A compound eye laser ablation catheter and laser ablation device

Abstract

This utility model relates to an ablation catheter in an in vivo laser ablation system, specifically a compound eye laser ablation catheter and laser ablation device. To address the shortcomings of existing laser ablation technologies, such as the inability to quantitatively control the amount of saline solution used for cooling, which can easily cause local vascular damage during ablation, or the reduction in laser transmission efficiency and energy due to imaging devices placed at the catheter tip, and poor imaging monitoring affecting the ablation effect, this utility model's compound eye laser ablation catheter includes a catheter body, which includes a catheter lumen, a light-transmitting fiber layer, and a catheter sheath. The light-transmitting fiber layer includes multiple light-transmitting fibers and a thermally conductive layer filling the spaces between the fibers. A guidewire and a temperature sensor are disposed within the catheter lumen. An imaging module is disposed on the catheter sheath, and the imaging module includes at least two compound eye imaging components. These components are used to perform real-time imaging of the ablation site and transmit the images to the outside.

Description

Technical Field

[0001] This utility model relates to an ablation catheter in an in vivo laser ablation system, specifically to a compound eye laser ablation catheter and laser ablation device. Background Technology

[0002] Cardiovascular disease is a major threat to human health worldwide. Atherosclerosis is a chronic, progressive, systemic vascular disease that primarily affects large and medium-sized arteries, such as the aorta, coronary arteries, lower limb arteries, and cerebral arteries. Atherosclerosis spreads throughout the body's blood vessels, causing vascular stenosis and inducing critical illnesses such as acute myocardial infarction, acute stroke, and peripheral tissue ischemia. Its high incidence, high disability rate, high mortality rate, and poor prognosis place a heavy burden on patients, families, and society. Currently, the mainstream treatments for this chronic disease include drug therapy, mechanical thrombectomy, ultrasonic thrombolysis, stent implantation, and laser ablation. Compared with traditional treatment methods, laser ablation has advantages such as smaller surgical incisions, shorter postoperative recovery time, high repeatability, and high precision. Because ultraviolet lasers have short wavelengths and high absorption rates in tissues, and primarily rely on the extremely high peak power of pulsed lasers to generate a micro-explosion effect on biological tissues for ablation, the heat generated by interaction with the tissue is minimal. This significantly reduces the damage to surrounding tissues caused by thermal diffusion. Therefore, ablation technology can effectively ablate thrombi and plaques within blood vessels through photochemical, photothermal, and photomechanical effects. However, currently, surgeons typically rely on surgical experience to apply saline solution for cooling during the procedure, which lacks quantitative control and can easily cause local vascular damage during ablation. Traditional imaging methods, such as OCT and ultrasound imaging, can only place imaging devices at the tip of the catheter, leading to reduced laser transmission efficiency and energy. Furthermore, the water vapor and tissue debris generated during ablation affect the imaging at the tip, resulting in poor imaging monitoring and thus impacting the ablation effect. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of existing laser ablation technologies, such as the inability to quantitatively control the amount of saline solution used for cooling, which can easily cause local vascular damage during ablation, or the reduction in laser transmission efficiency and energy due to the imaging device placed at the tip of the catheter, as well as the poor imaging monitoring effect that affects the ablation effect. Therefore, this invention provides a compound eye laser ablation catheter and laser ablation device.

[0004] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0005] A compound eye laser ablation catheter includes a catheter body comprising a guidewire, a light-transmitting fiber layer, and a catheter sheath disposed outside the light-transmitting fiber layer. The light-transmitting fiber layer is used to transmit pulsed laser light. A catheter lumen for injecting physiological saline is disposed along the central axis of the light-transmitting fiber layer. The guidewire is disposed on the central axis of the catheter lumen. The catheter is characterized by further including M temperature sensors and an imaging module, where M ≥ 2. The light-transmitting fiber layer includes multiple light-transmitting fibers and a thermally conductive layer filling the spaces between the fibers. The distal end of the thermally conductive layer is used to interface with a cold surface for heat conduction. The probes of the M temperature sensors are located at the ablation end of the catheter body and are uniformly disposed within the catheter lumen along the circumference of the guidewire. The imaging module is disposed on the catheter sheath and close to the ablation end of the catheter body, and includes at least two compound eye imaging components uniformly disposed along the circumference of the catheter sheath. The compound eye imaging components are used to perform real-time imaging of the ablation area and transmit the image to the outside.

