Anti-reflux microcatheter for perfusion chemotherapy

Abstract

The application discloses an anti-reflux microcatheter for perfusion chemotherapy, and belongs to the field of interventional medical instruments, which comprises a main body tube, a catheter seat, a developing ring and a balloon structure. After injecting drugs through the main cavity, the occlusion area is expanded to adhere to the inner wall of the blood vessel and occlude the reflux gap between the microcatheter and the inner wall of the blood vessel. After the injection pressure continues to rise, the drugs are released to the distal end of the balloon structure through the drug release structure. The application effectively blocks the reflux of the chemotherapy drugs by the scheme of first occluding the gap between the microcatheter and the inner wall of the blood vessel and then releasing the drugs, reduces the damage of the drugs to the non-target tissues, realizes the directional perfusion of the drugs, significantly improves the chemotherapy effect, reduces the systemic toxic side effects and does not depend on the blood flow environment, and can still stably occlude under high-flow blood vessels. The balloon inflation and the drug liquid perfusion of the application share the same main cavity, an independent balloon inflation cavity is not needed, the overall outer diameter of the microcatheter can be reduced, the passability of the microcatheter in the ultrafine, tortuous and distal blood vessels can be improved, and the intraoperative operation is simplified.

Description

Technical Field

[0001] This invention relates to the field of interventional medical devices, and in particular to an anti-reflux microcatheter for perfusion chemotherapy. Background Technology

[0002] Transarterial infusion chemotherapy (TAIC) is an important minimally invasive treatment for liver cancer, pancreatic cancer, lung cancer, head and neck tumors, and pelvic malignancies. Its core treatment logic is to locally infuse chemotherapy drugs into the tumor via superselective tumor-feeding arteries, thereby increasing the local drug concentration in the tumor and reducing systemic toxic side effects.

[0003] Current mainstream clinical microcatheters have the following technical shortcomings: 1. Ordinary bare microcatheters lack anti-reflux structures. During chemotherapy drug injection, they are very prone to reflux along the gaps in the outer wall of the catheter under the impact of blood flow, causing drug damage to non-target tissues such as normal blood vessels, gastrointestinal tract, bile duct, and skin, which is a major source of clinical complications. At the same time, the drug is diluted by blood flow, resulting in low effective drug concentration at the tumor site and limited treatment effect.

[0004] 2. Existing fluid barrier-type anti-reflux microcatheters (such as the SeQure microcatheter) rely on side-hole jets to form a dynamic fluid barrier, without a mechanical sealing structure. This structure can only reduce reflux to a limited extent under low-to-medium velocity blood flow. In high-velocity vessels, in tumors with high blood supply, or in scenarios with turbulent blood flow in the mid-to-late stages of perfusion, the fluid barrier is easily broken down by the blood flow, and the drug reflux problem cannot be completely solved. Furthermore, the fluid barrier structure cannot block proximal blood flow flushing, and the drug dilution problem cannot be eradicated.

[0005] 3. Traditional clinical balloon occlusion microcatheters all adopt a dual-lumen independent structure: one lumen is for balloon filling and the other for drug delivery. This structure has drawbacks such as large catheter outer diameter, poor permeability, complex structure, cumbersome operation, high manufacturing cost, and the need for repeated channel switching during the procedure. It cannot be adapted to superselective chemotherapy scenarios involving ultra-thin, tortuous, and distal target vessels. Summary of the Invention

[0006] This invention provides an anti-reflux microcatheter for perfusion chemotherapy, which achieves balloon expansion and drug perfusion through a single-lumen structure, thereby solving the problems of proximal reflux that easily occurs during drug perfusion in existing microcatheters, as well as the large outer diameter and multiple operating channels of double-lumen balloon catheters.

[0007] An anti-reflux microcatheter for perfusion chemotherapy includes a main tube, a catheter seat, a contrast ring, and a balloon structure disposed at the distal end of the main tube. The main tube has a main lumen extending through it along its axis, and the balloon structure has a balloon cavity communicating with the main lumen. The balloon structure includes a blocking region and a drug release region. The drug release region is provided with a drug release structure. After drug is injected through the main lumen, the blocking region expands to conform to the inner wall of the blood vessel and seals the reflux gap between the microcatheter and the inner wall of the blood vessel. After the injection pressure continues to increase, the drug is released through the drug release structure to the distal end of the balloon structure.

