WO2010026498A1

WO2010026498A1 - Stent, for example for treating jugular veins, and corresponding delivery

Info

Publication number: WO2010026498A1
Application number: PCT/IB2009/052968
Authority: WO
Inventors: Paolo Zamboni; Roberto Galeotti
Original assignee: Zeppi, Augusto
Priority date: 2008-09-04
Filing date: 2009-07-08
Publication date: 2010-03-11
Also published as: ITTO20080654A1; AR075266A1

Abstract

A stent 10 for treating jugular veins comprising a generally tubular development body expandable between a radially contracted condition and a radially expanded condition, with: - a first portion 11 having a first 11a and a second lib end, - a second portion 12 joined to the second end lib of the first portion 11, and - an end collar portion 13 extended starting from the first end 11a of the first portion 11. At least in the radially expanded condition, the second portion 12 has a length and diameter greater than the length and diameter of the first portion 11 and the end collar portion 13 is suitable to acquire a flared development outwards.

Description

"Stent, for example for treating jugular veins, and corresponding delivery"

Field of the invention The present disclosure refers to stents, for example for treating peripheral vessels.

The present disclosure was devised with special attention to the possible use for treating jugular veins. Description of the prior art Treatment of vein stenosis, associated or not associated to multiple sclerosis, may be performed through the PTA (Percutaneous Transluminal Angioplasty) technique, that provides for the use of dilatation catheters with distal balloon positioned on the stenotic venous segment and inflated from outside (see, for example, the solutions described in documents PCT/IB2008/000621 and PCT/IB2008/000623) .

Otherwise known from various patent documents are stents having portions with different diameter dimensions: see for example EP-A-O 888 758 (regarding an hourglass- shaped esophageal stent) , WO-A-2007/044931 (regarding a generally trumpet-shaped endoluminal prosthesis), WO-A- 02/071974 (regarding a stent for the arterialization of the coronary sinus and the perfusion of the myocardium having a general profile definable as "fish-shaped"), US-A- 2005/0222668 (illustrating a vascular aortic prosthesis adapted to exhibit various shapes) and also US-A- 2003/0040804 (illustrating a device for creating the feeling of satiety substantially similar to a stent expandable in the pyloric region) .

Objects and summary of the invention

In particular, in the case of jugular veins, the inventors noticed the possible presence of restenosis some months after the PTA; this also in cases well dilatable by a compliant balloon. The inventors likewise noticed that this possibility in many cases is due to the presence, in the distal jugular lumen (at the junction in the brachial- cephalic trunk), of malformed or malfunctioning valve flaps. Following possible uncoordinated and unpredictable movements, these valve flaps may obstruct the cerebral flow, even during the most favourable physiological phases thereto like during inspiration, turning into actual septa.

Under such situation forcing of such valve flaps against the vessel wall using a stent would be desirable. Treatment or prevention using a stent useable for treating jugular stenosis or restenosis would also be desirable to improve the result of the venous stenosis treated using stenting in other regions of the venous tree with respect to the PTA alone.

However, use of tubular stents of fixed gauge and short length does not allow to obtain the required adherence against the wall to prevent migration. Furthermore, in case of jugular veins, the possible projection into the brachial- cephalic trunk of the distal end of the stent causes a mechanical obstacle problem to the outlet flow from the upper limb facilitating thrombosis. Still, it would be desirable to obtain a differentiating dilating action, greater for the proximal end and lower for the distal portion.

The present invention has the object of providing a stent capable of meeting all the needs outlined above.

According to the invention, such object is obtained by means of a stent having the characteristics referred to in the claims that follow. The invention also regards the corresponding delivery kit. The claims form an integral part of the technical disclosure provided herein in relation to the invention.

In an embodiment, the solution described herein provides for a stent which, in the radially expanded condition, has a shape capable of adjusting to the particular upside-down-bottle shape of the jugular, also overcoming drawbacks linked to the position of the malfunctioning stenosis associated with multiple sclerosis in proximity to the subclavian outlet.

Brief description of the attached representations Now, the invention shall be described, strictly for exemplifying and non-limiting purposes, with reference to the attached representations, wherein: - figure 1 schematically illustrates a positioning kit comprising a stent mounted on an introduction catheter; figure 2 schematically illustrates the general geometry of a stent in a radially expanded condition;

- figures 3 and 4 illustrate two possible embodiments of a stent; and figures 5 and 6 illustrate possible methods for positioning a stent.

Detailed description of embodiments Illustrated in the following description are various specific details aimed at an in-depth understanding of the embodiments. The embodiments may be obtained without one or more specific details, or through other methods, components, materials etc. In other cases, known structures, materials or operations are not shown or described in detail to avoid obscuring the various aspects of the embodiments. Reference to "an embodiment" in this description indicates that a particular configuration, structure or characteristic described regarding the embodiment is included in at least one embodiment. Hence, expressions such as "in an embodiment", possibly present in various parts of this description do not necessarily refer to the same embodiment. Furthermore, particular configurations, structures or characteristics may be combined in any suitable manner in one or more embodiments. References herein are used for facilitating the reader and thus they do not define the scope of protection or the scope of the embodiments.

