A pulsatile blood flow circulation loop experimental table simulating a cardiovascular system and a test method

Abstract

This application provides an experimental setup and testing method for simulating a pulsating blood flow circulation loop in a cardiovascular system. The experimental setup includes: a circulation loop module for providing a fluid channel for circulating flow in an isolated aorta; a pulsation control module for simulating the pulsation caused by a heartbeat; and a model adaptation module for fixing the isolated aorta and simulating its original environment in a living organism. The advantages of this application are: high-precision reproduction of pulsating waveforms under multiple physiological / pathological conditions; significantly improved adaptability and biomimicry in pathological scenarios; and continuous dynamic adjustment and efficient collaborative control of loop parameters.

Description

Technical Field

[0001] This application belongs to the fields of biomedical engineering, in vitro cardiovascular simulation and vascular disease testing technology, specifically involving a pulsating blood flow circulation circuit experimental platform and testing method for simulating the cardiovascular system, which is suitable for the construction of a pulsating blood flow circulation circuit experimental platform for the study of the pathological mechanism of aortic disease. Background Technology

[0002] The aorta is a vital blood vessel in the human circulatory system, responsible for transporting high-pressure, high-flow-rate blood. Its mechanical state and hemodynamic environment directly affect the normal functioning of the cardiovascular system. Aortic diseases such as aortic dissection, aortic aneurysm, and arteriosclerosis are characterized by insidious onset, rapid progression, and high mortality. Once the vessel wall undergoes abnormal dilation, tearing, or rupture, it can lead to severe circulatory disorders and even endanger life. Therefore, studying the hemodynamic changes, vessel wall stress state, and active vascular contraction regulation mechanisms during the development of aortic diseases is of great significance for disease risk assessment, treatment optimization, and medical device testing.

[0003] Currently, research methods for understanding the pathological mechanisms of aortic disease mainly include numerical simulation, in vivo animal experiments, and extracorporeal circulation experiments. Among these, finite element simulation and computational fluid dynamics simulation can be used to analyze parameters such as vessel wall stress distribution, blood flow velocity field, and pressure changes, offering advantages such as flexible modeling, low cost, and adjustable parameters. However, these methods typically require simplified assumptions about vessel geometry, material properties, boundary conditions, and the biomechanical behavior of the vessel wall, making the results susceptible to influences from model accuracy and parameter settings. Furthermore, they lack direct validation with real tissue and experimental data. In vivo animal experiments can more realistically reflect the response of vascular tissue under physiological conditions, but they suffer from complex ethical approval processes, high experimental costs, significant individual variability, difficulty in precisely controlling experimental conditions, and poor reproducibility.

[0004] In contrast, in vitro pulsatile blood flow circulation test benches can simulate pressure, flow, and pulsatile blood flow changes in the human cardiovascular system under controlled conditions, providing an experimental method between numerical simulation and in vivo experiments for the study of aortic disease mechanisms. These test benches typically consist of a pulsatile pump, a reservoir, a compliance adjustment unit, a resistance simulation unit, an experimental blood vessel segment, and pressure and real-time measurement devices. The pulsatile pump simulates the periodic ejection process of the heart, the compliance adjustment unit simulates the elastic energy storage function of large blood vessels, the resistance simulation unit simulates peripheral vascular resistance, and pressure and flow sensors are used to collect hemodynamic parameters in the circulation loop in real time. By adjusting parameters such as pump stroke volume and frequency, loop resistance, and compliance, physiological environments with different blood pressure, flow, and pulsatile characteristics can be constructed in vitro.

[0005] Therefore, it is necessary to construct a pulsatile blood flow circulation circuit experimental platform suitable for the study of the pathological mechanism of aortic disease, so that it can simulate key physiological factors such as cardiac ejection, peripheral resistance, and vascular compliance in an in vitro controlled environment, and realize the synchronous monitoring of pressure, flow and vascular state parameters. This will provide a more stable, repeatable and controllable experimental platform for the study of aortic disease mechanism, evaluation of vascular mechanical performance and related medical device testing.

[0006] However, existing experimental setups and testing methods for simulating the pulsating blood flow circulation loop of the human cardiovascular system have the following shortcomings when used for aortic-related research: First, the accuracy of pulsation waveform simulation is insufficient. Existing experimental platforms often use pulsation pumps driven by fixed parameters or preset programs, making it difficult to accurately reproduce the blood flow pressure waveforms in the human body under different physiological or pathological states, such as dynamic pressure changes under normal blood pressure, hypertension, and high heart rate. This leads to discrepancies between in vitro simulation results and the actual pathological evolution process in the human body, affecting the authenticity and reliability of experimental results.

[0007] Second, the adaptability to pathological scenarios is poor. Traditional in vitro experimental platforms mostly use silicone artificial blood vessel models. These silicone models lack the layered information of the real aorta and do not have the fiber network formed by the interweaving of elastic and collagen fibers, making it impossible to reproduce the inherent mechanical behavior of blood vessels and reveal the essential laws of aortic dissection progression. In addition, existing experimental methods have not been designed to take into account the individualized anatomical and hemodynamic characteristics of patients with aortic dissection and aortic aneurysm, and lack targeted testing protocols for the correlation between changes in pressure in the true and false lumens, blood flow distribution characteristics, and dissection expansion behavior, making it difficult to meet the needs of systematic research on the expansion laws of aortic dissection under different pathological conditions.

