Spiral adaptive aortic dissection stent and design method thereof
By designing a spiral adaptive aortic dissection stent, and utilizing a fiber module structure that combines dense and sparse skeletons, the problems of secondary damage and insufficient coverage in traditional stents within spiral dissections are solved, achieving better intimal patch recovery and biocompatibility.
Patent Information
- Application Number
- CN202511273902.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-08
- Publication Date
- 2025-11-11
AI Technical Summary
Existing thoracic aortic dissection stents are prone to causing secondary damage to the intimal flap when used in a dissecting lumen with helical rotation, and their short length cannot effectively cover the long dissecting tear area, resulting in poor recovery.
A spiral adaptive aortic dissection stent is designed, which adopts a ring-shaped stent body composed of multiple fiber modules. Through a biomimetic connection method, a dense skeleton and a sparse skeleton are combined to adapt to the spiral morphology of aortic dissection. The density and sparseness of the fiber modules are adjusted according to the degree of rotation and length in different regions.
It reduces the incidence of new dissections induced at the stent tip, promotes uniform stress distribution and recovery of the intima patch, reduces the risk of thrombosis, and improves the biocompatibility and therapeutic efficacy of the stent.
Smart Images
Figure CN120918847A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a spiral adaptive aortic dissection stent and its design method, belonging to the field of medical device technology. Background Technology
[0002] Aortic dissection refers to a condition where the aortic wall is damaged due to disease or external stimuli, allowing blood to tear the aortic wall through the tear. This creates two lumens in the aorta, the original lumen being called the true lumen, and the newly formed lumen being called the false lumen. Aortic dissection is a serious cardiovascular disease, attracting significant attention due to its high incidence, high mortality, and low survival rate after intervention.
[0003] Currently, the main treatment for thoracic aortic dissection is the implantation of a stent to cover the primary tear, preventing blood from flowing into the false lumen and thus inhibiting its further expansion. The stents used in surgery to seal the tear are mostly covered stents, which have good support and compliance, effectively blocking blood flow to the tear and preventing further tearing.
[0004] Current research has found that the true lumen of some aortic dissections exhibits a certain spiral characteristic. Within the dissected lumen (true lumen) with strong spiral rotation, repairing the tear with traditional straight stents or covered stents with a certain taper can easily lead to secondary damage to the intimal flap. Prolonged exposure to pulsating blood flow can also induce new tears, leading to dissection progression or rupture, and even causing serious complications such as death. Furthermore, existing stents are relatively short, only covering the area near the tear; for longer dissections, the recovery effect is poor, indicating areas for improvement. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a spiral adaptive aortic dissection stent and its design method, which can better adapt to the spiral morphology of the true lumen of aortic dissection and reduce the formation of new dissection ruptures induced at the stent tip.
[0006] To achieve the above-mentioned technical objectives and effects, this application provides the following technical solution:
[0007] In a first aspect, the present invention provides a spiral adaptive aortic dissection stent, comprising a ring-shaped stent body composed of multiple sets of fiber modules, wherein adjacent sets of fiber modules are connected in a biomimetic manner, and a biodegradable polymer or composite material is used for smooth transition. Each set of fiber modules is composed of two skeletons connected together, namely a dense skeleton and a sparse skeleton, wherein the dense skeleton corresponds to the false lumen ratio range, and the sparse skeleton corresponds to the true lumen ratio range.
[0008] Preferably, the skeleton at the connection between two adjacent groups of fiber modules is densely arranged, and the sparse support of the sparse skeleton is replaced with a dense support.
[0009] Preferably, the support body includes a strong helical support, wherein the dense and sparse skeletons of the strong helical support undergo helical rotation.
[0010] Preferably, the support body includes a weak spiral support, wherein the dense and sparse skeletons of the weak spiral support do not rotate and are arranged in a straight line.
[0011] Preferably, the scaffold body is a biodegradable material scaffold.
[0012] Secondly, the present invention provides a design method for a spiral adaptive aortic dissection stent, wherein the spiral adaptive aortic dissection stent is the aforementioned spiral adaptive aortic dissection stent, and the design method includes the following steps:
[0013] Based on the landmark anatomical locations and the major vascular branches of the abdominal aorta, aortic dissection is divided into zones;
[0014] The stent fiber module design determines the period and number of the dense and sparse skeletons in each aortic dissection region;
[0015] Assemble the support body.