[0006] Furthermore, the compound eye imaging assembly includes a compound eye lens disposed on the sidewall of the duct capsule and a detector disposed on the corresponding compound eye lens. The compound eye lens is a microlens array disposed along the arc surface, and the microlens array includes multiple microlenses arranged in a hexagonal honeycomb structure.

[0007] By definition, each of the microlenses and its six neighboring microlenses constitute a monitoring unit, and each monitoring unit's microlenses are configured with different operating wavelengths.

[0008] Furthermore, the number N of the optical fibers is calculated using the following formula:

[0009]

[0010] Where, r o r is the outer radius of the optical fiber layer. i r is the radius of the catheter lumen. f β is the radius of the optical fiber, and β is the fiber fill factor.

[0011] Furthermore, the ablation end of the optical fiber layer is provided with a protective glass cover;

[0012] The thermally conductive layer is composed of thermally conductive potting compound injected into the gap between adjacent optical fibers.

[0013] The temperature sensor is a miniature thin-film temperature sensor;

[0014] The plurality of optical fibers are arranged concentrically around the central axis, with a fiber fill factor of 75.7%; or the plurality of optical fibers are arranged in hexagonal layers from the inside out around the central axis, with a fiber fill factor of 90.69%.

[0015] A laser ablation device is characterized by comprising a laser source system, an intelligent temperature control system, the aforementioned compound eye laser ablation catheter, and an imaging data processing system. The output end of the laser source system is connected to the compound eye laser ablation catheter to provide a laser source. The intelligent temperature control system is connected to both the temperature sensor and the laser source system, and dynamically adjusts the output power and repetition frequency of the laser source system based on temperature data monitored by the temperature sensor. The input end of the imaging data processing system is connected to the output end of the imaging module, and receives and processes the image formed by the imaging module, controlling the output power and repetition frequency of the laser source system based on the processing results, while simultaneously identifying the corresponding region.

[0016] Furthermore, the compound eye imaging assembly includes a compound eye lens and a detector disposed on the sidewall of the duct capsule. The compound eye lens is a microlens array disposed along the arc surface, and the microlens array includes multiple microlenses arranged in a hexagonal honeycomb structure.

[0017] By definition, each of the microlenses and the six microlenses in its neighborhood constitute a monitoring unit, and the microlenses of each monitoring unit are respectively set with different working wavelengths to achieve large field-of-view multispectral compound eye imaging;

[0018] The detector is set to correspond to the compound lens and is used to detect multispectral images and transmit the multispectral images of the ablation site to the imaging data processing system wirelessly.

[0019] The imaging data processing system performs spectrochemical analysis on the composition of the ablation zone based on the multispectral images.

[0020] The beneficial effects of this utility model are:

[0021] 1. The compound eye imaging component in the compound eye laser ablation catheter of this utility model is set on the side wall of the catheter capsule. Through compound eye imaging, a large-scale real-time image of the blood vessel wall can be directly monitored. The observation range is large and the radial area of ​​the catheter body is reduced. At the same time, it does not affect the cross-sectional area of ​​the optical fiber layer, ensuring light transmission efficiency and energy. Setting it on the side wall of the catheter capsule also avoids the water vapor and tissue debris generated during the laser ablation process from affecting the imaging effect.

[0022] 2. In this invention, the gaps in the optical fibers of the compound eye laser ablation catheter are filled with thermally conductive potting compound as a thermally conductive layer. This effectively and uniformly reduces the temperature of the ablation site. Since the ablation site is ablated by the laser energy of each optical fiber, and the gaps between each adjacent optical fiber are thermally conductive and can be adjusted in real time according to the temperature of the external cold surface, uniform temperature control of the ablation site is achieved. This keeps the temperature inside the blood vessel within a safe range to eliminate damage to the blood vessel and solves problems such as uncontrollable temperature of the ablation site and damage to the blood vessel.