[0008] Third, the flexibility of loop parameter adjustment is insufficient. In existing experimental setups, the collaborative control capability between components such as the compliance adjustment unit and the resistance simulation unit and the pulsating pump is weak, making it difficult to achieve continuous and dynamic adjustment of loop parameters. Therefore, when switching between different simulated conditions such as normal blood pressure, high blood pressure, and high heart rate, complex and repetitive calibrations are often required, resulting in low experimental efficiency.

[0009] The applicant believes that the main reason for the above-mentioned technical defects is that the existing technology has not established a precise correspondence between "pressure waveform - pathological state - disease progression behavior", and the pulsation control method is not well matched with the hemodynamic characteristics of the human body. At the same time, the key components such as compliance chambers and resistance adjustment components in the circulatory loop have not fully considered the in vitro testing requirements of the aortic model in terms of structural design and control logic, resulting in a disconnect between the circuit parameter regulation and the simulation of the disease progression process. Summary of the Invention

[0010] The purpose of this application is to overcome the shortcomings of existing technologies, such as inaccurate simulation of pulsating waveforms, poor adaptability to pathological scenarios, and insufficient flexibility in circuit control.

[0011] To achieve the above objectives, this application proposes an experimental platform for simulating a pulsating blood flow circulation loop in a cardiovascular system, comprising: A circulation loop module is used to provide a fluid channel for circulating flow in an isolated aorta; The pulsation control module is used to simulate the pulsation of a heartbeat in the flow of fluid; and The model adaptation module is used to fix the isolated aorta and simulate the original environment of the isolated aorta in a living organism.

[0012] As an improvement to the aforementioned experimental platform, the loop module includes: A liquid storage tank is used to store circulating fluids. A piston pump is used to draw fluid from the reservoir and pump it into the fluid channel; A check valve, connected in series in the channel, is used to prevent fluid from flowing backward in the channel; Compliant chambers, connected in series in the channel, are used to buffer fluid pressure fluctuations, mimicking the elastic compliance characteristics of blood vessels; A pressure sensor, connected in series in the channel, is used to measure the pressure of the fluid in the channel; A flow sensor, connected in series in the channel, is used to measure the flow rate of the fluid in the channel; A resistance regulator, connected in series in the channel, is used to adjust the channel's resistance to the fluid, thereby changing the fluid's flow rate and pressure; and Silicone tubing is used to connect the various components of the circulation loop module and the isolated aorta in series to form a closed fluid channel.

[0013] As an improvement to the above-mentioned experimental setup, the isolated aorta preservation includes four openings: the proximal end of the ascending aorta, the distal end of the descending thoracic aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch; all other openings are closed. The proximal end of the ascending aorta is the fluid inlet; the distal end of the descending aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch are the fluid outlets; The one-way valve, compliant chamber, pressure sensor, flow sensor, and resistance regulator are all in sets of two. The outlet of the piston pump is connected to the proximal end of the ascending aorta through the silicone tube to form an inlet channel; a one-way valve, a compliance chamber, a pressure sensor, a flow sensor and a resistance regulator are connected in series on the inlet channel; The distal end of the descending thoracic aorta is connected to the inlet of the reservoir via the silicone tube to form an outlet channel; a compliance chamber, a pressure sensor, a flow sensor, and a resistance regulator are connected in series on the outlet channel; A one-way valve is connected in series between the outlet of the liquid storage tank and the inlet of the piston pump; The bow head arm is directly connected to the inlet of the liquid storage tank via a silicone tube; The left subclavian artery in the arch is connected to the outlet channel via a silicone tube.

[0014] As an improvement to the aforementioned experimental setup, the piston pump includes: a lead screw, a piston, a cylinder, and a ventricular cavity; wherein, The cylinder barrel is a hollow cylinder; The lead screw is connected to the piston at one end and is driven by a motor to make the piston reciprocate in the cylinder. The piston is located in the cylinder, and its side is pressed against the inner wall of the cylinder. Through reciprocating motion, it creates pulsating pressure on the fluid in the cylinder. The ventricular cavity is a hollow shell with three openings. The first opening is connected to one end of the cylinder. The second and third openings serve as the fluid inlet and outlet of the piston pump, respectively. The axes of the second and third openings form a 50-degree angle.

[0015] As an improvement to the aforementioned experimental platform, the pulse control module includes: An electric motor is used to provide power to the piston pump; A servo driver, connected to the motor, is used to drive the motor to run according to a set pattern; The PLC controller is connected to the servo driver and is used to generate control commands based on set parameters and output them to the servo driver. Input terminal device, used to receive control parameters input by the user and output the control parameters to the PLC controller; and A power supply is provided to power the various components of the pulse control module.

[0016] As an improvement to the aforementioned experimental platform, the model adaptation module includes: A support box is used to hold an isolated aorta; the bottom of the support box is provided with a sponge pad with an arc-shaped groove, which matches the shape of the aorta and provides flexible support for the blood vessel, simulating the support and wrapping of the aorta by the surrounding muscle tissue.

[0017] This application provides a method for testing a pulsating blood flow circulation loop in a simulated cardiovascular system, implemented based on the aforementioned test bench, including: Step 1: Pre-treat the isolated aorta to form a false lumen, and connect the isolated aorta to the test bench; Step 2: Keep the input blood pressure constant, increase the heart rate in a stepwise manner, and obtain the relationship between heart rate and false lumen blood pressure; keep the input heart rate constant, increase the input blood pressure in a stepwise manner, and obtain the relationship between input blood pressure and false lumen blood pressure. Step 3: Experiments were conducted on blood vessels with initial false lumens of different thicknesses, circumferential lengths, and axial lengths to measure the dissection expansion pressure and obtain the relationship between the expansion pressure and the morphological parameters of the false lumen.

