Ventricular Assist Devices: Evolution

1. Raja Lahiri

2.  A ventricular assist device (VAD) is an
electromechanical device for assisting
cardiac circulation, which is used either to
partially or to completely replace the
function of a failing heart.

3.  VADs are designed to
 assist the right ventricle (RVAD)
 the left ventricle (LVAD)
 assist both ventricles (BiVAD).

4.  Acute cardiogenic shock
 Bridge to transplant (BTT)
 Bridge to decision
 Destination therapy (DT)

5.  Acute cardiogenic shock after AMI
 Post cardiotomy cardiogenic shock
 Cardiogenic shock from Myocarditis
 Refractory ventricular arrhythmias

6.  Short term v/s Long term
 Para corporeal v/s Intra corporeal
 Pulsatile v/s Continuous flow
 Full assist v/s Partial assist
 Assist device v/s Total artificial heart

7.  The first successful
implantation of a left
ventricular assist
device was completed
in 1966 by Dr. Michael
E. DeBakey to a 37-
year-old woman with
post cardiotomy shock
following aortic valve
replacement.
 A paracorporeal
(external) circuit was
able to provide
mechanical support
for 10 days after the
surgery

8.  Dr. Denton Cooley reported the first
successful bridging to transplant using
mechanical support in 1978
 The first successful implantation of a heart
replacement therapy, the TAH Jarvik-7-100
was reported in 1984
 The first successful long-term implantation
of an artificial LVAD was conducted in 1988
by Dr. William F. Bernhard of Boston
Children's Hospital Medical Center and
Thermedics, Inc, which later led to the
development of Heartmate

9.  Randomized Evaluation of Mechanical
Assistance for the Treatment of Congestive
Heart Failure (REMATCH) trial aimed to
determine the suitability of LVAD for
destination therapy.
 In the trial, pulsatile-flow LVAD (HeartMate
XVE, Thoratec, Pleasanton, Calif.) was
compared to optimal medical therapy (OMT),
with the primary endpoint being all-cause
mortality.

10.  The trial showed that LVAD was associated
with a 48% reduction in mortality as
compared with OMT
 The survival at 1 year in the LVAD group was
52% as compared to 25% in OMT
 Published in 2007, the INTrEPID trial, also
showed a significant survival advantage with
LVAD for destination therapy in patients with
inotrope-dependent heart failure, as
compared to OMT
 In 2009, the HEARTMATE II trial reported
compared the newer continuous-flow LVAD
(HeartMate II) with pulsatile-flow LVAD. The
study reported that continuous-flow LVAD
was associated with increased probability of
2-year survival free from disabling stroke and
LVAD failure

11.  Mechanical circulatory support (MCS) can be
considered in selected patients with stage D HFrEF
with planned definitive management (eg, cardiac
transplantation) or cardiac recovery planned. (Class
IIa, Level B)
 Nondurable MCS is reasonable as a “bridge to
recovery” or “bridge to decision” for selected
patients with HFrEF with acute, profound
hemodynamic compromise. (Class IIa, Level B)
 Durable MCS is reasonable to prolong survival for
selected patients with stage D HFrEF (Class IIa, Level
B)
 Selection criteria for patients include: LVEF<25% and
NYHA class III-IV despite optimal medical therapy, and
either high predicted 1- to 2-year mortality (eg,
markedly reduced peak oxygen consumption and
clinical prognostic scores) or dependence on
continuous parenteral inotropic support

12.  Improves arterial blood pressure
 Improves end organ perfusion
 Decreases LVEDP as blood is directed towards
LVAD
 Decreases intracavitory pressure leading to
reduced myocardial oxygen consumption
 Reduces LA pressure thus decreasing
pulmonary congestion and prevents right
ventricular failure
(Even in the presence of LVAD, if refractory RVF develops:
RVAD may be used)