[0023] 3. The compound eye laser ablation catheter of this utility model integrates a light transmission fiber with controllable ablation end temperature, a compound eye imaging component, a temperature sensor and a guidewire. When combined, they work together to solve problems such as uncontrollable temperature of the ablation section, uncontrollable ablation efficiency of different plaque components and difficulty in detecting vascular damage.

[0024] 4. This novel laser ablation device, through a temperature sensor and intelligent temperature control system installed within the catheter lumen, can monitor the temperature of the ablation site in real time. This provides the operator with quantitative assessment and analysis of the time and energy required for plaque ablation, solving problems such as uncontrollable ablation efficiency for different plaque components. Simultaneously, this invention also includes an imaging data processing system to adjust the output power, repetition frequency, and saline injection rate of the laser source system based on the deviation of the spectral curve, further improving the accuracy of temperature and ablation efficiency control and avoiding tissue damage. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the cross-section of the ablation end of an embodiment of the compound eye laser ablation catheter of this utility model;

[0026] Figure 2 This is a cross-sectional view along the axis of an embodiment of the compound eye laser ablation catheter of this utility model;

[0027] Figure 3 This is a schematic diagram of the microlens array arrangement in an embodiment of the compound eye laser ablation catheter of this utility model;

[0028] Figure 4 This is a schematic diagram of an embodiment of the laser ablation device of this utility model.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1-Catheter lumen, 2-Guidewire, 3-Temperature sensor, 4-Optical fiber, 5-Heat-conducting layer, 6-Catheter sheath, 7-Compound eye imaging assembly, 8-Protective glass cover. Detailed Implementation

[0031] like Figure 1 and Figure 2As shown, this utility model of a compound eye laser ablation catheter includes a catheter body and a protective glass cover 8 disposed at the ablation end of the catheter body. It is used for ablation of blood vessels or other tissues. The catheter body includes a guidewire 2, M temperature sensors 3, a light-transmitting fiber layer, and a catheter sheath 6 disposed outside the light-transmitting fiber layer, wherein M ≥ 2. A catheter lumen 1 is disposed along the central axis of the light-transmitting fiber layer. The guidewire 2 is disposed on the central axis of the catheter lumen 1 to guide the catheter body to the lesion site in the blood vessel. An inner wall is formed on the inner sidewall of the light-transmitting fiber layer, which separates the light-transmitting fiber layer from the catheter lumen 1. The material of the catheter sheath 6 is not limited and can be further selected according to the surgical experimental environment and processing feasibility. Currently commonly used materials include TPU (thermoplastic polyurethane), PEBAX (polyether block amide), and PA (polyamide).

[0032] M temperature sensors 3 are located at the ablation end of the catheter body and are evenly arranged along the circumference of the guidewire 2 within the inner lumen 1 of the catheter, for real-time sensing of the temperature distribution in the ablation zone. In this embodiment, M=3, and the temperature sensors 3 are miniature thin-film temperature sensors.

[0033] The optical fiber layer comprises multiple optical fibers 4 and a thermally conductive layer 5 filling the spaces between them. The input ends of the optical fibers 4 are connected to an external laser source to transmit pulsed laser light in the ultraviolet band and deliver it to the ablation site with low loss. The thermally conductive layer 5 is composed of thermally conductive potting compound injected into the gaps between adjacent optical fibers 4, and its distal end is connected to a cold surface to achieve heat conduction, thereby reducing the temperature inside the blood vessel and in the ablation site. The lower the temperature of the cold surface, the better the thermal conductivity.

[0034] The catheter body of this invention is configured as a multi-layered structure arranged sequentially from the inside out. The guidewire 2 is located at the center of the catheter lumen 1, the lumen wall, and the catheter sheath 6. Temperature sensors are uniformly arranged circumferentially around the guidewire 2. Multiple optical fibers 4 are arranged concentrically, layer by layer around the lumen wall from the inside out, gradually expanding outwards. The number of fibers in each layer is determined according to the specific energy requirements of the ablation procedure. In other embodiments, the optical fibers 4 can also be arranged in a hexagonal layer around the lumen wall from the inside out. The outer contours of the six adjacent optical fibers 4 of each fiber form a hexagonal structure, and each optical fiber 4 is equidistant from the six adjacent fibers, further improving the energy density of the catheter beam and reducing energy crosstalk.

