Moving actuator type total artificial heart with reverse position of the aortic and pulmonary conduits

A strategy for designing of customized electromechanical actuators of blood pumps

Congestive heart failure is a pathology of global incidence that affects millions of people worldwide. When the heart weakens and fails to pump blood at physiological rates commensurate with the requirements of tissues, two main alternatives are cardiac transplant and ventricular assist devices (VADs). This article presents the design strategy for development of a customized VAD electromagnetic actuator. Electromagnetic actuator is a brushless direct current motor customized to drive the pump impeller by permanent magnets located in rotor-stator coupling. In this case, ceramic pivot bearings support the VAD impeller. Electronic circuitry controls rotation switching current in stator coils. The proposed methodology consisted of analytical numerical design, tridimensional computational modeling, numerical simulations using Maxwell software, actuator prototyping, and validation in the dynamometer. The axial flow actuator was chosen by its size and high power density compared to the radial flow type. First step consisted of estimating the required torque to drive the pump. Torque was estimated at 2100 rpm and mean current of 0.5 A. Numerical analysis using finite element method mapped vectors and fields to build stator coils and actuator assemblage. After tests in the dynamometer, experimental results were compared with numerical simulation and validated the proposed model. In conclusion, the proposed methodology for designing of VAD electromechanical actuator was considered satisfactory in terms of data consistency, feasibility, and reliability.

Korean artificial heart (AnyHeart): an experimental study and the first human application

A Korean artificial heart (AnyHeart) has been implanted in 29 various animals (52-470 kg) to evaluate hemodynamic performance and electromechanical stability. Most were implantable biventricular assist devices in use. A right thoracotomy approach has been a standard technique of implantation. A preclinical fitting test was also performed to observe anatomical feasibility and to compare surgical techniques in 10 human cadavers. The first case of human application was made as a lifesaving procedure on June 12, 2001.

Implantation of one piece biventricular assist device by left thoracotomy in an ovine model

In this report, we describe an operative procedure for our implantable 1 piece biventricular assist device (BiVAD) based on a moving actuator mechanism, using an ovine model. Our implantable BiVAD is a volumetric coupled 1 piece unit including right and left blood sacs and an actuator assembly based on the moving actuator mechanism. The BiVAD was controlled by fixed rate control with 75 bpm for the most part. Both the left and the right full ejection modes with the maximum stroke angle were selected to minimize blood stasis in the blood sacs because of low assist flow condition. Three Corriedale sheep were used for the device implantation by a left thoracotomy incision. Cannulation was successfully performed in all cases. Although exposability of the right atrial appendage varied from animal to animal, the insertion of the cannula was easily performed. The cannulas were connected to the pump-actuator assembly in the preperitoneal pocket. All 3 animals survived the experimental procedure. During implantation of the device, in the 1 month survival animal, pump flow was maintained between 2.0 L/min and 2.5 L/min, mean aortic pressure was 90-110 mm Hg, and mean pulmonary artery pressure was 20-30 mm Hg. The left and right atrial pressure were maintained between 0 and 5 mm Hg. In conclusion, this ovine model for implantation of the 1 piece BiVAD can be an effective alternative for testing in vivo biocompatibility of the device although it needs more consideration for anatomical fittability for future human application.