Hemolytic Footprint of Rotodynamic Blood Pumps

Escher, Andreas; Gobel, Henrike; Nicolai, Marcel; Schlöglhofer, Thomas; Hubmann, Emanuel J.; Laufer, Günther; Meßner, Barbara; Kertzscher, Ulrich; Zimpfer, Daniel; Granegger, Marcus

doi:10.1109/tbme.2022.3146135

Cited by 12 publications

(14 citation statements)

References 37 publications

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“…The numerical hemolysis predictions were validated by previously reported hemolysis experiments of the two RBPs at the respective operating conditions (Table 1). [ 16 ] To verify how hydraulic energy dissipation (Equation (3)) relates to the respective NIH magnitude recorded in vitro, the corresponding scaling factors (Equation (8)) were determined by minimizing the error between energy dissipation ( e diss ) and in vitro hemolysis ( NIH Exp ) according to Equation (7).

\begin{equation}\mathop {\min }\limits_{{\varphi _{\rm{i}}}} f\left( {{\varphi _{\rm{i}}}} \right)\;{\rm{with}}\;f\;\left( {{\varphi _{\rm{i}}}} \right) = \sqrt {\frac{1}{N}\left( {\mathop \sum \limits_{{\rm{k}} = 1}^{\rm{N}} {{\left( {NI{H_{{\rm{Exp}}}} - {\varphi _{\rm{i}}} \cdot {e_{{\rm{diss}}}}} \right)}^2}} \right)} \end{equation}

\begin{equation}{\hat e_{{\rm{diss}}}} = {\varphi _{\rm{i}}}\; \cdot {e_{{\rm{diss}}}}\end{equation}

where φ i [(mL g) (J 100L) –1 ] is the scaling factor, i [–] is the index of pump system representing either the HM3 or the HVAD, N (= 9) [–] the number of operating conditions,

NI{H_{{\rm{Exp}}}}

[g (100L) –1 ] the experimentally determined normalized index of hemolysis, e diss [J mL –1 ] the hydraulic energy dissipation, and

{\hat e_{{\rm{diss}}}}

the scaled hydraulic energy dissipation [g (100L) –1 ].…”

Section: Methodsmentioning

confidence: 99%

“…The numerical hemolysis predictions were validated by previously reported hemolysis experiments of the two RBPs at the respective operating conditions (Table 1). [16] To verify how hydraulic energy dissipation (Equation ( 3)) relates to the respective NIH magnitude recorded in vitro, the corresponding scaling factors (Equation ( 8)) were determined by minimizing the error between energy dissipation (e diss ) and in vitro hemolysis (NIH Exp ) according to Equation (7).…”

Section: Hemolysismentioning

confidence: 99%

“…For flow analysis based on computational fluid dynamics (CFD), the pump geometries of both RBPs were reverse engineered as previously described. [14,15] Corresponding priming volumes were spatially discretized to high-quality computational grids (HM3: ≈9.9 million cells; HVAD: ≈8 million cells) as presented in Escher et al, [16] and grid quality was verified a posteriori (see Supporting Information). Both grid generation and in silico flow analysis were performed in the commercial software StarCCM+ (Siemens, Munich, Germany).…”

Section: Spatial Discretization Of Pump Volumementioning

confidence: 99%

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Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

Escher

Hubmann

Karner

et al. 2022

Advcd Theory and Sims

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In rotodynamic blood pumps (RBPs) a substantial proportion of input energy is dissipated into the blood. This energy may propel damaging work on blood constituents. To date, the link between this hydraulic energy dissipation and respective hemolytic action in RBPs remains vastly unknown. In this study, computational fluid dynamics is applied to compute the hydraulic energy dissipation at 9 operating conditions in two RBPs (HM3: HeartMate 3; HVAD: HeartWare Ventricular Assist Device). Respective interrelations with hemolytic pump performance are elucidated by comparing these computations with in silico predicted and in vitro measured hemolysis. Despite different pump geometries, hydraulic loss magnitudes, and distributions, global hydraulic energy dissipation shows strong correlation (r > 0.95) to in vitro hemolysis with scaling factors in the same order of magnitude for both devices (𝝋 HM3 = 0.599 (mL g) (J 100L) -1 ; 𝝋 HVAD = 0.716 (mL g) (J 100L) -1 ). The analytical description of hydraulic energy dissipation reveals to be a function of shear stresses and exposure time, unmasking its analogy to the power-law formulation of hemolysis. This hydraulics-based analysis may denote a step ahead to relate turbomachinery to bioengineering and may provide mechanistic insights into the relation between RBP design, hydraulic properties, and hemolytic performance.

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\begin{equation}\mathop {\min }\limits_{{\varphi _{\rm{i}}}} f\left( {{\varphi _{\rm{i}}}} \right)\;{\rm{with}}\;f\;\left( {{\varphi _{\rm{i}}}} \right) = \sqrt {\frac{1}{N}\left( {\mathop \sum \limits_{{\rm{k}} = 1}^{\rm{N}} {{\left( {NI{H_{{\rm{Exp}}}} - {\varphi _{\rm{i}}} \cdot {e_{{\rm{diss}}}}} \right)}^2}} \right)} \end{equation}

\begin{equation}{\hat e_{{\rm{diss}}}} = {\varphi _{\rm{i}}}\; \cdot {e_{{\rm{diss}}}}\end{equation}

where φ i [(mL g) (J 100L) –1 ] is the scaling factor, i [–] is the index of pump system representing either the HM3 or the HVAD, N (= 9) [–] the number of operating conditions,

