CN114533129A - Intravascular ultrasound catheter with spring structure - Google Patents

Abstract

The present disclosure provides an intravascular ultrasound catheter with a spring structure, comprising: the sheath pipe, it has the buffer layer and covers the skin of buffer layer, the sheath pipe has the guide inner chamber to and the transmission shaft, the transmission shaft has spring structure and the cladding of coating at spring structure, spring structure is formed by two-layer spring of interior spring structure and outer spring structure, and outer spring structure passes through the adhesive and fixes at the structural including spring, and the transmission shaft is in contact with the buffer layer of sheath pipe, and wherein, the transmission shaft forms sliding friction with the sheath pipe via the buffer layer. In the present disclosure, the sheath has a guide lumen, the transmission shaft is movable along the guide lumen of the sheath, and the transmission shaft forms sliding friction with the sheath via the buffer layer, in which case the transmission shaft can reduce friction with the sheath when rotating and retracting at high speed, so that it can be ensured that the ultrasonic transducer connected with the transmission shaft can collect a clear ultrasonic image in the retracting process.

Description

Intravascular ultrasound catheter with spring structure

The application date of the application is 27.12.2018, the application number is 201811616024.4, and the invention is a divisional application of a patent application named as an intravascular ultrasound catheter.

Technical Field

The present disclosure relates to the field of interventional medical technology, and more particularly, to an intravascular ultrasound catheter with a spring structure.

Background

Intravascular Ultrasound (IVUS) refers to systems that use Ultrasound and interventional catheter techniques for Intravascular Ultrasound imaging. The technology is mainly characterized in that a miniaturized ultrasonic transducer is placed at a specific position in a blood vessel through an interventional catheter, when the ultrasonic transducer is withdrawn, the ultrasonic transducer generates ultrasonic signals, the ultrasonic signals are transmitted and reflected in human tissues, the received reflected signals are converted into electric signals, and then an image processing unit of an IVUS host system processes and displays the electric signals, so that image information of the lumen and the wall of the blood vessel is obtained.

The mechanical IVUS system ultrasound catheter currently on the market generally has two parts, a sheath and a drive shaft, the inside of the sheath allows the movement of the drive shaft with the ultrasound transducer. During IVUS imaging, the drive shaft is rotated and retracted at high speed, the outer sheath is kept stationary, and ultrasound imaging information is obtained at the target site (e.g., stenosis of a blood vessel) by rotating the ultrasound transducer. In the existing ultrasonic catheter, although a certain gap is left between the transmission shaft and the sheath, when the distal end sheath enters a tortuous coronary vessel, the friction force between the transmission shaft and the sheath is increased, which easily causes the imaging of the ultrasonic transducer to generate uneven rotation artifacts, thereby affecting the judgment of medical staff.

Disclosure of Invention

In view of the above-described conventional circumstances, an object of the present invention is to provide an intravascular ultrasound catheter capable of improving the imaging clarity of a drive shaft during imaging.

In order to solve the above technical problems in the prior art, the present invention provides an intravascular ultrasound catheter, comprising: a sheath having a buffer layer and an outer layer covering the buffer layer, the sheath having a guide lumen, and the sheath being flexible; and a transmission shaft having an ultrasonic transducer and movable along the guide lumen of the sheath, the transmission shaft having flexibility, wherein the transmission shaft forms sliding friction with the sheath via a buffer layer.

In the intravascular ultrasound catheter, the sheath is provided with the guide inner cavity, the transmission shaft can move along the guide inner cavity of the sheath, and the transmission shaft and the sheath form sliding friction through the buffer layer.

In the intravascular ultrasound catheter according to the present invention, the buffer layer is optionally formed of at least one selected from the group consisting of polytetrafluoroethylene, molybdenum disulfide, polyvinyl chloride, and polyester elastomer. Thereby, the sliding friction between the cushion layer and the propeller shaft can be further improved.

