Invited Commentary

Abstract

Several factors have combined in recent years to increase the use of ventricular assist devices (VADs) in children. The development of pediatric-specific devices and the progressive miniaturization of adult devices (making them amenable to implantation in smaller and smaller children) have both had a significant impact on our ability to support children with heart failure. However, significant challenges remain in providing appropriate mechanical support across the range of patient sizes and clinical conditions seen in a children’s hospital. The ability of a device to support our smallest patients is an obvious problem. However, the difficulties presented in keeping multiple rarely used devices available at a children’s hospital also include financial constraints and maintaining training and competency of staff. It is often not viable to have every device that would be potentially useful immediately available. In this context, the current case series represents an important benchmark in the design, validation, and clinical use of an adapted adult VAD in the pediatric population. Kulat and colleagues [1Kulat B. Russell H.M. Sarwark A.E. et al.Modified TandemHeart ventricular assist device for infant and pediatric circulatory support.Ann Thorac Surg. 2014; 98: 1437-1442Abstract Full Text Full Text PDF Scopus (20) Google Scholar] should be commended for designing the adaptation of the TandemHeart (CardiacAssist, Inc, Pittsburgh, PA) device, testing its properties in an animal model, and then moving on to selected clinical patients. The specifics of their series provide an important option for short-term support of smaller pediatric patients, particularly at centers already facile in the use of the TandemHeart VAD in larger patients. Their design broadens the range of patients potentially supported by the TandemHeart, allowing it to be used as the primary temporary support option for infants through adults. There are some drawbacks to this application of the TandemHeart. The bridge and connectors may result in additional turbulence, and there is the potential for thrombus formation and hemolysis. Although the TandemHeart pump has a 10-mL prime volume (versus 14-mL in the PediMag pump; Thoratec, Pleasanton, CA), this advantage may be negated by the TandemHeart’s larger tubing and the prime volume of the bridge. The hydrodynamic bearing within the TandemHeart is designed to have a 10 mL/h infusion of heparinized saline, and although this volume is insignificant in adults, it may have important consequences in infants with heart failure. Thus despite the good outcomes, this setup has not been critically compared with other support options and should be approached cautiously—especially when support is required beyond 14 days. However, as pediatric mechanical support becomes more common, this case series demonstrates one solution to the challenge of providing support across a range of patient sizes. It reinforces the fact that each center must critically evaluate available options. Evaluation should include the risks and benefits of each device and the range of support provided (both in terms of patient size and duration). However, perhaps as important is ensuring that a center can support the broadest range of patients with the most medically appropriate and cost-effective combination of devices. As Kulat and colleagues [1Kulat B. Russell H.M. Sarwark A.E. et al.Modified TandemHeart ventricular assist device for infant and pediatric circulatory support.Ann Thorac Surg. 2014; 98: 1437-1442Abstract Full Text Full Text PDF Scopus (20) Google Scholar] demonstrate, this may require innovative solutions customized to the circumstances of each center. Modified TandemHeart Ventricular Assist Device for Infant and Pediatric Circulatory SupportThe Annals of Thoracic SurgeryVol. 98Issue 4PreviewThe development of pediatric ventricular assist device (VAD) circuits with lower flow ranges for infants and small children is ongoing. We present our results with modifying a readily available adult VAD to support the pediatric population. Full-Text PDF