A non-penetrating microcatheter for local administration and a medical device comprising the same

Abstract

The application provides a micro catheter for local administration, which comprises a delivery section, a fixed section, a perforated section and a terminal section from proximal end to distal end, the delivery section, the fixed section and the perforated section have a communicating inner cavity, the outer diameter is 1.5F to 5F, and the inner diameter is 0.40mm to 1.5mm; the length of the terminal section is 1 to 40mm, and a guide wire through hole is arranged; the fixed section has a preformed arc-shaped outer shape; the end of the perforated section is blocked, a first side perforation is arranged on the perforated section, and a second side perforation is arranged on the top outside of the arc-shaped outer shape of the fixed section. The micro catheter is not prone to thrombosis for long-term placement in an artery, is suitable for being placed in the body for local arterial or venous administration of patients with coronary artery, head, liver, kidney, lung, peripheral vascular diseases and the like, and can reduce the administration amount to less than 20% of the conventional administration amount.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and in particular to a non-penetrating microcatheter for local drug delivery and a medical device comprising the same. Background Technology

[0002] Treatment of areas such as the coronary arteries, head, liver, and cancer patients often involves prolonged administration of medication via local arteries. To achieve the required drug concentration in the treatment area, higher doses are typically required, leading to drug side effects and organ damage. Local administration effectively addresses the drug-related damage associated with conventional methods, particularly for cancer patients, significantly reducing the adverse effects of overdose. Furthermore, cardiovascular disease patients often require anticoagulants. Patients taking anticoagulants who also have other conditions requiring surgery face significant risks. For example, surgery for gastrointestinal bleeding necessitates discontinuing anticoagulants, greatly increasing the risk of myocardial infarction. Similarly, lung cancer patients with concurrent heart disease often require stent implantation before surgery, as they may not tolerate anesthesia or the procedure itself. Once a stent is implanted, continuous oral antiplatelet therapy for up to a year is routinely necessary, increasing the risk of postoperative hemorrhage – a seemingly insurmountable problem. Local anticoagulant administration effectively mitigates these risks, thus necessitating a simple and effective method for local drug delivery. Summary of the Invention

[0003] This invention provides a microcatheter for local drug delivery, comprising the following embodiments:

[0004] Implementation Method 1: A microcatheter for local drug delivery, comprising, from proximal to distal: a delivery segment, a fixation segment, an opening segment, and a distal segment; the delivery segment, fixation segment, and opening segment have communicating lumens, with an outer diameter of 1.5F to 5F and an inner diameter of 0.40mm to 1.5mm; the distal segment has a length of 1 to 40mm and is provided with a guidewire through-hole; the fixation segment has a pre-formed arc shape for fixing the position of the microcatheter relative to the blood vessel by its shape after the microcatheter is installed; the end of the opening segment is sealed, thereby preventing communication between the opening segment and the distal segment; the opening segment is provided with a first side opening; a marker is provided near the opening segment, for example, at the connection between the opening segment and the fixation segment, to help external devices detect its position in the patient's body; a second side opening is provided on the outer side of the top of the arc shape of the fixation segment; the outer surface of the microcatheter is provided with an anticoagulant coating.

[0005] Embodiment 2: A microcatheter for local drug delivery according to Embodiment 1, wherein the length of the distal segment is 6 mm to 20 mm.

[0006] Embodiment 3: The microcatheter for local drug delivery according to Embodiment 1, wherein the outer diameter of the delivery section, the fixing section and the opening section is 1.7F to 4F, preferably 1.7 to 2.6F, and the inner diameter is 0.45mm to 1.2mm.

[0007] Implementation Method 4: The microcatheter for local drug delivery according to Implementation Method 1, wherein the anticoagulant coating is a heparin coating, a phosphocholine coating, or a heparin-like coating, etc., and the inner and outer surfaces of the microcatheter are provided with an anticoagulant coating.

[0008] Embodiment 5: A microcatheter for local drug delivery according to Embodiment 1, wherein both the inner and outer surfaces of the microcatheter are provided with an anticoagulant coating.

[0009] Embodiment 6: A microcatheter for local drug delivery according to Embodiment 1, wherein the length of the delivery segment is 0.4 to 1.5 m, 0.7 to 1.3 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

[0010] Embodiment 7: A microcatheter for local drug delivery according to Embodiment 1, wherein a first side opening on the opening segment is provided at the proximal end of the opening segment, and 2 to 20 openings are provided along the circumferential direction of the catheter.

[0011] Implementation Method 8: A microcatheter for local drug delivery according to Implementation Method 1, wherein the arc-shaped profile has a height of 2 mm to 40 mm and a span of 2 mm to 60 mm.

[0012] Implementation 9: The microcatheter for local drug delivery according to Implementation 1, wherein the number of second side openings disposed on the outer side of the top of the arc-shaped shape is 1 to 4.

[0013] Implementation 10: The microcatheter for local drug delivery according to Implementation 1, wherein the total area of ​​the second side opening disposed on the outer side of the top of the arc-shaped profile of the fixed section does not exceed one-fifth of the total area of ​​the first side opening disposed on the opening section.

[0014] Embodiment 11: A microcatheter for local drug delivery according to Embodiment 1, wherein the microcatheter further includes a proximal infusion pump connector segment, the outer diameter of which is less than or equal to 6F.

[0015] Embodiment 12: A microcatheter for local drug delivery according to Embodiment 11, wherein the delivery section, fixation section and opening section comprise a PTEF inner layer, a metal braided middle layer and a nylon outer layer.

[0016] Embodiment 13: A microcatheter for local drug delivery, comprising, from proximal to distal: a delivery segment, an opening segment, a fixation segment, and a distal segment; the delivery segment, the opening segment, and at least a portion of the fixation segment have communicating lumens, with an outer diameter of 1.5F to 5F and an inner diameter of 0.40mm to 1.5mm; the distal segment is substantially straight and has a length of 1 to 40mm; the fixation segment has a pre-formed arcuate shape for fixing the position of the microcatheter relative to a blood vessel by its shape after the microcatheter is placed, while the straight distal segment is free in the blood vessel; a first lateral opening is provided on the opening segment, and a [missing information - likely a device or structure] is disposed near the opening segment. Markers are provided, for example, at the connection between the opening section and the fixing section and / or at the connection between the opening section and the delivery section, to help external devices detect their position in the patient's body; a second side opening is provided on the outer side of the top of the arc-shaped shape of the fixing section; the fixing section or the end section is blocked, so that the fixing section and the end section are not connected; the blocking point is located downstream of the second side opening provided on the outer side of the top of the arc-shaped shape, so that the second side opening provided on the outer side of the top of the arc-shaped shape is connected to the inner cavity; the end section and optionally the fixing section are provided with guide wire through holes, and the guide wire through holes are located downstream of the blocking point;

[0017] The outer surface of the microcatheter is coated with an anticoagulant coating.

[0018] Embodiment 14: A microcatheter for local drug delivery according to Embodiment 13, wherein the length of the distal segment is 6 mm to 20 mm.

[0019] Embodiment 15: A microcatheter for local drug delivery according to Embodiment 13, wherein the outer diameter of the delivery section and the opening section is 1.7F to 4F, preferably 1.7 to 2.6F, and the inner diameter is 0.45mm to 1.2mm.

[0020] Embodiment 16: A microcatheter for local drug delivery according to Embodiment 13, wherein the anticoagulant coating is a heparin coating, a phosphocholine coating, or a heparin-like coating.

