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©2015 MFMER |
Coronary
Revascularization
and the Bad LV
Implications of the STICH
Trial Substudy
Is the concept of
viability testing still
viable ?
ACC New York 2016 3492638-7
Is s
©2015 MFMER |
Prognosis of PatientsWith LV Dysfunction and CAD
Results of revascularization – a paradox
Periproceduralrisk Late mortality
Severity of LV dysfunction
Severity of CAD/ischemia
Major determinants
Pt with LV dysfunctionPt with CAD
3411890-9
©2016 MFMER |
STICH Trial – 10-Year Outcomes1,212 Pts (EF 0.35)
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8 9 10 11
Velasquez: NEJM, 2013
Even
t ra
te (
%)
Death from Any Cause (Primary
Outcome)
Years since randomization
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8 9 10 11
Death from Cardiovascular
Causes
Years since randomization
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8 9 10
Death from Any Cause or
Cardiovascular Hospitalization
Years since randomization
Med
CABG
Hazard ratio, 0.84(95% CI, 0.73-0.97)
P=0.02 by log-rank test
Med
CABG
Hazard ratio, 0.79(95% CI, 0.66-0.93)
P=0.006 by log-rank test Med
CABG
Hazard ratio, 0.72(95% CI, 0.64-0.82)
P<0.001 by log-rank test
3587177-02
NNT –14
©2016 MFMER |
Mechanisms of Improved Prognosis Following Revascularization – ?
Prevention
of ventricular
arrhythmias
Inducible ischemia
and repetitive stunning
Ventricular remodeling
in resting LVEF
Recovery in regional function
Potential
benefits
Diastolic dysfunction
Symptoms of CHF
? Benefits independent of effects on ischemia & viability but prevention of recurrent events
3587177-01
©2015 MFMER |
Definition of Viable Myocardium
3432359-5
Myocardium that is dysfunctional at rest and not scarred and has the potential for
functional recovery
Shah: EHJ, 2013
“Hibernation’ should be used retrospectively
only to describe those segments which
actually improve following revascularization
Before Surgery – LVEF = 26%
After Surgery – LVEF = 45%
©2015 MFMER |
Viability and Prognosis in Patients with LV Dysfunction
3432775-9
Different Substrates
• Hibernation (resting ischemia)
• Repetitive stunning (inducible ischemia)• Extent of scar• Extent of remodeling• Duration of hibernation
“How much is enough – not an all or none issue”
Need for combined imaging approaches to
characterize substrates and reversibility
©2014 MFMER |
Quantity of Viable Myocardial Required to Improve Survival With Revascularization in
Patients With Ischemic Cardiomyopathy
• 29 studies
• 4,167 patients
• Meta-analysis
3362090-4
25.8
35.938.7
0
10
20
30
40
50
PET Stress Echo SPECT
% V
iable
/tota
l m
yocard
ium
Optimal Threshold for Presence of Viability
Inaba: J NuclCardiol, 2010
©2015 MFMER |
Clinical Indications for Viability Testing
• Subtotal occlusions
• Collaterals
Patients with CAD and severe
LV dysfunction (EF 0.35)
“Flash” pulmonary
edema with subsequent
improvement
Clinical EF?
Severe CAD and no history of MI
Absent Q waves on ECG
Significant angina or stress-induced ischemia
Angiography
3471328-3
©2013 MFMER |
STICH – Myocardial Viability and Survival
3309958-10
0.0
0.2
0.4
0.6
0.8
1.0
0 1 2 3 4 5 6
601 pt – viability
testing
SPECT
DSE
Years since randomization
Pro
bab
ilit
y o
f d
eath
Hazard ratio 0.64
95% CI 0.48-0.86
P=0.003
Without viability (114 pt)
With viability (487 pt)
Bonow: NEJM, 2011
©2016 MFMER |
Subgroup No. Deaths HR (95% CI) P
Without 114 58 0.70 (0.41-1.18) NSviability
With 487 178 0.86 (0.64-1.16) NSviability
STICH – Myocardial Viability and Survival
359768-1
0.25 0.50 1.0 2.0
CABG better
Medical therapy better
Bonow: NEJM, 2011
©2015 MFMER |
“If you are not confused
by this – you are not
thinking clearly.”
