Microcatheter with dynamically adjustable distal tip angle

Abstract

The application discloses a micro catheter capable of dynamically adjusting a distal end outlet angle. The micro catheter capable of dynamically adjusting the distal end outlet angle comprises a catheter base body, the catheter base body is provided with a first channel and a second channel arranged along an axial direction; the first channel is a fixed cavity channel used for guiding a first guide wire to pass through; the second channel comprises a side cavity and an axial guide cavity which are in butt joint communication, and an auxiliary moving cavity is arranged in the second channel and used for guiding the auxiliary moving cavity to move; one end of the side cavity is in butt joint communication with an end of the axial guide cavity adjacent to the fixed cavity channel, the other end of the side cavity is an outlet end of the second channel, and an inclined turning guide side wall is arranged on an inner wall of the side cavity; the auxiliary moving cavity is provided with a second guide wire channel used for guiding a second guide wire to pass through, and a deformation area arranged in an axial direction is arranged at a distal end of the auxiliary moving cavity; a pulling wire driving mechanism is connected to the catheter base body, and a distal end of the pulling wire is connected to the deformation area of the auxiliary moving cavity. The application realizes multi-angle composite adjustment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of surgical instruments, in particular to a microcatheter. BACKGROUND

[0002] In cardiovascular intervention, the guide wire crossing of branch vessels (especially acute angle branches) is a key step for successful operation. The traditional technology adopts a combination scheme of double-lumen microcatheter and reverse guide wire, the core principle of which is to accommodate two guide wires entering the main branch and branch vessels respectively through the double-lumen structure to enhance the adaptability to complex vascular anatomy. However, the existing technology has the following significant limitations:

[0003] Fixed guide wire exit angle: the guide wire lumen exit angle of the traditional double-lumen microcatheter is a fixed design (usually pre-shaped bending), which cannot be adjusted dynamically according to the intraoperative vascular anatomy. When the branch vessel angle exceeds the preset range of the catheter (such as > 70°), the guide wire is difficult to accurately enter the target branch, resulting in an increased failure rate of the operation. Clinical research: Smith et al. (2020) pointed out in the Journal of Interventional Cardiology that when the branch angle exceeds 70°, the success rate of guide wire crossing of the traditional double-lumen catheter decreases to 62%, and blood vessel perforation is easily caused by the excessively high rigidity of the front end of the guide wire (occurrence rate 8%). The Finecross®MG double-lumen microcatheter instruction manual of Terumo Company clearly marks that the upper limit of the applicable branch angle is 60°.

[0004] High structural redundancy: difficult to be compatible with small branch vessels. For example, the Chinese patent with publication number CN113456986A discloses a double-lumen microcatheter, the guide wire exit angle of which cannot be adjusted intraoperatively. SUMMARY

[0005] In view of the problems existing in the prior art, the present application provides a microcatheter for dynamically adjusting the exit angle of the distal end, which has solved at least one of the above technical problems.

[0006] The technical scheme of the present application is: a microcatheter for dynamically adjusting the exit angle of the distal end, comprising a catheter base body, the catheter base body is provided with a first channel and a second channel arranged along the axial direction;

[0007] The first channel is a fixed lumen, which is a first guide wire channel for guiding the first guide wire to pass through;

[0008] The second channel includes a side lumen and an axial guide lumen, and the second channel is provided with an auxiliary moving lumen for guiding the auxiliary moving lumen to move;

[0009] One end of the side cavity is connected to the end of the axial guide cavity adjacent to the fixed cavity, and the other end of the side cavity is the outlet end of the second channel. The inner wall of the side cavity is provided with a sloping steering guide side wall.

[0010] The auxiliary moving cavity has a second guide wire channel for the second guide wire to pass through, and the distal end of the auxiliary moving cavity is provided with an axially arranged deformation zone.

[0011] The catheter substrate is connected to a traction wire drive mechanism for driving the traction wire to move axially, and the distal end of the traction wire is connected to the deformation zone of the auxiliary moving cavity.

[0012] This invention optimizes the structure of the microcatheter by axially arranging the first and second channels, effectively reducing the overall outer diameter. After the auxiliary moving cavity is exited through the adjustable channel, different guidewire exit angles can be adjusted.

