Patent Application
20110029060
The present invention refers to medical devices. Particularly it relates to stent devices and balloon catheter devices. In the most particular aspect of the invention it relates to structures with at least two different lamellar sections used in such a medical device, especially in a balloon on a balloon catheter device carrying a stent comprising at least one layer with at least two lamellar sections different by their elasticity, like shore hardness, and its use in a variety of medical procedures to treat medical conditions in animal and human patients.
This invention relates to medical devices, especially to stent carrying balloon catheters, for use in angioplasty and other procedures of vessel repair. Angioplasty is an efficient and successful method of opening stenoses in the vascular system.
In a popular form of angioplasty, a balloon catheter is advanced through the vascular system until the balloon, which is carried at the distal end of a catheter shaft, and which may carry an expandable stent, is positioned across the stenosis or damaged vessel. By inflating, the balloon pressure is applied to the obstruction, which is moved by pressing it against the inner wall of the vessel, whereby the vessel is opened for improved flow. Due to the expansion of the balloon, the stent, which—if used—is situated on the balloon, is also expanded for aiding in repairing the vessel wall and hindering obstruction. The stent is then released by deflating the balloon reducing its circumference until refolding of the balloon. This refolding is a critical step in this form of angioplasty. In some cases the refolding is insufficient leading to deformations, in general called “pan-caking”, in which the refolded balloon does not reach the optimal minimum—mostly circular—size, but shows edges and bulges. When withdrawing the balloon catheter with the refolded balloon these bulges and edges might damage the fine vessel of the vascular system.
There are various types of balloon catheters. One type is fed over a guide wire (i.e., “over-the-wire” catheters) and another type serves as its own guide wire (“fixed-wire” catheters). Variations of these two basic types have been developed: the so called “rapid exchange” type, “innerless” catheters, and others. The term “balloon catheter” as defined in this invention is meant to include all the various types of angioplasty catheters which carry a balloon for performing angioplasty and any other type of stent carrying balloon catheter. Balloon catheters also have a wide variety of inner structure, such as different lumen design, of which there are at least three basic types: triple lumen, dual lumen and co-axial lumen. All these varieties of internal structure and design variations are included in the definition “balloon catheter” herein.
If a balloon catheter is used in percutaneous transluminal coronary angioplasty (PTCA), it is typically advanced through a guide catheter to a preselected vessel location, such as the aorta, for example. Using fluoroscopy, the surgeon advances the catheter until the balloon is located across the stenosis or obstruction. This may involve the use of a guide wire over which the catheter is moved or alternatively the catheter may act as its own guide wire.
The use of stents, balloons, catheters, especially balloon catheters and other medical devices etc. in minimal invasive surgery, especially in the cardiovascular field, has—over the last years—shown a high growth. As a consequence, the need for modifications to the materials used fulfilling the highly specialized needs in the field of different medicinal devices has clearly risen. Especially in the field of cardiovascularily used balloons, there was a clear desire for a modified material showing a suitable compliance, a high burst pressure, but also a good and dependable refolding behaviour, especially avoiding “pan-caking”, but also “dog-boning” (an inflation of the balloon outside the stenotic area of the vessel).
The present invention is aimed at guiding the refolding into an optimized form being equal or very similar to the structure of the balloon on the balloon catheter before expanding. The object of the present invention is to improve the refolding behavior of the balloon by providing different lamellar sections in the balloon material having different elasticities, like compliance/shore hardness. This invention thus avoids sub-optimal refolding of the balloon after expansion, especially “pan-caking”, associated with prior solutions, but also the dreaded “dog-boning” during balloon expansion.