13.  Complexity
 Expensive (upto 90 lakhs)
 Open surgery: morbidity & mortality
 Surgical expertise required

14.  Short term:
 IABP
 ECMO
 Levitronix CentriMag
 Abiomed BVS 5000 & AB5000
 Abiomed Impella
 TandemHeart

15.  Long term:
 FIRST GENERATION: (Centrifugal & Pulsatile flow)
 Thoratec HeartMate XVE
 Thoratec paracorporeal VAD
 Thoratec Intracorporeal VAD
 SECOND GENERATION: (Axial Flow)
 Thoratec HeartMate II
 Jarvik 2000
 MicroMed DeBakey
 Incor Berlin Heart
 THIRD GENERATION: (Axial Flow)
 VentraCor VentrAssist
 Terumo DuraHeart
 WorldHeart LevaCor
 Thoratec HeartMate III
 HeartWare
 CircuLite Synergy

16.  Kantrowitz in ‘68
 Most commonly
used
 Used in
 High risk PCI
 Post AMI- ACS
 Post MI- MR/VSD
 Cardiotomy shock
 Pre-op for CABG
 Counterpulsation
 Risk of vascular
complications

17.  For both
circulatory &
respiratory failure
 VV or VA
 Centrifugal pump
with oxygenator
 High
anticoagulation
requirement
 Limited durability

18.  Extracorporeal
centrifugal pump
 FDA approved for
upto 6 hrs
 Less hemolysis &
chances of
mechanical failure
 Upto 10L/min,
priming vol: 31ml
 Routine cannulation
can be used

19.  Dual chambered
pneumatically
driven
extracorporeal
pump
 Flow: 6L/min
 Initially FDA
approved for post
cardiotomy shock
 Easy to insert &
manage

20.  Next gen device
after BVS 5000
 Fully automated
 Vacuum asisted
console
 Increased patient
mobility
 Increased duration
of support

21.  Minimally invasive
assist device
 Inserted
percutaneously
through femoral
artery upto Left
ventricle
 2.5L/min flow with
partial support
 Impella recover LP
5.0 inserted upto
aorta & can provide
flow upto 5L/min
 Most commonly for
high risk PCI

22.  Percutaneously
inserted
 Inflow through
femoral vein from
LA; Outflow into
femoral artery
 Flow rates upto 4
L/min @7500rpm
 Easy to insert:
popular in high risk
PCI & post MI shock

23.  FDA approved both for
BTT & DT
 Electronically vented,
portable console &
batteries
 Pusher plate
technology: pulsatile
flow
 SV=83ml, Flow 10L/min
 Two mode: fixed & auto
 In electronic failure:
can be pneumatically
driven with a hand
pump
 No anticoagulation, only
aspirin

24.  For Univentricular &
Biventricular support
 Paracorporeal
placement allows
implantation in pt
with BSA<1.5m2
 Pulsatile flow: SV-
65ml, max flow-
7.2L/min
 Requires less
dissection
 Inflow from LA/LV
Apex/RA/RV; Outflow
to Aorta/Pulm Artery

25.  Similar to
paracorporeal
device in
applications
 Requires more
dissection
 First FDA approved
implantable BiVAD
for BTT & post
cardiotomy shock

26.  Axial flow rotary
pump
 Smaller, less invasive
 Flow 10L/min @ 6k-
15k rpm
 Inflow: LV Apex
 Outflow: Ascending
aorta
 Small pocket for
housing in
preperitoneal space
 FDA approved for BTT

27.  Electromagnetically
actuated
 2.5cm diameter,
weight: 90gms
 Displacement: 25ml
 Flow: 7L/min @ 8k-
12k rpm
 Actual pumping
chamber in LV
 Can be implanted
through left
thoracotomy

28.  In collaboration with
NASA
 Wt: 95gms
 Size: 3”x1.2”
 Flow: 10L/min
 Single percutaneous
driveline
 Anticoagulation
required
 High incidence of
stroke and embolism
reported
 FDA approved for use
in children as BTT