[0021] Embodiment 17: A microcatheter for local drug delivery according to Embodiment 13, wherein both the inner and outer surfaces of the microcatheter are provided with an anticoagulant coating.

[0022] Embodiment 18: A microcatheter for local drug delivery according to Embodiment 13, wherein the length of the delivery segment is 0.4 to 1.5 m, 0.7 to 1.3 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

[0023] Embodiment 19: A microcatheter for local drug delivery according to Embodiment 13, wherein a first side opening is provided at the proximal end of the opening segment, and 2 to 20 openings are provided along the circumferential direction of the catheter.

[0024] Embodiment 20: A microcatheter for local drug delivery according to Embodiment 13, wherein the arcuate shape has a height of 2 mm to 40 mm and a span of 2 mm to 60 mm.

[0025] Implementation 21: The microcatheter for local drug delivery according to Implementation 13, wherein the number of second side openings disposed on the outer side of the top of the arcuate shape is 1 to 4.

[0026] Embodiment 22, the microcatheter for local drug delivery according to claim 13, wherein the total area of ​​the second side opening disposed on the outer side of the top of the arcuate shape of the fixed section does not exceed one-fifth of the total area of ​​the first side opening disposed on the opening section.

[0027] Embodiment 23: A microcatheter for local drug delivery according to Embodiment 13, wherein the microcatheter further includes a proximal infusion pump connector section, the outer diameter of which is less than or equal to 6F.

[0028] Embodiment 24: A microcatheter for local drug delivery according to Embodiment 23, wherein the delivery section and the opening section comprise a PTEF inner layer, a metal braided middle layer, and a nylon outer layer.

[0029] Embodiment 25: A medical device for local drug delivery, comprising a guide tube, a guidewire, an auxiliary tube, a detachable Luer connector, and a microcatheter as described in any one of Embodiments 1-24, wherein the inner diameter of the auxiliary tube is smaller than the outer diameter of the proximal end of the microcatheter, the outer diameter of the guidewire is smaller than the inner diameter of the guidewire through-hole, the outer diameter of the auxiliary tube is larger than the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube is larger than the outer diameter of the microcatheter, thereby allowing the guide tube to be withdrawn with the assistance of the auxiliary tube after it has been used to assist in setting the guidewire and microcatheter, leaving the microcatheter in the human body.

[0030] Embodiment 26: A medical device for local drug delivery according to Embodiment 25, wherein the outer diameter of the auxiliary tube is smaller than the inner diameter of the guide tube.

[0031] Embodiment 27. A medical device for local drug delivery, comprising a guide tube, a guide wire, an auxiliary wire, a detachable Luer connector, and a microcatheter as described in any one of Embodiments 1-24, wherein the outer diameter of the guide wire is smaller than the inner diameter of the guide wire through-hole, the outer diameter of the auxiliary wire is larger than the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube is larger than the outer diameter of the microcatheter, thereby allowing the guide tube to be withdrawn with the assistance of the auxiliary wire after it has been used to assist in setting the guide wire and the microcatheter, leaving the microcatheter in the human body.

[0032] Embodiment 28: A medical device for local drug delivery according to Embodiment 27, wherein the outer diameter of the auxiliary wire is smaller than the inner diameter of the guide tube.

[0033] Embodiment 29. A medical device for local drug delivery according to Embodiment 27, wherein the distal end of the auxiliary wire has an extended connecting segment, the outer diameter of which is smaller than the inner diameter of the proximal end of the microcatheter, so that the extended connecting segment can be inserted into the proximal end of the microcatheter.

[0034] The size and shape characteristics of the microcatheter described in this application enable highly selective intra-arterial drug delivery over a longer period, reducing the dosage to less than 20% of the conventional dosage and avoiding the impact on other organs caused by over-drug administration. The microcatheter described in this application is relatively fixed to the blood vessel for extended periods with minimal displacement. The micropore at the delivery end continuously drains fluid, reducing contact with the target vascular endothelium. The slender extension floats within the blood vessel, minimizing damage to the vascular endothelium. This application specifies that the fixed section has a second side opening on the outer side of its arc-shaped top, allowing anticoagulant drugs to flow out through this opening, preventing thrombosis at this site. This further optimizes the anticoagulant performance of the microcatheter, preventing thrombosis even after prolonged placement in arteries / venous veins. It is suitable for selective local drug delivery to the coronary arteries, head, and liver, and for local chemotherapy administration in cancer patients, reducing damage to other parts of the body and organs caused by chemotherapy drugs. It is also suitable for local antibiotic administration, local anticoagulant / procoagulant administration, etc. For example, the microcatheter of this application is particularly suitable for interventional treatment of patients with acute coronary syndrome complicated by gastrointestinal bleeding. This involves performing stent placement without anticoagulants during gastrointestinal bleeding, followed by local anticoagulation administration via the microcatheter, while simultaneously treating the gastrointestinal bleeding surgically or with medication. After complete hemostasis, oral antiplatelet medication is administered, and the microcatheter is removed. As another example, the microcatheter of this application is particularly suitable for patients with severe coronary artery disease who cannot undergo lung cancer resection under anesthesia. Coronary intervention can be performed without systemic anticoagulation, and the microcatheter can be retained for anticoagulation before lung cancer resection. After complete hemostasis following lung cancer surgery, oral antiplatelet medication is administered, and the microcatheter is removed. It is also suitable for local medication administration in other situations. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0036] Figure 1 This is a schematic diagram of the microcatheter used for local drug delivery in Example 1;

[0037] Figure 2 This is a partial schematic diagram of the microcatheter used for local drug delivery in Example 1;

[0038] Figure 3 This is a schematic diagram of the microcatheter used for local coronary artery drug delivery in Example 2;

[0039] Figure 4 This is a partial schematic diagram of the microcatheter used for local coronary artery drug delivery in Example 2;

[0040] Figures 5 to 12 This is a schematic diagram of a locally administered medical device placed in the body in Example 2;

[0041] Figure 13 This is a schematic diagram of the microcatheter used for local drug delivery in cerebral blood vessels in Example 3.