The present invention is directed in one embodiment to a medical device comprising an expandable and contractible member, which is desirably a medical balloon, with at least one first polymeric-layer consisting of at least one lamellar section A and an equal number of lamellar sections B. These lamellar sections A and B are disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member, with adjacent sections having a different elasticity, expressed as different shore hardness, E-modulus, tensile strength, elongation at break, or compliance, but preferably expressed as a different shore hardness. By choosing different elasticity, like shore hardness for the lamellar sections A and B refolding of the expandable and contractible member, which is desirably a medical balloon, is greatly helped. After placing a device, e.g. the stent, in the desired position, e.g. in the coronary vessel in PTCA, using pressure-expansion of the balloon (thus also expanding the stent into the desired state and position), the balloon is deflated. The fact that the sections A and B react differently to the internal pressure of the balloon is also reflected in their behaviour when the balloon is refolding, with the sections with lower elasticity (higher shore hardness) guiding—quasi as a scaffold—the desired refolding ideally into the original form.
In another embodiment, the invention is further directed to a medical device being a delivery apparatus (preferably a balloon catheter) comprising a first expandable and contractible member (which desirably is a medical balloon) for delivering at least one second medical device. The second medical device is an expandable medical device disposed about the first expandable and contractible member and desirably is a stent. In this medical device, the expandable and contractible member is desirably a medical balloon and has at least one first polymeric-layer consisting of at least one lamellar section A and an equal number of lamellar sections B. These lamellar sections A and B are disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member, with adjacent sections having a different elasticity, expressed as different shore hardness, E-modulus, tensile strength, elongation at break, or compliance, but preferably expressed as a different shore hardness.
In yet another embodiment, the invention is directed to a method for improving the refolding behaviour of an expandable and contractible member, which desirably is a medical balloon. In this method, at least one first polymeric-layer of an expandable and contractible member consisting of at least one lamellar section A and an equal number of lamellar sections B disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member is provided. The adjacent sections A and B have a different elasticity.
In a further embodiment, the invention is directed to a method of producing a medical device according to the invention. In this method, the lamellar section/s A and the lamellar section/s B are co-extruded, when producing the first polymeric-layer of the expandable and contractible member.
In another further embodiment, the invention is directed to a method of producing a certain embodiment of the medical device according to the invention. In this method, the lamellar section/s A and the lamellar section/s B of the expandable and contractible member are either simultaneously or consecutively extruded onto a second polymeric-layer.
In a further embodiment, the invention is directed to a method of treatment of a disease, like a cardiovascular disease, especially a stenosis, using in a patient, being a mammal, especially a human, in need thereof a medical device according to the invention, desirably in minimal invasive surgery like PTCA.
In yet another embodiment, the invention is directed to the use of a medical device according to the invention for the treatment of a disease, like a cardiovascular disease, especially a stenosis, especially through minimal invasive surgery like PTCA.
These and other objects and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
Without this being depicted in
While the invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated.
In one embodiment as depicted in
As a general remark, elasticity (of the polymer) as used herein can be expressed in different ways like shore hardness, E-modulus, tensile strength, elongation at break, or compliance, but in the context of this invention preferably is expressed as different shore hardness, even though the other expressions for elasticity like E-modulus, tensile strength, elongation at break, or compliance may also be used.
In this embodiment, the expandable and contractible member (B) desirably is a medical balloon. The medical balloon (B) is capable of being expanded and contracted. Desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 2 each of lamellar sections A (5) and lamellar sections B (6). In another embodiment, desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 3 each of lamellar sections A (5) and lamellar sections B (6). Desirably lamellar section A (5) and lamellar section B (6) consist of two different polymeric materials, especially different polymers or block-co-polymers selected from, e.g., Nylons, PEBA or mixtures thereof.
In one embodiment of the medical device according to the invention, desirably the expandable and contractible member (3), the medical balloon, comprises an additional second polymeric-layer (8) disposed within the first polymeric layer (4). In another alternative embodiment, the expandable and contractible member (3) comprises an additional third polymeric-layer (9) disposed about the first polymeric layer (4), and in a third alternative embodiment the expandable and contractible member (3) comprises an additional third polymeric-layer (9) disposed about the first polymeric layer (4) and an additional second polymeric-layer (8) disposed within the first polymeric layer (4). Desirably the second polymeric-layer (8), in another alternative embodiment and/or the third polymeric layer (9) consists of PEBA or Nylon or mixtures thereof. Advantageously, the second (or third) polymeric layer, in this embodiment, provides the strength and air tightness to the medical balloon, allowing the sections A and B to not necessarily be tightly bound to each other and also to be selected from material usually not used in a medical balloon.