[0016] Preferably, the step of dividing the aortic dissection into zones includes the following steps:
[0017] Six characteristic horizontal sections are selected, denoted as S. i (i = 0, 1, ..., 5), plane S0 is located 2 cm below the apex of the lesser curve of the aortic arch to avoid the curved part of the aorta; plane S1 is located at the level of the aortic sinus; plane S2 is defined as the level of the apex of the diaphragm in human anatomy; plane S3 is the level above the opening of the celiac trunk; plane S4 is the level below the opening of the inferior renal artery; plane S5 is the level at the bifurcation of the abdominal aorta.
[0018] Six characteristic horizontal sections divide the aorta into five aortic regions, denoted as C. i (i = 1, 2, ..., 5), where region C i Between plane S i-1 and plane S i Between these regions, the five aortic regions are named the proximal descending thoracic aorta region, the mid-descending thoracic aorta region, the distal descending thoracic aorta region, the visceral vessel region, and the abdominal aorta region. The length of the axis of each region is measured and denoted as h. i (i = 1, 2, ..., 5);
[0019] The true cavity helix angle, true cavity initiation angle, and true cavity termination angle are measured for each characteristic horizontal section and denoted as α. i , and The true cavity percentage of each region is defined as the difference between the true cavity termination angle at the bottom of the region and the true cavity initiation angle at the top of the region, denoted as Then there is The proportion of false cavity is recorded as Then there is Measure the maximum diameter of each characteristic horizontal section, and record it as follows:
[0020] Furthermore, determining the period and number of the dense and sparse skeletons in each aortic dissection region includes the following steps:
[0021] The radius of a single fiber module is r, and the height is d. The fiber radius is 5% to 10% of the normal aortic diameter in that region. The length of one cycle of the dense skeleton is denoted as l. dense The length of one period of the sparse skeleton is denoted as l. sparse The length of a single period in a sparse skeleton is twice the length of a single period in a dense skeleton, i.e., l sparse =2l dense ;
[0022] Generally, the length of one cycle in a dense skeleton is 1 / 12 of the scaffold circumference, and the length of one cycle in a sparse skeleton is 1 / 6 of the scaffold circumference.
[0023]
[0024] The number of periods for the dense and sparse skeletons in each region are denoted as follows: and The number of periods in the sparse skeleton is calculated based on the proportion of true cavities, i.e.:
[0025] Where [] denotes the floor function, and the number of dense skeleton periods is
[0026] Furthermore, the assembly of the support body includes the following steps:
[0027] The assembly of the support body includes the following steps:
[0028] A contrast ring is marked at the top of each fiber module, and a feature point is marked on the contrast ring. The marked point is located at the intersection of the sparse skeleton and the axis of symmetry of the stent body in each aortic dissection region, and the angle formed by the mark and the horizontal direction is denoted as . When implanting the stent body, ensure that the marked position of each region is located on the axis of symmetry of the true cavity, that is: The number of fiber module pairs in each region is denoted as n. i (i = 1, 2, ..., 5), calculate the number of fiber module pairs for each region based on the height of the region axis and the height of a single group of fiber modules, then:
[0029] Combining the number of cycles of the sparse and dense skeletons of each region's fiber module, and (i = 1, 2, ..., 5), assemble the support frame.
[0030] Furthermore, the radius of the stent body in each aortic dissection region is denoted as r. i (i=1,2,...,5), which is 5% to 10% larger than the average diameter of blood vessels in the region, and the assembled stent body is tapered as a whole.
[0031] The present invention provides a spiral adaptive aortic dissection stent and its design method, which have the following advantages:
[0032] 1. The spiral-adaptive aortic dissection stent of the present invention, through the implantation of a novel spiral-adaptive stent, adjusts the density of the stent skeleton according to different support sites to achieve different effects. The portion supporting the vascular wall uses a sparse skeleton to reduce contact between the stent and the vascular wall, preventing blockage of visceral vessels and thus reducing the risk of thrombosis and other complications. The portion supporting the intima uses a dense skeleton, making the stress and displacement on the intima more uniform, thereby better promoting the expansion of the true lumen of the dissection, thrombosis of the false lumen, and better remodeling of the intima.
[0033] 2. The spiral adaptive aortic dissection stent of the present invention proposes a spiral adaptive stent based on the spiral characteristics of aortic dissection; for the thinner and weaker intimal flap, the stent body dimensions are densified to make the stress and displacement of the intimal flap more uniform, which can better help the intimal flap recovery and prevent secondary damage to the intimal flap during the recovery process; for the thicker and relatively stronger vascular endothelium, although the sparse skeleton has a less uniform effect on the vascular endothelium than the dense skeleton stent and will generate greater stress and displacement, it can support the vascular endothelium to ensure the normal operation of the stent.