[0018] As an improvement to the above method, the pretreatment of the isolated aorta to form a false lumen in the isolated aorta includes: Freshly obtained aortas or aortas that have been cryopreserved and then thawed are selected, retaining the ascending aorta to the descending thoracic aorta segment and removing the fat attached to the outside. Only four entry and exit points for fluid flow were preserved on the aorta: the proximal end of the inferior ascending aorta, the distal end of the descending thoracic aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch. All other branch vessels were closed. The aorta is radially flipped so that the intima faces outward and the adventitia faces inward. At the distal end of the left subclavian artery in the arch, a non-penetrating incision is made in the intima using a scalpel. This incision is then enlarged circumferentially to construct the initial incision. Blunt forceps are then inserted into the medial layer through the initial intimal incision and blunt dissection is performed along the long axis of the aorta to form an artificial false lumen with a set axial length and circumferential range. The aorta will be restored to its original physiological form with the adventitia on the outside.

[0019] As an improvement to the above method, the pretreatment of the isolated aorta further includes: A pressure guidewire is inserted from the left subclavian artery in the arch and placed inside the false lumen to measure blood pressure at different locations within the false lumen.

[0020] As an improvement to the above method, the pretreatment of the isolated aorta further includes: The thickness of the aortic intima patch, the circumferential length of the false lumen, and the axial length were measured; the measurement methods included: Place a graduated ruler on the same plane as the location to be measured, take a picture vertically with a camera, and obtain the measured value based on the graduations on the ruler as a standard ratio.

[0021] Compared with existing technologies, the advantages of this application are: 1. Achieved high-precision reproduction of pulsating waveforms under multiple physiological / pathological states. This application breaks through the limitations of traditional pulsating pumps driven by fixed parameters, and can accurately simulate the dynamic pressure waveforms of the human body under various complex physiological and pathological states such as normal blood pressure, hypertension, and high heart rate. Through real-time correction, it ensures that the simulated blood flow pressure waveform in vitro is highly consistent with the actual pathological evolution process in the human body, thereby eliminating waveform deviations in traditional experiments and greatly improving the authenticity and reliability of experimental data.

[0022] 2. Significantly improved adaptability and biomimicry in pathological scenarios. This application introduces real animal blood vessels as test models, replacing traditional silicone artificial blood vessels. Real blood vessels retain their complete layered structure and natural fiber network formed by the interweaving of elastic and collagen fibers, realistically replicating the inherent mechanical behavior of blood vessels, thereby effectively revealing the essential progression law of aortic dissection. Furthermore, this application supports targeted modeling based on individualized anatomical features and hemodynamic characteristics of patients, enabling in-depth exploration of the intrinsic correlation between changes in true and false lumen pressure, blood flow distribution characteristics, and dissection expansion behavior, meeting the systematic research needs of aortic dissection expansion laws under different pathological conditions.

[0023] 3. Continuous dynamic adjustment and efficient coordinated control of loop parameters are achieved. This application supports continuous and dynamic adjustment of loop parameters, eliminating the need for tedious repetitive calibration when switching between different simulated conditions such as normal blood pressure, high blood pressure, and high heart rate. This improvement not only significantly enhances experimental efficiency but also provides a more flexible and convenient testing method for studying vascular lesions under complex hemodynamic environments. Attached Figure Description

[0024] Figure 1 The diagram shows the components of an experimental setup simulating a pulsating blood flow circulation loop in a cardiovascular system; the blue arrows indicate the direction of liquid flow in the channels. Figure 2 The diagram shown is a structural diagram of the drive unit module. Figure 3 The image shown is a 3D model of a piston pump. Figure 4 The image shown is a 3D model of the piston. Figure 5 The image shown is a 3D model of the cylinder. Figure 6 The image shown is a three-dimensional model of the ventricular cavity; Figure 7 The image shown is a 3D model of the flange. Figure 8 The image shown is a 3D model of the support box; Figure 9 The image shown is a three-dimensional model of the compliant chamber.

[0025] Attached image labels: 1. Liquid storage tank 2. First check valve 3. Piston pump 4. Second check valve 5. First compliant chamber; 6. First pressure sensor 7. First flow sensor 8. First ball valve 9. Isolated aorta; 10. Second ball valve 11. Second pressure sensor 12. Second flow sensor 13. Compliant chamber 14. Power supply 15. Touch screen 16. PLC controller 17. Servo driver 18. Motor 19. Support box 191. Connecting groove 301, Lead Screw; 302, Piston 303, cylinder barrel; 304, flange 305. Ventricular cavity 901. Proximal end of the ascending aorta; 902. Distal end of the descending thoracic aorta. 903. Brachiocephalic trunk in the arch region; 904. Left subclavian artery in the arch region. Detailed Implementation

[0026] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0027] This application provides an experimental platform and testing method for simulating the pulsatile blood flow circulation loop of the cardiovascular system, which can accurately reproduce the blood flow pressure waveform under different physiological states of the human body, accurately simulate the progression of aortic diseases, and provide a reliable in vitro experimental platform for the study of the mechanism of aortic-related diseases. It can achieve accurate reproduction of pulsatile pressure waveform and dynamic coordinated control of circulation loop parameters, and can be adapted to the in vitro experimental needs of artificial blood vessels and isolated large animal blood vessels, especially porcine aortic models, thereby improving the shortcomings of existing experimental platforms in terms of pulsatile waveform simulation accuracy, adaptability to pathological scenarios, and flexibility of loop parameter control.