In another embodiment of the medical device according to the invention as depicted for example in
As a general remark, “adhesive”, as defined in this application encompasses all forms of interaction between surfaces transferring adhesion between them including friction by a rough surface or simply “tacky” surfaces provided by certain sorts of polymeric material like e.g. certain sorts of PEBA.
As a general information and with the focus of this invention on balloon material for balloon catheters, one of the main parameters of a balloon is compliance, the change of the balloon diameter with rising inflation pressure; as used herein three categories are identified:
Non-compliant (NC) with a diameter increase of up to 0.55% per bar;
Semi-compliant (SC) with a diameter increase of between 0.55 to 0.8% per bar; and
Compliant with a diameter increase over 0.8% per bar as the balloon is pressurized from an inflation pressure between the nominal pressure and rated burst pressure.
While a certain level of compliance is needed to allow the compression of the arterio-sclerotic plaque in a vessel, an amount of pressure expressed on the stenosis as executed by a more non-compliant balloon is also needed. Also semi-compliant and compliant balloons are more prone to failure during PTCA and also “dog-boning”, an inflation of the balloon outside the stenotic area of the vessel resulting sometimes in devastating stress on the healthy part of the vessel.
Another main parameter of a balloon in a balloon catheter device is burst pressure, the pressure a balloon in a balloon catheter device can withstand from within before bursting. While a certain degree of pressure expressed on the stenosis is a clear necessity for the function of a balloon catheter device, the risks set to this pressure by the obviously devastating results of a possible burst of the balloon while in a lumen, e.g. of a vessel, do considerably limit the options given to a practitioner in using this device. Thus, also a high resistance to burst pressure is mostly a wanted effect in the balloon of a balloon catheter device.
In one embodiment, the medical device (D) is a delivery apparatus for delivering at least one second medical device. Desirably the medical device is a delivery apparatus with a stent, a stent graft, a graft or a graft connector as second medical device. Very desirably the medical device is a delivery apparatus with a stent as second medical device. In one embodiment, this delivery apparatus comprises a catheter with a medical balloon (3) as expandable and contractible member (3), thus being a balloon catheter. Thereby the second medical device, the stent (7), is disposed about the medical balloon (3) (the first expandable and contractible member). Additional details concerning the construction of suitable stent delivery apparatuses for use in the invention may be found in U.S. Pat. Nos. 6,036,697, 5,893,868 and 5,957,930 and elsewhere in the patent literature. Any suitable stent may be used whether formed of metal or of polymeric material or of another material. Examples of suitable stents may be found in U.S. Pat. Nos. 6,533,809 and 6,602,285.
The medical balloon (3) is capable of being expanded and contracted. Desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 2 each of lamellar sections A (5) and lamellar sections B (6). In another embodiment, desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 3 each of lamellar sections A (5) and lamellar sections B (6). Desirably lamellar section A (5) and lamellar section B (6) consist of two different polymeric materials, especially different polymers or block-co-polymers like selected from e.g. Nylons, PEBA or mixtures thereof.
The terms “Balloon”, “Medical Balloon” or “balloon material” in the context of this invention especially means a balloon like those used in balloon angioplasty and the material used for these balloons, especially balloon catheters. In this, e.g., a balloon catheter is inserted into an artery or other lumen and advanced to e.g. a narrowing in a coronary artery. The balloon is then inflated by gas or fluids to enlarge the lumen and/or—often—to place a medical device.
