CN113520353B

CN113520353B - Use method of catheter simulator

Info

Publication number: CN113520353B
Application number: CN202110811105.5A
Authority: CN
Inventors: 熊双涛; 郑欲晓
Original assignee: Insight Lifetech Co Ltd
Current assignee: Insight Lifetech Co Ltd
Priority date: 2018-12-31
Filing date: 2018-12-31
Publication date: 2023-06-16
Anticipated expiration: 2038-12-31
Also published as: CN113520354A; CN113520354B; CN109567776A; CN109567776B; CN113520353A

Abstract

The present disclosure relates to a method of using a catheter simulator for testing an FFR host system, the catheter simulator comprising a generation module, a processing module, an adjustment module, and a matching module having a first wheatstone half-bridge circuit, the FFR host system having a second wheatstone half-bridge circuit, the first wheatstone half-bridge circuit being matched with the second wheatstone half-bridge circuit to electrically match the catheter simulator to the FFR host system, a blood pressure periodic signal being generated by the generation module, the blood pressure periodic signal being converted to a blood pressure differential signal by the processing module, the blood pressure differential signal being adjusted by the adjustment module to obtain a low-amplitude differential signal, the low-amplitude differential signal being output by the matching module as a matching differential signal matching the FFR host system, the FFR host system receiving the matching differential signal and generating a fractional flow reserve based on the matching differential signal. According to the present disclosure, the reliability of the test can be improved.

Description

Use method of catheter simulator

The application is filing date2018, 12, 31 daysApplication number is201811650741.9The invention is named asFor use in Catheter simulator for testing FFR host systemIs a divisional application of the patent application of (2).

Technical Field

The present disclosure relates to a method of using a catheter simulator.

Background

In many cardiovascular diseases such as coronary heart disease, stenosis of the blood vessel (caused by e.g. plaque of the blood vessel) affects the normal supply of blood, and when the blood vessel is further stenosed or even blocked, serious lesions such as myocardial infarction may be caused. Percutaneous Coronary Intervention (PCI) is currently a relatively effective treatment.

In recent years, the use of fractional flow reserve (Fractional Flow Reverse, FFR for short) to evaluate the extent to which stenotic lesions block blood flow through blood vessels has become increasingly popular in order to accurately determine whether a patient is actually in need of interventional therapy. FFR refers to the ratio of the maximum blood flow that can be obtained in the region of the myocardium supplied by the blood vessel to the maximum blood flow that can be obtained in the theoretically normal case of the same region in the case where there is a stenotic lesion in the coronary artery, i.e., the ratio of the average blood pressure (Pd) in the coronary artery at the far end of the stenosis in the state of maximum congestion of the myocardium to the average blood pressure (Pa) in the aortic arch at the mouth of the coronary artery. In order to calculate FFR for a given stenosis (i.e., where a stent is likely to be placed) within a vessel, blood pressure readings of the distal side of the stenosis (e.g., downstream of the stenosis, away from the aorta) and the proximal side of the stenosis (e.g., upstream of the stenosis, near the aorta) need to be measured and acquired, respectively. Clinical studies have shown that the higher the stenosis, the lower the FFR, and whether the FFR is less than an evaluation value (e.g., 0.8) can be a useful criterion based on which a physician can decide whether to perform an interventional procedure on such a patient. The validity of this criterion has also been demonstrated by a number of large clinical studies in europe and america (e.g., FAME clinical studies).

As a method of measuring FFR of a patient, there is a method using an FFR measurement system, for example. The system mainly comprises a pressure measuring conduit, a pressure sensor and an FFR host system. The pressure measuring catheter is used for measuring Pd values in blood vessels, the pressure sensor is used for measuring Pa values, the FFR host system is provided with Pd interfaces and Pa interfaces, the Pd values and the Pa values can be read, and after processing and analysis, FFR is calculated.

