JP2017140334A - Durability test apparatus and durability test method of medical test object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durability test apparatus installing a test object in a pulsatile flow simulating a blood flow state of a human body such as a coronary circulation environment, and applying a bending load or the like to an installation part of the test object under a discretionary condition synchronized with a pressure waveform and/or a flow waveform of the blood flow.SOLUTION: A durability test apparatus 10 according to the present invention includes: a flow passage 11 in which a test fluid flows; an installation part 12 that is provided halfway through the flow passage 11, at which a test object T is installed, and that is configured to be bendingly deformable; flow generation means 14 making the test fluid circulating in the flow passage 11 a pulsatile flow; flow state detection means 15 for detecting a pressure and/or a flow rate of the test fluid; actuating means 17 applying an external load to the installation part 12 and actuating to bendingly deform it; and control means 18 controlling the actuation of the actuating means 17 according to the state of the pressure and/or the flow rate detected by the flow state detection means 15.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a durability test apparatus and a durability test method for stents and other medical devices used for coronary arteries, and more specifically, the durability test can be artificially performed by simulating a use environment in a human body. The present invention relates to a durability test apparatus and a durability test method for a medical test object.

  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, the 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.

  As stents placed in coronary arteries, in addition to conventional metal stents, recently, bioabsorbable stents that have been absorbed into the body and disappeared within a few months to years after placement of blood vessels have appeared. Clinical trials are being conducted. According to the International Organization for Standardization (ISO) standards, four items of mechanical evaluation, repeated fatigue endurance, physical properties of degradation, and material composition evaluation have been made for the cardiovascular absorbable implant including the bioabsorbable stent. Although there is a guideline that non-clinical evaluation should be performed in vitro, specific test methods for each evaluation item have not yet been established, and establishment of such specific test methods is widely requested.

  By the way, Patent Document 1 discloses a performance evaluation simulator for coronary stents. The stent performance evaluation simulator has a circuit configuration that simulates coronary circulation, and has a liquid flow path, a pump that applies a pulsating flow to the liquid circulating in the liquid flow path, and a branch in the middle of the fluid flow path And a flexible tube provided in the middle of the branch pipeline. A stent to be evaluated is placed in the flexible tube, and the stent is exposed to a liquid to which pulsatile flow is applied. Therefore, with this simulator, it is possible to examine the durability of the stent under conditions close to blood pulsation conditions during actual use.

  Patent Document 2 discloses a blood vessel motion simulator that can simulate the behavior of blood vessels caused by biomechanical loads due to body movements and the like, and perform a stent durability test in consideration of the behaviors. Yes. In this blood vessel operation simulator, a stent is placed in a simulated blood vessel filled with a liquid, and then the simulated blood vessel is bent and deformed by a driving means such as a motor.

Japanese Patent No. 4166905 Japanese Patent No. 4968882

  According to the findings based on the study by the present inventors, in order to accurately perform a non-clinical durability test on a bioabsorbable stent placed in the coronary artery, the stent is in a flow state corresponding to the coronary circulation environment. In addition to confirming changes in the physical properties of the stent such as degradation over time, the entire blood vessel in which the stent is placed is subject to movement events such as bending, stretching, and twisting due to the pulsatile state of the coronary artery flow. It is necessary to consider. Here, the state of each movement of the blood vessels during the diastole or systole of the heart differs depending on the individual patient and the indwelling part of the stent, so the coronary flow state and the movement are synchronized according to each assumed case. It is necessary to let For example, there may be a case where the blood vessel bends gently during the diastole of the heart while the blood vessel bends greatly during the systole of the heart and vice versa. In some cases, the blood vessel bends to the maximum when the blood pressure value is maximum.

  However, in the stent performance evaluation simulator of Patent Document 1, there is no structure for forcibly deforming the flexible tube itself in which the stent is placed, such as bending, expansion, contraction, and twisting, and the pulsation of coronary flow It is impossible to conduct a durability test that causes the flexible tube to move such as bending, expansion / contraction, and twisting according to the state. In addition, the blood vessel motion simulator of Patent Document 2 performs a durability test in consideration of the behavior of blood vessels caused by biomechanical loads due to body movements, such as when a stent is placed in a superficial femoral vein or the like. The external load such as bending, twisting, and expansion / contraction to the simulated blood vessel corresponding to the fluid pressure and flow rate when the stent is placed in the coronary artery cannot be arbitrarily changed.

