Rotational speed modulation used with continuous-flow left ventricular assist device provides good pulsatility†

Naito, Noritsugu; Nishimura, Takashi; Iizuka, Kotaro; Takewa, Yoshiaki; Umeki, Akihide; Ando, Masahiko; Ōno, Minoru; Tatsumi, Eisuke

doi:10.1093/icvts/ivx236

Cited by 22 publications

(14 citation statements)

References 20 publications

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“…The impeller speed of the constant speed pattern was the reference speed of the sinusoidal speed pattern. The pulsatile speed pattern waveform was determined using the human aorta waveform, which consisted of the sinusoidal and constant parts, as shown in Equation (5). The reference speed ω 1 of the sinusoidal part was 2400 rpm, and the amplitude A 1 was 400 rpm.…”

Section: Speed Modulation Of the Blood Pump Impellermentioning

confidence: 99%

“…Although it has been widely used in clinically treating patients with heart failure and has achieved a good auxiliary effect, some complications still exist, such as bleeding, aortic valve insufficiency, and thrombosis, in patients with heart failure, seriously affecting the treatment effect and the quality of life [3]. Therefore, some studies have explored the possibility that the blood flow rate and pressure at the outlet of CFBP can be similar to the pulsatile-flow output by means of impeller speed modulation [4][5][6], and investigated the differences in the hemodynamic characteristics between a CFBP and a PFBP.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Impeller Speed Patterns on Hemodynamic Characteristics and Hemolysis of the Blood Pump

et al. 2019

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A continuous-flow output mode of a rotary blood pump reduces the fluctuation range of arterial blood pressure and easily causes complications. For a centrifugal rotary blood pump, sinusoidal and pulsatile speed patterns are designed using the impeller speed modulation. This study aimed to analyze the hemodynamic characteristics and hemolysis of different speed patterns of a blood pump in patients with heart failure using computational fluid dynamics (CFD) and the lumped parameter model (LPM). The results showed that the impeller with three speed patterns (including the constant speed pattern) met the normal blood demand of the human body. The pulsating flow generated by the impeller speed modulation effectively increased the maximum pulse pressure (PP) to 12.7 mm Hg, but the hemolysis index (HI) in the sinusoidal and pulsatile speed patterns was higher than that in the constant speed pattern, which was about 2.1 × 10−5. The flow path of the pulsating flow field in the spiral groove of the hydrodynamic suspension bearing was uniform, but the alternating high shear stress (0~157 Pa) was caused by the impeller speed modulation, causing blood damage. Therefore, the rational modulation of the impeller speed and the structural optimization of a blood pump are important for improving hydrodynamic characteristics and hemolysis.

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Section: Speed Modulation Of the Blood Pump Impellermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Impeller Speed Patterns on Hemodynamic Characteristics and Hemolysis of the Blood Pump

et al. 2019

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“…The undulating membrane reproducing blood movement, 11 toroidal flow pump, 12 helical flow device, 13 rotary piston blood pump, 14 shrouded impeller design, 15 and cannulation techniques 16 are all attempting to demonstrate new possibilities and potential benefits over the "classic" centrifugal pumps and existing solutions. Future controller solutions are seeking to enable remote hospital monitoring, more intuitive system interface, optimized control solutions, 17 pump speed modulation, 18 and the potential to use a single controller to automatically control a biventricular assist device configuration. 10 It is important to understand, however, that the uniqueness of any new MCS system will lie in its ability to provide comparable or superior performance with less thrombogenicity in a smaller size (which may allow for use in pediatric patients within device design points) and will preferably be suitable for less-invasive implantation techniques.…”

Section: Progress In Mechanical Circulatory Support: Challenges and Omentioning

confidence: 99%

Human Fitting Studies of Cleveland Clinic Continuous-Flow Total Artificial Heart

et al. 2015

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Implantation of mechanical circulatory support devices is challenging, especially in patients with a small chest cavity. We evaluated how well the Cleveland Clinic continuous-flow total artificial heart (CFTAH) fit the anatomy of patients about to receive a heart transplant. A mock pump model of the CFTAH was rapid-prototyped using biocompatible materials. The model was brought to the operative table, and the direction, length, and angulation of the inflow/outflow ports and outflow conduits were evaluated after the recipient's ventricles had been resected. Thoracic cavity measurements were based on preoperative computed tomographic data. The CFTAH fit well in all five patients (height, 170 ± 9 cm; weight, 75 ± 24 kg). Body surface area was 1.9 ± 0.3 m2 (range, 1.6-2.1 m2). The required inflow and outflow port orientation of both the left and right housings appeared consistent with the current version of the CFTAH implanted in calves. The left outflow conduit remained straight, but the right outflow direction necessitated a 73 ± 22 degree angulation to prevent potential kinking when crossing over the connected left outflow. These data support the fact that our design achieves the proper anatomical relationship of the CFTAH to a patient's native vessels.

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“…This control method alters rotational speed (RS) of the RBP within a cardiac cycle; for instance, the RS is increased in systole and decreased in diastole, and vice versa. Both experimental and theoretical studies demonstrated that the CBS control can boost pulsatility and reduce load on the LV 12‐15 . Both pulsatility and left ventricular energetics are important indices in management of LVAD patients 16‐18 .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of cardiac beat synchronization control for a rotary blood pump on valvular regurgitation with a mathematical model

Ogawa¹,

Kobayashi²,

Yamazaki

et al. 2020

Artificial Organs

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We have studied the cardiac beat synchronization (CBS) control for a rotary blood pump (RBP) and revealed that it can promote pulsatility and reduce cardiac load. Besides, patients with LVAD support sometimes suffer from aortic and mitral regurgitation (AR and MR). A control method for the RBP should be validated in wider range of conditions to clarify its benefits and pitfalls prior to clinical application. In this study, we evaluated pulsatility and cardiac load reduction obtained with the CBS control on valvular failure conditions with a mathematical model. Diastolic assist could reduce cardiac load on the left ventricle by decreasing external work of the ventricle even in MR cases while it was not so effective in AR cases. Systolic assist can still promote pulsatility in AR and MR cases; however, aortic valve function should be carefully confirmed since pulse pressure can be wider not due to systolic assist but to AR.

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Rotational speed modulation used with continuous-flow left ventricular assist device provides good pulsatility†

Abstract: The co-pulse mode of this novel RS modulation system may provide better pulsatility not only in the large vessels but also in the peripheral vasculature.

Cited by 22 publications

References 20 publications

Influence of Impeller Speed Patterns on Hemodynamic Characteristics and Hemolysis of the Blood Pump

Influence of Impeller Speed Patterns on Hemodynamic Characteristics and Hemolysis of the Blood Pump

Human Fitting Studies of Cleveland Clinic Continuous-Flow Total Artificial Heart

Evaluation of cardiac beat synchronization control for a rotary blood pump on valvular regurgitation with a mathematical model

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