Flexible intravascular targeted delivery catheter

Abstract

The invention relates to a flexible intravascular targeted delivery catheter which comprises a guide wire rapid exchange section, a puncture needle sheath and a catheter body which are connected in sequence. The guide wire rapid exchange section is located at the front end of the puncture needle sheath, a guide wire exchange channel of a micro guide wire is axially arranged in the guide wire rapid exchange section, and an inlet of the guide wire exchange channel is formed in the side wall of the end, close to the puncture needle sheath, of the guide wire rapid exchange section. A conveying pipe is arranged in the catheter body, and the front end of the conveying pipe is connected with three puncture needles which are evenly distributed in the circumferential direction and located in the puncture needle sheath. Three puncture needle outlets are evenly distributed in the side wall of the front portion of the puncture needle sheath in the circumferential direction. The side wall of the rear portion of the catheter body is connected with a side edge infusion tube, the rear end of the catheter body is connected with a puncture needle pushing device which drives the conveying tube to achieve forward pushing and backward withdrawing of the puncture needle, and the rear end of the conveying tube penetrates out of the rear end of the puncture needle pushing device and is provided with a tail end connector. The catheter can effectively overcome the inherent defects of most intravascular delivery catheters, and the performance quality of the intravascular delivery catheter and the effectiveness and practicability of clinical application are remarkably improved, so that the catheter shows more excellent technical advantages and clinical value in the field of vascular interventional diagnosis and treatment.

Description

Technical Field

[0001] The invention relates to a flexible intravascular targeted delivery catheter. Background Art

[0002] Natural pathways within the human body, such as the blood vessels, digestive tract, respiratory tract, and urogenital tract, are considered preferred routes for delivering therapeutic drugs due to their inherent advantages. In clinical practice, access to these pathways is often achieved through puncture or endoscopic guidance. Combined with precision drug delivery technologies, this approach can significantly enhance clinical efficacy. Among these pathways, blood vessels are the most commonly used and critical drug delivery pathway due to their widespread distribution, systemic reach, and unrestricted access to organs and tissue structures. Devices such as intravascular catheters, balloons, and intravascular delivery systems with puncture needles play a crucial role in this process. In the treatment of vascular and neoplastic lesions, this approach, which delivers drugs directly to the targeted site and provides localized, precise treatment, effectively overcomes the limitations of traditional drug delivery methods, significantly improving clinical efficacy while reducing the incidence of systemic side effects. In recent years, with the rapid advancement of biomedical engineering and drug delivery technologies, a variety of methods and devices for localized intravascular drug delivery have emerged, providing a richer and more effective treatment option for related diseases.

[0003] (I) Application in vascular lesions 1. Traditional catheter-based interventional therapy: As an important diagnostic and treatment approach for vascular diseases, traditional vascular interventional therapy relies on precisely delivering a catheter to the target vessel via an intravascular channel system, followed by localized drug infusion or embolization. This technology, with its minimally invasive nature and targeted advantages, has become a standardized procedure in clinical practice. It has demonstrated exceptional clinical value in transcatheter arterial chemoembolization (TACE) for solid tumors, such as hepatocellular carcinoma, and has become the most mature and evidence-based core treatment modality in the field of tumor interventional therapy.

[0004] However, this technology still has significant limitations in drug delivery. While therapeutic drugs can achieve a certain degree of drug accumulation within target organs via the first-pass effect after catheter infusion, the retention of drug molecules in the lesion region exhibits an exponential decline due to the permeability of the vascular endothelium and hemodynamic washout. Pharmacokinetic studies have shown that effective drug concentrations in local interstitial fluid typically persist for no more than two hours. This short exposure period is insufficient to meet the biological requirements for sustained inhibition of tumor cell proliferation or induction of vascular remodeling. More critically, in the treatment of benign vascular lesions such as coronary atherosclerosis or peripheral arterial stenosis, conventional liquid drug formulations generally exhibit transendothelial transport efficiencies below 5% due to limitations in their surface charge, lipophilicity, and binding to the extracellular matrix of the vascular wall. This makes it difficult for many drugs that demonstrate significant antiproliferative or anti-inflammatory effects in vitro to achieve effective bioavailability at the target site.

[0005] It is noteworthy that the drug delivery deficiencies of current interventional therapy systems have spawned multiple clinical challenges. Systemic drug diffusion not only reduces local therapeutic efficacy (bioavailability is typically less than 20%) but can also induce dose-dependent myelosuppression or organ toxicity. Furthermore, the mechanical clearance of drugs attached to the vessel wall by blood flow shear forces, combined with the drug permeation barrier caused by endothelial dysfunction in diseased vessels, constitute key pathophysiological obstacles limiting the expansion of interventional therapy into benign vascular diseases. Overcoming these mechanistic deficiencies urgently requires the collaborative innovation of novel drug carrier systems and precision delivery technologies.

[0006] 2. Drug-Coated Balloon: As an innovative solution, drug-coated balloon (DCB) technology has emerged. DCBs utilize a specialized catheter design with nanoporous distal surface treatment and a therapeutic drug-excipient composite coating (drug density 3-5 μg / mm²). This technology achieves targeted drug delivery to the vessel wall through mechanical-fluidic coupling during balloon expansion. For example, in coronary intervention, mTOR inhibitors (such as rapamycin) or microtubule stabilizers (such as paclitaxel) coated on the balloon surface can act on medial smooth muscle cells through a dual mechanism of passive diffusion and active intercalation upon contact with the lesioned vessel wall, increasing the proportion of cell cycle arrest in the G1 phase to approximately 70%. This significantly reduces the incidence of restenosis six months after surgery compared to conventional bare balloon angioplasty. This technology has been expanded to clinical interventions for peripheral vascular lesions such as lower limb arteries (Fontaine stages IIb-IV), renal arteries (stenosis >70%), and subclavian arteries.