Pogo
3492638-8
©2016 MFMER |
STICH Viability StudyLimitations
• Study is underpowered
• Non-randomized – viability performed at physician discretion and unblinded
• Baseline differences between pt with/without viability testing – comorbidities
• Viability determined in a binary fashion – PET and CMRI – greater accuracy and provide additional information
• Does not distinguish between dysfunctioning potentially viable myocardiumand reversibility
• 3 VD only present in approximately one third
• 85% of patients in substudy – non-USA
• Generalizability to contemporary populationICD – 50%
CRT – 20%
3507142-12
©2016 MFMER |
Not Essential
• Significant angina
• Good distal vessels
• ECG
• Reasonable surgical risk
3507142-13
Role of Viability Testing in Clinical Decision Making in Patients With LV Dysfunction
No Q waves
Preserved voltage
Potentially Helpful
• Severe LV dysfunction
• Extensive LV remodeling
• Multiple comorbidities
• Incomplete revascularization is likely
• Angina – less severe
©2013 MFMER |
Inducible Myocardial Ischemia andOutcomes of Revascularization
Panza: JACC, 2012
• STICH Trial
• EF <0.35
Stress testing
• Inducible ischemia 64%
• % ischemic myocardium (18±11%)
No Ischemia
Years following randomization0 1 2 3 4 5 6
Ischemia
Years following randomization0 1 2 3 4 5 6
MED (56 events)
CABG (47 events)
1.0
0.8
0.6
0.4
0.2
0.0
Mortality
Mort
alit
y r
ate
MED (31 events)
CABG (22 events)
3267767-3
©2014 MFMER |
Impact of Ischemia and Scar on Therapeutic Benefit from Coronary Revascularization
Lo
g h
aza
rd r
atio
Hachamovich: EHJ, 2011
Total myocardium ischemic (%)
-0.5
0.0
0.5
1.0
1.5
0.0 12.5 25.0 37.5 50.0
Medical therapy
Early revascularization
• % ischemic myocardium = P=0.089
• Ischemia treatment interaction = P=0.489
Role of ischemia in pt with >10% fixed myocardial
defect
• 13,969 pt
• Adenosine orexercise SPECT
P<0.001
3357109-17
©2014 MFMER |
Impact of Ischemia and Scar on Therapeutic Benefit from Coronary Revascularization
Lo
g h
aza
rd r
atio
Hachamovich: EHJ, 2011
Total myocardium ischemic (%)
-0.5
0.0
0.5
1.0
1.5
0.0 12.5 25.0 37.5 50.0
Medical therapy
Early revascularization
Role of ischemia on benefit of revascularization was nullified by presence of extensive infarction/scar
• 13,969 pt
• Adenosine orexercise SPECT
P<0.001
3391078-6
©2015 MFMER | 3485852-8
But CABG does improve angina symptoms compared withmedical therapy alone”
“Presence of angina does not confer markedly worse prognosis or a greater benefit from revascularization by CABG
Jolicouer et al
©2015 MFMER |
• No effect of viability, inducible ischemia and angina on surgical outcomes
• remodeling with non-viability but no effect on surgical outcomes
Is There a Role for Viability and Ischemia Testing? Is the Concept Still Valid and Rational?
3485205-06
Bonow: NEJM, 2011; Panza: JACC, 2012
Jolicouer: JACC, 2015; Bonow: JACC, 2015
No Yes
STICH patientsOther patient
subgroups
©2015 MFMER | 3459251-4
In patients with LV dysfunction and CAD, are the presence of viability, inducible ischemia and angina still therapeutic targets?
YES
Considerations
Viability and Ischemia Extent of scar and
remodeling
What is the point of no return?
©2015 MFMER |
• May influence response to medical therapy
Role of Viability TestingConclusions
• May predict response to revascularization in selected pts with CAD and LV dysfunction
• Impact of viability and residual ischemia may be overwhelmed by extensive scar and remodeling.
• Marker of prognosis
3493400-10
• Should “not” be a routine determinant of decision to revascularize
©2015 MFMER |
“The reports of my
death are greatly
exaggerated.”
Text of a cable sent by Mark Twain
from London to the press in the U.S.
after his obituary had been
mistakenly published
3492638-7