[0028] Example 1 The pulsating blood flow circulation loop experimental platform for simulating a cardiovascular system provided in this application includes a pulsation control module, a circulation loop module, and a model adaptation module.

[0029] like Figure 2As shown, the pulsation control module is used to simulate the pulsation of a heartbeat in fluid flow. It includes: a power supply 14, a motor 18, a servo driver 17, a PLC controller 16, and a touchscreen 15. The power supply 14 provides power to the touchscreen 15, motor 18, servo driver 17, and PLC controller 16. The PLC controller 16 can be an Easy521-0808TN model or another controller with similar functions. In other embodiments, the touchscreen can also be any other input device capable of receiving user input and displaying parameters.

[0030] like Figure 1 As shown, the circulation loop module provides a fluid channel for circulatory flow in the aorta. It includes: a piston pump 3, a first compliance chamber 5, a second compliance chamber 13, a first resistance regulator 8, a second resistance regulator 10, a first flow sensor 7, a second flow sensor 12, a first pressure sensor 6, a second pressure sensor 11, a reservoir 1, a first check valve 2, a second check valve 4, and connecting pipes. The first compliance chamber 5 and the second compliance chamber 13 simulate the elastic compliance characteristics of human blood vessels; the first resistance regulator 8 and the second resistance regulator 10 adjust the resistance of the circulation loop by changing the flow channel opening; the first flow sensor 7, the second flow sensor 12, the first pressure sensor 6, and the second pressure sensor 11 are used to collect flow and pressure data in the circulation loop in real time to achieve dynamic monitoring of the extracorporeal circulation status. The first resistance regulator 8 and the second resistance regulator 10 can be ball valves or other flow-adjustable devices.

[0031] The model adapter module is a vascular model fixation device used to mount the isolated aortic model. The vascular model fixation device is sealed to the inlet and outlet ends of the circulation loop to ensure stable and closed-loop circulation of simulated blood in the circulation loop and the isolated vascular model.

[0032] The setup process for the experimental platform is as follows: S1: Drive unit connection: The touchscreen 15 is communicatively connected to the PLC controller 16 for inputting and displaying control parameters such as heart rate, stroke volume, systolic phase percentage, and start / stop. The PLC controller 16 is connected to the servo driver 17 for generating corresponding control commands based on the parameters input from the touchscreen 15. The servo driver 17 is connected to the servo motor 18 for driving the servo motor 18 to operate according to a preset pattern. The servo motor 18 is further connected to a lead screw drive, which drives the piston to perform periodic reciprocating motion within the piston cylinder.

[0033] S2: Piston pump assembly: like Figure 3 As shown, the piston pump 3 includes a lead screw 301, a piston 302, and a cylinder 303 (as shown). Figure 5(As shown), ventricular cavity 305 and flange 304. Motor 18 provides driving force to lead screw 301. Lead screw 301 has a lead of 10 mm and an effective stroke of 100 mm. Based on the effective cross-sectional area of ​​piston cylinder 303, controlling lead screw 301 to drive piston 302 to complete a single effective displacement of 50 mm can achieve a simulated stroke volume of approximately 250 mL. A standard YCC sealing ring is clamped in the sealing ring groove of piston 302. Piston 302 is made of 45 steel, and its rear side is provided with an internal thread groove, which is connected to lead screw 301 through the internal thread groove, thereby realizing the reciprocating motion of piston 302 under the drive of lead screw 301.

[0034] The piston cylinder 303 is made of industrial-grade standard SC80 mm diameter cylinder barrel. Two through holes are opened on the upper side of the cylinder 303 near its edge. The through hole near the lead screw 301 is used to discharge gas from inside the cylinder 303, and the through hole near the ventricular cavity 305 is used for initial liquid injection, partial venting, and subsequent cleaning and maintenance of the pulse pump's working chamber. An auxiliary liquid injection and venting interface is provided on the upper part of the piston cylinder. During the filling process, the gas retained in the working chamber above the piston 302 is discharged through this interface to reduce the impact of gas compressibility on the pump's output pressure and volumetric accuracy. During normal operation, a threaded plug is used to seal it. The sealing ring has a good sealing fit with the cylinder wall, possessing advantages such as low frictional resistance and strong wear resistance, thereby improving the reliability and stability of the pulse pump device.

[0035] like Figure 6 As shown, the ventricular cavity 305 is made of acrylic material and has two simulated valve installation channels arranged symmetrically at 50° angles with an inner diameter of 45 mm inside. The upper and lower ends of the ventricular cavity 305 are respectively provided with threaded through holes, which are connected to a pagoda connector via threads. The upper through hole is located at the high position of the cavity and connects to an exhaust branch. During fluid injection, air in the cavity rises and is discharged through the exhaust branch connected to this through hole. Once the exhaust branch continuously flows out without air bubbles, it is closed. The exhaust branch can then be connected to a pressure sensor. The pressure inside the ventricular cavity 305 is transmitted to the sensor through a liquid-filled pressure measuring tube, achieving real-time pressure measurement. The pagoda connector connected to the lower through hole is in a closed state during operation. When it is necessary to replace or drain the fluid from the ventricular cavity, it can be opened for rapid drainage. A sealing ring is provided on the rear end face of the ventricular cavity and is fixedly connected to the flange 304 by bolts to ensure the sealing of the connection between the ventricular cavity 305 and the piston cylinder 303.

