Clinical evaluation method and equipment for hemodialysis catheter performance, medium and program product

Abstract

The invention specifically discloses a clinical evaluation method and equipment for the performance of a hemodialysis catheter, a medium and a program product. The method comprises the following steps: carrying out geometric modeling on the hemodialysis catheter and a superior vena cava; performing high-precision grid division and blood flow analog simulation on the geometric models of the hemodialysis catheter and the superior vena cava; boundary condition setting is conducted on all boundaries of a fluid domain in the geometric model, and eddy current analysis and flow weight construction are conducted; through particle tracking in the hemodialysis catheter, integration is carried out on the backflow particle proportion in a volume integration mode in the blood flow area around the whole catheter, and recirculation rate calculation is carried out. According to the method, the estimation accuracy of the recirculation rate of the hemodialysis catheter can be improved, and theoretical guidance for performance optimization of the hemodialysis catheter is met.

Description

Technical Field

[0001] This invention relates to the technical field of clinical evaluation of hemodialysis catheters, and more specifically, to a method, device, medium, and procedure for clinical evaluation of the performance of hemodialysis catheters. Background Technology

[0002] In existing technologies, the clinical assessment of recirculation rate in hemodialysis catheters mainly relies on the detection of specific solute concentrations in the blood at the arterial and venous ends of the catheter. Representative methods include the blood urea nitrogen method, the glucose injection test, and the ultrasonic dilution method. However, the measurement accuracy of these concentration-based methods is easily affected by the "solute rebound" phenomenon, resulting in generally poor repeatability and accuracy of the measurement results, and there is a risk of systematically overestimating the recirculation rate. To overcome these limitations, some studies have turned to numerical simulation techniques based on computational fluid dynamics, or combined with methods such as in vitro particle imaging velocimetry. These techniques indirectly assess the recirculation rate by constructing and analyzing flow field models inside and around the catheter. Although they avoid the solute rebound problem to some extent, they mostly rely on macroscopic flow balance or static particle release counting. For example, the recirculation rate is defined by calculating the ratio of the number of particles captured in the arterial lumen to the total number released in the venous lumen, or by estimating it by measuring the dye concentration in the steady-state flow field. While these methods are intuitive, they generally neglect the crucial local transient vortex structures and their dynamic characteristics within the flow field. They fail to establish the intrinsic correlation between the tip jet, side-hole outflow, and local vortex intensity, resulting in insufficient understanding of the mechanisms of recirculation induced by complex flows and limited predictive accuracy. This leads to a lack of precise theoretical guidance for catheter performance optimization, making it difficult to meet the needs of precision medicine. Therefore, accurately assessing the clinical performance of hemodialysis catheters to meet the requirements of precision medicine is of great significance. Summary of the Invention

[0003] This invention provides a clinical assessment method, device, medium, and procedure for hemodialysis catheter performance, addressing the shortcomings of existing clinical assessments of hemodialysis catheter performance, which lack accuracy and fail to meet the needs of precision medicine. It improves the accuracy of hemodialysis catheter recirculation rate estimation and provides theoretical guidance for hemodialysis catheter performance optimization.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A clinical assessment method for the performance of hemodialysis catheters, comprising:

[0006] Geometric modeling of hemodialysis catheters and superior vena cava;

[0007] High-precision mesh generation and blood flow simulation were performed on the geometric models of hemodialysis catheters and superior vena cava.

[0008] Boundary conditions are set for each boundary of the fluid domain in the geometric model, and eddy current analysis and flow weight construction are performed.

[0009] By tracking particles within the hemodialysis catheter, the proportion of returning particles is integrated in a volume integral manner within the entire blood flow area surrounding the catheter, and the recirculation rate is calculated.

[0010] Preferably, the geometric modeling of the hemodialysis catheter and superior vena cava includes:

[0011] Using SolidWorks software and its parametric modeling function, a geometric model of the hemodialysis catheter and superior vena cava was constructed. The geometric model includes key features such as a dual-lumen design, side holes, distal end, and tip.

[0012] Preferably, the high-precision mesh generation and blood flow simulation of the geometric model of the hemodialysis catheter and superior vena cava includes:

[0013] The duct model is discretized with high precision using a polyhedral mesh, and local mesh refinement is implemented for key flow regions, including: the side hole surface, the inner wall of the lumen, and the tip region.

[0014] A boundary layer mesh is set at the fluid-solid interface to accurately simulate the velocity gradient and shear stress distribution in the near-wall region, ensuring the reliability of blood flow simulation.