[0013] More preferably, the axially arranged deformation zones are a first deformation zone, a second deformation zone, and a third deformation zone arranged axially from the distal end to the proximal end, with the stiffness of the first deformation zone, the second deformation zone, and the third deformation zone increasing progressively; and the stiffness of the first deformation zone is higher than the stiffness of the other areas on the auxiliary moving cavity except for the first deformation zone, the second deformation zone, and the third deformation zone.

[0014] The axial lengths of the first deformation zone, the second deformation zone, and the third deformation zone increase progressively.

[0015] Multi-angle composite adjustment is achieved by combining an axially arranged deformation zone, an auxiliary moving cavity, and a steering guide sidewall on the side cavity. When the drawing drive mechanism drives the auxiliary moving cavity to move axially, the axially arranged deformation zone extends out of the side cavity in sequence.

[0016] When different deformation zones come into contact with the steering guide sidewall, the different stiffness of the different deformation zones will lead to different steering angles, thereby meeting the requirements of different guide wire exit angles.

[0017] More preferably, the auxiliary moving cavity includes an inner layer, a nickel-titanium alloy braided layer, and an outer covering layer arranged sequentially from the inside to the outside;

[0018] The braiding density of the nickel-titanium alloy braided layer in the first deformation zone, the second deformation zone, and the third deformation zone increases progressively.

[0019] The first deformation zone is further provided with a first polymer layer covering the outer coating layer;

[0020] The second deformation zone is further provided with a second polymer layer covering the outer coating layer;

[0021] The third deformation zone is further provided with a third polymer layer covering the outer coating layer;

[0022] The hardness of the first polymer layer, the second polymer layer, and the third polymer layer increases progressively.

[0023] More preferably, the axial length of the first deformation zone is 1-3 mm, the axial length of the second deformation zone is 3-5 mm, and the axial length of the third deformation zone is 5-10 mm.

[0024] More preferably, the first polymer layer is PEBAX with a hardness of 35D-45D;

[0025] The second polymer layer is PEBAX with a hardness of 45-55D;

[0026] The third polymer layer is PEBAX with a hardness of 55D-75D.

[0027] PEBAX is a thermoplastic polyetheramide elastomer.

[0028] More preferably, the braiding density of the titanium alloy braided layer in the first deformation region is 100-150 pieces / inch;

[0029] The braiding density of the titanium alloy braided layer in the second deformation zone is 150-210 pieces / inch;

[0030] The braiding density of the titanium alloy braided layer in the third deformation zone is 210-250 pieces / inch;

[0031] The auxiliary moving cavity has a weaving density of 100-150 pieces / inch in the region behind the third deformation zone.

[0032] More preferably, the steering guide sidewall is provided with a serrated guide groove;

[0033] The distal sidewall of the auxiliary moving cavity is provided with a serrated structure that engages with the serrated guide groove.

[0034] The anti-torsion and guidance of the auxiliary moving cavity are achieved through the meshing of the serrated guide groove and the serrated teeth.

[0035] More preferably, the wire drawing drive mechanism includes a housing and a ratchet locking mechanism installed in the housing, the ratchet locking mechanism including a ratchet, a locking block, a spring and a limiting block;

[0036] The ratchet is rotatably mounted inside the housing, and a drive component for rotating the ratchet is mounted outside the housing;

[0037] The ratchet is coaxially connected to a winding shaft, and one end of the pull wire is wound around the winding shaft.

[0038] The spring is clamped between the locking block and the limiting block, and a sliding groove for sliding the locking block is installed inside the housing;

[0039] The locking block is provided with toothed protrusions for unidirectionally limiting the ratchet;

[0040] The wire drawing drive mechanism also includes a reset mechanism, which is used to drive the limiting block away from the ratchet.

[0041] More preferably, the reset mechanism includes an unlocking block, which is connected to the housing via a reset spring;

[0042] The unlocking block is provided with an inclined guide rail that is inclined from the outside to the inside towards the ratchet side. The unlocking block is slidably connected to the limiting block through the inclined guide rail. The housing is provided with a sliding groove for the limiting block to slide.

[0043] When the unlocking block is pressed, the unlocking block causes the limiting block to move away from the ratchet.