[0042] Figure descriptions: 10-Microcatheter, 100-Delivery section, 110-Inner lumen, 200-Fixed section, 210-Second side opening (fixed section), 300-Opening section, 310-First side opening (opening section), 320-Marker, 400-End section, 500-Injection pump connector section, 600-Guidewire, 610-Guidewire through-hole, 700-Guide tube, 800-Auxiliary wire, 810-Extended connecting section, 900-Luer connector, 910-Female connector, 911-Extension, 920-Male connector, 921-Fixed section. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0044] This invention provides a microcatheter for local drug delivery, comprising, from proximal to distal: a delivery segment, a fixation segment, an opening segment, and a distal segment. The delivery segment, fixation segment, and opening segment have communicating lumens, with an outer diameter of 1.5F to 5F and an inner diameter of 0.40mm to 1.5mm. The distal segment has a length of 1 to 40mm (e.g., 2mm to 35mm, 4mm to 30mm, 6mm to 25mm) and is provided with a guidewire through-hole. The fixation segment has a pre-formed arcuate shape for positioning the microcatheter. The microcatheter is then positioned relative to the blood vessel by its shape. The end of the opening segment is sealed, thus preventing communication between the opening segment and the terminal segment. A second side opening is provided on the opening segment, and markers are placed near the opening segment, such as at the connection between the opening segment and the fixed segment, to help external devices detect its position in the patient's body. A first side opening is provided on the outer side of the top of the arc-shaped fixed segment. An anticoagulant coating is provided on the outer surface of the microcatheter. In this application, the division between each segment of the microcatheter is not completely fixed because the functions of these segments overlap. For example, among segments with connected lumens, although the fixed segment has the function of fixing the microcatheter to the blood vessel, it still has the function of the delivery segment. For example, the boundary between the opening segment and the fixed segment may not be particularly clear. However, generally speaking, the starting point of the opening segment can be the opening, and the ending point of the opening segment can be the sealing point. The starting point of the fixed segment can be the starting point of the arc-shaped segment, and the ending point can be the ending point of the arc-shaped segment. The division of the starting and ending points of the fixed segment can be appropriately adjusted according to the division of the two segments connected to it, without any particularly clear restrictions, as long as the desired purpose or effect can be achieved functionally. Similarly, the division of other segments can also be made according to the actual situation and the functions to be achieved. In addition, those skilled in the art should understand that the microcatheter described in this application is flexible, and the shape described in this application is a similar shape exhibited by the microcatheter in its natural state, as well as a shape that can be achieved according to the understanding of those skilled in the art. The overall shape of the microcatheter is adapted to the vascular path in the implanted body, which can more conveniently implant the microcatheter into the target area and adapt to long-term placement in blood vessels. For example, for microcatheters used for local drug delivery in the coronary arteries, the delivery segment and the terminal segment and / or the opening segment form an angle of about 70-120 degrees (e.g., about 90 degrees) to more smoothly deliver and place in the coronary artery. For another example, for microcatheters used for local drug delivery in the liver or head blood vessels, the delivery segment, the opening segment, and the terminal segment are basically straight in the axial direction of the microcatheter. Those skilled in the art can reasonably set the overall shape of the microcatheter according to the implantation area.That is, the connection line between the beginning and end of the arc of the fixed segment and the transition between the front and rear segments can form a certain angle, such as 70-160°, 80-150°, 90° to 120°, or straight (i.e. 180°). Those skilled in the art can set it according to actual needs without any particular restrictions.

[0045] In this application, the unit F has the meaning commonly understood by those skilled in the art: 1F refers to a microcatheter with a circumference of 1 mm, 1.5F refers to a microcatheter with a circumference of 1.5 mm, and 4F refers to a microcatheter with a circumference of 4.0 mm. In this application, "outer diameter of 1.5F to 5F" refers to the outer diameter when the circumference is between 1.5F and 5F. The shape of the microcatheter described in this application allows for prolonged placement in the body for local drug delivery via blood vessels, making it suitable for applications such as the head, liver, and coronary artery regions of the heart, and for long-term retention in the patient's body during surgery. The outer diameter of the microcatheter described in this application is 1.5F to 5F, a size that allows the microcatheter to be placed in the body for extended periods without causing hemolysis or other adverse reactions. The delivery section, fixation section, and opening section of the microcatheter described in this application have a through-lumen with an inner diameter of 0.40 mm to 1.5 mm, a size that allows drug delivery via a high-pressure injection pump. The distal section has a guidewire orifice to accommodate a guidewire for microcatheter placement and allows it to move freely within the blood vessel. The pre-formed arc shape has a height of 2mm to 40mm and a span of 2mm to 60mm, which can be selected according to the blood vessel to be installed. For example, the height of the pre-formed arc shape is 2mm to 35mm, or 4mm to 30mm, or 8mm to 25mm, or 2mm to 12mm. The span of the pre-formed arc shape is 2mm to 50mm, or 4mm to 50mm, or 8mm to 45mm, or 12mm to 40mm, or 20mm to 35mm, or 2mm to 12mm. The arc shape fixes the microcatheter relatively in the blood vessel, so that the microcatheter does not shift. When placed in the body for a long time, it does not cause much damage to the vascular intima, nor does it affect blood flow, which is convenient for local drug delivery.

[0046] In this application, when the arc-shaped microcatheter is relatively fixed within a blood vessel, the top of the arc-shaped shape usually rests against the vessel wall, making it prone to thrombus formation. This application specifies that "a second side opening is provided on the outer side of the top of the arc-shaped shape of the fixed section," thereby allowing anticoagulant drugs to flow out through the second side opening located on the outer side of the top of the arc-shaped shape, preventing thrombus formation at this location, further optimizing the anticoagulant performance of the microcatheter, and making it less likely for thrombus to form when the microcatheter is placed in the artery for a long period of time. In this application, the top of the arc-shaped shape refers to the middle section of the arc-shaped shape, that is, the area occupying 1 / 3 of the middle length of the arc-shaped shape. The outer side of the arc-shaped shape refers to the side of the arc-shaped shape that rests against the vessel wall. Placing the second side opening on the outer side of the top of the arc-shaped shape is more conducive to preventing thrombus formation at this location. In some preferred embodiments, the second side opening is located on the outer side within a range of 0.5mm to 10mm from the apex of the arc-shaped shape.

[0047] The first side opening on the perforated section communicates with the inner lumen, while the perforated section and the end section are not connected. This allows the drug in the inner lumen to flow out through the first side opening on the perforated section and the second side opening located on the outer side of the top of the arc-shaped top of the fixed section, delivering it to the target area. Those skilled in the art can rationally set the number of first side openings based on the range of the target drug delivery area. For example, 2 to 20, or 2 to 4, can be set along the circumference of the catheter on the outer periphery of the perforated section, or one opening every 30-120° along the circumference of the catheter on the outer periphery of the perforated section. For accurate positioning, a marker (marker material) is provided between the fixed section and the perforated section. This marker helps external devices detect its position within the patient's body. The applicant of this application unexpectedly discovered that the size setting of the microcatheter can reduce the drug dosage to less than 20% of the conventional dosage, avoiding the effects of over-drug administration on other organs. The microcatheter, when placed in a vein, does not form thrombi within 24 hours and when placed in an artery, it is unlikely to form thrombi even with prolonged placement. It is suitable for local drug administration to patients with coronary artery, head, liver, and other diseases via blood vessels. It is also suitable for local chemotherapy administration to cancer patients, reducing damage to other parts of the body and organs caused by chemotherapy drugs. It is particularly suitable for patients with coronary artery disease who have bleeding or contraindications to surgery but urgently need surgical treatment, i.e., patients who are not suitable for taking anticoagulants or antiplatelet drugs in the short term. It allows for a transition period created by local anticoagulation during interventional therapy using the microcatheter described in this application, enabling surgery or hemostasis. It is particularly suitable for patients with malignant tumors and coronary heart disease, allowing for safe simultaneous tumor resection surgery under local coronary anticoagulation administration after coronary intervention. It is also suitable for local drug administration in other situations.

[0048] In some embodiments, the length of the distal segment is 6 mm to 20 mm. A suitable distal segment length facilitates guiding the catheter through the guidewire to the target area. There are no restrictions on the specific shape of the distal segment.

[0049] In some implementations, the distal end is straight and floats freely within the blood vessel in its use state. Typically, for accurate positioning, a marker (marker material) is placed near the opening segment to assist external devices in detecting its location within the patient. The microcatheter is shaped to allow for localized drug delivery via blood vessels, such as to the head, liver, or coronary arteries, and remains in the patient's body for extended periods during surgery (e.g., more than 24 hours, or even 3-12 days).

