JP4587776B2 - Blood flow simulator and flow conversion device - Google Patents

Description

  The present invention relates to a blood flow simulator and a flow conversion device. More specifically, the present invention can reproduce a complicated blood flow state in a predetermined part of a living body, and the performance of an artificial organ and the effect of surgery are almost the same as in a living body. The present invention relates to a blood flow simulator and a flow conversion device that can be examined under conditions.

  The blood pumped out from the human heart passes through the aorta, reaches the various arteries that branch from the aorta to the whole body, joins the corresponding veins to the vena cava, and performs systemic circulation that returns to the heart. Here, an artery that branches from the aorta is a coronary artery stretched around the myocardium, which circulates blood from the base of the aorta to the base of the vena cava and supplies energy and oxygen to the heart. ing. Such blood circulation through the coronary artery is called coronary circulation.

  By the way, when the coronary artery is narrowed or occluded due to arteriosclerosis or the like, myocardial necrosis called myocardial infarction occurs. As a treatment for such stenosis and occlusion of the coronary artery, catheter therapy and coronary artery bypass surgery are known in addition to drug therapy. Catheter therapy expands the blood flow path that is narrowed by inflating the balloon in the stenotic coronary artery, and maintains the expanded state of the blood flow path by placing a vascular dilator called a stent at the expanded site. Is. On the other hand, the coronary artery bypass operation is an operation for newly securing another path of the coronary artery so as to bypass the constricted site, and it is necessary to cut an existing blood vessel or suture (anastomize) blood vessels.

  It is essential to evaluate the performance of the stent for coronary artery used for the catheter therapy in order to ensure compatibility with the human body. On the other hand, in coronary artery bypass surgery, there are various methods for anastomosis of blood vessels, and which method is ideal has not yet been elucidated, and the durability of these methods over time has been demonstrated, making the ideal method objective. Supporting these data is essential for the development of medicine.

  Therefore, for verification of stent performance and vascular anastomosis, it is common to conduct experiments using animals that have coronary flow similar to humans. However, there are not a few restrictions on ethical aspects such as animal welfare, and it is difficult to obtain empirical data considering individual differences in various states such as blood flow and blood pressure.

For this reason, a device that can create a flow state simulating the coronary artery flow of the human body and simulate the stent and anastomosis in the flow is required. Here, conventionally, a pump capable of generating a pulsating flow similar to that of a human body is known (see Patent Document 1 and Patent Document 2).
JP-A-4-357960 JP 59-108559 A

  However, each of the pumps simulates a heart having a blood pump function, and makes it possible to reproduce the flow immediately after being pumped from the heart, that is, the aortic flow. Therefore, there is an inconvenience that simply using the pump cannot reproduce a coronary artery flow that is significantly different from the aortic flow. That is, the flow in the aorta immediately after being pulsated from the heart has a waveform as shown in FIG. 3, and when viewed in a range of one cycle, the flow rate increases when the heart contracts, and the heart dilates. At time D, it becomes a single mountain shape with almost no flow rate. However, the flow in the coronary artery has a waveform as shown in FIG. 4, and when viewed in the range of one cycle, there is a slight flow rate at the contraction time S, and the flow rate at the expansion time D is higher than that at the contraction time S. It becomes a shape that there are two mountains that increase. In other words, the coronary artery flow is in a state completely different from the aortic flow because various elements such as contraction and relaxation of the myocardium around which the coronary artery flow is stretched are intricately acting. Therefore, when evaluating the performance of the stent with respect to the flow of the coronary artery and the evaluation of the anastomosis method, even if a simple closed loop circuit including the pump is used, the stent or the like cannot be exposed to the flow in the coronary artery. Is impossible. In general, a simple circulation circuit using the pump has a disadvantage that it cannot accurately evaluate an artificial organ, a medical device, or a surgical method applied in an artery branched from an aorta.

  The present invention has been devised by paying attention to such inconveniences, and the object of the present invention is to accurately reproduce the flow state in other blood vessels different from the aorta, and to be applied in the flow state. An object of the present invention is to provide a blood flow simulator and a flow conversion device that can contribute to accurate evaluation of artificial organs, medical devices, surgical methods, and the like.

