Clinical outcomes in pediatric patients implanted with Thoratec ventricular assist device

Pediatric ventricular assist devices: what are the key considerations and requirements?

Introduction: The development of ventricular assist devices (VADs) have enabled myocardial recovery and improved patient survival until heart transplantation. However, device options remain limited for children and lag in development.Areas covered: This review focuses on the evolution of pediatric VADs in becoming to be an accepted treatment option in advanced heart failure, discusses the classification of VADs available for children, i.e. types of pumps and duration of support, and defines implantation indications and explantation criteria, describes attendant complications and long-term outcome of VAD support. Furthermore, we emphasize the key considerations and requirements in the application of these devices in infants, children and adolescents.Expert opinion: Increasing use of VADs has facilitated a leading edge in management of advanced heart failure either as a bridge to transplantation or as a bridge to myocardial recovery. In newborns and small children, the EXCOR Pediatric VAD remains the only reliable option. In some patients ventricular unloading may lead to complete myocardial recovery. There is a strong need for pumps that are fully implantable, suitable for single ventricle physiology, such as the right ventricle.

Intensive care of the pediatric ventricular assist device patient

Utilization of ventricular assist devices (VADs) in children is increasing, as is the complexity of patients supported. We review the intensive care management of pediatric patients with VAD in the perioperative and rehabilitation phases, highlighting the technical aspects and physiology of VADs which impact care. Indications for VAD placement and the preoperative assessment of risk are discussed. Specific aspects of postoperative and long-term care including device troubleshooting, hemostasis and anticoagulation, support of the right ventricle, incidence and prevention of neurologic injury, and other complications are reviewed.

Pediatric Ventricular Assist Devices: The Future (as of 2011)

In the last decade, there have been enormous advances in the field of pediatric-specific mechanical circulatory support. In the past, small children requiring bridge to transplant or recovery were limited to extracorporeal membrane oxygenation. Now, in various stages of development, there are several devices that offer the promise of the same quality of support enjoyed by older teenagers and adolescents, with the potential to substantially reduce transplant waiting list mortality and optimize transplant outcomes. Advances have been driven by both industry and, for the first time, by funding from the US National Institutes of Health.

Waiting list mortality among children listed for heart transplantation in the United States

BACKGROUND

Children listed for heart transplantation face the highest waiting list mortality in solid-organ transplantation medicine. We examined waiting list mortality since the pediatric heart allocation system was revised in 1999 to determine whether the revised allocation system is prioritizing patients optimally and to identify specific high-risk populations that may benefit from emerging pediatric cardiac assist devices.

METHODS AND RESULTS

We conducted a multicenter cohort study using the US Scientific Registry of Transplant Recipients. All children <18 years of age who were listed for a heart transplant between 1999 and 2006 were included. Among 3098 children, the median age was 2 years (interquartile range 0.3 to 12 years), and median weight was 12.3 kg (interquartile range 5 to 38 kg); 1294 (42%) were nonwhite; and 1874 (60%) were listed as status 1A (of whom 30% were ventilated and 18% were on extracorporeal membrane oxygenation). Overall, 533 (17%) died, 1943 (63%) received transplants, and 252 (8%) recovered; 370 (12%) remained listed. Multivariate predictors of waiting list mortality include extracorporeal membrane oxygenation support (hazard ratio [HR] 3.1, 95% confidence interval [CI] 2.4 to 3.9), ventilator support (HR 1.9, 95% CI 1.6 to 2.4), listing status 1A (HR 2.2, 95% CI 1.7 to 2.7), congenital heart disease (HR 2.2, 95% CI 1.8 to 2.6), dialysis support (HR 1.9, 95% CI 1.2 to 3.0), and nonwhite race/ethnicity (HR 1.7, 95% CI 1.4 to 2.0).

CONCLUSIONS

US waiting list mortality for pediatric heart transplantation remains unacceptably high in the current era. Specific high-risk subgroups can be identified that may benefit from emerging pediatric cardiac assist technologies. The current pediatric heart-allocation system captures medical urgency poorly. Further research is needed to define the optimal organ-allocation system for pediatric heart transplantation.

Anatomic fit assessment for the Penn State pediatric ventricular assist device

This investigation determined the ages and weights of children that could be supported with 12 and 25 ml Penn State pediatric ventricular assist devices (PVADs) using 6, 8, and 10 mm outlet cannulas and grafts. Future patients will be matched to devices based on cardiac output (CO) and ascending aortic diameter (AA). These were calculated for children 0-10 years with regression formulas given as clinical standards [<5 kg, CO = 0.2171(kg) + 0.0703], [>5 kg, CO = 3.06 (m2) + 0.37], [AA = -0.0427 + 14.54 (m2)1/2]. The 12 ml PVAD will be useful for patients from approximately birth to 3-8 months, weighing 2-7 kg, and having 0.5-1.4 L/min CO; the 25 ml PVAD will be for children 2-6 months to 5-9 years old, weighing 6-23 kg, and having 1.3-3.0 L/min of CO. The 6 mm outlet graft will fit children from 0 to 12 months, weighing 2-8 kg; the 8 mm graft from 0 to 47 months, weighing 4-14 kg; and the 10 mm graft for children 4 months to 8 years, weighing 8-21 kg.

Matching the Mechanical Circulatory Support Device to the Child With Heart Failure

A number of mechanical circulatory support devices are currently available for the treatment of children with heart failure refractory to medical therapy. Patient size, the acute versus chronic nature of the heart failure that is present, and the underlying anatomy and physiology define the clinical setting in any given case. Determining which device most effectively meets the specific needs of the clinical setting requires an understanding of the characteristics of each of the available devices. This report describes a graphic representation of the clinical setting in which pediatric heart failure occurs to provide a decision-making framework for the selection of the most appropriate mechanical circulatory support device.