Figure 1 schematically illustrates a stent 10 mounted at the distal end of an introduction catheter C in such a manner to be positioned through catheterism into a jugular vein at the distal jugular lumen (at the brachial-cephalic trunk junction) . In particular, figures 5 and 6 illustrate the possible positioning in the distal section (functionally) of an internal jugular vein VGI, at the junction in the subclavian vein VS.

In an embodiment, the catheter C for positioning the stent 10 is compatible with 6 - 8 French introducers; it is flexible, smooth sliding, with resistance to kinking even in curvilinear sections and it is 100-120 cm long.

The term stent is generally used to indicate a device suitable to be positioned in a body lumen, such as for example a blood vessel, for interacting with the wall of the lumen in such a manner to restore and/or maintain the patency of the lumen itself, for example by forcing against the wall of the lumen formations of various types otherwise suitable to reduce or obstruct the section of the lumen.

In an embodiment, the stent 10 comprises a generally tubular shaped body expandable between: - a radially contracted condition, wherein the stent 10, mounted on the positioning catheter, can be introduced into the body of the patient and moved forward up to reaching the positioning site, and

- a radially expanded condition, wherein the stent, located in the positioning site, is capable of cooperating with the wall of the lumen obtaining the desired function.

Various solutions can be used in order to obtain the radial expansion of the stent from the radially contracted position to the radially expanded position. For example, figure 1 schematically refers to a solution wherein the stent 10 is mounted ("crimped") on the distal section of a balloon catheter. The deployment (radial expansion) of the stent is in this case obtained by inflating the balloon.

In an embodiment, given that the stent illustrated herein comprises, as better outlined hereinafter, a first and a second portion intended to be dilated at different degrees, as well as an end collar part intended to acquire a flared development, the balloon part of the catheter may comprise two or more sections intended to be expanded in different ways. A balloon catheter of this type is described for example in document PCT/IB2008/000621, mentioned previously. In an embodiment, the stent 10 is made, at least partially, of self-expanding material (for example nitinol) . In this case, while it is moved forward towards the positioning site, the stent is forced in a radially contracted position by a tubular sheath (or an equivalent radial constriction element) . Upon reaching the positioning site, the constriction element releases the stent, which is thus left free to expand towards the radially expanded condition.

The general concepts outlined above are well known in the stents industry and they do not require a further detailed description herein. Same case substantially applies also regarding the technology for making the stent (for example cutting starting from a microtube, for example using a laser beam) . The following description refers to characteristics acquired by the stent 10 at least in the radially expanded condition: the term "at least" shall be interpreted in the sense that, in some embodiments, some of such characteristics may already be present in the stent 10 prior to deployment. However, it shall be presumed hereinafter that, in the radially contracted condition that precedes deployment, the stent 10 shall have the shape represented in figure 1.

In the solution described herein, the stent 10 comprises a body having a generally tubular development expandable between a radially contracted condition

(represented in figure 1) towards a radially expanded condition (referred to in figures 2 - 4) .

The body of the stent 10 comprises a first portion 11, and a second portion 12, as well as an end collar portion, indicated with 13.

The first portion 11 in turn has a first end 11a and a second end lib. The second portion 12 is joined to the second end lib of the first portion 11. The collar portion 13 is extended starting from the first end 11a of the first portion 11.

As clearly observable in figures 2 - 4 - at least in the expanded condition - the second portion 12 has a larger diameter than the diameter of the first portion 11. In the illustrated embodiment, not essential, wherein the two portions 11 and 12 form a single piece, the two portions 11 and 12 are thus joined together through a part of the body of the stent having a frustoconical development.

The second portion 12 is also longer with respect to the first portion 11. In the represented embodiment this occurs both in the radially contracted condition, and in the radially expanded condition, it being presumable that during the radial expansion movement the length of the two portions 11 and 12 of the stent remains constant (as in the case of the embodiment of figure 3) or is subjected to slight shortening. The stent 10 is thus capable of having, in its "active" condition, i.e. in its expanded condition, an overall "upside-down bottle" or "extended cup" shape, capable of adjusting to the morphology of the internal jugular vein in the section comprised between the outlet, where the vein usually has a diameter of 8-10 mm, and the submandibular cervical section, where it can also reach 25- 30 mm of diameter, for a total length of about 60-100 mm.

Embodiments of the solution described herein provide for that the first portion 11 of the stent (tubular portion to be connected at the orifice of the vein VGI - see figures

5 and 6) is approximately 10 - 20 mm long and has an approximately 12 mm diameter (in expanded condition) .

Embodiments of the solution described herein also provide for that the second portion 12 of the stent (cranial portion, to be positioned in the internal jugular vein VGI in its cervical section) is approximately 40 - 80 mm long and has an approximately 20-30 mm diameter (still in expanded condition) .

