A motorized retraction system and method for intravascular functional assessment

Abstract

This invention discloses an electrically operated retraction system and method for intravascular functional assessment, belonging to the field of medical device technology. The system includes a retraction drive unit, a controller, and a pressure catheter sleeve. The pressure catheter sleeve is a hollow, elastic tubular structure fitted onto the tail end of a pressure microcatheter. It is configured such that, when clamped by a Y-valve, a fluid seal is formed between the Y-valve and the pressure catheter sleeve, while simultaneously allowing the pressure microcatheter to slide axially with low friction within the inner cavity of the pressure catheter sleeve. The controller responds to a start command, controlling the retraction drive unit to perform a continuous, uniform retraction action. By introducing the pressure catheter sleeve, this invention decouples the mechanical contradiction between the Y-valve pressure seal and the catheter retraction movement. It enables safe, smooth, and continuous retraction of the pressure microcatheter while ensuring the fidelity of the pressure measurement signal, avoiding the risk of dragging the entire interventional system and significantly improving operational safety and the accuracy of functional assessment.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an electrically operated retraction system and method for intravascular functional assessment. Background Technology

[0002] Fractional flow reserve (FR) measurement has become the "gold standard" for assessing the functional significance of coronary artery stenosis. In clinical practice, the "pullback" technique is often used to comprehensively assess vascular pressure distribution and identify diffuse or tandem lesions. This technique involves withdrawing a pressure microcatheter from the distal end of the vessel to the proximal end, continuously recording pressure changes, and generating a pressure-distance curve. While traditional electrically operated uniform-speed pullback devices have solved the problem of uneven manual pullback speed, they have revealed a deeper and more challenging operational contradiction: the sealing dilemma of the Y-valve.

[0003] To ensure accurate pressure measurements, the Y-valve must be tightened to create a reliable hemostatic seal around the catheter, preventing pressure signal distortion due to leakage. However, this necessary tightening creates significant frictional resistance on the pressure microcatheter. When the electric retraction device is activated, this frictional force is sufficient to pull the entire guiding system (including the guiding catheter and the Y-valve itself) outwards, potentially causing uncontrolled catheter tip positioning and serious complications such as vascular injury. Conversely, loosening the Y-valve to avoid this risk results in seal failure, leading to inaccurate pressure readings and potential bleeding risks. This irreconcilable physical contradiction between "sealing" and "smooth movement" constitutes a fundamental obstacle to the safe clinical application of existing electric retraction technology and is a technical problem urgently needing to be solved in this field. Summary of the Invention

[0004] The main objective of this invention is to provide an electrically retractable system and method for intravascular functional assessment, aiming to fundamentally resolve the technical contradiction in the prior art between maintaining pressure sealing and allowing smooth catheter retraction of the Y valve.

[0005] To achieve the above objectives, the first aspect of this invention provides an electrically driven retraction system for intravascular functional assessment. This system includes a retraction drive unit and a controller, with its core innovation being the introduction of a novel component: a pressure catheter sleeve. This pressure catheter sleeve is a hollow tubular structure that is fitted over the end of a pressure microcatheter during use. Its ingenuity lies in the specific design of its materials and dimensions, ensuring that when the Y-valve is tightened, the sealing force of the Y-valve acts entirely on the outside of this "static" catheter sleeve, forming a stable and reliable fluid seal; while the "dynamic" pressure microcatheter can slide freely axially within the internal cavity of this catheter sleeve with extremely low friction. Thus, by establishing a structure that separates the static sealing interface from the dynamic sliding interface, this invention completely decouples the previously coupled mechanical contradictions. The controller is configured to respond to the operator's activation command, driving the retraction unit to perform a smooth, continuous, uniform retraction, and simultaneously acquiring data to generate a high-fidelity pressure-distance curve.

[0006] Optionally, the pressure catheter sleeve is made of elastic polymer materials such as medical-grade silicone rubber, ensuring good sealing compliance and biocompatibility.

[0007] Optionally, the inner wall of the pressure catheter sleeve may be coated with a low-friction coating to further reduce the resistance when the microcatheter slides, making the retraction action infinitely close to the ideal state.

[0008] Optionally, the system can also integrate three-dimensional reconstruction capabilities, fusing one-dimensional pressure-distance curve data with the patient's actual three-dimensional anatomical structure of blood vessels to generate an intuitive three-dimensional pressure gradient map, providing an unprecedented dimension of information for clinical decision-making.

[0009] A second aspect of this invention provides an electrically operated retraction method for intravascular functional assessment. This method utilizes the aforementioned system, and its key steps are as follows: first, a microcatheter fitted with a pressure catheter sheath is inserted into the blood vessel; then, the Y-valve is tightened to securely clamp and seal it onto the "static" catheter sheath. Subsequently, the retraction drive unit is activated, allowing the pressure microcatheter to retract continuously and uniformly within the catheter sheath while data acquisition is performed.

[0010] The beneficial effects of this invention are as follows: By designing a pressure catheter sleeve, the risk of retraction force acting on the Y valve and guiding system is completely eliminated, fundamentally preventing the serious complication of pulling out the entire interventional system, making the electric retraction operation highly safe.