In order to make the measured FFR more accurate, we need to test the function of the FFR host system to verify its eligibility. Currently, functional testing of FFR mainframe systems is accomplished primarily by applying a measurement pressure conduit to an external hydraulic signal source. Specifically, a test platform including a hydraulic signal source is used to simulate a blood vessel in a patient and blood flow in the blood vessel, then a pressure measurement catheter is used to measure a pressure value (corresponding to the Pd value) of the hydraulic signal source, the measured Pd value is transmitted to an FFR host system, an existing pressure sensor simulator transmits the Pa value to the FFR host system, and the FFR host system calculates FFR (measured value) according to the simulated Pa value and the measured Pd value.

And comparing the measured value with an actual value set by the test platform to realize the test of the function of the FFR host system. However, in the existing testing method, the stability requirement on the hydraulic signal source is very high, the hydraulic signal source is easily affected by external vibration to cause pressure fluctuation, so that the testing result is unreliable, and an actual pressure measuring conduit is required to be used in the testing process, so that the loss of the pressure measuring conduit is caused.

Disclosure of Invention

The present disclosure has been made in view of the above-mentioned conventional art, and an object thereof is to provide a catheter simulator capable of accurately and conveniently testing an FFR host system.

To this end, the present disclosure provides a catheter simulator for testing an FFR host system, comprising: a generation module that generates a blood pressure periodic signal based on a human blood pressure characteristic and an excitation voltage generated by the FFR host system; the processing module is used for processing the blood pressure periodic signal to generate a blood pressure differential signal; the adjusting module is used for adjusting the amplitude of the blood pressure differential signal to generate a low-amplitude differential signal; and a matching module for outputting the low-amplitude differential signal as a matched differential signal that matches the host system, wherein the FFR host system generates Fractional Flow Reserve (FFR) based on the matched differential signal.

In the catheter simulator for testing the FFR host system, the generation module generates the blood pressure periodic signal based on the human blood pressure characteristic and the excitation voltage generated by the FFR host system, and the blood pressure differential signal is generated after the blood pressure periodic signal is processed by the processing module, so that the influence of external vibration on a hydraulic signal source can be effectively reduced, the reliability of testing is improved, the operation of generating the blood pressure periodic signal is simple, the difficulty of building a testing platform is reduced, the catheter simulator is used for replacing a catheter, the loss of the catheter can be reduced, and the cost of testing is reduced.

In addition, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the generating module includes a processing unit for generating a digital signal based on a blood pressure characteristic of a human body, and a converting unit for converting the digital signal into the blood pressure periodic signal. Therefore, the interference of the external environment to the signal source required by the test can be reduced, and the blood pressure periodic signal which effectively simulates the blood pressure characteristic of the human body can be generated.

Additionally, in the catheter simulator for testing FFR host systems related to the present disclosure, optionally, the human blood pressure characteristic comprises a human blood pressure frequency. Thus, a blood pressure periodic signal having a frequency including the blood pressure of the human body can be effectively simulated.

In addition, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the conversion unit has a digital-to-analog conversion subunit for converting the digital signal into an analog signal based on the excitation voltage, and an integration subunit for performing a filter process on the analog signal to generate the blood pressure periodic signal. . Therefore, the excitation voltage from the FFR host system can be better matched with the matched differential signal generated by the catheter simulator and the FFR host system, the accuracy of the blood pressure periodic signal can be effectively improved due to the stable excitation voltage, and the filtering processing of the integration subunit is beneficial to enabling the whole blood pressure periodic signal to be smoother.

In addition, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the processing module is a differential conversion unit for converting the blood pressure periodic signal as a single-ended signal into the blood pressure differential signal. Therefore, noise brought by the external environment to the signal can be effectively reduced.

In addition, in the catheter simulator for testing FFR host system according to the present disclosure, optionally, the adjustment module performs an attenuation process with a preset multiple on the blood pressure differential signal. Therefore, the signal amplitude of the blood pressure differential signal can be effectively reduced, so that the requirement of the FFR host system on the signal amplitude is met.

