Expandable catheter sheath and methods of using same

Abstract

The application discloses an expandable catheter sheath and a use method thereof. The expandable catheter sheath comprises a catheter assembly and a hemostatic valve arranged at one end of the catheter assembly. The catheter assembly comprises an expansion tube and an outer tube sleeved on the expansion tube. The expansion tube is internally provided with an expansion cavity, and at least one branch pipe is communicated with the expansion cavity. Fluid flows into or out of the expansion cavity through the branch pipe. When the fluid flows into the expansion cavity through the branch pipe, the expansion tube expands and props open the outer tube, so that the outer diameter of the catheter assembly is increased. When the fluid flows out of the expansion cavity through the branch pipe, the expansion tube and the outer tube contract, so that the outer diameter of the catheter assembly is reduced. The expansion tube with the expansion cavity is arranged, and the fluid is filled or extracted into the expansion cavity, so that the expansion range of the catheter sheath is controlled, and the catheter sheath can enter and exit the blood vessel with a smaller diameter. Meanwhile, medical staff can flexibly control the expansion degree of the expandable catheter sheath according to actual needs, and the application range is wide.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more particularly to an expandable catheter sheath and its method of use. Background Technology

[0002] Currently, cardiovascular disease treatment techniques include drug therapy, surgery, and interventional therapy. Among these, interventional cardiovascular therapy is widely used in clinical practice due to its advantages such as minimal invasiveness, high safety, and excellent treatment outcomes. Interventional cardiovascular therapy is a technique that uses vascular puncture to enter the heart chambers or blood vessels to perform diagnosis or treatment.

[0003] Catheter sheaths are used to establish vascular access in cardiovascular interventional procedures to facilitate the insertion of interventional / diagnostic instruments into the patient's blood vessels. Currently, the most common catheter sheaths have a fixed outer diameter, which cannot cover the inferior vena cava diameter of all patients or the aorta with calcification in its vessel walls. This is especially true for patients in Asian countries whose inferior vena cava is often narrow, potentially causing vascular injury and hindering suture. Furthermore, in some elderly patients with calcified aortas, inserting a large-diameter catheter sheath may cause the calcified plaques to dislodge. In addition, the catheter sheath is the first instrument inserted into the blood vessel and the last to be withdrawn, resulting in a relatively long time spent in the vessel. Prolonged large-diameter dilation of the blood vessel can easily cause vasospasm, increasing the likelihood of surgical complications.

[0004] In response, some expandable catheter sheaths have been developed and put into clinical use. However, according to patent document CN206372159U, most expandable catheter sheaths expand under force after external instruments are inserted, and the expansion range is limited. Moreover, there is a possibility that when external instruments are inserted into the catheter sheath, they may not be able to expand the catheter sheath properly due to the pressure of the blood vessel wall, thus becoming stuck.

[0005] Therefore, how to improve the technical defects existing in the prior art has always been a problem that ordinary people skilled in the art need to solve. Summary of the Invention

[0006] The purpose of this invention is to provide an expandable catheter sheath and its method of use. The expandable catheter sheath can enter and exit blood vessels with a small diameter, and medical staff can flexibly control the degree of expansion of the expandable catheter sheath according to actual needs, making it widely applicable.

[0007] The technical solution provided by this invention is as follows:

[0008] An expandable catheter sheath, comprising:

[0009] Catheter assembly and hemostatic valve located at one end of the catheter assembly;

[0010] The catheter assembly includes an expansion tube and an outer tube sleeved on the expansion tube;

[0011] The expansion tube is provided with an expansion cavity, and at least one branch tube is connected to the expansion cavity, through which fluid flows into or out of the expansion cavity;

[0012] When fluid flows into the expansion chamber through the branch pipe, the expansion pipe expands and stretches the outer pipe, increasing the outer diameter of the conduit assembly;

[0013] When fluid flows out of the expansion chamber through the branch pipe, the expansion pipe and the outer pipe contract, reducing the outer diameter of the conduit assembly.

