u
C
I
c
o
T
h
s
t
S
i
n
reported.
a
e
W
i
h
c
t
i
t
s
s
t
i
l
t
u
a
t
s
s
e
6. 30% reduction
ofaESVI
at 4e.months by CMR study is required for
r
t
h
t
s but ESVI was lowered only 19% in
w
a
o
b
a
h
acceptable
SVR
procedure,
t
s
a
d
d
e
the 33%flof
to demonstrate an inadequate end point.
awpatients
7. the original trial included 50 centers, averaging approximately 10
cases per center. Actually, 96 centers were used, averaging
approximately 5 procedures per center
CASUALTIES OF STICH OUTCOMES
1.  The first casualty of this report may be the increasing CHF
population with dilated hearts, which makes up approximately
half of the CHF population,
2.  STICH may adversely affect cardiac surgery evolution and
nontransplant heart failure surgery by limiting development of SVR
3.  The third casualty is scientific integrity
4.  The fourth casualty may be health care cost of CHF treatment,
which may exceed $1 trillion per year in 2030 in USA
…. Anyway let’s go back to pathophiysiology:
Laplace - Young Law
Radius x Intracavitary Pressure
Wall Stress
=
2 x wall thickness
•  any reduction in diameter of ventricular chamber
corrisponds to a reduction in wall stress
necessary to squeeze the ventricle
What we look for….
A: CORRECT Hypothetical therapy that
would induce a greater
leftward shift of the
ESPVR than EDPVR and
cause an increase in net
pumping capacity as
shown by the pressurevolume loop (blue)
B: WRONG Batista operation
Conclusions:
•  The effect of volume reduction
surgery on overall ventricular
pumping characteristics is
determined by the differential
effects on end-systolic and
enddiastolic properties, which
in turn are determined by the
material properties of the
region being removed.
…few years ago we had,
a clinical demonstration
on humans:
Conclusions:
•  Surgical ventricular restoration achieves normalization of left
Average steady-state pressure-volume loops before (PRE) and after (POST)
ventricular
volumes
and improves systolic function and
SVR,
isolated RMA,
and CABG.
mechanical efficiency by reducing left ventricular wall stress
and mechanical dyssynchrony
…. But
reanalysing
the same data
of the same
patients
other authors
came to a
different
conclusion:
•  The isovolumic pressure–volume
area (PVAISO) is a measure of the
total possible mechanical energy
the ventricle can generate at the
specified preload pressure
•  Thus provides an afterloadindependent measure of the
pumping capability of the heart
•  the relationship between end-diastolic pressure and PVAISO is shifted
downward after SVR, indicating that at any given filling pressure the
heart is capable of less work than before the procedure.
•  In fact, the decreased afterload
and marked elevation of enddiastolic pressure (increased
preload) with no increase in
SV observed after SVR
could actually imply
reduced pumping capability
about diastolic
function…:
•  The changes in the pressure–volume loops and pressure–
volume relationships resemble those observed in classic
cases of diastolic heart failure.
…this was challenged
by professor Dor:
•  … in our recent series the diastolic function
improved concomitantly with systolic function, as
shown by the
decrease in Left Atrial Volume Index,
which is the best witness to the decrease in
diastolic burden.
•  Conventional Doppler echocardiography can assess LV diastolic function by
using transmitral flow velocity profiles (J Am Coll Cardiol. 1997;30:8-18).
Grade of diastolic dysfunction named diastolic pattern as
evaluated by transmitral flow velocity curves
•  67 pts with LV systolic dysfunction
underwent SVR
(LV ejection fraction, 0.27 ± 0.10).
•  Patients
were divided into three
Conclusions:
groups
according
to the
Preoperative
severe
diastolic
preoperative
diastolic
dysfunction may
havefilling
a
patterns
of transmitral
significant
impact onflow
(impaired
outcomesrelaxation,
after SVRpseudowith
normal,
and restrictive filling
heart failure.
patterns).
…on the other hand:
(J Thorac Cardiovasc Surg 2010;140:285-91)
•  Baseline diastolic dysfunction occurs in most patients
affected by ischemic dilated cardiomyopathy referred for SVR.