[0008] Preferably, the balloon structure can be fully or partially contracted within the distal end of the main tube, and the radial dimension of the balloon structure in the uninflated state is smaller than the radial dimension of the main tube.

[0009] Preferably, the balloon structure is a single-layer balloon, with multiple drug-release structures located at the distal end of the balloon structure and distributed at intervals along the circumference or axial direction of the balloon structure.

[0010] Preferably, the inflation pressure of the balloon structure is 0.5 atm–1.5 atm, the release pressure of the drug release structure is 1.5 atm–3 atm, and the burst pressure of the balloon structure is not less than 4 atm.

[0011] Preferably, the drug release structure is an elastic slit, which remains closed when the pressure is below the preset drug release pressure and opens to release the drug when the preset drug release pressure is reached.

[0012] Preferably, the balloon structure folds circumferentially to form multiple folded flaps in the uninflated state, and the multiple folded flaps extend axially along the main tube and are distributed circumferentially around the main tube. During the inflation process, the multiple folded flaps unfold outward.

[0013] Preferably, the balloon structure includes an outer balloon and a closed inner balloon disposed within the outer balloon; The inner balloon has a predetermined rupture section, the thickness of which is less than the thickness of the rest of the inner balloon.

[0014] Preferably, the inner balloon is connected to the main lumen, and the outer balloon has a drug release structure. After the drug is injected into the main lumen, the inner balloon expands and causes the outer balloon to adhere to the inner wall of the blood vessel. The predetermined rupture part ruptures after the injection pressure reaches the preset rupture pressure, so that the main lumen is connected to the outer balloon, and the drug release structure completes the drug release.

[0015] Preferably, the inner balloon is a diaphragm located inside the outer balloon, which divides the outer balloon into a proximal cavity and a distal cavity. The proximal cavity is directly connected to the main lumen. After the outer balloon is injected with drugs through the main lumen, it expands to fit the inner wall of the blood vessel. The predetermined rupture section on the diaphragm ruptures after reaching a predetermined rupture pressure, so that the distal cavity is connected to the main lumen, and drug release is completed through the drug release structure.

[0016] Preferably, the predetermined rupture pressure of the predetermined rupture portion is 1.5 atm to 3 atm, and the burst pressure of the outer balloon is not less than 4 atm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention effectively blocks the backflow of chemotherapy drugs by first sealing the gap between the microcatheter and the inner wall of the blood vessel and then releasing the drug, thereby reducing or eliminating the damage of non-target tissue drugs to other parts of the body, achieving targeted drug perfusion, significantly improving the effect of chemotherapy, reducing systemic toxic side effects, and not depending on the blood flow environment. It can still stably seal the blood vessels even under high flow rate conditions. In this invention, balloon inflation and drug infusion share the same main lumen, eliminating the need for a separate balloon inflation chamber. This reduces the overall outer diameter of the microcatheter, improves its permeability in ultra-thin, tortuous, and distal blood vessels, and simplifies intraoperative procedures. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the balloon structure in the uninflated state of Example 1. Figure 2 This is a schematic diagram of the drug release structure; Figure 3 This is a schematic diagram of the overall structure of the balloon structure in the inflated state of Embodiment 1. Figure 4 This is a schematic diagram of the single-layer balloon structure in Example 1; Figure 5 This is a schematic diagram of the four-lobed, gripping, folded balloon structure of Example 2; Figure 6 This is a schematic diagram of the double-layer balloon structure in Example 3; Figure 7 This is a schematic diagram of the distal structure of the single-layer balloon in the incompletely inflated state in Example 1. Figure 8 This is a schematic diagram of the distal structure of the single-layer balloon after inflation, as shown in Example 1. Figure 9 This is a schematic diagram of the distal structure of the double-layered balloon in Example 3 before rupture at the predetermined rupture site; Figure 10 This is a schematic diagram of the distal structure of the double-layered balloon after rupture at the predetermined rupture point in Example 3; Figure 11A schematic diagram illustrating the use of an anti-reflux microcatheter for perfusion within a tumor-feeding artery. Figure 12 This is a schematic diagram of drug reflux into a branch artery during routine microcatheter infusion.

