Catheter device with detachable distal end

An atherectomy catheter includes an elongate catheter body, a cutter at a distal end of the catheter body, and a nosecone attached to a distal end of the catheter body. The cutter is configured to excise tissue from the body. The nosecone is configured to hold tissue excised from the cutter. The nosecone includes a distal section, a proximal section, and a connection mechanism that is configured to allow the distal section to attach and detach from the proximal section during use. The distal section includes a plug configured to sit within an inner diameter of the proximal section when the proximal section is connected to the distal section.

INCORPORATION BY REFERENCE

FIELD

This application is related to tissue collection devices that can be used with occlusion-crossing devices or systems such as atherectomy catheters. In particular, described herein are nosecones that can be used with catheter devices where the connection does not interfere with the catheter device cutter and its function of cutting and clearing out debulked tissue.

BACKGROUND

Peripheral artery disease (PAD) affects millions of people in the United States alone. PAD is a silent, dangerous disease that can have catastrophic consequences when left untreated. PAD is the leading cause of amputation in patients over 50 and is responsible for approximately 160,000 amputations in the United States each year.

Peripheral artery disease (PAD) is a progressive narrowing of the blood vessels most often caused by atherosclerosis, the collection of plaque or a fatty substance along the inner lining of the artery wall. Over time, this substance hardens and thickens, which may interfere with blood circulation to the arms, legs, stomach and kidneys. This narrowing forms an occlusion, completely or partially restricting flow through the artery. Blood circulation to the brain and heart may be reduced, increasing the risk for stroke and heart disease.

Interventional treatments for PAD may include endarterectomy and/or atherectomy. Atherectomy offers a simple mechanical advantage over alternative therapies. Removing the majority of plaque mass (e.g., debulking) may create a larger initial lumen and dramatically increases the compliance of the arterial wall. As a result, stent deployment is greatly enhanced.

While atherectomy may provide a minimally invasive solution to clearing the way for placement of stents within initially blocked arteries, there remains a need to improve certain aspects of atherectomy catheters presently available. For example, tissue collection and/or tissue removal from the arteries is a common challenge during atherectomy procedures. One mechanism for handling debulked tissue is to collect the tissue in a distal nosecone or collection chamber of the device. However, removing the tissue from the collection chamber or cleaning the chamber remains difficult. Accordingly, an atherectomy catheter that addresses some of these problems is desired.

SUMMARY OF THE DISCLOSURE

In general, in one embodiment, an atherectomy catheter includes an elongate catheter body, a cutter at a distal end of the catheter body, and a nosecone attached to a distal end of the catheter body. The cutter is configured to excise tissue from the body. The nosecone is configured to hold tissue excised from the cutter. The nosecone includes a distal section, a proximal section, and a connection mechanism that is configured to allow the distal section to attach and detach from the proximal section during use. The distal section includes a plug configured to sit within an inner diameter of the proximal section when the proximal section is connected to the distal section.

This and other embodiments can include one or more of the following features. The nosecone can further include a hollow interior portion configured to receive excised tissue. The nosecone can be flexible. The atherectomy catheter can further include a guidewire channel disposed along an exterior of the nosecone. The guidewire channel can include a distal portion extending along the distal section of the nosecone and a proximal portion extending along the proximal section of the nosecone. The distal portion and proximal portion can be configured to align when the proximal section and the distal section are connected together. The distal portion and proximal portions can be configured to prevent the proximal section and distal sections from rotating relative to one another when a guidewire is placed therethrough. The connection mechanism can further include a tab configured to be gripped through the distal section of the nosecone to rotate the distal section relative to the proximal section to activate or deactivate the connection mechanism. The connection mechanism can further include a cam and ball bearing configured to lock and unlock the proximal section relative to the distal section. The connection mechanism can include a plurality of snap arms configured to extend into the proximal section and to interlock with apertures on the proximal section. The snap arms can each include a tab configured to fit within the apertures. The tabs can be chamfered along a side edge such that rotation of the distal section towards the chamfered edges causes the distal section to automatically unlock from the proximal section. The nosecone can be configured to pivot away from the elongate catheter body to further expose the cutter. The cutter can be configured to move axially into the nosecone to pack tissue.

