Improvements in or relating to ultrasonic endovascular apparatus

Abstract

An endovascular apparatus comprises an ultrasonic transducer within a housing, a passage traversing the housing, and an interface communicating with the transducer and adjoining the passage. An insert that fits into the passage has a tubular wall defining a lumen for accommodating a wire extending along the lumen. A coupling of the insert surrounds the lumen and is cooperable with the interface to engage the wire and to convey ultrasonic energy from the transducer to the wire. The apparatus is prepared for use by inserting the insert into the passage to align the coupling with the interface and then compressing the coupling to narrow the lumen into clamping engagement with the wire to energise the wire via the interface and the coupling. By maintaining a seal that isolates the wire in the lumen, the insert is removable after use to allow re-use of the housing, the transducer and the interface.

Description

[0001] Improvements in or relating to ultrasonic endovascular apparatus

[0002] This invention relates to devices that employ ultrasonically-actuated endovascular elements, such as wires, serving as waveguides to cross through obstructions in blood vessels. Such devices can also be used to characterise such obstructions and more generally to determine the condition of blood vessels. Examples of such devices and clinical uses are disclosed in our PCT applications published as WO 2020 / 094747, WO 2021 / 224357, WO 2021 / 089847, WO 2021 / 089859, WO 2022 / 129623 and WO 2023 / 111361.

[0003] The system exemplified in our abovementioned PCT applications comprises an ultrasonic system controller and an actuator. The actuator contains an ultrasonic transducer and a coupling, such as a collet, that is arranged to couple to, and to manage ultrasonic activation of, an active wire. The coupling can be clamped to the wire at any chosen location along the length of the wire to convey ultrasonic energy from the transducer into the wire.

[0004] Thus, the wire extends through the actuator along a lumen or passage that extends along a length of the actuator and sections of the wire protrude distally and proximally from the actuator. The energy imparted to the wire may be applied differentially in the distal and proximal sections of the wire. For example, it may be desirable selectively to damp vibration of the proximal section of the wire.

[0005] For efficient use of resources, it is desirable to be able to re-use at least some components of the actuator, including its housing, the transducer and related structures such as an acoustic horn. However, the wire that extends, in use, into a patient’s vasculature also extends into the long, narrow lumen of the actuator where the wire is coupled to the transducer. This makes it challenging to clean and sterilise the actuator internally and so militates against re-use of its components.

[0006] An aim of the invention is to simplify cleaning and sterilisation and / or to maintain reusable components of the actuator in a sterile field, while still facilitating clamping, release, repositioning and selective damping of the wire.

[0007] Against this background, the invention resides in an endovascular apparatus that comprises: a source of ultrasonic energy disposed within a housing; a passage extending through the housing; an interface in communication with the source and adjoining the passage; and a tubular insert configured to fit into the passage and having a tubular wall defining a lumen, at least as long as the passage, for accommodating an elongate endovascular element that can extend along the lumen. The insert further comprises a coupling that surrounds the lumen and that is cooperable with the interface to engage the endovascular element and to convey ultrasonic energy from the source to the endovascular element, when the endovascular element is in the lumen.

[0008] The interface may be configured to compress the coupling radially inwardly to narrow the lumen into clamping engagement with an endovascular element in the lumen. A collet can serve either as the coupling or as the interface. In the latter case, the coupling may be configured to impart lateral flexibility locally in the tubular wall of the insert. For example, the coupling may comprise a longitudinal series of rings embedded in an elastic matrix.

[0009] Where a collet is employed, a head of the collet can protrude from the distal opening when the insert is fitted into the passage. The head of the collet may be shaped to facilitate applying torque to the collet. A cap may be engaged or engageable with the head of the collet and may be configured to apply torque to the head.

[0010] A proximal end portion of the insert can protrude from the proximal opening when the insert is fitted into the passage, and may protrude through an aperture in a sterile cover or drape that extends around and proximally beyond the housing.

[0011] The insert may comprise an isolator section that is configured to attenuate transmission of ultrasonic oscillation proximally and / or distally along the insert from the coupling. The isolator section can comprise at least one opening penetrating the tubular wall of the insert, which opening may, for example, extend helically around and along the isolator section. A flexible sheath on the isolator section can seal across the opening.