[0036] S3: Connections between components: During the experiment, the isolated animal aorta was placed in a self-made rectangular support box 19, which was made of PLA material. Figure 8As shown, the three side walls of the support box 19 have strip-shaped through-hole silicone tube connection slots 191 to facilitate connection between the two ends of the aorta and the external circulation pipeline. The connection slot 191 on the long side of the support box 19 is for the proximal end 901 of the ascending aorta, the connection slot 191 on one short side is for the distal end of the descending thoracic aorta, and the connection slot 191 on another short side is for the brachiocephalic trunk 903 and the left subclavian artery 904 in the arch. A sponge pad with an arc-shaped groove is placed inside the support box 19. The groove matches the shape of the aorta and can provide flexible support for the blood vessel. It is used to simulate the support and wrapping of the aorta by the surrounding muscle tissue, so as to avoid significant displacement, torsion or local damage to the aorta caused by hard contact under the impact of pulsating flow.

[0037] The in vitro simulated circulation loop includes a piston pump 3, a first compliance chamber 4, a second compliance chamber 13, a first resistance regulator 8, a second resistance regulator 10, a first flow sensor 7, a second flow sensor 12, a first pressure sensor 6, a second pressure sensor 11, a reservoir 1, a first one-way valve 2, a second one-way valve 4, an animal aorta 9, and connecting silicone tubing. During connection, the reservoir 1 serves as a storage and return unit for the circulating fluid, and its outlet is connected sequentially to the inlet of the first one-way valve 2 and the piston pump 3 via silicone tubing. The piston pump 3 serves as the circulation power source, generating pulsating flow through periodic reciprocating motion, and sequentially delivering the circulating fluid through the second one-way valve 4, the first compliance chamber 5, the first pressure sensor 6, the first flow sensor 7, and the first resistance regulator 8 to the proximal end of the aorta (proximal end of the ascending aorta 901). The distal aortic outlet (distal end of the descending thoracic aorta 902) is connected sequentially to the second resistance regulator 10, the second pressure sensor 11, the second flow sensor 12, and the second compliance chamber 13 via silicone tubing, ultimately returning to the reservoir 1 to form a closed extracorporeal pulsating circulation loop. The brachiocephalic trunk 903 of the aorta 9 is connected to the reservoir 1 via silicone tubing. The left subclavian artery 904 of the aorta 9 is connected to the silicone tubing between the second pressure sensor 11 and the second flow sensor 12 via silicone tubing. The second flow sensor 12 is installed in series in the tubing after the aortic outlet to record the circulation flow waveform; the second resistance regulator 10 is located at the return end and serves as an adjustable peripheral impedance element, adjusting the flow area of ​​the tubing by changing the valve opening, thereby changing the circulation loop resistance and regulating the pressure level within the aorta. All silicone tubing connections are secured with iron hoops to improve the sealing and resistance to pulsating impacts, preventing leakage, tubing detachment, or gas entry into the circulation loop during the experiment.

[0038] like Figure 9As shown, both the first compliance chamber 5 and the second compliance chamber 13 are made of PETG material and have an overall cylindrical structure. Pipe interfaces are located on both sides of the lower part of the chambers for connecting to the circulating silicone tubing and integrating into the extracorporeal circulation loop; a liquid injection interface is located at the top for injecting circulating fluid into the chambers before the experiment and adjusting the liquid-to-gas ratio. During the experiment, liquid is injected into the compliance chambers while maintaining a certain volume of gas in the upper part of the chambers. Due to the compressibility of gas, this gas chamber can be compressed and rebounded under the action of pulsating flow, thereby buffering pressure fluctuations, improving system compliance, and making the circulation loop more closely resemble the elastic blood storage characteristics of the arterial system.

[0039] S4: Parameter calibration and pathological state adaptation: During parameter calibration, the circulation loop is first filled with fluid, vented, and its sealing is checked to ensure continuous fluid flow in the pipeline, aorta, compliance chamber, and reservoir, preventing residual air bubbles from affecting the pressure and flow waveforms. The resistance regulator is then adjusted to a medium opening as the initial impedance state, and a lower heart rate and smaller stroke volume are set on the touchscreen 15 control interface to start the piston pump 3 under low load. After stable operation, the flow waveform of the aorta 9 and the pipeline operating status are observed before gradually adjusting to the target operating condition.

[0040] Different case conditions are mainly achieved by adjusting the output parameters of piston pump 3 and the opening of the resistance regulator. The interface of touch screen 15 is used to set the heart rate, stroke volume, and output waveform of the piston pump. In the experiment, according to the target case condition, the set heart rate, stroke volume, and output waveform are sequentially input on touch screen 15 to make piston pump 3 produce the corresponding simulated cardiac output. The resistance regulator is mainly used to adjust the peripheral impedance of the circulatory system. Since the opening of the resistance regulator is not strictly linearly related to the actual flow resistance, it is not advisable to make a large adjustment at once during the adjustment process. Instead, a small-amplitude, multiple adjustment method should be used, and after each adjustment, the pressure and flow waveforms should be allowed to stabilize before recording the experimental data under that condition.