[0007] Compared to traditional bare metal stents (BMS) and drug-eluting stents (DES), the core advantage of DCBs lies in their "invasive, non-implantable" nature. They deliver therapeutic effects through a single pulsed release of drug (half-life approximately 30 seconds), avoiding long-term complications such as late stent thrombosis and stent fracture caused by permanent foreign body retention. However, DCB technology still faces two technical bottlenecks: First, the drug coating is susceptible to fluid shear forces and vessel wall contact pressure during balloon delivery, resulting in 20-35% of the drug being released prematurely before reaching the target site. Second, due to limitations in existing sustained-release technologies, the effective drug concentration within the vessel wall is maintained for only approximately four weeks, making it difficult to treat complex lesions with diffuse and / or severe calcification.

[0008] 3. Microporous Balloon: Aiming to address the need for precision treatment of vascular stenosis / occlusion, a research team has innovatively developed the Porous Topological Balloon Delivery System (PTBDS). This device, based on a biomimetic reconstruction of the traditional balloon structure, replaces the traditional closed bladder cavity with a porous foam topology (porosity 65%-80%, pore size 10-50μm). Its Young's modulus (0.5-2.0 MPa) is 40%-60% lower than that of conventional balloons, significantly improving the contact stress distribution on the vessel wall. Its core working mechanism relies on microfluidics: when the balloon is inflated at a pressure of 0.5-3 atm, the therapeutic agent (drug / stem cell suspension) penetrates the vessel wall through micron-sized through-pores (at a flow rate of 0.1-0.5 mL / min), achieving targeted penetration into the tunica media (300-500μm). Experimental studies have shown that when using PTBDS to deliver mesenchymal stem cells, regulating pore geometry can increase cell attachment efficiency to approximately 80%, and activate related signaling pathways to achieve an endothelial differentiation rate of approximately 42%. However, due to fluid shear stress (>15 dyn / cm²) and a lack of extracellular matrix anchoring sites, the transplanted cells lose over 90% after 72 hours, limiting their revascularization performance.

[0009] This technology also presents hemodynamic challenges: complete blood flow occlusion during balloon inflation (often limited to 90 seconds in coronary applications) can lead to an increase in myocardial ischemia score (TIMI frame rate) to 28 ± 5 frames (normal value < 13 frames), and a 3.2-fold increased risk of induced ventricular arrhythmias. To balance efficacy and safety, an intermittent inflation strategy (30-second inflation / 60-second perfusion alternation) is often used in clinical practice, but this can reduce drug penetration efficiency by approximately 40%.

[0010] 4. Microneedle catheter: In terms of clinical operation, there are two main approaches to enhance drug penetration and prolong its local retention time. The first approach is to re-modify the drug itself and load it with auxiliary active ingredients that can enhance permeability / penetration performance. However, because these auxiliary ingredients may have potential inhibitory and weakening effects on the target drug, or even destroy the original physical, chemical and biological properties of the drug, this method is difficult to implement and its efficacy is difficult to guarantee. The second approach is to directly inject the drug into the local area where intervention treatment is required through a catheter with a micropuncture needle. This method is direct and simple to operate, and can accurately and targetedly release the drug into the blood vessel wall or perivascular tissue, while prolonging the local retention time of the drug, and has high clinical feasibility.

[0011] For example, a study has developed a smart microneedle-coated balloon catheter (MNBC) based on the concealing and expansion-contraction properties of pufferfish bones. This catheter consists of three layers: a gelatin layer containing black phosphorus (BP), a drug-carrying microneedle layer, and another gelatin layer containing BP. In the uninflated state, the microneedles are concealed beneath the outermost protective gelatin layer, making the catheter surface relatively smooth and facilitating intravascular movement. Upon reaching the target site, BP is irradiated with near-infrared (NIR) light, converting light energy into heat, melting the gelatin layer, exposing the microneedles and allowing them to penetrate the blood vessel wall. Simultaneously, the melting of the innermost gelatin layer allows the microneedles to detach from the balloon catheter and remain within the blood vessel wall, achieving sustained drug release. The advantages of the MNBC lie in its responsiveness, penetration capability, and biosafety. Through an NIR-triggered thermal response mechanism, precise drug release and controlled microneedle exposure are achieved. The microneedle design enables it to penetrate the blood vessel wall, delivering drugs directly to the lesion site, enhancing local drug concentration and therapeutic efficacy. In addition, the detachment function of the microneedles prolonged the drug release time, further enhancing the therapeutic effect.

[0012] However, MNBC also faces several challenges. First, the concentration of BP and the NIR power have a significant impact on temperature rise, requiring precise control to ensure safety and effectiveness. Second, the mechanical strength and penetration ability of the microneedles need to be further optimized to meet the needs of different types of vascular lesions. Furthermore, the biocompatibility and degradation properties of BP and gelatin require further research to ensure long-term safety.

[0013] Based on this concept, a variety of microneedle puncture catheter devices have been used for various tests. For example, Binlab retractable microneedle catheter, see Figure 1 . Figure 1Center: This catheter utilizes over-the-wire (OTW) technology for guidance. Three micropuncture needles (yellow arrows) spaced 120 degrees apart extend through the catheter's side holes, piercing the vessel wall and injecting medication (red arrows). This catheter is advanced to the localized blood vessel via a centrally positioned guidewire. Three internally positioned micropuncture needles, each with a memory function, penetrate the vessel wall with a nickel-titanium alloy needle, achieving localized medication delivery.

[0014] Another type of needle injection catheter, NIC, is used to inject liquid drugs and stem cells into the myocardium to repair damaged myocardium. Figure 2 . Figure 2 Middle: A. Three micropuncture needles spaced 120° apart are pushed out of the catheter from the tip (yellow arrow); B. Microneedles are pushed through the spiral pusher at the end of the catheter (red arrow); X-ray fluoroscopy shows the catheter being pushed through the guide tube into the heart, where the micropuncture needles are deployed and the drug is injected (yellow arrow); D. An enlarged view of the catheter tip under X-ray fluoroscopy shows that the contrast agent injected by the puncture needles enters the myocardium and produces an irregular diffusion area (circular yellow dashed line); E. Dissected animal heart shows the puncture needles piercing the myocardium; F. In the in vitro heart model, the catheter is extended through the guide tube into the "heart cavity", and the micropuncture needles are also extended.