  The present invention has been devised to solve such problems, and its purpose is to install a test object in a pulsatile flow that simulates a blood flow state of a human body such as a coronary circulation environment. A medical test object capable of applying an external load that causes bending, twisting, expansion and contraction, etc. to the installation part of the test object under arbitrary conditions synchronized with the blood pressure waveform and / or the flow waveform An endurance test apparatus and a durability test method are provided.

  In order to achieve the above object, the present invention mainly comprises a fluid circuit that circulates a predetermined test fluid, a medical test object is placed in the middle of the fluid circuit, and human blood is placed in the test fluid. An apparatus for performing a durability test of the medical test object by providing a flow simulating a flow state, the flow path for the test fluid flowing, and the test object provided in the middle of the flow path An installation part configured to allow bending deformation, torsional deformation, and / or expansion / contraction deformation, and a flow generation unit that pulsates the test fluid circulating in the flow path. A flow state detecting means for detecting the pressure and / or flow rate of the test fluid; an operating means that operates to apply an external load to the installation portion to cause bending deformation, torsion deformation, and / or expansion / contraction deformation; Detect with flow state detection means It has been in accordance with the state of the pressure and / or flow, and control means for controlling the operation of said operation means, and employs a configuration that.

  According to the present invention, a test object is placed in a flow state of a test fluid that simulates a pulsatile flow in an actual coronary circulation environment, and then synchronized with a periodic change in pressure and / or flow rate of the test fluid. Thus, a bending load, a torsion load, and / or an expansion / contraction load can be applied to the installation portion of the test object at any desired timing. Therefore, the durability test of a test object such as a bioabsorbable stent placed in the coronary artery can be performed in the same situation while assuming various cases where the test object is placed in an actual human body. For absorptive stents and the like, durability evaluation can be easily and accurately performed using a non-clinical artificial test apparatus.

The conceptual diagram showing the structure of the durability test apparatus which concerns on this embodiment. (A), (B) is a conceptual diagram for demonstrating the state in which the bending load is acting on the installation part by the operation means.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing the configuration of a durability test apparatus such as a medical device according to this embodiment. In this figure, the durability test apparatus 10 is constituted by a fluid circuit that circulates a predetermined test fluid, and a test object T such as a medical device or a medical material is installed in the middle of the fluid circuit to perform the test. This is a device for non-clinically testing the durability of the test object T by giving the fluid a flow that simulates the blood flow state of the human body and simulating the same state as when used on the human body. . Here, examples of the test object T include various stents such as a bioabsorbable stent. Examples of the test fluid include liquids such as phosphate buffered saline (PBS).

  The durability test apparatus 10 includes an annular flow path 11 configured so that a test fluid circulates in one direction in a non-air contact state, and a test object T provided in the middle of the flow path 11. In addition, the installation part 12 configured to be bent and deformable, the flow generating means 14 for bringing the test fluid circulating in the flow path 11 into a pulsating state, and the test fluid on the inlet side of the installation part 12 The flow state detection means 15 for detecting the pressure and / or flow rate state of the gas, the operating means 17 that operates to apply an external force load to the installation portion 12 to bend and deform, and the pressure and the pressure detected by the flow state detection means 15 And / or a control unit 18 for controlling the operation of the operation unit 17 in accordance with the flow rate state.

  Although the flow path 11 is not particularly limited, the flow path 11 is made of an elastic tube made of resin or the like, and the test fluid is rotated clockwise in FIG. It is configured to circulate only in the direction.

  The installation portion 12 is composed of an elastic tube that can be deformed by an external force of a predetermined size or more, and is provided detachably with respect to the flow path 11 and flows while holding and holding the test object T. An internal space communicating with the path 11 is provided. In the present embodiment, the bioresorbable stent is inflated as the test object T in the installation portion 12, and the test object T holds the test fluid in a state where pulsatile flow is applied. It will pass through the internal space of the installation part 12 made.