(1) In order to achieve the above object, the present invention provides a blood flow simulator for applying a flow simulating blood flow to a predetermined fluid.
A pulsating flow generating device that generates a pulsating flow for the fluid, and converting the pulsating flow into a desired flow state by applying suction to the pulsating flow generated by the pulsating flow generating device. And a flow conversion device
The flow conversion device has a configuration in which an installation unit capable of installing a predetermined test object in the converted fluid flow is provided.

(2) In a blood flow simulator for applying a flow simulating blood flow to a predetermined fluid,
A pulsatile flow generating device that generates a pulsatile flow simulating an aortic flow with respect to the fluid, and applying a suction force to the pulsatile flow generated by the pulsatile flow generating device, thereby converting the pulsatile flow into a coronary artery A flow conversion device for converting into a flow state simulating a flow,
The flow conversion device can also be configured such that an installation portion is provided in which a predetermined test object can be installed in a fluid flow simulating a coronary artery flow.

  (3) Furthermore, it is preferable that the flow conversion device adopts a configuration in which a flow rate and a pressure of the fluid supplied to the installation unit are independently adjustable.

(4) In a blood flow simulator for applying a flow simulating blood flow to a predetermined fluid,
A body circulation device that simulates body circulation of a living body and circulates the fluid; and a coronary circulation device that branches from the body circulation device and circulates the fluid by simulating the body coronary circulation;
The coronary circulation device includes an inlet-side flow channel branched from the aortic flow portion of the systemic circulation device, an outlet-side flow channel connected to the vena cava portion of the systemic circulation device, an inlet-side flow channel, and an outlet-side flow channel, respectively. A connected closed-loop loop channel, first and second branch channels branching from the loop channel, an actuator disposed between ends of the branch channels, and the loop channel And a check valve provided in
The inlet-side flow path is provided with an installation part capable of installing a predetermined test object,
The actuator includes first and second syringes having discharge ports connected to the first and second branch flow paths, and a drive device that increases and decreases the volume in the syringes simultaneously in a mutually contradictory state,
The check valve allows the fluid in the body circulation device to flow in from the inlet side flow channel and flow out from the outlet side flow channel to the body circulation device regardless of whether the volume in each syringe changes. Arranged as
A configuration in which a flow state simulating coronary artery flow is imparted to the fluid flowing through the installation portion by increasing or decreasing the volume in each syringe almost in synchronization with the pulsatile flow generated by the systemic circulation device. Can also be taken.

  (5) Furthermore, it is preferable to employ a configuration in which pressure adjusting means for adjusting the pressure of the fluid flowing through the installation portion is provided.

(6) Further, the present invention is a flow conversion device that generates a flow state simulating a coronary flow using a pulsating flow of a fluid simulating an aortic flow,
Connected to the inlet-side channel into which the pulsating flow is introduced, the outlet-side channel that flows out the fluid after the generation of the flow state simulating the coronary artery flow, and the inlet-side channel and the outlet-side channel, respectively. A closed loop loop flow path, first and second branch flow paths branched from the loop flow path, an actuator disposed between the ends of the branch flow paths, and the loop flow path. A check valve,
The inlet-side flow path is provided with an installation portion on which a predetermined test object can be set, and the actuator has first and second syringes having discharge ports connected to the first and second branch flow paths. And a drive device that increases or decreases the volume in the syringe at the same time,
The check valve is arranged so that the fluid flows in from the inlet-side flow channel and flows out of the outlet-side flow channel, regardless of whether the volume in each syringe changes or not.
By adopting a configuration in which the volume in each syringe is increased or decreased substantially in synchronization with the pulsatile flow, a flow state simulating the coronary flow is imparted to the fluid flowing through the installation portion.

  According to the configurations of (1) and (2) above, various evaluations are performed by exposing the test object to a flow simulating an arbitrary arterial flow or venous flow, such as a coronary flow of a living body, with a flow conversion device. be able to. Thereby, for example, a change in the properties of the stent and biocompatibility when used in a coronary artery can be examined by using a fluid simulating blood. In addition, when anastomosing blood vessels, it is possible to acquire flow data over time by passing fluids simulating coronary flow through channels using various anastomosis methods. It is also possible to objectively evaluate the anastomosis method. Furthermore, it is possible to objectively evaluate the coronary artery anastomosis ability by exposing the simulated blood vessel anastomosed by a doctor, a robot, or the like to a flow simulating the coronary artery flow.