[0014] In some embodiments, the expansion tube has a rolled wall structure and overlapping portions;

[0015] When fluid flows into the expansion chamber through the branch pipe, the expansion pipe expands, and the overlapping portion of the expansion pipe walls decreases.

[0016] When fluid flows out of the expansion chamber through the branch pipe, the expansion pipe contracts, and the overlap of the expansion pipe walls increases.

[0017] In some embodiments, the expansion tube is configured to form a first channel through which external instruments can pass, and the first channel is connected to a drain pipe.

[0018] In some embodiments, the expansion tubes are spirally distributed along the central axis of the outer tube;

[0019] When fluid flows into the expansion chamber through the branch pipe, the expansion pipe expands, and the diameter and pitch of the spiral formed by the expansion pipe increase.

[0020] When fluid flows out of the expansion chamber through the branch pipe, the expansion pipe contracts, and the diameter and pitch of the spiral formed by the expansion pipe decrease.

[0021] In some embodiments, the conduit assembly further includes an inner tube;

[0022] The expansion tube forms a first channel, the inner tube passes through the first channel, one end is located at the hemostatic valve, and the other end is fixedly connected to the outer tube.

[0023] The inner tube is enclosed to form a second channel through which external instruments can pass, and the second channel is connected to a drain pipe.

[0024] In some embodiments, the conduit assembly further includes a stress diffusion tube;

[0025] The stress diffusion tube is sleeved on the outer tube, with one end located on the hemostatic valve and the other end fixed to the outer wall of the outer tube, in order to strengthen the connection between the outer tube and the hemostatic valve.

[0026] In some embodiments, the expansion tube is made of a non-compliant material, while the outer tube is made of a compliant material.

[0027] In some embodiments, the fluid flowing into or out of the dilation cavity via the branch tube is sterile saline containing contrast agent.

[0028] In some embodiments, the branch pipe is equipped with a valve, and by controlling the opening and closing of the valve, the branch pipe can be opened or closed.

[0029] The present invention also provides a method for using an expandable catheter sheath.

[0030] The expandable catheter sheath includes an expansion tube and an outer tube sleeved on the expansion tube. The expansion tube has an expansion cavity inside, and at least one tube is connected to the expansion cavity. The expansion tube also forms a channel through which external instruments can pass.

[0031] The expandable catheter sheath guides the fluid in the expansion lumen to the outside through the branch tube, so that the outer diameter of the outer tube is at its minimum value, so that the expandable catheter sheath can enter the delivery state.

[0032] The expandable catheter sheath guides external fluid into the expansion cavity through the branch tube, gradually increasing the outer diameter of the outer tube and the size of the channel to the required size, so that the expandable catheter sheath can be used by external instruments.

[0033] The technical effects of this invention are as follows:

[0034] 1. In this patent, by setting an expansion tube with an expansion cavity and filling or withdrawing fluid into the expansion cavity, the expansion range of the catheter sheath can be controlled, allowing the catheter sheath to enter and exit blood vessels with a smaller diameter. Simultaneously, medical personnel can flexibly control the degree of expansion of the expandable catheter sheath according to actual needs, which is more conducive to the entry and exit of external instruments and has a wide range of applications.

[0035] 2. In this patent, the dilator tubes are spirally distributed along the central axis of the outer tube. Thus, when the dilator tubes expand, the diameter and pitch of the spiral line increase, allowing the outer tube to expand more evenly and completely. This also results in more even force distribution on the outer tube, leading to better vascular dilation. Furthermore, to further improve the smoothness of external instrument insertion into the catheter sheath, an inner tube is inserted within the first channel formed by the spirally distributed dilator tubes. External instruments are inserted through the second channel formed by the inner tube, effectively preventing the external instruments from being stuck by the spirally distributed dilator tubes.

[0036] 3. In this patent, the dilator is made of a non-compliant material, which allows for expansion of the outer diameter of the outer tube while providing less radial support. Conversely, the outer tube is made of a compliant material, ensuring a smoother outer surface before and after dilation, effectively reducing damage to blood vessels from the catheter sheath.