The term “Stent” means an elongate implant with a hollow interior and at least two orifices and usually a circular or elliptical, but also any other, cross section, preferably with a perforated, lattice-like structure that is implanted into vessels, in particular blood vessels, to restore and maintain the vessels patent and functional.
The term “Graft” means an elongate implant with a hollow interior and with at least two orifices and usually circular or elliptical, but also any other, a cross section and with at least one closed polymer surface which is homogeneous or, optionally, woven from various strands. The surface preferably is impermeable to corpuscular constituents of blood and/or for water, so that the implant serves as a vascular prosthesis and is usually employed for damaged vessels or in place of vessels.
The term “Stent graft” means a connection between a stent and a graft. A stent graft preferably comprises a vascular prosthesis reinforced with a stent (both as defined above), wherein a polymer layer is homogeneous or, optionally, woven, knitted plaited etc. from various strands and is either impermeable for corpuscular constituents of blood and/or for water or can also be permeable. More preferably, the stent has on at least 20% of its surface a perforated (lattice-like), preferably metallic, outer layer and at least one closed polymer layer that is located inside or outside the stent outer layer. The closed polymer layer may be homogeneous or, optionally, woven from various strands, and is impermeable for corpuscular constituents of blood and/or for water. Optionally, where the closed polymer layer is disposed inside the metallic outer layer, a further perforated (lattice-like), preferably metallic, inner layer may be located inside the polymer layer.
The term “Graft connector” means an implant that connects at least two hollow organs, vessels or grafts, consists of the materials defined for grafts or stent grafts and/or has the structure defined for the latter. Preferably, a graft connector has at least two, three or four, orifices, arranged, for example, as an asymmetric “T” shape.
The term “Catheter” means a tubular instrument intended for introduction into hollow organs. More preferably, a catheter may be designed for use in guiding other catheters, or for angiography, ultrasound imaging, or—especially—balloon catheters for dilatation or stent delivery. This includes also a “Catheter pump” meaning a catheter provided on its tip with a propeller able to assist the pumping of the myocardium.
In one embodiment of the medical device as a delivery apparatus for delivering at least one second medical device, especially a stent, according to the invention desirably the expandable and contractible member (3), the medical balloon, comprises an additional second polymeric-layer (8) disposed within the first polymeric layer (4). In another alternative embodiment, the expandable and contractible member (3) comprises an additional third polymeric-layer (9) disposed about the first polymeric layer (4), and in a third alternative embodiment the expandable and contractible member (3) comprises an additional third polymeric-layer (9) disposed about the first polymeric layer (4) and an additional second polymeric-layer (8) disposed within the first polymeric layer (4). Desirably the second polymeric-layer (8), in another alternative embodiment, and/or the third polymeric layer (9) consists of PEBA or Nylon or mixtures thereof. Advantageously the second (or third) polymeric layer, in this embodiment, provides the strength and air tightness to the medical balloon, allowing the sections A and B to not necessarily having to be tightly bound to each other and also to be selected from material usually not used in a medical balloon.
In this embodiment of the medical device as a delivery apparatus for delivering at least one second medical device, especially a stent, according to the invention, desirably the polymeric material, of which lamellar section A (5) or lamellar section B (6) consists, is adhesive, while the other is not, or one of lamellar section A (5) or lamellar section B (6) is layered with an adhesive (10), while the other is not. Adhesives as defined in this invention especially are mild adhesives, preferably an adhesive being pressure sensitive and selected as to release the second medical device (stent) (7) from the expandable and contractible member (3) (the medical balloon) upon pressure being applied from within the second medical device aiming at distancing the stent (7) from the adhesive (10) of the balloon. Selected pressure sensitive adhesives, include silicone type pressure sensitive adhesives, acrylic type pressure sensitive adhesives and urethane type pressure sensitive adhesives. Examples of acrylic type pressure sensitive adhesives include NeoTac A-580, NeoTac A-574, NeoTac 2010, NeoTac 2457, NeoTac 2465, NeoTac 5468 all from Zeneca Resins. An example of an urethane type pressure sensitive adhesive is NeoTac 560 (Zeneca Resins). Desirably the pressure sensitive adhesive will have good water resistance to ensure good adhesion when the stent and the balloon are in contact with body fluids. In addition desirably the polymeric material, of which one of lamellar sections A (5) or B (6), especially A (5) consists, is non-compliant while the other polymeric material, of which the other of lamellar sections A (5) or B (6) consists, is compliant. Possible materials could involve (hard) Nylon (polyamides) and for the more soft/compliant part certain sorts of PEBA.