NI{H_{{\rm{Exp}}}}

[g (100L) –1 ] the experimentally determined normalized index of hemolysis, e diss [J mL –1 ] the hydraulic energy dissipation, and

{\hat e_{{\rm{diss}}}}

the scaled hydraulic energy dissipation [g (100L) –1 ].…”

Section: Methodsmentioning

confidence: 99%

“…The numerical hemolysis predictions were validated by previously reported hemolysis experiments of the two RBPs at the respective operating conditions (Table 1). [16] To verify how hydraulic energy dissipation (Equation ( 3)) relates to the respective NIH magnitude recorded in vitro, the corresponding scaling factors (Equation ( 8)) were determined by minimizing the error between energy dissipation (e diss ) and in vitro hemolysis (NIH Exp ) according to Equation (7).…”

Section: Hemolysismentioning

confidence: 99%

Section: Spatial Discretization Of Pump Volumementioning

confidence: 99%

See 1 more Smart Citation

Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

Escher

Hubmann

Karner

et al. 2022

Advcd Theory and Sims

Self Cite

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show abstract

“…By using the results of the experimental hydraulic study and FEM simulations as boundary conditions for CFD simulations, hemocompatibility related parameters of the ShuttlePump were evaluated, revealing promising results regarding blood damage, washout, and thermal behavior. The numerical hemolysis prediction shows a 15% lower NIH value than for a state-of-the-art LVAD HeartMate 3 (Abbott inc.) at a similar operating condition [28], an advantage attributable to the lower velocities and shear stresses within the ShuttlePump. Of note, the peak shear stress observed near the in-and outlets of the pump was the result of high-velocity gradients.…”

Section: Discussionmentioning

confidence: 99%

A Novel Pumping Principle for a Total Artificial Heart

Bierewirtz¹,

Narayanaswamy²,

Giuffrida³

et al. 2023

Preprint

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Objective: Total artificial hearts (TAH) are used as a temporary treatment for severe biventricular heart failure. Long-term cardiac replacement is hampered by limited durability and complication rates, which may be attributable to the modus operandi of state-of-the-art pumping systems. The aim of this study was to assess the feasibility of a novel valveless pumping principle for a durable pulsatile TAH (ShuttlePump). Methods: With a rotating and linearly shuttling piston within a cylindrical housing with 2 in- and outlets, the pump features only one single moving part and delivers pulsatile flow to both systemic and pulmonary circulation. The pump and actuation system were designed iteratively based on analytical and in silico methods, utilizing finite element methods (FEM) and computational fluid dynamics (CFD) Pump characteristics were evaluated experimentally in a mock circulation loop mimicking the cardiovascular system, while hemocompatibility related parameters were calculated numerically. Results: Pump characteristics cover the entire required operating range for a TAH (2.5 - 9L/min at 50 - 160mmHg arterial pressures) at stroke frequencies of 1.5 - 5Hz while balancing left and right atrial pressures. FEM analysis showed a mean overall copper losses of 8.84W, resulting in local blood temperature rise of < 2k. The CFD results of normalized index of hemolysis was 3.57 mg/100L and 95% of the pumps blood volume was exchanged after 1.42s. Conclusion: This study indicates feasibility of a novel pumping system for a TAH with numerical and experimental results substantiating further development of the ShuttlePump.

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“…With the aim to link device-related hemocompatibility to the respective hydraulic pump characteristics, we recently identified a correlation between hemolytic action and the hydraulic energy which is globally dissipated into the blood in state-of-the-art RBPs. 3,4 To unravel the highly localized, hemolytic effects in RBPs this global analysis requires expansion toward local considerations of energy dissipation.…”

mentioning

confidence: 99%

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

et al. 2023

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Computational fluid dynamics (CFD) is a powerful tool for the in-silico evaluation of rotodynamic blood pumps (RBPs). Corresponding validation, however, is typically restricted to easily accessible, global flow quantities. This study showcased the HeartMate 3 (HM3) to identify feasibility and challenges of enhanced in-vitro validation in third-generation RBPs. To enable high-precision acquisition of impeller torques and grant access for optical flow measurements, the HM3 testbench geometry was geometrically modified. These modifications were reproduced in silico, and global flow computations validated along 15 operating conditions. The globally validated flow in the testbench geometry was compared with CFD-simulated flows in the original geometry to assess the impact of the necessary modifications on global and local hydraulic properties. Global hydraulic properties in the testbench geometry were successfully validated (pressure head: r = 0.999, root mean square error [RMSE] = 2.92 mmHg; torque: r = 0.996, RMSE = 0.134 mNm). In-silico comparison with the original geometry demonstrated good agreement (r > 0.999, relative errors < 11.97%) of global hydraulic properties. Local hydraulic properties (errors up to 81.78%) and hemocopatibility predictions (deviations up to 21.03%), however, were substantially affected by the geometric modifications. Transferability of local flow measures derived on advanced in-vitro testbenches toward original pump designs is challenged by significant local effects associated with the necessary geometrical modifications.

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Hemolytic Footprint of Rotodynamic Blood Pumps

Cited by 12 publications

References 37 publications

Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

Linking Hydraulic Properties to Hemolytic Performance of Rotodynamic Blood Pumps

A Novel Pumping Principle for a Total Artificial Heart

In-Vitro Flow Validation of Third-Generation Ventricular Assist Devices: Feasibility and Challenges

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