Device for treating a blood vessel and associated treatment kit

A tubular endoprosthesis can be radially deployed between a retracted state and an expanded state. It includes an axially rigid support which has at least one retention opening. The device further includes at least one filamentary connection which has a region for clamping the endoprosthesis, at least partially surrounding the endoprosthesis, and a control region which is connected to the clamping region via the retention opening. The support is permanently fixed to the endoprosthesis.

TECHNICAL FIELD

The present invention relates to a device for treating a blood circulation canal, of the type including a tubular endoprosthesis which can be radially deployed between a retracted state and an expanded state; an axially rigid support which has at least one retention opening; and at least one filamentary connection. The connection comprises a region for clamping the endoprosthesis, at least partially surrounding the endoprosthesis, and a control region which is connected to the clamping region via the retention opening.

A device of this type is used in particular for releasing, in a blood vessel, tubular endoprostheses, commonly referred to as “stents”, or tubular endovalves which comprise a tubular endoprosthesis and a valve which is fixed to the endoprosthesis.

BACKGROUND TO THE INVENTION

A device of the above-mentioned type is described in EP-A-0 707 462. An endoprosthesis is mounted coaxially on two hollow tubes which are capable of sliding relative to each other. This endoprosthesis is retained in the retracted state thereof by two filamentary connections which surround it at the ends thereof. The filamentary connections are engaged in distal and proximal retention openings which are arranged in one support and the other, respectively.

In order to release the endoprosthesis, the supports are displaced by relative sliding in a first direction in order to release the filamentary connections and simultaneously deploy the two ends of the endoprosthesis. If the positioning of the endoprosthesis is not satisfactory, the filamentary connections can be tightened by sliding the supports in the opposite direction, which brings about the contraction of the endoprosthesis.

When the positioning of the endoprosthesis is satisfactory, the filamentary connections are removed.

A device of this type is not entirely satisfactory. This system has a complex structure which may compromise the reliability of the release operation.

SUMMARY OF THE INVENTION

The object of the invention is to provide a device for treating a blood vessel which can be released in a reversible manner in a blood vessel, without the reliability thereof being reduced.

To this end, the invention relates to a treatment device of the above-mentioned type, wherein the support is permanently fixed to the endoprosthesis.

The device according to the invention may comprise one or more of the following features, taken in isolation or according to any technically possible combination. The endoprosthesis can have a peripheral wall, the support being fixed at least at two points which are axially spaced from the peripheral wall. The peripheral wall can delimit internally a channel for passage of a fluid, the support being fixed to the peripheral wall at the outer side of the passage channel. The support can extend axially substantially over the entire length of the endoprosthesis. The support can delimit internally an aperture which opens in the or each passage opening and in at least one control opening which is spaced longitudinally from the or each passage opening. The or each filamentary connection can have a gripping end which protrudes from the support through the control opening, the gripping end forming a traction loop. The control region can include two strands which are connected to the traction loop and to two separate points of the clamping region. The endoprosthesis can include at least two filamentary connections which comprise two clamping regions which are axially spaced on the endoprosthesis. The gripping ends of the two connections from a traction loop common to the two connections. The endoprosthesis can include at least two filamentary connections, the support delimiting a proximal control opening and a distal control opening. The gripping ends of the two connections protrude through the proximal control opening and the distal control opening, respectively. The traction loop can include a ring which is fixedly joined to the control region, the ring having a transverse extent which is greater than that of the control opening. At least one filamentary connection can be releasable.

The invention further relates to a treatment kit, of the type including a device as defined above. In addition, the kit includes a means for releasing and/or recovering the device. The means includes a rigid rod which has a distal support surface for the device; and a means for traction of the or each filamentary connection which are capable of gripping the or each control region.

The treatment kit may also include the following features. The or each filamentary connection can have a gripping end which forms a traction loop. The traction means can include, for engaging the gripping end, an elongated hook member which is mounted so as to be able to be moved in the rigid rod between a deployed position for engagement of the gripping end and a retracted position for traction of the gripping end.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 4illustrate a first kit10according to the invention, comprising a treatment device12which is intended to be released in a blood circulation canal, and a positioning member14for releasing and recovering the device12.

As illustrated inFIG. 1, the device12comprises a tubular endoprosthesis16having an axis X-X′, an axially rigid support18which is permanently fixed to the endoprosthesis16, and two filamentary connections20A,20B which at least partially surround the endoprosthesis16in the region of the proximal and distal ends thereof.

The endoprosthesis16comprises in a known manner a tubular trellis of stainless steel which has spring-like properties.

