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ICDs – Primary prevention
The EP Show:
Which ICD for which patient?
Part 2: Primary prevention
Eric Prystowsky MD
Director, Clinical Electrophysiology Laboratory
St Vincent Hospital
Indianapolis, IN
Helmut Klein MD
Head of Division of Cardiology
Otto-von-Guericke Universität Magdeburg
Magdeburg, Germany
Paul Dorian MD
Professor of Medicine
Division of cardiology
St Michael's Hospital
Toronto, ON
EP Show – Aug 2003
ICDs – Primary prevention
Major trials
Primary prevention patients
MUSTT:
• CAD
• EF <40%
MADIT I:
• CAD
• EF <35%
MADIT II:
• CAD
• EF <30%
EP Show – Aug 2003
ICDs – Primary prevention
ICD benefit
2-year all-cause mortality (%)
40
Relative reduction
31%
51%
54%
Control
30
ICD
20
10
0
MADIT II
EP Show – Aug 2003
MUSTT
MADIT I
ICDs – Primary prevention
MUSTT
Entry Criteria
• EF <40%
• CAD
• Spontaneous nonsustained
ventricular tachycardia (VT-NS)
Total mortality (5 years)
ICDs
(n=161)
Drug therapy
(n=153)
p
24%
55%
<0.001
EP Show – Aug 2003
Buxton et al. N Engl J Med
1999;341(25):1882-90.
ICDs – Primary prevention
ICD benefit
2-year all-cause mortality (%)
40
Relative reduction
31%
51%
54%
Control
30
ICD
20
10
0
MADIT II
EP Show – Aug 2003
MUSTT
MADIT
ICDs – Primary prevention
Nonischemic
Control
ICD
All-cause mortality
(%)
14
12
10
8
6
4
2
0
EP Show – Aug 2003
CAT
AMIOVERT
ICDs – Primary prevention
Two questions
Why has it not been possible to show a
survival benefit with ICDs for nonischemic
cardiomyopathy patients?
Why haven't more ICDs been used in primary
prevention in light of the positive data from
trials?
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Nonischemic sudden death
The mechanism for sudden death may not be
the same in nonischemic patients; they are
less likely to have a new ischemic event
The intermediate term prognosis for
nonischemic patients seems to be better
• Arrhythmia mechanisms may be
different
• Beta blockers may be more effective
• ICDs may give less "bang for the buck"
EP Show – Aug 2003
ICDs – Primary prevention
Jury is still out
"We have to be very careful to
remember that absence of proof is not
the same as proof of absence."
It is not yet proven that patients with
dilated cardiomyopathy benefit from ICDs
as primary prophylaxis, but [there is] also
no proof ICDs are useless in this population
Numerous upcoming trials may shed further
light on the issue
Dorian
EP Show – Aug 2003
ICDs – Primary prevention
Primary prevention
"Clearly we don't know everything we
need to know about the magnitude of
benefit from implanted defibrillators"
Few doubt ICDs are effective
The question is the likelihood of a patient
actually suffering sudden death
• If small, the overall benefit is small
• If large, the overall benefit is large
EP Show – Aug 2003
Dorian
ICDs – Primary prevention
Insurance metaphor
A wood house heated by coal or wood
needs good fire insurance, while a brick
house not heated often doesn't need fire
insurance
"How likely do we think it is that
patients at potential risk for sudden
death will actually have ventricular
defibrillation or VT and be rescued by
their defibrillator?"
Dorian
EP Show – Aug 2003
ICDs – Primary prevention
CMS decision
CMS did a subgroup analysis of MADIT II to
give only partial coverage of ICDs—similar
to the house metaphor
With limited resources one must pick the
patients who clearly will get the most
benefit
"If defibrillators cost a buck a piece,
we wouldn't have the argument."
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
ICDs in Europe
Why are there different approaches to ICDs
in Germany and France?
"It's more a philosophic issue than a
medical issue."
"It doesn't make sense that there is a
difference between France and
Germany and Italy; I cannot explain
this."