[0044] When the unlocking block is released, it causes the limiting block to move toward the side adjacent to the ratchet.

[0045] More preferably, the diameter of the drawing wire is 0.1 mm and the material is 304 stainless steel.

[0046] More preferably, a first developing ring is provided on the outer wall of the first channel;

[0047] A second imaging ring is provided on the outer wall of the axial guide cavity adjacent to the side cavity side;

[0048] A third developing ring is provided on the outer wall of the distal end of the auxiliary moving cavity.

[0049] The above-mentioned imaging ring facilitates the positioning of the catheter.

[0050] More preferably, the distal end of the second guidewire is provided with a helical segment, the length of which is 40-50cm;

[0051] The spiral diameter of the spiral segment is 0.4-0.6 mm, and the pitch is 0.02-0.08 mm.

[0052] Traditional guidewires typically have a spiral segment ≤260mm. Extending the spiral segment increases the contact area between the guidewire and the vessel wall, improving the guidewire's stability in acute-angled branches. The contact area between the spiral segment and the vessel wall is increased to approximately 2.3 times that of traditional guidewires, ensuring that the catheter is less prone to kinking during retraction.

[0053] Beneficial effects:

[0054] 1. Dynamic multi-plane adjustment technology

[0055] This invention achieves multi-angle composite adjustment by combining an axially arranged deformation zone, an auxiliary moving cavity, and a steering guide sidewall on the side cavity. When the drawing wire drive mechanism drives the auxiliary moving cavity axially, the first, second, and third deformation zones extend sequentially from the side cavity. When different deformation zones contact the steering guide sidewall, the different stiffnesses of these zones result in different steering angles, thus fulfilling the requirements for different guide wire exit angles.

[0056] This invention features a first imaging ring on the outer wall of the first channel; a second imaging ring on the outer wall of the axial guiding cavity adjacent to the side cavity; and a third imaging ring on the outer wall of the distal end of the auxiliary moving cavity. This combination of the first and second imaging rings facilitates the positioning of the catheter substrate. The combination of the second and third imaging rings also allows for the determination of the position of the auxiliary moving cavity extending from the second channel. Furthermore, the difference in the relative tilt angles of the second and third imaging rings facilitates the determination of the turning direction of the distal end of the auxiliary moving cavity.

[0057] This invention adjusts the axial extension length of the auxiliary movable cavity into the side cavity, thereby adjusting the angle and direction of the outlet of the auxiliary movable cavity into the second channel. The structure of this invention allows for continuous dynamic angle adjustment from 30° to 150°. Clinical simulation trials show that the success rate of guidewire crossing for branches with acute angles >70° is increased from the traditional 62% to 89% (data source: in vitro vascular model testing).

[0058] 2. Guidewire-catheter co-anchoring system

[0059] The distal end of the second guidewire of the present invention is provided with a helical segment, which is longer than that of the traditional helical segment, thereby increasing the contact area between the guidewire and the blood vessel wall and improving the stability of the guidewire in acute-angle branches.

[0060] This invention achieves anti-torsion and guidance of the auxiliary moving cavity through the meshing of the serrated guide groove and the serrated teeth.

[0061] The present invention reduces the risk of catheter displacement to less than 2% by combining the spiral section of the second guidewire with the intermeshing sawtooth guide groove and sawtooth.

[0062] 3. Miniaturized dual-cavity structure

[0063] By axially arranging the first and second channels, the overall outer diameter is effectively reduced. This reduces the outer diameter by 15%, making it compatible with 5F guiding catheters (traditional techniques require ≥6F). Attached Figure Description

[0064] Figure 1 This is a schematic diagram of a specific embodiment 1 of the present invention;

[0065] Figure 2 This is a schematic diagram of a structure during deformation of the first deformation zone in a specific embodiment 1 of the present invention;

[0066] Figure 3 This is a schematic diagram of a structure during deformation of the second deformation zone in a specific embodiment 1 of the present invention;

[0067] Figure 4 This is a schematic diagram of a structure during deformation of the third deformation zone in a specific embodiment 1 of the present invention;

[0068] Figure 5 This is a schematic diagram of the auxiliary moving cavity in a specific embodiment 1 of the present invention;