[0012] The insert may comprise a damping section that is configured to impart lateral flexibility locally in the tubular wall of the insert. For example, the damping section may comprise at least one opening that penetrates the tubular wall of the insert, such as one or more longitudinally-extending slots. Again, a flexible sheath can seal across the or each opening. As another option, the isolator section and / or the damping section can comprise a longitudinal series of rings that are embedded in an elastic matrix.

[0013] The actuator can include a damping mechanism with which the damping section aligns when the insert is fitted into the passage. The damping mechanism can be configured to compress the insert radially inwardly to narrow the lumen into damping engagement with an endovascular element, when such an element is in the lumen.

[0014] Correspondingly, the inventive concept embraces a tubular insert for an endovascular apparatus, the insert comprising: a tubular wall defining a lumen for accommodating an elongate endovascular element that can extend along the lumen in use; and a coupling that surrounds the lumen and is configured to be compressible radially inwardly to narrow the lumen into clamping engagement with the endovascular element in the lumen.

[0015] The coupling may be a collet, in which case the collet may comprise a head that is configured for application of torque to the collet. The insert may be provided with a cap that is engaged or engageable with the head and that is configured to apply torque to the head.

[0016] The coupling may be configured to impart lateral flexibility locally in the tubular wall of the insert, for example by comprising a longitudinal series of rings that are embedded in an elastic matrix.

[0017] The insert may further comprise an isolator section that is configured to attenuate transmission of ultrasonic oscillation along the insert from the coupling and / or a damping section that is configured to impart lateral flexibility locally in the tubular wall of the insert. The coupling may also serve as the isolator section.

[0018] The inventive concept also embraces a corresponding method of preparing an endovascular apparatus for use. The method comprises: inserting a tubular insert into a passage that extends through a housing of the apparatus, the insert being at least as long as the passage; aligning a coupling of the insert with an interface adjoining the passage, the interface being in communication with a source of ultrasonic energy disposed within the housing; and by interaction between the interface and the coupling, compressing the coupling radially inwardly to narrow a lumen of the insert into clamping engagement with an endovascular element disposed in the lumen to convey ultrasonic energy from the source to the endovascular element via the interface and the coupling.

[0019] Torque may be applied to the coupling or to the interface to clamp the insert to the endovascular element, for example by applying torque to a head of the coupling or of the interface that protrudes from the housing.

[0020] The method of the invention can maintain a seal that isolates the lumen of the insert and the endovascular element from the housing, the source and the interface. Thus, after use, the insert can be removed from the passage and the housing, the source and the interface can be re-used.

[0021] In summary, the invention provides a sterile disposable ultrasonic coupling insert for an actuator that isolates the actuator from direct contact with contaminating fluids, such as a patient’s blood, to allow the actuator to be cleaned and re-used in another procedure to be performed on another patient. More specifically, a differential activation retention tube can separate an active wire from wearing portions of the actuator, such as a collet head of a distal coupling mechanism and a proximal damping mechanism used for differential damping, to enable potential reuse of the transducer and other actuator components.

[0022] The insert mediates transmission of ultrasonic energy from the actuator into an active wire via a collet. Once appropriate torque has been applied to the collet through a locking cap mechanism, the coupling exerts clamping force required to couple the wire mechanically to an ultrasonic transducer of the actuator. This provides a means of conveying ultrasonic vibration from the transducer into the wire and a means of firmly gripping and holding the wire to allow its manipulation during use of the ultrasonic device.

[0023] The insert provides a mechanism to achieve longer operational life from the actuator, extending its scope of operation by enabling multiple use. Optionally, the insert also provides for differential damping of the wire.

[0024] In summary, an endovascular apparatus of the invention comprises an ultrasonic transducer within a housing, a passage traversing the housing, and an interface communicating with the transducer and adjoining the passage. A collet can serve as the interface or as the coupling. An insert that fits into the passage has a tubular wall defining a lumen to accommodate a wire that extends along the lumen. A coupling of the insert surrounds the lumen and is cooperable with the interface to engage the wire and to convey ultrasonic energy from the transducer to the wire.

[0025] The apparatus can be prepared for use by inserting the insert into the passage to align the coupling with the interface and then the coupling is compressed by interaction with the interface to narrow the lumen into clamping engagement with the wire. In use, the wire can then be energised via the interface and the coupling. By maintaining a seal that isolates the wire in the lumen, the insert is removable after use to allow re-use of the housing, the transducer and the interface.