In the intravascular ultrasound catheter according to the present invention, the sheath may have a proximal end portion and a distal end portion connected to the proximal end portion, and the sheath may have an outer diameter gradually decreasing from the proximal end portion to the distal end portion. This can reduce the resistance to the intravascular ultrasound catheter from traveling through the blood vessel.

In the intravascular ultrasound catheter according to the present invention, the outer layer may have a young's modulus greater than that of the buffer layer. This can achieve both flexibility of the inner layer and hardness of the outer layer of the sheath tube.

In the intravascular ultrasound catheter according to the present invention, the drive shaft optionally has a spring structure and a coating applied to the spring structure. In this case, the good flexibility of the transmission shaft can be ensured, and the contact friction between the transmission shaft and the sheath can be improved.

In the intravascular ultrasound catheter according to the present invention, the spring structure is optionally formed of at least one selected from the group consisting of metal, alloy, carbon, rubber, and resin. Thereby, the spring can be improved in the ability to resist twisting.

In the intravascular ultrasound catheter according to the present invention, the outer layer is optionally coated with a lubricious coating on the surface thereof. This improves the resistance to the intravascular ultrasound catheter traveling through the blood vessel.

In the intravascular ultrasound catheter according to the present invention, the coating layer is optionally formed of at least one selected from the group consisting of polyvinylpyrrolidone, polyoxyethylene, polyphenylene oxide, and maleic acid. This can improve the biocompatibility of the coating.

In the intravascular ultrasound catheter according to the present invention, the buffer layer and the outer layer may be bonded by thermal fusion welding, the thermal fusion welding being at least one of resistance heating welding, infrared heating welding, laser thermal fusion welding, and ultrasonic welding. This enables the buffer layer to be welded favorably to the outer layer of the sheath tube.

According to the present disclosure, an intravascular ultrasound catheter is provided that can improve the imaging clarity of a drive shaft during imaging.

Drawings

Fig. 1 is a schematic diagram illustrating an intravascular ultrasound system including an intravascular ultrasound catheter in accordance with the present disclosure.

Fig. 2 is a schematic internal view showing an intravascular ultrasound catheter according to the present disclosure.

Fig. 3 is a schematic diagram showing an example of the outer shape of the sheath of the intravascular ultrasound catheter according to the present disclosure.

Fig. 4 is a schematic diagram illustrating a sheath and a coating of an intravascular ultrasound catheter according to the present disclosure.

Figure 5 is a schematic diagram illustrating a cross-section along line a-a' of figure 4 of an intravascular ultrasound catheter according to the present disclosure.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals, and redundant description thereof is omitted. The drawings are schematic and the ratio of the dimensions of the components and the shapes of the components may be different from the actual ones.

Fig. 1 is a schematic diagram illustrating an intravascular ultrasound system including an intravascular ultrasound catheter in accordance with the present disclosure.

As shown in fig. 1, an intravascular ultrasound system (IVUS) may include an intravascular ultrasound catheter (hereinafter sometimes simply referred to as "ultrasound catheter") 1, a retraction system 2 connected to the ultrasound catheter 1 and controlling retraction of the ultrasound catheter 1, and a host system 3 that processes imaging information acquired by the ultrasound catheter 1.

In some examples, when the intravascular ultrasound system is in operation, the ultrasound catheter 1 may be placed within a blood vessel inside the body, while the retraction system 2 and the host system 3 are outside the body, the retraction system 2 may control the movement of the ultrasound catheter 1 within the blood vessel and ultrasonically image a specific location within the blood vessel (e.g., a stenosis of the blood vessel), the ultrasound catheter 1 may communicate the obtained imaging information to the host system 3, and the host system 3 may process the imaging information to display an image of, for example, the lumen and inner wall within the blood vessel on the host system (e.g., a screen).

In some examples, the ultrasound catheter 1 may be removably mounted on the retraction system 2. In this case, the ultrasound catheter 1 may be installed or removed at the retraction system 2 as desired. In addition, in the present embodiment, the retraction system 2 may use different sizes and types of ultrasound catheters 1.