[0037] 4. In this patent, before the dilatable catheter sheath enters the blood vessel, the fluid in the dilatation lumen is first guided to the outside through the branch tube. This is to avoid the presence of air in the dilatation lumen, which would prevent the catheter sheath from entering the patient's blood vessel with the smallest diameter and affect the performance of the catheter sheath. Attached Figure Description

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0039] Figure 1 This is a schematic diagram of the expandable catheter sheath provided by the present invention;

[0040] Figure 2 This is a three-dimensional structural diagram of the outer tube, expansion tube, and inner tube provided by the present invention;

[0041] Figure 3 This is a schematic diagram of the cross-sectional structure of the outer tube, expansion tube, and inner tube provided by the present invention.

[0042] Explanation of icon numbers:

[0043] 110. Expansion tube; 111. Expansion cavity; 112. First channel; 120. Outer tube; 130. Branch tube; 140. Inner tube; 141. Second channel; 150. Drain tube; 160. Stress diffusion tube; 170. Valve;

[0044] 200. Hemostatic valve. Detailed Implementation

[0045] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0047] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0048] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0049] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various components of the invention are relative rather than absolute. These descriptions are appropriate when these components are in the positions shown in the drawings. If the descriptions of the positions of these components change, these directional indications also change accordingly.

[0051] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0052] According to a specific embodiment provided by the present invention, see [link to specific embodiment]. Figures 1 to 3 An expandable catheter sheath and its method of use are disclosed. Specifically, the expandable catheter sheath may include a catheter assembly and a hemostatic valve 200 disposed at one end of the catheter assembly. The catheter assembly may include a dilator 110 and an outer tube 120 sleeved on the dilator 110. The dilator 110 has an dilator cavity 111, and at least one branch tube 130 is connected to the dilator cavity 111, allowing fluid to flow into or out of the dilator cavity 111 via the branch tube 130. When fluid flows into the dilator cavity 111 via the branch tube 130, the dilator 110 expands and expands the outer tube 120, increasing the outer diameter of the catheter assembly. When fluid flows out of the dilator cavity 111 via the branch tube 130, the dilator 110 contracts, and the outer tube 120, which was previously expanded by force, re-closes, reducing the outer diameter of the catheter assembly.

[0053] It is worth noting that, see Figure 2 and Figure 3 The area enclosed by the expansion tube 110 has a channel for external instruments to pass through. When the expansion tube 110 expands, the channel also expands; when the expansion tube 110 contracts, the channel also contracts.

[0054] In this embodiment, by providing an expansion tube 110 with an expansion cavity 111 and filling or withdrawing fluid into the expansion cavity 111, the expansion range of the catheter sheath can be controlled, allowing the catheter sheath to enter and exit the patient's blood vessels with a smaller diameter. Simultaneously, medical personnel can flexibly control the degree of expansion of the expandable catheter sheath according to actual needs, which is more conducive to the entry and exit of external instruments and has a wide range of applications.

[0055] It is worth mentioning that the expansion limit of the catheter sheath provided in this embodiment depends on the extensibility of the expansion tube 110 and the outer tube 120. It can be flexibly set according to actual needs during manufacturing. It will not be elaborated here, and all of them are within the protection scope of this invention.

[0056] In existing technologies, the most common expandable catheter sheaths expand under force after the insertion of external instruments, which limits their expansion range. However, the catheter sheath provided in this embodiment can change the degree of expansion by altering the volume of the filling fluid, thus having a wider range of applications.

[0057] Furthermore, when medical staff use a catheter sheath that expands due to the insertion of external instruments, the insertion speed is relatively slow because the external instruments are subjected to pressure from the blood vessel wall, and there is also a risk of them getting stuck. However, when medical staff use the catheter sheath provided in this embodiment, they can first expand the channel inside the catheter sheath to a suitable size for the insertion of external instruments, and then directly insert the external instruments. The insertion speed is fast, the operation is simple, and the safety is high.