[0069] Figure 6 This is a partial structural diagram of the sawtooth guide groove in a specific embodiment 1 of the present invention;

[0070] Figure 7 This is a schematic diagram of the drawing drive mechanism according to a specific embodiment 1 of the present invention;

[0071] Figure 8 This is a schematic diagram of the reset mechanism in the unpressed state according to a specific embodiment 1 of the present invention;

[0072] Figure 9 A schematic diagram of the reset mechanism in the pressed state according to specific embodiment 1 of the present invention;

[0073] Figure 10 This is a partial structural schematic diagram of the guide mechanism in specific embodiment 1 of the present invention.

[0074] In the diagram: 1 is the first channel, 2 is the second channel, 21 is the side cavity, and 22 is the serrated guide groove;

[0075] 3 is the auxiliary moving cavity, 31 is the first deformation zone, 32 is the second deformation zone, and 33 is the third deformation zone;

[0076] 4 is the first developing ring, 5 is the second developing ring, and 6 is the third developing ring;

[0077] 7 represents drawn wire;

[0078] 8 is the reset mechanism, 81 is the unlocking block, and 82 is the reset spring;

[0079] 10 is the wire drawing drive mechanism, 101 is the housing, 102 is the drive component, 103 is the ratchet, 104 is the locking block, 105 is the spring, and 106 is the limit block;

[0080] 11 is the guiding mechanism. Detailed Implementation

[0081] See Figures 1 to 10 In specific embodiment 1, a microcatheter with dynamically adjustable distal outlet angle includes a catheter base. The catheter base has a first channel 1 and a second channel 2 arranged along the axial direction. The first channel 1 is a fixed cavity and a first guidewire channel for guiding the first guidewire through. The second channel 2 includes a side cavity 21 that is connected to the axial guide cavity and an axial guide cavity. An auxiliary moving cavity 3 is provided in the second channel 2 for guiding the movement of the auxiliary moving cavity 3. One end of the side cavity 21 is connected to the end of the fixed cavity adjacent to the axial guide cavity, and the other end of the side cavity 21 is the outlet end of the second channel 2. The inner wall of the side cavity 21 is provided with a sloping turning guide sidewall. The auxiliary moving cavity 3 has a second guidewire channel for the second guidewire to pass through, and the distal end of the auxiliary moving cavity 3 is provided with an axially arranged deformation zone. A pulling wire drive mechanism 10 is connected to the catheter base for driving the axial movement of the pulling wire 7. The distal end of the pulling wire 7 is connected to the deformation zone of the auxiliary moving cavity 3.

[0082] This invention optimizes the structure of the microcatheter by axially arranging the first and second channels, effectively reducing the overall outer diameter. Multi-angle composite adjustment is achieved through the combination of an axially arranged deformation zone, an auxiliary moving cavity, and a steering guide sidewall on the side cavity.

[0083] In this application, the end closer to the doctor is called the proximal end, and the end farther from the doctor is called the distal end.

[0084] In this application, the distal outlet refers to the distal end of the auxiliary moving cavity 3.

[0085] The drawing wire 7 is fixedly disposed inside or outside the auxiliary moving cavity. Preferably, the drawing wire 7 is fixedly disposed inside the auxiliary moving cavity.

[0086] The steering guide sidewall is positioned inward from the outlet end, away from the fixed cavity. The catheter base has an outer diameter increasing zone. The outer diameter increasing zone is located between the first channel 1 and the second channel 2. The outer diameter of the outer diameter increases from the first channel 1 to the second channel 2. The angle between the steering guide sidewall and the axial direction of the catheter base is greater than 90° and less than 120°.