Additionally, in the catheter simulator for testing FFR host systems related to the present disclosure, optionally, the matching module has a first wheatstone half-bridge circuit, the FFR host system has a second wheatstone half-bridge circuit, and the first wheatstone half-bridge circuit is matched with the second wheatstone half-bridge circuit to constitute a wheatstone full-bridge circuit. Thus, the matching of the catheter simulator to the host system in circuit can be achieved by a Wheatstone full bridge circuit.

In addition, in the catheter simulator for testing FFR host system according to the present disclosure, optionally, the matching module further has a memory for storing calibration parameters of the catheter, the calibration parameters including a first functional relationship between a first resistance value of a constant-value resistive element of the catheter and a temperature of the catheter, and a second functional relationship between a second resistance value of a varistor element of the catheter and an external pressure to which the catheter is subjected. Under the condition, the host system can be calibrated based on the calibration parameters of the resistance of the catheter and the temperature of the catheter, so that the temperature factor of the catheter is fully considered in the test process, the reliability of the test is improved, and the accuracy of the test is further improved through the functional relation between the resistance value and the pressure.

In addition, in the catheter simulator for testing FFR host systems related to the present disclosure, optionally, the first wheatstone half-bridge circuit has a variable resistance element. Thus, the catheter simulator can be made to better simulate the catheter by adjusting the resistance value of the variable resistance element of the first Wheatstone half-bridge circuit.

Further, in the catheter simulator for testing an FFR host system according to the present disclosure, optionally, the matching module adjusts a resistance value of the variable resistance element based on the calibration parameter, a resistance of the catheter, and a circuit impedance of the FFR host system to match the matching differential signal with the FFR host system. In this case, the matched differential signal generated by the catheter simulator can be further better matched to the host system.

According to the method and the device, the influence of external vibration on a hydraulic signal source can be effectively reduced, the reliability of testing is improved, the operation of generating a blood pressure periodic signal is simple, the difficulty of building a test platform is reduced, a catheter simulator is used for replacing a pressure measurement catheter, the loss of the pressure measurement catheter can be reduced, and the cost of testing is reduced.

Drawings

Embodiments of the present disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram illustrating the application of a catheter simulator in accordance with embodiments of the present disclosure;

FIG. 2 is a block diagram illustrating a catheter simulator in accordance with an embodiment of the present disclosure;

FIG. 3 is a block diagram illustrating a generation module of a catheter simulator in accordance with an embodiment of the present disclosure;

FIG. 4 is a block diagram illustrating a conversion unit of a generation module of a catheter simulator in accordance with an embodiment of the present disclosure;

FIG. 5 is a block diagram illustrating a matching module of a catheter simulator in accordance with embodiments of the present disclosure;

FIG. 6 is a block diagram illustrating an FFR host system to which a catheter simulator in accordance with an embodiment of the present disclosure is applied;

FIG. 7 is a Wheatstone full-bridge circuit diagram illustrating a matching of a first Wheatstone half-bridge circuit of a matching module of a catheter simulator in accordance with an embodiment of the present disclosure with a second Wheatstone half-bridge circuit of an applied FFR host system; and

fig. 8 is a flowchart illustrating the operation of a catheter simulator according to an embodiment of the present disclosure.

Detailed Description

All references cited in this disclosure are incorporated by reference in their entirety as if fully set forth. Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

A general guide for many of the terms used in this application is provided to those skilled in the art. Those skilled in the art will recognize many methods and materials similar or equivalent to those described in the present disclosure that can be used in the practice of the present disclosure. Indeed, the present disclosure is in no way limited to the described methods and materials.

Fig. 1 is a schematic diagram showing an application of a catheter simulator according to an embodiment of the present disclosure. Fig. 2 is a block diagram illustrating a catheter simulator according to an embodiment of the present disclosure.

