WO2015004173A1

WO2015004173A1 - Delivery system for transcatheter aortic valve implantation

Info

Publication number: WO2015004173A1
Application number: PCT/EP2014/064684
Authority: WO
Inventors: Thomas Toellner; Michael LITZENBURGER
Original assignee: Jenavalve Technology Gmbh
Priority date: 2013-07-11
Filing date: 2014-07-09
Publication date: 2015-01-15

Abstract

The present invention relates to a delivery system for transcatheter aortic valve implantation comprising a handle portion, located at a proximal end of the delivery system, and a distal tip portion (40), located at a distal end of the delivery system, the distal tip portion comprising a seating portion (50) for accommodating a heart valve prosthesis. A first catheter tube (10) extending between the handle portion and the distal tip portion (40) of the delivery system is provided, comprising a first section (11) extending distally from the handle portion, a second section (12), extending distally from the first section (11), and a third section (13), extending distally from the second section (12). In order to achieve sufficient pushability and trackability for the present delivery system, the first and third section (11, 13) of the first catheter tube (10) are configured to have a lower flexibility than the second section (12).

Description

DELIVERY SYSTEM FOR TRANSCATHETER AORTIC VALVE IMPLANTATION

Description

The present disclosure relates generally to surgery procedures and more specifically to devices and methods for minimally-invasive surgery such as minimally-invasive cardiac surgery. In more detail, some embodiments of the disclosure relate to technology pertinent to heart valve defect treatment, such as treatment of a heart valve failure or a heart valve stenosis in a patient.

The present disclosure further concerns a delivery system for transcatheter aortic valve implantation.

Heart valve surgery is used to repair or replace diseased heart valves. Medical technology has long since endeavored to correct valvular defects such as, for example, aortic valve insufficiencies or aortic valve stenosis, without requiring open heart surgery with minimally invasive methods. During the last decades minimally invasive forms of treatment have been developed and approved. They are in particular characterized in that a catheter delivery system is employed in order to advance to the side inside the body for implantation of a prosthetic device. Since by employing a catheter delivery system only small incisions are necessary resulting in a faster patient recovery with less pain and bodily trauma can be achieved. Furthermore, in particular, in the case of performing a minimal invasive heart surgery the patient should not be placed on cardiopulmonary bypass for the duration of the surgery allowing the procedure to be performed under local anesthesia. This, in turn, may reduce the medical costs and the overall disruption of the life of a patient.

The term "delivery system" as used herein generally refers to a medical system with which, for example, a stent system can be advanced in a minimally invasive fashion to the side of implantation in the patient's heart, for example to treat an aortic valve stenosis and/or aortic valve insufficiency. A delivery system thereby allows access by surgical instruments.

In the present context, "minimally invasive" implantation procedures are procedures for treating a patient where, for example, a heart-lung machine is not needed when performing the procedure on the anaesthetized patient such that the medical procedure.

The expression "heart valve stenosis and/or aortic valve insufficiency" generally refers to, for example, a congenital or acquired dysfunction of one or more cardiac valves. Such valvular disorders can affect any of the four cardiac valves, whereby the valves in the left ventricle (aortic and mitral valve) are certainly more frequently affected than thus of the right ventricle (pulmonary and tricuspid valve). The functional disorder can result in narrowing (stenosis) or inability to close (insufficiency) or a combination of the two (combined cardiac defect).

A medical delivery system may comprise a seating portion by which a stent, as needed with a prosthetic heart valve affixed thereto, can be introduced into the patient's body in its folded state. The medical delivery system can, for example, exhibit a distal tip portion having at least one manipulatable seating portion at a distal end region of the delivery system, i.e. closest to the heart.

It is moreover conceivable for the medical catheter delivery system to exhibit a handle portion at the proximal end region of the delivery system, i.e. at the end region of the delivery system furthest from the heart and the distal tip portion, by means of which the at least one seating portion of the distal tip portion can be appropriately manipulated such that an expandable stent or prosthesis

accommodated in the tip portion can be incrementally released from the catheter tip according to a predefined or predefinable sequence of events. Commonly, there is at least one first catheter tube extending between the handle portion and the distal tip portion of the delivery system. The catheter tube represents or houses a force transmitting member, which is designed to transmit the manipulating forces to the distal tip portion of the delivery system, so as to sequentially release a heart valve prosthesis from the seating portion of the distal tip portion according to a pre-definable sequence of the events.

Generally, there are two minimally invasive approaches known for implanting a prosthetic heart valve. The first approach is the so-called transapical or transventrical approach, wherein access to the heart is provided through the apical area of the heart or through a ventricle of the heart in order to introduce, for example, an expandable stent system or an expandable heart valve

prosthesis. Generally, the apical area or apex of the heart corresponds to the blunt rounded inferior extremity of the heart formed by the left and right ventricles.

Transapical or transventrical transcatheter valve implantation techniques typically involve an incision, for example, a thoracotomy, in order to gain access to the heart. After reaching the implantation side with the transapical or transventrical approach, an expandable heart valve prosthesis, for example, a stent with a prosthetic heart valve affixed thereto, can then be positioned and unfolded. After unfolding, the heart valve prosthesis can be anchored in the desired position in the heart, for example, with the aid of anchoring hubs.