[0041] In the experiment, corresponding simulated operating conditions were set according to different combinations of hemodynamic characteristics. Under normal operating conditions, moderate heart rate, moderate stroke volume, and moderate resistance regulator opening were set; under hypertensive or high afterload operating conditions, the resistance regulator opening was reduced to increase peripheral impedance while keeping the pump output parameters unchanged or slightly adjusted, thereby increasing the overall systolic and diastolic blood pressure; under high cardiac output conditions, heart rate or stroke volume could be increased; under low cardiac output conditions, heart rate or stroke volume was reduced.

[0042] S5: Test Experiment Plan: Some animal aortas are similar to human aortas in size and mechanical response. Select freshly obtained animal aortas, or animal aortas that have been frozen at deep temperature (-80°C) and then thawed. Use scissors to cut the ascending aorta to the descending thoracic aorta segment, and carefully remove the fat attached to the outside.

[0043] Subsequently, the branches of the descending thoracic aorta were sutured shut, leaving only four entry and exit points for blood flow: the proximal end of the ascending aorta (901), the distal end of the descending thoracic aorta (902), the brachiocephalic trunk (903), and the left subclavian artery (904).

[0044] The aorta is radially flipped so that the intima faces outward and the adventitia faces inward. At the distal end of the left subclavian artery (904) in the arch region, a non-penetrating incision of approximately 0.3 cm width is made in the intima using a scalpel. This incision is then circumferentially enlarged using plastic forceps to construct the initial incision. Subsequently, blunt-tipped plastic forceps are inserted through the initial intimal incision into the medial layer, and blunt dissection is performed along the long axis of the aorta to create an artificial lumen with a predetermined axial length and circumferential range.

[0045] The thickness of the inner membrane, the circumferential length of the false lumen, and the axial length were measured. The measurement method is as follows: A graduated ruler was placed on the same plane at the measurement location, and a camera was used to take a vertical image of the image. Subsequently, the above variables were measured on a computer according to the graduations on the ruler as a standard scale.

[0046] The aorta was restored to its initial physiological morphology with the adventitia external. The openings of the ascending aorta (proximal end 901), descending aorta (distal end 902), brachiocephalic trunk (arch portion) (903), and left subclavian artery (arch portion) (904) were connected to the experimental setup. A silicone tube was inserted into its opening, and the opening and tube were secured with a clamp to prevent fluid leakage. The circulation pump was then turned on to conduct the experiment.

[0047] A pressure guidewire was inserted into the left subclavian artery 904 at the arch and placed inside the false lumen to measure blood pressure at different locations within the false lumen.

[0048] The experimental procedure is as follows: (1) Keep the input blood pressure constant and increase the heart rate stepwise (40, 60, 80, 100, 120, 140, 160, 180 bpm) to obtain the relationship between heart rate and false cavity blood pressure. Observe the dissection expansion before each adjustment.

[0049] (2) Keep the input heart rate constant and increase the input blood pressure in a stepwise manner (40, 60, 80, 100, 120, 140, 160, 180 mmHg) to obtain the relationship between the input blood pressure and the false cavity blood pressure. Observe the dissection expansion before each adjustment.

[0050] (3) Experiments were conducted on blood vessels with different initial lumens thickness, circumferential length and axial length. Pressure guidewires were used to measure the dissection expansion pressure and obtain the relationship between the expansion pressure and the above morphological parameters.

[0051] Example 2 In this embodiment, as Figure 4 As shown, piston 302 is a non-standard part made of 45 steel. Piston 302 has a stepped cylindrical structure with a maximum outer diameter of approximately 79.4 mm, a middle tapering section with an outer diameter of approximately 70 mm, and an upper boss divided into two stages: φ30 mm and φ24 mm. The total height of piston 302 is approximately 66.5 mm, formed by a combination of multiple stepped heights. The center features a threaded structure with a bore diameter of approximately φ15 mm, a cut depth of approximately 28 mm, an effective thread length of approximately 26 mm, and a pitch of approximately 1.5 mm. The edges are chamfered at 2 mm × 45° and have R1 and R2 fillets to reduce sharp corners, facilitate assembly, and ensure smooth force transfer.

[0052] The ventricular cavity 305 is made of acrylic material. Internally, it features two simulated valve installation pathways arranged symmetrically at 50° angles, with an inner diameter of approximately 45 mm. The overall outer dimensions are approximately 141.04 mm × 94.00 mm × 88.00 mm. The main body of the model has an irregular cavity shape, with the central area being the main ventricular cavity region. M10 threaded through holes are located at the upper and lower ends, connecting to a pagoda connector via threads. The pagoda connector has an M10×1 external thread, a thread length of approximately 9 mm, and a lower inner diameter of approximately 6 mm. The pagoda nozzle is approximately 20 mm long with a maximum outer diameter of approximately 10.3 mm, connecting to a silicone tube with an inner diameter of 12 mm and an outer diameter of 16 mm. The central hexagonal section has approximately 12 mm of cross-section for easy wrench installation and tightening. The rear end face of the ventricular cavity 305 has a circular groove with an outer diameter of about 86 mm, an inner diameter of about 80 mm, and a depth of about 1.6 mm. An O-ring with a diameter of 86 mm is placed therein. After being tightened with bolts, it is fixedly connected to the flange 304 to ensure the sealing of the connection between the ventricular cavity 305 and the piston cylinder 303.

