Background
The use of ventricular assist devices (VADs) in children is challenging because of small patient size, frequent structural heart disease, and the need for biventricular assist devices. This report describes the role of echocardiography in the management of children supported by VADs.
Methods
A retrospective review of the records of all pediatric patients who underwent VAD placement between May 2005 and May 2011 was performed to collect demographics, cardiac diagnoses, details of VADs, and transthoracic and transesophageal echocardiographic findings from the time of initial diagnosis until VAD explantation.
Results
The study included 32 patients (median age, 3 years; age range, 20 days to 16 years; median weight, 12.3 kg; weight range, 3.5–60 kg), 20 with left ventricular assist devices and 12 with biventricular assist devices. Diagnoses included dilated cardiomyopathy or myocarditis ( n = 27) and congenital heart disease ( n = 5). The median duration of support was 12 days (range, 1–141 days). Patients with decreased right ventricular function were 8 times more likely to undergo biventricular assist device placement compared with those with normal right ventricular function ( P = .026). Pre-VAD intracardiac shunts were identified in 11 patients and intracardiac thrombus in one patient. Cardiac chamber dimensions and mitral insufficiency were significantly reduced after VAD implantation. Postimplantation pericardial effusions were recognized in 16 patients and pericardial hematomas in 12 patients.
Conclusions
Echocardiography is invaluable in the management of pediatric patients receiving VADs. It is helpful in pre-VAD assessment, guiding intraoperative device placement, recognizing VAD dysfunction, and identifying postimplantation complications.
Since their introduction for clinical use in the 1980s, ventricular assist devices (VADs) have been increasingly used to treat advanced heart failure both as a bridge to cardiac transplantation (or recovery) and as destination therapy. On the basis of its success in the adult population, this technology has increasingly been extended to pediatric patients. The use of VADs in children is more complicated because of the much wider patient size range, the presence of important congenital heart disease, and frequent need for biventricular assist devices (BiVADs). Until recently, the only VAD approved by the US Food and Drug Administration for use in small children was the DeBakey VAD Child (MicroMed Technology Inc., Houston, TX). However, this device has not gained widespread acceptance, because of significant thromboembolic complications. Moreover, its use is restricted to children aged > 5 years, with body surface areas > 0.7 m 2 . The Berlin Heart EXCOR VAD (Berlin Heart AG, Berlin, Germany) was developed in Germany in the early 1990s and was first used in North America in 2000. It is currently the most commonly implanted pediatric-specific VAD and was recently approved by the Food and Drug Administration after the conclusion of a successful trial performed under investigational device exemption regulations.
Echocardiography is the most commonly used imaging technique before, during, and after VAD implantation. The purpose of this study was to review our institutional experience with the use of echocardiography in the management of pediatric patients with Berlin Heart VAD and to introduce a protocol for echocardiographic assessment of VADs in pediatric patients.
The Berlin Heart EXCOR Device
The EXCOR device is a pneumatically driven, pulsatile VAD system that is available for either left ventricular (LV) or biventricular support. The system consists of a paracorporeal blood pump with inflow and outflow valves, which is attached to the circulatory system by inflow and outflow cannulas that traverse the body wall. Cannulas and blood pumps are available in a range of sizes allowing support in children as small as 3 kg, up to adult-sized teenagers. Cannulation for LV support involves the placement of an outflow cannula in the ascending aorta and an inflow cannula in the LV apex, although left atrial (LA) inflow cannulation is also feasible. Right ventricular (RV) support is accomplished by means of an inflow cannula placed in the right atrium and an outflow cannula placed in the pulmonary artery ( Figure 1 ).
