WO2018121114A1

WO2018121114A1 - Filter for implanting into blood vessel

Info

Publication number: WO2018121114A1
Application number: PCT/CN2017/111120
Authority: WO
Inventors: 张庭超; 李阳; 赵珺
Original assignee: 杭州唯强医疗科技有限公司
Priority date: 2016-12-26
Filing date: 2017-11-15
Publication date: 2018-07-05
Also published as: CN110325148A; CN110062610A; WO2018120414A1; CN207220906U

Abstract

A filter (1000) for implanting into a blood vessel, comprising a central connecting part (1300) and a filter part (1100) and a support part (1200) connected to the central connecting part (1300), the support part (1200) being a plurality of support rods (1210) distributed in a radiating manner, at least some of the support rods (1210) being rolling sections (1212) that bend away from the filter part in a released state, the curvature of the rolling sections (1212) gradually increasing from the side nearest to the central connecting part (1300). By means of changing the shape of the support part (1200), when released, the end of the present filter for implanting into a blood vessel can be immediately rolled up to prevent puncturing of the tissue.

Description

Filter for implantation in blood vessels

Technical field

The present invention relates to the field of medical devices, and more particularly to a filter for implantation into a blood vessel.

Background technique

Pulmonary embolism (PE) is a common health problem and is the leading cause of death in all age groups. Most pulmonary embolisms are caused by deep vein thrombosis (DVT) in the lower extremities or pelvis. Blood clots formed in another part of the body may migrate back to the heart through the veins and into the lungs, causing pulmonary infarction due to loss of blood and oxygen supply to a portion of the lungs. According to statistics, the mortality rate of untreated pulmonary embolism is 20%-30%; the number of newly added cases accounts for 0.2% of the total population every year. According to China's 1.35 billion population, there are about 2.7 million new patients each year.

Filters have been clinically proven to reduce the incidence of pulmonary embolism. In the prior art, the filter structure mainly includes two types, a cage filter of TrapEase structure (such as Cordis TRAPEASE/OPTEASE and Lifetech Aegisy) and a support filter of Kimray-Greenfield structure (such as Boston Scientific Greenfield, St. Jude Amplatz, Bard Denali, COOK Celect and Rex Medical Option).

The filter of the TrapEase structure, such as the publications of the publications CN2710575Y, CN105213065A, CN204909721U, CN2569700Y and CN104970900 A, has the disadvantage that the device increases the area of the struts that the instrument contacts the vessel wall in order to enhance the fixation effect in the inferior vena cava. However, this tends to cause the endothelium to climb the struts. It is easy to tear the endothelium during the process of recovering the instrument and damage the blood vessel wall, and even cause the device to be unrecyclable.

The filter of the Kimray-Greenfield structure, such as the patent documents disclosed in CN104825247A, CN101031254A, CN101143114A, has the disadvantage that when the device is implanted In the inferior vena cava, due to the poor self-centering ability of the conical instrument, the instrument is easy to tilt after implantation into the inferior vena cava. After the instrument is tilted, the recovery head is closely attached to the vessel wall; during the recovery process, the recovery device cannot smoothly capture the recovery head. , will increase the surgical operation time of the device recovery, and even lead to the failure of the device recycling operation.

The general structural feature of the prior art filter has a central connecting portion, and a cage-type or strut-type filtering portion extends from one side of the central connecting portion, and in some filters, a rod-shaped connecting body is connected to the central connecting portion. The support portion and the support portion are turned back toward the filter portion, but the end of the support portion is easily penetrated into the tissue too deep during the release process, thereby posing a safety hazard and affecting the normal release operation.

Summary of the invention

The present invention provides a filter for implantation into a blood vessel, by which the shape of the support portion is improved, and the end of the support can be rolled up in time to avoid stabbing the tissue.

A filter for implantation into a blood vessel, comprising a central connection portion and a filter portion and a support portion connected to the central connection portion, wherein the support portion is a plurality of struts of radiation distribution, at least a portion of the struts being released The lower curved turn section has a gradually increasing curvature from the side adjacent the center joint.

