An Implantable Centrifugal Blood Pump for Long Term Circulatory Support

Yamazaki, Kenji; Litwak, Philip; Kormos, Robert L.; Mōri, Toshio; Tagusari, Osamu; Antaki, James F.; Kameneva, Marina V.; Watach, Mary J.; Gordon, Lisa; Umezu, Mitsuo; Tomioka, Jun; Koyanagi, Hitoshi; Griffith, Bartley P.

doi:10.1097/00002480-199709000-00072

Cited by 32 publications

(14 citation statements)

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“…16) The EVAHEART® cannulas are thick enough to lower circuit resistance. 4) As a limitation of this paper, there is a possibility of heart rate elevation raising pump flow. Akimoto et al noted this possibility.…”

Section: Fig 1 Pump Flow During Exercise Visualized With Ultrasoundmentioning

confidence: 94%

“…It was placed in the left subcostal space, and left-ventricle-aorta bypass was established. 4,5) The pump speed was from 1900 rpm to 2100 rpm, and anticoagulation with oral Coumadin was administered to maintain international normalized ratio (INR) 2.0 to 3.0 times normal.…”

Section: Methodsmentioning

confidence: 99%

“…EVAHEART® is an implantable centrifugal blood pump, with a pump size of 55 × 64 mm, and made from pure titanium, and weighing 420g. 4,5) In Japan, EVAHEART® has been covered by National Health Insurance since March 2011, and a clinical trial of EVAHEART® in the United States has been started.…”

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confidence: 99%

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Spontaneous Increase in EVAHEART® Pump Flow at a Constant Pump Speed during Exercise Examination

Kurihara

Nishimura

Imanaka

et al. 2012

ATCS

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Purpose: Ventricular assist devices have been used for the treatment of severe heart failure. Recently, many types of blood pumps have been developed to reduce major adverse events. EVAHEART® (Sun Medical Technology Research Corporation, Nagano, Japan) is an implantable centrifugal blood pump. In laboratory animal studies, the pump flow of EVA-HEART® increases spontaneously during exercise with no changes in pump control parameters. However, this has not been confirmed clinically. The aim of this study was to analyze EVAHEART® performance during exercise. Patients and methods: Four male patients were implanted with an EVAHEART®. We evaluated the performance of the EVAHEART® during exercise. Fixed pump speeds were maintained during each test. Measurements during exercise were peak load, peak oxygen consumption (peak VO 2 ), pre exercise pump flow, and peak velocity. Results: Pump flow significantly increased from 4.1 ± 0.5 liters per minute (L/min) to 7.2 ± 1.8 L/min during exercise. VO 2 increased from 4.0 ± 0.7 milliliters per kilogram per minute (ml/kg/min) to 14.7 ± 3.3 ml/kg/min. Conclusion: These results indicate that EVAHEART® may support severe heart failure patients not only under static but also under dynamic conditions. Pump flow spontaneously increased during exercise at a constant pump speed.

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Section: Fig 1 Pump Flow During Exercise Visualized With Ultrasoundmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

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Spontaneous Increase in EVAHEART® Pump Flow at a Constant Pump Speed during Exercise Examination

Kurihara

Nishimura

Imanaka

et al. 2012

ATCS

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“…Continuous-flow LVAD with a pulsatile driving technique had not been tried or discussed before our group's report, however. Previously, we developed and introduced a power-control unit for a centrifugal LVAD (EVAHEARTÒ; Sun Medical Technology Research Corporation, Nagano, Japan) [5,6]. With this unit we define the distance and rotational speed (RS) of the systolic and diastolic phases to drive the EVAHEARTÒ so it is synchronized with the native heart rate.…”

Section: Introductionmentioning

confidence: 99%

Alteration of LV end-diastolic volume by controlling the power of the continuous-flow LVAD, so it is synchronized with cardiac beat: development of a native heart load control system (NHLCS)

et al. 2011

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There are many reports comparing pulsatile and continuous-flow left ventricular assist devices (LVAD). But continuous-flow LVAD with the pulsatile driving technique had not been tried or discussed before our group's report. We have previously developed and introduced a power-control unit for a centrifugal LVAD (EVAHEART®; Sun Medical), which can change the speed of rotation so it is synchronized with the heart beat. By use of this unit we analyzed the end-diastolic volume (EDV) to determine whether it is possible to change the native heart load. We studied 5 goats with normal hearts and 5 goats with acute LV dysfunction because of micro-embolization of the coronary artery. We used 4 modes, "circuit-clamp", "continuous", "counter-pulse", and "co-pulse", with the bypass rate (BR) 100%. We raised the speed of rotation of the LVAD in the diastolic phase with the counter-pulse mode, and raised it in the systolic phase with the co-pulse mode. As a result, the EDV decreased in the counter-pulse mode and increased in the co-pulse mode, compared with the continuous mode (p < 0.05), in both the normal and acute-heart-failure models. This result means it may be possible to achieve favorable EDV and native heart load by controlling the rotation of continuous-flow LVAD, so it is synchronized with the cardiac beat. This novel driving system may be of great benefit to patients with end-stage heart failure, especially those with ischemic etiology.

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“…4 Denaturation of blood proteins can occur at surface temperatures above 40°C. 5 During a severe fever, the patient's thermoregulatory set point is elevated and the temperature of blood passing through the pump, T ϱ , can be higher than 40°C, further increasing the risk of cell damage. As a safeguard, our group set the target maximum blood and tissue contacting surface temperature as 2°C (or less) above body temperature during the system design and optimization process.…”

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confidence: 99%

Thermal Analysis of the PediaFlow Pediatric Ventricular Assist Device

Gardiner

Wu²,

Noh³

et al. 2007

ASAIO Journal

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Accurate modeling of heat dissipation in pediatric intracorporeal devices is crucial in avoiding tissue and blood thermotrauma. Thermal models of new Maglev ventricular assist device (VAD) concepts for the PediaFlow VAD are developed by incorporating empirical heat transfer equations with thermal finite element analysis (FEA). The models assume three main sources of waste heat generation: copper motor windings, active magnetic thrust bearing windings, and eddy currents generated within the titanium housing due to the two-pole motor. Waste heat leaves the pump by convection into blood passing through the pump and conduction through surrounding tissue. Coefficients of convection are calculated and assigned locally along fluid path surfaces of the three-dimensional pump housing model. FEA thermal analysis yields a three-dimensional temperature distribution for each of the three candidate pump models. Thermal impedances from the motor and thrust bearing windings to tissue and blood contacting surfaces are estimated based on maximum temperature rise at respective surfaces. A new updated model for the chosen pump topology is created incorporating computational fluid dynamics with empirical fluid and heat transfer equations. This model represents the final geometry of the first generation prototype, incorporates eddy current heating, and has 60 discrete convection regions. Thermal analysis is performed at nominal and maximum flow rates, and temperature distributions are plotted. Results suggest that the pump will not exceed a temperature rise of 2 degrees C during normal operation.

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An Implantable Centrifugal Blood Pump for Long Term Circulatory Support

Cited by 32 publications

References 0 publications

Spontaneous Increase in EVAHEART® Pump Flow at a Constant Pump Speed during Exercise Examination

Spontaneous Increase in EVAHEART® Pump Flow at a Constant Pump Speed during Exercise Examination

Alteration of LV end-diastolic volume by controlling the power of the continuous-flow LVAD, so it is synchronized with cardiac beat: development of a native heart load control system (NHLCS)

Thermal Analysis of the PediaFlow Pediatric Ventricular Assist Device

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