[0011] Because the Y valve can be fully tightened to achieve the best sealing effect, it is not affected by friction, thus ensuring the high fidelity and signal-to-noise ratio of the pressure measurement signal, providing a reliable data source for generating accurate functional evaluation curves.

[0012] After the mechanical constraints are removed, the system can achieve a truly smooth, continuous, and uniform retraction. The resulting pressure-distance curve can more realistically reflect the hemodynamic changes within the blood vessels, thus improving the accuracy of diagnosis. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the overall functional modules of an electric retraction system according to an embodiment of the present invention.

[0015] Figure 2 This is a flowchart of the continuous uniform speed retraction method according to a preferred embodiment of the present invention.

[0016] Figure 3 This is a structural schematic diagram illustrating the assembly relationship of a Y-type valve, a pressure conduit sleeve, and a pressure microcatheter, according to a preferred embodiment of the present invention. Figure 4 This is a partial cross-sectional schematic diagram illustrating the collaborative working relationship between the pressure conduit sleeve, the Y valve, and the pressure microcatheter, according to a preferred embodiment of the present invention.

[0017] Figure 5 This is a schematic diagram of a system functional module that integrates three-dimensional reconstruction and fusion functions according to an embodiment of the present invention.

[0018] Figure 6 This is a schematic diagram of the gated step-by-step withdrawal timing relationship based on electrocardiogram signals, according to another embodiment of the present invention.

[0019] Figure 7 This is a flowchart of a withdrawal method according to another embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0023] This embodiment provides an electrically operated retraction system and method for intravascular functional assessment. In one specific implementation, this method employs an innovative mechanical structure including a pressure catheter sheath, coupled with precise motor control and a synchronous data acquisition strategy, to achieve safe, smooth, continuous, and uniform retraction of the pressure microcatheter. This method solves the technical problems of high operational risk and compromised data accuracy caused by the conflict between the sealing requirements of the Y-valve and the movement requirements of the catheter in existing technologies, achieving the beneficial effect of significantly improving surgical safety and the accuracy of functional assessment.

[0024] Reference Figure 1 The electrically driven reflux system 100 described in this embodiment includes a physiological signal acquisition module 110, a retraction drive unit 120, and a controller 130. Furthermore, a core component of this system is a pressure catheter sleeve, the structure and function of which will be described in detail below.

[0025] The pressure conduit sleeve 310 (e.g.) Figure 3 (As shown) is a separate sterile medical component. Structurally, it is a hollow tubular structure. In one specific implementation, the total length of the pressure catheter sleeve 310 is set to 50 centimeters (cm). The length needs to be long enough to cover the entire sliding stroke of the pressure microcatheter 320 during the entire retraction process (typically not exceeding 150 mm), and to allow sufficient margin to accommodate pressure microcatheters of different brands and lengths, as well as the operator's operating space outside the body.

[0026] The dimensions of the pressure catheter sleeve 310 are strictly controlled to ensure mechanical and functional compatibility with standard interventional surgical instruments, particularly the pressure microcatheter 320 and Y-valve 330. For example, its inner diameter is designed to be 0.015 inches (approximately 0.381 mm). This inner diameter is slightly larger than the outer diameter of mainstream pressure microcatheters on the market (such as St. Jude Medical's PressureWire™ X Guidewire, which has a diameter of 0.014 inches), creating a small, precisely controlled annular gap between them. This gap is the physical basis for low-friction sliding; it is small enough to provide stable guidance after lubrication application, preventing the microcatheter from wobbling or bending within the sleeve, yet large enough to avoid excessive contact stress between them. For example, the manufacturing tolerance of this inner diameter is controlled within ±0.005 mm to ensure batch-to-batch product performance consistency.

[0027] The wall thickness of the pressure conduit sleeve 310 is set to 0.2 mm. Too thin a wall thickness may cause collapse or wrinkling under the clamping force of the Y valve 330, disrupting the smoothness of the internal passage; while too thick a wall thickness will increase the overall rigidity, making it difficult to pass through the curved Y valve passage, and will reduce the deformation efficiency of the Y valve sealing ring when pressure is applied, which may affect the sealing effect.

[0028] In terms of material selection, the pressure catheter sleeve 310 can be made of medical-grade, platinum-cured silicone rubber. The Shore A hardness of this material is precisely selected within the range of 40A. This hardness value endows the catheter sleeve with excellent elasticity and flexibility. When the screw cap of the Y valve 330 is tightened, its internal silicone sealing ring 331 transmits pressure to the outer surface of the catheter sleeve 310. The 40A hardness silicone rubber can undergo moderate radial compression deformation under this pressure, perfectly filling any tiny gaps between the sealing ring 331 and the outer wall of the catheter sleeve, thus forming a completely reliable fluid seal capable of withstanding arterial blood pressure (e.g., up to 200 mmHg) without any leakage. Simultaneously, this deformation is elastic; when the Y valve is loosened, the catheter sleeve can quickly return to its original shape. Furthermore, the selected material has excellent biocompatibility, conforming to ISO 10993 standards, ensuring that no adverse reactions are triggered during brief contact with the patient's bodily fluids.