Another aspect and embodiment of the current invention is directed to a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1) comprising providing at least one first polymeric-layer (4) consisting of at least one lamellar section A (5) and an equal number of lamellar sections B (6) disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member (3) with adjacent sections having a different elasticity. Desirably the elasticity may be expressed as different shore hardness, E-modulus, tensile strength, elongation at break, or compliance, but preferably is expressed as a different shore hardness.
In this embodiment of a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1) desirably the first expandable and contractible member (3) is a medical balloon. The medical balloon (3) is capable of being expanded and contracted. Desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 2 each of lamellar sections A (5) and lamellar sections B (6). Also desirably the first polymeric-layer (4) of the first expandable and contractible member (3), the medical balloon, consists of at least 3 each of lamellar sections A (5) and lamellar sections B (6). Desirably lamellar section A (5) and lamellar section B (6) consist of two different polymeric materials, especially different polymers or block-co-polymers like selected from e.g. Nylons, PEBA or mixtures thereof.
In one embodiment of a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1), desirably there is provided an additional second polymeric-layer (8) of the expandable and contractible member (3) disposed within the first polymeric layer (4). In another alternative embodiment, desirably there is provided an additional third polymeric-layer (9) disposed about the first polymeric layer (4), and in a third alternative embodiment, desirably there is provided an additional third polymeric-layer (9) of the expandable and contractible member (3) disposed about the first polymeric layer (4) and an additional second polymeric-layer (8) of the expandable and contractible member (3) disposed within the first polymeric layer (4). Desirably the second polymeric-layer (8), in another alternative embodiment, and/or the third polymeric layer (9) consists of PEBA or Nylon or mixtures thereof. Advantageously the second (or third) polymeric layer, in this embodiment, provides the strength and air tightness to the medical balloon, allowing the sections A and B to not necessarily be tightly bound to each other and also to be selected from material usually not used in a medical balloon.
In one embodiment of a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1), desirably the polymeric material, of which lamellar section A (5) or lamellar section B (6) consists, is adhesive, while the other is not, or one of lamellar section A (5) or lamellar section B (6) is layered with an adhesive (10), while the other is not. Adhesives as defined in this invention especially are mild adhesives, preferably an adhesive being pressure sensitive and selected as to release the second medical device (stent) (7) from the expandable and contractible member (3) (the medical balloon) upon pressure being applied from within the second medical device aiming at distancing the stent (7) from the adhesive (10) of the balloon. Selected pressure sensitive adhesives, include silicone type pressure sensitive adhesives, acrylic type pressure sensitive adhesives and urethane type pressure sensitive adhesives. Examples of acrylic type pressure sensitive adhesives include NeoTac A-580, NeoTac A-574, NeoTac 2010, NeoTac 2457, NeoTac 2465, NeoTac 5468 all from Zeneca Resins. An example of an urethane type pressure sensitive adhesive is NeoTac 560 (Zeneca Resins). Desirably the pressure sensitive adhesive will have good water resistance to ensure good adhesion when the stent and the balloon are in contact with body fluids. In addition desirably the polymeric material, of which one of lamellar sections A (5) or B (6), especially A (5) consists, is non-compliant while the other polymeric material, of which the other of lamellar sections A (5) or B (6) consists, is compliant. Possible materials could involve (hard) Nylon (polyamides) and for the more soft/compliant section certain sorts of PEBA.