[0015] To use this catheter, a larger-diameter guide tube is first inserted. Once the catheter reaches the target area, the microneedle is then inserted through the guide tube. The microneedle is then pushed out through the screw-in mechanism at the end, piercing the target tissue for injection and treatment. Consequently, its intravascular superselectivity is poor, making it difficult to access tortuous and small blood vessel branches.

[0016] There are also similar puncture catheters that are used to inject liquid ablative agents into the renal artery to damage the nerves around it and thus achieve the purpose of treating renal hypertension. Figure 3 . Figure 3 Middle: A. The catheter is inserted using over-the-wire (OTW) technology. B. A micropuncture needle penetrates the renal artery and injects ethanol to damage the conductive nerves surrounding the renal artery.

[0017] The front end of the injection catheter is equipped with three micro-puncture needles, each needle is 120 degrees apart from each other. After the catheter is pushed out, it punctures the renal artery and enters the vascular adventitia. Anhydrous ethanol is injected to damage the sympathetic nerves around the renal artery, blocking the mechanical and chemical stimulation signals of the kidney from being transmitted to the central nervous system, reducing sympathetic nerve tension, and dilating small arteries throughout the body, thereby achieving the purpose of lowering blood pressure.

[0018] Based on the same device, the channel catheter microneedle can also be used to inject therapeutic functions and artificially modified, separated, purified and modified cell components into the tissue area that needs treatment, which can also improve the efficiency of local retention, penetration and transfection.

[0019] 5. Microneedle balloon catheter. The design of this catheter combines the characteristics of a balloon and a microneedle, combining the two to achieve the purpose of penetrating blood vessels for local injection. Figure 4 . Figure 4 Middle: AB. The eccentrically designed balloon is folded together (white arrow), and the micropuncture needle is wrapped; when the balloon is inflated and opened, the micropuncture needle is released (yellow arrow) and penetrates the target area for drug injection.

[0020] The key feature of this design lies in the combination of a balloon and microneedles: the balloon is designed to be foldable, enclosing a channel containing multiple microneedles. When the catheter reaches the target area and inflates the balloon, the microneedles are pushed out to the surface of the balloon, where they penetrate the blood vessel wall and inject therapeutic drugs. Similarly, stem cells, genes, and other therapeutic agents can also be injected to achieve specific localized treatment goals.

[0021] (II) Application in tumorous lesions All of the above-mentioned devices and instruments are used in tumor treatment for the targeted delivery of chemotherapy drugs, molecular targeted drugs, ablative agents, gene drugs, etc., and have also achieved certain clinical therapeutic effects.

[0022] In summary, there is a huge demand for targeted intravascular delivery therapy in clinical practice, and the invention of many catheter devices has preliminarily verified the feasibility and clinical efficacy of the solution. However, there is still a huge room for iteration and upgrading of existing solutions. For example: 1. The catheter's low flexibility makes it difficult to navigate tortuous and delicate vessels to reach deeper areas requiring treatment. The aforementioned over-the-wire (OTW) catheter, designed with three microneedles and a separate central guidewire channel for a total of four channels, is relatively rigid and lacks flexibility. Therefore, it is only suitable for primary aortic branches and has difficulty accessing secondary branches, distal vessels, and anatomically tortuous lesions.

[0023] The puncture needle has weak puncture ability. Because most micropuncture needles need to maintain their expanded state without deforming during retraction, they are typically made of a metal material with a memory function, such as nickel-titanium alloy. This metal does have a clear advantage in maintaining its original preformed shape, but the material itself is relatively soft. Micropuncture needles made of this material have difficulty penetrating tougher vascular structures, especially those in areas with atherosclerosis, resulting in unsatisfactory clinical results.

[0024] The number and distribution of puncture needles are insufficient. Some balloons wrap around the micropuncture catheter because the balloon has only a single folding direction. Therefore, when the balloon is deployed, injection can only be performed in a single direction, and there is no guarantee of a uniform circular distribution around the target blood vessel, which affects the efficacy. Secondly, the balloon needs to be fully inflated during injection so that the micropuncture needle can penetrate the blood vessel with the help of the balloon's expansion force. However, filling the balloon can cause blood flow blockage, which can cause myocardial ischemia and even induce arrhythmias and myocardial infarction during coronary artery treatment. Therefore, this device is not a perfect solution.

[0025] The catheter diameter is too large. Similar to the first point, multiple minimally invasive needles are coaxial with the guidewire (over-the-wire, OTW) channel, resulting in a larger-caliber catheter design and manufacture, making it difficult to access smaller vessels. In patients with coronary artery ischemia or infarction, the lesions are often located deep within the distal coronary arteries, where the vessels branch thinner. This large-caliber catheter has difficulty reaching distal locations, making it less than ideal for delivering isolated and purified stem cells, virally transfected stem cells, gene therapies, and sustained-release drugs.

[0026] Balloon design flaws. All intravascular delivery devices developed based on the balloon expansion principle require temporary blood flow occlusion (usually lasting 60-180 seconds) when inflating the balloon. In clinical practice, although this operation is relatively short, it can easily trigger drastic changes in endothelial shear stress for vascular stenosis lesions that already have insufficient blood supply and are in a critical state of hemodynamic compensation (FFR of 0.75-0.80), significantly increasing the risk of iatrogenic vascular injury by 2.8-3.5 times. Therefore, balloon-based intravascular delivery devices have certain design flaws, which should be given full attention in clinical applications and measures such as optimizing operating procedures, reducing the frequency of use, and shortening the occlusion time should be adopted as much as possible to avoid the occurrence of iatrogenic injury.

