Towards the Development of a Pediatric Ventricular Assist Device

Abstract

The very limited options available to treat ventricular failure in children with congenital and acquired heart diseases have motivated the development of a pediatric ventricular assist device at the University of Pittsburgh (UoP) and University of Pittsburgh Medical Center (UPMC). Our effort involves a consortium consisting of UoP, Children's Hospital of Pittsburgh (CHP), Carnegie Mellon University, World Heart Corporation, and LaunchPoint Technologies, Inc. The overall aim of our program is to develop a highly reliable, biocompatible ventricular assist device (VAD) for chronic support (6 months) of the unique and high-risk population of children between 3 and 15 kg (patients from birth to 2 years of age). The innovative pediatric ventricular assist device we are developing is based on a miniature mixed flow turbodynamic pump featuring magnetic levitation, to assure minimal blood trauma and risk of thrombosis. This review article discusses the limitations of current pediatric cardiac assist treatment options and the work to date by our consortium toward the development of a pediatric VAD.

Platelet Activation in Ovines Undergoing Sham Surgery or Implant of the Second Generation PediaFlow Pediatric Ventricular Assist Device

“…Ventricular assist devices (VADs) have demonstrated a significant survival benefit, reduction in morbidity, and enhanced quality of life in adults with end stage heart failure [6-8]. The success of VADs in adults make these devices an attractive treatment modality for children suffering with congenital and/or acquired cardiac disease, however there is a dearth of such therapy options for infants and young children [2-5, 9]. This situation provided the impetus for the implementation of the United States National Heart, Lung, and Blood Institute’s Pediatric Circulatory Support Program [2].…”

“…This situation provided the impetus for the implementation of the United States National Heart, Lung, and Blood Institute’s Pediatric Circulatory Support Program [2]. As part of this program the PediaFlow™ device, a maglev turbodynamic VAD, is currently under development with an objective of providing bridge to transplant circulatory support for newborns and small children at a flow rate range of 0.3 to 1.5 L/min [5, 9-10]. The second generation prototype of the PediaFlow VAD (PF2; shown in Figure 1) was able to achieve higher flow rates than our first generation PediaFlow VAD through supercritical operation by utilizing a more efficient 4-pole motor.…”

Simple surface modification of a titanium alloy with silanated zwitterionic phosphorylcholine or sulfobetaine modifiers to reduce thrombogenicity

“…This surface has relevance for a number of cardiovascular devices, particularly in the rotary blood pump field where there is interest in extending this type of device therapy to the pediatric population [22]. In the present study, we focused on developing a simple modification method to covalently attach hemocompatible moieties onto a TiAl 6 V 4 surface in a process that would be amenable to complex surfaces such as one would encounter in a rotary blood pump.…”

Surface modification of a titanium alloy with a phospholipid polymer prepared by a plasma-induced grafting technique to improve surface thromboresistance

“…The composition of the biomaterial surface, the nature of the blood flowing across the device surfaces and the bias of the patient’s blood toward hemostatic reactions all combine to define thrombotic and thromboembolic risk. Thus much work has focused on utilizing computational fluid dynamics to improve flow characteristics over biomaterial surfaces in circulatory support devices [1] and similarly there has been great interest in developing chemical modifications for blood contacting surfaces [2]. …”

“…For design and machinability considerations the titanium alloy TiAl 6 V 4 makes up the blood contacting surfaces of this pump as well as several other rotary blood pumps in clinical use and in pre-clinical development [1,3–9]. Although titanium and its alloys have exhibited generally acceptable biocompatibility in a variety of settings, its surface modification remains of interest for blood contact since platelet deposition still can occur in vitro and thrombosis and thromboembolism can occur in these devices in vivo [10–12].…”