[0058] Specifically, see Figure 1In this embodiment, the number of branch pipes 130 can be one. When it is necessary to fill the expansion cavity 111 with fluid, the branch pipe 130 is used as a pipeline for filling the expansion cavity 111 with fluid; when it is necessary to extract the fluid from the expansion cavity 111, the branch pipe 130 is used as a pipeline for extracting the fluid from the expansion cavity 111.

[0059] Of course, there can also be two branch pipes 130. In this case, one branch pipe 130 can be used as a dedicated pipeline for filling the expansion chamber 111 with fluid, and the other branch pipe 130 can be used as a dedicated pipeline for extracting fluid from the expansion chamber 111.

[0060] In one embodiment, the expansion tube 110 has a rolled-up wall structure with overlapping portions. When fluid flows into the expansion chamber 111 through the branch pipe 130, the expansion tube 110 expands, and the overlapping portion of the expansion tube 110 walls decreases; when fluid flows out of the expansion chamber 111 through the branch pipe 130, the expansion tube 110 contracts, and the overlapping portion of the expansion tube 110 walls increases.

[0061] At this point, the channel within the area enclosed by the dilator tube 110, which allows external instruments to pass through, is the first channel 112 formed by the dilator tube 110. Thus, when medical personnel fill the dilation cavity 111 with fluid, the overlapping sections of the dilator tube 110 walls unfold, providing a certain supporting force, thereby dilating the patient's blood vessels along with the outer tube 120. Simultaneously, after the overlapping sections of the dilator tube 110 walls unfold, the cross-sectional area of ​​the first channel 112 formed by them also increases, facilitating the insertion of external instruments.

[0062] Preferably, see Figure 1 The first channel 112 is connected to an emptying tube 150 to expel air from the first channel 112, preventing air from entering the blood vessels and further improving the safety of the operation.

[0063] In one embodiment, see Figure 2 and Figure 3 The expansion tube 110 is spirally distributed along the central axis of the outer tube 120. When the fluid flows into the expansion chamber 111 through the branch pipe 130, the expansion tube 110 expands, and the diameter and pitch of the spiral formed by the expansion tube 110 increase; when the fluid flows out of the expansion chamber 111 through the branch pipe 130, the expansion tube 110 contracts, and the diameter and pitch of the spiral formed by the expansion tube 110 decrease.

[0064] Because the diameter and pitch of the spiral formed by the expansion tube 110 provided in this embodiment increase when it expands, and it has a certain supporting force, it can expand the outer tube 120 more evenly and completely. At the same time, the force on the outer tube 120 is also more even, resulting in a better dilation effect on blood vessels.

[0065] Specifically, before expansion, the diameter of the spiral formed by the expansion tube 110 is 4-8 mm; after expansion, the diameter of the spiral formed by the expansion tube 110 is 6-12 mm.

[0066] To further enhance the supporting effect of the dilator 110 on the outer tube 120 in the above embodiments, in a preferred embodiment, the spirally distributed dilator 110 has at least one axial tube extending along the central axis of the outer tube 120 on the side facing the outer tube 120. Specifically, the number of axial tubes can be two, three, or four, etc., and they are evenly spaced to ensure that the outer tube 120 receives a more uniform supporting force, resulting in better dilation of the catheter assembly and making it more conducive for the catheter sheath to open the patient's blood vessels.

[0067] In one embodiment, the expansion tube 110 may include at least two axial branch tubes extending along the central axis of the outer tube 120, and a first annular branch tube connecting the end of the axial branch tube away from the hemostatic valve 200 and a second annular branch tube connecting the end of the axial branch tube near the hemostatic valve 200.

[0068] When fluid flows into the dilation chamber 111 through the branch pipe 130, the axial branch pipe, the first annular branch pipe, and the second annular branch pipe all expand, thereby causing the outer tube 120 to dilate. At this time, the axial branch pipe can provide sufficient support to the outer tube 120, allowing it to expand while simultaneously providing sufficient force to dilate the patient's blood vessels. Specifically, the number of axial branch pipes can be three, four, or five, etc., and they are evenly spaced, so that the dilation tube 110 can more evenly and completely expand the outer tube 120. At the same time, the force on the outer tube 120 is also more even, resulting in a better dilation effect on the blood vessels.