[0015] Preferably, the high-precision mesh generation and blood flow simulation of the geometric model of the hemodialysis catheter and superior vena cava further includes:

[0016] The incompressible Navier-Stokes equations corresponding to the geometric models of the hemodialysis catheter and superior vena cava were numerically solved using a laminar flow model to obtain the blood flow velocity field distribution over a complete cycle.

[0017] Preferably, setting boundary conditions for each boundary of the fluid domain in the geometric model includes:

[0018] The superior vena cava inlet is set as a velocity inlet that follows a pulsatile waveform to simulate periodically changing blood flow input;

[0019] The corresponding outlet is set as a pressure outlet with a fixed reference value to characterize the downstream flow environment;

[0020] The properties of the blood material were set as an incompressible Newtonian fluid, with density and dynamic viscosity selected from typical values ​​of blood.

[0021] Preferably, the step of performing eddy current analysis and flow weight construction includes:

[0022] A dynamic weighting function based on eddy current and pulsation characteristics is introduced to enhance the hydrodynamic calculation of the recirculation rate of hemodialysis catheters. The enhanced hydrodynamic calculation includes: eddy current intensity calculation, superimposed eddy current intensity calculation, and flow rate weighting calculation.

[0023] The eddy current intensity calculation includes:

[0024] eddy current intensity V i The modulus defined as the curl of the velocity field According to the formula: Calculate the curl component, where, Here, u is the curl operator, and u is a three-dimensional velocity vector, where u x u y u z These represent the components of velocity in the x, y, and z directions of the rectangular coordinate system, respectively, where i, j, and k are unit vectors in the coordinate directions;

[0025] The calculation of the superimposed eddy current intensity includes:

[0026] Total eddy current intensity V i,total Equal to the eddy current intensity in the side hole region With the intensity of eddy currents in the tip region sum;

[0027] The traffic weight calculation includes:

[0028] According to the formula: Calculate the traffic weighting factor w, where Q max For maximum flow, Q min k1 and k2 are weighting coefficients for the minimum flow rate.

[0029] Preferably, the calculation of the recycling rate includes:

[0030] According to the formula: The recirculation rate RR is obtained by volume integral of the local recirculation probability density, where N returned To return the number of particles in the arterial lumen, N returned V represents the number of particles released, and V represents the volume of the blood flow region.

[0031] A computer device includes: a memory and a processor; the memory is used to store a computer program; the processor executes the computer program to implement the steps of the method described above.

[0032] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0033] A computer program product includes a computer program, characterized in that the computer program, when executed by a processor, implements the steps of the above-described method. This invention provides a clinical evaluation method, device, medium, and program product for hemodialysis catheter performance. It models and simulates the hemodialysis catheter and superior vena cava, integrates the proportion of reflux particles in a volumetric manner across the entire blood flow region surrounding the catheter, performs eddy current analysis and weighting, and calculates the recirculation rate. This addresses the problem of insufficient accuracy in existing clinical evaluations of hemodialysis catheter performance, which fails to meet the needs of precision medicine. It improves the accuracy of hemodialysis catheter recirculation rate estimation and provides theoretical guidance for hemodialysis catheter performance optimization. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0035] Figure 1 This is a schematic diagram of a clinical evaluation method for the performance of hemodialysis catheters provided by the present invention.

[0036] Figure 2 This is a flowchart illustrating the method for calculating the recirculation rate of hemodialysis catheters provided in an embodiment of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0038] To address the current shortcomings in the accuracy of clinical assessments of hemodialysis catheter performance, which fail to meet the needs of precision medicine, this invention provides a method, device, medium, and procedure for clinical assessment of hemodialysis catheter performance. This addresses the issues of insufficient accuracy in existing clinical assessments of hemodialysis catheter performance, improving the accuracy of hemodialysis catheter recirculation rate estimation and providing theoretical guidance for optimizing hemodialysis catheter performance.

[0039] like Figure 1 and Figure 2 As shown, a clinical assessment method for the performance of hemodialysis catheters includes:

[0040] S1: Perform geometric modeling of the hemodialysis catheter and superior vena cava.

[0041] S2: Perform high-precision mesh generation and blood flow simulation on the geometric model of the hemodialysis catheter and superior vena cava.

[0042] S3: Set boundary conditions for each boundary of the fluid domain in the geometric model, and perform eddy current analysis and flow weight construction.

[0043] S4: By tracking particles within the hemodialysis catheter, the proportion of returning particles is integrated in a volume integral manner within the entire blood flow area surrounding the catheter, and the recirculation rate is calculated.