  The flow generation means 14 includes a pump 22 that serves as power for flowing the test fluid in the flow path 11, a compliance tube 23 disposed between the installation unit 12 and the upstream side of the pump 22, and the installation unit 12. And a capacity increasing tube 24 arranged between the pump 22 and the downstream side of the pump 22, and a resistance applying unit 25 arranged between the compliance tube 23 and the downstream side of the installation unit 12.

  In the present embodiment, as the pump 22, a roller 26 rotates along the flow path 11, and the roller 26 sucks and discharges the test fluid by handling the flow path 11 while periodically crushing the flow path 11. A roller pump is used. In the present invention, other pumps can be substituted as long as the test fluid flowing in the flow path 11 can be in a pulsatile state. Further, the backflow prevention valves 20 are arranged on the inlet side and the outlet side of the pump 22 respectively.

  The compliance tube 23 is formed of an elastic tube that elastically deforms so that its inner diameter can be expanded and contracted according to a change in pressure of the test fluid that passes through the compliance tube 23, and has a larger inner diameter than the tube constituting the flow path 11. Yes. In addition, although it does not specifically limit, the thing made from silicone is used for the compliance tube 23 of this embodiment. The compliance tube 23 has the following pressure adjustment action. That is, at the timing when the pressure of the flow path 11 by the roller 26 of the pump 22 is released, a vacuum suction force (negative pressure) is generated on the pump 22 side. By contracting, the pressure drop of the test fluid due to the generation of the vacuum suction force is suppressed, and the pressure fluctuation range of the test fluid simulating the blood pressure range in the coronary artery flow of the human body can be reproduced.

  The capacity increasing tube 24 has an inner diameter larger than that of the tube constituting the flow path 11, and functions as a reservoir for temporarily storing the test fluid flowing in the flow path 11.

  The resistance applying portion is constituted by 25, a clamp or the like for applying a restricting resistance to the flow path 11. However, the present invention is not limited to this, and various kinds of valves and the like can be used as long as the same action is achieved. Equipment can be employed alternatively.

  In the flow generating means 14 having the above configuration, the length and inner diameter of the compliance tube 23 and the capacity increasing tube 24 are set so that the actual coronary circulation environment in which the test object T is placed is simulated. Thus, a predetermined flow resistance is added to the flow path 11 by the resistance applying unit 25 and the drive control of the pump 22 is performed. The flow generation unit 14 is not limited to the above-described configuration as long as a pulsating flow of the test fluid can be generated in the flow path 11, and various configurations can be adopted.

  The flow state detection means 15 includes a pressure gauge 27 that measures the inlet pressure of the test fluid on the inlet side of the installation unit 12 and a flow meter 28 that measures the flow rate of the test fluid on the inlet side of the installation unit 12. .

  The operating means 17 is attached to both ends of the installation portion 12 in the extending direction, and is attached to the holding portions 30 and 31 disposed so as to be relatively close to each other and one holding portion 30 located on the left side in FIG. And a driving device 33 serving as power for moving the one holding portion 30 toward and away from the other holding portion 31. In the present embodiment, a voice coil motor is used as the driving device 33, but other actuators can be substituted as long as the same action is achieved. Further, as shown in FIG. 2, by driving the driving device 33, the one holding portion 30 is moved with respect to the other holding portion 31, and the holding portions 30 and 31 are repeatedly separated and approached. . Due to the periodic separating and approaching operation of the holding units 30 and 31, bending loads having different sizes periodically act on the installation unit 12 supported at both ends by the holding units 30 and 31. In this case, a bending motion that repeats bending and restoration (extension) from a straight state is performed.