[0027] Lack of real-time monitoring function design for angiography channels. Currently, the research and development of various intravascular delivery devices and equipment are mostly focused on the optimization of injection and delivery efficiency, but there are obvious technical shortcomings in the key area of intraoperative dynamic evaluation and real-time monitoring. The lack of this function may lead to potential medical risks in clinical practice. From a technical perspective, real-time angiography during surgery is an effective solution that can accurately complete dynamic evaluation and real-time monitoring, and can timely and accurately grasp the morphological characteristics of blood vessels, such as pathological conditions such as vascular dissection, thrombosis, and vascular spasm, thereby providing clinicians with a basis for timely intervention, which has significant advantages in improving surgical safety and effectiveness. Therefore, the delivery device is equipped with an intraoperative angiography channel, which has extremely important clinical application value.

[0028] However, 92% of devices lack integrated intraoperative angiography channels, forcing the operator to perform digital subtraction angiography (DSA) after the procedure is complete, inserting a dedicated angiography catheter via a catheter exchange (taking 3-5 minutes). During this time, the missed detection rate for new vascular dissections or acute thrombosis can be as high as 15-21%. This delayed, retrospective angiography method makes it difficult to promptly detect and effectively resolve acute complications such as vascular obstruction during drug injection and delivery, thus posing significant medical risks in clinical practice. Because existing technologies struggle to strike a reasonable balance between optimal performance and safety, many intravascular delivery devices, despite undergoing a complex R&D process, still face significant challenges in clinical translation and widespread application. Summary of the Invention

[0029] The purpose of the present invention is to provide a flexible intravascular targeted delivery catheter that can effectively overcome the inherent defects of most intravascular delivery catheters and significantly improve the performance quality of intravascular delivery catheters as well as the effectiveness and practicality of clinical applications.

[0030] The technical solution of the present invention is: a flexible intravascular targeted delivery catheter, comprising a guidewire quick exchange section, a puncture needle sheath, and a catheter body connected in sequence; the guidewire quick exchange section is located at the front end of the puncture needle sheath, and a guidewire exchange channel for a microguidewire is axially arranged in the guidewire quick exchange section, and the entrance of the guidewire exchange channel is arranged on the side wall of one end of the guidewire quick exchange section close to the puncture needle sheath; a delivery tube is arranged in the catheter body, and the front end of the delivery tube is connected to three puncture needles evenly arranged in the circumferential direction and located in the puncture needle sheath; the front side wall of the puncture needle sheath is evenly arranged with three puncture needle outlets along the circumferential direction; the rear side wall of the catheter body is connected to a side perfusion tube, and the rear end of the catheter body is connected to a puncture needle pushing device that drives the delivery tube to push and retract the puncture needle, and the rear end of the delivery tube passes through the rear end of the puncture needle pushing device and is provided with a tail end interface.

[0031] Furthermore, the rear portion of the guidewire quick exchange section has an arc-shaped connecting portion connected to the puncture needle sheath so that the axis of the guidewire exchange channel and the axis of the catheter body are not on the same axis.

[0032] Furthermore, the three puncture needle outlets are evenly distributed on the front side wall of the puncture needle sheath at an interval of 120 degrees. The puncture needles are in an outward arc shape. The three puncture needles are connected to the delivery tube through the puncture needle-delivery tube connection part in the catheter body cavity.

[0033] Furthermore, a guide cone is provided in the puncture needle sheath and at the rear end position near the puncture needle outlet, and three guide cone peep holes are axially provided on the guide cone and are evenly distributed in the circumferential direction and used for the puncture needle to pass through. The guide cone peep holes are inclined outward from the back to the front.

[0034] Furthermore, the puncture needle pushing device includes a tube body connected to the rear end of the catheter body, and a pushing slider is slidably connected to the tube body. The pushing slider has an intermediate connecting portion that penetrates the tube body and is fixed to the outer wall of the delivery tube, and a matching sliding limiting structure is provided between the pushing slider and the outer wall of the tube body.

[0035] Furthermore, the sliding limiting structure includes a left limiting groove and a right limiting groove arranged on the left and right side walls of the tube body, and the left and right inner walls of the pushing slider are correspondingly provided with guide keys that cooperate with the mortise and tenon of the left limiting groove and the right limiting groove.

[0036] Furthermore, the top and bottom of the tube body are correspondingly provided with an upper guide rail groove and a lower guide rail groove, and the intermediate connecting part passes through the upper guide rail groove and the lower guide rail groove and is fixedly connected to the conveying pipe; the surfaces of the limit groove and the guide rail groove are both provided with a scale in mm.

[0037] Furthermore, the middle connecting portion is made of a polymer material and is tightly connected to the delivery pipe; and an anti-slip push button is provided on the top of the pushing slider.

[0038] Furthermore, the front outer wall of the guidewire quick exchange section is wrapped with a radiopaque front metal marker ring, and the front and rear outer walls of the puncture needle sheath are correspondingly wrapped with a radiopaque middle metal marker ring and a rear metal marker ring.

[0039] Furthermore, the delivery tube and puncture needle are both made of medical steel 440, and the tail end interface is coated with a polymer material layer; an infusion tube base is fixed to the rear side wall of the catheter body, and the side infusion tube is connected to the catheter body through the infusion tube base.

[0040] Compared with the prior art, the present invention has the following advantages: 1. This flexible intravascular targeted delivery catheter is suitable for clinical medicine, ischemic / tumor diseases, atherosclerosis, coronary heart disease, myocardial infarction, and vascular interventional treatment.

[0041] 2. Traditional micropuncture needle catheters mostly use a single needle structure, which can only inject drugs from a single direction. It is difficult to achieve uniform distribution of drugs in the tissues around blood vessels, thus limiting the therapeutic effect of the drugs.

[0042] The present invention adopts a multi-needle design with three micropuncture needles, evenly arranged at 120° intervals, which can ensure the uniform distribution of drugs within the blood vessel wall and surrounding tissues and realize local drug injection. For most dose-dependent therapeutic drugs, this design can significantly improve the efficacy of the drugs and optimize the treatment effect.

[0043] 3. Conventional intravascular puncture and injection catheters use an over-the-wire (OTW) design, where the guidewire and catheter are in the same channel. This results in a thicker and harder catheter, making it difficult to manipulate rotation and increasing manufacturing difficulty.