In the present invention, the curvature of the rolled section is gradually increased as an overall trend, and the curve which must be a gradual change is not strictly limited, or may be a combination of a plurality of straight segments, or a combination of a straight line and a curved line, due to the overall The upper curvature gradually increases, and the trend toward the end of the roll is more obvious.

Two types of solutions are provided in the present invention for the direction of the roll of the pole. Optionally, the rollover method of the roll section is:

In the mode A, the central connecting portion first extends toward the side of the filtering portion and is turned back toward the filtering portion; or

In the mode B, the central connecting portion first extends away from the side of the filter portion and is rolled toward the filter portion.

The struts are extended from the central connecting portion to the side of the filtering portion. The overall extension trend should be understood as extending in the axial direction, and also allowing a certain angle, that is, the extension has just begun. Rolling, the same reason to extend away from the side of the support, is also understood as the overall trend.

The end of the strut is a free end of the suspension. When the support end is extended to the side of the support portion, the end is first released, and when it is extended toward the side away from the support portion, it is released after the end.

The struts on the same filter can also be rolled in different ways. Optionally, the struts are divided into two groups, and the tumbling segments are respectively rolled according to mode A and mode B;

In the mode A, the central connecting portion first extends toward the side of the filtering portion and is turned back toward the filtering portion;

In the mode A, the struts are turned back toward the filter part, so that when released in the body, the first released end is rolled up to a certain angle when reaching the inner wall of the blood vessel, and the end of the end is directly contacted with the inner wall of the blood vessel, thereby further eliminating the safety hazard.

In the mode B, the struts are rolled toward the filter portion. According to the structure, it can be seen that the recovery problem of the filter is no longer considered, but it is desirable to form a permanent support in the blood vessel to meet the needs of some patients. The description of the shape of the present invention is understood to mean the release of the unfolded shape in vivo, unless otherwise stated.

Preferably, the rolled section is a smooth curve whose curvature changes continuously or intermittently.

The scrolling section can adopt a smooth curve. For the curve itself, the curvature can be continuously changed, or a certain middle section can be kept unchanged, and then become smaller, that is, intermittently changed, but in any case, the overall trend of the rolled section is The tendency to roll around the end is more obvious and should not be limited to local variations in a small size range.

Optionally, the starting point of the rolled section is connected to the central connecting portion through a first straight line segment or directly connected to the central connecting portion.

One end of the scrolling section adjacent to the central connecting portion can be regarded as a starting point. In order to better connect with the central connecting portion, the first straight line segment can be connected to the central connecting portion, and the first straight straight section can be regarded as a transitional connection with the central connecting portion. In order to start rolling from a suitable axial position.

Preferably, a cross-linking junction adjacent to the central connecting portion is provided between the adjacent struts in the circumferential direction. Structure.

Since the filter is in a compressed state before being released, the crosslinked structure is a deformable structure, for example, two adjacent struts are formed into a parallelogram or the like by a crosslinked structure at the cross-linking.

The crosslinked structure can further increase the stability of the support portion, and in order to avoid interference with the roll, the crosslinked structure is only increased at a position close to the center joint portion. At the same time, the cross-linked structure can filter out some small thrombus.

Preferably, the end of the turning section is provided with an anchor thorn, which is anchored in the same direction as the turning section. Support and positioning can be further enhanced by setting the anchor.

Optionally, the end point of the turning section is the end of the pole, or the second straight section is connected at the end point. The second straight line segment should not be too long, only as an extension and auxiliary stabilization of the rolled section.

In order to ensure an overall rolling effect and tendency, the rolled section should have a sufficient length in the struts in which it is located, preferably the length of the rolled section is at least 1/2 of the total length of the struts.

Further preferably, the length of the rolled section is at least 2/3 of the total length of the strut until the struts are integrally turned as a rolled section.

When the rolled section is not a continuous curve, it can be regarded as being formed by sequentially connecting a plurality of segments, and the bending points of the adjacent segments are changed to achieve a change in the overall curvature.