[0029] To minimize the sliding friction of the pressure microcatheter 320 within its lumen, the inner wall surface of the pressure catheter sleeve 310 undergoes a special treatment. In a preferred embodiment, its inner wall may be coated with a covalently bonded hydrophilic polymer coating, such as polyvinylpyrrolidone (PVP). Upon contact with blood or saline solution, this coating rapidly absorbs moisture, forming a super-slippery, stable hydration layer on the inner wall surface. The presence of this hydration layer transforms the original solid-solid friction into liquid-solid friction with an extremely low viscosity coefficient. Testing has shown that, after coating, the coefficient of kinetic friction of the pressure microcatheter 320 sliding within the lumen of the catheter sleeve 310 can be reduced to below 0.05 (dimensionless). This means that the retraction drive unit 120 only needs to apply a very small force (e.g., less than 0.02 Newtons) to drive the microcatheter, a force far insufficient to produce any perceptible drag effect on the Y valve 330 and its connected guiding system.

[0030] For example, a microscopic calculation can be performed on this mechanical relationship. Assume the Y valve 330 is tightened, and the total clamping force applied to the catheter sleeve 310 is Fclamp = 2 Newtons (N). Since the sealing action occurs between the Y valve and the catheter sleeve, this force is completely consumed at the interface forming the seal. At this point, the retraction drive unit 120 only needs to overcome the frictional force Ffriction of the microcatheter 320 inside the catheter sleeve 310. According to the frictional force formula Ffriction = μ × FN, where μ is the coefficient of dynamic friction and FN is the normal force. Since the normal force FN between the microcatheter and the inner wall of the catheter sleeve is extremely small (mainly generated by the microcatheter's own bending elasticity and gravity, which can be approximated as less than 0.1 Newtons), and the coefficient of dynamic friction μ is 0.05 after coating treatment, the required retraction drive force Fpull = Ffriction ≈ 0.05 × 0.1 N = 0.005 N. This value is more than 200 times smaller than the direct friction force between the Y valve and the conduit that needs to be overcome in the traditional mode (which can be as high as 1-1.5 Newtons). It is this difference in magnitude that fundamentally solves the technical contradiction.

[0031] The core function of the retraction drive unit 120 is to provide stable linear motion. In one specific implementation, the power source of this unit is a two-phase hybrid stepper motor. This stepper motor has a step angle of 1.8 degrees and uses 1 / 32 microstep subdivision drive technology, achieving a theoretical single-step resolution of 1.8° / 32 = 0.05625°. The motor is connected to a C5-grade ball screw via a zero-backlash flexible coupling. The lead of the ball screw is designed to be 2 mm, meaning that for every full rotation of the motor, the connected linear slider advances 2 mm. Combined with the microstep drive, the theoretical linear displacement resolution of the system can reach (0.05625° / 360°) × 2 mm ≈ 0.0003125 mm, or 0.3125 micrometers. This ultra-high resolution ensures absolute smoothness of the retraction speed and extremely high accuracy of distance positioning. A gripper is integrated on the linear slider for securely holding the tail end of the pressure microcatheter 320.

[0032] The controller 130 is responsible for executing all control logic, signal processing, and data management. In terms of hardware, the controller 130 can be a high-performance microcontroller (MCU) based on an ARM Cortex-M4F core, with a clock frequency of up to 180 MHz, and a built-in floating-point unit (FPU) capable of efficiently executing various complex computational tasks. This MCU runs a real-time operating system (RTOS), such as FreeRTOS, which allocates different functions (such as motor control, data acquisition, and user interface response) to different tasks, ensuring the real-time performance of critical tasks through preemptive scheduling. The controller 130 communicates with the stepper motor driver through a set of pulse / direction signal interfaces. By outputting pulses of precise frequency and quantity, the controller 130 can precisely control the movement speed and displacement of the retraction drive unit 120.

[0033] S200: Preoperative preparation and system installation After the interventional procedure begins and the patient's guiding catheter has been placed, the operator performs the following preparatory steps.

[0034] S210: Installation of pressure conduit sleeve The operator removes the pressure catheter sheath 310 and pressure microcatheter 320 from the sterile packaging. First, the flexible tip of the pressure microcatheter 320 is inserted into the proximal opening of the pressure catheter sheath 310 (the end furthest from the operator) and exits from the distal opening (the end closest to the operator). The operator slowly pushes the entire body of the pressure microcatheter 320 through the pressure catheter sheath 310 until the tail connector of the microcatheter protrudes from the distal end of the sheath. At this point, the pressure catheter sheath 310 is fitted over most of its tail end.