[0044] In one embodiment, such as Figure 2 As shown, the modeling and simulation steps are as follows:

[0045] Step 1: Geometric Modeling and Mesh Generation. Using parametric modeling in SolidWorks, the geometric models of the HD catheter and SVC were constructed, providing a foundation for subsequent numerical simulations. The model structure mainly includes a dual-lumen design and key features such as side orifices and distal tips. The model was discretized with high precision using ANSYS Fluent Meshing. Local mesh refinement was implemented for key flow regions such as the side orifice surface, the inner wall of the lumen, and the tip. Simultaneously, boundary layer meshes with appropriate numbers and thicknesses were set at the fluid-solid interface to accurately simulate the velocity gradient and shear stress distribution near the wall, ensuring the reliability of the blood flow simulation.

[0046] Step 2: Set boundary conditions. In ANSYS Fluent, set the boundary parameters of the fluid domain through the boundary conditions panel. Generally, the settings for each boundary location are shown in Table 1 below:

[0047]

[0048] The superior vena cava inlet was set as a velocity inlet following a pulsating waveform to simulate periodically changing blood flow input; the corresponding outlet was set as a pressure outlet with a fixed reference value to characterize the downstream flow environment. The blood material properties were set as an incompressible Newtonian fluid, with density and dynamic viscosity selected from typical blood values. Finally, a transient solver was used for calculation, with its time step appropriately selected based on the flow characteristics to accurately capture the dynamic changes in the flow field.

[0049] Step 3: Blood Flow Velocity Field Calculation. In ANSYS Fluent, this is achieved by numerically solving the incompressible Navier-Stokes equations using a laminar flow model. These governing equations are built into the software's solver kernel, and their general form is as follows:

[0050] ;

[0051] In the formula u is the velocity vector. For pressure, For dynamic viscosity, Represents the local acceleration term. Represents the convective acceleration term. Represents pressure gradient force. It represents viscous force.

[0052] After setting the boundary conditions and the Navier-Stokes equations, the software will discretize the computational domain based on the finite volume method and use a corresponding numerical algorithm (such as SIMPLE) to iteratively solve the discretized equations, finally outputting the velocity distribution of the entire flow field over a complete cycle.

[0053] Furthermore, eddy current analysis and flow weight construction are performed, including:

[0054] A dynamic weighting function based on eddy current and pulsation characteristics is introduced to enhance the hydrodynamic calculation of the recirculation rate of hemodialysis catheters. The enhanced hydrodynamic calculation includes: eddy current intensity calculation, superimposed eddy current intensity calculation, and flow rate weighting calculation.

[0055] Furthermore, the eddy current intensity calculation includes:

[0056] eddy current intensity V i The modulus defined as the curl of the velocity field According to the formula: Calculate the curl component, where, Here, u is the curl operator, and u is a three-dimensional velocity vector, where u x u y u z These represent the components of velocity in the x, y, and z directions of the Cartesian coordinate system, respectively, where i, j, and k are unit vectors in the coordinate directions.

[0057] Therefore, we get: .

[0058] In practical applications, to analyze the characteristics of different regions, the computational domain is generally divided into a side-hole region and a tip region: the corresponding mesh is extracted in the side-hole region and the average eddy current intensity is calculated. The average eddy current intensity is calculated using a mesh near the tip. All eddy current intensity data are averaged over a complete cycle to reflect the steady-state characteristics under periodic pulsating flow conditions.

[0059] Furthermore, the calculation of the superimposed eddy current intensity includes:

[0060] Total eddy current intensity V i,total Equal to the eddy current intensity in the side hole region With the intensity of eddy currents in the tip region sum.

[0061] Specifically, according to the formula: Assuming the intensity of the tip eddy current Side hole eddy current intensity Substituting the assumed values ​​into the formula yields the following results. This eddy current intensity parameter has a clear regional specificity, being assigned only to the two key regions of the side holes and the tip. Generally, it is uniformly set to zero in other regions of the model. .

[0062] Furthermore, the traffic weight calculation includes:

[0063] According to the formula: Calculate the flow weighting factor w, where Qmax is the maximum flow, Qmin is the minimum flow, and k1 and k2 are weighting coefficients.

[0064] In one embodiment, , Take weighting coefficients Substituting into the formula, we get: w=0.6*60+0.4*((4920-1011) / 4920)=36+0.3176≈36.32.

[0065] Furthermore, the calculation of the recirculation rate includes:

[0066] According to the formula: The recirculation rate RR is obtained by volume integral of the local recirculation probability density, where N returned To return the number of particles in the arterial lumen, N returned V represents the number of particles released, and V represents the volume of the blood flow region.