[0050] In some embodiments, the outer diameter of the delivery section, fixing section and opening section is 1.7F to 4F, preferably 1.7 to 2.6F, and the inner diameter is 0.45mm to 1.2mm. This size design does not affect blood circulation in the body and is not prone to thrombosis, thus achieving better local drug delivery effect.

[0051] In some embodiments, the anticoagulant coating is a heparin coating, a phosphocholine coating, or a heparin-like coating. By coating the outer surface of the microcatheter with a heparin coating, a phosphocholine coating, or a heparin-like anticoagulant coating, thrombus formation can be effectively prevented, achieving a local anticoagulant effect.

[0052] In some embodiments, an anticoagulant coating is provided on both the inner and outer surfaces of the microcatheter. By coating the inner and outer surfaces of the microcatheter with an anticoagulant coating, clotting can be minimized.

[0053] In some embodiments, the delivery section is 0.4 to 1.5 m long. This length setting makes the microcatheter widely applicable for local coronary artery drug delivery, local chemotherapy for liver cancer, and local intravenous drug delivery.

[0054] In some embodiments, the delivery section has a length of 0.7 to 1.3 m or 0.8 to 1.3 m. This length setting makes the microcatheter particularly suitable for local coronary artery drug delivery.

[0055] In some embodiments, the delivery section is 1.1 to 1.3 m long. This length makes the microcatheter particularly suitable for local coronary artery drug delivery.

[0056] In some embodiments, the first side opening on the opening segment is located at the proximal end of the opening segment, and 2 to 20 openings are arranged circumferentially along the catheter. The proximal end of the opening segment is the starting point of the opening segment, and the distance between the first side opening and the end of the microcatheter (i.e., the farthest end of the microcatheter) is less than 40 mm, for example, less than 20 mm.

[0057] In some embodiments, the arc height of the arc shape is 2mm to 40mm, and the span of the arc shape is 2mm to 60mm.

[0058] In some embodiments, the number of second side openings provided on the outer side of the top of the arcuate shape is 1 to 4.

[0059] In some embodiments, the total area of ​​the second side opening located on the outer side of the top of the arc-shaped top of the fixed section does not exceed one-fifth of the total area of ​​the first side opening located on the opening section. There is no particular limitation on the area of ​​a single side opening, and those skilled in the art can set it as needed. The main function of the second side opening located on the outer side of the top of the arc-shaped top of the fixed section is to prevent thrombosis at this location. It only needs to meet the drug outflow requirements to prevent thrombosis, and its total area is less than one-fifth of the total area of ​​the first side opening located on the opening section. This allows for maintaining good anticoagulant properties while minimizing the dosage.

[0060] In some embodiments, the microcatheter further includes a proximal infusion pump connector section with an outer diameter of 6F or less, for example, 1.5F to 5F, for example, 5.5F or less. The infusion pump connector section can connect to a high-pressure infusion pump tubing, allowing medication to be delivered to the local drug delivery area through the lumen of the microcatheter. In some preferred embodiments, the infusion pump connector section is provided with a detachable or micro-Luer taper for connection to the infusion pump.

[0061] In some embodiments, the conveying section, fixing section, and perforated section comprise a PTEF inner layer, a metal braided middle layer, and a nylon outer layer. In some embodiments, the conveying section, fixing section, and perforated section comprise a metal wire inner layer and a polycarbonate skin.

[0062] In some embodiments, the delivery section, fixing section, opening section, and end section each independently adopt a three-layer structure, wherein the inner layer is made of polytetrafluoroethylene material (i.e., PTEF inner layer), the middle layer is a 304 stainless steel wire mesh layer as support (i.e., metal braided middle layer), and the outer layer is wrapped with nylon 12 (i.e., nylon outer layer). There are no limitations on the preparation method of the microcatheter or medical device described in this application; those skilled in the art can select appropriate methods, manufacturing equipment, and materials according to actual needs.

[0063] The present invention also provides a microcatheter for local drug delivery, comprising, from proximal to distal: a delivery segment, an opening segment, a fixation segment, and a distal segment. The delivery segment, the opening segment, and at least a portion of the fixation segment have communicating lumens with an outer diameter of 1.5F to 5F and an inner diameter of 0.40mm to 1.5mm. The distal segment is substantially straight and has a length of 1 to 40mm (e.g., 2mm to 35mm, 4mm to 30mm, 6mm to 25mm). The fixation segment has a pre-formed arcuate shape (the arcuate shape has a height of 2mm to 40mm and a span of 2mm to 60mm, selected according to the required blood vessel), used to fix the position of the microcatheter relative to the blood vessel by its shape after placement, while the straight distal segment remains free in the blood vessel. The opening segment has a first side opening (the number of first side openings should not be too large, for example, in the opening...). Two to 20 or 2 to 4 orifices are provided on the outer periphery of the catheter along the circumference of the opening segment, or one orifice is provided every 30°-120° along the circumference of the catheter on the outer periphery of the opening segment (opening at the beginning of the opening segment). Markers are provided near the opening segment, such as at the connection between the opening segment and the fixation segment and / or the connection between the opening segment and the delivery segment, to help external devices detect their position in the patient's body. A second side opening is provided on the outer side of the top of the arc-shaped shape of the fixation segment. The fixation segment or the end segment is blocked, so that the fixation segment and the end segment are not connected. The blockage is located downstream of the second side opening provided on the outer side of the top of the arc-shaped shape, so that the second side opening provided on the outer side of the top of the arc-shaped shape is connected to the lumen. The end segment and optionally the fixation segment are provided with guidewire through holes, which are located downstream of the blockage. An anticoagulant coating is provided on the outer surface of the microcatheter.

[0064] The microcatheter described in this application has a shape that allows for prolonged placement within the body to administer medication locally via blood vessels. It is suitable for areas such as the coronary arteries, head, liver, kidneys, lungs, and peripheral vascular diseases, and can be retained in the patient's body long-term during surgery. The outer diameter of the microcatheter described in this application is 1.5F to 5F, a size that allows for long-term placement without causing hemolysis or other adverse reactions. The delivery section and the opening section of the microcatheter described in this application have a through lumen with an inner diameter of 0.40mm to 1.5mm, a size that allows for medication administration via a high-pressure infusion pump. The distal section and optionally the fixing section are provided with guidewire through-holes to accommodate guidewires for catheter placement and allow the catheter to move freely within the blood vessel. The pre-formed arc-shaped shape has a height of 2mm to 40mm and a span of 2mm to 60mm, which can be selected according to the required blood vessel. For example, the arc-shaped shape has a height of 2mm to 35mm, 4mm to 30mm, 8mm to 25mm, or 2mm to 12mm, and a span of 2mm to 50mm, 4mm to 50mm, 8mm to 45mm, 12mm to 40mm, 20mm to 35mm, or 2mm to 12mm. The arc-shaped shape fixes the microcatheter relatively within the blood vessel, preventing displacement of the microcatheter and not affecting blood flow, facilitating local drug delivery. When the fixing section has a guidewire through-hole located downstream of the occlusion point, the shape of the fixing section matches the shape of the guidewire when the microcatheter enters the blood vessel along the guidewire, facilitating implantation. After the guidewire is withdrawn, the fixing section returns to its arc shape, fixing the position of the microcatheter and the blood vessel. The first side opening on the perforated section is connected to the inner cavity, so that the drug in the inner cavity can reach the target area through the first side opening. Too many first side openings can easily lead to a decrease in the strength of the microcatheter. The number of first side openings should not be too many. Those skilled in the art can reasonably set the number of first side openings according to the range of the drug delivery target area. For example, 2 to 20 openings can be set along the circumference of the catheter. For example, one opening can be set every 120° on the outer periphery of the perforated section, that is, three first side openings can be set on the outer periphery of the perforated section.