Preferably, the rolled section is divided into at least three sub-sections, and the connecting portion of the adjacent sub-section is an inflection point with a sudden change of curvature, and one end of the rolled-back section is a starting point and is directly connected to the central connecting portion, and the other end is an end point and directly extends to the branch. The end of the rod; the starting point, the end point and all the inflection points, the arc determined between the adjacent three points is the reference arc, and the curvature of each reference arc from the starting point to the end point increases in turn.

Since there is an inflection point with a sudden change of curvature between adjacent segments, and a segment may also be a straight line segment, it may be difficult to consider its curvature in its local part. Since the present invention focuses on the improvement of the overall rolling tendency, the present scheme The concept of a reference arc is introduced to evaluate the curvature change trend of the roll.

Optionally, different sub-segments are independent of straight segments or curved segments.

Preferably, all sub-segments are straight segments.

In order to minimize the stab wound of the blood vessel at the end of the struts, there should be a small radius of curvature at the end of the tumbling section. Preferably, the radius of curvature of the end portion of the tumbling section is 0.5 to 5 mm.

As far as the struts are concerned, the angle of rollover should not be too small, otherwise the degree of tumbling at the end of the struts is insufficient to avoid penetration into the blood vessel. Preferably, the lap angle of the struts is greater than 180 degrees.

The angle of the roll can be referred to the direction of the end of the rod. For example, the end of the rod in the mode A is directed to the filter portion, which is 180 degrees. If it is greater than 180 degrees, the roll should be continued. If the roll is 360, the end of the rod points to the filter. Part B is the same.

In order to optimize the relationship between the degree of curling of the end of the strut and the distance of the inner wall of the blood vessel during the release process, preferably, the shape of the strut satisfies: D2 < D1 < D;

D: the maximum width spanned by the strut relative to the first boundary line with the central connecting portion axis as the first boundary line;

D1: the tangential line at the end of the strut is the second boundary line, and the maximum width spanned by the strut relative to the second boundary line;

D2: taking the end of the strut as the intersection point, the perpendicular line passing through the second boundary line of the intersection point is the dividing line, and the maximum distance spanned by the strut on the side of the dividing line facing away from the central connecting portion.

The optimization of D1 ensures that the end of the rod is curled before it is released, and the roll angle is 180°. However, only D1 is defined, and there is still another risk that the end of the struts penetrates into the blood vessel during the release, so this problem is overcome by the preference of D2.

The maximum diameter of the blood vessel is 2D (16 to 34 mm interval, usually 24 mm), and in view of the usual size of the blood vessel, D1 < 17 mm and D2 < 8 mm are preferable.

As far as the filter portion itself is concerned, various forms of the prior art can be employed, such as a single-layer strut structure or a cage structure.

In order to increase the strength of the support portion, preferably, each of the support rods is near the center The area of the joint has a cross-linked structure, and the maximum diameter of the cross-linking position does not exceed 30 mm. The cross-linked structure is a network structure, which can further enhance the support force and stability of each strut.

The filter part and the support part may be formed by cutting the pipe material, or may be directly shaped by the wire material; the material may be made of stainless steel having a shape memory function, a nickel-titanium alloy, a cobalt-chromium alloy or a titanium alloy, etc. One or more components.

The support portion of the filter of the invention has uniform and higher radial support force, so that the device has better self-centering performance, prevents the instrument from tilting, and reduces the endothelial climbing, which is beneficial to the device for capturing and recycling and prolonging the recovery time. Through the optimization of the shape of the struts, the risk of piercing the blood vessels during release is avoided, and the plurality of struts not only play an anchoring role, but also prevent the instrument from being displaced under the scouring of the blood flow, and can also play a filtering role to achieve the double filtering effect of the filter. To improve the effectiveness of the device.