[0067] In practical applications, traditional recirculation rate (RR) calculations cannot reflect dynamic factors such as vorticity and vortex intensity. This method introduces a weighting function w into the calculation formula, along with the transient flow rate Q(t) and local pressure gradient under pulsating flow conditions, into the RR measurement system. This allows the formula to automatically increase the contribution weight of the high-vortex region and reduce the influence of weak vortices or stable regions. The setting of the weighting function enables the RR calculation to not only reflect the change in the number of recirculating particles but also the amplification effect of turbulent structures on the recirculation behavior, realizing a fundamental transformation of the recirculation rate from a statistical phenomenon to a dynamically driven phenomenon.

[0068] This method extends the recirculation rate (RR) from a traditional global statistical model to a volumetric distributed representation. By integrating the proportion of refluxing particles in a volumetric manner across the entire pericatheter blood flow region, RR is no longer a single measurement point or a global average result, but a three-dimensional quantitative indicator reflecting the contribution of different spatial locations to refluxing. By... As a local backflow probability density, and continuously calculated within volume V, it forms a fine-grained characterization of the backflow behavior in the side holes, tip, and turbulent core region, which can fully express the true contribution of the local flow structure of the duct to RR.

[0069] During the recirculation rate calculation, after obtaining the blood viscosity model and solving the non-Newtonian flow field, the particle motion within the hemodialysis catheter was accurately tracked using the discrete phase model in ANSYS Fluent. Based on the converged flow field data, particle release parameters were set, and tracer particles were released from the catheter venous inlet with initial conditions matching the local flow field. The particle motion follows Newton's second law, and its trajectory is determined by solving the differential equations of motion. In the formula The position vector of the particle describes the instantaneous coordinates of the tracer particle in three-dimensional space; The velocity vector of the particle describes its instantaneous velocity in three-dimensional space.

[0070] This method integrates microscopic vortex structures with macroscopic flow fields through a volume integral RR calculation framework, making the recirculation rate (RR) a predictable hemodynamic indicator. It projects the local backflow contributions from different regions onto the overall RR value, achieving consistency and comparability on a global scale. The microscopic vortex structures include: side-hole confluence shear layers, tip jet backflow vortices, and secondary flow vortices. The macroscopic flow field includes: mainstream velocity distribution, pulsating waveforms, and vascular geometric constraints.

[0071] In practical applications, a "vortex intensity-RR" correlation model based on multi-dimensional parameters such as vortex field and vortex identification criteria can be constructed to couple the detailed changes of local vortices with the overall recirculation trend, enabling the local three-dimensional flow field characteristics of different regions of the catheter to be integrated and reflected macroscopically. Through parameterized processing of complex regions such as side-hole jets, tip jets, and mutual interference between dual lumens, a holistic, structured, and predictable analysis of the entire catheter hemodynamic state can be achieved, revealing the distribution patterns of overall flow trends, local risk areas, and the probability of recirculation. Organically integrating local features with global trends allows catheter designers to predict RR changes at an early stage through vortex intensity, enabling forward-looking judgments for design optimization and significantly improving the reliability and scientific rigor of hemodialysis catheter design, evaluation, and clinical application.

[0072] Furthermore, the present invention also provides a computer device, the device comprising: a memory and a processor; the memory for storing a computer program; the processor executing the computer program to implement the steps of the above-described method. The processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, operations, and logic block diagrams disclosed in the embodiments of this disclosure. The general-purpose processor can be a microprocessor or any conventional processor, and can be based on an x86 architecture or an ARM architecture.

[0073] Generally, various exemplary embodiments of the present invention can be implemented in hardware or dedicated circuitry, software, firmware, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. When aspects of embodiments of the present invention are illustrated or described as block diagrams, flowcharts, or using some other graphical representation, it will be understood that the blocks, apparatuses, systems, techniques, or methods described herein can be implemented as non-limiting examples in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0074] The present invention also provides a computer-readable storage medium, wherein in one embodiment the computer-readable storage medium may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM) used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous interconnected dynamic random access memory (SLDRAM), and direct memory bus random access memory (DR RAM). It should be noted that the memory of the methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0075] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method.

[0076] Therefore, this invention provides a method, device, medium, and program product for clinical evaluation of hemodialysis catheter performance. It models and simulates the hemodialysis catheter and superior vena cava, integrates the proportion of reflux particles in the entire blood flow region surrounding the catheter using a volume integral method, performs eddy current analysis and weighting, and calculates the recirculation rate. This addresses the problem of insufficient accuracy in existing clinical evaluations of hemodialysis catheter performance, which fails to meet the needs of precision medicine. It improves the accuracy of estimating the recirculation rate of hemodialysis catheters and provides theoretical guidance for optimizing hemodialysis catheter performance.

