Kiyotaka Fukamachi

Was not provided for this article.

Unbalanced pressures and volumes between the right and left atrium will cause systemic and/or pulmonary congestion. The continuous-flow (CF) total artificial hearts (TAHs) developed at the Cleveland Clinic mitigate pressure imbalance by titrating right pump output via pressure-related changes in rotor axial position. Hall effect sensors were placed and calibrated at both ends of the pediatric CF TAH (P-CFTAH) stator bore to track the rotor’s permanent magnet location. The P-CFTAH was placed on a mock loop in water/glycerin, where several hemodynamic conditions, both pulsatile flow (PF) and CF, were tested while recording both left and right atrial pressures (LAP and RAP), outlet pressures (aortic pressure [AoP] and pulmonary artery pressure [PAP]), flows, and Hall effect sensor output. There was a positive correlation of ≥0.80 ( p < 0.0001) between rotor position and flow, and a negative correlation of ≥−0.80 ( p < 0.0001) between rotor position and atrial balance, systemic vascular resistance (SVR), and LAP. The rotor’s maximum movement per cycle during pulsatile testing was 1.32 mm, and the minimum was 0.51 mm, indicating a significant positive correlation (≥0.80; p < 0.0001) with pulse pressure and flow pulse. The passive balancing features of P-CFTAH are effective across a range of steady-state conditions.

Background: In patients with biventricular heart failure, a biventricular assist device (BVAD) may be necessary for hemodynamic support. BVAD inflows can be established through cannulation of the atrial (AC) and/or ventricular (VC) chambers, but no consensus exists on optimal cannulation techniques. This study aimed to characterize BVAD performance related to cannulation types (AC and VC) using a continuous‐flow total artificial heart (CFTAH) as the BVAD. Methods: Both methods of cannulation (AC and VC) were tested on a mock loop using dual pulsatile ventricles with valves (AB5000; Abiomed) paired as the native ventricles and a double‐ended centrifugal pump with two volutes, CFTAH, as a BVAD. Pressures were collected at the inlet and outlets of the AB5000 (LAP, RAP, AoP, and PAP) and the CFTAH (Lin, Rin, Lout, and Rout). The left and right flows exiting the CFTAH (LPF and RPF) and total flow (TF), exiting systemic resistance, were monitored. Several heart failure conditions were simulated with adjustment of the pneumatic pressures (AB5000). Results: Trends between the AC and VC are similar where RAP, Lin, and Lout decreased, and AoP, PAP, TF, LPF, and RPF increased with increased support. The trends differ in LAP with an increase during AC as opposed to a decrease during VC. As a result, with this setup, left–right balance is more easily achieved during VC. TF is higher with AC, even though LPF and RPF are lower. This signifies the flow going through the aortic valve (TF–LPF) and pulmonary valve (TF–RPF) is higher with AC. Conclusions: The increased TF and valvular flow favored AC for introducing a CFTAH as BVAD to the native heart in these conditions.

Cleveland Clinic’s continuous-flow total artificial heart (CFTAH) is being developed at our institution and has demonstrated system reliability and optimal performance. Based on the results from recent chronic in vivo experiments, CFTAH has been revised, especially to improve biocompatibility. The purpose of this article is to report our progress in developing CFTAH. To improve biocompatibility, the right impeller, the pump housing, and the motor were reviewed for design revision. Updated design features were based on computational fluid dynamics analysis and observations from in vitro and in vivo studies. A new version of CFTAH was created, manufactured, and tested. All hemodynamic and pump-related parameters were observed and found to be within the intended ranges, and the new CFTAH yielded acceptable biocompatibility. Cleveland Clinic’s continuous-flow total artificial heart has demonstrated reliable performance, and has shown satisfactory progress in its development.

BackgroundThe objective of this study was to assess the pulsatility preservation capability of the universal ventricular assist device (UVAD) when used as a biventricular assist device (BVAD). This evaluation was conducted through an in vitro experiment, utilizing a pulsatile biventricular circulatory mock loop.MethodsTwo UVAD pumps were tested in a dual setup (BVAD) in the circulatory model with the simulated conditions of left heart failure (HF), right HF, and moderate/severe biventricular HF (BHF). The total flow, aortic pulse pressure, the pulse augmentation factor (PAF), the energy-equivalent pressure (EEP), and the surplus hemodynamic energy (SHE) were observed at various pump speeds to evaluate the pulsatility.ResultsThe aortic pulse pressure increased from the baseline (without pump) in all simulated hemodynamic conditions. The PAF ranged from 17%-35% in healthy, left HF, right HF, and mild BHF conditions, with the highest PAF of 90% being observed in the severe BHF condition. The EEP correlated with LVAD flow in all groups (R2 = 0.87-0.97) and increased from the baseline in all cases. The SHE peaked at approximately 5-6 L/min of LVAD support and was likely to decrease at higher LVAD pump flow. The largest decrease in SHE from the baseline, 53%, was observed in the mild BHF conditions with the highest LVAD and RVAD support.ConclusionsThe UVAD successfully demonstrated the ability to preserve pulsatility in vitro, and to optimize the cardiac output, as an isolated circulatory support device option (RVAD or LVAD) and when used for BVAD support. Biventricular support with UVAD amplified the aortic pulse pressure. The biventricular UVAD also preserved the EEP and the SHE.image