  By configuring as in the above (3), it is possible to evaluate the test object assuming various individuals with different blood pressure states and blood flow states, and the evaluation data of the test object according to the patient's pathological condition Can be acquired.

  According to the configurations of (4) and (6), the pulsatile flow can be converted into the coronary artery flow using the suction force due to the increase in the volume in the syringe, Various evaluations can be made by exposing the test object inside. In addition, when the volume in the syringe is increased or decreased, by changing the amount of change, the amount of fluid discharged from the syringe can be changed, and the flow rate of the fluid flowing in the apparatus can be controlled.

  With the configuration of (5), the flow rate and pressure of the fluid flowing in the apparatus can be arbitrarily and independently adjusted, and the test object is assumed assuming various individuals with different blood pressure states and blood flow states. The evaluation can be performed, and the evaluation data of the test object according to the patient's pathological condition can be acquired.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of a blood flow simulator according to the present embodiment. In this figure, a blood flow simulator 10 has a circulation circuit configuration that applies a flow simulating the blood flow of a human body to a predetermined fluid, and a body circulation device 11 that circulates a fluid by simulating body circulation, It is constituted by a coronary circulation device 12 that branches from the body circulation device 11 and circulates fluid by simulating coronary circulation. Note that the fluid to be applied is not particularly limited, and examples thereof include blood, a liquid imitating blood, a physiological saline, water, and a liquid such as a predetermined treatment liquid.

  The body circulation device 11 functions as a pulsatile flow generating device that generates a pulsatile flow with respect to a fluid. This systemic circulator 11 has a pulsation pump 14 that simulates the pumping of blood from the heart and an aorta tube that simulates the human aorta and is connected to the outflow part 14A of the pulsation pump 14. 16, a vena cava tube 17 that simulates the vena cava of the human body and is connected to the inflow portion 14B of the pulsation pump 14, a first tank 19 that is connected to the aorta tube 16, and a vena cava tube 17 The second tank 20, the peripheral tube 21 communicating the first and second tanks 19, 20, and the resistance provided to the fluid in the peripheral tube 21 provided in the middle of the peripheral tube 21. An applicator 22 is provided.

  The pulsating pump 14 includes a diaphragm 26 that partitions a main space 24 in which the fluid is stored and a sub space 25 in which air is stored. The diaphragm 26 is set to be displaced by the pressure of the air supplied to the subspace 25, change the volume of the main space 24 by the displacement, and discharge and suck fluid into the space 24. In addition, the pressure of the fluid pumped out from the pulsation pump 14 can be changed by adjusting the air pressure for displacing the diaphragm 26 and the resistance applying tool 22. The fluid discharged from the pulsating pump 14 becomes a pulsating flow such as a blood flow from the heart of a human body.

  The pulsating pump 14 is not limited to the structure described above, and may be anything having a structure capable of imparting a pulsating flow to a fluid like the heart.

  The first tank 19 is filled with the fluid and air, and is provided to simulate a blood flow attenuation state caused by vascular elasticity when blood passes through the aorta. That is, the amount of liquid and the air pressure in the tank 19 are adjusted so that the fluid flowing in the erasing tube 21 corresponds to the flow state after passing through the aorta.

  The second tank 20 has the fluid and air sealed therein, and is provided for simulating a blood flow state after blood passes through a vein. That is, the amount of liquid and the air pressure in the tank 20 are adjusted so that the fluid flowing through the vena cava tube 17 is in a flow state immediately after joining the various veins in the body to the vena cava.

  The resistance applying tool 22 is not particularly limited, but is a pinch-like tool that can tighten the erasing tube 21 from the outer peripheral surface side, and simulates erasing resistance.

  Such a body circulation device 11 constitutes a circulation circuit in which the fluid pumped from the pulsation pump 14 returns to the pulsation pump 14 through the aortic tube 16, the peripheral tube 21, and the vena cava tube 17. A check valve 28 is provided in the aortic tube 16 and the vena cava tube 17 to maintain the unidirectional circulation state and prevent the back flow of fluid during operation of the pulsation pump 14. .

  The coronary circulation device 12 functions as a flow conversion device that converts the pulsatile flow into a desired flow state by applying a suction force to the pulsatile flow generated by the body circulation device 11. The coronary circulation device 12 includes an inlet-side flow path 30 made of a tube branched from the aortic tube 16, an outlet-side flow path 31 made of a tube connected to the second tank 20, and the flow paths 30, 31. And a coronary circulation simulator 33 that simulates the flow state in the inlet-side channel 30 to the flow state in the coronary artery of the human body.