[0019] Explanation of reference numerals in the attached figures: 1-Microcatheter, 2-Catheter seat, 3-Main tube, 4-Illuminating ring, 5-Balloon structure, 5-1-Single-layer balloon, 5-2-Double-layer balloon, 6-Drug release structure, 7-Outer balloon, 8-Inner balloon, 9-Conventional microcatheter, 10-Tumor, 11-Tumor feeding artery, 12-Branch artery, 13-Chemotherapy drug, 14-Main lumen, 15-Occlusion area, 16-Drug release area, 17-Predicted rupture site. Detailed Implementation

[0020] The following detailed description of a specific embodiment of the present invention is provided in conjunction with the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0021] Example 1 like Figures 1 to 4 , Figure 7 and Figure 8 As shown, an anti-reflux microcatheter for perfusion chemotherapy provided by an embodiment of the present invention includes a catheter seat 2, a main tube 3, a contrast ring 4, and a balloon structure disposed at the distal end of the main tube 3; Among them, such as Figure 1 and Figure 3 As shown, the catheter seat 2 is located at the proximal end of the main tube 3 and is used to connect to a syringe, injection pump or other infusion device. The main tube 3 forms an axially penetrating main lumen 14. The proximal end of the main lumen 14 is connected to the catheter seat 2, and the distal end of the main lumen 14 is directly connected to the balloon cavity of the balloon structure 5. The imaging ring 4 is fixed at the distal end of the main tube 3 and located at the proximal end of the balloon structure 5, which makes it easier for doctors to determine the position of the balloon structure 5 under medical imaging. In some other embodiments, such as Figure 7 and Figure 8 As shown, the main tube 3 adopts a three-layer composite tube wall structure, including an inner layer, a middle reinforcing layer and an outer layer. The inner layer is used to form a low-friction inner wall, the middle reinforcing layer is used to improve the torsional resistance and flexural resistance of the main tube 3, and the outer layer is used to provide flexibility and biocompatibility. like Figure 4 As shown, the balloon structure 5 in this embodiment is a single-layer balloon 5-1. The single-layer balloon 5-1 includes a blocking area 15 near the main tube 3 and a drug release area 16. Multiple drug release structures 6 are provided at the distal end of the drug release area 16. The multiple drug release structures 6 can form an array along the circumference of the balloon or multiple rows along the axial direction of the balloon. In addition, the balloon structure 5 can be fully or partially contracted within the distal end of the main tube 3. The radial dimension of the balloon structure 5 in the uninflated state is smaller than the radial dimension of the main tube 3, which improves the permeability of the microcatheter. The drug release structure 6 is a micro-drug release orifice, which can be a cross-shaped elastic slit. The cross-shaped elastic slit is formed by two intersecting slits. When the single-layer balloon 5-1 is not inflated or the pressure inside the balloon cavity is lower than the preset drug release pressure, the balloon membranes on both sides of the slit adhere to each other under their own elasticity, so that the drug release structure 6 remains basically closed. The inflation pressure of the balloon structure is 0.5 atm–1.5 atm, the release pressure of the drug release structure is 1.5 atm–3 atm, the release pressure must be greater than the inflation pressure, and the burst pressure of the balloon structure is not less than 4 atm. When the pressure inside the balloon reaches the preset drug release pressure, the slit edge flips outward or separates, forming a drug release opening for the chemotherapy drug 13 to pass through. By selecting the balloon membrane material, balloon membrane thickness, slit length, and slit intersection angle, the opening pressure of the drug release structure 6 can be adjusted. Thus, the single-layer balloon 5-1 can be fully inflated and adhered to the wall before the drug release structure 6 opens, thereby achieving the action sequence of first blocking and then releasing the drug. After stopping the injection and reducing the pressure inside the balloon cavity, the elastic slits close again under the elastic action of the balloon membrane, which can deal with situations where it is necessary to pause and then continue perfusion, and reduce the amount of drug leakage during the low-pressure filling phase. The equivalent pore size after the drug release structure 6 is opened is preferably 50μm to 200μm. The pore size and number of pores should be matched with the injection flow rate, drug viscosity and balloon elasticity so that the balloon expansion rate in the initial injection stage is greater than the leakage rate through the drug release structure 6, thereby causing the single-layer balloon 5-1 to expand first.