The second approach is the so-called transarterial or transfemoral approach in which the delivery instrument is advanced to the implantation side via the aorta of a patient. A transarterial or transfemoral retrograde valve delivery procedure for valve replacement is typically limited by the size of the delivery system and is generally not recommended for patients with an existing peripheral vascular disease. This is because guidance of the delivery system through the patient's blood vessel can cause severe damage to the vascular walls of those vessels.

Especially the aortic arch has a significant curve which may change its direction in more than one plane. Due to this, commonly known delivery systems, which comprise a comparably fragile structure, engage significantly against the walls of the vessel into which they are introduced and can cause unnecessary trauma and distortion of the vessel. In order to reduce damage caused by the introduction of a delivery system to said vessel, it has been suggested to use delivery systems comprising a particularly high grade of flexibility. In this way, the trackability of the delivery system can be considerably improved.

The term trackability refers to the ability of a delivery system to be tracked through small tortuous vessels in order to reach the desired implantation side without causing severe damage to the vessel walls. To maximise trackability, the catheter should have a particularly flexible structure.

At the same time, however, the delivery system should have a degree of rigidity so it can be pushed from outside the patient through a patient's vasculature via the femoral artery, common iliac artery, aortic bifurcation, descending aorta and into the thoracic aorta and aortic arch. This characteristic is commonly known as pushability which refers to the ability to transmit force from the proximal end of the delivery system to the distal end. To maximise pushability, some prior art catheters incorporate a stainless steel outer tube on a proximal and distal shaft section. One limitation of such a construction is that the stainless steel outer tube is often prone to kinking.

Furthermore, the polymeric distal tip portion of the commonly known delivery systems is made from a very flexible, soft distal tip, which deforms easily when being introduced into the patient's vasculature. Although this solution

substantially decreases the risk of damaging the vessel walls, a significant deformation of the distal portion may damage a heart valve prosthesis seated therein. Also, such a deformation of the distal tip portion may cause problems in positioning of the heart valve prosthesis at the correct implantation side. This is because the orientation of the prosthetic heart valve is substantially affected by the direction of the distal tip portion.

In view of the afore-mentioned problems, it is an objective of the present invention to provide a delivery system for transcatheter aortic valve implantation which combines a high pushability, sufficient trackability and at the same time facilitates a kink-resistant distal tip portion for securely accommodating a prostethic heart valve. Another object is to provide a delivery system which, despite being flexible enough not to damage the vessel walls of the patient, allows for an easy and accurate positioning of the heart valve prosthesis at a desired implantation side.

According to one aspect of the disclosure, the invention resides in a delivery system for transcatheter aortic valve implantation comprising a handle portion located at a proximal end of the delivery system. Furthermore, the delivery system has a distal tip portion located at a distal end thereof. The distal tip portion exhibits a seating portion for accommodating a heart valve prosthesis. A first catheter tube extends between the handle portion and the distal tip portion of the delivery system. The first catheter tube is substantially divided into three different sections comprising a first section, extending distally from the handle portion, a second section, extending distally from the third section, and a third section extending distally from the second section.

In order to achieve a particularly high pushability, whilst remaining sufficient trackability and reducing the risk of kinking at the distal tip portion, the first and third section of the first catheter tube are configured to have a lower flexibility than the second section.

In this disclosure, the term "flexibility" refers to the ability of the catheter tube to adapt/bend when external forces occur. That is, the flexibility of the first catheter tube represents the ease with which the different sections of the catheter tube can be deformed, so as to adapt to potential bends in the vasculature of the a patient's body. The flexibility of the various sections of the first catheter tube can be measured by a bending/kink test. Particularly, each section may be clamped at its distal and proximal end and bend to a certain degree by applying a force to the centre of the respective section. The amount of force required to bend the respective section of the catheter tube to a predefined degree, represents a dimension of flexibility.

According to some embodiments disclosed herein, the most flexible second section of the first catheter tube is designed to be located in the aortic art region during the implantation procedure. This may guarantee an optimised localisation of the heart valve prosthesis prior to the deployment. At the same time, the more rigid first section may provide for a sufficiently high pushability of the delivery system, whereas the third section, which has a lower flexibility than the second section, guarantees the correct orientation of the heart valve prosthesis in the aortic valve region. Furthermore, the third section is particularly kink resistant and thus further increases the trackability of the inventive delivery system.

According to some embodiments disclosed herein, a distal part of the tip portion of the delivery system comprises a soft distal tip having a higher flexibility than the third section of the first catheter tube. In this way, the present delivery system substantially reduces the risk of damaging the vessel walls of a patient's musculature, during insertion. In other words, the soft distal tip portion of the delivery system may bend easily upon contacting the vessel walls, where after the resulting bending forces are transmitted to the first catheter tube, thereby increasing the trackability of the delivery system. As the third section of the first catheter tube has a lower flexibility than the soft distal tip and the second section, the bending force induced by the soft distal tip engaging the vessel wall, will be transferred to the second section, without kinking or substantially affecting the orientation of the third section.

In other aspects of the present disclosure, the third section of the catheter tube forms a proximal part of the distal tip portion. This proximal part of the tip portion is configured to cover the seating portion at least partially. In other words, the most rigid third section of the first catheter tube is designed to cover the seating portion and hence the prosthetic heart valve accommodated therein at least partially. Therefore, the third section can be used to protect the prosthetic heart valve from bending or kinking stresses. At the same time, the third section of the first catheter tube can be used to sequentially release the prosthetic heart valve accommodated in the seating portion, as will be described in more detail below.