This endoprosthesis is, for example, produced by braiding a single thread of a super-resilient material as described in the European patent application EP-A-0 857 471.

The tubular trellis delimits, at the ends of the endoprosthesis16, a plurality of interlocking elbow-like joints.

The tubular trellis forms a peripheral wall22which internally delimits a channel24having an axis X-X′. The trellis is, for example, embedded in a flexible elastomer film in order to produce a sealed wall around the channel24.

As known per se, the endoprosthesis16is capable of deforming spontaneously from a retracted state illustrated inFIG. 2, in which it has a small diameter, into an expanded state illustrated inFIG. 1, in which it has a larger diameter. This expanded state constitutes the rest state thereof.

The support18comprises a hollow post member26which extends axially and which is fixed in at least two points which are axially spaced at the outer side of the peripheral wall22.

In the example illustrated, the post member26is fixed continuously to the peripheral wall22along a directrix of the peripheral wall22.

As illustrated inFIG. 3, the post member26internally delimits a central aperture27which extends axially and which opens at the ends thereof via a proximal axial control opening28and a distal axial control opening30.

The post member26delimits, in the region of the proximal opening28and the distal opening30, respectively, a transverse proximal retention opening32and a transverse distal retention opening34, through which the proximal connection20A and the distal connection20B are engaged, respectively.

The support18further delimits, around the proximal control opening28, an annular surface36for supporting the positioning member14.

Each retention thread20A,20B comprises a clamping region38A,38B which forms a loop which surrounds the endoprosthesis in the region of one of the ends thereof, and at least one control region40A,40B which is arranged in the support18and which has a proximal gripping end which protrudes through the proximal control opening28and beyond the proximal end of the endoprosthesis even in the expanded state of the endoprothesis, as shown inFIGS. 1 and 3. The gripping ends are fixed to a traction loop42which is common to the connections20A,20D.

The clamping region38A,38B is formed by a single strand of thread arranged around a circumference of the endoprosthesis16.

In a variant, the clamping region may be engaged in the trellis of the endoprosthesis16, moving successively inside and outside the trellis.

Each control region40A,40B is formed by two strands of thread which are connected to two ends of an associated clamping region38A,38B, respectively, via a corresponding retention opening32,34. The strands extend substantially axially in the passage27as far as the traction loop42to which they are fixed.

The traction loop42comprises a ring which has a transverse extent (outer diameter) greater than the transverse extent (inner diameter) of the proximal control opening28. The ring is produced from a radio-opaque material.

A traction of the ring42in a proximal direction allows the length of the control regions40A,40B of the connections20A,20B to be simultaneously increased, whilst reducing the length of the clamping regions38A,38B which thus brings about the contraction of the endoprosthesis16as will be described below.

The positioning member14for releasing and recovering the endoprosthesis16includes a rigid hollow rod50and, for catching of the loop42, an elongated hook member52which is mounted so as to be able to move along the rod50in a central passage54which is provided in the rod50.

The rigid rod50extends between a proximal end (not illustrated) which is intended to be accessible to a surgeon, and a distal end56which is intended to be placed in the blood canal to be treated.

The distal end56has an annular support surface58for the support18, delimiting an opening60for passage of the elongate hook member52in which the central passage54opens.

The elongate hook member52has a head62in the form of a hook. The elongate hook member52can be moved between a deployed position in which the head62protrudes from the distal end56and a retracted position for retracting of the loop42in which the head62is arranged inside the central passage54.

In order to release the device12in a vessel, the positioning member14further comprises an outer sheath70which internally receives the device12in the retracted state thereof and the rigid rod50provided with the elongate hook member52.

The operation of the first treatment kit10according to the invention will now be described. Initially, the kit10is stored in a sterile packaging. In this packaging, the endoprosthesis16is maintained in the rest state in the expanded state thereof. The clamping regions38A,38B of the connections20A,20B of the endoprosthesis have a maximum length and the control regions40A,40B have a minimal length. The traction loop42is positioned in the vicinity of the proximal control opening28whilst being retained with spacing from this opening28in order to retain the filamentary connections20A,20B in a slack state.

When the surgeon wishes to place the endoprosthesis16in the sheath70, he inserts the hook62at the end of the elongated hook member52in the traction loop42. Then, he moves the support surface58of the rigid rod50towards the annular support surface36of the post member26.

Then, when the support surfaces36and58are in contact, he moves the elongate hook member52towards the retracted position thereof which pulls the traction loop42towards the proximal end of the rigid rod50.