Fig. 2 is a schematic internal view showing an intravascular ultrasound catheter according to the present disclosure. Fig. 3 is a schematic diagram showing an example of the outer shape of the sheath of the intravascular ultrasound catheter according to the present disclosure.

In some examples, the ultrasound catheter 1 may include a sheath 11 and a drive shaft 12 (see fig. 2). The sheath 11 has a guide lumen 110, and the transmission shaft 12 is slidable along the guide lumen 110 of the sheath 11. Since the drive shaft 12 has an ultrasound transducer (not shown), the ultrasound transducer of the drive shaft 12 is capable of ultrasonically imaging the blood vessel as the drive shaft 12 slides along the guide lumen 110. In particular, an ultrasound signal is emitted by an ultrasound transducer, e.g. radially towards a blood vessel, where it propagates, for example, and the ultrasound transducer may receive echo signals reflected by tissue and convert the echo signals into electrical signals containing ultrasound imaging information.

In the above-described ultrasonic imaging process, the ultrasonic transducer is propagated to the blood vessel wall through, for example, an opening (not shown) of the drive shaft, and the sheath 11 is generally made of a material that is not sensitive to ultrasound, so that the blood vessel lumen and the surroundings can be ultrasonically imaged by, for example, retracting the ultrasonic transducer while rotating.

In the present embodiment, the sheath 11 may include a proximal end portion 11a and a distal end portion 11b (see fig. 3). In this embodiment, generally speaking, the distal portion 11b is closer relative to the proximal portion 11a, and the proximal portion 11a and the distal portion 11b are connected.

In some examples, the outer diameter of the sheath 11 may gradually decrease from the proximal end portion 11a to the distal end portion 11 b. In this case, the resistance that can reduce the travel of the sheath tube 11 in the blood vessel decreases. In addition, in some examples, the outer diameter of the distal end portion 11b of the sheath tube 11 may be formed in a shape gradually decreasing from the proximal end portion 11a to the distal end portion 11b by a thermoplastic, blow molding, heat melting, compression, or the like method.

In addition, although it is described above that the outer diameter of the sheath 11 may be gradually reduced from the proximal end portion 11a to the distal end portion 11b, the present embodiment is not limited thereto, and in some examples, the outer diameter of the sheath 11 may also be kept constant from the proximal end portion 11a to the distal end portion 11 b.

In addition, in the sheath 11 according to the present embodiment, the proximal end portion 11a and the distal end portion 11b may be formed of different materials. In addition, in some examples, the proximal end portion 11a and the distal end portion 11b may be formed by integral molding.

In addition, in some examples, the end of the distal end portion 11b of the sheath tube 11 may be in a circular arc shape (see fig. 3). This improves contact between the sheath 11 and an anatomical structure (for example, a blood vessel) in the patient, and reduces damage to the blood vessel by the sheath 11.

In addition, in some examples, the sheath 11 may have flexibility, thereby further mitigating damage to the blood vessel caused by the sheath 11 during movement. In some examples, distal portion 111 of sheath 11 may have a higher flexibility than proximal portion 112 of sheath 11.

As described above, the sheath tube 11 has the guide lumen 110 penetrating therethrough. In this case, the drive shaft 12 with the ultrasonic transducer may be moved (e.g., slid) along the guide lumen 110 of the sheath 11. In the case of performing ultrasonic imaging for example by an interventional operation on a human body using the ultrasonic catheter 1, the sheath 11 (for example, the distal end portion 11b of the sheath 11) is placed at a proper position of an anatomical structure of a patient (for example, a stenosed portion of a blood vessel), and in this case, the ultrasonic transducer of the drive shaft 12 can be retracted along the catheter lumen 110, and the stenosed portion of the blood vessel can be ultrasonically imaged by, for example, rotating the ultrasonic transducer while being retracted.

Fig. 4 is a schematic diagram illustrating an example of a catheter profile of an intravascular ultrasound catheter according to the present disclosure. Figure 5 is a schematic diagram illustrating a cross-section along line a-a' of figure 4 of an intravascular ultrasound catheter according to the present disclosure.