[0034] 3. The spiral adaptive aortic dissection stent of the present invention has different degrees of rotation and lengths in different regions of the aorta. To accommodate different degrees of rotation and region lengths, the number of dense and sparse skeletons in each group of fiber modules and the rotation angle between the fiber modules are modified to adapt to different dissection conditions. Except for the connection positions, the fiber structure of the stent body is identical between each group of fiber modules, thus achieving a modular design of the stent.
[0035] 4. In terms of solubility, the spiral adaptive aortic dissection stent of the present invention has a volume that is reduced by about 10.1% compared to the volume of a dense stent, and therefore is more easily absorbed by human blood and has better biocompatibility. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of the structure of the fiber module provided in an embodiment of the present invention;
[0037] Figure 2 This is a schematic diagram of the deployed state of a spiral adaptive aortic dissection stent provided in an embodiment of the present invention;
[0038] Figure 3 A schematic diagram of the optimized connection design between two adjacent fiber modules provided in an embodiment of the present invention. Figure 1 ;
[0039] Figure 4 A schematic diagram of the optimized connection design between two adjacent fiber modules provided in an embodiment of the present invention. Figure 2 ;
[0040] Figure 5 This is a schematic diagram of the unfolded state structure of the support body provided in an embodiment of the present invention when it is a strong helical support;
[0041] Figure 6 This is a schematic diagram of the unfolded state structure of the support body provided in an embodiment of the present invention when it is a weak spiral support.
[0042] Figure 7 A schematic diagram of aortic dissection partitions provided by an embodiment of the present invention for a design method of a spiral adaptive aortic dissection stent;
[0043] Figure 8 This is a cross-sectional schematic diagram of each zone of the aortic dissection, provided as an embodiment of the present invention, for designing a spiral adaptive aortic dissection stent.
[0044] In the picture:
[0045] 1-Scaffold body; 11-Fiber module; 111-Dense skeleton; 112-Sparse skeleton. Detailed Implementation
[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0047] Reference Figure 1 and Figure 2 A spiral adaptive aortic dissection stent includes an annular stent body 1 composed of multiple sets of fiber modules 11. The stent body 1 is made entirely of biodegradable materials, such as aluminum alloy or polyester fiber, so that the stent degrades after two to three years. While helping the aortic dissection to recover, it reduces the rejection reaction of the blood vessel and prevents stent-induced complications or secondary damage.
[0048] Adjacent fiber modules 11 are connected in a biomimetic manner, using biodegradable polymers or composite materials for a smooth transition. These materials can be absorbed by the blood along with the stent body 1, such as dopamine-based biomimetic adhesives. Each fiber module 11 consists of two connected skeletons: a dense skeleton 111 and a sparse skeleton 112. The dense skeleton 111 corresponds to the pseudo-lumen ratio range, and the sparse skeleton 112 corresponds to the true lumen ratio range.
[0049] Reference Figure 3 and Figure 4 At the connection of each region, in order to prevent large deformation caused by large holes in the support body 1, the skeleton at the connection of two adjacent fiber modules 11 is densified, and the sparse support of the sparse skeleton 112 is replaced with a dense support.
[0050] Reference Figure 5 The main body of the stent includes a strong helical stent, in which the dense skeleton 111 and the sparse skeleton 112 of the strong helical stent rotate in a helical manner.
[0051] Reference Figure 6 The main body of the support also includes a weak spiral support. The dense skeleton 111 and sparse skeleton 112 of the weak spiral support do not rotate and are arranged in a straight line.
[0052] The working principle of the spiral adaptive aortic dissection stent provided by this invention is as follows:
[0053] During endovascular repair of thoracic aortic dissection (TEVAR), the appropriate stent type is selected based on the spiral characteristics of the true lumen of the aortic dissection. Strong spiral stents are selected for strong spiral dissections, and weak spiral stents for weak spiral dissections. If the true lumen rotation is significant, a strong spiral stent is selected based on the degree of torsion. The dense framework 111 and sparse framework 112 of the strong spiral stent exhibit spiral rotation, with the dense framework 111 supporting the intimal flap and the sparse framework 112 supporting the inner wall of the vessel's true lumen, thus better promoting aortic remodeling processes such as true lumen expansion and false lumen thrombosis in aortic dissection patients. If the true lumen rotation is not significant, a weak spiral stent is selected. The dense framework 111 and sparse framework 112 of the weak spiral stent do not rotate and are arranged in a straight line.