  An installation part 35 in which a predetermined test object T is installed is provided in the middle of the inlet-side flow path 30. The test object T of the present example is a bifurcated flow channel in which two tubes are anastomosed so that various evaluations regarding anastomoses between blood vessels during coronary artery bypass surgery can be performed. This channel is in a state where two of the three ends are connected in the middle of the inlet-side channel 30 and the remaining one end is closed. In addition, a tube or the like in which a medical instrument such as a stent, an artificial organ, or the like is accommodated can be disposed as the test object T in the installation portion 35.

  A pressure adjusting means 37 for adjusting the pressure of the fluid flowing in the coronary circulation device 12 is provided in the middle of the outlet side flow path 31. The pressure adjusting means 37 is not particularly limited, and is configured by a pinch-like resistance applying tool that provides resistance to the fluid passing through the flow path 31 by changing the inner diameter of the outlet flow path 31. ing.

  As shown in FIG. 2, the coronary circulation simulator 33 includes a loop flow path 39 configured by a closed loop tube connected to the inlet-side flow path 30 and the outlet-side flow path 31, and the loop flow path. 39, first and second branch flow paths 42 and 43 each constituted by a tube branching from 39, and an actuator 44 disposed between the ends of the branch flow paths 42 and 43.

  The loop channel 39 is connected to the inlet channel 30, the outlet channel 31, and the first and second branch channels 42, 43 at substantially equal intervals. Specifically, the inlet-side channel 30 and the outlet-side channel 31 are connected at the upper and lower positions in FIG. Further, the first and second branch flow paths 42 and 43 are connected at the left and right positions in FIG.

  In addition, first to fourth check valves 46 to 49 are provided at substantially equal intervals at four points in the middle of the loop flow path 39, and these check valves 46 to 49 are indicated by solid lines in FIG. They are arranged in directions that allow the flow in the direction of the arrows.

That is, the first check valve 46 is disposed between the connection portion of the inlet side flow passage 30 and the connection portion of the first branch flow passage 42 on the left side in FIG. Only flow is allowed.
The second check valve 47 is disposed between the connection portion of the first branch flow path 42 and the connection portion of the outlet side flow path 31 so as to allow only a counterclockwise flow in FIG. It has become.
The third check valve 48 is disposed between the connection portion of the outlet side flow passage 31 and the connection portion of the second branch flow passage 43 on the right side in FIG. 3, and allows only the clockwise flow in FIG. It comes to allow.
The fourth check valve 49 is disposed between the connection portion of the second branch flow path 43 and the connection portion of the inlet-side flow path 30, and allows only a clockwise flow in FIG. ing.

  The actuator 44 has the first and second syringes 53 and 54 having the discharge ports E connected to the first and second branch flow paths 42 and 43, and the volumes in the syringes 53 and 54 conflicted simultaneously. A driving device 56 that increases and decreases in a state and a support 57 that supports the first and second syringes 53 and 54 are provided.

  The first and second syringes 53 and 54 include piston plates 53A and 54A that partition an internal space in which fluid is accommodated, and rods 53B and 54B connected to the piston plates 53A and 54A. These rods 53B and 54B are arranged in a substantially straight line in opposite directions.