[0035] S220: Insertion and sealing establishment via Y valve Subsequently, the operator inserts the tip of the pressure microcatheter 320, already fitted with a catheter sheath, into the guiding catheter through the straight-through port of the Y valve 330. Under X-ray fluoroscopy guidance, the pressure sensor portion of the tip is precisely positioned at the distal end of the target vessel segment (i.e., the starting point of retraction). After positioning, the operator begins to tighten the screw cap of the Y valve 330. As the screw cap tightens, the silicone sealing ring 331 inside the Y valve begins to be axially compressed and radially expanded, gradually pressing against the outer surface of the pressure catheter sheath 310 passing through it. The operator continues to tighten until significant resistance is felt, or, using a Y valve with torque limiting function, until it emits a "click" sound. For example, when a torque of 0.4 N·m is applied, the radial pressure generated by the silicone sealing ring 331 on the catheter sheath 310 can reach 0.5 MPa, sufficient to form a completely reliable hemodynamic seal between them that can withstand arterial hypertension.

[0036] S300: Continuous Uniform Speed ​​Retraction and Synchronous Data Acquisition S310: Retreat Parameter Setting and Activation Before executing a pullback, the operator sets the parameters for the pullback through the system's human-computer interaction interface (such as a touchscreen). These parameters mainly include the total pullback distance and the pullback speed.

[0037] For example, based on intraoperative angiography assessment, the operator sets the total retraction distance to 80.0 mm and the retraction speed to 1.0 mm / s. These parameters are sent and stored in the internal memory of the controller 130. Once everything is ready, the operator presses the "Start Retraction" virtual button on the human-machine interface or a physical retraction trigger button. This operation generates a start command, which is captured by the controller 130.

[0038] S320: Motor Control and Continuous Motion Execution Upon receiving the start command, the motion control task of the controller 130 immediately begins execution. Based on the set speed of 1.0 mm / s and the ball screw lead of 2 mm, the controller 130 calculates the target speed required by the motor as (1.0 mm / s) / (2 mm / rev) = 0.5 rpm (rev / s). Then, based on the motor's step angle of 1.8° and microstep subdivision of 1 / 32, the controller calculates the pulse frequency required by the driver as (0.5 rev / s) × (360° / rev) / (1.8° / step) × 32 microsteps / step = 3200 Hz. The hardware timer inside the controller 130 is configured to precisely generate pulse signals at a frequency of 3200 Hz and send them to the motor driver. Simultaneously, the direction signal is set to the "retract" direction. After receiving the signal, the motor driver drives the stepper motor to rotate smoothly at the calculated precise speed, which in turn drives the linear slider and the pressure microcatheter 320 clamped on it through the ball screw to start continuous retraction at a constant speed of 1.0 mm / s.

[0039] S330: Synchronous Data Acquisition and Curve Generation At the same moment that the controller 130 issues the first motion control pulse, its data acquisition task is also activated. This task communicates with the external physiological signal acquisition module 110 via a high-speed serial interface (such as SPI or UART). The physiological signal acquisition module 110 continuously acquires analog pressure signals from the connector of the pressure microcatheter 320, and obtains digitized pressure readings after amplification, filtering, and analog-to-digital conversion (ADC). The controller 130 sends data request commands to the physiological signal acquisition module 110 at a fixed rate much higher than the frequency required for the pullback spatial resolution (e.g., every 10 milliseconds, or 100 Hz). Each time a request is received, the module 110 returns the current pressure value.

[0040] For example, at time t = 5.00 seconds, the pullback distance is 5.00 s 1.0 mm / s = 5.0 mm. At this moment, controller 130 requests data from module 110 and obtains a pressure reading of P = 92.5 mmHg. Controller 130 stores this pair of data (distance, pressure) as a data point (5.0, 92.5) in an array in memory.

[0041] At time t = 5.01 seconds, the retraction distance is 5.01 mm. Controller 130 requests data again and obtains a pressure reading of P = 92.4 mmHg. Controller 130 stores the data point (5.01, 92.4) into an array.

[0042] This process continues until the cumulative retraction distance reaches the preset total retraction distance of 80.0 mm. At this point, the controller 130 stops sending pulses, the motor stops rotating, and the retraction ends. The data point array in memory then forms a high-density, high-precision original pressure-distance retraction curve.

[0043] In a more preferred embodiment, the system also has the ability to fuse functional data with anatomical structures. (See also...) Figure 4 The system has added an image interface module 140 and a 3D reconstruction and fusion module 150.

[0044] Before performing the retraction, the operator has obtained at least two DICOM format angiographic images of the target vessel segment at different projection angles (e.g., RAO 30° and LAO 60°) using standard angiography procedures.

[0045] The image interface module 140 retrieves the two images from the hospital's Picture Archiving and Communication System (PACS). The 3D reconstruction and fusion module 150 first parses the image headers to extract imaging geometric parameters. Subsequently, using a model-based segmentation algorithm, it extracts the centerline and edge contours of the blood vessels from the 2D images. Utilizing the geometric constraints of dual-plane imaging and the epipolar principle, module 150 matches and triangulates the two 2D centerlines to reconstruct the coordinate point cloud of the blood vessel centerline in 3D space. By fitting spline curves to the point cloud, a smooth 3D centerline representing the blood vessel path is generated.

