Background-The purpose of this study was to evaluate the acute in vivo pump performance of a unique valveless, sensorless, pulsatile, continuous flow total artificial heart (CFTAH) that passively self-balances left and right circulations without electronic intervention.

Cleveland Clinic’s continuous-flow total artificial heart has one motor and one rotating assembly supported by a hydrodynamic bearing. The right hydraulic output is self regulated by passive axial movement of the rotating assembly to balance itself with the left output. The purpose of this article is to present progress in four areas of development: the automatic speed control system, self-regulation to balance right/left inlet pressures and flows, hemolysis testing using calf blood, and coupled electromagnetics (EMAG) and computational fluid dynamics (CFD) analysis. The relationships between functions of motor power and speed, systemic flow, and systemic vascular resistance (SVR) were used for the sensorless speed control algorithm and demonstrated close correlations. Based on those empirical relationships, systemic flow and SVR were calculated in the system module and showed good correlation with measured pump flow and SVR. The automatic system adjusted the pump’s speed to obtain the target flow in response to the calculated SVR. Atrial pressure difference (left minus right atrial pressure) was maintained within ± 10 mm Hg for a wide range of SVR/PVR (systemic/pulmonary vascular resistance) ratios, demonstrating a wide margin of self-regulation under fixed-speed mode and 25% sinusoidally modulated speed mode. Hemolysis test results indicated acceptable values (normalized index of hemolysis <.01 mg/dL). The coupled EMAG/CFD model was validated for use in further device development.

The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices.

The PediPump is a passive magnetic bearing, mixed flow, rotary ventricular assist device designed to provide support for the entire range of patient sizes encountered in pediatrics. Blood enters axially at the inlet and is accelerated and turned in the impeller to exit the pump at an intermediate angle. The size of the PediPump facilitates standard cannulation strategies with substantially downsized components. The program pursues three specific objectives: 1) System engineering: Progress within the last year has focused on the assembly and testing of PediPump prototypes. Initial in vitro hydraulic performance and hemolysis testing were judged satisfactory. 2) Anatomic fitting studies: As part of the PediPump program, three-dimensional modeling techniques based on routine, clinically obtained computerized tomography (CT) scans have been developed. During 2006, the same techniques developed for clinical scans were applied to CT scans obtained from sheep to guide the presurgical planning. 3) Animal studies: Animal implantation of PediPump prototypes commenced in July 2006. A total of four 6 hour acute studies were performed throughout the remainder of the year. In vivo performance was satisfactory and compared well with the in vitro results. Hemolysis levels were low.

The PediPump is a small ventricular assist device (VAD) with a hydraulic output range designed to support children from newborns to adolescents. The present report describes our initial evaluation of the PediPump as a left VAD in an acute sheep model. The PediPump was implanted in two sheep (50.8 and 62.7 kg). Pump speed was adjusted to achieve a flow of 2 L/min with the naturally occurring preload and afterload conditions to evaluate pump performance under a steady hemodynamic state for 4 hours. Upon completion, pump performance was evaluated under various blood pressure and heart rate conditions. During steady-state evaluations, the ascending aortic flow and pump speed varied slightly depending on systemic arterial pressure variations. During the hemodynamic manipulation studies, flows ranged between 0.5 and 3.2 L/min with pump speeds of 5,200-16,200 rpm and motor current of 0.06-0.75 A. The PediPump demonstrated good initial hemodynamic performance for use as an implantable left VAD. However, some depositions were detected at the time of explanation, mainly at the rear of the pump. We are continuing with further acute studies to evaluate pump performance in anticipation of beginning chronic studies to evaluate long-term biocompatibility.

Our aim was to evaluate the potential use of BioMedFlex® (BMF), a new resilient, hard-carbon, thin- film coating, as a blood journal bearing material in Cleveland Heart’s continuous-flow left and right ven- tricular assist devices (VADs). BMF is not classified as a diamond-like carbon (DLC) and differs from other thin-film carbon coatings by its high flexural strength, radiopacity, and wear resistance. A 2- to 4-μm-thick BMF adhesion layer was deposited on the VAD journal bearing surfaces. A commercial DLC coating used in other clinical blood pump applications was used as a control. Durability and reliability of the BMF coating was verified in severe pump start/stop testing using 20 BMF-coated journal bearing pairs. The BMF-coated surfaces showed no coating failures, whereas 57% of the DLC bearing pairs developed scratches through the carbon coating, documenting that BMF can provide a durable coating in our blood journal bearing application. In conclusion, BMF has shown qualities that support its significant advantages as an alternative journal bea- ring material in Cleveland Heart pumps. Our plan includes biocompatibility testing with ongoing animal studies, endurance testing with submerged pumps running in saline, and assessment of batch coating processing capability

Introduction Paediatric plaque psoriasis (PedPso) in children and adolescents is often diagnosed and treated for the first time by paediatricians. An early onset of psoriasis is associated with a genetic family burden, higher severity of disease and increased risk of comorbidities, sometimes starting in childhood. However, little information is available on prevalence data and the clinical management of PedPso by paediatricians. Methods A total of 191 questionnaires were sent out to paediatricians regarding their management of PedPso, with a focus on prevalence, diagnosis, initiation of therapies, screening for comorbidities and collaboration with dermatologists. Of these, 95 (49.7%) were returned and evaluated anonymously. Results Only about one-half of the responding paediatricians reported being certain in their diagnosis of PedPso, even though they regularly see moderate-to-severely affected patients. The questionnaire revealed that there are clear differences in the general management of PedPso if the paediatrician is not certain of the diagnosis of psoriasis. Compared to paediatricians certain of their diagnosis, those who are uncertain less frequently perform whole-body inspection, screen for relevant comorbidities, such as psoriasis arthritis, metabolic syndrome or mental disorders, and prescribe the use of topical or systemic therapies. No responding paediatrician reported the use of modern systemic therapies, such as biologicals, even in severely affected children. The majority of respondents rated their cooperation with dermatologists as good. Conclusion The certainty of the diagnosis, the use of system therapies and the screening for comorbidity could improve the care of PedPso through targeted training of paediatricians and intensified interdisciplinary cooperation with dermatologist. Electronic supplementary material The online version of this article (10.1007/s13555-020-00390-y) contains supplementary material, which is available to authorized users.

This paper presents a novel stressing technique for investigating via quality and integrity in tungsten-AICu interconnect systems. This stressing technique induces a new manifestation of the stress induced voiding failure mechanism for a tungsten-AICu interconnect system. This voiding is caused by the cycling of the mechanical stress at the tungsten-metal interface. This mechanical stress cycling results from the Joule heating induced by the AC current stress. Finite element analysis numerical simulations were performed, and the simulated mechanical stress results correlated well to physical failure analysis results. The interaction of these mechanical stresses with localized aberrations in interfacial quality causes the metal voiding to occur. It will be demonstrated that utilizing cleaner ILD and metal etching techniques will reduce the failure rate due to this mechanism.