The collar portion 13 is capable of acquiring (due to a positive dilation action, or due to its self-expandability characteristics) a flared (or "bell-shaped") morphology diverging outwards. Such morphology allows the collar portion 13 - proximal in the condition of use - to project to the level of the jugulo-subclavian junction as illustrated in figures 5 and 6. All this not significantly altering the flow of such vessels junction. In an embodiment, the collar portion 13 is deformable in the direction of the divergence for example due to the fact that it has "a petal-like" configuration.

The collar portion 13 may be possibly folded on the periosteal wall around the orifice of the internal jugular vein VGI inflating a balloon in the brachial-cephalic trunk, for example with a manoeuvre analogous to that performed for stenting the renal artery at the level of the orifice between the latter and the aorta, or in other bifurcated vascular sections. The end of the stent 10 may thus abut against the upper wall of the brachial-cephalic trunk, preventing it from projecting into the lumen (figure 6)

Figure 3 illustrates the possibility to obtain the stent 10 with a geometry comprising a plurality of annular elements 100 arranged cascading in the direction of the length of the stent 10. In such geometry, adjacent annular elements 100 are connected by link elements 102 extended

(with linear or wavy trajectory in the direction of the length of the stent 10) . Each annular element 100 has a general serpentine development: this solution allows the length of the stent to remain unaltered during the expansion movement .

Figure 4 illustrates the possibility of obtaining the stent 10 with a mesh geometry, wherein the expansion movement of the stent is accompanied by at least one slight longitudinal contraction.

The illustrated embodiments are suitable for providing a stent 10 made of self-expandable material (e.g. nitinol) and/or flexible material (e.g. steel), capable of expressing a high dilative action, especially regarding the first tubular portion 11.

The dimensional values indicated herein, per se not essential, shall obviously be understood taking into account the tolerances usually associated to the construction and measurement thereof. Experiments carried out by the Inventors showed that the presence of septas and/or valves oriented in non- physiological direction in the junction section of the internal jugular may be provided with stents shaped as described herein made partially or entirely using an absorbable matrix. The latter allows keeping both the septa and the irregular valve cusps against the wall for a few months. During this period, the absorbable matrix may allow incorporating these deposits protruding into the lumen and making them uniform in the context of the vessel wall, disappearing gradually up to the total recovery upon completion of the absorption process. The absorbable material may be made of polymers absorbable through non- enzymatic hydrolysis mechanisms (polyglycolic acid, polyglycolactic acid, etc) , or even material absorbable through enzymatic hydrolysis mechanisms (collagen, etc) , in a more modern manner through carbon polymers, or even through combined absorbable and non-absorbable material .

The absorbable material creates a remodelling of the vessel preventing septa or irregular valves from protruding into the lumen hindering correct passage of blood when breathing. However, it is simultaneously more advantageous given that after obtaining the desired effect it disappears within a few months reducing the restenosis stimulus due to intima-media hyperplasia, or formation of foreign body granuloma.

Without prejudice to the underlying principle of the invention, the details and embodiments may vary, even significantly, with respect to what has been described herein by way of non-limiting example only, without departing from the scope of the invention as defined by the claims that follow.

Claims

1. Stent (10) comprising a generally tubular development body expandable from a radially contracted condition to a radially expanded condition, said body comprising :

- a first portion (11) having a first (Ha) and a second (lib) end, a second portion (12) joined to said second end (Hb) of said first portion (11), and

- an end collar portion (13) extended starting from said first end (Ha) of said first portion (11) , and wherein, at least in said radially expanded condition, - said second portion (12) has a larger diameter with respect to the diameter of said first portion (11) and said end collar portion (13) is suitable to acquire a flared development outwards,

- said second portion (12) has a greater length with respect to the length of said first portion (11) .

2. Stent (10) according to claim 1, wherein, at least in said radially expanded condition, said first (11) and said second (12) portion are joined together through a part of the body of the stent having a frustoconical development.

3. Stent (10) according to any one of the preceding claims, wherein, in said radially expanded condition, said first portion (11) of the stent has an approximately 12 mm diameter.

4. Stent (10) according to any one of the preceding claims, wherein, in said radially expanded condition, said second portion (12) of the stent has an approximately 20 - 30 mm diameter.

5. Stent (10) according to any one of the preceding claims, wherein said first portion (11) of the stent is approximately 10 - 20 mm long.

6. Stent (10) according to any one of the preceding claims, wherein said second portion (12) of the stent is approximately 40 - 80 mm long.

7. Stent (10) according to any one of the preceding claims, wherein said end collar portion (13) has a petal- like configuration.

8. Stent (10) according to any one of the preceding claims, made, at least partially, of self-expandable material .

9. Stent (10) according to any one of the preceding claims, made, at least partially, of absorbable material.

10. Stent (10) according to claim ^"*, wherein said absorbable material is selected from among:

- polymers absorbable through non-enzymatic hydrolysis mechanisms, preferably polyglycolic or polyglycolactic acid, materials absorbable through enzymatic hydrolysis mechanisms, preferably collagen,

- carbon polymers.

11. A kit comprising:

- a catheter (C) for introducing a stent, and - a stent (10) according to any one of claims 1 - 10 mounted on said catheter (C) .