[0046] After step S300 generates the pressure-distance pullback curve, controller 130 sends the curve data to the 3D reconstruction and fusion module 150. Module 150 performs a mapping operation. It aligns and scales the one-dimensional pullback distance coordinate system (from 0 to 80.0 mm) with the arc length coordinate system of the 3D vessel centerline. Then, for each data point (L, P) on the pressure-distance curve, module 150 finds the position point with arc length L on the 3D centerline and obtains its 3D coordinates (x, y, z). Simultaneously, it looks up the corresponding color value from a preset color look-up table (CLUT) based on the pressure value P. For example, high pressure (>90 mmHg) corresponds to blue, medium pressure (70-89 mmHg) corresponds to green to yellow, and low pressure (<70 mmHg) corresponds to red. Ultimately, module 150 renders color-coded pressure information onto a three-dimensional vascular model on the human-computer interaction interface, forming an intuitive three-dimensional pressure gradient map, providing clinicians with a decision-making basis that integrates functional and anatomical factors. Example

[0047] It should be understood that the above embodiment 1 details the preferred solution proposed by the present invention to resolve the contradiction between Y-valve sealing and catheter movement. However, the concept of the present invention can also be used to address different technical challenges. In another implementation scenario, to solve the artifact problem caused by the heart's own movement on pressure measurement, this application also provides a step-by-step withdrawal system and method based on physiological signal gating, the specific structure and working principle of which are described below: This embodiment provides an electrically retractable system for intravascular functional assessment. This system is the physical carrier for implementing the method described in this embodiment. Referring to Figure 1, the system 100 includes: The physiological signal acquisition module 110 is configured to acquire physiological signals synchronized with the patient's cardiac cycle. The module hardware may include a multi-channel analog front-end capable of selecting different input channels via configurable jumpers or software switches to accommodate different physiological signal sources. The module firmware may include a library of preprocessing algorithms for different signal types. For example, when the user selects the IAP signal as the gating source, the controller 130 loads a descending isthmus (a morphological marker in the arterial blood pressure waveform appearing at the junction of systole and diastole, formed by the backflow of blood when the aortic valve closes) recognition algorithm, analyzing the waveform morphology by calculating the first and second derivatives of the blood pressure signal. The descending isthmus is characterized by a local minimum of the first derivative and a zero crossing of the second derivative; the algorithm generates a gating trigger event by detecting this combination of features.

[0048] In some embodiments, the physiological signal acquisition module 110 may include a preamplifier circuit and a signal conditioning circuit. The preamplifier circuit is configured to have a common-mode rejection ratio (CMRR) of not less than 100 dB to suppress common-mode noise. The signal conditioning circuit includes a notch filter and a bandpass filter. The notch filter is configured as a second-order IIR (Infinite Impulse Response) digital filter with a center frequency of 50 Hz to filter out power grid interference. The bandpass filter is configured as a fourth-order Butterworth bandpass filter with its -3 dB cutoff frequencies set at 0.5 Hz and 45 Hz to filter out baseline drift and high-frequency electromyographic noise while retaining key ECG components such as the QRS complex.

[0049] The retraction drive unit 120 is configured to clamp and linearly move a pressure microcatheter. Exemplarily, the power component of the retraction drive unit 120 can be a two-phase hybrid stepper motor with high torque density and low vibration characteristics. This motor is connected via a coupling to a precision-ground C5-grade ball screw, the nut portion of which is integrated with a linear slider to ensure high-precision linear transmission. In the embodiments described below, a gripper is mounted on this linear slider. The gripper uses a built-in piezoelectric ceramic force sensor to provide feedback on the clamping force, achieving closed-loop force control.

[0050] Controller 130 is configured to connect to the physiological signal acquisition module 110 and the retraction drive unit 120, and execute the core control logic of the method of the present invention. Exemplarily, controller 130 can be a microcontroller (MCU) based on an ARM Cortex-M7 core. Controller 130 runs a real-time operating system, allocating functions such as signal processing, motion control, data management, and user interface to different tasks to ensure the real-time performance and stability of the system response. Controller 130 receives data from the physiological signal acquisition module 110 through a high-speed SPI interface, controls the motor driver of the retraction drive unit 120 through a pulse / direction signal interface, and communicates with an external pressure measurement system through an isolated UART interface to send trigger commands and receive pressure data.

[0051] In one embodiment, the operator places the distal end of a pressure microcatheter into a clamping device equipped with a retraction drive unit and triggers a closing command on the clamp. A torque sensor inside the clamp monitors the clamping force in real time. When a preset force value (e.g., 0.5 Newtons) is reached—sufficient to prevent catheter slippage but below its damage threshold—the clamping action stops. The input interface of the physiological signal acquisition module is connected to the analog signal output port of a multi-parameter monitor. The operator selects the physiological signal gating source for this operation from a preset list via a human-machine interface. This list may include options such as "electrocardiogram (ECG) signal," "invasive arterial blood pressure (IAP) signal," and "cardiac sound (PCG) signal." In a specific scenario of this embodiment, the operator selects "electrocardiogram (ECG) signal."