[0026] In order that the invention can be more readily understood, reference will now be made, by way of example, to the accompanying drawings in which:

[0027] Figure 1 is a perspective view of a first embodiment of an ultrasonic coupling insert of the invention;

[0028] Figure 2 is a side view in longitudinal section of the insert of Figure 1 inserted into an actuator of the invention;

[0029] Figures 3a, 3b and 3c are schematic side views showing how the insert can respond to longitudinal oscillations imparted by the actuator;

[0030] Figure 4 is an enlarged detail side view of a proximal damping mechanism of the actuator of Figure 2;

[0031] Figure 5a is a perspective view of the insert of Figure 1 being inserted into the actuator of Figure 2;

[0032] Figure 5b corresponds to Figure 5a but shows the insert of Figure 1 fully inserted into the actuator of Figure 2, and with an active wire extending through the insert and the actuator;

[0033] Figure 6 is perspective view of a second embodiment of an ultrasonic coupling insert of the invention;

[0034] Figure 7 is an enlarged perspective view corresponding to Detail VII in Figure 6; Figure 8 is a side view in longitudinal section of the insert of Figure 6 inserted into an actuator of the invention;

[0035] Figure 9 is an enlarged detail side view of a collet interface between the insert of Figure 6 and the actuator of Figure 8; and

[0036] Figure 10 is an enlarged detail side view of a variant of the actuator of Figure 8.

[0037] Referring firstly to Figure 1 , a disposable insert 10 of the invention comprises an elongate and substantially straight tubular body 12. The body 1 may, for example, be machined of a metal such as stainless steel, nitinol or cobalt-chromium alloy, whose mechanical properties allow high-fidelity transmission of oscillation at ultrasonic frequencies.

[0038] In proximal succession, the insert 10 comprises a coupling exemplified here by an integral collet 14, an isolator section 16 on a proximal side of the collet 14 and a damping section 18 near a proximal end of the insert 10. The isolator section 16 and the damping section 18 are optional but preferred features of the insert 10.

[0039] In this example, the collet 14 is joined to the body 12 at a distal end of the insert 10.

[0040] The collet 14 comprises clamping jaws 20 that are angularly spaced around a lumen of the insert 10 centred on a central longitudinal axis 22. The jaws 20 are separated by radial slots 24 that lie in convergent planes containing the central longitudinal axis 22.

[0041] A head 26 of the collet 14 is configured to be engaged by a complementary female formation of a cap, to be described below, to impart torque that can turn the collet 14 about the central longitudinal axis 22. In this example, the head 26 has a hexagonal configuration although other polygonal, splined or keyed configurations are also possible.

[0042] The jaws 20 taper proximally from the head 26 through a frusto-conical intermediate section 28 of the collet 14 down to a male-threaded proximal section 30 of the collet 14. The jaws 20 are cantilevered distally from the proximal section 30. The proximal taper of the intermediate section 28 defines a proximally- and outwardly-facing wedge surface that tapers proximally toward the central longitudinal axis 22. Referring now also to Figure 2, an actuator 32 comprises a housing 34 that contains a transducer 36 in series with an acoustic horn 38 extending distally from the transducer 36. The transducer 36 and the acoustic horn 38 are both annular, encircling a passage 40 that extends along a full length of the housing 34 and terminates in distal and proximal openings.

[0043] The passage 40 of the actuator 32 receives the insert 10 telescopically as a close sliding fit, with a proximal end of the insert 10 being inserted initially into a distal end of the passage 40. Insertion of the insert 10 continues proximally until the male-threaded proximal section 30 of the collet 14 engages a complementary female-threaded socket 42 in a distal end of the acoustic horn 38. The socket 42 serves as an interface for conveying ultrasonic energy from the transducer 36 to the collet 14.

[0044] Turning the collet 14 by applying torque to the head 26 advances the proximal section 30 of the collet 14 proximally along the thread of the socket 42 until the frusto-conical intermediate section 28 of the collet 14 bears against a complementary distally-flared wedge surface of the socket 42, which serves as the distal opening of the passage 40. Continued proximal movement of the collet 14 drives wedging interaction between the mutually-opposed wedge surfaces of the intermediate section 28 and the socket 42. This causes the jaws 20 of the collet 14 to clamp inwardly around an active wire 44, shown here protruding from the insert 10 and extending along the central longitudinal axis 22. Clamping the wire 44 in this way couples the transducer 36 to the wire 44 via the acoustic horn 38 and the collet 14.