[0035] The light transmission fiber 4 is configured as a special high-damage-threshold multimode fiber. The number N of light transmission fibers 4 is determined according to the outer radius r of the light transmission fiber layer in the actual application. o Catheter inner lumen radius r i , radius r of optical fiber f The fiber filling factor β is determined and is specifically calculated using the following formula:

[0036]

[0037] The filling factor is obtained by calculating the ratio of the sum of the effective cross-sectional areas of the optical fibers 4 to the cross-sectional area of ​​the optical fiber layer. In this embodiment, multiple optical fibers 4 are arranged in concentric circles, and the fiber filling factor β can reach 75.7%. In other embodiments, when they are arranged in hexagonal layers from the inside out, the fiber filling factor β can reach 90.69%.

[0038] Based on the heat conduction formula, the heat transfer capacity Q of the thermally conductive potting compound can be calculated, as shown below:

[0039]

[0040] Where T1 is the temperature of the ablation zone, T2 is the temperature of the external cold surface, k is the thermal conductivity of the thermally conductive potting compound, S is the end face surface area of ​​the optical fiber slot, and L is the length of the potting compound.

[0041] During the cooling process, the temperature of the ablation site changes according to the temperature regulation of the external cold surface. In addition, physiological saline can be injected into the lumen 1 of the catheter simultaneously as a supplementary means of cooling the ablation site.

[0042] The protective glass cover 8 is set at the ablation end of the optical fiber layer. Its main purpose is to homogenize the output light field of the optical fiber 4, avoid uneven laser light field energy, and prevent tissue fragments from adhering to the ablation end of the optical fiber 4.

[0043] like Figure 2 As shown, the compound eye laser ablation catheter of this utility model also includes an imaging module for real-time imaging and monitoring of internal vascular damage and biochemical tissue status. The imaging module includes two compound eye imaging components 7 integrated on the side wall of the catheter capsule 6 and close to its ablation end. In this embodiment, the compound eye imaging component 7 is set as a compound eye multispectral imaging component. The two compound eye multispectral imaging components are evenly distributed along the circumference of the catheter capsule 6 and are located on both sides of the catheter capsule 6 respectively.

[0044] like Figure 3 As shown, the compound eye multispectral imaging component includes a compound eye lens and a detector. The compound eye lens is a microlens array arranged along the curved surface, consisting of multiple microlenses arranged in a hexagonal honeycomb structure. Each microlens in the microlens array and its six neighboring microlenses constitute a cluster eye as a monitoring unit. Each monitoring unit's microlens corresponds to a different working wavelength, denoted as λ1 to λ7. The spectral bands are transmitted through the cross-transmission of adjacent apertures of the compound eye to achieve large field-of-view multispectral compound eye imaging. The detector is set corresponding to the compound eye lens to detect the multispectral image and transmits the multispectral image of the ablated blood vessel to the outside via wireless transmission.

[0045] like Figure 4 As shown, when the aforementioned compound eye laser ablation catheter is applied to actual laser ablation surgery, it is used in conjunction with an intelligent temperature control system, a laser source system, and an imaging data processing system to form a laser ablation device. The output end of the laser source system is connected to the input end of the compound eye laser ablation catheter to provide the laser source. The imaging data processing system receives and processes the multispectral images transmitted by the detector and controls the output power and repetition frequency of the laser source system based on the processing results. This invention achieves large-scale real-time image visualization of the ablation site through compound eye imaging. The imaging data processing system performs spectrochemical analysis on the composition of the ablation site based on the multispectral images, including lipids, collagen, and hemoglobin, to monitor vascular damage. It can also analyze and identify areas with high lipid content, particularly lipid-core plaques associated with plaque rupture leading to heart attacks.