  The driving device 56 is connected to the connecting member 58 that integrally connects the opposite ends of the rods 53B and 54B, the connecting rod 59 that is connected to the connecting member 58, and the connecting rod 59. And a motor 61 that moves 58 in a predetermined direction. The driving device 56 can simultaneously move the rods 53B and 54B of the syringes 53 and 54 arranged in a straight line in the same direction on the straight line by driving the motor 61. That is, when the motor 61 is driven with respect to the syringes 53 and 54 arranged back to back in the left-right direction in FIG. 2, the connecting member 58 moves in the left-right direction. The volume of the space will increase or decrease in a contradictory state. That is, when the connecting member 58 moves to the left in FIG. 2, the volume in the first syringe 53 on the left side in the same figure decreases, and the first syringe 53 moves from the first branch channel 42 to the loop channel 39. As the internal fluid is discharged, the volume in the second syringe 54 on the right side of the figure increases, and the fluid is sucked from the loop flow path 39 to the second branch flow path 43. On the other hand, when the connection member 59 moves to the right in FIG. 2, the operation is the reverse of the above, and fluid is discharged from the second branch flow path 43 to the loop flow path 39 and from the loop flow path 39 to the first flow path. The fluid is sucked into the branch flow path 42. Here, the drive timing of the motor 61 operates at a timing substantially synchronized with the pulsation pump 14 (see FIG. 1). Specifically, the connection member 58 is set to move in a predetermined movable range only in one direction during one cycle of the pulsation pump 14 that passes through the systole and the diastole. Therefore, the connection member 58 reciprocates once in the movable range in two cycles of the pulsating pump 14. Note that the movable range can be arbitrarily changed, whereby the amount of liquid sucked into the syringes 53 and 54 is changed, and the flow rate of the fluid flowing through the coronary circulation device 12 can be adjusted.

  In place of the motor 61, various actuators such as a cylinder having the same operation as described above can be applied.

  Next, the operation of the blood flow simulator 10 will be described.

  In the body circulation device 11, a fluid circulation state that simulates the body circulation state of the human body is generated by the operation of the pulsation pump 14. At this time, in the aortic tube 16, a flow rate waveform approximate to the biological aortic flow shown in FIG. 3 is obtained. At the same time, in the coronary circulation device 12, the motor 61 is driven almost in synchronization with the pulsating flow from the pulsating pump 14, and fluid is sucked into the coronary circulation device 12 from the aortic tube 16 by the action of the syringes 53 and 54. It is.

  At this time, the driving of the motor 61 causes the connecting member 58 to reciprocate in the left-right direction in FIG. 2, but the volume in each syringe 53, 54 increases or decreases regardless of whether the connecting member 58 moves to the left or right. Regardless of the change, the fluid of the body circulation device 11 flows into the coronary circulation simulator 33 from the inlet-side flow path 30 using the suction force of one of the syringes 53 and 54, and from the outlet-side flow path 31. It will be discharged to the body circulation device 11. That is, when the connecting member 58 moves to the left in FIG. 2, the fluid flow is allowed in the coronary circulation simulator 33 in the direction indicated by the dashed line in FIG. Thus, the fluid from the inlet-side channel 30 flows into the outlet-side channel 31. On the other hand, when the connecting member moves to the right in FIG. 2, the fluid flow is allowed in the coronary circulation simulator 33 along the path indicated by the two-dot chain line in FIG. Thus, the fluid from the inlet-side channel 30 flows into the outlet-side channel 31. As a result, in the inlet-side channel 30, a flow rate waveform approximating the biological coronary artery flow shown in FIG. 4 is obtained. That is, when the driving of the motor 61 is stopped in a state where the fluid in the body circulation device 11 is circulating, the flow rate waveform like the noise shown in FIG. . At this time, a small amount of fluid flows from the inlet-side flow path 30 to the coronary circulation device 12 due to the pulsation of the pulsation pump 14, but is shown in FIG. The flow rate waveform collapses and becomes the flow rate waveform of FIG. However, as described above, when the pump 61 is driven so as to be synchronized with the operation of the pulsating pump 14, any one of the syringes 53 and 54 is used during the period from the systole to the diastole of the pulsating pump 14. The fluid suction is continuously performed. Therefore, the suction force of the syringes 53 and 54 acts on the flow rate waveform of FIG. 3 with a predetermined time delay, and a flow rate waveform that approximates the flow state of the human coronary artery shown in FIG. 4 can be obtained. That is, the flow waveform of the fluid passing through the installation part 35 appears as a small mountain corresponding to the systole S of the pulsatile flow and a large mountain corresponding to the diastole D, like the coronary flow of the living body. A valley portion peculiar to coronary artery flow is formed between the two peaks.

  Therefore, according to such an embodiment, a fluid flow simulating the coronary artery flow can be imparted to the installation portion 35, and animal experiments such as evaluation of coronary artery anastomosis techniques, evaluation of coronary stent performance, etc. The effect of being able to carry out correctly irrespective of it is acquired.

