Pivot operated vascular intervention device delivery system

A vascular intervention device delivery system, such as for implanting a self expanding stent, includes a thumbwheel rotatably mounted in a handle. The thumbwheel includes a radially outward thumb surface and a radially outward toothed surface that may be moved into and out of contact with a catch by mounting the thumbwheel on a pivot plate within the handle. The pivot plate may be pivoted with respect to the handle between a locked position to prevent rotation of the thumbwheel, and an unlocked position that permits rotation of the thumbwheel. A catheter has a proximal end attached to the handle, and a distal carrier segment for mounting a vascular intervention device thereon. A retractable sheath is movable from a first position covering the distal carrier segment to a second position retracted proximally uncovering the distal carrier segment. A pull extends between the thumbwheel and the retractable sheath.

TECHNICAL FIELD

The present disclosure relates generally to vascular intervention device delivery systems, and more particularly to a feature that holds the thumbwheel against rotation in one direction, but permits rotation in an opposite direction for deployment of a vascular intervention device.

BACKGROUND

Self expanding stents and similar vascular intervention devices are often delivered and deployed using so called pin and pull systems. Typically, the stent is compressed between a retractable outer sheath and an inner catheter. To deploy the stent, the user has to pull the outer sheath to uncover the stent using one hand while resisting the force with the other hand on the inner catheter to maintain the position of the stent during deployment. In pin and pull systems, the user can have difficultly maintaining the inner catheter at a fixed position while simultaneously moving the outer sheath. In very difficult stent deployments, which require a large amount of force by the user, this simultaneous push and pull may lead to inaccurate stent positioning, shortening or lengthening of the stent, or possibly even damage to the stent or target vessel. Another disadvantage of pin and pull systems is that there can be a lack of control on the deployment because the force to deploy the stent decreases as more of the stent is deployed. If the user maintains the same high force during deployment, the stent may be deployed too fast for the user to control. Another potential problem relates to building up tension in the outer sheath prior to movements thereof during the deployment process. If the user pauses during the deployment and releases this built up tension, deployment errors can occur when the user resumes tension to again move the outer sheath to the deployment position fully uncovering the self explaining stent.

The present disclosure is directed toward one or more of the problems set forth above.

SUMMARY OF THE DISCLOSURE

In one aspect, a vascular intervention device delivery system includes a handle with a catch positioned therein. A pivot plate is mounted in the handle, and is pivotable about a first axis with respect to the handle between a locked position and an unlocked position. The pivot plate supports an axle that defines a second axis. A thumbwheel is rotatably mounted on the axle and has a radially outward thumb surface and a radially outward toothed surface. The radially outward toothed surface is in contact with the catch when the pivot plate is at the locked position to prevent rotation of the thumbwheel in a forward direction, and the radially outward toothed surface is out of contact with the catch when the pivot plate is at the unlocked position to permit rotation of the thumbwheel in a reverse direction. A catheter has a proximal end attached to the handle, and has a distal carrier segment for mounting a vascular intervention device thereon. A retractable sheath is movable from a first position covering the distal carrier segment to a second position retracted proximally uncovering the distal carrier segment. A pull extends between the thumbwheel and the retractable sheath. The retractable sheath moves responsive to rotation of the thumbwheel in the reverse direction.

In another aspect, a method of operating the vascular intervention device delivery system includes pivoting the pivot plate from the locked position to the unlocked position. The thumbwheel is rotated in the reverse direction to build up tension in the retractable sheath and pull without moving the retractable sheath relative to the distal carrier segment of the catheter. A portion, which is less than all, of the distal carrier segment is uncovered by continuing to rotate the thumbwheel in the reverse direction. Rotation of the thumbwheel in the reverse direction is paused. The pivot plate is pivoted from the unlocked position to the locked position. Tension in the pull and the retractable sheath is maintained by preventing rotation of the thumbwheel in the forward direction. The pivot plate is again pivoted form the locked position to the unlocked position. A remaining portion of the distal carrier segment is uncovered by resuming rotation of the thumbwheel in the reverse direction.

DETAILED DESCRIPTION

Referring toFIGS. 1-3, a vascular intervention device delivery system10is shown before and during delivery of a self expanding stent45into the vessel50of a patient. Delivery system10includes a handle11that may be gripped in one hand by a user during a delivery procedure. Handle11may, for instance, be manufactured from a suitable molded plastic, such as in two longitudinal halves that are joined in any suitable manner to form the complete handle11. A thumbwheel15is rotatably mounted in the handle11and has a radially outward thumb surface16and a spool17. A catheter30has a proximal end31attached to handle11, and a distal carrier segment32for mounting a vascular intervention device, such as a self expanding stent45, thereon. Proximal end31may take the form a Luer lock fitting so that treatment fluids or the like may be injected through catheter30in a manner well known in the art. A retractable sheath37is movable with respect to catheter30from a first position covering the distal carrier segment32to a second position indicated by the dashed line inFIG. 3at which the retractable sheath37has been retracted proximally to uncover the distal carrier segment32.FIG. 3shows the retractable sheath37about half way between the first position and the second position.