In general, in one embodiment, an atherectomy catheter includes a catheter body having a catheter body proximal end, a catheter body distal end, a cutting window, a cutter exposable through the cutting window, a nosecone, and a collar. A nosecone has a nosecone proximal end and a nosecone distal end. The nosecone proximal end is configured to couple and decouple from the nosecone distal end. The collar has a collar inner surface configured to maintain a detachable connection between the nosecone proximal end with the nosecone distal end.

This and other embodiments can include one or more of the following features. The nosecone can further include a hollow interior portion configured to receive excised tissue. The atherectomy catheter can further include a locking mechanism for maintaining connection between the nosecone proximal end with the nosecone distal end. The locking mechanism components can be disposed on the nosecone proximal end, the collar, the nosecone distal end, or a combination thereof. The locking mechanism can utilize corresponding threads for mating the detachable nosecone proximal end to the nosecone distal end. The locking mechanism can utilize at least one tab and corresponding aperture for mating the detachable nosecone distal end to the nosecone proximal end. The locking mechanism may not interfere with cutter's ability to extend past the locking mechanism. The nosecone can be rigid. The nosecone can be flexible. The nosecone can include both flexible and rigid regions. The atherectomy catheter can further include a guidewire channel disposed on the nosecone and the catheter body.

In general, an atherectomy catheter includes a catheter body having a catheter body proximal end, a catheter body distal end, a cutting window, a cutter exposable through the cutting window, a nosecone, a collar, and a locking mechanism for maintaining connection between the proximal and distal ends of the nosecone. A nosecone has a nosecone proximal end and a nosecone distal end. The nosecone proximal end is configured to couple and decouple from the nosecone distal end. The collar is configured to maintain connection between the nosecone proximal end with the nosecone distal end. The locking mechanism components are disposed on the nosecone proximal end, the collar, the nosecone distal end, or a combination thereof.

This and other embodiments can include one or more of the following features. The nosecone can further include a hollow interior portion configured to receive excised tissue. The locking mechanism can utilize corresponding threads for mating the nosecone proximal end with the nosecone distal end. The locking mechanism can utilize at least one tab and corresponding aperture for mating the nosecone proximal end with the detachable nosecone distal end. The locking mechanism cannot interfere with the cutter's ability to extend past the locking mechanism. The nosecone can be rigid. The nosecone can be flexible. The nosecone can include both flexible and rigid regions.

In general, an atherectomy catheter includes a catheter body having a catheter body proximal end, a catheter body distal end, a cutting window, a cutter exposable through the cutting window, a nosecone, a collar, and a locking mechanism for maintaining connection between the detachable nosecone and the catheter body. A nosecone has a nosecone proximal end and a nosecone distal end. The nosecone proximal end is configured to couple and decouple from the nosecone distal end. The collar is configured to maintain connection between the detachable nosecone and the catheter body. The locking mechanism includes corresponding threads on the collar, nosecone proximal end, or nosecone distal end adapted to couple the proximal and distal ends of the nosecone.

In general, in one embodiment, an atherectomy catheter includes a catheter body having a catheter body proximal end, a catheter body distal end, a cutting window, a cutter exposable through the cutting window, a nosecone, a collar, and a locking mechanism for maintaining connection between the proximal and distal ends of the nosecone. A nosecone has a nosecone proximal end and a nosecone distal end. The nosecone proximal end is configured to couple and decouple from the nosecone distal end. The collar is configured to maintain connection between the detachable nosecone and the catheter body. The locking mechanism includes at least one tab disposed on the collar having corresponding aperture adapted to mate the proximal and distal ends of the nosecone.

This and other embodiments can include one or more of the following features. The atherectomy catheter can further include a drive system configured to extend and retract the cutter within the nosecone.

DETAILED DESCRIPTION

Described herein are atherectomy catheters including an elongate body, a cutter, and a nosecone configured to collect debulked tissue. The nosecone includes an atraumatic distal end, a proximal end that couples to the remainder of the catheter body, and an interior region for collecting excised tissue. The proximal portion of the nosecone is detachable from the distal portion for ease of for ease of cleaning and/or for quick replacement of the distal portion of the nosecone during an atherectomy procedure.

The nosecones described herein include features that both allow easy coupling of the proximal and distal ends of the nosecone and prevent unwanted decoupling during use. Moreover, the interior surface of the nosecone with detachable distal/proximal portions can be substantially smooth, allowing a cutter to extend therein (e.g., to pack tissue) without hindrance.