A catheter simulator 1 for testing an FFR host system 2 (hereinafter sometimes referred to as "host system 2") according to embodiments of the present disclosure may include a generation module 10, a processing module 20, an adjustment module 30, and a matching module 40. In the catheter simulator 1, the generation module 10 may generate the blood pressure cycle signal Vt based on the human blood pressure characteristics and the excitation voltage Vi generated by the FFR host system 2. In addition, the processing module 20 may be configured to process the blood pressure periodic signal Vt to generate a blood pressure differential signal Vd. The adjustment module 30 may be configured to adjust the signal amplitude of the blood pressure differential signal Vd to generate a low amplitude differential signal Vl. In addition, matching module 40 may be configured to output low-amplitude differential signal Vl as a matching differential signal Vm that matches FFR host system 2, where FFR host system 2 generates Fractional Flow Reserve (FFR) based on matching differential signal Vm.

In the present embodiment, the blood pressure periodic signal Vt generated by the generating module 10 in the form of an electrical signal is relatively stable, and thus, the signal source of the test platform can be effectively reduced from being susceptible to external vibrations. In addition, the generating module 10 can simulate the human blood pressure signal in a wider frequency range, so that the accuracy of the test is effectively improved, the operation of generating the blood pressure periodic signal Vt is simple, the difficulty of building a test platform is reduced, and the catheter simulator 1 is used for replacing a pressure measuring catheter, so that the cost of the test can be greatly reduced. In addition, since the catheter simulator 1 has the first wheatstone half-bridge circuit 41, the FFR host system 2 has the second wheatstone half-bridge circuit 2a (see fig. 6 described later), the catheter simulator 1 and the FFR host system 2 can be more optimally matched.

The catheter simulator 1 according to the present embodiment is particularly suitable for simulating the Pd value obtained by a pressure measurement catheter in a measurement system.

Fig. 3 is a block diagram illustrating a generation module of a catheter simulator according to an embodiment of the present disclosure. Fig. 4 is a block diagram showing a conversion unit of a generation module of a catheter simulator according to an embodiment of the present disclosure. Fig. 5 is a block diagram illustrating a matching module of a catheter simulator according to an embodiment of the present disclosure. Fig. 6 is a block diagram illustrating an FFR host system to which a catheter simulator according to an embodiment of the present disclosure is applied.

In the present embodiment, the generation module 10 may generate the blood pressure cycle signal Vt based on the human blood pressure characteristic and the excitation voltage Vi generated by the FFR host system 2.

In this embodiment, the "human blood pressure characteristic" generally refers to the fluctuation of the blood pressure in a blood vessel with the frequency and amplitude of a certain characteristic generated by the beating of the heart when the heart of the human body pumps blood. In some examples, the human blood pressure characteristics primarily include frequency, amplitude, etc. of human blood pressure fluctuations. In the present embodiment, the "blood pressure periodic signal" Vt generally refers to a signal having blood pressure characteristics of a human body and having repeated periodic changes. In some examples, the blood pressure periodic signal may be a sinusoidal signal.

In the present embodiment, the excitation voltage Vi generated by the FFR host system 2 generally refers to a voltage generated by the FFR host system 2 and transmitted to the catheter simulator 1. The use of the excitation voltage Vi generated by FFR host system 2 facilitates a better match of catheter simulator 1 and FFR host system 2.

In addition, in the present embodiment, the generation module 10 may include a processing unit 11 and a conversion unit 12. In the present embodiment, in the generation module 10, the processing unit 11 may be used to generate a digital signal based on the blood pressure characteristics of the human body.

In the present embodiment, the "digital signal" generated by the processing unit 11 generally means a signal in which the independent variable is discrete and the dependent variable is also discrete. In a computer, the magnitude of a digital signal is often represented by a binary number with a limit. In some examples, the digital signal may include frequency characteristics of human blood pressure.