[0053] like Figure 7As shown, flange 304 is made of aluminum, with overall dimensions of approximately 260 mm × 30 mm × 220 mm and a plate thickness of approximately 30 mm. Flange 304 features a stepped circular through-hole and annular groove in its center. The central main through-hole has a diameter of approximately φ70 mm, while the outer sides form a multi-level annular groove structure. The larger annular groove has an outer diameter of approximately φ86.5 mm, an inner diameter of approximately φ80 mm, a groove width of approximately 3.25 mm, and a local groove depth of approximately 6 mm. The other annular groove has an outer diameter of approximately φ85 mm, a transition diameter of approximately φ77 mm, and an inner diameter of approximately φ70 mm, forming a stepped transition and positioning groove structure. Flange 304 also has multiple M10 threaded through holes; four holes are located near the outer corners, and the other four are distributed in the central area, for bolt connections.

[0054] like Figure 8 As shown, the support box 19 is made of PLA material. Silicone tube connection grooves 191 are formed on the side wall of the box, located on the two short sides and one long side. The short side groove is approximately 170 mm long and 10 mm wide, while the long side groove is approximately 270 mm long and 10 mm high. This facilitates connection between the two ends of the aorta and external circulation tubing. A sponge pad with an arc-shaped groove is placed inside the box. The groove matches the shape of the aorta, providing flexible support for the blood vessel. This simulates the support and wrapping of the aorta by surrounding muscle tissue, preventing significant displacement, torsion, or local damage caused by hard contact under pulsating flow impact.

[0055] Both the first compliance chamber 5 and the second compliance chamber 13 are made of PETG material, with an overall cylindrical structure, approximately 100 mm in diameter, 160 mm in height, and 3 mm in wall thickness. Pipe interfaces, approximately 30 mm long and 12 mm in outer diameter, are located on both sides of the lower part of the chambers. These interfaces are used to connect silicone tubes with an inner diameter of 12 mm and an outer diameter of 16 mm, and to connect to the extracorporeal circulation circuit. A liquid injection interface, approximately 30 mm long and 12 mm in outer diameter, is located at the top for injecting circulating fluid into the chambers before the experiment and adjusting the liquid-to-gas ratio. During the experiment, liquid is injected into the compliance chambers, while a certain volume of gas is maintained in the upper part of the chambers. Due to the compressibility of gas, this gas chamber can be compressed and rebounded under the action of pulsating flow, thereby buffering pressure fluctuations, improving system compliance, and making the circulation circuit more similar to the elastic blood storage characteristics of the arterial system.

[0056] Because the porcine aorta and the human aorta are highly similar in anatomical and mechanical characteristics such as vascular diameter, wall thickness, elastic modulus, collagen and elastic fiber distribution, compliance, and mechanical response curve, they can realistically reproduce pathological behaviors such as aortic dissection and false lumen expansion in the human aorta. Therefore, porcine aorta was selected as the in vitro experimental material in this embodiment.

[0057] The experiment used fresh pig aortas, or pig aortas that were cryopreserved at -80℃ using a special protective solution and then thawed.

[0058] During the preparation process, a complete aortic specimen is taken, and the ascending aorta to the descending thoracic aorta segment is cut off with scissors. Then, the adipose tissue and connective tissue attached to the outer wall are carefully removed with micro forceps. The entire process must be immersed in physiological saline to avoid drying and damage to the blood vessel wall.

[0059] Subsequently, the branches of the descending thoracic aorta were sealed using non-invasive sutures with a suture spacing of 0.8-1.2 mm to ensure a complete seal and no leakage at the branch vessel openings. After sealing, only four entry and exit points for blood flow were left: the proximal end of the ascending aorta (901), the distal end of the descending thoracic aorta (902), the brachiocephalic trunk in the arch (903), and the left subclavian artery in the arch (904).

[0060] The aorta 9 is radially flipped so that the intima faces outward and the adventitia faces inward, completely flattening the intima surface to facilitate the creation of the initial tear. At the distal end of the left subclavian artery 904 in the arch region, a transverse tear approximately 0.3 cm wide is made in the intima using a scalpel. This opening is then circumferentially enlarged using plastic forceps to construct the initial tear. Subsequently, along the vascular axis, the space between the intima and media is gently dissected from the pre-made tear towards the distal end of the vessel, simulating the false lumen formed by the natural dissection of aortic dissection. The dissection process is controlled to apply even force, ensuring the integrity of the intima flap within the false lumen and preventing secondary irregular tears.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. An experimental platform for simulating a pulsating blood flow circulation loop in a cardiovascular system, characterized in that, include: A circulation loop module is used to provide a fluid channel for circulating flow in an isolated aorta; The pulsation control module is used to simulate the pulsation caused by a heartbeat in the flow of fluid. and The model adaptation module is used to fix the isolated aorta and simulate the original environment of the isolated aorta in a living organism.

2. The experimental platform for simulating the pulsating blood flow circulation loop of a cardiovascular system according to claim 1, characterized in that, The loop module includes: A liquid storage tank is used to store circulating fluids. A piston pump is used to draw fluid from the reservoir and pump it into the fluid channel; A check valve, connected in series in the channel, is used to prevent fluid from flowing backward in the channel; Compliant chambers, connected in series in the channel, are used to buffer fluid pressure fluctuations, mimicking the elastic compliance characteristics of blood vessels; A pressure sensor, connected in series in the channel, is used to measure the pressure of the fluid in the channel; A flow sensor, connected in series in the channel, is used to measure the flow rate of the fluid in the channel; A resistance regulator, connected in series in the channel, is used to adjust the channel's resistance to the fluid, thereby changing the fluid's flow rate and pressure; and Silicone tubing is used to connect the various components of the circulation loop module and the isolated aorta in series to form a closed fluid channel.