[0069] Conversely, when the fluid flows out of the expansion chamber 111 through the branch pipe 130, the axial branch pipe, the first annular branch pipe, and the second annular branch pipe will all contract.

[0070] In one embodiment, the length of each axial branch tube is different. Thus, when fluid flows into the dilation chamber 111 through the branch tube 130, the dilation tube 110 will bend to varying degrees, allowing the catheter sheath to adapt to complex vascular structures over a wider range. Of course, in actual production, the specific length of each axial branch tube should be flexibly set according to actual needs, and will not be elaborated here.

[0071] It is worth noting that the bendable catheter sheath provided in this embodiment is suitable for inserting external instruments into a patient's cerebral blood vessels. If the catheter sheath is suitable for inserting external instruments into a patient's aorta or vein, then the catheter sheath does not need to have a bendable function, and there is no need to set up axial branches of different lengths.

[0072] In the above embodiments, the expansion tubes 110 arranged in a spiral or including axial branch tubes, a first annular branch tube, and a second annular branch tube can all be configured to form a first channel 112. In this case, external instruments can be directly inserted into the first channel 112; however, there is also a risk that the external instruments may be stuck in the expansion tubes 110.

[0073] In one embodiment, see [link to relevant documentation]. Figure 2 and Figure 3 The catheter assembly also includes an inner tube 140, which passes through the first channel 112, with one end connected to the hemostatic valve 200 and the other end fixedly connected to the outer tube 120. Preferably, the inner tube 140 and the outer tube 120 are fixed by adhesive application or welding.

[0074] In this embodiment, the channel within the area enclosed by the dilator 110, which allows external instruments to pass through, is the second channel 141 formed by the inner tube 140. Thus, when medical personnel fill the dilator 111 with fluid, the outer tube 120 is expanded by the dilator 110, causing the fixedly connected inner tube 140 to expand as well. This expands the patient's blood vessels while simultaneously increasing the cross-sectional area of ​​the second channel 141 formed by the inner tube 140, facilitating the insertion of external instruments.

[0075] Preferably, the inner tube 140 and the dilator tube 110 are fixedly connected. In this way, when the dilator tube 110 expands, the inner tube 140 is more easily moved and expands along with the dilator tube 110. In addition, this arrangement can also effectively fix the dilator tube 110, optimizing the structural design of the catheter sheath.

[0076] Specifically, the end of the inner tube 140 furthest from the hemostatic valve 200 is fixedly connected to both the outer tube 120 and the expansion tube 110, or the outer wall of the inner tube 140 is fixedly connected to the expansion tube 110. This is not limited; any method that allows the inner tube 140 to be fixedly connected to the expansion tube 110 is acceptable and falls within the scope of this invention. Preferably, the inner tube 140 and the expansion tube 110 are fixed using adhesive or welding.

[0077] Further, see Figure 1 The second channel 141 is connected to an emptying tube 150 to expel air from the second channel 141, preventing air from entering the blood vessels and further improving the safety of the operation.

[0078] In a preferred embodiment, see Figure 1 The catheter assembly also includes a stress diffusion tube 160. The stress diffusion tube 160 is sleeved on the outer tube 120, with one end located at the hemostatic valve 200 and the other end fixed to the outer wall of the outer tube 120, in order to strengthen the connection between the outer tube 120 and the hemostatic valve 200.

[0079] Furthermore, the dilator 110 is made of a non-compliant material, which allows it to provide less radial support to the outer tube 120, thereby expanding the outer tube 120 and increasing the outer diameter of the catheter assembly as it expands. In addition, the non-compliant material also facilitates the formation of a first channel 112 by the dilator 110, allowing external instruments to be inserted or the inner tube 140 to pass through.

[0080] Among them, non-compliant materials are preferably PET, PC, PETG, PCTG and other materials.

[0081] In contrast, the outer tube 120 is made of a compliant material, which ensures that the outer tube 120 maintains a relatively smooth outer surface before and after dilation, effectively reducing damage to the patient's blood vessels by the catheter sheath.

