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MYOCARDIAL RECOVERY
MECHANICAL DEVICES TO
AID RECOVERY
Stephen Westaby
Oxford, UK
POST INFARCTION CARDIOGENIC
SHOCK
 Occurs in 10% of myocardial
infarction patients
 Mortality is 50-60% despite
aggressive medical therapy
 Effectively reperfused and potentially
recoverable patients still die through
myocardial stunning (35% mortality
in the “SHOCK” Trial)
PREDICTION OF CARDIOGENIC SHOCK
IN THE CARDIAC CATHETERISATION
LABORATORY
 Poor coronary reperfusion (TIMI Grade <3)
 Left main coronary occlusion
 Left ventricular ejection fraction <25%
 Age >75 years
 All with 2 of the 4 risk factors died.

Garcia-Alverez A et al. Am j Cardiol 2009; 103:1073-77
OUTLOOK FOR SURVIVORS OF
CARDIOGENIC SHOCK
GUSTO:
88% of those discharged from
hospital are alive at one year
SHOCK:
3 and 6 year survival 79%
and 62%
Around 50% of patients remain free from
heart failure symptoms.
The Damaging Effects of High Dose
Inotropes
 Elevated stroke work and wall tension.
 Increased myocardial oxygen consumption.
 Depletion of energy reserves.
 Endocardial necrosis & impaired diastolic
function.
 Overall negative effect on myocardial
recovery.
IABP - why use it?
 Increase coronary perfusion pressure
 Increase myocardial oxygen supply
without increasing demand
 Decrease afterload and MVO2
 But increase in cardiac output is only
0.5-0.8 L/min
Does not increase survival in post
infarction cardiogenic shock
POST INFARCTION CARDIOGENIC
SHOCK
 Can ventricular assist devices
improve survival?
 Does evidence exist to
demonstrate improved survival?
The Rationale for Recovery in the
Unloaded Myocardium
 The failing heart beats > 120, 000 times per day
and pumps > 6000 litres of blood against an
increasing afterload.
 As the heart dilates wall tension, myocardial
energy and oxygen consumption increase. Sub
endocardial blood flow decreases.
 An unloaded heart has the chance of recovery; a
heart left supporting the circulation does not.
What Does An LVAD Do?
 Provides 3-7 litres systemic blood flow.
 Reverses the acute or chronic heart failure
syndrome.
 Reduces left ventricular work and increases
coronary blood flow.
 Increases right ventricular work (tolerated in
95%).
 Promotes improvement in myocardial function
at cellular and metabolic level.
LVAD in cardiogenic shock
MYOCARDIAL ENERGY CONSUMPTION
Modified from Allen BS, Rosenkranz ER, Buckberg GD et al
J Thorac Cardiovasc Surg 1986;92:543-552
ACCEPTED CRITERIA FOR LVAD
DEPLOYMENT
 Cardiac index <2.0L/min.m2
 Systolic blood pressure <90 mm Hg
 Pulmonary capillary wedge pressure >20 mm Hg
 Rising creatinine and liver transaminases
 Patient oliguric, acidotic with cool extremities
and obtunded mental state.
TANDEM HEART IN ACUTE MI
Removes Oxygenated blood from LA via transseptal
cannula inserted through the femoral vein
Returns blood via femoral artery
Pre
Post
CO
3.5
4.8
BP (mean)
63
82
PAP
31
23
PCWP
20
14
All p<0.001
*Thiele H, Laver B, Hambrecht R, Boudriot I, Cohen H, Schuler G. Reversal of
cardiogenic shock by percutaneous left atrial to femoral arterial bypass
assistance. Circulation 2001; 104:2917-22.
Bridge to myocardial recovery
with the AB 180 implantable
centrifugal pump - 1997
Alive with normal
cardiac function –
2010
The Impella
system in
cardiogenic
shock.
Improves
haemodynamics.
As yet no survival
benefit.
The Levitronix Centrimag VAD
The Levitronix® CentriMag VAS is designed
to provide temporary support for patients
suffering potentially reversible cardiogenic
shock.
CE approved for up to 30 days of use.
Phaeochromocytoma
myocarditis
Ruptured
mycotic
aneurysm
of the left
ventricle
15 year old female
with staphylococcal
septicaemia and
mitral valve
endocarditis
MINI–ECC TRANSPORT FROM AFGHANISTAN
Surgery with Mini-ECC
Case:
 Male 58 years
 Coronary dissection in
cath lab
 cardiogenic shock
 → Stabilisation and
Transport
 → CABG with Mini-ECC
Cardiohelp
Portable VAD and oxygenator for cardiogenic shock or respiratory failure
Before committing the patient to short
term circulatory support, the team
should have realistic expectations of a
satisfactory end point
 Recovery from stunning, infarction or myocarditis.
 Availability of a donor heart within weeks.
 An opportunity to convert to a long term LVAD
Myocardial pathology is unpredictable. Bridge
to decision making is a reasonable first step.
LVAD IN POST INFARCTION
CARDIOGENIC SHOCK
 An LVAD will sustain systemic blood flow
and prevent organ dysfunction whilst the
reperfused myocardium recovers from
stunning.
 Clinical trials of IABP versus LVAD support
are underway. Hemodynamic parameters
strongly favour the LVAD but survival
advantage is yet to be proven.