[0046] The intelligent temperature control system is connected to the temperature sensor 3 and the laser source control system by signal lines and electrical signals. The system dynamically adjusts the output power and repetition frequency of the laser source system based on the temperature data monitored by the temperature sensor 3.

[0047] The higher the output power of the laser source system, the larger its effective ablation area and the faster the ablation rate, but the more likely it is to cause vascular damage. A higher repetition frequency results in faster ablation, but also generates more large particles during the ablation process. Plaque fragments or detached thrombi from laser ablation can block distal microvessels, increasing the likelihood of vascular damage and no-reflow. Generally, the output power is determined by the ablation area, while the repetition frequency is determined by the type of plaque and the severity of the lesion.

[0048] The combination of laser output power and repetition frequency varies depending on the specific ablation situation. Taking atherosclerosis as an example, for ablation of soft plaques caused by thrombi, the repetition frequency is controlled to be in the low repetition rate range (i.e., less than or equal to 50% of the peak repetition rate) to reduce the number of large particles generated in the blood vessel after ablation. The laser output power is then selected based on the area of ​​the ablation plaque. When the ablation plaque area is greater than or equal to two-thirds of the catheter aperture, it can be considered a large thrombus. In this case, a high output power (greater than or equal to 75% of the peak output power) is used, while the repetition frequency is in the low repetition rate range to achieve the maximum effective ablation area. Conversely, when the ablation plaque area is of normal size, the effective ablation area required is correspondingly smaller. Therefore, the light source output mode is adjusted to a medium-low output power (i.e., 30%–70% of the peak output power), while the repetition frequency is in the low repetition rate range.

[0049] For high-resistance lesions such as calcified spots, high output power and high repetition rate range (i.e., greater than 50% of the peak repetition rate) are used to ensure that the ablation part is eroded by click and can pass through the lesion in a short time, avoiding heat accumulation and vascular damage.

[0050] After the laser ablation device is activated, the output power and repetition frequency of the laser source system are adjusted from low to high. At the beginning of ablation, the lowest output power and repetition frequency should be used, gradually increasing the output power to achieve effective ablation. During ablation, once the temperature sensor 3 and the multispectral compound eye monitoring module collect real-time data on vascular damage, the source output module will also make corresponding adjustments. It is important to note that the output power and repetition frequency adjustments should be in the same direction, i.e., simultaneously decreasing or increasing both output power and repetition frequency.

[0051] The temperature of the ablation site can be obtained in real time by temperature sensor 3. Since the common temperature of the ablation site and surrounding tissues during actual ablation surgery is around 50°C, when the temperature of the ablation site and surrounding tissues is 50-55°C, the output power is dynamically reduced to a lower level (i.e., the absolute peak power is reduced by 20%-30%) and the saline injection speed is increased. When the temperature of the ablation site and surrounding tissues is greater than 55°C, the repetition frequency is adjusted to 0, the pulsed laser output is immediately stopped, and saline is injected at the maximum injection speed to cool down.

[0052] Based on the information acquired by temperature sensor 3, this invention also introduces a method for adjusting the output power and repetition frequency of the laser source system based on multispectral images. The main technical principle is to collect the spectral information of the ablated tissue in real time through the compound eye multispectral imaging component at the ablation end, and control the output parameters of the source according to the corresponding spectral information. In the compound eye lens used in this invention, each monitoring unit can integrate a total of 7 filters of different wavelengths for the same area, which can simultaneously acquire the spectral information of 7 different spectral bands in the same area. After subsequent calculation and fitting, the real-time spectral curve of the corresponding area can be obtained. However, due to the changes in tissue composition after the blood vessel wall is ablated (such as hemoglobin denaturation and decreased water content), the corresponding spectral curve will show a significant deviation from the spectral curve of the same area when no ablation has occurred. When the deviation is within a reasonable range, the output power is dynamically reduced (i.e., the absolute peak power is reduced by 20%-30%), and the saline injection rate is increased. When the deviation of the curve significantly exceeds the reasonable threshold, the repetition frequency is adjusted to 0, the pulsed laser output is immediately stopped, and saline is injected at the maximum perfusion rate to cool down.