[0065] This application specifies that "a second side opening is provided on the outer side of the top of the arc-shaped fixed section, and the fixed section or the terminal section is blocked, so that the fixed section and the terminal section are not connected." The blocking point can be located on the fixed section or the terminal section. The second side opening of the fixed section communicates with the inner lumen and is located upstream of the blocking point, so that anticoagulant drugs can flow out through the second side opening on the outer side of the top of the arc-shaped fixed section, preventing thrombosis at this site, further optimizing the anticoagulant performance of the microcatheter, and making it less likely for thrombosis to form when the microcatheter is placed in the artery for a long time. In this application, upstream refers to the proximal end relative to the operator, and downstream refers to the distal end relative to the operator.

[0066] For accurate positioning, markers (marker materials) are provided between the fixed section and the open section and / or between the open section and the delivery section. These markers help external devices detect their position within the patient's body. The applicant of this application unexpectedly discovered that the size of the microcatheter can reduce the dosage to less than 20% of the conventional dosage, avoiding the impact on other organs caused by over-administration. The microcatheter does not form thrombi within 24 hours when placed in a vein, and is unlikely to form thrombi long-term when placed in an artery. It is suitable for local administration of medication to the coronary arteries, head, liver, kidneys, lungs, and peripheral vascular diseases via blood vessels. It is also suitable for local administration of chemotherapy drugs to cancer patients, reducing damage to other parts of the body and organs caused by chemotherapy drugs. It is particularly suitable for surgical treatment of gastrointestinal bleeding in patients with coronary artery disease, i.e., during gastrointestinal bleeding, anticoagulants are not taken orally, but local anticoagulant administration is performed through the microcatheter described in this application to treat the gastrointestinal bleeding. It is particularly suitable for local anticoagulant administration in cases of acute coronary syndrome requiring urgent surgery, where the microcatheter remains in the patient's body during surgery for continuous local administration, greatly reducing surgical risks. It is also applicable to local administration in other situations.

[0067] In some embodiments, the length of the distal segment is 6 mm to 20 mm. A suitable distal segment length facilitates the guidance of the catheter to the target area via a guidewire.

[0068] In some embodiments, the outer diameter of the delivery section and the opening section is 1.7F to 4F, preferably 1.7 to 2.6F, and the inner diameter is 0.45mm to 1.2mm. This size design does not affect blood circulation in the body and is not prone to thrombosis, thus achieving better local drug delivery.

[0069] In some embodiments, the anticoagulant coating is a heparin coating, phosphoric acid choline, or heparin-like coating, optionally being hydrophilic. By coating the outer surface of the microcatheter with a heparin or heparin-like anticoagulant coating, thrombus formation can be effectively prevented, achieving a local anticoagulant effect.

[0070] In some embodiments, an anticoagulant coating is provided on both the inner and outer surfaces of the microcatheter. By coating the inner and outer surfaces of the microcatheter with an anticoagulant and then immersing the microcatheter in an anticoagulant, clotting can be minimized.

[0071] In some embodiments, the delivery section is 0.4 to 1.5 m long. This length setting makes the microcatheter widely applicable for local coronary artery drug delivery, local chemotherapy for liver cancer, and local intravenous drug delivery.

[0072] In some embodiments, the delivery section has a length of 0.7 to 1.3 m or 0.8 to 1.3 m. This length setting makes the microcatheter particularly suitable for local coronary artery drug delivery.

[0073] In some embodiments, the delivery section is 1.1 to 1.3 m long. This length makes the microcatheter particularly suitable for local coronary artery drug delivery.

[0074] In some embodiments, the first side opening on the opening segment is located at the proximal end of the opening segment, and 2 to 20 openings are arranged circumferentially along the catheter. The proximal end of the opening segment is the starting point of the opening segment, and the distance between the first side opening and the end of the microcatheter (i.e., the farthest end of the microcatheter) is less than 60 mm, for example less than 40 mm, for example less than 20 mm.

[0075] In some embodiments, the arc height of the arc shape is 2mm to 40mm, and the span of the arc shape is 2mm to 60mm.

[0076] In some embodiments, the number of second side openings provided on the outer side of the top of the arcuate shape is 1 to 4.

[0077] In some embodiments, the total area of ​​the second side opening located on the outer side of the top of the arc-shaped top of the fixed section does not exceed one-third, preferably one-fifth, of the total area of ​​the first side opening located on the opening section. There is no particular limitation on the area of ​​a single side opening; those skilled in the art can set it as needed. The main function of the second side opening located on the outer side of the top of the arc-shaped top of the fixed section is to prevent thrombosis at this location. It only needs to meet the drug outflow requirements to prevent thrombosis, and its total area is less than one-third, preferably less than one-fifth, of the total area of ​​the first side opening located on the opening section. This allows for minimizing the dosage while maintaining good anticoagulant properties.

[0078] In some embodiments, the microcatheter further includes a proximal infusion pump connector section with an outer diameter of 6F or less, for example, 1.5F to 5F, or for example, 5.5F or less. The infusion pump connector section can connect to a high-pressure infusion pump tubing, allowing medication to be delivered to the local drug delivery area through the lumen of the microcatheter. In some preferred embodiments, the infusion pump connector section is provided with a Luer taper for connection to the infusion pump.

[0079] In some embodiments, the conveying section and the perforated section comprise a PTEF inner layer, a metal braided middle layer, and a nylon outer layer. In some embodiments, the conveying section and the perforated section comprise a metal wire inner layer and a polycarbonate skin.

[0080] In some embodiments, the delivery section, fixing section, opening section, and end section each independently adopt a three-layer structure, wherein the inner layer is made of polytetrafluoroethylene, the middle layer is a 304 stainless steel wire mesh layer as support, and the outer layer is wrapped with nylon 12. There are no limitations on the preparation method of the microcatheter or medical device described in this application; those skilled in the art can select appropriate methods, manufacturing equipment, and materials according to actual needs.

[0081] This application also discloses a medical device for local drug delivery, comprising a guide tube, a guidewire, an auxiliary tube, a detachable Luer connector, and the microcatheter. The inner diameter of the auxiliary tube is smaller than the outer diameter of the proximal end of the microcatheter, the outer diameter of the guidewire is smaller than the inner diameter of the guidewire's through-hole, the outer diameter of the auxiliary tube is greater than or equal to the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube (also known as a guiding catheter) is greater than the outer diameter of the microcatheter. This allows the guide tube to be withdrawn with the assistance of the auxiliary tube after it has been used to assist in setting the guidewire and microcatheter, leaving the microcatheter in the body. When withdrawing the guide tube, the auxiliary tube is used externally to hold the proximal end of the microcatheter against the guide tube, allowing the guide tube to be withdrawn without affecting the microcatheter's position in the body. After withdrawal, the microcatheter is connected to an infusion pump via the Luer connector for local drug delivery. Furthermore, after the auxiliary tube is used externally to hold the proximal end of the microcatheter against the guide tube, the guidewire can also be withdrawn with the assistance of the auxiliary tube without affecting the microcatheter's position in the body.