Klein
EP Show – Aug 2003
ICDs – Primary prevention
Nonischemic cardiomyopathy
The progress of nonischemic cardiomyopathy
is very difficult to predict
Patients with long-lasting nonsustained VT
have a worse prognosis
We tend to give long-lasting nonsustained VT
patients ICDs, even when they are
nonischemic
• A personal opinion
EP Show – Aug 2003
Klein
ICDs – Primary prevention
Need more parameters
More parameters [are needed] to judge risk
in nonischemic patients because they have a
high risk of sudden death
There is the parameter of nonsustained VT
indicating higher risk
Klein
EP Show – Aug 2003
ICDs – Primary prevention
Primary prevention
So far in Germany, any patient meeting the
criteria have received an ICD, but this is
changing toward a more careful husbanding
of resources
"We have had no problems so far, but
it's getting worse and we will probably
be forced to do so."
Klein
EP Show – Aug 2003
ICDs – Primary prevention
CMS coverage
CMS decided to provide reimbursement for
patients with MADIT II criteria but only
those with a QRS duration of >120 ms
"Frankly, having reviewed the data in
the literature so far, that does seem to
at least be the wood house. It doesn't
mean we shouldn't be protecting the
nonwooden houses."
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Optimal therapy
"We believe strongly that patients
should be considered for prophylactic
ICD if and only if their other therapies
have been absolutely optimized."
In a practical sense, this means many
patients recommended for ICDs are ruled
out by this more stringent approach
Dorian
EP Show – Aug 2003
ICDs – Primary prevention
MIRACLE
End point
Quality-of-life
score
NYHA class
Change in 6minute walk
distance (m)
Control
group
95% CI
CRT
group
95% CI
p
-11.0
-16 to -7
-17.5
-21 to -14
0.02
0
-1 to 0
-1
-1 to –1
0.007
53
43 to 75
55
44 to 79
0.36
Young JB et al. JAMA 2003; 289:2685-2694.
EP Show – Aug 2003
ICDs – Primary prevention
COMPANION
Relative reduction at 12 months:
compared with control arm
Measure
Mortality and
hospitalization
Mortality
EP Show – Aug 2003
CRT (%)
19
CRT-ICD
(%)
19
23.9
43.4
ACC 2003
ICDs – Primary prevention
Biventricular ICD
COMPANION showed that
resynchronization improves quality of life
and performance, but only the defibrillator
improves the survival
"You cannot prevent sudden death by
just improving ventricular function. . . . And
if I have to make the choice, I certainly
would use the combined device in coronary
artery disease patients."
Klein
EP Show – Aug 2003
ICDs – Primary prevention
Biventricular pacemakers
"I have yet to implant a biventricular
pacemaker [for this group of people]."
The data showing an advantage in
preventing sudden death with the ICD
function are very clear
"Am I just being too aggressive?"
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Changing approach
"Our thinking has evolved in this
topic."
We started doing a number of pacemakeronly devices, but evidence is mounting that
improving ventricular function has only
modest effects in preventing arrhythmia
The extra risks and costs of adding the ICD
function are not dramatic, and we are
implanting more biventricular ICDs
Dorian
EP Show – Aug 2003
ICDs – Primary prevention
Choosing patients
Patients who clearly are in severe heart
failure despite optimal medical treatment
we tend to give biventricular ICDs
Those who have QRS of 120 or so but no
severe heart failure might not get the ICD
function
Klein
EP Show – Aug 2003
ICDs – Primary prevention
The broader view
"It's important to not just see the data
as they are published but also to be
able to put them in context with a
world of experience."
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Secondary prevention
Patients with documented cardiac arrest,
sustained VT, syncope in the EP lab
Randomized trials point toward ICDs as
therapy for these patients
DAVID trial suggests not pacing the
ventricle, selecting which device is left to
the physician
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Primary prevention
Randomized trials show that in ischemic
heart disease ICDs are the best choice for
therapy
For the nonischemic patients, the data are
still not in and more data are needed
Depending on your budget, how narrow
your selection process is will vary
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
Biventricular devices
The biventricular ICD prolongs life, not just
a biventricular pacemaker
The selection for a given patient will
depend on multiple factors
There are still situations where a doctor or
investigator may pick a biventricular
pacemaker only
Prystowsky
EP Show – Aug 2003
ICDs – Primary prevention
The EP Show:
Which ICD for which patient?
Part 2: Primary prevention
Eric Prystowsky MD
Director, Clinical Electrophysiology Laboratory
St Vincent Hospital
Indianapolis, IN
Helmut Klein MD
Head of Division of Cardiology
Otto-von-Guericke Universität Magdeburg
Magdeburg, Germany
Paul Dorian MD
Professor of Medicine
Division of cardiology
St Michael's Hospital
Toronto, ON
EP Show – Aug 2003