A pull38extends between the spool17of thumbwheel15and the retractable sheath37. Pull38, which preferably is less elastic than the retractable sheath37, may be attached to retractable sheath37at an attachment39in any manner known in the art. In most versions of the vascular intervention device delivery system10of the present disclosure, pull38will be longer than retractable sheath37. Nevertheless, retractable sheath37could be longer than pull38without departing from the present disclosure. Pull38may comprise a metallic wire or thin band of metal.

A wire retention/stability sheath42surrounds a majority of the length of pull38, and serves to keep pull38in close proximity to the outer surface of catheter30over much of the length of delivery system10. Wire retention/stability sheath42may be unattached to catheter30, pull38or retractable sheath37, but may be attached to move with pull38and/or retractable sheath37. On the other hand, wire retention/stability sheath42may be attached to catheter30at one or more locations so that pull38and retractable sheath37also move with respect to wire retention/stability sheath42during the delivery process. Wire retention/stability sheath42may terminate at its proximal end at a fixation point within handle11.

When in its pre-deployment configuration, as shown inFIGS. 1 and 2, a vascular intervention device, such as a self expanding stent45, is disposed between an outer surface of the distal carrier segment32of catheter30, and an inner surface of the retractable sheath37. During a typical procedure, the distal carrier segment32is positioned at a treatment location within a vessel50of a patient. After achieving proper positioning, the user then grips handle11and begins to rotate thumbwheel15so that pull38is wound onto spool17. As this occurs, pull38and retractable sheath37move proximally with respect to catheter30to allow the self expanding stent45to expand away from carrier segment32and into contact with the inner wall of vessel50in a manner well known in the art. During this process, catheter30is placed in compression while both pull38and retractable sheath37are in tension. According to the present disclosure, handle11and thumbwheel15include a structure that allows thumbwheel16to rotate to wind pull38onto spool17, but prevent rotation in an opposite direction. This aspect of the disclosure allows the user to stop the deployment procedure while retaining the stored elastic energy in pull38and retractable sheath37.

Referring now in addition toFIGS. 4-6, the interaction between a catch20and a radially outward toothed surface19of thumbwheel15provides the structure by which the thumbwheel15can be prevented from rotating after tension has been built up in the pull38and retractable sheath37. In particular, handle11may be formed to include, or have attached to an inner surface, an assembly plate12. Assembly plate12may include mounting bores23for attachment to an inner surface of handle11in a conventional manner, such as by use of fasteners. Catch20may be a portion of a catch plate27that is mounted to assembly plate12, such as by the use of two fasteners in a slotted connection. A pivot plate18is mounted to assembly plate in handle11at an axis25. Pivot plate18, is pivotable about axis25with respect to handle11between a locked position (as shown) and an unlocked position. The pivot plate18supports an axle13that defines an axis of rotation14for thumbwheel15. Thumbwheel15is rotatably mounted on axle13and includes both the radially outward thumb surface16and a radially outward toothed surface19. The radially outward toothed surface19is in contact with the catch20when the pivot plate18is at the locked position (as shown) to prevent rotation of the thumbwheel in a forward direction, and the radially outward toothed surface19is out of contact with the catch20when the pivot plate18is at the unlocked position to permit rotation of the thumbwheel in a reverse direction to deploy the self-expanding stent45. A spring21may be operably positioned to bias the pivot plate18toward the locked position. Although not necessary, the radially outward toothed surface19may include a plurality of teeth24in each of four 90° rotation angles. In the embodiment shown, the radially outward toothed surface19includes at least thirty teeth24around its circumference.

In the illustrated embodiment, pull38may comprise a metallic band that is oriented perpendicular to both the thumbwheel axis14and the pivot plate axis25, which are oriented parallel to each other. The pivot axis25may be separated from the thumbwheel axis14by a distance28that is greater than a diameter of thumbwheel15.

Referring now toFIG. 7-9, a vascular intervention device delivery system60according to another aspect is very similar to the earlier embodiment except thumbwheel65includes a differently shaped radially outward thumb surface66that is more easily engageable by a lock80. In most respects, vascular intervention device delivery system60is similar to the earlier embodiment except turned upside down, and identical numbers are used to identify similar features in both embodiments.

Vascular intervention device delivery system60includes a handle61within which assembly plate12as described earlier is mounted. Assembly plate12includes a pivot plate18that supports an axle63that defines a thumbwheel axis of rotation64. Like the earlier embodiment, thumbwheel65includes both a radially outward thumb surface66, a spool67and a radially outward toothed surface69. Like the earlier embodiment, thumbwheel65may include a spool67upon which pull38is wound when the device delivery system60is operated. In this version, the wire retention/stability sheath42terminates at a junction box43(not shown inFIG. 7for sake of clarity) positioned within handle61. As in the previous version, the pull38is positioned within the wire retention/stability sheath42, and emerges from the junction box43to wrap around an idler wheel44and return in a reverse direction for being wound onto spool67as best shown inFIGS. 7 and 8.