The distal end of an exemplary atherectomy catheter1200is shown inFIG. 1A, The atherectomy catheter includes a catheter body1201, a hollow nosecone1204, an annular rotatable cutter1210, and a cutter window1207through which the cutter can debulk tissue. The hollow nosecone1204can be configured to collect tissue as it is removed in the body. Further, in some embodiments, the cutter1210can be moved axially into the nosecone1204to pack tissue therein. Moreover, in some embodiments, the nosecone1204can hinge relative to the catheter body1201, such as at a pivot point. As shown inFIG. 1A, in some embodiments, the nosecone can include holes1244therein for venting. A distal section or end1205of the nosecone1204can be configured to detach from the proximal portion1206of the nosecone1200at attachment/detachment point1226to allow for ease of removing collected or packed tissue. The attachment/detachment point1226can include, for example, one or more coupling elements. Various embodiments of coupling elements are described herein.

FIGS. 1B-1Fshow an exemplary coupling mechanism111that includes a first coupling element925configured to interface with a corresponding coupling element1024for locking and unlocking of the proximal and distal portions of a nosecone (such as nosecone1204).

FIG. 1Dshows the coupling element925, which includes a proximal end930and a distal end928. The coupling element925includes a generally cylindrical main body with a lumen between the proximal and distal ends. The slots or cutouts932a-bare formed through the wall of the main body. Although shown with two slots having a generally rectangular shape, the coupling element925can have any number of slots with any shape. The shape of the main body is designed to be inserted into the corresponding coupling element1024for attachment.

FIGS. 1E and 1Fillustrate the corresponding coupling element1024that is configured to releasably attach to the coupling element925. The corresponding coupling element1024is shape set to the coupling element924such that coupling element925can be inserted into the corresponding coupling element1024to form a snug fit (as shown inFIGS. 1B-1C). The corresponding coupling element1024has an inner wall1038that contacts the outer wall934of the coupling element925when fitted. Further, the corresponding coupling element1024includes protrusions shown as tabs1036a-bthat project from its main body towards the center. In some embodiments, the tabs1036a-bprotrude at an angle towards the center of the main body and are configured to extend into the receiving slots932a-b.

Thus, in operation, the corresponding coupling element1024is placed over the outer wall924of the coupling element925. The proximal end1032of the corresponding coupling element1024is advanced over the distal end928of the coupling element925. Then the corresponding coupling element1024(or the coupling element925) is rotated relative to the other element to align the tabs1036a-bwith the slots932a-b. To lock the coupling elements, an edge of the slots932a-bis slid into the recess1031a-buntil a portion of the main body of the coupling element925is held between a tab surface and the inner wall of the corresponding coupling element1024.FIGS. 1B-1Cshows the corresponding coupling element1024surrounding the coupling element925with tabs1036a-bengaged with slots932a-b. The tabs1036a-bare received through the slots932a-binto an interior of the coupling element925. The edge of the slots932a-bare slid into the recesses1031a-bto hold and lock the lateral orientation of the coupling element925within the corresponding coupling element1024. As shown, rotating the corresponding coupling element counter-clockwise disengages the coupling elements and releases the coupling elements from one another.

FIGS. 2A and 2Bshow variations of the coupling elements shown inFIGS. 1B-1F. For example,FIG. 2Ashows a corresponding coupling element1124with two tabs1136a-band a plurality of apertures1105. In some embodiments, the apertures provide for fluid pressure release.FIG. 2Bshows a coupling element1125having slots1132a-c, e.g., configured to interact with tabs1136a-bofFIG. 2A. Although the coupling elements ofFIGS. 1B-IF and2A-2B are shown with two or three tabs/slots, it is to be understood that any number of mating structures can be used to form the detachable tissue collection devices.

FIG. 3Ashows another embodiment of a nosecone204that can be used with an atherectomy catheter. The nosecone204includes a distal end205that is detachable from a proximal end206at coupling mechanism211. The nosecone distal end205is atraumatic.

The nosecone204further includes a cutting aperture207that allows cutter (e.g., an annular cutter) of the device to be exposed therethrough for cutting and removing tissue. The nosecone proximal end206is configured to couple with the remainder of the catheter body, such as at a connection point202. For example, the catheter body201can be coupled with the nosecone204proximal to the cutting aperture207. In some embodiments, the nosecone204can be connected at a hinge point so as to hinge away from the catheter body.