[0045] It will be noted from Figure 2 that the insert 10 extends along the entire length of the passage 40 in the actuator 32, with the head 26 of the collet 14 protruding from a distal end of the housing 34 and a proximal end portion of the insert 10 protruding from an aperture in the proximal end of the housing 34, serving as the proximal opening of the passage 40. In use, the insert 10 and the actuator 32 can be assembled in a sterile field such that the insert 10, extending through the full length of the actuator 32, maintains a sterile path about the active wire 32 bounded by a continuous sterile barrier between the active wire 44 and the actuator 32.

[0046] Returning to Figure 1 , and referring now also to Figures 3a to 3c, the purpose of the isolator section 16 is to isolate the portion of the insert 10 proximal to the isolator section 16 from longitudinal oscillations that are transmitted from the transducer 36 into and through the collet 14 to the active wire 44 in use. For this purpose, the isolator section 16 is longitudinally flexible, relative to the remainder of the tubular body 12, to be capable of extending and contracting longitudinally in response to longitudinal motion of the collet 14 as shown in Figures 3a to 3c. Thus, in this example, a helical slit 46 penetrating the tubular wall of body 12 extends along and around the isolator section 16. One or more vibration-isolating slits in the tubular wall of the isolator section 16 could instead extend axially, circumferentially or diagonally.

[0047] To maintain a hermetic seal between the exterior of the insert 10 exposed to the actuator 32 and the interior of the insert 10 exposed to the active wire 44, the isolator section 16 is wrapped or sleeved with a tubular barrier sheath 48 that covers the slit 46. Preferably, as shown here, the sheath 48 is of a thin, flexible and elastic polymer that lengthens and shortens with corresponding longitudinal extension and contraction of the isolator section 16. The sheath 48 may be fixed to the body 12 of the insert 10 with adhesive, heat shrunk to the body 12 or otherwise mechanically fixed to the body 12 to separate the sterile lumen of the insert 10 from the non-sterile assembly of the actuator 32.

[0048] Returning to Figures 1 and 2, and referring now also to Figure 4, the purpose of the damping section 18 is to impart lateral flexibility in the tubular wall of the body 12. This allows a damping mechanism 50 of the actuator 32 to bear radially inwardly against the body 12, applying lateral compressive force to deflect the wall of the body 12 against the active wire 44. Resulting contact between the wall of the body 12 and the active wire 44 damps activation of the proximal section of the active wire 44.

[0049] Figures 1 , 2 and 4 exemplify the damping section 18 as being at least one longitudinally-extending compression slot 52 that penetrates the tubular wall of the insert 10. The compression slot 52 may have varying geometry or dimensions to ensure uniform deformation of the slot and therefore even distribution of the clamping force applied to the wire 44.

[0050] In the example shown in Figures 2 and 4, the damping mechanism 50 comprises a button 54 that protrudes from the housing 34 of the actuator 32 and acts on a longitudinally-extending press member 56. Pushing the button 54 presses the press member 56 radially inwardly against the insert 10 in alignment with the damping section 18 along the length of the compression slot 52. Again, to maintain a seal between the exterior of the insert 10 exposed to the actuator 32 and the interior of the insert 10 exposed to the active wire 44, the damping section 18 is wrapped or sleeved with a tubular barrier sheath 58 that covers the compression slot 52. The sheath 58 is of a thin, flexible and elastic polymer that contracts resiliently with corresponding deflection of the underlying tubular wall of the insert 10. The sheath 58 may be fixed with adhesive, heat shrunk to the insert 10 or otherwise mechanically fixed to the insert 10.

[0051] Turning now to Figures 5a and 5b, these drawings show the actuator 32 and a power lead 60 extending proximally from the actuator 32 to an external power source such as an ultrasonic system controller. The actuator 32 and the power lead 60 are both sheathed by a flexible tubular sterile cover 62 that is sealed at a distal end to a distal end of the actuator 32 and is draped proximally over the actuator 32 and along the power lead 60. The actuator 32 and the power lead 60 are thereby maintained within a sterile field inside the cover 62.

[0052] Figure 5a shows the insert 10 as part of a cartridge 64 that further comprises a cap 66 at a distal end of the insert 10. The head 26 of the collet 14 is engaged within the cap 66 in male-female relation is and surrounded by a proximally-facing skirt 68 of the cap 66. With a user holding the cap 66 by the skirt 68, the cartridge 64 is pushed proximally onto the distal end of the actuator 32, thereby pushing the insert 10 into and along the passage 40 of the actuator 32.