In some examples, sheath 11 may include a buffer layer 111 and an outer layer 112 covering buffer layer 111. In the sheath 11, the buffer layer 111 is disposed inside, so that the transmission shaft 12 contacts the buffer layer 111 in the guide lumen 110, that is, the transmission shaft 12 contacts the buffer layer 111 when the transmission shaft 12 moves in the guide lumen 110. In some examples, to reduce friction between the guide lumen 110 of the sheath 11 and the drive shaft 12, the drive shaft 12 forms sliding friction with the sheath 11 (specifically, the guide lumen 110) via the buffer layer 111.

In some examples, the thickness of outer layer 112 may be greater than the thickness of buffer layer 111. This can further enhance the supporting effect of the outer layer 112 on the cushion layer 111.

In some examples, buffer layer 111 of sheath 11 may be composed of a material having good lubricity. This improves friction between the transmission shaft 12 and the buffer layer 111 of the sheath 11 when the transmission shaft 12 is retracted. In some examples, buffer layer 111 may be formed of at least one selected from the group consisting of polytetrafluoroethylene, molybdenum disulfide, polyvinyl chloride, and polyester elastomer.

In some examples, outer layer 112 is disposed on buffer layer 111 and surrounds buffer layer 111. As described above, the outer layer 112 may cover the cushioning layer 111, and the outer layer may provide support for the cushioning layer 111. In other words, in the ultrasound catheter 1, the buffer layer 111 of the sheath 11 is located between the outer layer 112 of the sheath 11 and the transmission shaft 12.

In some examples, the outer layer 112 may be formed of at least one of ABS resin (acrylonitrile-butadiene-styrene copolymer), silicone rubber, polyphenylene sulfide, n-butanol, styrene butadiene rubber, molybdenum trioxide, nano graphene, and epoxy glue.

In some examples, the young's modulus of outer layer 112 may be greater than the young's modulus of buffer layer 111. For example, the outer layer 112 may be formed of silicon rubber having a relatively large young's modulus, and the buffer layer 111 may be formed of polyvinyl chloride having a relatively small young's modulus. In this case, the rigidity of the outer layer 112 may be higher than the rigidity of the cushion layer 111, so that the rigidity of the outer layer 112 can be better satisfied, and the friction between the cushion layer 111 and, for example, the propeller shaft 12 can be reduced.

In some examples, the buffer layer 111 and the outer layer 112 may be bonded by thermal welding. In some examples, the thermal welding may be at least one of resistance heating welding, infrared heating welding, laser thermal welding, and ultrasonic welding. In this case, the buffer layer 111 and the outer layer 112 can be firmly combined. In addition, in other examples, the buffer layer 111 and the outer layer 112 may be connected by gluing, adhering, or the like.

In some examples, the surface of the outer layer 112 may be coated with a coating (not shown). By applying the biocompatible coating 114, biocompatibility of the sheath 11 with, for example, blood vessels can be improved. In addition, in some examples, coating 114 may have good lubricity and hydrophilicity, enabling further reduction in friction between sheath 11 and, for example, the blood vessel, reducing resistance to travel of sheath 11 within the blood vessel, and inhibiting damage to the blood vessel by sheath 11.

In some examples, the coating 114 may be formed of at least one selected from polyvinylpyrrolidone, polyoxyethylene, polyphenylene oxide, and maleic acid. In some examples, the coating 114 may be bonded to the outer layer 112 by adhesion, heat staking, gluing, or the like.

In some examples, sheath 11 may have through holes (not shown) that allow blood flow to pass through. In this case, the sheath 11 can be moved more favorably within the blood vessel, and the influence of the sheath 11 on the blood flow condition in the blood vessel can be reduced.

In some examples, the ultrasound catheter 1 may include a drive shaft 12. The driving shaft 12 can be connected with an ultrasonic transducer, the retracting system 2 retracts the ultrasonic transducer by controlling the driving shaft 12, the ultrasonic transducer needs to rotate at a high speed when retracting, and the driving shaft 12 is used for bearing the torsional force applied by the retracting system.