[0052] The operator can set a series of control parameters to define the behavior of the pullback process through the human-computer interface. These control parameters constitute a parameter set, which includes a preset total pullback distance, a preset step size, and a gating delay time. The preset total pullback distance defines the linear range of the pullback operation, and its value can be set according to the length of the vessel segment to be evaluated. The preset step size defines the displacement of each discrete pullback action, and its value determines the spatial sampling density of the final generated pressure-distance curve. The gating delay time is a timing parameter used to locate a specific phase in the cardiac cycle.

[0053] For example, the operator sets the preset total pullback distance to 70.0 mm and the preset step size to 0.2 mm using the digital input controls on the touchscreen. This setting means that 70.0 / 0.2 = 350 discrete pressure sampling points will be generated throughout the pullback process. In some embodiments, the gating delay time can be automatically calculated and recommended by the system based on the real-time monitored patient heart rate, providing an initial gating delay time value. For example, if the system detects an average patient heart rate of 80 beats per minute, i.e., a cardiac cycle of 750 milliseconds (ms), the system can recommend a delay time between 40% and 50% of the cardiac cycle, i.e., 300 to 375 milliseconds. The operator can accept this recommended value or manually set it to a specific value, such as 320 milliseconds (ms), based on experience / needs. All set parameters can be stored in the non-volatile memory of the controller 130.

[0054] In one embodiment, refer to Figure 6 The method includes: S100: Real-time acquisition of physiological signals synchronized with the patient's heart cycle; and based on the physiological signals, identification of gating trigger events that characterize a preset physiological phase in the heart cycle.

[0055] S110: The physiological signal acquisition module 110 acquires simulated physiological signals from the multi-parameter monitor. When the gated source is set to an ECG signal, the signal acquired by the physiological signal acquisition module 110 is a multi-lead electrocardiogram waveform representing cardiac electrical activity. In the physiological signal acquisition module 110, the simulated signal first enters the preamplifier circuit to suppress common-mode noise. The amplified signal is input to the signal conditioning circuit, where the notch filter removes power grid interference, and the bandpass filter removes baseline drift and high-frequency electromyographic noise, while retaining the main electrocardiographic components such as the QRS complex.

[0056] S120: The conditioned analog signal is digitized by an analog-to-digital converter (ADC) to generate a continuous stream of digital signal samples. This digital signal sample stream is sent to the controller 130 for processing in real time.

[0057] S130: The controller 130 internally runs a gating event recognition algorithm to identify the gating trigger event from the digital signal sample stream. In this embodiment, the algorithm is configured as an R-wave detection algorithm. The R-wave detection algorithm can be implemented based on an improved Pan-Tompkins algorithm logic. Specifically, the algorithm sequentially performs differential, squaring, and moving window integration operations on the input signal sample stream to generate a feature signal. The differential operation highlights the steep slope of the QRS complex; the squaring operation enhances the amplitude of the signal and makes it non-negative; the moving window integration operation smooths the signal and forms a well-defined peak. The algorithm simultaneously maintains two dynamic thresholds: a signal threshold and a noise threshold. When a peak in the feature signal exceeds the signal threshold, and the time interval between its position and the previously detected R wave is within a physiologically reasonable range (e.g., for a heart rate range of 40 to 180 beats per minute, this interval is 333 milliseconds to 1500 milliseconds), the peak is identified as an R-wave. The moment the R-wave is confirmed, the controller generates a gating trigger event and records the timestamp of the event.

[0058] For example, the algorithm performs a first-order difference operation on the bandpass-filtered signal sample stream x(n) of S120 to obtain the slope signal. This operation can be performed using a transfer function. A finite impulse response (FIR) filter is used to highlight the steep rising and falling edges of the QRS group. For the slope signal... Each sample is squared point by point to generate an energy signal. This nonlinear transformation ensures that all signal values ​​are non-negative and significantly amplifies the energy of the high-frequency QRS group relative to the lower-frequency P-waves and T-waves. For the energy signal... Perform a moving window integration operation. This operation is achieved by summing the signal samples within a fixed-width window to generate a smooth feature signal. For example, at a sampling rate of 1000 Hz, an integration window with a width of 150 samples (corresponding to 150 milliseconds) can be used. This step integrates the energy of the QRS group into a single, broad peak, facilitating subsequent peak detection.

[0059] The algorithm employs a dual-threshold decision logic to identify the feature signal. The effective peak in the signal. The algorithm maintains two dynamic thresholds in real time: signal level threshold. and noise level threshold During the algorithm initialization phase, It was set to 50% of the maximum peak value calculated from the initial few seconds of data. It is set to 50% of the average signal amplitude. During operation, when... A new peak was detected in At that time, if If the peak value is not found, it is initially identified as a QRS candidate peak. If the time interval between this candidate peak and the previously confirmed R wave is greater than one physiological refractory period, then the candidate peak is confirmed as a valid R wave. After confirmation, the algorithm can update the threshold according to the following rules: (Previous value), where a and b are weighting coefficients. Understandably, these weighting coefficients can be set by those skilled in the art based on experience or needs, such as a=0.125, b=0.875. Then a similar weighted average update can be performed using the average amplitude of the segments not identified as signal peaks. If Between and In such cases, further judgment is needed by combining information such as the RR interval. If the peak value is not positive, it is ignored. This adaptive mechanism allows the algorithm to cope with changes in signal amplitude and baseline drift. When a valid R-wave is confirmed, the controller generates a gating trigger event.