With reference to some embodiments of the present disclosure, the first catheter tube may comprise an inner layer comprising at least one polymeric material. The inner layer could also be described as a base layer of the first catheter tube, defining an inner lumen extending there through. The inner layer may be made of any suitable polymeric material, preferably polytetrafluoroethylen (PTFE). Other examples of suitable materials include, but are not limited to, polyoxymethylene (POM), polybutylene terephthalate (PBT), polyether block ester, polyether block amide(PEBA), fluorinated ethylene propylene (FEP), polyethylene (PE),

polypropylene (PP), polyvinylchloride (PVC), polyurethane, polyether-ether ketone (PEEK), polyimide, polyamide, polyphenylene sulphide (PPS), polyphenylene oxide (PPO), polysufone, nylon, perfluoro-(propyl vinyl ether) (PFA), polyether-ester, polymer/metal composites, etc., or mixtures, blends or combinations thereof, and may also include or be made up of a lubricous polymer. One example of a suitable polyether block ester is available under the trade mark name ARNITEL, and one suitable example of a polyether block amide (PEBA) is available under the trade name PEBAX, from ATOMCHEM POLYMERS.

According to some embodiments disclosed herein, the thickness of the inner layer of the third section is thicker than the thickness of the inner layer of the first and second section of the first catheter tube. Therefore, the third section has a heavy wall inner layer, which is particularly advantageous, if the third section forms a part of the distal tip portion, as described above. In this case, the thicker inner layer of the third section prevents penetration of the first catheter tube by the struts of the heart valve prosthesis, during insertion and/or deployment.

Preferably the thinner parts of the inner layer along the first and second sections of the first catheter tube have a thickness of 0.04 to 0.06 mm. The thick inner layer of the third section of the first catheter tube, on the other hand, preferably comprises a thickness which is two or three times the thickness of the first and second sections that is about 0.08 to 0.2 mm.

According to another aspect of the aforementioned embodiment, the inner layer of the first catheter tube comprises a transition portion between the second and third section. This transition portion is configured to gradually increase the thickness of the inner layer between the second and third section. As the thickness of the inner layer increases gradually along the transition portion, a smooth variation of the level of flexibility between the second and the third second section can be achieved. Furthermore, the transition portion provides for a smooth inner surface such that rough edges inside the inner lumen of the first catheter tube are avoided. Accordingly, any second or third catheter tube may be guided within the inner lumen of the first catheter tube smoothly.

In some embodiments of the present disclosure, the first catheter tube comprises an outer layer being disposed radially around the inner layer. The outer layer may comprise at least one polymeric material. The particular polymeric material of the outer layer may substantially influence the flexibility of the first, second and third section of the first catheter tube. In principle, the polymeric material may comprise the same suitable materials as already mentioned in connection with the inner layer of the first catheter tube.

In order to obtain the different flexibilities of the first, second and third section of the first catheter tube, the outer layer may comprise a first polymeric material at the first section, a second polymeric material at the second section and third a polymeric material at third section of the first catheter tube. In one embodiment, it is preferred to apply nylon 11 or 12 as the first and third polymeric material of the stiffer first and third sections. The second polymeric material, on the other hand, is preferably made of a polyether block amide (PEBA), in order to construct the highly flexible second section of the first catheter tube. A particularly preferable kind of polyether block amide (PEBA) is available under the trade name PEBAX, from ATOMCHEM POLYMERS. Therefore, unlike common delivery systems, the first catheter tube of the inventive delivery system does not necessarily need metallic structures, so as to exhibit the a variation of the flexibility between the proximal and distal end.

With reference to the thickness of the outer layer, it should be noted that, in contrast to the inner layer, the thickness of the first and second section may be thicker than the thickness of the first section so as to obtain a more evenly distributed thickness along the first, second and third section of the first catheter tube.

In some embodiments of the delivery system disclosed herein, the second section and at least parts of the third section of the catheter tube comprise a flat wire coil, disposed between the inner and outer layer of the first catheter tube, acting as a reinforcement member. Particularly the second and third section of the first catheter tube are exposed to strong bending forces, which may lead to kinking of said second and third sections. Due to the existence of a flat wire coil, however, the first catheter tube of the delivery system has a non-kinkable design in the region of sharp bends, like the aortic arch and the implantation side (e.g. aortic valve region). The flat wire coil may cover the whole of the second section and only parts of the third section. As will be described in more detail below, this is because the third section may comprise a marker band for tracking the position of the delivery system within the patient's body. In addition to or as an alternative to the flat wire coil, the first, second and third section of the first catheter tube may comprise a flat wire braid disposed between the inner and outer layer of the first catheter tube. The flat wire braid may provide for the first catheter tube to have a low overall elongation due to compressive loads acting on the catheter tube. In particular, the flat wire braid shall be constructed in such a way that an elongation limit of 2 mm under a specific load of 20 N is not exceeded for the complete length of the first catheter tube.