[0054] The present invention provides a design method for a spiral adaptive aortic dissection stent, comprising the following steps:
[0055] S1, refer to Figure 7 and Figure 8 Based on the landmark anatomical locations and the main vascular branches of the abdominal aorta, the aortic dissection is divided into zones;
[0056] Specifically, the process of dividing aortic dissection into zones includes the following steps:
[0057] Six characteristic horizontal sections are selected, denoted as S. i (i = 0, 1, ..., 5), plane S0 is located 2 cm below the apex of the lesser curve of the aortic arch to avoid the curved part of the aorta; plane S1 is located at the level of the aortic sinus; plane S2 is defined as the level of the apex of the diaphragm in human anatomy; plane S3 is the level above the opening of the celiac trunk; plane S4 is the level below the opening of the inferior renal artery; plane S5 is the level at the bifurcation of the abdominal aorta.
[0058] Six characteristic horizontal sections divide the aorta into five aortic regions, denoted as C. i (i = 1, 2, ..., 5), where region C i Between plane S i-1 and plane S i Between these regions, the five aortic regions are named the proximal descending thoracic aorta region, the mid-descending thoracic aorta region, the distal descending thoracic aorta region, the visceral vessel region, and the abdominal aorta region. The length of the axis of each region is measured and denoted as h. i (i = 1, 2, ..., 5);
[0059] The true cavity helix angle, true cavity initiation angle, and true cavity termination angle are measured for each characteristic horizontal section and denoted as α. i , and The true cavity percentage of each region is defined as the difference between the true cavity termination angle at the bottom of the region and the true cavity initiation angle at the top of the region, denoted as Then there is The proportion of false cavity is recorded as Then there is Measure the maximum diameter of each characteristic horizontal section, and record it as follows:
[0060] S2, stent fiber module 11 design, determining the period and number of dense skeletons 111 and sparse skeletons 112 in each aortic dissection region;
[0061] Specifically, determining the period and number of dense skeletons 111 and sparse skeletons 112 in each aortic dissection region includes the following steps:
[0062] Design as Figure 1 The stent shown has a single fiber module 11 structure with radius r and height d. The fiber radius is 5% to 10% of the normal aortic diameter in this region. The length of one cycle of the dense skeleton 111 is denoted as l. dense The length of one period of the sparse skeleton 112 is denoted as l. sparse The length of a single period in the sparse skeleton 112 is twice the length of a single period in the dense skeleton 111, i.e., l sparse =2l dense ;
[0063] Generally, the length of one cycle of the dense skeleton 111 is 1 / 12 of the scaffold circumference, and the length of one cycle of the sparse skeleton 112 is 1 / 6 of the scaffold circumference, that is:
[0064]
[0065] The number of periods for the dense skeleton 111 and the sparse skeleton 112 in each region are denoted as follows: and The number of periods in the sparse skeleton 112 is calculated based on the proportion of true cavities, i.e.:
[0066] Where [ ] represents the floor function, and the number of periods in the dense skeleton 111 is
[0067] Generally, the sparse skeleton 112 has 2 or 3 periods, while the dense skeleton 111 has 8 or 6 periods.
[0068] S3, Assembly of bracket body 1 includes the following steps:
[0069] A contrast ring is marked at the apex of each aortic dissection region, and a characteristic point is marked on the contrast ring. The marked point is located at the intersection of the sparse skeleton 112 of each aortic dissection region and the axis of symmetry of the stent body 1, and the angle formed by the marked point and the horizontal direction is denoted as . When implanting the stent body 1, ensure that the marked position of each region is located on the axis of symmetry of the true cavity, that is: Each region has 11 fiber modules, denoted as n. i (i = 1, 2, ..., 5), calculate the number of fiber modules 11 pairs for each region based on the height of the region axis and the height of a single fiber module 11, then:
[0070] Combining the number of cycles of the sparse skeleton 112 and dense skeleton 111 of each region fiber module 11, and (i = 1, 2, ..., 5), assemble the support frame.
[0071] In a further embodiment, the radius of the stent body 1 in each aortic dissection region is denoted as r. i (i = 1, 2, ..., 5), which is 5% to 10% larger than the average diameter of blood vessels in the region, and the assembled stent body 1 is tapered as a whole.
[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.
Claims
1. A spiral adaptive aortic dissection stent, characterized in that, The device includes a ring-shaped scaffold body composed of multiple sets of fiber modules. Adjacent sets of fiber modules are connected in a biomimetic manner, with a smooth transition using biodegradable polymers or composite materials. Each set of fiber modules is composed of two skeletons connected together: a dense skeleton and a sparse skeleton. The dense skeleton corresponds to the pseudo-cavity ratio range, and the sparse skeleton corresponds to the true cavity ratio range.
2. The spiral adaptive aortic dissection stent as described in claim 1, characterized in that, The skeleton at the connection between two adjacent fiber modules is densified, and the sparse support of the sparse skeleton is replaced with a dense support.