In some examples, the processing unit 11 may be a micro-processor (MCU), a Central Processing Unit (CPU), a field programmable array (FPGA) with processor functions, or the like.

In addition, the conversion unit 12 may be used to convert the digital signal into a blood pressure cycle signal Vt. This can generate the blood pressure periodic signal Vt having the blood pressure characteristic of the human body. In some examples, the blood pressure periodic signal Vt may be a sinusoidal signal.

In addition, in the present embodiment, in some examples, the conversion unit 12 may have a digital-to-analog conversion subunit 121 for converting a digital signal into an analog signal based on the excitation voltage Vi, and an integration subunit 122 for performing filter processing on the analog signal to generate the blood pressure cycle signal Vt. Thus, the excitation voltage Vi derived from the FFR host system 2 can better match the signal generated by the catheter simulator 1 with the FFR host system 2, and the stable excitation voltage Vi can effectively improve the accuracy of the blood pressure cycle signal Vt, and the filter processing of the integration unit helps to make the blood pressure cycle signal Vt smoother as a whole.

In this embodiment, the filtering process performed by the integrating subunit 122 can filter the portion with a significant difference in the signals, so as to make the blood pressure periodic signal Vt smoother. In some examples, the integrating subunit 122 may filter out high frequency signals in the blood pressure periodic signal Vt.

Additionally, in some examples, the integration subunit 122 may include an integration circuit capable of performing a filtering process.

In the present embodiment, the processing module 20 may be configured to convert the blood pressure periodic signal Vt, which is a single-ended signal, into the blood pressure differential signal Vd. Therefore, noise brought by the external environment to the signal can be effectively reduced.

In this embodiment, the single-ended signal and the differential signal are generally referred to as signal transmission technology. Single-ended signals generally refer to signals having a reference terminal and a signal terminal, the reference terminal being generally a ground terminal; the differential is generally to perform differential transformation on a single-ended signal, and output two signals, one in phase with the original signal and one in opposite phase with the original signal, wherein the difference between the two signals is the differential signal. When being interfered by external environment, the two signals change at the same time, so the difference value between the two signals is usually small, namely the change of the differential signal is usually small, and the differential signal has stronger anti-interference capability.

In addition, in the present embodiment, the adjustment module 30 may perform the attenuation process with a preset multiple on the blood pressure difference signal Vd. Thus, the signal amplitude can be reduced to meet the signal amplitude requirement of the FFR host system 2. In some examples, the preset multiple may be 100 to 1000 or a corresponding order of magnitude.

In the present embodiment, the adjustment module 30 performs attenuation processing on the blood pressure difference signal Vd, that is, performs amplification processing with a preset multiple on the blood pressure difference signal Vd. Specifically, since the signal amplitude transmitted by the actual pressure measurement catheter is usually small, the FFR host system usually needs to process the signal with a low amplitude level, while in the catheter simulator 1, the blood pressure periodic signal Vt generated by the generating module 10 is high in amplitude, and in order to meet the requirement of the FFR host system 2 on the signal amplitude, the attenuation process needs to be performed on the blood pressure differential signal Vd to obtain the low amplitude differential signal Vl. In other words, the differential blood pressure signal Vd is amplified, and the amplified signal amplitude is smaller than the original signal amplitude. In some examples, the original signal amplitude may be 1000 times the amplified signal amplitude.

FIG. 7 is a Wheatstone full-bridge circuit diagram illustrating a matching of a first Wheatstone half-bridge circuit of a matching module of a catheter simulator in accordance with an embodiment of the present disclosure with a second Wheatstone half-bridge circuit of an applied FFR host system.

In this embodiment, the matching module 40 may have a first wheatstone half-bridge circuit 41, and the ffr host system 2 generally has a second wheatstone half-bridge circuit 2a, and the first wheatstone half-bridge circuit 41 is matched with the second wheatstone half-bridge circuit 2a to form a wheatstone full-bridge circuit. Thus, the catheter simulator 1 and FFR host system 2 can be electrically matched.