DRAWINGS

1 is a schematic structural view of a filter of Embodiment 1;

Figure 2 is a schematic view of the contact portion of the struts with the blood vessel wall;

Figure 3 is a schematic view of the shape of the strut;

4 is a schematic structural view of a filter of Embodiment 2;

Figure 5 is a schematic view showing the shape of the strut of the third embodiment;

Figure 6 is a schematic view of the anchor thorn at the end of the strut;

Figure 7 is a schematic view showing the shape of the strut of the fourth embodiment;

Figure 8 is a schematic view of the comparative shape of the strut;

9 is a schematic structural view of a filter of Embodiment 5;

Figure 10 is a schematic view showing the structure of the filter of Embodiment 6;

Figure 11 is a schematic view showing the state of use of the filter of the embodiment 7;

[Correct according to Rule 91 24.01.2018]
Figure 12 is a schematic view showing the structure of the filter of Embodiment 7;

[Correct according to Rule 91 24.01.2018]

detailed description

Example 1

Referring to Fig. 1, the filter 1000 of the present embodiment includes a filter portion 1100, a support portion 1200 and a central connecting portion 1300. After being laser-cut by an OD2.0 mm nickel-titanium tube, it is heat-set by a mold.

The filter portion 1100 is configured to capture the plug from the blood flow direction, and includes six filter portion rods 1100 extending outward from the central connecting portion 1300. The filter portion rod 1100 has an angle of about 0 to 90 degrees from the central axis Y, at least two of which The end of the root filter strut 1100 includes a barb 1110, and the filter portion 1100 may be a single-layer strut structure, and may also have a cage structure.

The support portion 1200 is used to prevent the instrument from tilting, and is extended outward from the central connecting portion 1300 and rolled upward toward the filter portion 1100 as a whole in the orientation of the drawing. The support portion 1200 is a plurality of radial struts 1210 having at least three, and in this embodiment, six struts 1210.

When in use, the device of the present embodiment is delivered to the lower part of the renal artery via the jugular vein, and the delivery catheter is withdrawn. The filter filter portion 1100 is gradually released from the catheter, and self-expanding is deployed. The barb 1110 at the end first adheres to the blood vessel and penetrates the blood vessel. The wall is anchored, the delivery catheter is further retracted, the support portion 1200 is unfolded, and the wall is gradually attached. Under the action of the support portion 1200, the filter 1000 is less likely to be inclined, and the central connection portion 1300 is difficult to be attached, so that the device is easier to recycle, and the device is easier to recycle. The filter is mainly in point contact with the blood vessel wall (see FIG. 2), and the tumbling portion of the struts is in contact with the blood vessel wall 2000 near the end, and is non-face contact, which can effectively reduce the endothelial climbing and prolong the filter recovery time.

In the support portion, at least a part of each of the struts is a rolled portion that is bent away from the filter portion in a released state, and the curling portion gradually increases in curvature from a side adjacent to the central connecting portion, and the curvature gradually increases, which is understood as an overall trend, that is, The more obvious the tendency to roll near the end, the example is the strut 1210 in FIG. 3, the point A is the boundary, the straight line segment 1211 is connected to the central connecting portion, and the lower side of the point A is the rolled portion 1212, and the rolled portion 1212 is a smooth curve. The tendency of the curvature to change continuously and gradually increase toward the end is more obvious.

In order to optimize the relationship between the degree of curling of the end of the strut 1210 and the distance of the inner wall of the blood vessel during the release process, the shape of the strut 1210 satisfies: D2 < D1 < D;

D: the maximum width spanned by the strut 1210 with respect to the first boundary line with the central connecting portion axis Y as the first boundary line;

D1: a maximum width spanned by the strut 1210 with respect to the second boundary line with the tangent L1 at the end of the strut 1210 as the second boundary line;

D2: the end point of the strut 1210 is the intersection point B, and the perpendicular line L2 passing through the second boundary line of the intersection point B is the boundary line, and the maximum distance spanned by the strut on the side of the boundary line facing away from the center connecting portion.

Since the tendency to roll near the end is more pronounced, when the strut 1210 is gradually released and attached, the end portion is already curled and does not penetrate the blood vessel wall, thereby avoiding the risk of the support portion damaging the blood vessel. This effect can be further ensured by the relative relationship of D2, D1, and D.

Example 2

Referring to FIG. 4, with respect to Embodiment 1, the difference in this embodiment is that there is a certain cross-linking structure at the position of each strut near the central connecting portion, which can improve the connection between the strut of the supporting portion and improve the radial direction. Supporting force while improving the filtering effect of the device.