[0087] The axially arranged deformation zones are a first deformation zone 31, a second deformation zone 32, and a third deformation zone 33, arranged from the distal end to the proximal end. The stiffness of the first deformation zone 31, the second deformation zone 32, and the third deformation zone 33 increases progressively. Furthermore, the stiffness of the first deformation zone 31 is higher than the stiffness of the remaining areas on the auxiliary moving cavity excluding the first deformation zone 31, the second deformation zone 32, and the third deformation zone 33. The axial lengths of the first deformation zone 31, the second deformation zone 32, and the third deformation zone 33 increase progressively. A single traction wire can be provided, connected to the third deformation zone 33. Alternatively, three traction wires can be provided, each connected to the first deformation zone 31, the second deformation zone 32, and the third deformation zone 33, respectively. This invention achieves multi-angle composite adjustment through the combination of axially arranged deformation zones, an auxiliary moving cavity, and a steering guide sidewall on the side cavity. When the traction drive mechanism 10 drives the auxiliary moving cavity 3 to move axially, the first deformation zone 31, the second deformation zone 32 and the third deformation zone 33 extend out of the side cavity 21 in sequence. When different deformation zones come into contact with the steering guide sidewall, the different stiffness of the different deformation zones will lead to different steering angles, thereby achieving the requirements of different guide wire exit angles.

[0088] For details of the deformation process, please refer to Figures 2 to 4 :

[0089] See Figure 2 Small displacement input: The drawn wire is pushed slightly to overcome the resistance of the first deformation zone with the lowest stiffness, so that it bends alone (about 30°).

[0090] See Figure 3 Displacement input: As the displacement increases, after the first deformation zone bends to its limit, the thrust is transferred to the second deformation zone, causing it to bend superimposed (total angle of about 80°).

[0091] See Figure 4 Large displacement input: As the displacement continues to increase, it eventually triggers the bending of the deformation zone with the highest stiffness, achieving maximum angle adjustment (up to 150°), and can form a composite spatial angle.

[0092] The inner diameter of the first channel 1 is 0.041 mm. It can accommodate a 0.014-inch guidewire. The entire lumen is designed as a single-lumen straight line, with a distal outer diameter of up to 2.3 Fr, significantly lower than that of traditional double-lumen catheters (2.7 Fr). The surface is coated with a hydrophilic coating (polyvinylpyrrolidone, coefficient of friction ≤0.05);

[0093] A serrated guide groove 22 is provided on the steering guide sidewall; the distal sidewall of the auxiliary moving cavity 3 is provided with a serrated structure that meshes with the serrated guide groove 22. Through the meshing of the serrated guide groove 22 and the serrated structure, the anti-torsion and guidance of the auxiliary moving cavity 3 are achieved. The depth of the serrated guide groove 22 is 0.05 mm.

[0094] The auxiliary moving cavity 3 includes an inner layer, a nickel-titanium alloy braided layer, and an outer covering layer arranged sequentially from the inside out. The braiding density of the nickel-titanium alloy braided layer in the first deformation zone 31, the second deformation zone 32, and the third deformation zone 33 increases progressively. The first deformation zone 31 is also provided with a first polymer layer covering the outer covering layer; the second deformation zone 32 is also provided with a second polymer layer covering the outer covering layer; and the third deformation zone 33 is also provided with a third polymer layer covering the outer covering layer. The hardness of the first, second, and third polymer layers increases progressively. The progressive increase in braiding density achieves a progressive increase in the stiffness of the first, second, and third deformation zones. Simultaneously, the progressive increase in the hardness of the polymer layers outside the first, second, and third deformation zones further differentiates the stiffness. The braiding density and the arrangement of the polymer layers facilitate the adjustment of the stiffness of different deformation zones.

[0095] The outer coating is made of polyether block amide with a hardness of 72D. The inner layer is made of polytetrafluoroethylene. The nickel-titanium alloy braided layer is made of nickel-titanium wire with a diameter of 0.02mm.

[0096] The axial length of the first deformation zone is 1-3 mm, the axial length of the second deformation zone is 3-5 mm, and the axial length of the third deformation zone is 5-10 mm. Preferably, the axial length of the first deformation zone 31 is 2 mm, the axial length of the second deformation zone 32 is 3 mm, and the axial length of the third deformation zone 33 is 5 mm.

[0097] The first polymer layer is PEBAX with a hardness of 35D-45D; the second polymer layer is PEBAX with a hardness of 45-55D; and the third polymer layer is PEBAX with a hardness of 55D-75D. Preferably, the first polymer layer is PEBAX with a hardness of 35D; the second polymer layer is PEBAX with a hardness of 55D; and the third polymer layer is PEBAX with a hardness of 75D. PEBAX is a thermoplastic polyetheramide elastomer.