In the present disclosure, a wheatstone half-bridge circuit and a wheatstone full-bridge circuit are generally one type of circuit connection. The Wheatstone half-bridge circuit comprises 2 parallel circuits and 2 resistors, wherein each parallel circuit comprises 1 resistor. The wheatstone full-bridge circuit comprises 2 parallel lines and 4 resistors, wherein each parallel line comprises two resistors. The Wheatstone half-bridge circuit can be regarded as half of the Wheatstone full-bridge circuit.

In this embodiment, in some examples, the first wheatstone half-bridge circuit 41 may include two variable resistance elements Rx1, rx2, with the resistance values of the variable resistance elements Rx1, rx2 adjusted to achieve a simulation of the resistance of the internal circuitry in the pressure measurement conduit.

In the wheatstone full-bridge circuit shown in fig. 7, the resistors R1 and R2 constitute a second wheatstone half-bridge circuit 2a, the resistors Rx1 and Rx2 constitute a first wheatstone half-bridge circuit 41, and the second wheatstone half-bridge circuit 2a and the first wheatstone half-bridge circuit are connected to constitute the wheatstone full-bridge circuit.

In some examples, a variable resistive element Rx1 may be used to simulate a constant value resistive element in a pressure measurement conduit, and a variable resistive element Rx2 may be used to simulate a piezoresistive element in a pressure measurement conduit.

In some examples, variable resistive element Rx1 may also be used to simulate a piezoresistive element in a pressure measurement conduit, and variable resistive element Rx2 may be used to simulate a fixed resistive element in a pressure measurement conduit.

In addition, in the present embodiment, the matching module 40 may further have a memory 42 for storing calibration parameters of the conduit, where the calibration parameters may include a first functional relationship between a first resistance value of a constant-value resistive element of the pressure measurement conduit and a temperature of the pressure measurement conduit, and a second functional relationship between a second resistance value of a varistor element of the pressure measurement conduit and an external pressure to which the pressure measurement conduit is subjected. Therefore, the temperature factor can be fully considered in the operation process of the host system, and the reliability of the test is improved.

In this embodiment, the varistor element generally refers to a resistor element whose resistance value changes with a change in pressure. In some examples, the resistance of the piezoresistive element may be positively or negatively correlated with pressure.

In this embodiment, the variable resistive element generally refers to a resistive element that can be manually adjusted to change a resistance value. The catheter simulator 1 can simulate the pressure measurement catheter by simulating the circuit characteristics inside the pressure measurement catheter, for example, by adjusting the variable resistive element so that the resistance value of the first wheatstone half-bridge circuit 41 is equal to the resistance value of the internal circuit of the pressure measurement catheter.

In addition, in the present embodiment, the matching module 40 may adjust the resistance value of the variable resistive element based on the calibration parameter, the resistance of the pressure measurement conduit, and the circuit impedance of the FFR host system 2 so that the matching differential signal Vm matches the FFR host system 2. Thus, the FFR host system 2 can process the signal generated by the catheter simulator 1 to generate FFR, and the qualification of the FFR host system 2 can be tested by comparing the measured value with the set value.

In some examples, in the catheter simulator 1 in the present disclosure, the blood pressure periodic signal Vt may be a sinusoidal signal.

In some examples, the catheter simulator 1 to which the present disclosure relates, the frequency range of the digital signal may be 0 to 5 hertz (Hz). In some examples, the frequency of the digital signal may be selected to be 0 hertz, 1 hertz, 2 hertz, 3 hertz, 4 hertz, or 5 hertz.

In some examples, the catheter simulator 1 described in the present disclosure may be used to simulate a human blood pressure signal. In some examples, the catheter simulator 1 in the present disclosure may simulate digital signals of one or more specific frequencies.

