Vascular and bodily duct treatment devices

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DESCRIPTION

Vascular and body duct treatment devices

TECHNICAL FIELD

This application relates to devices and procedures for treating the vasculature and other ducts of the body.

BACKGROUND

Self-expanding prostheses, such as stents, covered stents, vascular grafts, flow diverters, and the like have been developed to treat ducts in the body. Many of the prostheses have been developed to treat blockages within the vasculature and also aneurysms that occur in the brain. What is needed are improved treatment methods and devices for treating the vasculature and other body conduits, such as, for example, aneurysms, strictures, embolic obstructions, and the like.

US 2011/009950 describes a duct blockage removal device having filament elements with different width dimensions.

DESCRIPTION SUMMARY

According to the invention, a duct obstruction removal device according to claim 1 is described. A preferred embodiment is described in claim 2.

BRIEF DESCRIPTION OF THE DRAWINGS

Alternative implementations of the present description are described herein with reference to the drawings, in which:

Figure 42A illustrates a two-dimensional plan view of clot removal devices in accordance with some implementations.

Figure 42B illustrates an enlarged two-dimensional plan view of the tapered proximal end portion of the extraction device depicted in Figure 45A.

Figure 43 illustrates a two-dimensional plan view of a more proximal cell structure in accordance with some implementations.

Figure 44 illustrates a two-dimensional plan view of a more proximal cell structure in accordance with some implementations.

DETAILED DESCRIPTION

FIG. 42A is a two-dimensional view of a duct obstruction removal device 450 in accordance with one implementation. The extraction device 450 comprises an expandable element having a conical proximal end portion 451, a cylindrical main body portion 452, and a conical distal end portion 453. The outermost cell structures in the conical proximal end portion have outer wall segments that form a first and second rail segment 454 and 455, respectively. Each of the rail segments 454 and 455 extend from a more proximal end of the expandable element to a position at or near the proximal end of the cylindrical main body portion 452. In the implementation of Figure 42, each of the rail segments 454 and 455 are corrugated. A proximal antenna 457 extends proximally from a more proximal cell structure 456.

The most proximal cell structure 456, as shown in greater detail in FIG. 42B, comprises first and second outer filaments 460 and 461, respectively, and first and second inner filaments 462 and 463, respectively. As shown in the arrangement of Figure 42B, the first outer filament 460 and a first part 461a of the second outer filament 46.1 are straight in the two-dimensional arrangement while the first inner filament 462, the second inner filament 463 and the second inner filament 461b of filament 461 are curvilinear in the two-dimensional arrangement. In the fabricated three-dimensional configuration, the first outer filament 460 and the first portion 461a of the second outer filament 461 are curved and do not exhibit crimps. As a result of being oriented at the proximal end of the expandable element and being coextensive with the proximal antenna, the straight filament segments of the more proximal cell structure 456 increase the pushability of the extraction device 450 as it is delivered, across the anatomy of a patient, compared to retrieval devices that have a more proximal cell structure with only curved filaments in the two-dimensional arrangement.

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In some implementations, the total length of the filaments 460 and 462 (LI) and the total length of the filaments 461 and 463 (L2) are substantially equal in order to promote a nesting of the filaments when the expandable element passes the expanded state. to the unexpanded state. According to some implementations, the length difference between LI and L2 is less than 5.0%, while in other implementations, the length difference between LI and L2 is less than 1.0%.

Figure 43 illustrates a variation of the more proximal cell structure 456. As shown, each of the filaments 460 and 461 has a zone of reduced width 464 and 465, respectively, which are located adjacent to their junction 466 with the proximal antenna 457. The inclusion of the reduced width zones 464 and 465 locally increases the ability to collapse of the more proximal cell structure by reducing the amount of force required to initiate and effect the collapse. Thus, for example, when the extraction device 450 is first inserted into an introducer sheath for placement within a delivery catheter or is withdrawn into a delivery catheter after the expandable element has been implanted in a patient, the zones The reduced width 464 and 465 cause the filaments 460 and 461 to bend more easily in the joint area 466 with less force than would otherwise be required without the reduced width areas. This makes the extraction device 450 more manageable when manipulated by healthcare professionals when the extraction device 450 is first being inserted into the delivery catheter, thus reducing the likelihood of the extraction device being damaged during the process. introduction. As described above, after the extraction device 450 has been inserted and expanded within a patient's conduit, there may be occasions when the extraction device is withdrawn proximally back into the delivery catheter. This can occur, for example, when the extraction device is incorrectly positioned in the canal or upon completion of an extraction procedure. In each of these cases, because less force is required to collapse the expandable member of the extraction device, several advantages are obtained. One advantage is that it reduces the likelihood that the removal device 450 will act on the delivery catheter in a manner that causes inadvertent displacement of the delivery catheter within the patient conduit. Another advantage is that it reduces the likelihood of excessive force being applied at the junction between the proximal antenna 457 and the elongated wire (eg, elongated wire 40 shown in FIG. 1A) that would result in a failure of the junction.