[0082] It is worth noting that when selecting compliant materials for the appearance, the cross-section of the outer tube 120 should be circular or near-circular before and after expansion to further reduce the damage of the catheter sheath to the patient's blood vessels.

[0083] In addition, the inner tube 140 mentioned in the above embodiments should also be made of a compliant material to give it a certain radial support force. In this way, a second channel 141 with a cross-sectional area that increases with the expansion of the expansion tube 110 and the outer tube 120 can be formed, which facilitates the insertion of external instruments.

[0084] Among them, compliant materials are preferably elastomers such as PU and Pebax.

[0085] Furthermore, the fluid flowing into or out of the dilation chamber 111 through the branch tube 130 is sterile saline containing contrast agent. In this way, medical staff can directly see the position of the catheter assembly and whether it is dilated in place, which facilitates the surgical operation, reduces the surgical risk to a certain extent, and ensures high safety.

[0086] As a preferred option, see Figure 1 The branch tube 130 is equipped with a valve 170. By controlling the opening and closing of the valve 170, the branch tube 130 can be opened or closed. In this way, after the medical staff has filled the dilation chamber 111 with fluid, they can directly close the valve 170 to prevent the fluid from flowing out and affecting the dilation effect of the catheter sheath.

[0087] Of course, see Figure 1 The venting pipe 150 mentioned in the above embodiments may also be equipped with a valve 170. By controlling the opening and closing of the valve 170, the venting pipe 150 can be opened or closed. In this way, after medical staff have vented the gas in the channel through which external instruments can pass, they can directly close the valve 170 to prevent external gas from re-entering the channel through the valve 170.

[0088] The valve 170 located in the branch pipe 130 and the valve 170 located in the drain pipe 150 can preferably be a three-way plug valve.

[0089] The present invention also provides a method of using an expandable catheter sheath, which specifically includes an expansion tube 110 and an outer tube 120 sleeved on the expansion tube 110. The expansion tube 110 has an expansion cavity 111, and at least one tube 130 is connected to the expansion cavity 111. In addition, the expansion tube 110 forms a channel for external instruments to pass through. Preferably, the channel formed by the expansion tube 110 should be connected to a drain tube 150.

[0090] At this point, the specific steps for using the dilatable catheter sheath include:

[0091] S1. The expandable catheter sheath guides the fluid in the expansion chamber 111 to the outside through the branch tube 130, so that the outer diameter of the outer tube 120 is at its minimum value, so that the expandable catheter sheath can enter the delivery state. Specifically, the delivery state of the expandable catheter sheath is the state when the expandable catheter sheath is moved to the target position.

[0092] In practical use, the dilatable catheter sheath must be used in conjunction with a dilator. First, medical staff insert the dilator into the dilatable catheter sheath. Then, sterile heparinized saline solution is injected into the channel through the evacuation tube 150 to expel any air from the channel. After all the air has been expelled, the dilatable catheter sheath is then inserted into the patient's blood vessel. This effectively prevents air from entering the patient's blood vessels and endangering their life and health.

[0093] S2. After removing the dilator, the expandable catheter sheath guides external fluid into the dilation chamber 111 through the branch tube 130, so that the outer diameter and channel size of the outer tube 120 gradually increase to the required size, so that the expandable catheter sheath can be used in a state where external instruments can pass through.

[0094] Thus, medical personnel can use this expandable catheter sheath to insert external instruments into the patient's blood vessels for treatment. The inserted external instruments are mostly balloon dilation catheters or heart valve delivery systems; of course, other instruments may also be used, which will not be detailed here, but are all within the scope of this invention.

[0095] After treatment, the dilatable catheter sheath guides the fluid in the dilation chamber 111 to the outside through the branch tube 130, so that the outer diameter of the outer tube 120 is at its minimum value, so that the dilatable catheter sheath can leave the patient's blood vessel.