In order to optimise the flexibility distribution of the first catheter tube of the delivery system according to the present invention, the flat wire braid of the third section preferably has a denser structure than the flat wire braid of the first and second sections of the first catheter tube. Furthermore, the flat wire braid of the second section may have a denser structure than the flat wire braid than the first structure of the first catheter tube. In particular, the flat wire braid of the third section may have a structure which is three times denser than the structure of the flat wire braid of the second section. The second section, in turn, may have a flat wire braid with a structure, which is two times denser than the structure of the flat wire braid of the third section. The density of the flat wire braid may be measured in "picks-per-inch", which relates to the number of wire filaments crossing per inch of the flat wire braid. That is, a higher number of picks-per-inch corresponds to a denser flat wire braid. Preferably, the inventive delivery system may have a first catheter tube with a flat wire braid having 10 picks-per-inch at the first section, 20 picks-per-inch at the second section and 60 picks-per-inch at the third section of the first catheter tube.

According to one aspect of the delivery system disclosed herein, the third section of the first catheter tube comprises an x-ray marker band disposed between the inner and outer layer of the first catheter tube. In this way, the first catheter tube does not only provide for a high pushability and trackibility of the delivery system, but also allows targeting the position of the delivery system within a patient's vasculature. The marker band may be disposed at a distal end of the third section. Preferably, the marker band is disposed over the flat wire braid of the third section. At the position of the marker band, it is preferred not to arrange a flat wire coil, as this may influence the visibility of the marker band. The marker band may be made of any suitable material, for example Platinum (Pt), being 0.4 to 0.8 mm broad and having a thickness of 0.1 to 0.2 mm.

In another embodiment, the first and second sections of the first catheter tube comprise a tie layer disposed between the inner and outer layer of the first catheter tube. In particular, the tie layer may be disposed on an outer surface of the inner layer so as to reduce a partial elongation of the first and second sections of the first catheter tube. The tie layer may be made of a nylon 12 material or any other suitable polymer and may be disposed directly on the outer surface of the inner layer. That is to say, the tie layer is preferably disposed between the inner layer and the flat wire coil or the flat wire braid respectively.

In order to increase trackability of the inventive delivery system, the first catheter tube may comprise a surface coating layer disposed on an outer surface of the outer layer. In more detail, this surface coating layer functions as a slipping surface, which reduces the friction between the outer surface of the outer layer and the patient's vessel walls. The outer layer is preferentially made of a hydrophobic polymer such as P-xylene which is commonly known as parylene, being chemically resistant with good barrier properties for inorganic and organic media. Alternatively, the outer layer may be made from a hydrophilic polymer such as Kollidon. The surface coating may have a thickness of 2 pm to 5 pm, and more preferably 3 μιτι.

As already indicated, in some embodiments disclosed herein, the first catheter tube of the delivery system may comprise an inner hollow lumen inside of the inner liner of the first catheter tube.

In one embodiment, the inner lumen of the first catheter tube comprises a first inner diameter along the first and second section of the catheter tube and a second inner diameter along the third section, wherein the second inner diameter is bigger than the first inner diameter. In other words, according to this aspect, the diameter of the inner lumen of the first catheter tube expands between the second and third section, i.e. toward the distal end of the catheter tube. In this case, the first catheter tube comprises a taper section, extending between the second and third section of catheter tube so as to gradually increase the diameter there between. Because of the taper section, the outer surface of the first catheter tube does not exhibit any rough edges, which could lead to damage along the vessel walls during insertion.

The aforementioned embodiment may comprise a first and second inner diameter is particularly useful, if the first section of the catheter tube forms a part of the distal tip portion, as described above. In this way, only the third section may have an increased diameter so as to cover the prosthetic heart valve which is accommodated on the seating portion of the distal tip portion. The remaining parts of the first catheter tube, however, may exhibit, a smaller diameter which increases the precision and safety when using the inventive delivery system. Of course, it is also feasible to form all of the different sections of the first catheter tube with a constant inner diameter.

In the following, an exemplary embodiment of the present delivery system will be described in more detail.

Fig. 1 : illustrates an exemplary embodiment of the distal tip portion a

delivery system according to the present invention;

Fig. 2: illustrates schematically a cross-sectional view of an exemplary

embodiment of a catheter arrangement of a delivery system for retrograde insertion of expandable heart valve prosthesis;

Fig. 3: illustrates a cross-sectional side view of a first catheter tube of a delivery system according to the present invention; and

Fig. 4a - 4c: illustrate enlarged views of the third and second section of the first catheter tube of a delivery system according to the present invention.

The present invention relates to a delivery system for transcatheter, particularly retrograde, aortic valve implantation. The delivery system comprises a handle portion (not shown) located at a proximal end of the delivery system as well as a distal tip portion 40 located at a distal end of the delivery system. An exemplary embodiment of the distal tip portion 40 of the delivery system having prosthesis retaining elements 45 is described below with reference to Fig. 1. In more detail, Fig. 1 illustrates schematically an exemplary embodiment of a distal tip portion 40 of a medical catheter delivery system for retrograde insertion of an expandable heart valve prosthesis in a part-sectioned side elevation. The heart valve prosthesis could be inserted into the body of a patient by way of the exemplary embodiment of the distal tip portion 40 illustrated in Fig. 1.