[0082] In some embodiments, the outer diameter of the auxiliary tube is smaller than the inner diameter of the guide tube. In this case, the auxiliary tube can be inserted into the guide tube, and the guide tube can be withdrawn along the auxiliary tube.

[0083] This application also discloses a medical device for local drug delivery, comprising a guide tube, a guidewire, an auxiliary wire, a detachable Luer connector, and the aforementioned microcatheter. The outer diameter of the guidewire is smaller than the inner diameter of the guidewire orifice, the outer diameter of the auxiliary wire is larger than the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube is larger than the outer diameter of the microcatheter. This allows the guide tube, after assisting in the placement of the guidewire and microcatheter, to be withdrawn with the assistance of the auxiliary wire, leaving the microcatheter in the body. When withdrawing the guide tube, the proximal end of the microcatheter is held in place externally by the auxiliary wire, allowing the guide tube to be withdrawn without affecting the microcatheter's position within the body. After withdrawal, the microcatheter is connected to an infusion pump via the Luer connector for local drug delivery. Furthermore, after holding the proximal end of the microcatheter in place externally by the auxiliary wire, the guidewire can also be withdrawn with the assistance of the auxiliary wire without affecting the microcatheter's position within the body.

[0084] In some embodiments, the outer diameter of the auxiliary wire is smaller than the inner diameter of the guide tube. In this case, the auxiliary wire can be inserted into the guide tube, and the guide tube can be withdrawn along the auxiliary wire.

[0085] In some embodiments, the distal end of the auxiliary wire has an extended connecting segment whose outer diameter is smaller than the inner diameter of the proximal end of the microcatheter, so that the extended connecting segment can be inserted into the proximal end of the microcatheter.

[0086] The preparation method of the microcatheter described in this application is not particularly required and can be prepared by methods known to those skilled in the art. The strength of the microcatheter is not particularly required and can be the strength of microcatheters commonly used in the art, and can be adjusted according to the actual situation.

[0087] The microcatheter described in this application is relatively fixed between the body and blood vessels for a long time with very little displacement and minimal damage to the vascular endothelium. It does not cause thrombosis within 24 hours when placed in a vein, and it is not prone to thrombosis when placed in an artery for a long time. It is suitable for local administration of drugs to patients with head, liver, and coronary artery diseases through blood vessels, and is also suitable for local administration of chemotherapy drugs to cancer patients. Using it for local drug administration can reduce the dosage to less than 20% of the conventional dosage, avoiding the adverse effects of excessive drug administration on other organs and not affecting surgery on other organs.

[0088] The scope described above can be used alone or in combination. The following examples will make this application easier to understand.

[0089] Example

[0090] Example 1

[0091] This embodiment discloses a microcatheter for local drug delivery, such as... Figure 1 and Figure 2 As shown, it comprises, from proximal to distal, a delivery section 100, a fixing section 200, an opening section 300, and a distal section 400. The delivery section 100 is 1.1 m long. The delivery section 100, the fixing section 200, and the opening section 300 have a communicating inner cavity 110 with an outer diameter of 4F and an inner diameter of 1.0 mm. This size allows the microcatheter to be placed in the body for extended periods without causing hemolysis or other adverse reactions, and allows for drug delivery via a high-pressure infusion pump.

[0092] The distal segment 400 is 10 mm long and has a guidewire through-hole 610 to accommodate the guidewire for microcatheter placement and free movement within the blood vessel. The fixing segment 200 has a pre-formed arc shape with a height of 4 mm and a span of 20 mm. This shape is used to fix the microcatheter relative to the blood vessel after placement, preventing displacement of the microcatheter without affecting blood flow and facilitating local drug delivery. The end of the opening segment 300 is sealed, thus ensuring that the opening segment 300 and the distal segment 400 are properly aligned. The delivery segment 400 is not connected. Three first side openings 310 are provided on the outer periphery of the opening segment, allowing medication in the inner lumen 110 to reach the target area through the first side openings 310. A marker 320 is provided at the connection between the opening segment 300 and the fixing segment 200 to help external devices detect its position within the patient's body. A second side opening 210 is provided on the outer side of the arc-shaped top of the fixing segment 200, allowing anticoagulant medication to flow out through the second side opening 210, preventing thrombosis at this location and further optimizing the anticoagulant performance of the microcatheter. The delivery segment 100, fixing segment 200, and opening segment 300 comprise a metal wire inner layer and a polycarbonate outer layer, and the outer surface of the microcatheter is provided with an anticoagulant coating.

[0093] The microcatheter does not cause thrombosis within 24 hours when placed in a vein, and is not prone to thrombosis when placed in an artery for a long time. It is suitable for local administration of drugs to patients with head, liver, and coronary artery diseases via blood vessels, and is also suitable for local administration of chemotherapy drugs to cancer patients. It can reduce the dosage to less than 20% of the conventional dosage, reducing the damage of chemotherapy drugs to other parts of the body and organs.

[0094] Example 2

[0095] This embodiment discloses a medical device for local drug delivery in the coronary artery, referring to... Figures 3 to 12It includes a guide tube 700, a guide wire 600, an auxiliary wire 800, a Luer connector 900, and a microcatheter 10. The microcatheter 10 includes, from proximal to distal, an injection pump connector section 500, a delivery section 100, an opening section 300, a fixing section 200, and a distal section 400. The delivery section 100 is 1.3m long. The injection pump connector section 500, delivery section 100, opening section 300, and fixing section 200 have a communicating inner cavity 110. The outer diameter of the injection pump connector section is 3.5F, the outer diameter of the delivery section 100 and the opening section 300 is 2.6F, and the inner diameter of the inner cavity 110 is 0.6mm. The terminal section 400 is basically straight and 10mm long, allowing it to move freely in the blood vessel for easy microcatheter implantation. This size allows the microcatheter to be placed in the body for a long time without causing hemolysis or other adverse reactions, and allows drug delivery through a high-pressure injection pump tubing. The injection pump connector section 500 is made of polycarbonate material, and the delivery section 100 and the opening section 300 include a metal wire inner layer and a polycarbonate outer layer.

[0096] The fixing section 200 has a pre-formed arc shape with a height of 15mm and a span of 40mm. This arc shape fixes the microcatheter relatively within the blood vessel, with the top of the arc shape abutting against the vessel wall, preventing displacement of the microcatheter and ensuring unimpeded blood flow, thus facilitating local drug delivery. The overall shape of the microcatheter is as follows: Figure 3 As shown, the delivery section 100 and the terminal section 400 of the microcatheter form an angle of approximately 90 degrees, which allows for smoother delivery and placement in the coronary artery.

[0097] Reference Figure 4 The opening section 300 has a first side opening 310 every 120° at its starting point, allowing the medication in the lumen 110 to reach the target area through the first side opening 310. Markers 320 are provided at the junctions of the opening section 300 and the fixing section 200, and at the junctions of the opening section 300 and the delivery section 100, to help external devices detect their position within the patient's body.

[0098] The fixed section 200 has a second side opening 210 on the outer side of its arc-shaped top. The end of the fixed section 200 is sealed, so that the fixed section 200 is not connected to the end section 400, and the second side opening 210 on the outer side of the arc-shaped top is connected to the inner lumen 110. This allows anticoagulant drugs to flow out through the second side opening 210 on the outer side of the arc-shaped top, preventing thrombosis at this location. This further optimizes the anticoagulant performance of the microcatheter, making it less likely for thrombosis to form when the microcatheter is placed in the artery for a long time.