The maximum outer diameter D3 of the cross-linked structure should not exceed 24 mm, so as to avoid contact between the position of the cross-section and the vessel wall. After the endothelium is climbed, the filter will be difficult to remove.

Example 3

Referring to FIG. 5, with respect to Embodiment 1, the difference in this embodiment is that the shape of the strut 1210 is different, and the rolled section is divided into four straight sections which are sequentially connected, which are a straight section 1213, a straight section 1214, and a straight section 1215. The straight line segment 1216, the connecting portion of the adjacent segment is the inflection point of the sudden change of curvature, followed by the inflection point G1, the inflection point G2, the inflection point G3, the end of the scrolling section is the starting point G0, and the other end is the ending point G4; as a whole, it is not difficult to see that the end is rolled over. The trend is even more pronounced, and the ever-increasing curvature of the flip-flop can solve the risk of the struts piercing the vessel wall during the release process.

The arc determined between the three points of the starting point G0, the inflection point G1 and the inflection point G2 is the reference arc C1;

The arc determined between the three points of the inflection point G1, the inflection point G2, and the inflection point G3 is a reference arc C2;

The arc determined between the inflection point G2, the inflection point G3, and the end point G4 is the reference arc C3;

It is apparent that the curvatures of the reference arc C1, the reference arc C2, and the reference arc C3 are sequentially increased, that is, the diameters of the three are sequentially smaller. The figure also satisfies D2 < D1 < D.

Referring to Figure 6, the straight section 1216 can also be provided with an anchor 1217 that is in contact with the vessel wall 2000, in contact with the vessel wall 2000 to enhance the positioning effect. One is to prevent the filter from shifting, and the other is to control the depth of the piercing of the blood vessel wall if the struts pierce the blood vessel wall because of the presence of the barbed bifurcation;

Example 4

Referring to FIG. 7, compared with Embodiment 3, the difference of this embodiment is that the shape of the strut 1210 is different, and the rolled section is divided into six straight segments which are sequentially connected, and although the number of straight segments is increased, D2<D1 is also satisfied. <D and the limitation that the curvature of each reference arc increases sequentially.

Referring to Fig. 8, the rolled section is a smooth circular arc, but a straight section 1218 is extended at the end. For comparison, D2>D1 in Fig. 8 is visible according to the shape of the strut in the figure, and the straight section 1218 is too long, and is still at the end of the release period. There is a risk of stabbing blood vessels.

Example 5

Referring to FIG. 9, the filter 1000 of the present embodiment includes a filter portion 1100, a support portion 1200 and a central connecting portion 1300. The main difference from the first embodiment is that the support portion 1200 is formed by using a wire of 0.1 to 0.6 mm. Materials include, but are not limited to, one or more of stainless steel, nickel titanium alloy, cobalt chromium alloy, titanium alloy, and the like. In this embodiment, there are six 0.35mm nickel-titanium wires, one end is sleeved with a steel sleeve, and then connected by argon arc welding, and then heat-shaped by a mold to form a continuous smooth curved support arm.

Example 6

In the prior art, the vena cava filter is generally implanted under the renal artery. This embodiment provides a technical solution for placing the filter, which may be above the renal artery, increasing the anchoring area of the filter, and expanding the use of the filter. range.

Referring to Fig. 10, in the filter 1000 of the present embodiment, the filter portion 1100 is located below the renal artery 2100, and the support portion 1200 is located above the renal artery 2100.

Example 7

Referring to FIG. 11, FIG. 12 is a permanent implant filter. In this embodiment, the strut 1210 is rolled up according to the mode B, that is, the central connecting portion is first extended upward (ie, away from the side of the filter portion), and then rolled downward (ie, toward the filter). The side is rolled up on one side, and the direction of the roll is exactly the opposite of the previous embodiments. The filter can be implanted through the femoral vein, and the support portion is at the distal end. First, the support portion is gradually released, the support rod is bent and deployed, and finally the filter portion is deployed.