In some examples, the drive shaft 12 may interface with the retraction system 2. In some examples, the interface of the proximal end portion 11a may be of a mechanical construction. For example, the mechanical structural interface may be snap-fit, screw-fit, socket-and-spigot, groove-and-socket, and the like.

In some examples, the drive shaft 12 is flexible. In this case, the transmission shaft 12 can be adapted to the sheath 11 to travel in a curved blood vessel, avoiding damage to the blood vessel.

Additionally, in some examples, the drive shaft 12 may have a spring structure and a cover layer coated on the spring structure.

In some examples, the spring structure may be at least one of a coil spring, a truncated cone scroll spring, a torsion bar spring, a disc spring, an annular spring, and a leaf spring. In some examples, the spring structure may be formed by a hollow coil spring. In addition, in some examples, the spring structure may also be formed of at least one selected from an alloy, carbon, rubber, and resin.

In some examples, the spring structure may be formed of two layers of springs, an inner spring structure and an outer spring structure. In this case, the reliability of the spring structure can be improved, particularly, the transmission shaft 12 is less likely to be broken when being drawn and retracted by the retraction system.

In some examples, the outer spring structure may be located on an outer layer of the spring structure, the inner spring structure may be located on an inner layer of the spring structure, and the outer spring structure may be closely attached to the inner spring structure. In some examples, the outer spring structure may be secured to the inner spring structure by an adhesive. In some examples, the spacing between adjacent springs in the inner spring structure is smaller than the spacing between adjacent springs in the outer spring structure.

In addition, in some examples, the spacing of adjacent springs in the outer spring structure becomes larger from the proximal end portion 11a to the distal end portion 11b of the sheath 11. Thereby, the flexibility of the outer spring structure near the distal end portion 11b can be ensured to improve the movement of the transmission shaft 12 within the sheath 11, and the supporting function of the outer spring structure of the proximal end portion 11a can also be improved to facilitate the retraction of the transmission shaft 12.

In some examples, the cover layer coated on the spring structure may be a thin film. In some examples, the film may be formed of at least one of polyvinylpyrrolidone, polyoxyethylene, polyphenylene oxide, and maleic acid. In this case, the cover layer can be reduced from causing damage to the patient's tissue, such as the vascular structure.

Additionally, in some examples, the cover layer may be a protective layer for reinforcing the spring structure. In this case, the spring structure can be reinforced by the protective layer, so that the protective layer is less likely to be deformed. In some examples, the protective layer may be at least one of zinc, chromium, cadmium, copper, nickel, tin, silver, and a zinc-titanium alloy. In addition, in some examples, the protective layer may also be a chemical protective layer obtained by an oxidation treatment, a phosphating treatment, or a harmless painting treatment.

In some examples, the contact between the drive shaft 12 and the buffer layer 111 may be a line contact. In this case, the frictional force between the transmission shaft 12 and the buffer layer 111 can be further reduced. Of course, in practice, the contact between the shaft 12 and the cushion layer 11 has a certain contact area, and it is not easy to form a line contact, but the line contact is formed between the shaft 12 and the cushion layer 11.

In some examples, the drive shaft 12 of the ultrasound catheter 1 may include a signal wire (not shown) connected to the ultrasound transducer. In some examples, the signal line may communicate the electrical signal obtained by the ultrasound transducer to an extracorporeal device, such as a host processing system. In some examples, the signal line may be placed in a hollow location of a spring structure within the drive shaft 12, which can improve signal transmission through a metal shield of the spring structure.

In some examples, the drive shaft 12 in the ultrasound catheter 1 may form sliding friction with the buffer layer 111 in the sheath 11 as the drive shaft 12 travels in the sheath 11. The smaller the friction force between the transmission shaft 12 and the buffer layer 111, the easier the transmission shaft 12 proceeds within the sheath 11, thereby more facilitating the ultrasonic transducer to form a uniform image.

