Apical aortic blood pump preclinical assessment for long­term use: durability test and stator topology to reduce wear in the bearing system

This study presents an assessment for long­term use of the apical aortic blood pump (AABP), focusing on wear reduction in the bearing system. AABP is a centrifugal left ventricle assist device initially developed for bridge to transplant application. To analyze AABP performance in long­term applications, a durability test was performed. This test indicated that wear in the lower bearing pivot causes device failure in long­term. A wear test in the bearing system was conducted to demonstrate the correlation of the load in the bearing system with wear. Results from the wear test showed a direct correlation between load and wear at the lower bearing pivot. In order to reduce load, thus reducing wear, a new stator topology has been proposed. In this topology, a radial stator would replace the axial stator previously used. Another durability test with the new stator has accounted twice the time without failure when compared with the original model.

Apical aortic blood pump preclinical assessment for long-term use: Durability test and stator topology to reduce wear in the bearing system.

This study presents an assessment for long-term use of the apical aortic blood pump (AABP), focusing on wear reduction in the bearing system. AABP is a centrifugal left ventricle assist device initially developed for bridge to transplant application. To analyze AABP performance in long-term applications, a durability test was performed. This test indicated that wear in the lower bearing pivot causes device failure in long-term. A wear test in the bearing system was conducted to demonstrate the correlation of the load in the bearing system with wear. Results from the wear test showed a direct correlation between load and wear at the lower bearing pivot. In order to reduce load, thus reducing wear, a new stator topology has been proposed. In this topology, a radial stator would replace the axial stator previously used. Another durability test with the new stator has accounted twice the time without failure when compared with the original model.

Specification of supervisory control systems for ventricular assist devices.

One of the most important recent improvements in cardiology is the use of ventricular assist devices (VADs) to help patients with severe heart diseases, especially when they are indicated to heart transplantation. The Institute Dante Pazzanese of Cardiology has been developing an implantable centrifugal blood pump that will be able to help a sick human heart to keep blood flow and pressure at physiological levels. This device will be used as a totally or partially implantable VAD. Therefore, an improvement on device performance is important for the betterment of the level of interaction with patient's behavior or conditions. But some failures may occur if the device's pumping control does not follow the changes in patient's behavior or conditions. The VAD control system must consider tolerance to faults and have a dynamic adaptation according to patient's cardiovascular system changes, and also must attend to changes in patient conditions, behavior, or comportments. This work proposes an application of the mechatronic approach to this class of devices based on advanced techniques for control, instrumentation, and automation to define a method for developing a hierarchical supervisory control system that is able to perform VAD control dynamically, automatically, and securely. For this methodology, we used concepts based on Bayesian network for patients' diagnoses, Petri nets to generate a VAD control algorithm, and Safety Instrumented Systems to ensure VAD system security. Applying these concepts, a VAD control system is being built for method effectiveness confirmation.

Specification of supervisory control systems for ventricular assist devices

One of the most important recent improvements in cardiology is the use of ventricular assist devices (VADs) to help patients with severe heart diseases, especially when they are indicated to heart transplantation.TheInstitute Dante Pazzanese of Cardiology has been developing an implantable centrifugal blood pump that will beable to help a sick human heart to keep blood flow and pressure at physiological levels. This device will be used asa totally or partially implantable VAD. Therefore, an improvement on device performance is important for thebetterment of the level of interaction with patient’s behavior or conditions. But some failures may occur if the device’s pumping control does not follow the changes in patient’s behavior or conditions. The VAD control system must consider tolerance to faults and have a dynamic adaptation according to patient’s cardiovascular system changes, and also must attend to changes in patient conditions, behavior, or comportments. This work proposes anapplication of the mechatronic approach to this class of devices based on advanced techniques for control, instrumentation, and automation to define a method for developinga hierarchical supervisory control system that is able to perform VAD control dynamically, automatically, andsecurely. For this methodology, we used concepts based on Bayesian network for patients’ diagnoses, Petri nets to generate a VAD control algorithm, and Safety Instrumented Systems to ensure VAD system security. Applying theseconcepts, a VAD control system is being built for method effectiveness confirmation.