[0077] The structure, features, and effects of the present invention have been described in detail above with reference to the embodiments shown in the figures. The above description is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or equivalent embodiments modified to have equivalent changes, shall be within the protection scope of the present invention as long as they do not exceed the spirit covered by the specification and figures.

Claims

1. A clinical evaluation method for the performance of hemodialysis catheters, characterized in that, include: Geometric modeling of hemodialysis catheters and superior vena cava; High-precision mesh generation and blood flow simulation were performed on the geometric models of hemodialysis catheters and superior vena cava. Boundary conditions are set for each boundary of the fluid domain in the geometric model, and eddy current analysis and flow weight construction are performed. By tracking particles within the hemodialysis catheter, the proportion of returning particles is integrated in a volume integral manner throughout the blood flow area surrounding the catheter, and the recirculation rate is calculated.

2. The clinical evaluation method for the performance of hemodialysis catheters according to claim 1, characterized in that, The geometric modeling of the hemodialysis catheter and superior vena cava includes: Using SolidWorks software and its parametric modeling function, a geometric model of the hemodialysis catheter and superior vena cava was constructed. The geometric model includes key features such as a dual-lumen design, side holes, distal end, and tip.

3. The clinical evaluation method for the performance of hemodialysis catheters according to claim 2, characterized in that, The high-precision mesh generation and blood flow simulation of the geometric model of the hemodialysis catheter and superior vena cava include: The duct model is discretized with high precision using a polyhedral mesh, and local mesh refinement is implemented for key flow regions, including: the side hole surface, the inner wall of the lumen, and the tip region. A boundary layer mesh is set at the fluid-solid interface to accurately simulate the velocity gradient and shear stress distribution in the near-wall region, ensuring the reliability of blood flow simulation.

4. The clinical evaluation method for the performance of hemodialysis catheters according to claim 3, characterized in that, The high-precision mesh generation and blood flow simulation of the geometric model of the hemodialysis catheter and superior vena cava also includes: The incompressible Navier-Stokes equations corresponding to the geometric models of the hemodialysis catheter and superior vena cava were numerically solved using a laminar flow model to obtain the blood flow velocity field distribution over a complete cycle.

5. The clinical evaluation method for the performance of hemodialysis catheters according to claim 4, characterized in that, Setting boundary conditions for each boundary of the fluid domain in the geometric model includes: The superior vena cava inlet is set as a velocity inlet that follows a pulsatile waveform to simulate periodically changing blood flow input; The corresponding outlet is set as a pressure outlet with a fixed reference value to characterize the downstream flow environment; The properties of the blood material were set as an incompressible Newtonian fluid, with density and dynamic viscosity selected from typical values ​​of blood.

6. The clinical evaluation method for the performance of hemodialysis catheters according to claim 5, characterized in that, The process of performing eddy current analysis and flow weight construction includes: A dynamic weighting function based on eddy current and pulsation characteristics is introduced to enhance the hydrodynamic calculation of the recirculation rate of hemodialysis catheters. The enhanced hydrodynamic calculation includes: eddy current intensity calculation, superimposed eddy current intensity calculation, and flow rate weighting calculation. The eddy current intensity calculation includes: eddy current intensity V i The modulus defined as the curl of the velocity field According to the formula: Calculate the curl component, where, Here, u is the curl operator, and u is a three-dimensional velocity vector, where u x u y u z These represent the components of velocity in the x, y, and z directions of the rectangular coordinate system, respectively, where i, j, and k are unit vectors in the coordinate directions; The calculation of the superimposed eddy current intensity includes: Total eddy current intensity V i,total Equal to the eddy current intensity in the side hole region With the intensity of eddy currents in the tip region sum; The traffic weight calculation includes: According to the formula: Calculate the traffic weighting factor w, where Q max For maximum flow, Q min k1 and k2 are weighting coefficients for the minimum flow rate.

7. The clinical evaluation method for the performance of hemodialysis catheters according to claim 6, characterized in that, The calculation of the recirculation rate includes: According to the formula: The recirculation rate RR is obtained by volume integral of the local recirculation probability density, where N returned To return the number of particles in the arterial lumen, N returned V represents the number of particles released, and V represents the volume of the blood flow region.

8. A computer device, characterized in that, The device includes: a memory and a processor; the memory is used to store a computer program; the processor executes the computer program to implement the steps of the method according to any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the steps of the method as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the steps of the method described in any one of claims 1-7.

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