Since the annular surface36is arranged so as to be supported on the annular surface58, the post member26and the endoprosthesis16which is fixedly joined (permanently fixed) to the post member remain axially fixed to the distal end56of the rigid rod50.

The proximal displacement of the traction loop42brings about an increase of the length of the control regions40A,40B of the connections20A,20B and a corresponding reduction of the length of the clamping regions38A,38B.

The endoprosthesis16is thus brought into the retracted state thereof by the filamentary connections20A,20B. The assembly formed by the treatment device12and the rigid rod50provided with the elongated hook member52is then inserted into the sheath70.

Then, the sheath70is introduced into the patient as far as the blood circulation canal in which the device12must be deployed.

The surgeon then removes the device12from the sheath70by moving the sheath70in a proximal direction, whilst keeping the treatment device12axially fixed using the rigid rod50, by means of co-operation between the support surfaces58and36. The position of the endoprosthesis in the blood vessel is therefore very precise, even if the blood circulates with a counter current in the vessel.

The elongated hook member52is then moved towards the distal end56of the rod50. Under the action of the resilience of the trellis which constitutes the endoprosthesis16, the endoprosthesis deploys from the retracted state to the expanded state thereof until the peripheral wall22of the endoprosthesis16comes into contact with the wall P of the vessel to be treated.

During this movement, the traction loop42moves closer to the proximal control opening28so that the length of the control regions40A,40B decreases and the length of the clamping regions38A,38B increases.

If the surgeon considers that the positioning of the device12is unsatisfactory, he can pull on the elongate hook member52in order to move the hook62towards the proximal end of the rod50and again bring about the contraction of the endoprosthesis16. The surgeon then replaces the endoprosthesis in a more satisfactory manner in the canal as described above.

When he considers that the position of the endoprosthesis16is satisfactory, the surgeon removes the hook62from the traction loop42and extracts the rigid rod50and the elongated hook member52from the patient.

If the endoprosthesis16subsequently has to be removed, the rigid rod50is again introduced into the blood vessel. Then, the hook62of the elongate hook member52can be engaged in the traction loop42in order to retract the endoprosthesis16as described above.

Since the traction loop42is produced using a ring of radio-opaque material, gripping of the ring using the elongated hook member52is facilitated.

In a first variant which is partially illustrated inFIG. 5, the device12comprises at least one filamentary connection20C which comprises a clamping region38C which surrounds the endoprosthesis and a control region40C whose end protrudes through the distal control opening30. This end is further provided with a loop42C which is arranged in the vicinity of the proximal end when the endoprosthesis16is in the expanded state thereof.

This device12allows the at least partial contraction of the endoprosthesis16using a rod50which is introduced via a portion of the blood vessel that is distal relative to the device12.

The treatment device110illustrated inFIGS. 6 and 7differs from the device10illustrated inFIGS. 1 to 4in that the filamentary connections20A,20B can be released.

To this end, the elongated hook member52is replaced with a retention pin112which is engaged in the rod50and in the central passage54of the post member26.

The clamping region38A,38B comprises, at one end, a loop114which is engaged round the pin112in the passage27, via a retention opening32,34.

The control region40A,40B comprises a single strand which extends longitudinally as far as the proximal end of the rigid rod50.

Initially, in order to retract the endoprosthesis16, the surgeon pulls on the proximal end of each control region40A,40B at the proximal end of the rigid rod50.

Since the clamping regions38A,38B of each connection20A,20B are retained by the loop114which is engaged on the pin112, the length of each clamping region38A,38B decreases, which brings about the contraction of the endoprosthesis16.

Then, when the device10is introduced into the vessel to be treated, each control region40A,40B is relaxed which brings about an increase in the length of the clamping region38A,38B under the action of the radial expansion of the endoprosthesis16.

When the endoprosthesis16is placed in a satisfactory manner in the vessel to be treated, the pin112is removed from the post member26, and is then extracted from the patient via the rigid rod50.

The loops114are thus released. The surgeon can then pull on the proximal end of each connection20A,20B in order to remove them from the patient.

Using the invention which has been described above, it is possible to provide a treatment device12which comprises an endoprosthesis16which can be deployed and which can be implanted in a reversible manner in a blood vessel.

The presence of a support18which is permanently fixed to the endoprosthesis and which receives at least one connection20A,20B for clamping the endoprosthesis16ensures the precise positioning of the endoprosthesis16when it is deployed, whilst simplifying the device required for the release thereof in the vessel.

Furthermore, when a connection20A,20B is permanently retained on the endoprosthesis16, it is possible to remove the endoprosthesis16from the vessel via an endoluminal route when it has to be replaced.