Platelet activation after implantation of the Levitronix PediVAS in the ovine model.

The Levitronix PediVAS is an extracorporeal magnetically levitated pediatric ventricular assist system with an optimal flow rate range of 0.3-1.5 L/min. The system is being tested in preclinical studies to assess hemodynamic performance and biocompatibility. The PediVAS was implanted in nine ovines for 30 days using either commercially available cannulae (n = 3) or customized Levitronix cannulae (n = 6). Blood biocompatibility in terms of circulating activated platelets was measured by flow cytometric assays to detect P-selectin. Platelet activation was further examined after exogenous agonist stimulation. Platelet activation increased after surgery and eventually returned to baseline in animal studies where minimal kidney infarcts were observed. Platelet activation remained elevated for the duration of the study in animals where a moderate number of kidney infarcts with or without thrombotic deposition in the cannulae were observed. When platelet activation did return to baseline, platelets appropriately responded to agonist stimulation, signifying conserved platelet function after PediVAS implant. Platelet activation returned to baseline in the majority of studies, representing a promising biocompatibility result for the Levitronix PediVAS.

Pre-clinical Implants of the Levitronix PediVAS® Pediatric Ventricular Assist Device - Strategy for Regulatory Approval.

The PediVAS blood pump is a magnetically levitated centrifugal pump designed for pediatric bridge-to-decision or bridge-to-recovery in pediatric patients from 3-20kg in weight. In preparation for submission of an investigational device exemption (IDE) application, we completed a final six-animal series of pre-clinical studies. The studies were conducted under controlled conditions as prescribed by the recently released FDA guidance document for animal studies for cardiovascular devices. Three 30-day chronic left ventricular support studies were completed in a juvenile lamb model to demonstrate the safety and hemocompatibility of the PediVAS pump. Three additional 8-hour acute biventricular support studies were performed to demonstrate the feasibility of this approach from a hemodynamic and systems standpoint. It is estimated that 50% of pediatric patients who require left ventricular support also require right ventricular support. All studies were successfully completed without complications, device malfunctions, or adverse events. End-organ function was normal for the chronic studies. We noted small surface lesions on one kidney from each chronic study as well as the presence of ring thrombus on connectors, as expected for these types of studies in animal models. The strategy and challenges imposed by performing a controlled cardiovascular device study in a juvenile lamb model are discussed. We believe that these successful implants demonstrate safety and performance for the PediVAS device for support of an IDE application to initiate human clinical trials and provide a roadmap for other researchers.

Assessment of hydraulic performance and biocompatibility of a MagLev centrifugal pump system designed for pediatric cardiac or cardiopulmonary support.

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the PediVAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to (1/4) in. For the expected range of pediatric flow (0.3-3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future.