In the present embodiment, the processing unit 11 may have a microcomputer circuit therein, and may process an input power signal based on the frequency characteristics of the blood pressure of the human body to generate a digital signal, and the frequency and amplitude of the digital signal may be adapted to the characteristics of the actual blood pressure signal of the human body.

In the catheter simulator 1 in the present disclosure, the conversion unit 12 of the generation module 10 may convert the above-described digital signal into an analog signal that is a blood pressure periodic signal Vt. In some examples, the blood pressure periodic signal Vt may be a sinusoidal signal.

In some examples, the processing module 20 of the catheter simulator 1 in the present disclosure may convert the single-ended signal as the blood pressure cycle signal Vt into a differential signal as the blood pressure differential signal Vd. Therefore, interference suffered in the signal transmission process can be effectively reduced, and the blood pressure differential signal Vd is more accurate and reliable.

In some examples, the adjustment module 30 in the catheter simulator 1 in the present disclosure may attenuate the blood pressure differential signal Vd.

In some examples, the adjustment module 30 of the catheter simulator 1 in the present disclosure may have an amplification circuit, and may perform attenuation processing of the input blood pressure differential signal Vd by a preset multiple. Because the signal in the pressure measurement conduit is small, the signal of the common signal source needs to be attenuated by a preset multiple without losing great precision, so as to achieve a more approximate simulation effect.

In some examples, the matching module 40 may have a first wheatstone half-bridge circuit 41 and the ffr host system 2 may have a second wheatstone half-bridge circuit 2a.

In the present embodiment, FFR host system 2 needs to calculate and process matching differential signal Vm transmitted from catheter simulator 1, and thus obtains FFR. In operation, it is necessary to use some fixed values, such as the resistance values of R1, R2 in the second wheatstone half-bridge circuit 2a in the FFR host system 2, the resistance values of Rx1, rx2 in the first wheatstone half-bridge circuit 41 in the catheter simulator 1, the functional relationship between the resistance values of the piezoresistive elements of the internal circuit of the pressure measurement catheter and the pressure, and the functional relationship between the resistance values of the fixed-value resistive elements of the internal circuit of the pressure measurement catheter and the catheter temperature. In this way, the pressure measurement catheter internal circuit is simulated using the first wheatstone half-bridge circuit 41 provided in the matching module 40, thereby realizing that the second wheatstone half-bridge circuit 2a in the FFR host system 2 matches with the first wheatstone half-bridge circuit 41 provided in the matching module 40 to constitute a wheatstone full-bridge circuit.

The method of using the catheter simulator 1 will be described in detail below with reference to the flowchart shown in fig. 8.

In step S10, since the catheter simulator 1 is connected to the FFR host system 2, the excitation voltage Vi generated by the FFR host system can be transmitted to the catheter simulator 1.

In step S20, the processing unit 11 of the generation module 10 of the catheter simulator 1 generates a digital signal having the frequency characteristic of the human blood pressure. The digital-to-analog conversion subunit 121 of the conversion unit 12 may then convert the digital signal into an analog signal based on the excitation voltage Vi described above. Then, the integration subunit 122 performs a filtering process on the analog signal to obtain a smoothed blood pressure cycle signal Vt.

In step S30, the processing module 20 of the catheter simulator 1 has a single-ended-transfer-differential function, and can convert the single-ended signal, which is the blood pressure periodic signal Vt, into the blood pressure differential signal Vd. Therefore, noise brought by the external environment to the signal can be effectively reduced.

In step S40, the adjusting module 30 of the catheter simulator 1 has a circuit-wise amplifying function, and can perform attenuation processing on the blood pressure differential signal Vd with higher signal amplitude, so as to obtain a low-amplitude differential signal Vl with lower signal amplitude. This allows the FFR host system 2 to meet the signal amplitude requirements, allowing the catheter simulator 1 to better match the FFR host system 2.