In the exemplary embodiment depicted in Fig. 1, the distal tip portion 40 has a seating portion 50 for accommodating a heart valve prosthesis (not shown) to be inserted in its collapsed state. Furthermore, the distal tip portion 40 is provided with a stent retaining element 45 for releasably fixing the heart valve prosthesis to the seating portion of the distal tip portion 40. In the embodiment illustrated in Fig. 1, the stent retaining element 45 comprises a crown having attachment elements 46 for releasably connecting with specific retaining elements of the heart valve prosthesis to be implanted. Hence, the stent retaining element 45 of the distal tip portion 40 functionally serves as a "stent holder".

In accordance with some aspects of the present disclosure, the seating portion of the distal tip portion 40 is constituted by at least one sleeve shaped member 41, 42. In the embodiment illustrated in Fig. 1, the seating portion of the distal tip portion 40 comprises a total of two sleeve-shaped members: A first sleeve- shaped member 41 and a second sleeve-shaped member 42. As shown, the respective cross sections of the two sleeve-shaped members 41, 42 are preferably chosen in such a way that the first sleeve-shaped member 41 has a slightly larger diameter than the second sleeve-shaped member 42 so that the first sleeve-shaped member 41 may cover the second sleeve-shaped member 42 at least partially, in order to completely enclose a heart valve prosthesis accommodated in the distal tip portion.

As will be described in more detail below, it is particularly preferred to construct the delivery system in such a way that a third section 13 of the first catheter tube 10 forms a proximal part of the distal tip portion 40, wherein the proximal part is configured to cover the seating portion at least partially. In simple terms, it is preferred, to use the third section 13 of the first catheter tube 10 as the aforementioned first sleeve-shaped member 41.

For releasing a heart valve prosthesis, accommodated in the seating portion of the distal tip portion, the first and second sleeve-shaped members 41, 42 are moveable relatively to each other and also relatively to the stent retaining element 45 (stent holder) used for releasably fixing a heart valve prosthesis to the distal tip portion 40.

For this purpose, the first catheter tube 10 is used as a first force transmitting member having a distal end portion (taper portion 15) connected to the first sleeve-shaped member 41 (third section 13). The first catheter tube 10, being formed as a force transmitting member, has a proximal end portion (first portion 11, Fig. 3) opposite the third section 13. The first section 11 at the proximal end of the first catheter tube 10 is operatively connected to a sliding member of the handle portion (not shown) of the inventive delivery system. Therefore, the sliding member of the handle portion can be used for manipulating the position of the first catheter tube 10 and hence to move the first sleeve-shaped member 41 of the distal tip portion 40 illustrated in Fig. 1.

In addition, a second force transmitting member having a distal end portion connected to the second sleeve-shaped member 42 is provided. The second force transmitting member is allocated to the second sleeve-shaped member 42 of the distal tip portion 40 and has a proximal end portion opposite to the distal end portion, the proximal end portion being operatively connected to a corresponding (second) sliding member (not shown) of the handle portion. In the exemplary embodiment of Fig. 1, the second force transmitting member is shown as a second catheter tube 20 which is movably located inside a first inner lumen of the first catheter tube 10. The second catheter tube 20 is connected to a soft distal tip 44 of the distal tip portion 40, which is in turn connected to the sleeve-shaped member 42. That is to say, if the second catheter tube 20 is pushed distally by means of the second sliding member of the handle portion, the second sleeve- shaped member 42 is displaced distally, together with the soft distal tip 44.

When manipulating the respective sliding member of the handle portion, the first and/or second sleeve-shaped members 41, 42 may be moved relatively to each other and relatively to the stent retaining element 45 (stent holder) of the distal tip portion 40. In this way, a heart valve prosthesis, located at the seating portion of the delivery system, can be released sequentially.

Fig. 2 illustrates schematically a cross-sectional view of an exemplary

embodiment of a catheter shaft 1 of the medical delivery system deducted for retrograde (for example transarterial, transfemoral or transubclavian) insertion of a heart valve prosthesis. According to the present invention, such a catheter shaft 1 may extend between the handle portion and the distal tip portion of the delivery system.

As can be seen from Fig. 2, the first force transmitting member allocated to the first sleeve-shaped member 41 of the distal tip portion 40 and operatively connected with a first sliding member of the handle portion may be constituted by the first catheter tube 10, defining a first lumen. The second force

transmitting member allocated to the second sleeve-shaped member 42 of the distal tip portion 40 and operatively connected with a second sliding member of the handle portion may be constituted by a further second catheter tube 20 defining a second lumen. In the exemplary embodiment in Fig. 2, the second catheter tube 20 has a cross-sectional diameter which is less than the cross- sectional diameter of the first catheter tube 10. The first catheter tube 10 is disposed concentrically and coaxially with the second catheter tube 20 and the second catheter tube 20 is received within the first lumen defined by the first catheter tube 10.

Contrary to the first and second sleeve shaped members 41, 42 of the distal tip portion 40, however, the stent retaining element 45 (stent holder, Fig. 1) of the distal tip portion 40 is preferably not axially movable relatively to the handle portion of the delivery system. Rather, the stent retaining element 45 is connected to an anchorage of the handle portion, by using a further third catheter tube 30 having a distal end portion connected to the stent retaining element 45 and a proximal end portion fixedly connected to the anchorage of the handle portion.

