Page 6 - VAD Guidelines

Pediatric Ventricular Assist Device (VAD) Guidelines

When to consider VAD support
VAD implantation should be considered when medical management is failing to maintain adequate
circulation. Clearly this is the case in cardiogenic shock but VAD support should also be considered when
heart failure requires:
• More than one high dose inotrope
• End-organ dysfunction
• Need for persistent mechanical ventilation
In some instances a VAD may be useful in severe feeding intolerance or failure to thrive despite optimal
oral and inotropic therapy.

Device Terminology
Paracorporeal (previously known as Extracorporeal) mechanical circulatory support devices provide
support through a pump mechanism and housing that remains outside the body. These devices vary
from traditional extra corporeal membrane oxygenator (ECMO) to pulsatile (Berlin) and continuous flow
(PediMag, CentriMag) devices. The devices require ongoing, inpatient management making hospital
discharge not feasible. Paracorporeal devices can be further subdivided into those referred to as
“temporary devices” (PediMag, CentriMag), based on FDA approval for device support lasting <72 hours,
and durable devices (Berlin). Trends in device subtype usage in pediatrics are aimed at optimizing
patient outcomes through advancements in technology, however, have led to an increasingly blurred
distinction between “temporary” and durable support.
Intracorporeal VADs provide support through a pump mechanism and housing contained within the
thoracic or intrapericardial space while pump control and power supply modules remain outside the
body communicating through a percutaneous driveline. These devices are similarly subdivided into
“temporary” (Impella) and durable support systems based on intended/approved duration of support.
Durable devices are further subdivided into intrapericardial, continuous flow devices (HeartWare,
HeartMate 3, and Jarvik 2015) and intra-thoracic pulsatile devices (Syncardia). Though the mechanism
of support differs between these durable devices, all represent the potential for hospital discharge on
device support.
Ventricular assist devices vary by the mechanism of support; pulsatile or continuous. Blood flow in a
pulsatile device is facilitated by a pneumatically driven membrane leading to filling and ejection of the
device. Continuous flow devices achieve blood flow through either an axial mechanism where blood
flow is in parallel to the device impeller (Impella, Jarvik 2015) or centrifugal mechanism where blood
flow is orthogonal to the device impeller (CentriMag, PediMag, HeartWare, HeartMate 3). Fluid
dynamics and pump function differ considerably between continuous flow mechanisms with the most
clinically important difference being centrifugal flow devices are significantly afterload sensitive.

VAD Device Types & Selection
There are now many devices available. Device selection is dependent upon several factors including
patient size, cardiovascular anatomy/physiology, degree of acute cardiovascular instability, need for
biventricular versus isolated sub-pulmonic or systemic ventricular support, and likelihood of cardiac
recovery. Two devices are intended to be deployed in acute settings (ECMO, Impella) while the
remaining devices including PediMag, CentriMag, Berlin, Heartware (HVAD), Heartmate 3 and Syncardia
require multidisciplinary planning. The Berlin Heart EXCOR is no longer the preferred device for support
related to poor outcomes in single ventricle (SV) and small (<10 kg) patient populations as well as an
unacceptable adverse event profile as compared to continuous flow devices. However, this device may
still be used in circumstances as deemed appropriate by the multidisciplinary VAD team.

Updated 3/24/2019 page 6