[0022] During operation, the distal end of the microcatheter 1 is inserted into the tumor feeding artery 11. The balloon structure 5 is located at the target perfusion position by the imaging ring 4. Chemotherapy drug 13 is injected into the main lumen 14 through the catheter seat 2. In the initial stage, the balloon structure 5 expands first and fits against the inner wall of the tumor supply artery 11, so that the occlusion area 15 blocks the backflow gap around the outer wall of the main tube 3. During the higher-pressure phase, chemotherapy drug 13 is released from the distal drug release area 16 and flows toward the tumor 10, interacting with... Figure 12 Compared to the conventional microcatheter 9 shown, as Figure 11 As shown, the present invention restricts the backflow of chemotherapy drug 13 towards the proximal and branch arteries 12 through the balloon structure 5, such as Figure 12 As shown, some existing methods cannot limit the reflux of chemotherapy drug 13, so that chemotherapy drug 13 can cause damage to other parts of the body. After perfusion is completed, stop the injection and release the pressure in the main lumen 14 and the balloon cavity. After the balloon structure 5 retracts, withdraw the microcatheter 1. In actual use, the injection pressure, injection flow rate, and perfusion time can be set according to the target vessel diameter, balloon specifications, drug properties, and clinical treatment plan, which will not be elaborated in this embodiment; Example 2 This embodiment proposes an anti-reflux microcatheter for perfusion chemotherapy based on Embodiment 1, such as... Figure 5 As shown, in the uninflated state, the balloon structure 5 of this embodiment is squeezed into a multi-lobed folded structure. This embodiment takes a four-lobed folded structure as an example. The four-lobed folded structure here means that the balloon structure 5 forms four internally connected folded lobes along the circumference. It does not mean that the interior of the balloon structure 5 is divided into four independent chambers. The four folded lobes extend along the axial direction of the main tube 3 and are distributed at intervals around the axis of the main tube 3. When chemotherapy drug 13 enters the balloon cavity, the four folds unfold sequentially under the action of internal pressure. The balloon structure 5 changes from a squeezed state to a round, elliptical or inflated shape that matches the cross-section of the blood vessel. After perfusion is completed, pressure is released, and negative pressure is applied, the balloon membrane folds under the action of material elasticity and negative pressure, reducing the outer diameter when withdrawn. In some other embodiments, the micro-drug release orifice is located at the junction of the folded flap and the main body of the balloon structure 5. In the uninflated state, i.e. the folded state, the micro-drug release orifice is squeezed between the two. When the inflated state is completed or nearly inflated, the micro-drug release orifice can be exposed, thereby preventing drug release before the occlusion is completed. Example 3 like Figure 6 , Figure 9 and Figure 10 As shown, the difference between this embodiment and Embodiment 1 is that the balloon structure in this embodiment is a double-layer balloon 5-2, which includes an outer balloon 7 and an inner balloon 8 disposed inside the outer balloon 7. The inner balloon 8 is directly connected to the main lumen 14 of the main tube 3, and the outer balloon 7 forms a drug release chamber surrounding the inner balloon 8, and a drug release structure 6 is set in the distal region. The inner balloon 8 is provided with a predetermined rupture section 17. The predetermined rupture section 17 can be formed by a locally thinned area (i.e., the thickness of the predetermined rupture section is less than the thickness of the rest of the inner balloon), or a weak line can be pre-fabricated. After the inner balloon 8 reaches the preset rupture pressure, the predetermined rupture section 17 ruptures in a controlled manner, and the ruptured balloon membrane remains connected to the rest of the inner balloon 8 to reduce the possibility of free fragments. After rupture, the chemotherapy drug 13 enters the outer balloon 7 and is released through the drug release structure 6. Specifically, in the initial stage of injection, the chemotherapy drug 13 enters the inner balloon 8 and inflates the inner balloon 8. The inner balloon 8 pushes the outer balloon 7 outward, so that the outer balloon 7 adheres to the inner wall of the blood vessel to form a mechanical blockage. After continued pressure is applied, the predetermined rupture part 17 of the inner balloon 8 ruptures, and the main lumen 14 is connected to the drug release chamber of the outer balloon 7 through the predetermined rupture part 17. The chemotherapy drug 13 enters the drug release chamber and is released distally by the drug release structure 6.