  Further, by adjusting the moving position and moving amount of the connecting member 58, the discharge amount of the fluid from the syringes 53 and 54 can be changed, and the flow rate circulating in the coronary circulation device 12 can be controlled. With such a configuration, the flow rate control in the coronary circulation device 12 can be performed independently of the fluid pressure control adjusted by the pressure adjusting means 37. For example, high blood pressure / low blood flow rate, low blood pressure / high blood pressure, etc. There is also an effect that various patient conditions such as flow rate can be reproduced.

  In the above-described embodiment, the pulsating flow generation device and the flow conversion device are in a circulating state. However, the present invention is not limited to this, and if the fluid flowing through the test object T becomes a flow simulating a coronary artery flow, the circulation is performed. It is not necessary to have a circuit configuration.

  Moreover, although the blood flow simulator 10 simulates the coronary artery flow state of the human body, the setting of the pulsation pump 14 or the like may be changed to simulate the coronary artery flow state of another animal.

  Furthermore, by changing the operation timing of the actuator 44 or the like, it is possible to change the blood flow state of another artery or vein to the fluid flowing through the installation portion 35.

  In addition, the configuration of each part of the apparatus in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same operation is achieved.

The schematic block diagram of the blood-flow simulator which concerns on a present Example. The principal part enlarged view of FIG. A flow waveform representing the aortic flow in the human body. A flow waveform representing the coronary flow of the human body. Flow rate waveform near the installation area when the systemic circulation device is activated and the coronary circulation device is stopped.

Explanation of symbols

10 blood flow simulator 11 systemic circulation device (pulsatile flow generator)
12 coronary circulation device (flow converter)
30 Inlet side channel 31 Outlet side channel 35 Installation portion 37 Pressure adjusting means 39 Loop channel 42 First branch channel 43 Second branch channel 44 Actuator 46 First check valve 47 Second check Valve 48 Third check valve 49 Fourth check valve 53 First syringe 54 Second syringe 56 Drive device T Test object E Discharge port

Claims (3)

In a blood flow simulator that applies a flow simulating blood flow to a predetermined fluid,
A body circulation device that simulates body circulation of a living body and circulates the fluid; and a coronary circulation device that branches from the body circulation device and circulates the fluid by simulating the body circulation
The coronary circulation device, an inlet-side flow path branch know aortic portion of the body circulation device, the outlet passage leading to the vena cava part of the body the circulation device, the inlet passage and the outlet passage Closed loop loop flow paths connected to each other, first and second branch flow paths branched from the loop flow paths, actuators arranged between ends of the branch flow paths, and the loop flow paths And a check valve provided in the interior,
The inlet-side flow path is provided with an installation part capable of installing a predetermined test object,
The actuator includes first and second syringes having discharge ports connected to the first and second branch flow paths, and a drive device that increases and decreases the volume in the syringes simultaneously in a mutually contradictory state,
The check valve allows the fluid in the body circulation device to flow in from the inlet side flow channel and flow out from the outlet side flow channel to the body circulation device regardless of whether the volume in each syringe changes. Arranged as
A flow state simulating a coronary artery flow is imparted to the fluid flowing through the installation portion by increasing or decreasing the volume in each syringe almost in synchronization with the pulsatile flow generated by the systemic circulation device. A blood flow simulator. Blood flow simulator of claim 1, wherein the pressure adjusting means for adjusting the pressure of the fluid flowing through the installation portion. A flow conversion device that generates a flow state simulating a coronary flow using a pulsating flow of a fluid simulating an aortic flow,
Connected to the inlet-side channel into which the pulsating flow is introduced, the outlet-side channel that flows out the fluid after the generation of the flow state simulating the coronary artery flow, and the inlet-side channel and the outlet-side channel, respectively. A closed loop loop flow path, first and second branch flow paths branched from the loop flow path, an actuator disposed between the ends of the branch flow paths, and the loop flow path. A check valve,
The inlet-side flow path is provided with an installation part capable of installing a predetermined test object ,
The actuator includes first and second syringes having discharge ports connected to the first and second branch flow paths, and a drive device that increases and decreases the volume in the syringes simultaneously in a mutually contradictory state,
The check valve is arranged so that the fluid flows in from the inlet-side flow channel and flows out of the outlet-side flow channel, regardless of whether the volume in each syringe changes or not.
A flow conversion device characterized in that a flow state simulating coronary artery flow is imparted to the fluid flowing through the installation portion by increasing or decreasing the volume in each syringe substantially in synchronization with the pulsatile flow.

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