Referring again to the exemplary embodiment depicted in Fig. 2, the third catheter tube 30 may have a cross-sectional diameter, which is less than the cross-sectional diameter of the first catheter tube 10. In particular, the first catheter tube 10 may be disposed concentrically and coaxially with both, the third catheter tube 30, on the one hand, and the second catheter tube 20, on the other hand. Preferably, the third catheter tube 30 has a cross-sectional diameter which is less than the cross-sectional diameter of the first catheter tube 90 and greater than the cross-sectional diameter of the second catheter tube 20 such that the third catheter tube 30 is received within the first lumen defined by the first catheter tube 10. The second catheter tube 20 is preferably received within a third lumen defined by the third catheter tube 30.

In the exemplary embodiment schematically illustrated in Fig. 2, the lumen defined by the third catheter tube 30 has a diameter sufficient to accommodate the second catheter tube 20 such that the second catheter tube 20 is movable relative to the third catheter tube 30.

The second lumen defined by the second catheter tube 20 has preferably a diameter sufficient to accommodate a guide wire 180. Referring back to the exemplary embodiment of Fig. 1, it can be seen a distal end portion of the second catheter tube 20 terminates in a soft distal tip 44 which preferably has an atraumatic shape and texture. The soft distal tip 44 is provided with a channel aligned with the second lumen defined by the second catheter tube 20 such that the guide wire 180, accommodated within the second lumen, may pass through the channel of the soft distal tip 44.

As already mentioned above, the second sleeve-shaped member 42 of the catheter tip 40 is connected to the soft distal tip 44 such that the open end of the second sleeve-shaped member 42 faces in the proximal direction opposite to the direction of the soft distal tip 44, i.e. in the direction of the handle portion of the delivery system.

With reference to Figs. 3 and 4a-c the first catheter tube 10 shall be described in more detail. In the embodiment depicted by Fig. 3, the first catheter tube 10 is divided into several sections along its longitudinal axis. In particular, the first catheter tube 10 comprises at least a first section 11 extending distally from the handle portion (not shown), a second section 12, extending distally from the first section 11, and a third section 13 extending distally from the second section 12. In addition, the first catheter tube 10 comprises a taper section 15, extending between the second and third section 12, 13 of the first catheter tube 10. The taper section 15 is adapted to gradually increase the diameter between the second and third section 12, 13 of the first catheter tube 10.

Referring back to the cross-sectional view of Fig. 2, it can be seen that the third section may be formed with a larger inner diameter to adapt the distal part of the first catheter tube 10 to the diameter of the distal tip portion 40 of the delivery system. In other words, the third section 13 has an enlarged diameter, so as to cover the seating portion of the distal tip portion 40. Accordingly, the third section 13 of the first catheter tube 10 can be used to form a proximal part of the distal tip portion 40, namely the first sleeve-shaped member 42, which may cover a heart valve prosthesis accommodated in the seating portion (not shown).

In order to maximise the pushability and trackability of the present delivery system, the first and third sections 11, 13 of the first catheter tube 10 are configured to have a lower flexibility than the second section 12. Such different flexibility properties may be achieved by implementing several layers of different polymeric materials and/or reinforcement members for each of the first, second and third sections 11, 12 and 13 of the first catheter tube 10.

In the embodiment depicted in Fig. 3, the first catheter tube 10 comprises at least one inner layer 111, 121, 131, 151 defining the first hollow lumen inside the first catheter tube 10. Furthermore, the catheter tube 10 comprises at least one outer layer 112, 122, 132, 152 which is disposed radially around the inner layer 111, 121, 131, 151. The inner and outer layers each consist of at least one polymeric material.

The inner layer 111, 121, 131, 151 of the first catheter tube 10 in the

embodiment of Fig. 3 has a varying thickness along the longitudinal axis of the first catheter tube 10. In detail, the thickness of the inner layer 131 of the third section 13 is thicker than the thickness of the inner layer 111, 121 of the first and second section 11, 12 of the first catheter tube 10. In a preferred

embodiment, the thickness of the inner layer 131 of the third section 13 has a thickness of 0.08 to 0.12 mm, whereas the thickness of the inner layer of the first and second section 11 and 12 is preferably about 0.04 to 0.06 mm. A thick inner layer 131 at the third section 13 is particularly useful to avoid penetration by struts of the heart valve prosthesis accommodated within the seating portion, which is covered by the third section 13 of the catheter tube 10.

According to another aspect, the inner layer 151 of the taper section 15 may be constructed in such a way that the thickness of the inner layer increases gradually between the second section 12 and third section 13 of the first catheter tube 10. In this way, a smooth inner surface of the first catheter tube 10 can be achieved, avoiding rough edges which could hinder the movement of the second and third catheter tube 20 and 30 (Figs. 1 and 2) inside the first inner lumen of the first catheter tube 10. The inner layer 111, 121, 131, 151 of all sections 11, 12, 13, 15 of the first catheter tube preferably consists of polytetrafluoroethylene (PTFE).

With regard to the outer layer, it should be noted that the first, second and third sections 11, 12, 13 of the first catheter tube 10 preferably comprise a different polymeric materials in order to form the respective first, second and third outer layers 112, 122 and 132. In particular, the polymeric material used for the first and third outer layers 112, 132 of the first and third sections 112, 132 may be more rigid than the polymeric material implemented for the second outer layer 122 of the second section 12. Specifically, the outer layer 132 of the third section may consist of a nylon 12 material, whereas the outer layer 112, 122 of the first and second sections 11, 12 may be made of a polyether block amid (PEBA). In particular, the outer layer 112 of the first section may consist of a polyether block amid which is available under the trademark name PEBAX, from ATOMCHEM POLYMERS, having a duromere hardness of 72D. The outer layer 122 of the second section 12, on the other hand, is preferably made of a PEBAX polymer having a duromere hardness of 45D. In this way, the particular variation in flexibility along the first catheter tube 10 can be adjusted easily.