[0023] In this embodiment, the predetermined rupture pressure of the predetermined rupture section 17 is 1.5 atm to 3 atm, the burst pressure of the outer balloon 7 is not less than 4 atm, the outer balloon 7 remains inflated during drug release, and the continuous flow provided by the injection pump is used to compensate for the leakage flow of the drug release structure 6, thereby maintaining the wall-attached pressure of the outer balloon 7. In some other embodiments, the inner balloon 8 is not an independent balloon, but a diaphragm located inside the outer balloon 7. The diaphragm divides the outer balloon 7 into a proximal cavity and a distal cavity. The proximal cavity is directly connected to the main lumen 14. After the outer balloon (i.e., the proximal cavity portion) is injected with drugs through the main lumen 14, it expands to fit the inner wall of the blood vessel. The predetermined rupture portion 17 on the diaphragm ruptures after reaching the predetermined rupture pressure, so that the distal cavity is connected to the main lumen. The chemotherapy drug solution 13 is released through the drug release structure.

[0024] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit and essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0025] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An anti-reflux microcatheter for perfusion chemotherapy, comprising a main tube, a catheter seat, a contrast ring, and a balloon structure disposed at the distal end of the main tube, wherein the main tube has a main lumen extending axially therethrough, characterized in that, The balloon structure has a balloon cavity communicating with the main lumen. The balloon structure includes a blocking area and a drug release area. The drug release area is provided with a drug release structure. After the drug is injected through the main lumen, the blocking area expands to fit the inner wall of the blood vessel and blocks the reflux gap between the microcatheter and the inner wall of the blood vessel. After the injection pressure continues to increase, the drug is released to the distal end of the balloon structure through the drug release structure.

2. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 1, characterized in that, The balloon structure can be fully or partially contracted within the distal end of the main tube, and the radial dimension of the balloon structure in the uninflated state is smaller than the radial dimension of the main tube.

3. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 1, characterized in that, The balloon structure is a single-layer balloon, with multiple drug-release structures located at the distal end of the balloon structure and distributed at intervals along the circumference or axial direction of the balloon structure.

4. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 3, characterized in that, The inflation pressure of the balloon structure is 0.5 atm–1.5 atm, the release pressure of the drug release structure is 1.5 atm–3 atm, and the burst pressure of the balloon structure is not less than 4 atm.

5. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 3, characterized in that, The drug release structure is an elastic slit. The elastic slit remains closed when the pressure is below the preset drug release pressure, and opens to release the drug when the preset drug release pressure is reached.

6. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 3, characterized in that, When the balloon structure is not inflated, it folds circumferentially to form multiple folds, which extend along the axis of the main tube and are distributed around the main tube. During inflation, the multiple folds unfold outward.

7. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 1, characterized in that, The balloon structure includes an outer balloon and a closed inner balloon disposed within the outer balloon. The inner balloon has a predetermined rupture section, the thickness of which is less than the thickness of the rest of the inner balloon.

8. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 7, characterized in that, The inner balloon is connected to the main lumen, and the outer balloon has a drug release structure. After the drug is injected into the main lumen, the inner balloon expands and causes the outer balloon to adhere to the inner wall of the blood vessel. The predetermined rupture part ruptures after the injection pressure reaches the preset rupture pressure, so that the main lumen and the outer balloon are connected, and the drug release structure completes the drug release.

9. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 1, characterized in that, The inner balloon is a diaphragm located inside the outer balloon. The diaphragm divides the outer balloon into a proximal cavity and a distal cavity. The proximal cavity is directly connected to the main lumen. After the outer balloon is injected with drugs through the main lumen, it expands to fit the inner wall of the blood vessel. The predetermined rupture section on the diaphragm ruptures after reaching the predetermined rupture pressure, so that the distal cavity is connected to the main lumen. Drug release is completed through the drug release structure.

10. The anti-reflux microcatheter for perfusion chemotherapy as described in claim 7, characterized in that, The predetermined rupture pressure of the predetermined rupture section is 1.5 atm to 3 atm, and the burst pressure of the outer balloon is not less than 4 atm.

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