In step S50, the matching module 40 of the catheter simulator 1 has a first wheatstone half-bridge circuit 41 and a memory 42, and the first wheatstone half-bridge circuit 41 may be matched with the second wheatstone half-bridge circuit 2a of the FFR host system to form a wheatstone full-bridge circuit as shown in fig. 7, through which the low-amplitude differential signal Vl is output as the matching differential signal Va.

In step S60, the FFR host system 2 receives the matching differential signal Va from the catheter simulator 1, and performs analysis processing on the matching differential signal Va to calculate FFR. The calculated measured value is then compared with the set point of the test platform. The testing work of the FFR host system is completed by comparing the difference between the measured value and the set value to evaluate the function of the FFR host system 2.

While the disclosure has been described in detail in connection with the drawings and embodiments, it should be understood that the foregoing description is not intended to limit the disclosure in any way. Modifications and variations of the present disclosure may be made as desired by those skilled in the art without departing from the true spirit and scope of the disclosure, and such modifications and variations fall within the scope of the disclosure.

Claims

1. A method for using a catheter simulator,

the catheter simulator is used for simulating circuit characteristics inside a pressure measurement catheter to test an FFR host system, the catheter simulator comprises a generating module, a processing module, an adjusting module and a matching module with a first Wheatstone half-bridge circuit, the FFR host system is provided with a second Wheatstone half-bridge circuit,

the using method comprises the following steps:

the first Wheatstone half-bridge circuit is matched with the second Wheatstone half-bridge circuit to form a Wheatstone full-bridge circuit, so that the catheter simulator is matched with the FFR host system in circuit, the catheter simulator receives excitation voltage generated by the FFR host system, the generation module generates a blood pressure periodic signal based on human blood pressure characteristics and the excitation voltage, the processing module converts the blood pressure periodic signal into a blood pressure differential signal, the adjustment module adjusts the blood pressure differential signal to obtain a low-amplitude differential signal, the matching module outputs the low-amplitude differential signal into a matching differential signal matched with the FFR host system, and the FFR host system receives the matching differential signal and generates a blood flow reserve fraction based on the matching differential signal.

2. The method of use according to claim 1, wherein:

the matching module also has a memory for storing calibration parameters of the pressure measurement conduit, the calibration parameters including a first functional relationship between a first resistance value of a constant value resistive element of the pressure measurement conduit and a temperature of the pressure measurement conduit, a second functional relationship between a second resistance value of a piezoresistive element of the pressure measurement conduit and an ambient pressure to which the pressure measurement conduit is subjected.

3. A method of use as claimed in claim 2, wherein:

the matching module adjusts a resistance value of a variable resistance element of the first Wheatstone half-bridge circuit based on the calibration parameter, a resistance of the pressure measurement conduit, and a circuit impedance of the FFR host system to match the matching differential signal to the FFR host system.

4. The method of use according to claim 1, wherein:

the generation module comprises a processing unit for generating a digital signal based on the blood pressure characteristics of the human body, and a conversion unit for converting the digital signal into the blood pressure periodic signal.

5. The method of use according to claim 4, wherein:

the digital signal has a frequency in the range of 0 to 5 hertz.

6. The method of use according to claim 4, wherein:

the human blood pressure characteristics include frequency and amplitude of blood pressure.

7. The method of use according to claim 4, wherein:

the conversion unit has a digital-to-analog conversion subunit for converting the digital signal into an analog signal based on the excitation voltage, and an integration subunit for performing a filter process on the analog signal to generate the blood pressure periodic signal.

8. The method of use according to claim 1, wherein:

the blood pressure periodic signal is a sine signal.

9. The method of use according to claim 1, wherein:

the adjustment module carries out attenuation processing with preset times on the blood pressure differential signals, wherein the preset times are 100-1000.

10. The method of use according to claim 1, wherein:

the FFR host system is tested for eligibility by comparing the fractional flow reserve measurement to a set point for the catheter simulator.