[0053] The above description is only a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model.

Claims

1. A compound eye laser ablation catheter, comprising a catheter body, the catheter body comprising a guidewire (2), a light-transmitting fiber layer, and a catheter cladding (6) disposed outside the light-transmitting fiber layer, the light-transmitting fiber layer being used to transmit pulsed laser light, and a catheter lumen (1) for injecting physiological saline being disposed along the central axis of the light-transmitting fiber layer, the guidewire (2) being disposed on the central axis of the catheter lumen (1); characterized in that: It also includes M temperature sensors (3) and an imaging module, where M≥2; The optical fiber layer includes multiple optical fibers (4) and a heat-conducting layer (5) filled between the optical fibers (4). The far end of the heat-conducting layer (5) is used to dock with a cold surface to achieve heat conduction. The probes of the M temperature sensors (3) are located at the ablation end of the catheter body and are evenly arranged in the inner lumen (1) of the catheter along the circumference of the guidewire (2); The imaging module is disposed on the catheter sheath (6) and close to the ablation end of the catheter body, and includes at least two compound eye imaging components (7) uniformly arranged along the circumference of the catheter sheath (6). The compound eye imaging components (7) are used to perform real-time imaging of the ablation part and transmit it to the outside.

2. The compound eye laser ablation catheter according to claim 1, characterized in that: The compound eye imaging component (7) includes a compound eye lens disposed on the side wall of the duct capsule (6) and a detector disposed on the corresponding compound eye lens. The compound eye lens is a microlens array disposed along the arc surface. The microlens array includes multiple microlenses arranged in a hexagonal honeycomb structure. By definition, each of the microlenses and its six neighboring microlenses constitute a monitoring unit, and each monitoring unit's microlenses are configured with different operating wavelengths.

3. The compound eye laser ablation catheter according to claim 1 or 2, characterized in that: The number N of the optical fibers (4) is calculated by the following formula: Where, r o r is the outer radius of the optical fiber layer. i r is the radius of the catheter lumen. f β is the radius of the optical fiber, and β is the fiber fill factor.

4. The compound eye laser ablation catheter according to claim 3, characterized in that: The ablation end of the optical fiber layer is provided with a protective glass cover (8); The thermally conductive layer (5) is composed of thermally conductive potting compound injected into the gap between adjacent optical fibers (4); The temperature sensor (3) is a miniature thin-film temperature sensor; The multiple optical fibers (4) are arranged concentrically around the central axis, with a fiber fill factor of 75.7%; or, the multiple optical fibers (4) are arranged in hexagonal layers from the inside to the outside around the central axis, with a fiber fill factor of 90.69%.

5. A laser ablation device, characterized in that: It includes a laser light source system, an intelligent temperature control system, the compound eye laser ablation catheter as described in claim 1, and an imaging data processing system; The output end of the laser source system is connected to the compound eye laser ablation catheter to provide a laser source; The intelligent temperature control system is connected to the temperature sensor (3) and the laser source system respectively, and is used to dynamically adjust the output power and repetition frequency of the laser source system according to the temperature data monitored by the temperature sensor (3); The input end of the imaging data processing system is connected to the output end of the imaging module, and is used to receive and process the image formed by the imaging module, and control the output power and repetition frequency of the laser source system according to the processing result, while identifying the corresponding area.

6. The laser ablation device according to claim 5, characterized in that: The compound eye imaging component (7) includes a compound eye lens and a detector disposed on the side wall of the duct capsule (6). The compound eye lens is a microlens array disposed along the arc surface. The microlens array includes multiple microlenses arranged in a hexagonal honeycomb structure. By definition, each of the microlenses and the six microlenses in its neighborhood constitute a monitoring unit, and the microlenses of each monitoring unit are respectively set with different working wavelengths to achieve large field-of-view multispectral compound eye imaging; The detector is set to correspond to the compound lens and is used to detect multispectral images and transmit the multispectral images of the ablation site to the imaging data processing system via wireless transmission. The imaging data processing system performs spectrochemical analysis on the composition of the ablation zone based on the multispectral images.

Images