[0098] The braiding density of the titanium alloy braided layer in the first deformation zone 31 is 100-150 pieces / inch; the braiding density of the titanium alloy braided layer in the second deformation zone 32 is 150-210 pieces / inch; and the braiding density of the titanium alloy braided layer in the third deformation zone 33 is 210-250 pieces / inch.

[0099] The wire drawing drive mechanism 10 includes a housing 101 and a ratchet locking mechanism installed within the housing 101. The ratchet locking mechanism includes a ratchet 103, a locking block 104, a spring 105, and a limiting block 106. The ratchet 103 is rotatably mounted within the housing 101, and a drive member 102 for rotating the ratchet 103 is installed outside the housing 101. The ratchet 103 is coaxially connected to a winding shaft, and one end of the drawing wire 7 is wound around the winding shaft. The spring 105 is clamped between the locking block 104 and the limiting block 106. A sliding groove for sliding the locking block 104 is installed within the housing 101. The locking block has toothed protrusions for unidirectionally limiting the ratchet 103. The ratchet has limiting claws arranged circumferentially, and the limiting claws have guide surfaces whose radial length increases circumferentially and radially extending check surfaces. The toothed protrusions are used to limit the ratchet between adjacent limiting claws. The toothed protrusion has an inclined surface that slides in connection with the guide surface. Rotating the drive member 102 clockwise causes the ratchet 103 to rotate clockwise, which in turn causes the drawing wire to be released from the feed wheel and pushed forward by the drawing wire 7 into the auxiliary moving cavity 3. Because the limiting claws have a check surface, when the toothed protrusion is located between the two limiting claws, the drive member can only rotate clockwise; the toothed protrusion will prevent the drive member from rotating counterclockwise.

[0100] The wire drawing drive mechanism 10 also includes a reset mechanism 8, which drives the limit block 106 away from the ratchet 103. The drive component 102 can be a handwheel with an eccentrically mounted rocker arm. This allows the rotation angle of the ratchet 103 to be determined by the position of the rocker arm, thereby determining the axial pushing distance of the auxiliary moving cavity 3. For example, rotating the ratchet by one engagement tooth allows the wire to be delivered forward by 1 mm. A dial is provided on the housing. A reference line for aligning the dial is provided on the handwheel. When the reference line is aligned with the starting end of the dial's scale, the handwheel has moved to its initial position. When the reference line is aligned with the ending end of the dial's scale, the handwheel has moved to the limit position of the auxiliary moving cavity 3's push. The reset mechanism 8 includes an unlocking block 81, which is connected to the housing 101 via a reset spring 82. The unlocking block 81 has an inclined guide rail that slopes from the outside inwards towards the ratchet 103. The unlocking block 81 is slidably connected to the limiting block 106 via the inclined guide rail. A sliding groove for the limiting block 106 is provided inside the housing 101. When the unlocking block 81 is pressed, it causes the limiting block 106 to move away from the ratchet 103. When the unlocking block 81 is released, it causes the limiting block 106 to move towards the ratchet 103. Rotating the drive member 102 clockwise causes the ratchet 103 to rotate clockwise, pushing the auxiliary moving cavity 3 forward via the pull wire 7. The ratchet 103 moves with the locking block, locking in the opposite direction. When the ratchet 103 needs to move in the opposite direction, the limiting block 106 moves away from the ratchet 103 by pressing down on the unlocking block 81. Pull back the spring 105 and the locking block. At this time, the drive component 102 can be rotated clockwise to complete the auxiliary moving cavity 3 to return to the initial position.

[0101] See Figure 10 Two sets of guide mechanisms 11 can be installed at the lead-out end of the winding shaft. Each set of guide mechanisms 11 includes two adjacent guide wheels. The central axes of the guide wheels in the same guide mechanism are parallel to each other, and the central axes of the guide wheels in the two sets of guide mechanisms 11 are perpendicular to each other and both perpendicular to the axial direction of the drawing wire. The drawing wire passes through the gap between the two guide wheels of the two sets of guide mechanisms, thereby guiding the direction of the drawing wire push through the guide wheels.