In one further embodiment, a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1) comprises providing at least one first polymeric-layer (4) consisting of at least one lamellar section A (5) and an equal number of lamellar sections B (6) disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member (3) with adjacent sections having a different elasticity, like shore hardness, the medical device (1) is a delivery apparatus for delivering at least one second medical device (7). The expandable and contractible member (3) comprises at least one first polymeric-layer (4) consisting of at least one lamellar section A (5) and an equal number of lamellar sections B (6) disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member (3) with adjacent sections having a different elasticity, like shore hardness. Desirably, the medical device (7) is a delivery apparatus with a stent, a stent graft, a graft or a graft connector as second medical device. Very desirably, the medical device (1) is a delivery apparatus with a stent (7) as second medical device. In one embodiment, of a method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1) the delivery apparatus comprises a catheter with a medical balloon (3) as first expandable and contractible member, thus being a balloon catheter. Thereby, the second medical device, the stent (7), is disposed about the medical balloon (3) (the first expandable and contractible member). Additional details concerning the construction of suitable stent delivery apparatuses for use in the invention may be found in U.S. Pat. Nos. 6,036,697, 5,893,868 and 5,957,930 and elsewhere in the patent literature. Any suitable stent may be used whether formed of metal or of polymeric material or of another material. Examples of suitable stents may be found in U.S. Pat. Nos. 6,533,809 and 6,602,285. The Medical balloon is capable of being expanded and contracted. In this embodiment, of this method for improving the refolding behaviour of a first expandable and contractible member (3) of a medical device (1) the polymeric material, of which lamellar section A (5) or lamellar section B (6) consists, is adhesive, while the other is not, or one of lamellar section A (5) or lamellar section B (6) is layered with an adhesive (10), while the other is not. Adhesives as defined in this invention especially are mild adhesives, preferably an adhesive being pressure sensitive and selected as to release the second medical device (stent) (7) from the expandable and contractible member (3) (the medical balloon) upon pressure being applied from within the second medical device aiming at distancing the stent (7) from the adhesive (10) of the balloon. Selected pressure sensitive adhesives, include silicone type pressure sensitive adhesives, acrylic type pressure sensitive adhesives and urethane type pressure sensitive adhesives. Examples of acrylic type pressure sensitive adhesives include NeoTac A-580, NeoTac A-574, NeoTac 2010, NeoTac 2457, NeoTac 2465, NeoTac 5468 all from Zeneca Resins. An example of an urethane type pressure sensitive adhesive is NeoTac 560 (Zeneca Resins). Desirably the pressure sensitive adhesive will have good water resistance to ensure good adhesion when the stent and the balloon are in contact with body fluids. In addition, the polymeric material, of which one of lamellar sections A (5) or B (6), especially A (5) consists, is non-compliant while the other polymeric material, of which the other of lamellar sections A (5) or B (6) consists, is compliant. Possible materials could involve (hard) Nylon (polyamides) and for the more soft/compliant part certain sorts of PEBA.
Another aspect and embodiment of the current invention is directed to a method of producing a medical device according to the invention, wherein the lamellar section/s A (5) and the lamellar section/s B (6) are co-extruded, when producing the first polymeric-layer (4) of the expandable and contractible member (3).
Another aspect and embodiment of the current invention is directed to a method of producing a medical device according to the invention, wherein the lamellar section/s A (5) and the lamellar section/s B (6) of the expandable and contractible member (3) are either simultaneously or consecutively extruded onto the second polymeric-layer (8).
Another aspect and embodiment of the current invention is directed to a method of treatment of a disease, like a cardiovascular disease, especially a stenosis, using in a patient, being a mammal, especially a human, in need thereof a medical device (1) according to the invention, desirably in minimal invasive surgery like PTCA. In this, the first expandable and contractible member (3) (the Medical Balloon) comprising at least one first polymeric-layer (4) consisting of at least one lamellar section A (5) and an equal number of lamellar sections B (6) disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member (3) with adjacent sections having a different elasticity, like shore hardness, can be advantageously used, having an improved refolding behaviour allowing safe removal/movement of the medical device through a tight lumen, like a vessel.