[0099] The terminal segment 400 is provided with a guidewire through hole 610, which is located downstream of the end blockage of the fixed segment 200. It can accommodate the guidewire for catheter placement. The microcatheter enters the blood vessel along the guidewire. The arc-shaped shape of the fixed segment 200 keeps the position between the microcatheter and the blood vessel relatively fixed.

[0100] The microcatheter has an anticoagulant coating on both its inner and outer surfaces. When placed in a vein, the microcatheter does not form a thrombus within 24 hours; when placed in an artery, it is less likely to form a thrombus even with prolonged placement. It is suitable for local drug delivery to patients with coronary artery disease, reducing the dosage to less than 20% of the conventional dosage and minimizing damage to other parts of the body and organs.

[0101] Figures 5 to 12 A schematic diagram of a microcatheter implanted in vivo using a medical device for local drug delivery is shown. The outer diameter of the guidewire 600 is smaller than the inner diameter of the guidewire through-hole 610. The outer diameter of the auxiliary wire 800 is larger than the inner diameter of the proximal end of the microcatheter 10. The outer diameter of the auxiliary wire 800 is smaller than the inner diameter of the guide tube 700, and the inner diameter of the guide tube 700 is larger than the outer diameter of the microcatheter 10. The distal end of the auxiliary wire 800 has an extended connecting section 810. The outer diameter of the extended connecting section 810 is smaller than the inner diameter of the proximal end of the microcatheter, allowing the extended connecting section 810 to be inserted into the proximal end of the microcatheter. Figure 5 As shown, first, guide wire 600 is set in the target area, and guide tube 700 is pushed to the target area, as follows. Figure 6 As shown, the distal end of the microcatheter 10 is pushed to the target area along the guidewire 600. Figure 7 It shows Figure 6 A partial schematic diagram of the microcatheter within the dashed box. (See attached diagram.) Figure 8 As shown, the distal extension 810 of the auxiliary wire 800 is inserted into the proximal end of the microcatheter, ensuring that the auxiliary wire 800 can stably abut against the proximal end of the microcatheter 10. The auxiliary wire 800 is used to hold the proximal end of the microcatheter 10 in vitro, as shown. Figure 9 As shown, with the help of the auxiliary wire 800, the guide tube 700 and guide wire 600 can be withdrawn without affecting the position of the microcatheter 10 in the body. Figures 10 to 12 As shown, after the guide tube and guidewire are removed, the fixed section of the microcatheter 10 returns to an arc shape, which allows the microcatheter to be stably placed in the coronary artery without causing too much displacement and without affecting blood flow. Figure 11This is a schematic diagram of a detachable Luer connector 900 and its connection to a microcatheter injection pump connector section 500. The detachable Luer connector 900 includes a female connector 910 and a male connector 920 that are threaded together. The female connector 910 has an extension 911, and the male connector 920 has an elastic fixing part 921. When connecting the microcatheter and the injection pump, the injection pump connector section 500 of the microcatheter is inserted into the male connector 920 of the through Luer connector, so that the injection pump connector section 500 passes through... During the interlocking process of the female connector 910 and the male connector 920 via the fixing part 921, the extension 911 inside the female connector 910 abuts against the fixing part 921 inside the male connector 920. As the Luer connector is further tightened, the extension 911 and the male connector 920 work together on the fixing part 921, causing the injection pump connector section 500 to be clamped and secured by the fixing part 921, thereby connecting one end of the microcatheter to the Luer connector, and the other end of the Luer connector to the pump tubing of the injection pump. By connecting the injection pump connector section 500 of the microcatheter 10 to the injection pump through the detachable Luer connector 900, the drug can directly reach the target area through the inner lumen of the microcatheter, achieving local drug delivery and reducing the dosage to less than 20% of the conventional dosage.

[0102] Animal studies have shown that when a second side opening is not provided on the outer side of the top of the arc-shaped portion of the fixed segment, the area where the microcatheter rests against the vessel wall is prone to thrombus formation, negatively impacting long-term placement of the microcatheter. This application addresses this issue by providing a second side opening on the outer side of the top of the arc-shaped portion of the fixed segment. This allows anticoagulant drugs to flow out through this opening, reducing thrombus formation in this area and further optimizing the anticoagulant properties of the microcatheter. Consequently, when the microcatheter is placed in an artery, thrombus formation is less likely to occur on either the vessel wall or the arterial wall.

[0103] Example 3

[0104] This embodiment discloses a microcatheter for local cerebrovascular drug delivery, which comprises, from proximal to distal, an infusion pump connector segment, a delivery segment, an opening segment, a fixation segment, and a distal segment. The delivery segment is 1.1 m long. The infusion pump connector segment, delivery segment, opening segment, and fixation segment have a communicating lumen. The outer diameter of the infusion pump connector segment is 5.5 F, the outer diameter of the delivery segment and the opening segment is 4 F, and the inner diameter of the lumen is 1.2 mm. The distal segment is substantially straight and 2 mm long, allowing it to move freely within the blood vessel for easy microcatheter implantation. This size allows the microcatheter to remain in the body for extended periods without causing hemolysis or other adverse reactions, and enables drug delivery via a high-pressure infusion pump. The delivery segment and the opening segment comprise a metal wire inner layer and a polycarbonate outer layer.

[0105] The overall shape of the microcatheter is as follows Figure 13As shown, the delivery section 100, the opening section 300, and the end section 400 are basically straight in the axial direction of the microcatheter. The fixing section 200 has a pre-formed arc shape with a height of 5 mm and a span of 10 mm. The arc shape fixes the microcatheter relatively in the blood vessel, so that the microcatheter does not shift and does not affect blood flow, which facilitates local drug delivery.

[0106] The fixed section is sealed near the distal end, thus preventing communication between the fixed section and the distal end. A first side opening is provided at the beginning of the perforated section, approximately 20mm from the distal end of the microcatheter, allowing medication within the lumen to reach the target area. A second side opening is provided on the outer side of the arc-shaped top of the fixed section 200, allowing anticoagulant medication to flow out through this opening, preventing thrombosis at this location, further optimizing the anticoagulant performance of the microcatheter, and making it less prone to thrombosis when placed in the artery for extended periods.

[0107] Markers are provided at the connection points between the opening section and the fixing section, and at the connection points between the opening section and the conveying section, to help external devices detect their position inside the patient's body.

[0108] The distal segment is provided with a guidewire through-hole, which can accommodate the guidewire for catheter placement. The microcatheter enters the blood vessel along the guidewire. The arc-shaped shape of the fixed segment 200 keeps the position between the microcatheter and the blood vessel relatively fixed. The displacement of the microcatheter is very small, does not damage the vascular endothelium, and does not affect blood flow.

[0109] The microcatheter has an anticoagulant coating on both its inner and outer surfaces, making it less prone to thrombosis when placed in cerebral blood vessels. During cerebral vascular stent implantation or anticoagulation therapy for cerebral infarction, the microcatheter is selectively inserted into cerebral blood vessels (2-4 mm in diameter). The infusion pump connector is fixed externally and connected to the anticoagulant drug, continuously pumping in anticoagulant or antiplatelet drugs. Due to selective infusion, the drug dosage is reduced to 1 / 20-1 / 5 of the systemic dose. For patients with bleeding or bleeding tendency, 2-15 days of non-anticoagulant / antiplatelet therapy can be achieved.