[0053] With continued proximal movement of the cartridge 64, the skirt 68 of the cap 66 telescopically receives and surrounds a tubular distal nose 70 formed in the housing 34 of the actuator 32. When the threads of the proximal section 30 of the collet 14 and the socket 42 of the acoustic horn 38 engage, the cap 66 is turned to apply clamping torque to the collet 14 via the head 26 after an active wire 44 has been inserted into and through the insert 10 as shown in Figure 5b. The interface between the cap 66 and the head 26 of the collet 14 could be arranged to ensure that a predetermined torque value is applied to the collet 14, for example by the cap 66 slipping or ratcheting relative to the head 26 when the predetermined torque value has been reached.

[0054] Figure 5b shows a proximal end portion of the insert 10 protruding from a proximal end of the housing 34, together with a proximal section of the active wire 44. In this example, the proximal end portion of the insert 10 and the proximal section of the active wire 44 protrude through an aperture 72 provided in the sterile cover 62, also visible in Figure 5a. The aperture 72 may, for example, be surrounded by a grommet that seals around the proximal end portion of the insert 10. It could instead be possible simply to push the proximal end portion of the insert 10 through the cover 62 to form the aperture 72.

[0055] The insert 10, or a cartridge 64 including the insert 10 and a cap 66, can be provided as part of a procedure kit that can be packed in a pouch or other sterile packaging. The components of the kit are then removed from their packaging for use in a sterile use environment. The cap 66 can remain attached to and be disposed with the insert 10 after use or can be separated from the insert 10 for reuse after sterilisation. Upon removal of the insert 10, the non-sterile actuator 32 can easily be wiped clean and placed within a fresh sterile cover 62, allowing reuse of the actuator 32 in a sterile field.

[0056] Figures 6 to 10 show a second embodiment of the invention. Like numerals are used for like features.

[0057] In Figure 6, a disposable insert 10 of the invention again comprises an elongate tubular body 12, such as a hypo tube, that may similarly be machined of a suitable metal. In this case, the insert 10 comprises a coupling section 74 near a distal end of the insert 10 and a damping section 18 near a proximal end of the insert 10. Also, the body 12 may have a flared distal end to ease insertion of an active wire 44.

[0058] The coupling section 74 and the damping section 18 could be formed integrally with the metal of the body 12 but in this example are interposed between sections of the body 12 in longitudinal series. As best appreciated in the enlarged detail view of Figure 7, a ring or flange 76 of slightly greater diameter than the body 12 extends circumferentially around the body 12 on a part of the body 12 that is distal to the coupling section 74.

[0059] The flange 76 serves as a location ring and may be moulded or machined into the body 12 or attached to the body 12.

[0060] Like the damping section 18, the coupling section 74 imparts lateral flexibility in the tubular wall of the insert 10. This allows local application of lateral compressive force to deflect the wall of the insert 10 inwardly into contact with the active wire 44. In the coupling section 74, contact between the wall of the insert 10 and the active wire 44 clamps the active wire 44 to convey ultrasonic energy generated by the transducer 36. Thus, in this embodiment, clamping force is exerted on the active wire 44 via the flexible wall of the insert 10. In this embodiment, a collet 14 distinct from the insert 10 acts on the coupling section 74 to apply the lateral compressive force that effects clamping onto the active wire 44. Consequently, the insert 10 is inserted into and through the collet 14 on assembly with the actuator 32 and the collet 14 can remain attached to the actuator 32 before and after the insert 10 is assembled with the actuator 32. Also, the collet 14 remains isolated from the lumen of the insert 10, enabling the collet 14 to be another reusable part of the actuator 32.

[0061] Referring now also to Figure 8, the passage 40 of the actuator 32 receives the insert 10 telescopically as a close sliding fit, with a proximal end of the insert 10 being inserted initially into a distal end of the passage 40 through the collet 14. Insertion of the insert 10 continues proximally until the flange 76 encircling the body 12 engages a complementary groove 78 within the collet 14 as a snap fit, as shown in Figure 9. The coupling section 74 of the insert 10 is thereby aligned longitudinally with and within the collet 14.

[0062] The insert 10 can be inserted into the passage 40 through a cap 66 that is engaged with a head 26 of the collet 14. Turning the cap 66 around the insert 10 turns the collet 14 by applying torque to the head 26. This rotation advances the collet 14 proximally along the thread of a socket 42 in the distal end of an acoustic horn 38 to bear against a complementary wedge surface 80 of the socket 42, as also shown in Figure 9.