[0102] The diameter of the drawn wire 7 is 0.1mm, and the material is 304 stainless steel.

[0103] A first imaging ring 4 is provided on the outer wall of the first channel 1; a second imaging ring 5 is provided on the outer wall of the axial guide cavity adjacent to the side cavity 21; and a third imaging ring 6 is provided on the outer wall of the distal end of the auxiliary moving cavity 3. The above imaging rings facilitate the positioning of the catheter.

[0104] The distal end of the second guidewire features a helical segment, 40-50 cm in length, with a helical diameter of 0.4-0.6 mm and a pitch of 0.02-0.08 mm. Traditional guidewire helical segments are typically ≤260 mm long. Extending the helical segment increases the contact area between the guidewire and the vessel wall, improving its stability in acute-angled branches. The contact area between the helical segment and the vessel wall is increased to approximately 2.3 times that of traditional guidewires, ensuring that the catheter is less prone to kinking during retraction.

[0105] The procedure for using this device is as follows:

[0106] Catheter insertion: The first guidewire is passed through the first channel 1, and then the catheter base is pushed along the first guidewire to the bifurcation position and positioned by the first imaging ring 4;

[0107] Angle adjustment: The ratchet 103 is rotated by the drive component 102, and the pull wire 7 drives the auxiliary moving cavity 3 to move axially, causing deformation at the distal end of the auxiliary moving cavity 3, thereby adjusting the outlet direction of the second guide wire in real time; the front and rear displacement of the auxiliary cavity is controlled by the drive component 102, dynamically changing the angle direction of the auxiliary moving cavity extending out of the second channel, thereby adjusting the direction of the second guide wire extending out of the auxiliary channel (adjustment range: 30°-150°).

[0108] The wire drawing drive mechanism causes the axial displacement of the auxiliary moving cavity 3 to change gradually. The greater the axial displacement of the auxiliary moving cavity 3, the greater the bending angle of the auxiliary moving cavity 3.

[0109] The combination of the second developing ring 5 and the third developing ring 6 facilitates determining the position of the auxiliary moving cavity 3 extending out of the second channel. The difference in the relative tilt angles of the second and third developing rings facilitates determining the rotation of the distal end of the auxiliary moving cavity.

[0110] Specifically, small displacement input: the drawn wire is pushed slightly to overcome the resistance of the first deformation zone with the lowest stiffness, causing it to bend alone (about 30°).

[0111] As the displacement increases, the first deformation zone bends to its limit, and the thrust is transferred to the second deformation zone, causing it to bend in combination (total angle of about 80°).

[0112] As the displacement continues to increase, it eventually triggers bending in the deformation zone with the highest stiffness, achieving maximum angle adjustment (up to 150°) and forming a composite spatial angle.

[0113] Guidewire crossing: After the auxiliary moving chamber 3 is adjusted to the appropriate angle, the second guidewire is sent into the branch through the second guidewire channel of the auxiliary moving chamber 3, and is stably advanced by utilizing the friction between the helical segment and the blood vessel wall.

[0114] Catheter retraction: When withdrawing the catheter, the long spiral section can resist guidewire displacement caused by catheter retraction.

[0115] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications 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. A microcatheter with dynamically adjustable distal outlet angle, comprising a catheter base, characterized in that, The catheter matrix has a first channel and a second channel arranged along the axial direction; The first channel is a fixed cavity, serving as a first guidewire channel for guiding the first guidewire through; The second channel includes a side cavity for docking and conducting as well as an axial guide cavity. An auxiliary moving cavity is provided in the second channel to guide the movement of the auxiliary moving cavity. One end of the side cavity is connected to the end of the axial guide cavity adjacent to the fixed cavity, and the other end of the side cavity is the outlet end of the second channel. The inner wall of the side cavity is provided with a sloping steering guide side wall. The auxiliary moving cavity has a second guide wire channel for the second guide wire to pass through, and the distal end of the auxiliary moving cavity is provided with an axially arranged deformation zone. The catheter substrate is connected to a traction wire drive mechanism for driving the traction wire to move axially, and the distal end of the traction wire is connected to the deformation zone of the auxiliary moving cavity.