[0044] The flexible intravascular targeted delivery catheter of the present invention adopts a guidewire rapid exchange channel. (1) The catheter can be quickly introduced into the target area of the lesion, simplifying the difficulty of operation. (2) The caliber of the catheter body is reduced to avoid the coaxial arrangement of the puncture needle and the guide wire. (3) The rapid exchange channel and the catheter body are not arranged in parallel. This distributed structural design can effectively reduce the overall outer diameter of the catheter. The smaller outer diameter not only facilitates the smooth entry of the catheter into blood vessels with smaller calibers, but also significantly reduces the difficulty of manufacturing the catheter. (4) During the treatment process, the micro-guidewire can remain in place. Once complications such as vascular spasm, dissection, and obstruction occur, and other interventional devices are required for auxiliary treatment, the micro-guidewire has a small caliber and can be well matched with most treatment devices, thereby facilitating rapid exchange operations and effectively eliminating complications that occur during the treatment process.

[0045] 4. Traditional injection catheter designs typically utilize over-the-wire (OTW) technology or lack a guidewire mechanism entirely (e.g., the NIC catheter). In this design, multiple metallic delivery catheters are coaxially arranged with the catheter sheath and guidewire, significantly increasing the overall catheter outer diameter. This large outer diameter limits its applicability for endovascular procedures, restricting it to treatment of large vessels such as primary aortic branches. Interventions into secondary branches or smaller vessels are difficult.

[0046] The present invention utilizes a single-channel delivery catheter design, significantly reducing the difficulty of catheter manufacturing, avoiding the complexities of multi-channel fabrication, and effectively reducing the catheter's outer diameter. While optimizing the catheter structure, it also ensures its flexibility, enabling it to accommodate the needs of intravascular treatment of secondary branches of large vessels and smaller vessels of comparable caliber. This approach effectively overcomes the shortcomings of most intravascular delivery catheters while retaining the advantages of existing catheters, thereby improving catheter quality and clinical efficacy, and expanding the application scope of intravascular treatment.

[0047] 5. Traditional balloon catheters require inflating the balloon to deploy a micropuncture needle, which then penetrates the blood vessel for injection. However, balloon inflation can block blood flow, leading to distal ischemia. If the treated vessel is already stenotic or obstructed, this blockage can further exacerbate distal ischemia, such as in the coronary arteries of the heart, potentially leading to unnecessary surgical complications.

[0048] The flexible intravascular targeted delivery catheter of the present invention does not need to block blood flow when reaching the target area for injection treatment, and can maintain continuous blood flow, thereby avoiding distal ischemia and related complications caused by blocking blood flow.

[0049] 6. Traditional intravascular injection catheters often use nickel-titanium alloy memory metal to maintain the puncture needle's curvature and outward extension at nearly its full length (approximately 100 cm). However, nickel-titanium alloy is relatively soft, making the needle tip difficult to sharpen, resulting in poor penetration of atherosclerotic plaques and fibrous tissue. Even with the needle fully extended, it often struggles to penetrate the vessel wall, hindering drug extravasation. Given the limited volume of the vascular wall, excessive fluid injection can easily lead to hematoma, rupture of the vascular muscular layer, and even dissecting aneurysms, leading to serious complications such as vascular stenosis, obstruction, and ischemia.

[0050] The present invention uses medical high-strength 440 steel, which is tougher than nickel-titanium alloy, to manufacture micropuncture needles. These needles have the advantages of a sharp tip, tough material, and strong penetrating power, making them capable of penetrating even tough lesions. This effectively overcomes the defects of existing catheter materials and improves the safety and effectiveness of intravascular injections. Furthermore, the guide cone within the puncture needle sheath has a unique structure. Its three guide cone peepholes extending forward and outward can precisely guide the three micropuncture needles to the exit and eject them. The advantages of this guide cone design are: on the one hand, it fully utilizes the forward thrust to ensure that the puncture needle effectively penetrates the blood vessel wall; on the other hand, it makes it possible to use ordinary medical steel to manufacture tough puncture needles, avoiding the use of preformed nickel-titanium alloy (which is softer and less sharp), thereby significantly improving puncture efficiency.

[0051] 7. The lateral perfusion channel enables real-time dynamic monitoring of the entire injection procedure using angiography, allowing simultaneous implementation of therapeutic interventions. This novel endovascular treatment device, with its independent lateral perfusion channel and injection delivery tube, allows for simultaneous intravascular injection and continuous infusion of contrast agent through the lateral perfusion channel for angiography. This innovative design enables real-time dynamic monitoring of vascular morphology (including abnormalities such as dissection, thrombosis, and vasospasm), providing a reliable basis for precise manipulation and timely optimization of treatment plans. Furthermore, the device allows for direct drug injection and other therapeutic interventions through the lateral perfusion channel, achieving simultaneous intravascular diagnosis and treatment, effectively avoiding the delayed diagnosis and iatrogenic risks associated with conventional endovascular delivery devices due to their lack of real-time angiography. This device achieves a reasonable balance between optimal performance and safety, facilitating future clinical translation and widespread application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Schematic diagram of Binlab's retractable microneedle catheter; Figure 2 Schematic diagram for the use of NIC injection catheter; Figure 3 Schematic diagram of the Peregrine perfusion catheter system; Figure 4 Schematic diagram of a microneedle balloon catheter; Figure 5 1 is an external view of the flexible intravascular targeted delivery catheter of the present invention in the needle-retracted state, wherein: A is a side view, B is a top view, and C is a bottom view; Figure 6 This is a cross-sectional view of the flexible intravascular targeted delivery catheter of the present invention (midsagittal plane in the needle-retracted state); Figure 7 For the present invention Figure 6 Cross-section from a1 to a8; Figure 8 For the present invention Figure 6 Cross-section from a9 to a13; Figure 9 For the present invention Figure 6 Enlarged view of area D in the middle; Figure 10 This is a cross-sectional view of the flexible intravascular targeted delivery catheter of the present invention (mid-level plane in the needle-retracted state); Figure 11 For the present invention Figure 10 Magnified view of area E in ; Figure 12 1 is an external view of the flexible intravascular targeted delivery catheter of the present invention in the needle-out state, wherein: A is a side view, B is a top view, and C is a bottom view; Figure 13 This is a cross-sectional view of the flexible intravascular targeted delivery catheter of the present invention (mid-level plane in the needle-out state); Figure 14 For the present invention Figure 13 Cross-section of parts a1 to a8; Figure 15 For the present invention Figure 13 A cross-sectional view of the portion a9 to a12 in FIG; Figure 16 For the present invention Figure 13 Magnified view of region F in ; Figure: 1. Guidewire quick-exchange section; 1a. Curved connector; 2. Introducer needle sheath; 3. Catheter body; 4. Introducer needle pusher; 4a. Catheter body; 5. Anti-slip push button; 6. Push slider; 7. Delivery tube; 8. Delivery tube outlet; 9. Guidewire exchange channel outlet; 10. Guidewire exchange channel inlet; 11. Introducer needle outlet; 12. Guidewire exchange channel; 13. Front metal marker ring; 14. Middle metal marker ring; 15. Rear metal marker ring; 16. Upper guide rail; 17. Lower guide rail; 18. Left stop slot; 19. Right stop slot; 20. Introducer needle; 21. Introducer needle-delivery tube connection; 22. Intraluminal lumen of delivery tube; 23. Left guide key; 24. Right guide key; 25. Delivery tube-push slider connection; 26. Middle connection; 27. Tail end interface; 28. Microguidewire; 29. Side perfusion tube base; 30. Side perfusion tube; 31. External opening of the side perfusion tube; 32. Side perfusion tube channel; 33. Guide cone; 34. Guide cone peephole. DETAILED DESCRIPTION

[0053] To make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0054] refer to Figures 5 to 16 A flexible intravascular targeted delivery catheter comprises a guidewire quick exchange section 1, a puncture needle sheath 2, and a catheter body 3 connected in sequence; the guidewire quick exchange section 1 is located at the front end of the puncture needle sheath 2, and a guidewire exchange channel 12 for the passage of a micro guidewire 28 is axially arranged in the guidewire quick exchange section 1, the inlet 10 of the guidewire exchange channel is arranged on the side wall of one end of the guidewire quick exchange section 1 close to the puncture needle sheath 2, and the outlet 9 of the guidewire exchange channel is arranged at the front end of the guidewire quick exchange section 1; a delivery tube 7 is arranged in the catheter body 3, and the front end of the delivery tube 7 is connected to There are three puncture needles 20 evenly distributed along the circumferential direction and located in the puncture needle sheath 2; the front side wall of the puncture needle sheath 2 is evenly distributed along the circumferential direction with three puncture needle outlets 11; the rear side wall of the catheter body 3 is connected to the side perfusion tube 30, and the rear end of the catheter body 3 is connected to the puncture needle pushing device 4. The puncture needle pushing device 4 drives the puncture needle 20 by driving the delivery tube 7 to push it forward to pass through the puncture needle outlet 11 and retreat into the puncture needle sheath 2. The rear end of the delivery tube 7 passes through the rear end of the puncture needle pushing device 4 and is provided with a tail end interface 27.

[0055] In this embodiment, the rear portion of the guidewire rapid exchange section 1 has an arcuate connection portion 1a that connects to the puncture needle sheath 2, so that the axis of the guidewire exchange channel 12 is not coaxial with the axis of the catheter body 3. Specifically, the axis of the guidewire exchange channel 12 is parallel to the axis of the catheter body 3 and is located below the axis of the catheter body 3. The fact that the guidewire exchange channel 12 is not parallel to the catheter body 3 effectively reduces the diameter of the catheter body 3, facilitating access to smaller diameter vessels and deeper tissues while also reducing manufacturing complexity.

[0056] In this embodiment, the front outer wall of the guidewire rapid exchange section 1 is wrapped with a front metal marking ring 13 that is not radiopaque to facilitate marking and positioning during surgery.

[0057] In this embodiment, the outer diameter of the guidewire rapid exchange segment 1 is 0.7-0.9 mm and the length is 9-11 mm; the diameter of the guidewire exchange channel is 0.45-0.55 mm. Specifically, the outer diameter of the guidewire rapid exchange segment 1 can be 0.8 mm and the length can be 10 mm.

[0058] In this embodiment, the microguidewire 28 is a 0.018-inch microguidewire. The diameter of the guidewire exchange channel 12 is 0.5 mm. The 0.018-inch microguidewire 28 can be used to introduce instruments into the blood vessel, precisely guiding the catheter to the target area. During treatment, the microguidewire 28 can remain in place. If complications such as vascular spasm, dissection, and obstruction occur, requiring adjunctive treatment with other interventional devices, the small caliber of the microguidewire 28 allows for a good match with most treatment devices, facilitating rapid exchange and effectively resolving complications that may arise during treatment.

[0059] In this embodiment, three puncture needle outlets 11 are evenly distributed on the front side wall of the puncture needle sheath 2, spaced 120 degrees apart. This ensures that after reaching the target area, the three micropuncture needles 20 are pushed forward by the rear puncture needle pushing device 4, deployed forward and outward from the puncture needle sheath 2, and penetrate or pierce the blood vessel wall. The drug is injected into the delivery tube 7 through the delivery tube outer port 8 on the tail end interface 27, thereby achieving the purpose of localized targeted treatment. When the needle is retracted and in the retracted state, the puncture needles 20 are enclosed in the puncture needle sheath 2 and enter and exit the blood vessel through the head end guidewire quick exchange section 1, preventing the puncture needles 20 from protruding from the catheter and damaging the blood vessel wall.

[0060] In this embodiment, the diameter of the puncture needle sheath 2 is 1-1.5 mm, and the length is 14-16 mm; specifically, the length of the puncture needle sheath 2 can be 15 mm.

[0061] In this embodiment, the puncture needle 20 is a hollow needle prefabricated from medical steel 440 and shaped in an outwardly curved shape. After extending from the puncture needle outlet 11, it can be extended forward and outward to penetrate the blood vessel wall. This material is harder and sharper than conventional nickel-titanium alloy, making it easier to penetrate plaques such as atherosclerotic plaques and tough fibrous connective tissue.

[0062] In this embodiment, three puncture needles 20 are connected to the delivery tube 7 through the puncture needle-delivery tube connection part 21 in the cavity of the catheter body 3. The liquid substance injected through the delivery tube outer port 8 on the tail end interface 27 can be delivered to the target site through the three puncture needles 20.

[0063] In this embodiment, a guide cone 33 is provided in the puncture needle sheath 2 and at the rear end position near the puncture needle outlet 20. Three guide cone peep holes 34 are axially provided on the guide cone 33, which are evenly distributed at intervals of 120° in the circumferential direction and are used to allow three puncture needles 20 to pass through. The guide cone peep holes 34 are slightly inclined outward from the back to the front.

[0064] Three guide cone holes 34 extending forward and outward allow the three micropuncture needles 20 to be precisely guided to the puncture needle outlet 11 and then ejected. This device offers two key advantages: First, the guide cone 33 design fully utilizes the forward thrust, enabling the puncture needles 20 to effectively penetrate the blood vessel wall. Second, the device's design enables the use of standard medical steel to manufacture sufficiently tough puncture needles 20, eliminating the need for preformed nickel-titanium alloy (which is softer and less sharp), significantly improving puncture efficiency.

[0065] In this embodiment, the front and rear end outer walls of the puncture needle sheath 2 are correspondingly wrapped with a middle metal marking ring 14 and a rear metal marking ring 15 that are not X-ray transparent, so as to distinguish them from the front guide wire quick exchange section 1 and the rear catheter body 3, so as to facilitate positioning and calibration during surgery.

[0066] In this embodiment, an irrigation tube base 29 is fixed to the rear left side wall of the catheter body 3 near the puncture needle pushing device 4 , and the side irrigation tube 30 is connected to the catheter body 3 via the irrigation tube base 29 .

[0067] In practical applications, the design of the side perfusion tube 30 has multiple clinical application values. On the one hand, it can be used to inject normal saline through the outer port 31 of the side perfusion tube before surgery to empty the air in the catheter, thereby ensuring the safe use of the device. On the other hand, during surgery, contrast agent can be injected through the outer port 31 of the side perfusion tube to perform real-time angiography of the target blood vessels, so as to accurately assess the real-time condition of the blood vessels, including whether there is dissection, rupture, spasm or obstruction. Based on the angiography results, appropriate treatment measures can be taken in a timely manner. For example, in the event of vascular spasm, antispasmodic drugs can be directly injected through the side perfusion tube to achieve a rapid and efficient response to complications.

[0068] In this embodiment, the length of the catheter body 3 is 1000-1200 mm, the diameter is 1-1.5 mm, and the catheter body 3 and the puncture needle sheath 2 have the same caliber.

[0069] In this embodiment, the puncture needle pushing device 4 includes a tubular body 4a connected to the rear end of the catheter body 3. A push slider 6 is slidably connected to the tubular body 4a. A non-slip push button 5 is provided on the top of the push slider 6. The upper surface of the non-slip push button 5 is engraved with horizontal grooves to enhance friction during operation and facilitate forward and backward movement. The push slider 6 has an intermediate connecting portion 26 that penetrates the tubular body 4a and is fixed to the outer wall of the delivery tube 7. The intermediate connecting portion 26 is made of a polymer material and is tightly connected to the delivery tube 7. A matching sliding limit structure is provided between the push slider 6 and the outer wall of the tubular body 4a. The movement of the push slider 6 performs the pushing and retracting operations of the puncture needle 20.

[0070] In this embodiment, the sliding limit structure includes a left limit groove 18 and a right limit groove 19 provided on the left and right side walls of the tube body 4a and partially penetrated. A left guide key 23 and a right guide key 24 are provided on the left and right inner walls of the push slider 6, respectively. The left guide key 23 and the right guide key 24 respectively engage with the corresponding left limit groove 18 and right limit groove 19 by mortise and tenon. The sliding limit structure with mortise and tenon cooperation can achieve sliding limit of the push slider 6 and facilitate stable pushing and retracting operations.

[0071] In this embodiment, an upper guide rail groove 16 and a lower guide rail groove 17 are correspondingly provided at the top and bottom of the tube body 4 a , and the intermediate connecting portion 26 passes through the upper guide rail groove 16 and the lower guide rail groove 17 to be fixedly connected to the conveying pipe 7 .

[0072] In this embodiment, the upper and lower guide rail grooves 16 and 17 cooperate with the left and right limit grooves 18 and 19 to effectively ensure the stability and smoothness of the pushing process. During the pushing operation, the guide rail grooves provide a precise guide path for the pushing action, while the limit grooves effectively limit the puncture needle 20 after it is pushed to the set position, preventing it from sliding backward due to external force or improper operation, thereby ensuring the accuracy and reliability of the entire pushing process.

[0073] In this embodiment, the inner center of the intermediate connecting portion 26 is tightly connected to the delivery tube 7 via the polymer delivery tube-pushing slider connecting portion 25. The intermediate connecting portion 26 slides back and forth along the upper guide groove 16 and the lower guide groove 17 of the pushing device 4 to push the puncture needle 20 through the puncture needle outlet 11 of the puncture needle sheath 3 to expand and retract.

[0074] In this embodiment, the surfaces of the left and right limit slots 18, 19, upper guide slots 16, and lower guide slots 17 are all provided with scales in millimeters, enabling precise control of the depth and length of the insertion and withdrawal of the puncture needle 20. With these quantitatively guided scales, the operator can precisely adjust the insertion depth and withdrawal distance of the puncture needle 20 according to specific needs during the procedure, thereby ensuring the accuracy and safety of the surgical procedure and avoiding potential complications caused by improper puncture depth.