[0063] Continued proximal movement of the collet 14 drives wedging interaction between the collet 14 and the socket 42 that causes the collet 14 to clamp inwardly around the coupling section 74 of the insert 10. The coupling section 74, in turn, clamps inwardly onto the wire 44 to couple ultrasonic energy from the transducer 36 into the wire 44.

[0064] In addition to clamping the wire 44 in consequence of the clamping action of the collet 14, the coupling section 74 performs the function of the isolator section 16 of the first embodiment. This is to isolate the portion of the insert 10 proximal to the coupling section 74 from longitudinal oscillations that are transmitted from the transducer 36 into and through the collet 14 to the active wire 44 in use. For this purpose, the coupling section 16 is longitudinally flexible, relative to the remainder of the tubular body 12, to be capable of extending and contracting longitudinally in response to longitudinal motion of the collet 14. In this embodiment, the coupling section 74 is similarly capable of isolating the portion of the insert 10 distal to the coupling section 74 from longitudinal oscillations driven by the transducer 36. This facilitates use of a distal section of the insert 10 protruding distally from the actuator 32, for example to protect a corresponding distal section of the wire 44 and to bridge between the actuator 32 and a luer connector that, in use, leads the wire into a patient’s vasculature.

[0065] As best appreciated in Figures 7 and 9, the coupling section 74 comprises a longitudinal series of parallel rings 82, each ring 82 lying in a respective plane orthogonal to the central longitudinal axis 22 of the insert 10. The rings 82 have cut-outs 84 that facilitate lateral compression of the rings 78 under clamping force applied by the collet 14. The rings 82 are decoupled from each other and held in a tubular alignment by being embedded in a tubular body or matrix 86 of a thermally stable elastic or viscoelastic polymer that may, for example, be filled by carbon fibre filaments or PTFE. Other flexible transmission structures such as interdigitating cylinders are possible.

[0066] In the example shown in Figure 6, the damping section 18 of the insert 10 comprises a similar series of rings 82 embedded in a tubular body or matrix 86 of an elastomeric polymer. Other damping configurations such as the compression slots of the first embodiment could be used instead in the damping section 18. The actuator 32 shown in Figure 8 has a damping mechanism 50 like that of the first embodiment acting on the damping section 18. Other damping mechanisms are possible.

[0067] Finally, Figure 10 shows the option of a snap-fit arrangement for retaining the cap 66 on the tubular distal nose 70 of the actuator 32. In this example, a shoulder 88 on the nose 70 cooperates with a resilient snap-hook formation on the skirt 68 of the cap 66. This prevents accidental removal of the cap 66 from the actuator 32 but allows the cap 66 to be removed from the actuator 32 with a deliberate pulling action.

[0068] Many other variations are possible within the inventive concept. For example, the insert could be sheathed along its length with a single sheath that extends between, and covers any openings in, both the isolator section and the damping section. The damping mechanism could act on the wire through a window in an insert, for example via a flexible or elastomeric membrane that maintains a seal between the wire and the interior of the actuator. Conversely, the isolator section and / or the damping section could perform their functions without requiring openings penetrating the tubular wall of the insert and therefore without requiring a sheath, membrane or matrix to cover any such openings. In this respect, the wall of the insert could be thinned by grooves or shaped by formations of curved section, such as corrugations, that extend longitudinally, circumferentially or helically to increase local flexibility in the wall.

Claims

Claims1. An endovascular apparatus comprising: a source of ultrasonic energy disposed within a housing; a passage extending through the housing between distal and proximal openings; an interface in communication with the source and adjoining the passage; and a tubular insert configured to fit into the passage and having a tubular wall defining a lumen, at least as long as the passage, for accommodating an elongate endovascular element extending along the lumen; wherein the insert further comprises a coupling that surrounds the lumen and is cooperable with the interface to engage an endovascular element and to convey ultrasonic energy from the source to an endovascular element, when an endovascular element is in the lumen.

2. The apparatus of Claim 1 , wherein the interface is configured to compress the coupling radially inwardly to narrow the lumen into clamping engagement with an endovascular element, when an endovascular element is in the lumen.

3. The apparatus of any preceding claim, wherein the coupling is a collet.

4. The apparatus of Claims 1 or Claim 2, wherein the interface is a collet.

5. The apparatus of Claim 4, wherein the coupling is configured to impart lateral flexibility locally in the tubular wall of the insert.