In addition to catch20and pivot plate18, vascular intervention device delivery system60includes a lock80that allows thumbwheel65to be disabled during shipment and during positioning of the distal carrier segment32(FIGS. 1-3) at a treatment location within a patient. The lock80is moveable between a locked position, as shown, and an unlocked position shown by dashed lines. The lock80includes a latch81positioned in handle61and moveable along a line82between the locked position at which the latch81engages the radially outward thumb surface66of thumbwheel65, and the unlocked position at which the latch81is out of contact with the radially outward thumb surface66. Lock80also includes a pusher85that is at least partially positioned outside of handle61, but on an opposite side of handle61from the exposed portion of thumbwheel65. The pusher may include a wedge86that engages a post83of latch81. Post83may be oriented perpendicular to the line82of action of latch81. Vascular intervention device delivery system may be enabled by depressing pusher85along line87to move latch81out of contact with radially outward thumb surface66of thumbwheel65.

INDUSTRIAL APPLICABILITY

The present disclosure is generally applicable to vascular intervention device delivery systems, and more particularly to a delivery system for delivery of self expanding stents and other vascular intervention devices with self expanding action. The present disclosure finds specific applicability to delivery of relatively long vascular intervention devices that produce substantial friction on the inner surface of retractable sheath37, and thus require higher forces on retractable sheath37and pull38in order to successfully deliver the vascular intervention device to an intended treatment site.

The vascular intervention device delivery system10,60will typically be packaged in a conventional sterile packaging in a known manner for shipment. After a wire guide (not shown) has been positioned in a patient's body across a treatment location, the catheter30may be slid over the wire guide to position the distal carrier segment32and the attached self expanding stent45at the treatment location within the vessel50of the patient. Thereafter, the wire guide may be withdrawn or left in place. During this portion of the procedure, the thumbwheel65of the vascular intervention device delivery system60may be disabled by maintaining the lock80in its locked position as shown inFIG. 7. After the distal carrier segment32is properly positioned and it is now time to deploy the self expanding stent45, the user may depress pusher85to disengage lock80and move latch81out of contact with the radially outward thumb surface66of thumbwheel65.

A method of operating vascular intervention device delivery system10,60by first pivoting pivot plate from the locked position to the locked position. Next, the thumbwheel15,65is rotated in a reverse direction to wind pull38onto spool17,67to build up tension in the retractable sheath37and pull38without moving the retractable sheath37relative to the distal carrier segment32of catheter30. Next, a portion, which is less than all, of the distal carrier segment32is uncovered by continuing to rotate the thumbwheel15,65in the reverse direction. At some point during the delivery procedure, the user may then pause rotation of the thumbwheel15,65in the reverse direction. For instance, the user may pause in order to confirm that the vascular intervention device, such as a self expanding stent45, is being delivered to the desired location in the vessel50of the patient. While the rotation of the thumbwheel is paused, the user may lift their thumb from the thumbwheel15,65and allow the pivot plate18to pivot from its unlocked position to its locked position under the action of spring21. While the rotation of the thumbwheel15,65is paused, tension in the pull38and the retractable sheath37is maintained by the pivot plate pivoting from the unlocked position to the locked position. This prevents rotation of the thumbwheel15,65in the forward direction. A remaining portion of the distal carrier segment32is then uncovered to facilitate complete deployment of the self expanding stent45by again pivoting the pivot plate18to the unlocked position and resuming rotation of the thumbwheel15,65in the reverse direction until retractable sheath37arrives at its second position fully uncovering distal carrier segment32. Those skilled in the art will appreciate that pivoting of the pivot plate18from the locked position to the unlocked position may be accomplished by pushing thumbwheel15,65into the handle11,61against the action of spring21. Thus, when pressure on thumbwheel15,65is relieved, spring21will urge pivot plate18back to its locked position to prevent further rotation of thumbwheel15,65.

An important aspect of the ratchet operated vascular intervention device delivery system10,60of the present disclosure is to allow for rotation of thumbwheel15,65in one direction only, unless the user permits rotation in the forward direction to intentionally relax tension in pull38and retractable sheath37. This means that the pull38and hence the retractable sheath37are normally only be pulled proximally. If the thumbwheel15,65were to rotate in both directions, it could cause the pull38to slack and possibly jump out of the collection diameter of the spool17,67on thumbwheel15,65. Also, by the user keeping the rotation of thumbwheel15,65to one direction only, ratchet20,70allows all of the energy already placed in the system10,60by the user to be maintained. For example, if the user was to partially deploy a self expanding stent45that had a deployment force of 30 N they will have to put effort into getting the stent to partially deploy. This effort could have caused the sheath37to stretch slightly and also the inner catheter30to compress slightly. If this energy were lost when the thumbwheel15,65were released, it would mean that when the deployment was resumed from that point, the user would have to rotate the thumbwheel15,65an amount in order to reestablish tension in the system10,60again before the self expanding stent45would continue to deploy. This may be especially important in the case of deploying longer stents that require higher forces.