Lasers, Tights, and
Bayers…Oh My!!!: Part II
Dwight A. Dishmon, MD
Morbidity and Mortality Conference
April 6, 2006
Introduction
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There is an
increasing
population of
patients who have
persistent anginal
symptoms despite
maximal therapy
Following CABG,
only 75% of patients
are symptom free
from ischemic
events for 5+ years
and only 50% after
10+ years
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As the survival of patients with primary
coronary events continues to increase,
the number of patients with CAD
unsuitable to further revascularization
and symptoms refractory to medical
therapy also continues to rise
Enhanced external counterpulsation
(EECP) is one of the treatment
strategies that is finding a role in the
treatment of patients with refractory
angina
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EECP is a noninvasive outpatient
treatment used for intractable angina
EECP uses an acute hemodynamic
effect that is presumed to be similar to
that produced by the intra-aortic
balloon pump (IABP)
By applying a series of compressive
cuffs sequentially from the calves to the
thigh muscles upon diastole and rapidly
deflating the cuffs in early systole, an
increase in diastolic and decrease in
systolic pressure is created
History
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In 1953, Kantrowitz and Kantrowitz
initially described the concept of
diastolic augmentation as a technique
to improve coronary blood flow
Birtwell and others showed that the
ECG QRS complex could be used to
time an external pumping device that
provided a synchronous pulse wave
thereby increasing coronary collaterals
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Gorlin coined the term
“counterpulsation” to describe the twofold effect of the rapid displacement
and reduced resistance of volume in the
lower arterial circuit
Soroff and Birtwell first described how
the application of a positive pressure
pulse to the lower extremities during
diastole could raise diastolic pressures
by 40-50% and lower systolic pressures
by up to 30%
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In the 1960’s, S.D.
Malopoulis
developed an
experimental
protocol of the
IABP where a pulse
wave was delivered
via an intra-aortic
balloon device
timed to the
cardiac cycle
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By the early 1960’s, 3 groups
independently developed hydraulically
activated external couterpulsation
devices
Initial experience with a crude
external counterpulsation device used
in stable angina saw relief of angina
symptoms with angiographic
evidence of increased vascularity
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In the early 1980’s, a Chinese group lead byZ.S.
Zheng began using a sequential three cuff
external counterpulsation method
Their positive clinical experience led to the
installation of more than 1500 external
counterpulsation units in China
Technique
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EECP is offered exclusively by
Vasomedical Inc.
Involves the use of three paired
inflatable cuffs wrapped around the
patient’s lower extremities
The patient is connected to an ECG
monitor and a finger plethysmograph
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The R wave of the ECG is used as the trigger for
inflation and deflation
The cuffs are sequentially inflated (calves 
lower thighs  upper thighs) during diastole
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All pressure is released at the onset of
systole
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The diastolic augmentation increases
coronary perfusion pressure and
provides improved afterload reduction
and increased venous return
Systolic unloading is enhanced and
cardiac workload is decreased via
decrease in PVR
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Retrograde aortic pressure wave
 diastolic pressure
 intracoronary perfusion
pressure
 myocardial perfusion
 venous return
 preload
 cardiac output
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systemic vascular resistance
cardiac workload
myocardial O2 consumption
afterload
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Pressures in the range of 250-275
mmHg applied
Treatment course consists of 35 onehour sessions
Patient Selection
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Patients with angina or angina
equivalents who:
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No longer respond to medical therapy
Restrict their activities to avoid angina
Are unwilling to undergo addt’l procedures
Are high risk for revascularization
Have coronary anatomy unsuitable for
revascularization
Suffer with microvascular angina
Contraindications
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Arrhythmias that interfere with machine
triggering
Bleeding diathesis
Active thrombophlebitis
Severe lower extremity vaso-occlusive
disease
Presence of a documented aortic
aneurysm requiring surgical repair
Pregnancy
Precautions
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BP > 180/110 should be controlled
HR >120 bpm
Pulmonary congestion
Significant valvular disease
Mechanism of Action
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Several theories have been postulated
The hemodynamic effects of EECP have
been theorized to simulate the IABP
where CO, SV, and retrograde aortic
diastolic flow are enhanced and
myocardial O2 demand is decreased
Potential for increased transmyocardial
pressure to open collaterals
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In 1973, Banas demonstrated that EECP
increased angiographically visible
collateralization in patients with chronic
stable angina
It has been postulated that collateral
development is dependent upon the
patency of neighboring vessels
An open non-obstructed conduit
provides the milieu for greatest benefit
Huang, W, et al. J of Eur Soc of
Cardio. 1999.