•  In the present study, we
found that the worsening
in diastolic function
induced by SVR did not
affect clinical status and
survival
(J Thorac Cardiovasc Surg 2010;140:285-91)
•  Patients in whom diastolic restriction develops late
postoperatively had preoperatively larger, more spherical
ventricles with a lower ejection fraction and more conical apex. LV
shape was of nonaneurysmal type
•  A possible explanation is that the significant improvement in
systolic function and the optimal medical treatment, which is
not discontinued after surgery, counteracts diastolic dysfunction
SYSTOLIC FUNCTION
AFTER
SURGICAL
VENTRICULAR
RESHAPING :
.. the improvement in the ejection fraction after the
operation is more algebrical than physiological:
EF= SV/EDV
EF= EDV-ESV/EDV
EDV= a preop.
ESV= b preop.
EDV= a-x postop. if x is the volume removed with SVR
ESV= b-x postop.
EF preop.= (a)-(b) / (a)
EF postop.= (a-x)-(b-x) / (a-x)
EF preop.= a-b / a
EF postop.= a-b+2x / a-x
if x is positive a-b+2x > a-b
if x is positive a-x < a
EF postop > EF preop.
Ø …it is intuitively obvious that reduction of EDV without an
increase in EF would result in inadequate SV.
•  With “usual” inotropic interventions
(adrenergic agents, resolution of ischemia),
an increase of EF results from an increase in SV
with little change in EDV.
•  In contrast, the increase in EF observed with SVR results
from a decrease in EDV with little change in SV
stroke volume:
how does it change with surgical reshaping?
•  Surgical ventricular restoration improves
contractility of myocardium in border-zone and
remote regions, resulting in increased stroke
volume index from the posterior left ventricle.
•  An endoventricular patch on the anterior LV would
seem to exert a restrictive effect on the previously
dilated border-zone myocardium, improving the
contractility of myocardium in the border zone
and also in remote regions.
…BUT:
(J Thorac Cardiovasc Surg 2010;140:1325-31)
•  …several investigators noted a reduction in SV and others
reported an increase in SV
•  …However in our study the response was heterogeneous in
that SVI decreased in 165 (71%) of the patients and increased in
69 (29%) of the patients after SVR.
q This could fit with the theory showing that with regard to the impact on pump
function, SVR could be
ü  detrimental in patients whose wall to be excluded is hypokinesia,
ü  would be neutral in patients whose wall to be excluded is akinetic,
ü  and would be beneficial in patients whose wall to be excluded is
dyskinetic.
(J Thorac Cardiovasc Surg 2010;140:1325-31)
Our data indicate that
‘‘early’’ stroke volume
reduction is transitory
and is linked, at least
partially, to preoperative
ventricular properties
(patients with a SVI
decrease had
a preoperative larger EDV)
Postoperative changes in EDVI, ESVI, SVI, and EF in the overall
study population (248 pts). All changes are significant at P<.001.
(J Thorac Cardiovasc Surg 2010;140:1325-31)
ü  We identified some baseline characteristics of the excluded region
ut SV,
(ie, the degree of dyskinesia) that correlated with theiimpact
on
p
t
u
o
c
a
ard
c
d
n
a
e
c
although the correlation was not
strong.
ran
e
l
o
t
e
s
i
c
xer
e
f
o
t
n
e
•  assessm ercise
x
ü  We hypothesize
characterization
of the excluded
e
f
i
at peak ethat more detailed
l
f
o
ycould
t
i
l
a
u
q
f
o
and non-excluded
regions,
as
be available from modern
t
n
e
m
s
s
e
ss
a
 
•
R.
V
S
magnetic resonance imaging, will lead to improved
understanding
of
f
o
s
e
i
d
u
t
s
e
r
futu
f
o
s
t
c
this matter.
e
p
t as
n
a
t
r
o
p
m
i
would be
•  The dissociation between reductions in SV and overall survival
is reassuring but does not preclude an impact on other important
aspects of overall patient well-being.