[0060] S200: In response to each of the gated trigger events, control a retraction drive unit to drive a pressure microcatheter to perform a discrete retraction action with a preset step size; and during the rest period after each retraction action is completed, collect the pressure signal output by the pressure microcatheter, and associate the pressure signal with a corresponding current cumulative retraction distance to generate a pressure-distance data point.

[0061] Reference Figure 5This diagram illustrates a gating pullback timing relationship based on electrocardiogram (ECG) signals. The diagram uses time as the horizontal axis, schematically showing the ECG signal waveform, the triggering and duration of the gating delay, and the actions and data acquisition moments of the pullback drive unit from top to bottom. In the top ECG signal diagram, the periodically occurring waveform with the highest amplitude is the R wave, a marker of ventricular depolarization, which is used in this invention as a stable and reliable gating trigger event. In the middle gating delay diagram, whenever the system detects an R wave, a preset "gating delay time" is initiated. During this delay, the system remains silent, waiting for the heart to pass through the intense systolic phase. In the bottom pullback action diagram, after the gating delay ends, the pullback drive unit immediately performs a brief, step-by-step "pullback action" (represented by a thick black line). Immediately after the pullback action is completed, the system performs a "data acquisition" (represented by a hollow dot). This precise timing control ensures that each data acquisition occurs during the weakest end-diastolic phase of the heart's motion, thus achieving the core objective of this invention.

[0062] S210: After a gating trigger event is generated in S130, the controller starts an internal hardware timer and loads the gating delay time (e.g., 320 milliseconds) set in S100 into the timer. During the 320 milliseconds of the timer count, the pullback drive unit remains absolutely still.

[0063] S220: When the hardware timer counts to 320 milliseconds and generates an interrupt signal, the controller responds to this interrupt by sending a set of motion control commands to the motor controller of the retraction drive unit. The motion control commands include the target displacement (i.e., a preset step size of 0.2 mm) and motion speed / acceleration parameters. Based on the commands, the motor controller calculates the number of pulses and frequency curve required to drive the connected high-precision stepper motor. For example, for a system with a step angle of 0.9 degrees, using 1 / 16 microstep subdivision, and connected to a ball screw with a lead of 1 mm, moving 0.2 mm requires (0.2 / 1) × 200 × 16 = 640 pulses. The motor controller outputs these 640 pulses with an S-shaped acceleration / deceleration curve to ensure smooth start and stop, with the entire motion process completed within 50 milliseconds.

[0064] S230: After the motor controller confirms the completion of the movement and puts the motor into a locked state, the controller sends a high-level trigger pulse to an external pressure measurement system through one of its digital output pins. The pressure measurement system is configured to trigger a pressure data sampling on the rising edge of this pulse. Since the relative motion between the catheter sensor, the blood vessel (in end-diastole), and the drive device is minimal at this time, the sampled pressure value has a high signal-to-noise ratio.

[0065] S240: The controller maintains a current cumulative pullback distance variable in an internal register. After each successful step pullback, the controller adds a preset step size (0.2 mm) to this variable. Simultaneously, the controller 130 reads the pressure value (e.g., 88.3 mmHg) that was just triggered for sampling from the pressure measurement system. The updated current cumulative pullback distance and the read pressure value are stored as a data pair in a pre-allocated array of data points in system memory.

[0066] For example, assume that the current cumulative pullback distance is 0.0 mm before the pullback begins.

[0067] After the first R-wave is detected, the system performs the first 0.2 mm retraction after a 320 ms delay. Upon completion of the movement, the current cumulative retraction distance is updated to 0.2 mm. The system triggers pressure acquisition, obtaining a pressure value P1 = 90.1 mmHg. The controller stores the data points (0.2, 90.1) in memory.

[0068] After the second R-wave is detected, and after a 320-millisecond delay, the system performs a second 0.2 mm retraction. Upon completion of the movement, the current cumulative retraction distance is updated to 0.4 mm. The system triggers pressure acquisition, obtaining a pressure value P2 = 90.0 mmHg. The controller stores the data points (0.4, 90.0) in memory.

[0069] This process continues. Assume that after the 150th R-wave is detected, the system performs its 150th pullback. The current cumulative pullback distance is updated to 150 * 0.2 = 30.0 mm. At this point, the pressure microcatheter sensor enters the entrance of a narrow lesion. The system triggers pressure acquisition, obtaining a pressure value P150 = 72.5 mmHg. The controller stores the data point (30.0, 72.5). Thus, a clear pressure step caused by the lesion is accurately recorded, and its spatial location is precisely determined at 30.0 mm.

[0070] S300: Repeat the steps of controlling the retraction action, collecting pressure signals and performing correlation until the current cumulative retraction distance reaches a preset total retraction distance, so as to obtain a pressure retraction curve based on the generated multiple pressure-distance data points.