A further aspect and embodiment of the current invention is directed to the use of a medical device (1) according to the invention for the treatment of a disease, like a cardiovascular disease, especially a stenosis, especially through minimal invasive surgery like PTCA. In this, the first expandable and contractible member (3) (the Medical Balloon) comprising at least one first polymeric-layer (4) consisting of at least one lamellar section A (5) and an equal number of lamellar sections B (6) disposed in an alternating sequence in parallel to the longitudinal axis of the expandable and contractible member (3) with adjacent sections having a different elasticity, like shore hardness, can be advantageously used, allowing safe removal/movement of the medical device through a tight lumen, like a vessel.
In this embodiment of the invention—depicted in general outlines
After positioning the expanded stent (7b) in the vascular system by inflating the balloon (3) the balloon (3) is being contracted. The lamellar sections A (5) have a higher shore hardness than the lamellar sections B (6) with a lower shore hardness. Accordingly, the sections A help the refolding of the balloon giving a scaffold to the overall structure, which on the other hand is more flexible due to the softer lamellar section B, thus avoiding the dreaded “pan-caking” upon deflation, but also avoiding “dog-boning” during inflation.
In this embodiment of the invention—depicted in general outlines
After positioning the expanded stent (7b) in the vascular system by inflating the balloon (3) the balloon (3) is being contracted. The lamellar sections A (5) have a higher shore hardness than lamellar sections B (6) with a lower shore hardness. Accordingly, the sections A help the refolding of the balloon giving a scaffold to the overall structure, which on the other hand is more flexible due to the softer lamellar section B, thus avoiding the dreaded “pan-caking”, but also “dog-boning”.
In this embodiment of the invention following closely to example 2a—depicted in general outlines
After positioning the expanded stent (7b) in the vascular system by inflating the balloon (3) the balloon (3) is being contracted. The lamellar sections A (5) have a higher shore hardness than lamellar sections B (6) with a lower shore hardness. Accordingly the sections A help the refolding of the balloon giving a scaffold to the overall structure, which on the other hand is more flexible due to the softer lamellar section B, thus avoiding the dreaded “pan-caking”, but also “dog-boning”.
In this embodiment of the invention—depicted in
In version a) with the pressure sensitive adhesive after blow molding in a blow molding form, the lamellar section A is covered with a pressure sensitive adhesive (10) selected to release the second medical device (stent) (7) from the expandable and contractible member (3) (the medical balloon) upon pressure being applied from within the second medical device aiming at distancing the stent (7) from the adhesive (10) of the balloon. Selected pressure sensitive adhesives, include silicone type pressure sensitive adhesives, acrylic type pressure sensitive adhesives and urethane type pressure sensitive adhesives. Examples of acrylic type pressure sensitive adhesives include NeoTac A-580, NeoTac A-574, NeoTac 2010, NeoTac 2457, NeoTac 2465, NeoTac 5468 all from Zeneca Resins. An example of an urethane type pressure sensitive adhesive is NeoTac 560 (Zeneca Resins). Desirably the pressure sensitive adhesive will have good water resistance to ensure good adhesion when the stent and the balloon are in contact with body fluids. The balloon is then removed and crimped and folded on a catheter, thereby especially exposing the adhesive surface (10) on lamellar section A (5).
In version b) with the soft PEBAX® the soft PEBAX® is extruded onto the lamellar section A. Following that the balloon is blown in a blow molding form. The balloon is then removed and crimped and folded on a catheter, thereby especially exposing the adhesive surface (10), the sticky soft PEBAX®, on lamellar section A (5).