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The less the CAD, the greater the therapeutic
benefit from EECP
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Michaels et al measured left ventricular
and intracoronary hemodynamics
directly in patients undergoing EECP
Aortic pressure, intracoronary pressure,
and intracoronary Doppler flow velocity
were measured at baseline and during
EECP
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93% increase in diastolic pressure
16% increase in mean intracoronary
pressure
15% decrease in systolic pressure
28% increase in coronary blood flow
Central aortic pressure
Intracoronary phasic and mean pressures
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Hemodynamic improvement in terms of
diastolic augmentation, improved
coronary perfusion and systolic
unloading are supplemented by
neurohormonal factors
Diastolic augmentation causes
increased shear stress  endothelial
growth factors  angiogenesis
Endothelial Cell
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With exposure to the augmented blood flow
and endothelial shear stress, there is
elaboration of NO, MMPs, and VEGF
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Masuda et al examined the effect of EECP on
the angiogenic factors
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Garlichs et al found that EECP reduced
serum endothelin-1 concentrations
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Masuda et al showed that EECP induced an
increase in concentrations of NO and a
decrease in BNP and ANP
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Within the endothelial cells, angiotensin II is
an oxidative stressor promoting superoxide
formation, NO degradation, and endothelial
dysfunction
Effects on Perfusion
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Lawson et al studied patients with
chronic stable angina and compared the
extent of CAD with results of
radionuclide stress testing after EECP
There was significant improvement in
the perfusion defects after EECP
The benefits were sustained at five
years’ follow-up which showed a
significant improvement in stress
thallium perfusion and limiting angina
“The Pressure”
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Suresh et al examined the optimal pressures
to maximize the hemodynamic benefit of
EECP
EECP effectiveness ratios (ratio between
diastolic augmentation and systolic
unloading) in the range of 1.5-2.0 were found
to be optimal
200 mm Hg pressure
ARTERY
% INCREASE IN FLOW
Left main coronary
18%
Carotid artery
19%
Vertebral artery
12%
Renal artery
21%
300 mmHg pressure
ARTERY
% INCREASE IN FLOW
Left main coronary
42%
Carotid artery
26%
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Another study analyzed the data from
an EECP registry examining the effect of
diastolic augmentation on the efficacy
of EECP
Patients with higher diastolic
augmentation tended to have a greater
reduction in angina class at 6 months
There is evidence that higher diastolic
augmentation ratios are associated with
improved short or long-term clinical
outcomes
Efficacy
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There are reported benefits derived
from the use of EECP
The first multicenter randomized shamcontrolled trial was the MUlticenter
STudy of Enhanced External
CounterPulsation (MUST-EECP)
MUST-EECP compared full EECP
treatment –vs- sham on exercise
treadmill scores and subjective angina
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In this trial conducted in 7 centers, 139
outpatients with angina, documented
CAD, and (+) ETT were randomly
assigned to receive 35 hrs of active or
inactive counterpulsation
59 patients in the active and 65 in the
inactive group completed the study
Outcome was measured in terms of
exercise duration, time to 1 mm ST
segment depression, avg daily anginal
attacks, and NTG use
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MUST-EECP was a small trial and was
not powerful enough to recommend
EECP for routine use
Follow-up analysis of patients in the
MUST-EECP trial at 1 yr showed greater
improvement in the health-related
quality of life measures in the active
treatment group
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In January 1998, Phase 1 of the
International EECP Patient Registry
(IEPR) was established to document
patient characteristics, safety, efficacy,
and long-term outcomes of EECP
therapy
Analysis of long-term outcomes
demonstrates that the clinical benefits
achieved with EECP are sustained up to
at least 24 months
More Studies…
In Summary…
References
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Sinvhal, RM, et al. EECP for Refractory
Angina Pectoris. Heart. Aug 2003.
Parmley, WW and Chatterjee, K.
Enhanced External Counterpulsation.
Cardiology Update. Oct 1997.
The Physician’s Guide to EECP Therapy.
Vasomedical Inc.
Masuda, D, et al. EECP Promotes
Angiogenesis Factors in Patients with
Chronic Stable Angina. Circulation.
2001.
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Quan, XX, et al. Effect of EECP on Nitric
Oxide Production in Coronary Disease. J
of Heart Disease. May 1999.
Werner, D, et al. Pneumatic External
Counterpulsation– A New Treatment for
Selected Patients with Symptomatic
CAD. Circulation supplement. Nov 1998.
Werner, D, et al. A New Noninvasive
Method to Improve Organ Perfusion.
Am J Cardio. 1999.