Flow Behavior Within the 12‐cc Penn State Pulsatile Pediatric Ventricular Assist Device: An Experimental Study of the Initial Design

Manning, Keefe B.; Wivholm, Brandon D; Yang, Ning; Fontaine, Arnold A.; Deutsch, Steven

doi:10.1111/j.1525-1594.2008.00565.x

Cited by 19 publications

(24 citation statements)

References 17 publications

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“…In Manning et al ,74 planar PIV was used to explore the flow behavior of the Penn State 12 cc pneumatic pediatric assist pump with Bjork–Shiley Monostrut 17 mm MHV, operated at 86 bpm using 40% hematocrit viscoelastic analog fluid. Wall shear maps complemented the velocity data collected.…”

Section: The Penn State Artificial Heartmentioning

confidence: 99%

Towards Non-thrombogenic Performance of Blood Recirculating Devices

2010

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Implantable blood recirculating devices have provided life saving solutions to patients with severe cardiovascular diseases. However, common problems of hemolysis and thromboembolism remain an impediment to these devices. In this article, we present a brief review of the work by several groups in the field that has led to the development of new methodologies that may facilitate achieving the daunting goal of optimizing the thrombogenic performance of blood recirculating devices. The aim is to describe work which pertains to the interaction between flow-induced stresses and the blood constituents, and that supports the hypothesis that thromboembolism in prosthetic blood recirculating devices is initiated and maintained primarily by the non-physiological flow patterns and stresses that activate and enhance the aggregation of blood platelets, increasing the risk of thromboembolism and cardioembolic stroke. Such work includes state-of-the-art numerical and experimental tools used to elucidate flow-induced mechanisms leading to thromboembolism in prosthetic devices. Following the review, the paper describes several efforts conducted by some of the groups active in the field, and points to several directions that should be pursued in the future in order to achieve the goal for blood recirculating prosthetic devices becoming more effective as destination therapy in the future.

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Section: The Penn State Artificial Heartmentioning

confidence: 99%

Towards Non-thrombogenic Performance of Blood Recirculating Devices

2010

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“…Each of these studies assessed the flow field of the PVAD including wall shear rate estimates resulting in specific design changes and device operation. The flow in the PVAD is more complex than that in similar adult devices, including increases in sensitivity to small changes such as valve orientation and filling time [7][8][9][10][11].…”

Section: Resultsmentioning

confidence: 98%

Thrombus prediction in adult and pediatric pulsatile ventricular assist devices: The role of experimental fluid dynamics

Nanna

Roszelle

Cooper

et al. 2010

Proceedings of the 2010 IEEE 36th Annual Northeast Bioengineering Conference (NEBEC)

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Ventricular assist devices (VADs) are actively used for congestive heart failure and myocarditis patients but clinical issues, such as thrombosis, still remain as work continues toward development as destination therapy devices. As Penn State continues to develop smaller generation VADs, the role of experimental fluid dynamics has increased as the capability to predict thrombus deposition using wall shear estimates has improved based on animal studies. These experimental data are leading towards the development of computational simulations to identify areas not easily visualized experimentally. Particle image velocimetry, an optical measurement technique, has been adapted and the resulting velocity data, post-processed, to extract wall shear rates throughout different areas of adult (50cc) and pediatric (12cc) VADs. The results indicate areas susceptible to thrombosis and where subsequent VAD design changes have improved the flow with adequate wall shear. The role of experimental fluid dynamic measurements have greatly improved our ability to predict areas of thrombus deposition leading to improved VAD designs, provide a foundation for computer simulations with correlations to in vivo animal testing.

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“…These include flow characterization, valve selection, valve orientation, device three-dimensionality, and most recently the effect of varying clinical conditions on the flow field. 7,8,15,[18][19][20] Overall, we have found that the PVAD has a flow field with adequate wall washing under normal operating conditions. The reduced volume of the PVAD makes the flow in the body of the pump more sensitive, so that changes in the valve position and inflow and outflow cannulae affect the device flow field.…”

Section: Introductionmentioning

confidence: 90%

“…The outflow is of interest because we found an area of blockage upstream of the device's outlet valve, which had not been observed in adult devices using the same type of valve (Bjo¨rk-Shiley monostrut tilting disc valve, BSM). 12 The blockage, first observed by Manning et al, 15 occurs during late systole around the strut of the BSM valve. In the flow map given in Fig.…”

Section: Introductionmentioning

confidence: 97%

“…1 the blockage created a stagnation region that covered roughly 50% of the outlet port during late systole. 15 Velocities in the outlet jet are commonly seen above 1 m/s, while the area of blockage contains maximum velocities around 0.2 m/s. Because of this velocity difference, the blockage could lead to a greater than normal pressure drop around the valve, which could increase blood damage and blood residence time and lead to thrombus formation in the stagnant region.…”

Section: Introductionmentioning

confidence: 99%

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Flow Visualization of the Penn State Pulsatile Pediatric Ventricular Assist Device Cannulae and Change in Outlet Valve Placement

Roszelle

Fickes

Deutsch

et al. 2011

Cardiovasc Eng Tech

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Due to the lack of long-term mechanical circulatory support options for children, Penn State is developing a pneumatically driven 12 cc pulsatile pediatric ventricular assist device (PVAD). The reduction in volume, however, necessary to accommodate pediatric patients leads to changes in the functional fluid mechanics. One area that has not been previously observed is the flow upstream and downstream of the inlet and outlet valves. In particular an area of blockage, that includes a large area of stagnant flow, has been observed upstream of the outlet valve that could cause an increase in blood damage. In order to measure the flow upstream and downstream of the ports, we deploy a 50 mm acrylic valve extension. The outlet valve is moved downstream of the outlet port in an attempt to eliminate a flow blockage region upstream of the valve. We mount the PVAD to a mock circulatory loop that models the systemic circulation under normal physiological conditions, with a 40% hematocrit blood analog as the fluid. Two dimensional particle image velocimetry is used to measure the flow. As expected, the flow patterns in the body of the device remain similar to those without the extension, except near the outlet port. Nonuniform flow is observed upstream of both the inlet and outlet valves and regurgitation is observed upstream of the inlet valve. The relocation of the outlet valve leads to a more uniform outflow and the blockage region is eliminated. The observations of non-uniform flow upstream of the inlet valve are a new and important observation when considering computational models. Also, the new outlet flow pattern associated with the relocation of the outlet valve reduces the potential for blood damage. Studies with a relocated valve in a clinical model are being considered.

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Flow Behavior Within the 12‐cc Penn State Pulsatile Pediatric Ventricular Assist Device: An Experimental Study of the Initial Design

Cited by 19 publications

References 17 publications

Towards Non-thrombogenic Performance of Blood Recirculating Devices

Towards Non-thrombogenic Performance of Blood Recirculating Devices

Thrombus prediction in adult and pediatric pulsatile ventricular assist devices: The role of experimental fluid dynamics

Flow Visualization of the Penn State Pulsatile Pediatric Ventricular Assist Device Cannulae and Change in Outlet Valve Placement

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