In the implementation of FIG. 43, the reduced width zones 464 and 465 comprise tapers. In other implementations, the areas of reduced width are indicated by a stepped reduction in the width of the filament. The amount by which the width is reduced in zones 464 and 465 will vary according to the nominal widths of filaments 460 and 461. In either case, it is important that the amount of reduction in width is consistent with the radial force and structural integrity requirements of the expandable member. A reduction in width in the as-manufactured cut state of between about 5.0% and about 20.0% has been found to be adequate for filaments having a nominal width of between about 0.0057 inches and about 0. 0.0027 inches (between about 0.145mm and about 0.068mm), with a range of between about 10.0% and about 20.0% reduction in width being preferred. In one embodiment, the width dimension W1 of filaments 460 and 461 is approximately 0.0053 inches (approximately 0.135 mm), with the minimum width dimension of the reduced width areas being 0.0047 inches (0.12 mm). ). In another implementation, the width dimension W1 of the filaments 460 and 461 is approximately 0.0057 inches (approximately 0.145 mm), with the minimum width dimension of the reduced width areas being 0.0046 inches (0.117 mm).

In some implementations, the cut width dimensions of filaments 460 and 461 are different, with the width dimension of their respective reduced width areas 464 and 465 also being different. For example, in one implementation filament 460 has a width dimension of approximately 0.0050 inches (0.127 mm), filament 461 has a width dimension of approximately 0.0057 inches (approximately 0.145 mm), and the width areas Reduced 464 and 465 have width dimensions of about 0.0042 inches (about 0.107 mm) and about 0.0046 inches (about 0.117 mm), respectively.

Figure 44 shows another variation of the more proximal cell structure 457 in which the outer filaments 460 and 461 comprise a proximal section 467, a mid section 468, and a distal section 469. Because the width dimensions of the outermost strands 460 and 461 of the more proximal cell structure 456 become substantially larger than most of the strands in the remaining portion of the extraction device 450 in order to improve pushability of the expandable element, the thickness of material at the junctions 471 and 472 at the distal end of the filaments can impede the expandable element's ability to collapse. For this reason, in the implementation of Figure 44, the distal sections 469 have a reduced width dimension in order to reduce the amount of material that occupies the attachment regions 471 and 472. Although Figure 44 also shows the proximal sections 467 that have a reduced width dimension (similar to that described above), in some implementations this is not the case. As described above, the reduced width sections may comprise tapers and / or steps.

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Another advantage of the implementation depicted in Figure 44 is that the midsection 468 of the filaments 460 and 461 can be of sufficient width to improve the visibility of the device under fluoroscopy without materially affecting the ability of the proximal end of the tapered proximal end region. 451 to collapse or to otherwise assume its unexpanded state. According to one implementation, the width dimension of the intermediate sections of the filaments 468 is approximately 0.0053 inches (approximately 0.135 mm) and the minimum width dimension of the proximal and distal sections 467 and 469 is 0.0047. inches (0.119 mm) and 0.0041 inches (0.104 mm), respectively. As with some of the implementations of Figure 43, in some implementations of Figure 44 the width dimensions of filaments 460 and 461 are different, with the width dimension of one or more of their respective proximal sections being different. middle and distal sections

Although the above description contains many specifications, such specifications should not be construed as limitations on the scope of the description, but merely as examples of preferred embodiments thereof. For example, dimensions other than those listed above are contemplated. For example, extraction devices having any expanded diameter between 1.0 and 100.0 millimeters and lengths of up to 5.0 to 10.0 centimeters are contemplated. Furthermore, it is appreciated that many of the features described herein are interchangeable between the various implementations. Those skilled in the art will appreciate many other possible variations that are within the scope and spirit of the description. Furthermore, it should be appreciated that the delivery of a vascular treatment device of the implementations described herein can be accomplished with the use of a catheter, sheath, or any other device that is capable of transporting the device with the expandable element in a state. compressed to the treatment site and allowing subsequent implantation of the expandable element in a vascular treatment site. The vascular treatment site may be (1) in the neck of an aneurysm to divert flow and / or facilitate the placement of coils or other similar structures within the sac of an aneurysm, (2) at the site of an embolic obstruction with the purpose of removing the embolic obstruction, (3) at the site of a stenosis in order to dilate the stenosis to increase blood flow through the vasculature, etc.