In order to prevent kinking along the second, third and the taper section 12, 13, 15, a flat wire coil 125, 135, 155 is preferably disposed between the inner and outer layer to form a reinforced section. In order to meet the flexibility

requirements, the distance between individual loops of the wire coil may be smaller at the second section 12 than at the third section 13 of the first catheter tube 10.

A more detailed view of some parts of the third section 13, which are encircled in Fig. 3, can be derived from Fig. 4a and Fig. 4b. Particularly referring to Fig. 4a, the distal end section of the first catheter tube 10 is illustrated. As can be seen, the distal part 13-1 of the third section 13 of the catheter tube 10 does not comprise a flat wire coil. Instead, the distal end section comprises an x-ray marker band 138, which is disposed between the inner and outer layers 131, 132 of the first catheter tube 10. A more proximal part 13-2 of the third section 13 is shown in Fig. 4b. In contrast to the distal part 13-1 of the third section 13, the proximal part 13-2 of the third section 13 comprises a flat wire coil 135, which is disposed between the inner layer 131 and the other layer 132. Preferably, the flat wire coil 135 extends from the proximal part 13-2 of the third section 13 back into a proximal direction and entirely covers the inner layer 151, 121 of the taper section 15 and the second section 12. Because of the flat wire coil 155 located along the inner layer 151 of the taper section 15, a gradual increase of the stiffness between the second and third section 12, 13 of the first catheter tube 10 can be achieved. Therefore, kinking along the taper section 15 of the first catheter tube 10 can be avoided efficiently.

Figs. 3 and 4a to 4c further show that, according to the illustrated embodiment of the deliver system, a flat wire braid 113, 123, 133, 153 is disposed between the inner and outer layer of the first catheter tube 10 along the first, second, third and the taper section 11, 12, 13, 15 of the catheter tube 10. The flat wire braid 113, 123, 133, 153 of the different sections 11, 12, 13, 15 of the first catheter tube 10 provides for a particularly low overall elongation of the first catheter tube 10, which may occur due to longitudinal stresses during insertion. Moreover, the flat wire braid 113, 123, 133, 153 preferably has a varying density over the length of the first catheter tube 10. In more detail, the flat wire braid 133 of the third section 13 has a denser structure than the flat wire braid 113, 123 of the first and second section 11, 12 of the first catheter tube 10. Furthermore, the flat wire braid 123 of the second section 12 has a denser structure than the flat wire braid 113 of the first section 11. The density of the structure of the flat wire braid 153 along the taper section 15 is substantially the same as the density of the flat wire braid 123 of the second section 12.

According to a specific example, the flat wire braid 133 of the third section 13 may have a density of 60 picks-per-inch (number of braid wire filaments crossing per inch of the wire braid), whereas the taper and second sections 12, 15 may comprise a density of 20 picks-per-inch and the first wire braid 113 of the first section 11 may be formed with a density of 10 picks-per-inch.

According to the embodiment shown in Fig. 4c, the first and second section 11, 12 of the first catheter tube 10 preferably comprise a tie layer 117, 127 disposed between the inner and outer layer of the first catheter tube 10. The tie layer 117, 127 (Fig. 3) is disposed directly on the outer surface of the inner layer 111 or 121 respectively. The tie layer 117, 127 reliably couples the inner layer 111, 121 to the reinforcement members (flat wire braid, flat wire coil) and the outer layer 112, 122, thus reduces the possibility of partial elongation of individual parts of the catheter tube 10, upon insertion of the inventive delivery system. Similar to the outer layer 132 of the third section 13, the tie layer 117, 127 of the first and second section 11, 12 of the first catheter tube 10 may be made of nylon 11 or 12 polymeric material.

It should be noted, that all the polymeric materials implemented in the

construction of the first catheter tube 10 are preferably made of transparent materials, so that the first inner lumen of the first catheter tube 10 is visible. Furthermore, the first catheter tube preferably comprises a surface coating layer (not shown) disposed on an outer surface of the outer layer 112, 122, 132, 152, which may consist of a hydrophobic polymere (e.g. parylene) or a hydrophilic polymere (e.g. Kollidon) respectively.

The solution in accordance with the disclosure is not limited to the embodiment described in the attached drawings. It is contemplated that combinations of the individual features described in detail are also possible. In particular, it should be noted that the present delivery system is not limited to an application for transcatheter transplantation of an aortic heart valve, but may be used for replacement procedures of any other heart valve, like the mitral or tricuspid heart valves.

