Download Understanding the Pediatric Ventricular Assist Device

Understanding the Pediatric Ventricular Assist Device
W. James Parks, MSc., MD
Pediatric Cardiologist
Assistant Professor of Pediatrics and Radiology
Children’s Healthcare of Atlanta
Sibley Heart Center Cardiology
Emory University School of Medicine
Understanding the Pediatric Ventricular Assist Device
Introduction:
Mechanical devices used to support in part or in total, the circulatory
hemodynamics required to maintain or sustain the function of the
failing or compromised heart. Heart transplantation is today is an
increasingly common treatment for end-stage heart failure in all ages.
However, many candidates expire or are rendered non-candidates due
to the ravages of low cardiac output upon the body.
Background:
In patients, with severe heart failure prolonged periods of myocardial
unloading and support through the use of Ventricular Assist devices has
been shown to be critical in providing occasion for full functional
recovery or sustainable improvement. Support through the use of
these devices can increase the output of present myocardial effort and
inotrophic therapy. These devices can provide life sustaining output
and thus, critically needed time for recovery (‘bridge to recovery’),
analysis or donor (‘bridge to transplant’) procurement. In those not
considered candidates for additional surgery, it provides ‘destination
therapy’.
Intra-Aortic Balloon Pump:
A counterpulsation balloon synchronized to the EKG or arterial
waveforms. It reduces myocardial work through afterload reduction
and improves myocardial oxygen by augmentation of diastolic blood
pressure and coronary perfusion pressure.
Extracorporeal Membrane Oxygenation (ECMO):
ECMO remains the most often applied mechanical support for infants
and young children. Its problems related to anticoagulation and patient
bleeding, hematologic factor consumption, cannula and filter
thrombosis (dessiminated intravascular coagulation), and time
limitations restrict its use after only a few days or weeks. However,
now several continuous flow and pulsatile extracorporeal and
implantable assist devices are available for pediatric use. These devices
were developed specifically for pediatric patients with miniaturized
pumps and cannulas suitable for all pediatric patients including
neonates.
Continuous-Flow Left Ventricular Assist Device
A Pulsatile-Flow Left Ventricular Assist Device
Slaughter et al., Advanced Heart Failure Treated with Continuous-Flow LVAD
NEJM 361:23 Dec 3, 2009
I. Etiologies of Cardiac Failure: Indications for VAD
A. Cardiomyopathy (congenital or acquired)
B. Active myocarditis (infections)
C. Anomalous coronary arteries with severe nonrecoverable myocardial impairment
D. Post surgical heart failure (non-recoverable)
E. Congenital Heart Disease (10%, reportedly
uncorrectable)
F. Toxins
G. Tumors
H. etc.,
II. Ventricular Assist Devices (LVAD/RVAD/BiVAD):
The LVAD is used most commonly used ventricular support device
however, if pulmonary arterial resistance is high, right ventricular
assistance (RVAD) becomes necessary. The used of Bi-ventricular
(BiVAD) support is rarely necessary but is being used increasingly for
long-term support if needed in the Pediatric patient.
III. Needs / Requirements for success: Team Approach
IV. Reported Complications / Limitations:
A.
B.
C.
D.
E.
F.
G.
H.
Bleeding
Infection
C. Thrombo-embolic events
Right Heart Failure
Device Failure
Immunologic Effects and Allosensitization
Defects in cellular immunity
B-cell activation
V. Device Types and Reported Improvements:
A. Medtronic Biomedicus VAD: A ventricular assist device (VAD) for
pediatric patients less than five years of age. It is a short-term use nonpulsatile, centrifugal-flow system. It can support patients aged, five to
sixteen years.
B. The MicroMed DeBakey (VAD) Child: A long-term, non-pulsatile, axial
flow ventricular assist system. It is the first FDA approved device for use in
children.
C. The Berlin Heart: A long-term pulsatile ventricular assist device (VAD),
which can provide support of the left or right ventricle (LVAD/RVAD) or
serve as a biventricular device (BiVAD) in heart conditions that can no
longer be managed with medication therapy. This system is available in
four pump sizes for use infants and adult-sized patients. The Berlin Heart
has not received FDA approval, however its use has been allowed on a
case-by-case basis as it is one of the only proven long-term assist devices
available for use in infants and small children.
D. Thoratec paracorporeal VAD: Is used in adult-size patients for longterm, pulsatile-ventricular assistance. It is a versatile system which can also
provide left, right or biventricular support to adult-sized patients. This longterm device enables patient mobility and performance of many routine
activities as a bridge to recovery or transplantation.
E. Impella PERCUTANEOUS Left VAD: Is used in post cardiotomy shock. It is
smaller with low cost and easy to place without a teans-septal puncture.
F. Newer-generations and future:
Magnetic levitation technology with advanced energy system and smaller
control consoles. Incor Left VAD: accentuated axial flow pump.
Heartmate III: magnetically suspended centrifugal pump
VI. Contraindications:
VII. Device Components:
VIII. Surgical Techniques:
IX. Clinical Results:
X. Summary: