CN102058927A - Hardness-controlled intelligent conduit for clinical intervention treatment - Google Patents

Abstract

The invention discloses an intelligent catheter with adjustable hardness for clinical interventional treatment. The catheter includes an outer catheter (1) and an inner tube (3). The main structure can adopt the existing catheter structure. There is a metal reinforcement layer (2); a structure containing a temperature-sensitive polymer layer can also be adopted, and a metal resistance layer (5) is provided on the outer wall (3) of the inner tube. A temperature-sensitive polymer layer (4) is coated on the outer catheter (1). Applying a voltage or current signal to the metal reinforcement layer (2) or the metal resistance layer (5) generates a local thermal effect, increases the temperature of the temperature-sensitive polymer layer, and reduces its Young's modulus (that is, hardness). When the electrical signal is cut off, the temperature of the polymer layer will continue to decrease, while the hardness of the catheter will gradually increase until it reaches the initial hardness. This intelligent catheter with adjustable hardness can greatly reduce the cost of frequent catheter replacement, reduce the difficulty and risk of surgery, and shorten the operation time.

Description

An intelligent catheter with adjustable hardness for clinical interventional therapy

technical field

The invention relates to an intelligent catheter, in particular to an intelligent catheter with adjustable hardness for clinical interventional treatment.

technical background

Intervention therapy is a minimally invasive treatment method developed internationally in recent years using modern high-tech means. Under the guidance of medical imaging equipment (digital X-ray machine, CT machine, nuclear magnetic resonance machine), it introduces special catheters, guide wires and other precision instruments into the patient's body to diagnose and locally treat the lesion in the body. Compared with traditional medical drug treatment and surgical treatment, interventional treatment has the characteristics of no surgery, less trauma, quicker recovery, and better effect. With the improvement of its technology, interventional therapy can now reach almost all vascular branches and other luminal structures (digestive tract, biliary tract, trachea, nasal tube, etc.) The most important treatment methods for liver cancer, lung cancer, aneurysm, acute coronary heart disease, uterine fibroids, etc., together with internal medicine and surgery, are called the three major clinical diagnosis and treatment techniques.

Catheter is the main instrument of interventional therapy and plays a pivotal role in interventional therapy. Choosing the right catheter is one of the prerequisites and key technologies for successful interventional surgery. According to the application, catheters can be divided into guiding catheters, contrast catheters, drug delivery catheters, rotational atherectomy catheters and dilatation catheters, etc. Catheters with different functions generally have different hardness (or different rigidity or flexibility). Even if a catheter with a specific function is used, doctors often need to replace the catheter several times during the operation to ensure the smooth progress of the operation according to the different parts of the body involved and the differences between individual patients. Taking the guiding catheter used in interventional treatment of coronary heart disease as an example, the catheter first enters the human body from the femoral artery or radial artery, and is sent along the artery to the coronary artery lesion for fixation. This procedure requires the guiding catheter to have good flexibility so that it can travel along the tortuous blood vessel without damaging the vessel wall of the approach. After the position of the catheter is fixed, when the stent with the balloon is inserted from its internal cavity, the guide catheter is usually required to have relatively high hardness to resist the pressure applied to the catheter during the advancement of the stent. However, none of the developed catheters currently on the market can simultaneously meet these requirements. In order to solve this problem, the current clinical compromise method is to prepare a series of catheters with different hardness, first insert the catheter with low hardness, and then replace it with a catheter with higher hardness until the hardness of the catheter reaches the target requirement. Although this method solves the contradiction between the catheter hardness mismatch requirements during the introduction of the catheter and the stent, it also causes new problems: first, it greatly prolongs the time of interventional therapy. According to statistics, the time from the initial insertion of the soft catheter to the final fixation of the catheter with ideal hardness accounts for one-third of the total time of the entire interventional treatment. Since the introduction and fixation of the catheter requires the auxiliary positioning of radiological medical imaging equipment, prolonging the process means increasing the time for patients to be exposed to radioactive rays; second, replacing the catheter multiple times increases the cost of treatment and increases the possibility of puncturing the vessel wall Sex, thus increasing the risk and difficulty of surgery.

With the continuous improvement of other related equipment and technologies in interventional therapy, the contradiction that the hardness of a single catheter cannot be adjusted is particularly prominent nowadays. How to solve this problem comprehensively and effectively has become an inevitable requirement for further improvement of interventional therapy technology. Unfortunately, due to the lack of clear ideas, its research is still in its infancy worldwide. Most of the work is mainly focused on the mechanical modification of the internal structure of the catheter, such as dividing the existing single-layer composite catheter wall into two or more independent layers, each layer of material has different hardness, and the gap between the layers is used to Adjust its overall hardness. However, even with such a complex catheter structure, the adjustable range of catheter stiffness is still limited, which cannot meet the actual clinical needs.

Contents of the invention

The technical problem to be solved by the present invention is to provide an intelligent catheter with adjustable hardness for clinical interventional therapy, to replace the single hardness catheter used in existing clinical interventional therapy, and effectively solve the problem of frequent replacement of catheters in interventional operations to adapt to different hardness demanding puzzle.

The present invention is realized through the following technical solutions:

An intelligent catheter with adjustable hardness for clinical interventional treatment, the catheter includes an outer catheter and an inner tube, and is characterized in that the outer catheter is coated with a temperature-sensitive high molecular polymer layer.

In the aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the temperature-sensitive polymer layer is co-extruded with the outer tube and the inner tube.

The above-mentioned intelligent catheter with adjustable hardness for clinical interventional treatment, the outer catheter material is block polyurethane, nylon, polyethylene or polyvinyl chloride, and the inner tube material is polytetrafluoroethylene or block polyurethane; The outer wall of the inner tube has a metal reinforcement layer or a metal resistance layer.

In the aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the temperature-sensitive polymer layer is coated on the outer wall of the outer catheter.

In the aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the temperature-sensitive high molecular polymer has biocompatibility, and the glass transition temperature or melting point is close to the normal temperature range of the human body.

In the aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the temperature-sensitive polymer layer is one or more of paraffin, polycaprolactone, polyurethane, and polyvinyl acetate.

The aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the temperature-sensitive polymer layer is a composite of one or more of paraffin, polycaprolactone, polyurethane, polyvinyl acetate and inorganic nanoparticles. thing.

In the aforementioned intelligent catheter with adjustable hardness for clinical interventional therapy, the metal resistance layer is plated on the outer wall of the inner tube by means of electroplating, electroless plating or magnetron sputtering.

The material of the outer tube layer is generally block polyurethane, nylon, polyethylene and polyvinyl chloride; the material of the inner tube layer is generally polytetrafluoroethylene or block polyurethane.

Compared with the single hardness catheter commonly used at present, the present invention has the following advantages:

(1) An intelligent catheter with adjustable hardness for clinical interventional therapy according to the present invention can reversibly change the hardness of the distal end of the catheter or any part within a narrow temperature range that the human body can tolerate, completely solving the problems often encountered in interventional therapy Conduit stiffness mismatch problem.

(2) The shape memory function of the intelligent catheter with adjustable hardness for clinical interventional therapy according to the present invention is helpful for the fixation of the catheter in the body after the disappearance of the stimulating electrical signal, and avoids complications caused by subsequent surgical operations. The phenomenon that the catheter is detached from the lesion greatly reduces the difficulty and risk of the operation and shortens the operation time.

(3) Compared with the production process of the existing catheter, the present invention only needs to make appropriate changes in the process flow, and the outer layer of the inner catheter is coated with a temperature-sensitive polymer layer to be used for the production of smart catheters, and the capital investment is low. Large, but the effect is extremely obvious, and has broad prospects for industrial application.

Description of drawings

FIG. 1 is a schematic diagram of a main structure of a smart catheter with adjustable hardness.

Fig. 2 is a schematic diagram of another main structure of the smart catheter with adjustable hardness.

Fig. 3 is a graph showing the performance test results of the smart catheter with adjustable hardness in the embodiment.

Detailed ways

The present invention will be further described below by taking paraffin as an example in conjunction with the accompanying drawings and embodiments, but is not limited thereto.

The main structure of the intelligent catheter can adopt the existing catheter structure, which is to coat a layer of temperature-sensitive polymer layer 4 on the outer wall of the outer catheter 1 of the existing catheter structure, and have a metal reinforcement layer 2 on the outer wall of the inner tube; The polymer layer structure has a metal resistance layer 5 on the outer wall of the inner tube. By applying a voltage or current signal to the metal reinforcement layer 2 or the metal resistance layer 5 on the outer wall of the existing catheter inner tube, a local thermal effect is generated, the temperature of the temperature-sensitive polymer layer is increased, and the Young's modulus (that is, the hardness) is reduced. ). If the electrical signal is cut off at this time, the temperature of the polymer layer will continue to decrease, while the hardness of the catheter can gradually increase until it reaches the initial hardness. The metal resistance layer can be plated on the outer wall of the inner tube by means of electroplating, chemical plating or magnetron sputtering, and the temperature-sensitive polymer layer can be spin-coated on the outer tube or extruded together with the outer tube and the inner tube. Under the premise that the resistance of the metal reinforcement layer or the metal resistance layer is constant, each hardness value in the hardness variation range corresponds to a specific voltage value or current value. In other words, the hardness of the smart catheter can be adjusted by adjusting the voltage or current. Precise control. If the thickness of the temperature-sensitive polymer layer is constant, the voltage or current required to achieve the same hardness can be changed by the resistance of the metal reinforcement layer or the additional metal resistance layer.

The temperature-sensitive high molecular polymer layer can not only be located at the distal end of the smart catheter, but also can be distributed on the entire catheter or any part thereof. The distal end of the smart catheter adopts a 4-layer structure containing a temperature-sensitive high molecular polymer. Its mechanism of action can be illustrated by examples, such as modifying the distal end of the guide catheter with a temperature-sensitive polymer layer, and applying an electrical signal during the introduction of the guide catheter into the human blood vessel can rapidly reduce the hardness of the tip of the guide catheter, which is beneficial to the catheter along the Walk along the winding and branched blood vessels without stabbing the passing blood vessel wall. After reaching the lesion site, the electrical signal is withdrawn, and the hardness of the catheter can be restored again. At this time, the shape of the catheter tip can be compared with the shape of the surrounding blood vessels. Keep consistent, that is, it has a certain shape memory function, so that it will not deviate from the established position during subsequent operations (replacement of guide wire, injection of drugs, or insertion of stents, etc.), which greatly reduces the difficulty and risk of surgery and shortens the operation time. time.

Example 1

Laboratory Preparation of Smart Catheters

A commercially available 32 μm thick polyimide tube (inner diameter of 1.14mm, 0.045") was fixed on a thin metal round rod with the same inner diameter, and the outer surface of the polyimide tube was coated by electroless plating. After the surface is uniformly plated with about 25nm thick copper (resistance is 30Ω), the paraffin is dissolved in the organic solvent chloroform and then spin-coated on the outer surface of the polyimide tube coated with a metal layer. The thickness of the paraffin layer depends on the concentration of the paraffin organic solution. and spin-coating speed adjustment, spin-coat paraffin layers with a thickness of 124, 213, 314, and 425 μm in turn according to this method. After the solvent is completely evaporated, nest it into a polyimide tube with a larger inner diameter to obtain a smart catheter , the hardness test was carried out on the Electroforce Electromagnetic Dynamic Static Mechanical Testing Machine (Bose Company), and the results are shown in Figure 2.

During the process of the current signal changing from 0 to 200mA, the hardness of the four groups of smart catheters with different thicknesses varied from 2.3-0.6GPa (124μm), 1.72-0.48GPa (213μm), 1.25-0.25GPa (314μm), 1.16 -0.17GPa (425μm).

Under the same experimental conditions, the hardness variation range of the existing commercial guide catheter (2F-8F) is 1.24-1.09GPa. It can be seen that the intelligent catheter with adjustable hardness of the present invention has a wider adjustable range of hardness than the existing guiding catheter, and is obviously superior in performance to the existing guiding catheter.

Example 2

Industrial Production of Smart Catheters

Appropriate modifications are made to the existing catheter process, that is, the outer tube, temperature-sensitive high molecular polymer and inner tube are co-extruded by composite extrusion, and the tube wall can be reinforced with metal wire or mesh. If an additional metal resistance layer is required, a thin layer of metal can be plated on the outer surface of the inner tube layer by electroless plating, and the time of electroless plating can be controlled to adjust the resistance.

Claims (9)

1. adjustable hardness intelligent duct that is used for clinical interventional therapy, described conduit comprises outer catheter (1) and interior pipe (3), it is characterized in that being coated with on the outer catheter (1) responsive to temperature high polymer layer (4).

2. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1, it is characterized in that described outer catheter (1) material is block polyurethane, nylon, polyethylene or polrvinyl chloride, interior pipe (3) material is politef or block polyurethane; Pipe (3) outer wall has metal enhancement layer (2) or metallic resistance layer (5) in described.

3. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that described responsive to temperature high polymer layer (4) is coated in the outer wall of outer catheter (1).

4. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that (4) employing of described responsive to temperature high molecular polymerization layer and outer tube, the compound extrusion way of interior pipe.

5. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that described responsive to temperature high molecular polymer (4) has biocompatibility, and glass transition temperature or fusing point are near blood heat's scope.

6. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that described responsive to temperature high molecular polymerization layer (4) is one or more of paraffin, polycaprolactone, polyurethane, polyvinyl acetate.

7. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that the complex of described responsive to temperature high molecular polymerization layer (4) for one or more and inorganic nano-particle of paraffin, polycaprolactone, polyurethane, polyvinyl acetate.

8. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that described metallic resistance layer (5) adopts plating, chemical plating or magnetron sputtering mode to be plated on the outer wall of inner tube.

9. a kind of adjustable hardness intelligent duct that is used for clinical interventional therapy according to claim 1 is characterized in that described agent structure can adopt existing guide-tube structure, and metal enhancement layer (2) is arranged on the outer wall of inner tube (3); Also can adopt to contain responsive to temperature high polymer layer structure, metallic resistance layer (5) is arranged on the outer wall of inner tube (3).

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