Referring toFIGS. 3A and 3B, the coupling between the nosecone204distal end205and proximal end206may include a collar211. The collar211, in turn, may be attached permanently to the nosecone proximal end106as shown. The collar211can include a collar aperture212that is able to couple to a corresponding feature (e.g. a tab119or other protrusion) on the proximal end105of the nosecone204. The tab219can be configured to include an amount of flexibility such that a user is able to push the end of the collar211past the tab219to align the tab219and the collar aperture212. The insertion of the distal end205into the collar211can be aided by the angled or beveled distal edge of the collar211.

Once aligned with the collar aperture212, the tab219can be engaged or locked within the aperture212by an extension221on the collar211. The extension221is configured to contact the tab219, causing the tab219to pivot (e.g., at a flexion point) with the proximal end of the tab219moving radially towards the central axis of the collar211and the distal end of the tab219moving radially away from the central axis of the collar211to engage/attach within the collar aperture212and lock the tab219in place. Once the tab219is locked in place, the proximal and distal ends206,205of the nosecone will then be connected and/or locked together. To disengage the collar211from the distal end205of the nosecone204, the user can push on the tab to free the tab from the collar aperture212and slide the collar211axially away from the distal end205of the nosecone204.

In an alternative embodiment, the collar211may be permanently attached to the distal end205of the nosecone204rather than the proximal end206. Here, the proximal end206of the nosecone204may include corresponding features with the collar211including tabs with corresponding apertures that are able to mate, corresponding threads that screw together, etc.

In some other variations, the collar211may be completely detachable from both the nosecone proximal end206and the nosecone distal end205. In this design, the collar211may have two or more coupling features for mating the nosecone proximal end206to the nosecone distal end205. The coupling features on the collar211in this example may also be used to properly align the nosecone proximal end206with the nosecone distal end205. For example, the collar may have tabs that mate with corresponding tab acceptors on both the nosecone distal end205and the nosecone proximal end206for holding the two components together, but in addition, the collar211may also have additions features that aid with ensuring that the nosecone distal end205is properly aligned with the nosecone proximal end206. These additional features may include, but are not limited to, protrusions and corresponding apertures or slots.

Turning toFIGS. 4A-4E, another coupling mechanism310between the distal end305and proximal end306of a nosecone304is shown. The coupling mechanism310for the nosecone304employs a twist type motion to engage and disengage the nosecone distal end305with the nosecone proximal end306. The twist coupling mechanism310is best shown inFIGS. 4C-4E(the collar311has been removed in these figures for clarity). The twist coupling mechanism310includes a hooked, curved, or c-shaped extension315on the distal end305that interlock or mates with a corresponding hooked, curved, or c-shaped extension316on the proximal end306when the proximal and distal ends306,305are rotated relative to one another. Each extension315,316includes a wave-like curve or bump326,325that fits with the corresponding bump326,325on the opposite side. To connect the proximal and distal portions306,305, the two portions can be rotated relative to one another. To release, they can be rotated in the opposite direction.

Referring back toFIGS. 4A-4B, the collar311can be clamped over the twist mechanism310to keep the extensions315,316from rotating apart during use. The collar311can be permanently attached to either the proximal end (as shown inFIGS. 3A-3B) or the distal end. When attached to the proximal end, the collar311can have a beveled or angled distal edge to aid in insertion of the distal end305therein.

Another exemplary embodiment of a nosecone504is shown inFIGS. 5A-5H. As shown inFIG. 5A, the nosecone504includes a proximal end506and a detachable distal end505. The nosecone504further includes a coupling mechanism515configured to allow for attachment and detachment of the distal end505of the nosecone504. Referring toFIGS. 5B and 5G, the coupling mechanism515includes a solid plug571that fits within, and seals to, the inner diameter of the proximal end506of the nosecone504. The coupling mechanism515further includes an annular collar573configured to permanently attach to the proximal end505of the nosecone. The coupling mechanism515connects together by twisting a rotatable tab525(which is fixed to the collar573) to activate a cam577. When the distal end505is locked to the proximal end506(as shown inFIGS. 5C and 5D), a ball bearing527sits within an outer window533. When unlocked, however, the ball bearing525is pulled back inside the window533into the inner slot531(as shown inFIGS. 5E-5F).