[0071] S310: After generating and storing a data point in S240, the controller 130 performs a conditional judgment. The value of the current cumulative pullback distance variable is compared with the preset total pullback distance (e.g., 70.0 mm).

[0072] S320: If the comparison result is that the current cumulative retreat distance is less than the preset total retreat distance, the controller ends the current loop and returns to the initial state of S100, that is, continues to listen to physiological signals and waits for the next gating trigger event to start the next delay-movement-acquisition-association loop.

[0073] S330: If the comparison result shows that the current cumulative pullback distance is greater than or equal to the preset total pullback distance, then the controller 130 determines that the entire pullback task is complete. The controller 130 will stop responding to new gating trigger events and send a final stop command to the pullback drive unit to ensure that it remains in its current position. At the same time, the controller 130 can display the pullback completion information through the human-machine interface.

[0074] S340: After the task is completed, the controller 130 accesses the data point array in memory and renders all the stored data points (350 in this example) graphically on the human-machine interface display screen in ascending order of pullback distance, generating a pressure pullback curve with distance (mm) on the x-axis and pressure (mmHg) on ​​the y-axis. Due to its data acquisition gating characteristics, this curve exhibits extremely low noise levels and clear pressure steps, providing reliable data support for clinical diagnosis.

[0075] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit described above can be implemented in hardware.

[0076] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An electrically driven reflux system for intravascular functional assessment, characterized in that, include: A retraction drive unit is configured to clamp and drive a pressure microcatheter to move linearly; A controller is connected to the retraction drive unit; A pressure catheter sleeve, which is a hollow tubular structure, is sleeved on the tail end of the pressure microcatheter; the material and size of the pressure catheter sleeve are configured such that when clamped by an interventional surgical Y valve, a fluid seal can be formed between the outer surface of the pressure catheter sleeve and the sealing structure of the Y valve, while allowing the pressure microcatheter to slide axially within the inner cavity of the pressure catheter sleeve. The controller is configured as follows: In response to a start command, the retraction drive unit is controlled to drive the pressure microcatheter to perform a retraction action at a preset speed; During the retraction action, the pressure signal associated with the pressure microcatheter and the corresponding retraction distance data are acquired simultaneously to generate a pressure-distance retraction curve.

2. The system according to claim 1, characterized in that, The pressure conduit sleeve is made of an elastic polymer material.

3. The system according to claim 2, characterized in that, The elastic polymer material is medical-grade silicone rubber or thermoplastic elastomer.

4. The system according to claim 1, characterized in that, The inner wall of the pressure conduit sleeve has a low-friction coating.

5. The system according to claim 1, characterized in that, The system also includes a human-computer interaction interface, on which a reversal trigger button is provided, and the start command is generated by an operation of the reversal trigger button.

6. The system according to claim 1, characterized in that, Also includes: An image interface module is configured to acquire at least two angiographic images from a angiography device at different projection angles. The controller is also configured to: Based on the at least two angiographic images, a three-dimensional anatomical model of a target vascular segment is reconstructed. The pressure-distance data points in the generated pressure-distance retreat curve are mapped to a set of corresponding three-dimensional spatial coordinate points on the three-dimensional anatomical model. Based on the mapping results, a visualized three-dimensional pressure gradient map is generated on the three-dimensional anatomical model.

7. The system according to claim 1, characterized in that, The system also includes: A physiological signal acquisition module is configured to acquire physiological signals synchronized with the patient's heart cycle; The controller is also configured to execute a gated step-back mode, in which the controller is configured to: Based on the physiological signals acquired by the physiological signal acquisition module, a gated trigger event that characterizes a preset physiological phase in the cardiac cycle is identified. In response to each of the gated trigger events, the retraction drive unit is controlled to perform a discrete retraction action with a preset step size; And during the rest period after each discrete pullback action is completed, the pressure signal is acquired.

8. The system according to claim 9, characterized in that, The physiological signal is an electrocardiogram (ECG) signal, and the gating trigger event is the R wave in the ECG signal.

9. A method for electrically withdrawing energy for intravascular functional assessment, characterized in that, include: Provide an electric retraction system as described in any one of claims 1 to 8; The pressure microcatheter fitted with the pressure catheter sheath is inserted into a target blood vessel via a Y valve. Tighten the Y valve so that the sealing structure of the Y valve is clamped on the outer surface of the pressure conduit sleeve, thereby forming a fluid seal; The start command is sent to the controller; In response to the start command, the retraction drive unit drives the pressure microcatheter to perform the retraction action at the preset speed, wherein the pressure microcatheter slides within the inner cavity of the pressure catheter sleeve; While the pressure microcatheter is being retracted, pressure signals and retraction distance data are simultaneously acquired to generate a pressure-distance retraction curve.

10. The method according to claim 9, characterized in that, The method further includes: Before or during the retraction action, acquire at least two angiographic images of the target vascular segment from different projection angles. Based on the at least two angiographic images, a three-dimensional anatomical model of the target vascular segment is reconstructed. The generated pressure-distance pullback curve is mapped onto the three-dimensional anatomical model to generate a visualized three-dimensional pressure gradient map.

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