  In the control means 18, the bending motion of the installation portion 12 is based on periodic changes in the pressure and flow rate of the test fluid on the inlet side of the installation portion 12 based on the measurement value by the pressure gauge 27 and / or the flow meter 28. The drive of the drive device 33 is controlled so as to synchronize. That is, the control means 18 can control a plurality of patterns, and can select a desired control pattern in the durability test based on an input command from an input device (not shown). Specifically, for example, it is possible to select a trigger function for driving and controlling the drive device 33 so as to start the bending motion of the installation unit 12 at the timing when the flow rate or pressure of the test fluid reaches a predetermined value. In addition, a delay function for performing phase adjustment when the installation portion 12 is periodically bent and deformed so that the timing at which the pressure or flow rate of the test fluid is maximized and the timing at which the installation portion 12 is bent to the maximum is matched. You can also choose.

  According to the above embodiment, since the coronary artery bending motion corresponding to the diastolic and systolic phases of the heart can be simulated and the test can be performed in a situation near clinical time considering the bending motion, the indwelling in the coronary artery This makes it possible to accurately evaluate the durability of a bioabsorbable stent or the like. In addition, with regard to the synchronization of the pulsating state and bending motion of the test fluid flowing in the installation unit 12, it is possible to perform control according to the assumed use situation by any setting, and the indwelling site or use of a bioabsorbable stent or the like Durability tests that take into account detailed assumptions due to individual differences among individuals.

  The operating means 17 may be configured to apply an external load to the installation portion 12 so as to cause torsional deformation and / or expansion / contraction deformation in addition to or along with the bending deformation. Even in this configuration, as in the above-described embodiment, the control means 18 periodically changes the pressure and flow rate of the test fluid on the inlet side of the installation unit 12 based on the measurement values obtained by the pressure gauge 27 and the flow meter 28. Based on this, the drive of the drive device 33 is controlled so as to synchronize the bending motion, twisting motion and / or telescopic motion of the installation part 12.

  Further, the operation means 17 is not limited to the above-described configuration, and various structures and configurations can be adopted as long as the same action is achieved.

  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.

DESCRIPTION OF SYMBOLS 10 Endurance test apparatus 11 Flow path 12 Installation part 14 Flow production | generation means 15 Flow state detection means 17 Operation | movement means 18 Control means T Test object

Claims (5)

The medical test is configured by a fluid circuit that circulates a predetermined test fluid, a medical test object is installed in the middle of the fluid circuit, and a flow that simulates a blood flow state of a human body is applied to the test fluid. An apparatus for performing a durability test on an object,
A flow path through which the test fluid flows, an installation portion configured to be bent, torsionally deformed and / or stretchable and deformed while the test object is installed in the middle of the flow path; A flow generating means for bringing the test fluid circulating in the flow path into a pulsating state; a flow state detecting means for detecting the pressure and / or flow rate of the test fluid; and an external load applied to the installation portion. In addition, control means for controlling the operation of the operation means in accordance with the state of the pressure and / or flow rate detected by the flow state detection means, and the operation means that operates to cause bending deformation, torsion deformation and / or expansion / contraction deformation. A durability test apparatus for a medical test object.   The control means controls the operation of the operation means so that the bending deformation, torsional deformation and / or expansion / contraction deformation is performed in synchronization with a periodic change in the pressure and / or flow rate of the test fluid. The durability test apparatus for a medical test object according to claim 1.   3. The operation of the operation means is controlled by the control means so that the deformation of the installation portion starts at a timing when the pressure or flow rate of the test fluid reaches a predetermined value. Durability testing equipment for medical test objects.   The control means controls the operation of the operation means so as to match a timing at which the pressure or flow rate of the test fluid is maximized with a timing at which the installation portion is maximally deformed. The durability test apparatus of the medical test object as described. A medical test object is installed in an installation part provided in the middle of a flow path for circulating a predetermined test fluid, and a flow simulating the blood flow state of the human body is given to the test fluid to A method for performing a durability test,
The test fluid is pulsated and circulated through the flow path, and the installation portion is periodically externally connected based on periodic changes in the pressure and / or flow rate of the test fluid. A medical test object characterized by performing the durability test while repeatedly bending, twisting, and / or expanding and contracting the installation portion in synchronization with a flow state of the test fluid by applying a load. Durability test method.

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