•  79 patients with LVEF ≤ 0.35
•  SVR and additionally coronary artery bypass grafting or mitral valve surgery if
clinically indicated.
•  Echocardiographic examination was performed before SVR and after 6 months
•  LV filling pressures increased significantly but did not have any
negative impact on clinical symptoms because most of the
patients showed an improvement in NYHA functional class and
exercise performance.
•  Therefore, the potential negative effects of increased LV filling
pressures after SVR are exceeded by the beneficial effects on LV
systolic function, resulting in improved clinical status
•  There are a number of inaccuracies and limitations associated
with the application of Laplace type calculations of LV wall stress
•  An inaccuracy specific to the Young-Laplace law is the restriction
the
Laplace
law(h)doesn’t
in human
hearts
that..the
wall
thickness
be very apply
much less
* than the
radius
like in solid
of curvature
(r). shapes:
Conclusions
•  Even the magnitude of stress calculated with the modified
Laplace law is very different than stress in the fiber and crossfiber directions calculated with the FE method.
•  As a consequence the Laplace law and the modified Laplace law
are inaccurate when used to calculate the effect of the Dor
procedure on regional ventricular stress.
•  The FE method is necessary to determine stress in the left
ventricle with postinfarct and surgical ventricular remodeling
•  40 patients: MRI before and after SVR
•  SVR reduces end-systolic wall
stress,
…BUT:
•  it does not succeed in restoring the
stress to normal values
•  is this sufficient to reverse
remodeling of border zone ?
•  significant improvements of systolic function after SVR,
…may be due to concurrent CABG
…and regarding the
selection criteria :
•  having an operative risk of less than 10% and an improvement
at 1 year in more than 80% of survivors, left ventricular
reconstruction is a therapeutic option superior to other
therapeutics
Ø  In the end-stage situation of an ischemic failing ventricle with
an asynergic scar of greater than 40% of the LV perimeter
•  Sufficient residual remote myocardium is necessary to
recover from a SVR procedure and to translate the
surgically induced morphological changes into a
functional improvement.
Ø  Preoperative WMSI is a surrogate measure
of residual remote myocardial function
Ø  Echocardiographic WMSI will help to
improve results after SVR procedures for
advanced ischemic heart failure
(in predicting mortality or poor functional
result: cutoff value: 2,19)
•  The survival benefits of this therapy are
significantly reduced by advanced HF at
baseline
ü NYHA functional class IV
ü large postsurgical LVESVI
(> 60 mL/m2).
•  These findings suggest that SVR might
be considered as a therapeutic option
for patients with HF in less-advanced
stages of the disease.
•  In these high-risk patients, SVR
successfully increased ejection fraction
and decreased symptoms.
Ø  A preoperative left ventricular
end-systolic volume index of
80 to 120 may be the ideal
range for SVR procedures..
…many problems
ü  we need to prove the
efficacy of surgical
therapy !
ü  we need to define the
proper indications !
ü  we need to establish the
technique and the
achievable targets !
fluid dynamic evaluation :
•  After the surgical procedure, washout was slightly lower (not
significantly different) compared with before SVR despite the
significant alterations in shape and fluid dynamics.
•  Our findings of similar fluid washout in the ball-shaped ventricle of the
patient after surgery despite changes in ejection fraction, shape, and
fluid dynamics may explain the fact that patients after SVR are not at
greater risk for thrombus formation than before.
•  The presented analysis describes an attractive tool to assess the fluid
patterns in the heart in patients with ischemic heart disease.
And looking the things from another
side, it’s noteworthy…:
•  Little is known about the changes in material properties that occur
as the infarct heals
•  We believe that increases in material compliance (reduction in
stiffness) that occur during infarct healing and maturation contribute
to the immediate and progressive loss of cardiac function
experienced by many patients after MI.
•  LV remodeling after MI is manifest by progressive LV dilatation,
reduction in EF, and increased filling pressures: one explanation for
this phenomenon based on our results would be that infarcts become
more compliant as they heal and mature.
•  Our results also support the potential therapeutic value of stiffening the
infarct as a means of preventing, limiting, or reversing LV remodeling
after MI.