[0110] Example 4

[0111] This embodiment discloses a microcatheter for local liver drug delivery, which comprises, from proximal to distal, an infusion pump connector segment, a delivery segment, an orifice segment, a fixation segment, and a distal segment. The delivery segment is 1.2 m long. The infusion pump connector segment, delivery segment, orifice segment, and fixation segment have a communicating lumen. The outer diameter of the infusion pump connector segment is 5.5 F, the outer diameter of the delivery segment and the orifice segment is 5 F, and the inner diameter of the lumen is 1.5 mm. The distal segment is substantially straight and 20 mm long, allowing it to move freely within a blood vessel for easy microcatheter implantation. This size allows the microcatheter to remain in the body for extended periods without causing hemolysis or other adverse reactions, and enables drug delivery via a high-pressure infusion pump. The delivery segment and the orifice segment comprise a metal wire inner layer and a polycarbonate outer layer.

[0112] The overall shape of the microcatheter is the same as that in Example 3. The fixed section has a pre-formed arc shape with a height of 6 mm and a span of 12 mm. The arc shape fixes the microcatheter relatively in the blood vessel, so that the microcatheter does not shift and does not affect blood flow, which facilitates local drug delivery.

[0113] The fixed section is sealed near the distal end, preventing communication between the fixed and distal sections. A first side opening is located at the beginning of the perforated section, approximately 40mm from the distal end of the microcatheter, allowing medication within the lumen to reach the target area. A second side opening is located on the outer side of the curved top of the fixed section, allowing anticoagulant medication to flow out through this opening, preventing thrombosis at this location and further optimizing the anticoagulant properties of the microcatheter, making it less prone to thrombosis even when placed in an artery for extended periods.

[0114] Markers are provided at the connection points between the opening section and the fixing section, and at the connection points between the opening section and the conveying section, to help external devices detect their position inside the patient's body.

[0115] The distal segment is provided with a guidewire through-hole, which can accommodate the guidewire for catheter placement. The arc-shaped shape of the fixed segment 200 keeps the position of the microcatheter relative to the blood vessel, and the displacement of the microcatheter is very small, so as not to damage the vascular endothelium or affect blood flow.

[0116] The microcatheter has an anticoagulant coating on both its inner and outer surfaces, making it less prone to thrombosis when placed in hepatic blood vessels. During chemotherapy in cancer patients, such as those with liver cancer, the microcatheter can be selectively inserted into the tumor's blood supply vessel (selecting a specific hepatic lobe artery) to deliver selectively pumped chemotherapy drugs, achieving the effects of local chemotherapy or selective chemoresection. Because of the selective pump delivery, the total chemotherapy dose can be reduced to 1 / 20 to 1 / 10 of the original dose, significantly reducing chemotherapy side effects.

[0117] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure, which is determined by the appended claims.

Claims

1. A microcatheter for local drug delivery, comprising, from proximal to distal: Conveying section, stationary section, perforated section, and end section. The conveying section, fixing section, and opening section have a communicating inner cavity with an outer diameter of 1.5F to 5F and an inner diameter of 0.40 mm to 1.5 mm. The length of the end section is 1 to 40 mm, and it is provided with a guide wire through hole; The fixing section has a pre-formed arc shape, which is used to fix the position between the microcatheter and the blood vessel by means of the shape after the microcatheter is set; The end of the opening section is sealed, thus preventing the opening section from communicating with the end section. The opening section is provided with a first side opening, and a marker is provided near the opening section, specifically at the connection between the opening section and the fixing section, to help external devices detect their position in the patient's body; The fixed section has a second side opening on the outer side of its arc-shaped top. The outer surface of the microcatheter is coated with an anticoagulant coating. The arc-shaped profile has a bow height of 2mm to 40mm and a span of 2mm to 60mm.

2. The microcatheter for local drug delivery according to claim 1, wherein the length of the distal segment is 6 mm to 20 mm, and wherein the outer diameter of the delivery segment, the fixation segment, and the opening segment is 1.7F to 4F, or 1.7 to 2.6F, and the inner diameter is 0.45 mm to 1.2 mm.

3. The microcatheter for local drug delivery according to claim 1, wherein the length of the delivery segment is 0.4 to 1.5 m, 0.7 to 1.3 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

4. A microcatheter for local drug delivery, comprising, from proximal to distal: Conveying section, opening section, fixing section, and end section. The conveying section, the opening section, and at least part of the fixing section have communicating internal cavities with an outer diameter of 1.5F to 5F and an inner diameter of 0.40mm to 1.5mm. The end segment is substantially straight and has a length of 1 to 40 mm; The fixing section has a pre-formed arc shape, which is used to fix the position between the microcatheter and the blood vessel by the shape after the microcatheter is installed, while the straight end section is free in the blood vessel. The opening section is provided with a first side opening, and a marker is provided near the opening section, specifically at the connection between the opening section and the fixing section and / or at the connection between the opening section and the conveying section, to help the external device detect its position in the patient's body; The fixed section has a second side opening on the outer side of its arc-shaped top. The fixed section or the end section is blocked, so that the fixed section and the end section are not connected. The blocking point is located downstream of the second side opening on the outer side of the arc-shaped top, so that the second side opening on the outer side of the arc-shaped top is connected to the inner cavity. The end section and the fixed section are provided with guide wire through holes, which are located downstream of the blocking point. The outer surface of the microcatheter is coated with an anticoagulant coating. The arc-shaped profile has a bow height of 2mm to 40mm and a span of 2mm to 60mm.

5. The microcatheter for local drug delivery according to claim 4, wherein the length of the distal segment is 6 mm to 20 mm, and the outer diameter of the delivery segment and the orifice segment is 1.7F to 4F, or 1.7 to 2.6F, and the inner diameter is 0.45 mm to 1.2 mm.

6. The microcatheter for local drug delivery according to claim 4, wherein the length of the delivery segment is 0.4 to 1.5 m, 0.7 to 1.3 m, 0.8 to 1.3 m, or 1.1 to 1.3 m.

7. A medical device for local drug delivery, comprising a guide tube, a guidewire, an auxiliary tube, a detachable Luer connector, and a microcatheter according to any one of claims 1-6, wherein the inner diameter of the auxiliary tube is smaller than the outer diameter of the proximal end of the microcatheter, the outer diameter of the guidewire is smaller than the inner diameter of the guidewire through-hole, the outer diameter of the auxiliary tube is greater than or equal to the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube is greater than the outer diameter of the microcatheter, such that the guide tube, after being used to assist in the placement of the guidewire and microcatheter, can be withdrawn with the assistance of the auxiliary tube, leaving the microcatheter in the human body.

8. A medical device for local drug delivery, comprising a guide tube, a guidewire, an auxiliary wire, a detachable Luer connector, and a microcatheter according to any one of claims 1-6, wherein the outer diameter of the guidewire is smaller than the inner diameter of the guidewire orifice, the outer diameter of the auxiliary wire is larger than the inner diameter of the proximal end of the microcatheter, and the inner diameter of the guide tube is larger than the outer diameter of the microcatheter, such that the guide tube, after being used to assist in the placement of the guidewire and microcatheter, can be withdrawn with the assistance of the auxiliary wire, leaving the microcatheter in the human body.

9. The medical device for local drug delivery according to claim 8, wherein the distal end of the auxiliary wire has an extended connecting segment, the outer diameter of the extended connecting segment being smaller than the inner diameter of the proximal end of the microcatheter, thereby allowing the extended connecting segment to be inserted into the proximal end of the microcatheter.

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