6. The apparatus of Claim 5, wherein the coupling comprises a longitudinal series of rings embedded in an elastic matrix.

7. The apparatus of any of Claims 3 to 6, wherein a head of the collet protrudes from the distal opening when the insert is fitted into the passage.

8. The apparatus of Claim 7, wherein the head of the collet is shaped for applying torque to the collet.

9. The apparatus of Claim 8, further comprising a cap engaged or engageable with the head of the collet and configured to apply torque to the head.

10. The apparatus of any preceding claim, wherein a proximal end portion of the insert protrudes from the proximal opening when the insert is fitted into the passage.

11. The apparatus of any preceding claim, wherein the insert comprises an isolator section configured to attenuate transmission of ultrasonic oscillation along the insert from the coupling.

12. The apparatus of Claim 11 , wherein the isolator section comprises at least one opening penetrating the tubular wall of the insert.

13. The apparatus of Claim 12, wherein the at least one opening extends helically around and along the isolator section.

14. The apparatus of Claim 12 or Claim 13, further comprising a flexible sheath on the isolator section, sealing across the at least one opening.

15. The apparatus of Claim 11, wherein the isolator section comprises a longitudinal series of rings embedded in an elastic matrix.

16. The apparatus of any preceding claim, wherein the insert comprises a damping section configured to impart lateral flexibility locally in the tubular wall of the insert.

17. The apparatus of Claim 16, wherein the damping section comprises at least one opening penetrating the tubular wall of the insert.

18. The apparatus of Claim 17, wherein the at least one opening is a longitudinally- extending slot.

19. The apparatus of Claim 17 or Claim 18, further comprising a flexible sheath on the damping section, sealing across the at least one opening.

20. The apparatus of Claim 16, wherein the damping section comprises a longitudinal series of rings embedded in an elastic matrix.

21. The apparatus of any of Claims 16 to 20, wherein the actuator includes a damping mechanism that is aligned with the damping section when the insert is fitted into the passage and is configured to compress the insert radially inwardly to narrow the lumen into damping engagement with an endovascular element, when an endovascular element is in the lumen.

22. A tubular insert for an endovascular apparatus, the insert comprising: a tubular wall defining a lumen for accommodating an elongate endovascular element extending along the lumen; and a coupling that surrounds the lumen and is configured to be compressible radially inwardly to narrow the lumen into clamping engagement with an endovascular element, when an endovascular element is in the lumen.

23. The insert of Claim 22, wherein the coupling is a collet.

24. The insert of Claim 23, comprising a head that is configured to apply torque to the collet.

25. The insert of Claim 24, further comprising a cap that is engaged or engageable with the head and is configured to apply torque to the head.

26. The insert of Claim 22, wherein the coupling is configured to impart lateral flexibility locally in the tubular wall of the insert.

27. The apparatus of Claim 26, wherein the coupling comprises a longitudinal series of rings embedded in an elastic matrix.

28. The insert of any of Claims 22 to 27, further comprising an isolator section that is configured to attenuate transmission of ultrasonic oscillation along the insert from the coupling.

29. The insert of any of Claims 22 to 28, further comprising a damping section configured to impart lateral flexibility locally in the tubular wall of the insert.

30. A method of preparing an endovascular apparatus for use, the method comprising: inserting a tubular insert into a passage that extends through a housing of the apparatus, the insert being at least as long as the passage; aligning a coupling of the insert with an interface adjoining the passage, the interface being in communication with a source of ultrasonic energy disposed within the housing; and by interaction between the interface and the coupling, compressing the coupling radially inwardly to narrow a lumen of the insert into clamping engagement with an endovascular element disposed in the lumen to convey ultrasonic energy from the source to the endovascular element via the interface and the coupling.

31. The method of Claim 30, comprising applying torque to the coupling to clamp the insert to the endovascular element.

32. The method of Claim 30, comprising applying torque to the interface to clamp the insert to the endovascular element.

33. The method of Claim 31 or Claim 32, comprising applying torque to a head of the coupling or the interface that protrudes from the housing.

34. The method of any of Claims 30 to 33, comprising maintaining a seal that isolates the lumen of the insert and the endovascular element from the housing, the source and the interface.

35. The method of any of Claims 30 to 34 and further comprising, after use, removing the insert from the passage and re-using the housing, the source and the interface.

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