[0096] In this embodiment, before the dilatable catheter sheath enters the blood vessel, the fluid within the dilatation lumen is first drained to the outside through a branch tube. This is to prevent air from remaining within the dilatation lumen, which would prevent the catheter sheath from entering the blood vessel at its minimum diameter and affect its performance. Therefore, medical personnel should ideally aspirate several times before inserting the dilatable catheter sheath into the blood vessel to remove all air from the dilatation lumen.

[0097] Preferably, the fluid used to enter and exit the expansion cavity 111 contains a contrast agent, so that medical staff can use the contrast agent to image and promptly determine whether the fluid in the expansion cavity 111 has been fully filled or drained, making the operation convenient.

[0098] In actual production, a fluid pressure detection device can also be installed inside the expansion cavity 111. In this case, medical personnel can determine whether the fluid inside the expansion cavity 111 has been fully filled or completely drained based on the detected fluid pressure. Of course, besides the two implementation methods described above, other structural arrangements can also be used to assist medical personnel in determining whether the fluid inside the expansion cavity 111 has been fully filled or completely drained. These will not be elaborated upon here, and all are within the scope of protection of this invention.

[0099] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0100] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An expandable catheter sheath, characterized by, The application relates to a catheter assembly and a hemostatic valve arranged at one end of the catheter assembly. The catheter assembly comprises an expansion tube, an inner tube and an outer tube sleeved on the expansion tube. The expansion tube is provided with an expansion cavity, and at least one branch pipe is connected to the expansion cavity, so that fluid can flow into or out of the expansion cavity through the branch pipe; the expansion tube is provided with a first channel, the inner tube is arranged in the first channel, one end of the inner tube is arranged in the hemostatic valve, and the other end of the inner tube is fixedly connected to the outer tube; the inner tube is provided with a second channel for external instruments to pass through, and the second channel is connected to a discharge pipe. When fluid flows into the expansion cavity through the branch pipe, the expansion tube expands, the outer tube is expanded and the inner tube is expanded, so that the outer diameter of the catheter assembly is increased, the cross-sectional area of the second channel is increased, and the external instruments are facilitated to pass in; when fluid flows out of the expansion cavity through the branch pipe, the expansion tube and the outer tube are contracted, so that the outer diameter of the catheter assembly is reduced. The wall of the expansion tube is a roll wall structure, and the wall has overlapping parts.

2. The expandable catheter sheath of claim 1, wherein , When fluid flows into the expansion cavity through the branch pipe, the expansion tube expands, and the overlapping parts of the wall of the expansion tube are reduced. When fluid flows out of the expansion cavity through the branch pipe, the expansion tube is contracted, and the overlapping parts of the wall of the expansion tube are increased.

3. The expandable catheter sheath according to claim 2, wherein the first channel is connected to a discharge pipe.

4. The expandable catheter sheath according to claim 1, wherein the expansion tube is spirally distributed along the central axis of the outer tube. When fluid flows into the expansion cavity through the branch pipe, the expansion tube expands, and the diameter and pitch of the spiral line formed by the expansion tube are increased. When fluid flows out of the expansion cavity through the branch pipe, the expansion tube is contracted, and the diameter and pitch of the spiral line formed by the expansion tube are reduced.

5. The expandable catheter sheath according to any one of claims 1-4, wherein the catheter assembly further comprises a stress diffusion tube. The stress diffusion tube is sleeved on the outer tube, one end of the stress diffusion tube is arranged in the hemostatic valve, and the other end of the stress diffusion tube is fixed to the outer side wall of the outer tube, so as to strengthen the connection strength of the outer tube and the hemostatic valve.

6. The expandable catheter sheath according to any one of claims 1-4, wherein the expansion tube is made of a non-compliant material, and the outer tube is made of a compliant material.

7. The expandable catheter sheath according to any one of claims 1-4, wherein the fluid flowing into or out of the expansion cavity through the branch pipe is sterile normal saline containing contrast agent.

8. The expandable catheter sheath according to any one of claims 1-4, wherein the branch pipe is provided with a valve, and the branch pipe is opened or blocked by controlling the opening and closing of the valve. ​ ​ ​ ​ ​ ​ ​

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