In some examples, the ultrasound catheter 1 of the present disclosure is not limited to use within intravascular ultrasound catheters, but may be used in other interventional treatment devices that require retraction or advancement. Generally, an interventional medical device is inserted into a human body or a natural orifice by a surgical method, and is treated or examined for a short time, and is removed after the treatment or examination is completed. In some other interventional medical instruments like image collection, the transmission shaft is required to be used for advancing or retracting, and the clarity of collected pictures can be enhanced through the catheter disclosed herein, and meanwhile, the convenience in use is greatly improved.

In the ultrasound catheter 1 according to the present embodiment, an ultrasound probe having an ultrasound transducer may be provided separately, and in this case, the ultrasound probe may be disposed so as to be connected to the drive shaft 12. In this case, the drive shaft may be rotated back along with the ultrasound probe during the retraction process. Meanwhile, the ultrasonic transducer arranged on the ultrasonic probe can generate ultrasonic signals in the retraction process, the ultrasonic signals are transmitted in human tissues, and the ultrasonic transducer can receive reflected echo signals and convert the echo signals into electric signals.

While the present disclosure has been described in detail in connection with the drawings and examples, it should be understood that the above description is not intended to limit the disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from the true spirit and scope of the disclosure, which fall within the scope of the disclosure.

Claims (10)

1. An intravascular ultrasound catheter having a spring structure, comprising:

a sheath and a drive shaft, the sheath having a cushioning layer and an outer layer disposed on and covering the cushioning layer, the sheath having a guide lumen, the sheath having a proximal portion and a distal portion contiguous with the proximal portion, the cushioning layer being positioned between the outer layer and the drive shaft; the transmission shaft is provided with an ultrasonic transducer, the transmission shaft is in contact with a buffer layer of the sheath tube, the transmission shaft is provided with a spring structure, the spring structure is formed by two layers of springs, namely an inner spring structure and an outer spring structure, the outer spring structure is fixed on the inner spring structure through an adhesive, the inner spring structure is positioned on the inner layer of the spring structure, the outer spring structure is positioned on the outer layer of the spring structure, the distance between adjacent springs in the outer spring structure is gradually increased from the proximal end part to the distal end part, and the transmission shaft forms sliding friction with the sheath tube through the buffer layer.

2. The intravascular ultrasound catheter of claim 1,

the transmission shaft is also provided with a covering layer coated on the spring structure, the covering layer is a film coated on the spring structure, and the film is formed by at least one of polyvinylpyrrolidone, polyoxyethylene, polyphenylene oxide and maleic acid.

3. The intravascular ultrasound catheter of claim 2,

the covering layer is a protective layer used for reinforcing the spring structure, and the protective layer is at least one of zinc, chromium, cadmium, copper, nickel, tin, silver and zinc-titanium alloy.

4. The intravascular ultrasound catheter of claim 1,

the buffer layer and the outer layer are jointed in a hot melting welding mode, and the hot melting welding mode is at least one of resistance heating welding, infrared heating welding, laser hot melting welding and ultrasonic welding.

5. The intravascular ultrasound catheter of claim 1,

the surface of the outer layer is coated with a coating layer formed of at least one selected from the group consisting of polyvinylpyrrolidone, polyoxyethylene, polyphenylene oxide, and maleic acid.

6. The intravascular ultrasound catheter of claim 1,

the sheath has an outer diameter that gradually decreases from the proximal end portion to the distal end portion.

7. The intravascular ultrasound catheter of claim 1,

the sheath tube has flexibility, and the end of the distal end part of the sheath tube is in a circular arc shape.

8. The intravascular ultrasound catheter of claim 1,

the drive shaft is movable along a guide lumen of the sheath.

9. The intravascular ultrasound catheter of claim 1,

the spring structure is at least one of a helical spring, a truncated cone volute spring, a torsion bar spring, a disc spring, an annular spring and a plate spring.

10. The intravascular ultrasound catheter of claim 1,

the transmission shaft comprises a signal wire connected with the ultrasonic transducer, and the signal wire is arranged in the hollow position of the spring structure in the transmission shaft.

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