List of references catheter shaft

first tube catheter

first section

second section

third section

taper section

second catheter tube third catheter tube

distal tip portion

first sleeve-shaped member second sleeve-shaped member soft distal tip

stent retaining element attachment elements seating portion

, 121, 141, 151 inner layer

, 122, 131, 152 outer layer

, 123, 133, 153 flat wire braid

, 127 tie layer

, 135, 155 flat wire coil

x-ray marker band

guide wire

Claims

f ^EISSINER BOLTE Postfach 102605 86016 Augsburg JenaValve Technology GmbH July 7, 2014 Guerickestrasse 25 M/JEC-068-PC 80805 Miinchen TR/HF DELIVERY SYSTEM FOR TRANSCATHETER AORTIC VALVE IMPLANTATION Claims

1. Delivery system for transcatheter aortic valve implantation, comprising :

- a handle portion located at a proximal end of the delivery system;

- a distal tip portion (40) located at a distal end of the delivery system, the distal tip portion comprising a seating portion (50) for

accommodating a heart valve prosthesis;

- a first catheter tube (10) extending between the handle portion and the distal tip portion (40) of the delivery system, said first catheter tube

(10) comprising a first section (11) extending distally from the handle portion, a second section (12), extending distally from the first section

(11) , and a third section (13), extending distally from the second section (12),

c h a r a c t e r i z e d i n that,

the first and third sections (11, 13) of the first catheter tube (10) are configured to have a lower flexibility than the second section (12).

2. Delivery system according to claim 1,

wherein a distal part of the distal tip portion (40) comprises a soft distal tip (44) having a higher flexibility than the third section (13) of the first catheter tube (10).

3. Delivery system according to claim 1 or 2,

wherein the third section (13) of the first catheter tube (10) forms a proximal part of the distal tip portion (40), said proximal part being configured to cover the seating portion (50) at least partially.

4. Delivery system according to any of the preceding claims,

wherein the first catheter tube (10) comprises an inner layer (111, 121,

131, 151) comprising at least one polymeric material.

5. Delivery system according to claim 4,

wherein a thickness of the inner layer (131) of the third section (13) is thicker than the thickness of the inner layer (111, 121) of the first and second section (11, 12) of the first catheter tube (10).

6. Delivery system according to claim 5,

wherein the inner layer of the first catheter tube (10) comprises a transition portion (151) between the second and third section (12, 13), said transition portion (151) being configured to gradually increase the thickness of the inner layer between the second and the third section (12, 13).

7. Delivery system according to any of claims 4 to 6,

wherein the inner layer (111, 121, 131, 151) of the first catheter tube (10) consists of Polytetrafluoroethylene.

8. Delivery system according to any of claims 4 to 7,

wherein the first catheter tube (10) comprises an outer layer (112, 122,

132, 152) being disposed radially around the inner layer (111, 121, 131, 151), said outer layer (112, 122, 132, 152) comprising at least one polymeric material.

9. Delivery system according to claim 8,

wherein the outer layer (112, 122, 132, 152) comprises a first polymeric material at the first section (11), a second polymeric material at the second section (12), and a third polymeric material at the third section (13) of the first catheter tube (10).

10. Delivery system according to claim 9,

wherein the third polymeric material of the third section (13) is a nylon 11 or nylon 12, and wherein the first and second materials of the first and second sections (11, 12) is a polyether block amide.

11. Delivery system according to any of claims 8 to 10,

wherein the second section (12) and at least parts of the third section (13) of the first catheter tube (10) comprise a flat wire coil (125, 135, 155), disposed between the inner and outer layer (121, 122, 131, 132, 151, 152) of the first catheter tube (10).

12. Delivery system according to any of claims 8 to 11,

wherein the first, second and third section (11, 12, 13) of the first catheter tube (10) comprise a flat wire braid (113, 123, 133, 153) disposed between the inner and outer layer (111, 112, 121, 122, 131, 132, 151, 152) of the first catheter tube (10).

13. Delivery system according to claim 12,

wherein the flat wire braid (133) of the third section (13) has a denser structure than the flat wire braid (113, 123) of the first and second section (11, 12) of the first catheter tube (10).

14. Delivery system according to claim 12 or 13,

wherein the flat wire braid (113, 123, 133, 153) of the third section (13) has a structure which is three times denser than the structure of the flat wire braid (113, 123, 133, 153) of the second section (12).

15. Delivery system according to any of claims 12 to 14,

wherein the flat wire braid (113, 123, 133, 153) of the second section (12) has a denser structure than the flat wire braid (113, 123, 133, 153) of the first structure of the first catheter tube (10).

16. Delivery system according to any of claims 8 to 15,

wherein the third section (13) of the first catheter tube (10) comprises an x-ray marker band (138) disposed between the inner and outer layer (111, 112, 121, 122, 131, 132, 151, 152) of the first catheter tube (10).

17. Delivery system according to claim 16,

wherein the marker band (138) consists of Platinum or Platinum-Iridium alloy.

18. Delivery system according to any of claims 8 to 17,

wherein the first and second section (11, 12) of the first catheter tube (10) comprise a tie layer (117, 127) disposed between the inner and outer layer (111, 112, 121, 122) of the first catheter tube (10).

19. Delivery system according to claim 18,

wherein the tie layer (117, 127) is made of nylon 12.

20. Delivery system according to any of claims 8 to 19,

wherein the first catheter tube (10) comprises a surface coating layer disposed on an outer surface of the outer layer (112, 122, 132, 152).

21. Delivery system according to any of the preceding claims,

wherein the first catheter tube (10) comprises a first inner diameter along the first and second section (11, 12) of the catheter tube and a second inner diameter along the third section (13), the second inner diameter being bigger than the first inner diameter, wherein the first catheter tube (10) comprises a taper section (15), extending between the second and third section (12, 13) of the catheter tube.