The DeltaStream blood pump has been developed for extracorporeal circulation with one focus on potential integration into simplified bypass systems (SBS). Its small size and an embedded electric motor are the basic pump properties. A variation of the impeller design has been performed to optimize hydraulic and hematologic characteristics. A simple impeller design was developed which allows flow and pressure generation for cardiopulmonary bypass applications. The option of a pulsatile flow mode for ventricular assist device applications also was demonstrated in vitro. Impeller washout holes were implemented to improve nonthrombogenicity. The pump was investigated for potential thermal hazards for blood caused by the integrated electric motor. It could be demonstrated that there is no thermal risk associated with this design. Durability tests were performed to assess the lifetime of the pump especially with regard to the incorporated polymeric seal. Seal lifetimes of up to 28 days were achieved using different blood substitutes. In animal tests using either the pump as a single device or in an SBS setup, biocompatibility, low hemolysis, and nonthrombogenicity were demonstrated. In summary, the DeltaStream pump shows great potential for different extracorporeal perfusion applications. Besides heart-lung machine and SBS applications, ventricular assist and extracorporeal membrane oxygenation up to several days also appear promising as potential applications.

Whereas circulatory support with pulsatile assist devices is an established therapy in adults today, it remains unusual and extremely challenging in children. Specifically designed smaller size pumps are, to date, only available in Europe. This review summarizes the experience with both adult size pumps in the U.S. and pediatric pumps in Europe. Thoratec ventricular assist devices (VADs) were implanted in 101 patients worldwide who were between 7 and 17 years of age. Survival in this group was 68.8%, which is comparable with that in adult patients and was independent of age or body size. Berlin Heart VADs, available in several sizes, were implanted at the Deutsches Herzzentrum Berlin in 45 patients between 2 days and 16 years old. Survival in patients with myocarditis and cardiomyopathy was 66.7% and 71.4%, respectively; overall survival was 48.9%. In a number of European centers, 64 children up to 16 years of age received Medos devices, which are also available in several sizes, with an overall survival of 36.2%, similar for all pump sizes. End-stage congenital heart defects or failure to wean off bypass carried a poorer prognosis than cardiomyopathies or myocarditis for all devices.

Mock loops are an important tool for in vitro investigations of artificial blood pumps. The simple windkessel, throttle, and atrium principle was used for the mock loop design presented. The components of the systemic and the pulmonary mock loop were designed according to calculated numerical simulation parameters. The loops offer a compact design and simple handling. For simulating biventricular assist or total artificial heart (TAH), both loops can be coupled correspondingly. The numerical simulation and the first results with the loops show very good similarity to physiological data of systemic and pulmonary circulation. The measurements of pump characteristics are significant for quantitative comparison of different pump sizes and types, or driving systems.

Today, rotary pumps are routinely used for extracorporeal circulation in different clinical settings and applications. A review of these applications and specific limitations in extracorporeal perfusion was performed and served as a basis for the development of the DeltaStream. The DeltaStreams is a miniaturized rotary blood pump of a new and unique design with an integrated drive unit. Despite its small design, the pump maintains a sufficient hydraulic capacity, which makes the DeltaStream very flexible for intra- and perioperative applications. It also opens the field for short-term ventricular assist devices (VAD) applications or use as a component in extracorporeal life support systems (ECLS). The DeltaStream and, specifically, its impeller design have been optimized with respect to haemolysis and nonthrombogenicity. Also, the pump facilitates an effective pulse generation in VAD applications and simulates heart action in a more physiological way than other rotary pumps or roller pumps. Hydraulic and haematological properties have been tested in vitro and in vivo. In a series of seven animal experiments in two different setups, the pump demonstrated its biocompatibility and applicability. Basic aspects of the DeltaStream pump concept as well as important console features are presented. A summary of the final investigation of this pump is given with focus on hydraulic capabilities and results from animal studies.

Since 1990, development of the Helmholtz-Institute at Aachen ventricular assist device (HIA-VAD) was mainly based on animal tests performed at the University of Groningen. Although various in vitro tests had been performed previously, animal testing resulted in significant improvements of the HIA-VAD with regard to hemodynamics and pump handling. The most important design improvement was a new trileaflet polyurethane valve, which was designed as a blood-pump valve with an emphasis on opening behavior and flow resistance. Excellent hydrodynamic performance and sufficient durability of this new valve were confirmed by various in vitro tests. Further design and manufacturing improvements resulted in a completely transparent pump, which can be easily deaired and optically controlled. Final pump design was evaluated during subsequent animal tests, and the results are very promising in view of an efficient cardiac support system.