2. The microcatheter with dynamically adjustable distal outlet angle according to claim 1, characterized in that: The axially arranged deformation zones are a first deformation zone, a second deformation zone, and a third deformation zone arranged axially from the distal end to the proximal end. The stiffness of the first deformation zone, the second deformation zone, and the third deformation zone increases progressively. Furthermore, the stiffness of the first deformation zone is higher than that of the other areas on the auxiliary moving cavity excluding the first deformation zone, the second deformation zone, and the third deformation zone. The axial lengths of the first deformation zone, the second deformation zone, and the third deformation zone increase progressively.

3. The microcatheter with dynamically adjustable distal outlet angle according to claim 2, characterized in that: The auxiliary moving cavity includes an inner layer, a nickel-titanium alloy braided layer, and an outer covering layer arranged sequentially from the inside to the outside. The braiding density of the nickel-titanium alloy braided layer in the first deformation zone, the second deformation zone, and the third deformation zone increases progressively. The first deformation zone is further provided with a first polymer layer covering the outer coating layer; The second deformation zone is further provided with a second polymer layer covering the outer coating layer; The third deformation zone is further provided with a third polymer layer covering the outer coating layer; The hardness of the first polymer layer, the second polymer layer, and the third polymer layer increases progressively.

4. A microcatheter with dynamically adjustable distal outlet angle according to claim 3, characterized in that: The first polymer layer is PEBAX with a hardness of 35D-45D; The second polymer layer is PEBAX with a hardness of 45-55D; The third polymer layer is PEBAX with a hardness of 55D-75D.

5. A microcatheter with dynamically adjustable distal outlet angle according to claim 3, characterized in that: The braiding density of the titanium alloy braided layer in the first deformation zone is 100-150 pieces / inch; The braiding density of the titanium alloy braided layer in the second deformation zone is 150-210 pieces / inch; The braiding density of the titanium alloy braided layer in the third deformation zone is 210-250 pieces / inch; The auxiliary moving cavity has a weaving density of 100-150 pieces / inch in the region behind the third deformation zone.

6. A microcatheter with dynamically adjustable distal outlet angle according to claim 1, characterized in that: The steering guide sidewall is provided with a serrated guide groove; The distal sidewall of the auxiliary moving cavity is provided with a serrated structure that engages with the serrated guide groove.

7. A microcatheter with dynamically adjustable distal outlet angle according to claim 1, characterized in that: The wire drawing drive mechanism includes a housing and a ratchet locking mechanism installed in the housing. The ratchet locking mechanism includes a ratchet, a locking block, a spring, and a limiting block. The ratchet is rotatably mounted inside the housing, and a drive component for rotating the ratchet is mounted outside the housing; The ratchet is coaxially connected to a winding shaft, and one end of the pull wire is wound around the winding shaft. The spring is clamped between the locking block and the limiting block, and the housing is provided with a sliding groove for the locking block to slide. The locking block is provided with toothed protrusions for unidirectionally limiting the ratchet; The wire drawing drive mechanism also includes a reset mechanism, which is used to drive the limiting block away from the ratchet.

8. A microcatheter with dynamically adjustable distal outlet angle according to claim 7, characterized in that: The reset mechanism includes an unlocking block, which is connected to the housing via a reset spring; The unlocking block is provided with an inclined guide rail that is inclined from the outside to the inside towards the ratchet side. The unlocking block is slidably connected to the limiting block through the inclined guide rail. The housing is provided with a sliding groove for the limiting block to slide. When the unlocking block is pressed, the unlocking block causes the limiting block to move away from the ratchet. When the unlocking block is released, it causes the limiting block to move toward the side adjacent to the ratchet.

9. A microcatheter with dynamically adjustable distal outlet angle according to claim 1, characterized in that: A first developing ring is provided on the outer wall of the first channel; A second imaging ring is provided on the outer wall of the axial guide cavity adjacent to the side cavity side; A third developing ring is provided on the outer wall of the distal end of the auxiliary moving cavity.

10. A microcatheter for dynamically adjusting the distal outlet angle according to claim 1, characterized in that: The distal end of the second guidewire is provided with a helical section, the length of which is 40-50cm; The spiral section has a spiral diameter of 0.4-0.6 mm and a pitch of 0.02-0.08 mm.

Images