3. The spiral adaptive aortic dissection stent as described in claim 1, characterized in that, The main body of the support includes a strong helical support, wherein the dense and sparse skeletons of the strong helical support rotate in a helical manner.
4. The spiral adaptive aortic dissection stent as described in claim 1, characterized in that, The main body of the support includes a weak spiral support, wherein the dense and sparse skeletons of the weak spiral support do not rotate and are arranged in a straight line.
5. The spiral adaptive aortic dissection stent as described in claim 1, characterized in that, The scaffold body is a biodegradable material scaffold.
6. A design method for a spiral adaptive aortic dissection stent, characterized in that, The spiral adaptive aortic dissection stent is the spiral adaptive aortic dissection stent as described in any one of claims 1-5, and the design method includes the following steps: Based on the landmark anatomical locations and the major vascular branches of the abdominal aorta, aortic dissection is divided into zones; The stent fiber module design determines the period and number of the dense and sparse skeletons in each aortic dissection region; Assemble the support body.
7. The design method of the spiral adaptive aortic dissection stent as described in claim 6, characterized in that, The process of dividing aortic dissection into zones includes the following steps: Six characteristic horizontal sections are selected, denoted as S. i (i = 0, 1, ..., 5), plane S0 is located 2 cm below the apex of the lesser curve of the aortic arch to avoid the curved part of the aorta; plane S1 is located at the level of the aortic sinus; plane S2 is defined as the level of the apex of the diaphragm in human anatomy; plane S3 is the level above the opening of the celiac trunk; plane S4 is the level below the opening of the inferior renal artery; plane S5 is the level at the bifurcation of the abdominal aorta. Six characteristic horizontal sections divide the aorta into five aortic regions, denoted as C. i (i=1,2,…,5), where region C i Between plane S i-1 and plane S i Between these regions, the five aortic regions are named the proximal descending thoracic aorta region, the mid-descending thoracic aorta region, the distal descending thoracic aorta region, the visceral vessel region, and the abdominal aorta region. The length of the axis of each region is measured and denoted as h. i (i = 1, 2, ..., 5); The true cavity helix angle, true cavity initiation angle, and true cavity termination angle are measured for each characteristic horizontal section and denoted as α. i , and The true cavity percentage of each region is defined as the difference between the true cavity termination angle at the bottom of the region and the true cavity initiation angle at the top of the region, denoted as θ. i true Then there is The proportion of false cavity is recorded as Then there is Measure the maximum diameter of each characteristic horizontal section, and record it as follows:
8. The design method of the spiral adaptive aortic dissection stent as described in claim 7, characterized in that, Determining the period and number of the dense and sparse skeletons in each aortic dissection region includes the following steps: The radius of a single fiber module is r, and the height is d. The fiber radius is 5% to 10% of the normal aortic diameter in that region. The length of one cycle of the dense skeleton is denoted as l. dense The length of one period of the sparse skeleton is denoted as l. sparse The length of a single period in a sparse skeleton is twice the length of a single period in a dense skeleton, that is... l sparse ＝2l denes ； Generally, the length of one cycle in a dense skeleton is 1 / 12 of the scaffold circumference, and the length of one cycle in a sparse skeleton is 1 / 6 of the scaffold circumference. The number of periods for the dense and sparse skeletons in each region is denoted as T. i dense and T i sparse The number of periods in the sparse skeleton is calculated based on the proportion of the true cavity, i.e.: Where [] denotes the floor function, and the number of dense skeleton periods is T. i dense =12-2T i sparse .
9. The design method of the spiral adaptive aortic dissection stent as described in claim 8, characterized in that, The assembly of the support body includes the following steps: A contrast ring is marked at the apex of each aortic dissection region, and a feature point is marked on the contrast ring. The marked point is located at the intersection of the sparse skeleton and the axis of symmetry of the stent body in each aortic dissection region, and the angle formed by the mark and the horizontal direction is denoted as . When implanting the stent body, ensure that the marked position of each region is located on the axis of symmetry of the true cavity, that is: The number of fiber module pairs in each region is denoted as n. i (i = 1, 2, ..., 5), calculate the number of fiber module pairs for each region based on the height of the region axis and the height of a single group of fiber modules, then: Combining the number of cycles of the sparse and dense skeletons of each region's fiber module, T i dense and T i sparse Assemble the support frame (i = 1, 2, ..., 5).
10. The design method of the spiral adaptive aortic dissection stent as described in claim 9, characterized in that, The radius of the stent body in each aortic dissection region is denoted as r. i (i=1,2,...,5), which is 5% to 10% larger than the average diameter of blood vessels in the region, and the assembled stent body is tapered as a whole.