[0075] In this embodiment, the diameter of the tube 4a of the puncture needle pushing device 4 is 4-6 mm, and the length is 22-28 mm. Specifically, the diameter of the tube 4a of the puncture needle pushing device 4 is 5 mm, and the length is 25 mm.

[0076] In this embodiment, the length of the pushing slider 6 can be 10 mm and the width can be 5 mm.

[0077] In this embodiment, the delivery tube 7 passes through the catheter body 3, and when the puncture needle 20 is fully deployed, its tail end interface 27 is still exposed at the rear of the puncture needle pushing device 4. The delivery tube 7 is made of medical steel 440 and has an outer diameter of 0.5 mm.

[0078] In this embodiment, the tail end interface 27 is coated with a polymer material layer, which facilitates the connection of peripheral devices such as syringes.

[0079] The single-channel delivery tube 7 design differs from traditional micropuncture catheters with multiple (usually three) needles. In traditional designs, each needle is equipped with a separate delivery tube. While this structure enables independent operation of multiple needles, it inevitably increases the overall stiffness of the catheter, significantly reducing its flexibility and limiting its rotational maneuverability when navigating tortuous blood vessels. Furthermore, the higher catheter stiffness can easily damage the vessel wall during delivery, leading to serious complications such as dissection and rupture.

[0080] In contrast, the present invention utilizes a single-channel delivery tube 7, with the front end connected to three puncture needles 20, effectively reducing the overall stiffness of the catheter and further reducing its outer diameter. This design not only optimizes the catheter's mechanical properties, making it easier to rotate and manipulate, but also significantly enhances its ability to navigate small vascular branches, thereby expanding the application range of endovascular treatment.

[0081] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, designing different forms of flexible intravascular targeted delivery catheters does not require creative labor. All equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention without departing from the principles and spirit of the present invention should be covered by the scope of the present invention.

Claims

1. A flexible intravascular targeted delivery catheter, characterized in that: It includes a guidewire quick exchange section, a puncture needle sheath, and a catheter body that are connected in sequence; the guidewire quick exchange section is located at the front end of the puncture needle sheath, and a guidewire exchange channel for a microguidewire is axially arranged in the guidewire quick exchange section, and the entrance of the guidewire exchange channel is arranged on the side wall of one end of the guidewire quick exchange section close to the puncture needle sheath; a delivery tube is arranged in the catheter body, and the front end of the delivery tube is connected to three puncture needles that are evenly distributed in the circumferential direction and located in the puncture needle sheath; the front side wall of the puncture needle sheath is evenly distributed in the circumferential direction. Three puncture needle outlets are evenly distributed; the rear side wall of the catheter body is connected to a side perfusion tube, and the rear end of the catheter body is connected to a puncture needle pushing device that drives the delivery tube to push and retract the puncture needle, and the rear end of the delivery tube passes through the rear end of the puncture needle pushing device and is provided with a tail end interface.

2. The flexible intravascular targeted delivery catheter according to claim 1, characterized in that: The rear portion of the guidewire quick exchange section has an arc-shaped connecting portion connected to the puncture needle sheath so that the axis of the guidewire exchange channel and the axis of the catheter body are not on the same axis.

3. The flexible intravascular targeted delivery catheter according to claim 1, characterized in that: The three puncture needle outlets are evenly distributed on the front side wall of the puncture needle sheath at an interval of 120 degrees. The puncture needles are in an outward arc shape. The three puncture needles are connected to the delivery tube through the puncture needle-delivery tube connection part in the catheter body cavity.

4. The flexible intravascular targeted delivery catheter according to claim 1 or 3, characterized in that: A guide cone is provided in the puncture needle sheath and at the rear end position near the puncture needle outlet. The guide cone is axially provided with three guide cone peep holes evenly distributed along the circumferential direction and used for the puncture needle to pass through. The guide cone peep holes are inclined outward from the back to the front.

5. The flexible intravascular targeted delivery catheter according to claim 1, characterized in that: The puncture needle pushing device includes a tube body connected to the rear end of the catheter body, a pushing slider is slidably connected to the tube body, and the pushing slider has an intermediate connecting portion that penetrates the tube body and is fixed to the outer wall of the delivery tube. A matching sliding limiting structure is provided between the pushing slider and the outer wall of the tube body.

6. The flexible intravascular targeted delivery catheter according to claim 5, characterized in that: The sliding limiting structure includes a left limiting groove and a right limiting groove arranged on the left and right side walls of the tube body, and the left and right inner walls of the pushing slider are correspondingly provided with guide keys that cooperate with the mortise and tenon of the left limiting groove and the right limiting groove.

7. The flexible intravascular targeted delivery catheter according to claim 6, characterized in that: The top and bottom of the tube body are respectively provided with an upper guide rail groove and a lower guide rail groove, and the middle connecting part passes through the upper guide rail groove and the lower guide rail groove and is fixedly connected to the conveying pipe; the surfaces of the limit groove and the guide rail groove are both provided with a scale in mm.

8. The flexible intravascular targeted delivery catheter according to claim 5, 6 or 7, characterized in that: The middle connecting part is made of polymer material and is tightly connected to the delivery pipe; the top of the pushing slider is provided with an anti-slip pushing button.

9. The flexible intravascular targeted delivery catheter according to claim 1, 2, 3, 5, 6 or 7, characterized in that: The front outer wall of the guide wire quick exchange section is wrapped with a front metal marker ring that is not X-ray transparent, and the front and rear outer walls of the puncture needle sheath are correspondingly wrapped with a middle metal marker ring and a rear metal marker ring that are not X-ray transparent.

10. The flexible intravascular targeted delivery catheter according to claim 1, 2, 4, 5, 6 or 7, characterized in that: The delivery tube and puncture needle are both made of medical steel 440, and the tail end interface is coated with a polymer material layer; the rear side wall of the catheter body is fixed with an infusion tube base, and the side infusion tube is connected to the catheter body through the infusion tube base.

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