A Two-stage Rotary Blood Pump Design with Potentially Lower Blood Trauma: A Computational Study

Thamsen, Bente; Mevert, Ricardo; Lommel, Michael; Preikschat, Philip; Gaebler, Julia; Krabatsch, Thomas; Kertzscher, Ulrich; Hennig, Ewald M.; Affeld, K.

doi:10.5301/ijao.5000482

Cited by 29 publications

(43 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is two orders of magnitude lower than CF devices such as the Thoratec HeartMate II ® (HMII) and HeartWare HVAD ® that have maximum wall shear stresses above 2000 Pa at the same flow and pressure conditions (21). …”

Section: Design Resultsmentioning

confidence: 96%

“…Thamsen et al used computational fluid dynamic simulations to model the flow in the HMII and HVAD pumps to understand the blood damage potential of CF devices (21, 22). They calculated the volume of blood above approximate thresholds for vWF unfolding (9 Pa), platelet activation (50 Pa), and hemolysis (150 Pa) as a way of quantifying the damage potential of a device.…”

Section: Design Resultsmentioning

confidence: 99%

“…The TORVAD has maximum wall shear stress two orders of magnitude less than continuous flow devices and only a small volume fraction of blood is exposed to shear above 9 Pa. No volume of blood in the TORVAD is exposed to shear above 50 Pa. Values for continuous flow devices were estimated using computational fluid dynamics as described by Thamsen et al (21, 22). …”

Section: Figurementioning

confidence: 99%

See 2 more Smart Citations

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

View full text Add to dashboard Cite

This article provides an overview of the design challenges associated with scaling the low-shear pulsatile TORVAD ventricular assist device (VAD) for treating pediatric heart failure. A cardiovascular system model was used to determine that a 15 ml stroke volume device with a maximum flow rate of 4 L/min can provide full support to pediatric patients with body surface areas between 0.6 to 1.5 m2. Low shear stress in the blood is preserved as the device is scaled down and remains at least two orders of magnitude less than continuous flow VADs. A new magnetic linkage coupling the rotor and piston has been optimized using a finite element model (FEM) resulting in increased heat transfer to the blood while reducing the overall size of TORVAD. Motor FEM has also been used to reduce motor size and improve motor efficiency and heat transfer. FEM analysis predicts no more than 1°C temperature rise on any blood or tissue contacting surface of the device. The iterative computational approach established provides a methodology for developing a TORVAD platform technology with various device sizes for supporting the circulation of infants to adults.

show abstract

Section: Design Resultsmentioning

confidence: 96%

Section: Design Resultsmentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

See 1 more Smart Citation

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Current generation continuous‐flow LVADs generate vascular wall shear stresses up to two orders of magnitude greater than normal physiologic values 6 . Consequently, in LVAD patients, supraphysiologic shear stress significantly increases the degradation of VWF by ADAMTS‐13.…”

Section: Discussionmentioning

confidence: 99%

“…The HeartMate II was not designed to minimize shear stress. The axial‐flow design that includes a hydrodynamic bearing and small flow gaps (50 µm) generates a peak shear stress greater than 1500 Pa, 6 whereas normal intravascular shear stress approximately 2 to 8 Pa 32 . Importantly, physiologic levels of shear stress cannot be achieved while operating the HeartMate II with an RPM in the clinical operational range 14 .…”

Section: Discussionmentioning

confidence: 99%

Decreased RPM reduces von Willebrand factor degradation with the EVAHEART LVAS: implications for device‐specific LVAD management

Bartoli

Kang

Motomura³

2020

J Card Surg

View full text Add to dashboard Cite

Background Continuous‐flow left ventricular assist devices (LVADs) produces supraphysiologic shear stress that causes von Willebrand factor (VWF) degradation and a bleeding diathesis. Reduction of revolutions per minute (RPM) with axial‐flow LVADs does not decrease shear stress enough to reduce VWF degradation and bleeding. However, it is unknown if RPM reduction with centrifugal flow LVADs may minimize VWF degradation. We tested the hypothesis that RPM reduction preserves VWF multimers in the centrifugal‐flow EVAHEART left ventricular assist system (LVAS), which is designed to minimize shear stress and blood trauma. Methods Whole blood samples were collected from humans (n = 28). Blood was circulated in ex vivo mock circulatory loops for 6 hours with an EVAHEART LVAS at 2300 (n = 12), 2100 (n = 8), or 1800 RPM (n = 8). Immunoblotting was used to resolve and quantify VWF multimers and degradation fragments. Results RPM reduction from 2300 to 2100 to 1800 RPM significantly decreased EVAHEART blood flow from 5.8 ± 0.4 to 4.3 ± 0.6 to 4.1 ± 0.5 L/min (analysis of variance [ANOVA], P = .03). RPM reduction protected VWF from pathologic degradation. At lower RPMs, significantly greater levels of VWF multimers were observed (ANOVA, P = .001). Similarly, at lower RPMs, significantly fewer VWF fragments, a product of VWF degradation, were observed (ANOVA, P = .007). Conclusions RPM reduction significantly reduced VWF degradation with the centrifugal‐flow EVAHEART LVAS, an LVAD specifically designed with low shear stress. Different LVADs have unique hematologic footprints and should be managed with device‐specific protocols. Adjustment of RPM to minimize blood trauma while still maintaining physiologic hemodynamics has the potential to decrease complications related to LVAD‐associated von Willebrand's disease, such as gastrointestinal bleeding and hemorrhagic stroke.

show abstract

LVAD‐Associated Acquired von Willebrand Syndrome and Gastrointestinal Bleeding: Pathophysiology, Etiologies, and Management

Ramdeen,

Bartoli

2023

Textbook of Transplantation and Mechanical Support for End‐Stage Heart and Lung Disease

View full text Add to dashboard Cite

A Two-stage Rotary Blood Pump Design with Potentially Lower Blood Trauma: A Computational Study

Abstract: Hence, blood trauma might be reduced with this design. Based on these encouraging results, future in vitro investigations to investigate actual blood damage are intended.

Cited by 29 publications

References 23 publications

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

Decreased RPM reduces von Willebrand factor degradation with the EVAHEART LVAS: implications for device‐specific LVAD management

LVAD‐Associated Acquired von Willebrand Syndrome and Gastrointestinal Bleeding: Pathophysiology, Etiologies, and Management

Contact Info

Product

Resources

About