29.  MagLev axial flow
pump
 Wt:200gm;3cm dia
 Impeller
magnetically
levitated: hence
not in contact with
any other part
 7L/min @ 10k rpm

30.  Centrifugal pump
with hydrolytically
suspended motor
 No need for
anticoagulation
 Wt:300gms, 2.5”
dia
 82% success as BTT

31.  Magnetic
Levitation
technology
 Flow: 2-8L/min @
1200-2400rpm
 In case of
magnetic failure,
the impella can be
levitated
hydrolytically

32.  Magnetically
levitated
centrifugal pump
 Specially devised
for pediatric age
group

33.  Magnetically
levitated
centrifugal
impeller
 Transcutaneous
energy transfer
system for battery
charging
 Totally
implantable

34.  Centrifugal pump
with no mechanical
bearings
 Wt: 145gm, SV: 45ml,
Flow: 10L/min @ 2k-
3k rpm
 Inflow cannula
integrated into LV
 Implanted in
pericardial space
 Single flexible 4.2mm
dia driveline exits
anterior abdominal
wall

35.  Can be placed
intrvascularly
 Inflow in LA
(through
subclavian vein),
outflow in
subclavian artery
 Partial support
device

36.  Patient classification:
 Acute cardiogenic shock
 May or may not have Multi Organ Failure
 Neurological status may or may not be known
 CHF listed for heart transplantation
 Bridge to transplant (BTT) candidates
 Other CHF patients
 Non transplant candidates
 Not yet evaluated for transplant
 Potentially recoverable myocardium
 Candidates for destination therapy (DT)

37.  Patients in Cardiogenic Shock
 Abiomed BVS 5000
 Abiomed AB 5000
 CentriMag
 BiVAD
 Decompresses both ventricles
 Restores hemodynamic stability
 Provides enhanced peripheral perfusion
 Prevents end organ dysfunction
 Decreases the requirement of pressors as
inotropes viz. milrinone can be stopped

38.  BTT
 FDA has approved HeartMate II for BTT
 Better than HM I
 Smaller
 Quieter
 Low incidence of infection
 Decreased incidence of device malfunction
 Bridge to recovery/decision
 CentriMag
 Can switch to long term device or explant as per
need
 DT
 HeartMate XVE is the only FDA approved device
for DT
 HM II & VentraCor VentrAssist are being
evaluated
 Both are smaller, comfortable and long lasting

39.  Skin Incision
 Creation of preperitoneal pocket
 Mediastinal exposure
 Cannulation of the aorta and venous system
 Going on CPB
 Outflow graft anastomosis to ascending aorta
 Coring of LV, placing core sutures & inserting
inflow core into LV apex
 De-airing the device
 Weaning off CPB, actuating LVAD
 Hemostasis & Closure

41.  Early post-op:
 Antibiotics: from pre-op to atleast 3 days post-op
 RHF treated with Milrinone, Dobutamine and
Nitric Oxide
 NE or Vasopressin for vasodilator hypotension
 Amiodarone & Lidocaine for ventricular
arrhythmias
 Late post-op:
 Early ambulation & rehabilitation
 Monitoring signs of infection
 Discharge f/b weekly follow-up for atleast a
month

42.  Anticoagulation:
 HeartMate I XVE: does not require
anticoagulation
 HM II, VentraCor & Thoratec Intra and Para
corporeal VAD: VKA + antiplatelets
 Anticoagulation & Antiplatelets avoided in the
first 48 hrs

43.  Bleeding
 Platelets, FFP, Cryoprecipitate, Factor VII
 Infection
 Sepsis in 11-26% leading to 21-25% deaths
 Thromboembolism(7-47%)
 HM XVE has lowest incidence (2-3%)
 Device Malfunction
 Right Heart Failure
 20% incidence; Mx: diuresis, NO, inotropes, RVAD
 Multisystem Organ Failure
 11-29% of VAD deaths; usually pre-exisiting