3. The experimental platform for simulating the pulsating blood flow circulation loop of a cardiovascular system according to claim 2, characterized in that, The isolated aorta preservation includes four openings: the proximal end of the ascending aorta, the distal end of the descending thoracic aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch; all other openings are closed. The proximal end of the ascending aorta is the fluid inlet; the distal end of the descending aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch are the fluid outlets; The one-way valve, compliant chamber, pressure sensor, flow sensor, and resistance regulator are all in sets of two. The outlet of the piston pump is connected to the proximal end of the ascending aorta through the silicone tube to form an inlet channel; a one-way valve, a compliance chamber, a pressure sensor, a flow sensor and a resistance regulator are connected in series on the inlet channel; The distal end of the descending thoracic aorta is connected to the inlet of the reservoir via the silicone tube to form an outlet channel; The outlet channel is connected in series with a compliant chamber, a pressure sensor, a flow sensor, and a resistance regulator; A one-way valve is connected in series between the outlet of the liquid storage tank and the inlet of the piston pump; The bow head arm is directly connected to the inlet of the liquid storage tank via a silicone tube; The left subclavian artery in the arch is connected to the outlet channel via a silicone tube.

4. The experimental platform for simulating the pulsating blood flow circulation loop of a cardiovascular system according to claim 2, characterized in that, The piston pump includes: a lead screw, a piston, a cylinder, and a ventricular cavity; wherein, The cylinder barrel is a hollow cylinder; The lead screw is connected to the piston at one end and is driven by a motor to make the piston reciprocate in the cylinder. The piston is located in the cylinder, and its side is pressed against the inner wall of the cylinder. Through reciprocating motion, it creates pulsating pressure on the fluid in the cylinder. The ventricular cavity is a hollow shell with three openings. The first opening is connected to one end of the cylinder. The second and third openings serve as the fluid inlet and outlet of the piston pump, respectively. The axes of the second and third openings form a 50-degree angle.

5. The experimental platform for simulating the pulsating blood flow circulation loop of a cardiovascular system according to claim 2, characterized in that, The pulse control module includes: An electric motor is used to provide power to the piston pump; A servo driver, connected to the motor, is used to drive the motor to run according to a set pattern; The PLC controller is connected to the servo driver and is used to generate control commands based on set parameters and output them to the servo driver. Input terminal device, used to receive control parameters input by the user and output the control parameters to the PLC controller; and A power supply is provided to power the various components of the pulse control module.

6. The experimental platform for simulating the pulsating blood flow circulation loop of a cardiovascular system according to claim 1, characterized in that, The model adaptation module includes: A support box is used to hold an isolated aorta; the bottom of the support box is provided with a sponge pad with an arc-shaped groove, which matches the shape of the aorta and provides flexible support for the blood vessel, simulating the support and wrapping of the aorta by the surrounding muscle tissue.

7. A method for testing a pulsating blood flow circulation loop simulating a cardiovascular system, implemented based on the test bench described in any one of claims 1-6, comprising: Step 1: Pre-treat the isolated aorta to form a false lumen, and connect the isolated aorta to the test bench; Step 2: Keep the input blood pressure constant, increase the heart rate in a stepwise manner, and obtain the relationship between heart rate and false lumen blood pressure; keep the input heart rate constant, increase the input blood pressure in a stepwise manner, and obtain the relationship between input blood pressure and false lumen blood pressure. Step 3: Experiments were conducted on blood vessels with initial false lumens of different thicknesses, circumferential lengths, and axial lengths to measure the dissection expansion pressure and obtain the relationship between the expansion pressure and the morphological parameters of the false lumen.

8. The method for testing the pulsating blood flow circulation loop of a simulated cardiovascular system according to claim 7, characterized in that, The pretreatment of the isolated aorta to form a false lumen in the isolated aorta includes: Freshly obtained aortas or aortas that have been cryopreserved and then thawed are selected, retaining the ascending aorta to the descending thoracic aorta segment and removing the fat attached to the outside. Only four entry and exit points for fluid flow were preserved on the aorta: the proximal end of the inferior ascending aorta, the distal end of the descending thoracic aorta, the brachiocephalic trunk in the arch, and the left subclavian artery in the arch. All other branch vessels were closed. The aorta is radially flipped so that the intima faces outward and the adventitia faces inward. At the distal end of the left subclavian artery in the arch, a non-penetrating incision is made in the intima using a scalpel. This incision is then enlarged circumferentially to construct the initial incision. Blunt forceps are then inserted into the medial layer through the initial intimal incision and blunt dissection is performed along the long axis of the aorta to form an artificial false lumen with a set axial length and circumferential range. The aorta will be restored to its original physiological form with the adventitia on the outside.

9. The method for testing the pulsating blood flow circulation loop of a simulated cardiovascular system according to claim 8, characterized in that, The pretreatment of the isolated aorta also includes: A pressure guidewire is inserted from the left subclavian artery in the arch and placed inside the false lumen to measure blood pressure at different locations within the false lumen.

10. The method for testing the pulsating blood flow circulation loop of a simulated cardiovascular system according to claim 8, characterized in that, The pretreatment of the isolated aorta also includes: The thickness of the aortic intima patch, the circumferential length of the false lumen, and the axial length were measured; the measurement methods included: Place a graduated ruler on the same plane as the location to be measured, take a picture vertically with a camera, and obtain the measured value based on the graduations on the ruler as a standard ratio.

Images