As can be seen from its structure, the rewinding of mode B no longer considers the recovery of the filter, but rather the desire to form a permanent support within the blood vessel. The filter rod has a smaller contact area with the blood vessel wall, reduces endothelial climbing, has a lower probability of occlusion of blood vessels, improves the long-term normal rate of blood vessels, and has good self-centering performance to prevent tilting of the instrument.

Further, the support portion in this embodiment may also be provided with an anchor thorn as in Embodiment 3 to prevent the filter from being displaced.

Claims

A filter for implantation into a blood vessel, comprising a central connection portion and a filter portion and a support portion connected to the central connection portion, wherein the support portion is a plurality of struts of radiation distribution, wherein at least the struts are A portion is a rolled section that is bent in a released state, and the curling section gradually increases in curvature from a side adjacent to the center connecting portion.
A filter for implantation into a blood vessel according to claim 1, wherein said scrolling section is rolled in the following manner:

In the mode A, the central connecting portion first extends toward the side of the filtering portion and is turned back toward the filtering portion; or

In the mode B, the central connecting portion first extends away from the side of the filter portion and is rolled toward the filter portion.
The filter for implanting a blood vessel according to claim 1, wherein the struts are divided into two groups, and the tumbling segments of the two sets of struts are rolled in accordance with mode A and mode B, respectively;

In the mode A, the central connecting portion first extends toward the side of the filtering portion and is turned back toward the filtering portion;

In the mode B, the central connecting portion first extends away from the side of the filter portion and is rolled toward the filter portion.
A filter for implantation into a blood vessel according to claim 1, wherein said rolled section is a smooth curve whose curvature changes continuously or intermittently.
A filter for implantation into a blood vessel according to claim 4, wherein the starting point of the rolled section is connected to the central connecting portion by a first straight section or directly connected to the central connecting portion.
The filter for implantation into a blood vessel according to claim 4, wherein the end of the scrolling section is the end of the strut, or the second straight section is connected to the end point.
A filter for implantation into a blood vessel according to claim 4, wherein the length of the rolled section is at least 2/3 of the total length of the strut until the struts are integrally turned as a rolled section.
The filter for implantation into a blood vessel according to claim 4, wherein the radius of curvature of the end portion of the rolled portion is 0.5 to 5 mm.
The filter for implanting a blood vessel according to claim 1, wherein the rolled section is divided into at least three sub-sections, wherein the joint portion of the adjacent sub-section is an inflection point with a sudden change in curvature, and one end of the rolled-up section is a starting point. Directly connected to the central connection, the other end is the end point and extends directly to the end of the pole; in the starting point, the end point and all the inflection points, the arc determined between the adjacent three points is the reference arc, and each reference from the starting point to the end point The curvature of the arc increases in turn.
A filter for implantation into a blood vessel according to claim 9, wherein the different sub-sections are each independently a straight line segment or a curved segment.
A filter for implantation into a blood vessel according to claim 10, wherein all of the sub-sections are straight segments.
A filter for implantation into a blood vessel according to claim 1, wherein the struts have a roll angle greater than 180 degrees.
The filter for implantation into a blood vessel according to claim 1, wherein a cross-linked structure located adjacent to the central connecting portion is provided between the adjacent struts in the circumferential direction.
A filter for implantation into a blood vessel according to claim 1, wherein an end of said rolled section is provided with an anchor spurting anchoring direction which is the same as a turning direction of the rolled section.
The filter for implanting a blood vessel according to any one of claims 1 to 14, wherein the shape of the strut satisfies: D2 < D1 < D;

D: the maximum width spanned by the strut relative to the first boundary line with the central connecting portion axis as the first boundary line;

D1: the tangential line at the end of the strut is the second boundary line, and the maximum width spanned by the strut relative to the second boundary line;

D2: taking the end of the strut as the intersection point, the perpendicular line passing through the second boundary line of the intersection point is the dividing line, and the maximum distance spanned by the strut on the side of the dividing line facing away from the central connecting portion.
A filter for implantation into a blood vessel according to claim 15, wherein D1 < 17 mm and D2 < 8 mm.
A filter for implantation into a blood vessel according to any one of claims 1 to 14, wherein the filter portion includes a filter portion struts extending outward from the central connection portion.