In both versions a) and b) afterwards a metal stent (7) in non-extended state (7a) is then crimped onto the folded balloon (3), thereby allowing the adhesive surface (10) to adhere to the inner surface of the metal stent (7, 7a). If considered necessary the balloon catheter may then be treated with a lubricious material such as silicones or hydrogel polymers as well as PEO (Polyethylene oxide), NPG (neopentyl glycol diacrylate).
When introducing the balloon catheter into the vascular system the lubricious coating—if any—facilitates movement in the system, while the stent remains fixed on the balloon stopping it from slipping-off during advancement (e.g. over a guide wire) due to the adhesive surface (10). So in
As illustrated in
When the stent (7b) is firmly fixed in the intended position within the vascular system the balloon (3) is contracted as illustrated in
In this embodiment of the invention—depicted in FIG. 6—the medical device (1) according to the invention is a balloon catheter for stent delivery with the expandable contractible member (3) accordingly being a medical balloon. The balloon has one (first) polymeric-layer (4). The polymeric layer consists of soft PEBAX® with a low shore hardness, thus causing a high compliance of the balloon. In addition on top of the polymeric layer (4) are laminated in, at least 4 different positions in parallel to the longitudinal axis of the balloon, highly non-compliant lamellar stripes being adhesive or being covered with an adhesive (10). The adhesive preferably is pressure sensitive and selected as to release the second medical device (stent) (7) from the expandable and contractible member (3) (the medical balloon) upon pressure being applied from within the second medical device aiming at distancing the stent (7) from the adhesive (10) of the balloon. Selected pressure sensitive adhesives, include silicone type pressure sensitive adhesives, acrylic type pressure sensitive adhesives and urethane type pressure sensitive adhesives. Examples of acrylic type pressure sensitive adhesives include NeoTac A-580, NeoTac A-574, NeoTac 2010, NeoTac 2457, NeoTac 2465, NeoTac 5468 all from Zeneca Resins. An example of an urethane type pressure sensitive adhesive is NeoTac 560 (Zeneca Resins). Desirably the pressure sensitive adhesive will have good water resistance to ensure good adhesion when the stent and the balloon are in contact with body fluids.
The stripes may also be of metal with an adhesive on top.
Following that, the balloon is blown in a blow molding form. The balloon is then removed and crimped and folded on a catheter, thereby especially exposing the adhesive surface (10). Afterwards a metal stent (7) in non-extended state (7a) is then crimped onto the folded balloon (3), thereby allowing the adhesive surface (10) to adhere to the inner surface of the metal stent (7,7a). If considered necessary the balloon catheter may then be treated with a lubricious material such as silicones or hydrogel polymers as well as PEO (Polyethylene oxide), NPG (neopentyl glycol diacrylate).
When introducing the balloon catheter into the vascular system the lubricious coating—if any—facilitates movement in the system, while the stent remains fixed on the balloon stopping it from slipping-off during advancement (e.g. over a guide wire) due to the adhesive surface (10). So in
As illustrated in
When the stent (7b) is firmly fixed in the intended position within the vascular system the balloon (3) is contracted, leaving the expanded stent (7b) in place. The non-compliant adhesive stripes (10) are rigid and thus help the refolding of the balloon giving a scaffold to the (softer) compliant balloon layer (4), thus avoiding the dreaded “pan-caking”, but also “dog-boning”, while the expanded stent (7, 7a) remains in place and the adhesive parts (10) have lost their contact with the stent (7) (see as an example
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
| Number | Date | Country | Kind |
|---|---|---|---|
| 07025022.0 | Dec 2007 | EP | regional |
This application is a U.S. Nationalization of PCT Application Number PCT/EP2008/010947 filed 19 Dec. 2008, entitled “LAMELLAR SHAPED LAYERS IN MEDICAL DEVICES,” which claims the benefit of European Patent Application No. 07025022.0 filed 21 Dec. 2007, entitled “LAMELLAR SHAPED LAYERS IN MEDICAL DEVICES,” the entireties of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP08/10947 | 12/19/2008 | WO | 00 | 9/20/2010 |