In use, the user can grab the tab525(e.g., through a flexible portion of the distal end505), insert the plug571into the distal end505, and rotate the tab525. As shown inFIG. 5G, doing so will cause the peak in the cam577to push the ball527from the window531towards the window533. Once engaged in the window533, the ball527will prevent future movement of the proximal and distal ends506,507relative to one another. To unlock, the user can rotate the tab525in the opposite direction. This will cause the ball527to move all the way back into the inner window531, allowing the distal end505to be pulled distally away from the proximal end506.

The coupling mechanisms515is positioned close to the distal tip of the nosecone504(e.g., 1-2 inches, such as approximately 1.5 inches away from the distal edge of the cutting window507). This can advantageously provide for ample room for tissue packing inside the proximal portion506and prevent interference of the coupling mechanism515with the cutter as it packs tissue.

Another exemplary embodiment of a nosecone604is shown inFIGS. 6A-6C. The nosecone604includes a proximal end606and a detachable distal end605. The nosecone604further includes a coupling mechanism622configured to allow for attachment and detachment of the distal end605from the proximal end606. The coupling mechanism622includes a solid plug671that fits within, and seals to, the inner diameter of the proximal end606of the nosecone. The coupling mechanism622further includes two snap arms623a,bthat extend proximally away from the plug671. The snap arms623a,bcan further include radially extending tabs625a,bthat are configured to snap into corresponding snap window624a,bon the proximal end606. In some embodiments, the user can release the distal end605by pushing on the tabs625a,b. Further, in some embodiments, the tabs625a,bcan be chamfered at one edge such that either clockwise or counterclockwise rotation can automatically push the tabs625a,bto release the coupling mechanism622.

Again, the coupling mechanism622is positioned close to the distal tip of the nosecone604(e.g., there can be about 1-2 inches, such as 1.5 inches, from a distal edge of the cutter window607to a proximal end of the snap arms). This can advantageously provide for ample room for tissue packing inside the proximal portion606and prevent interference of the coupling mechanism622with the cutter as it packs tissue.

Referring toFIG. 7, in any of the embodiments described herein, a guidewire lumen755can extend down the side of the nosecone. The guidewire lumen755can include two interconnectable sections (one section attached to the proximal end706and another section attached to the distal end705). Insertion of the guidewire through the lumen755can help keep the proximal and distal ends706,705of the nosecone together. That is, the insertion of the guidewire through the lumen755can help prevent rotation of the proximal and distal ends706,705relative to one another when a rotatable or twisting locking mechanism710is used to unlock (e.g., any of the embodiments described herein that include twisting or rotation to unlock).

In some embodiments, features on both the nosecone distal end and the nosecone proximal end may aid a user in properly aligning the nosecone proximal end with the nosecone distal end. For example, in some instances, the nosecone proximal end and the nosecone distal end may be angled or biased such that they fit together. To further ensure proper alignment or attachment of these two components, the nosecone proximal end and the catheter distal end may further include features on the angled or biased end surfaces that are configured to mate. In other examples, there may be visual indicators on the nosecone proximal end and the catheter body distal end that aid a user in aligning the two portions.

In some embodiments, the attachment features can include an auditory or physical signal that indicates that the proximal and distal ends of the nosecone are connected (e.g., the detent feature can make a clicking noise to signal locking).

In some embodiments, the attachment mechanisms and distal ends of the nosecones described herein can be reusable. In other embodiments, the distal end of the nosecone is meant as a single use, and the attachment mechanisms cannot be detached and then reattached. For example, the tab features can be configured to break or become unusable after disengaged.

The attachment mechanisms shown with respect toFIGS. 3A-6Chave a substantially smooth inner circumference (i.e., on the inside of the nosecone) and are free of tabs or mechanisms that extend radially inwards into the nosecone. This can advantageously prevent the attachment mechanisms from interfering with the movement of the cutter as it is moved into the nosecone (i.e., for packing) and/or prevent pieces of excised plaque or tissue from becoming entangled on radially inwardly protruding extensions of the attachment mechanisms.

In some embodiments, the nosecone attachment mechanisms described herein are a set distance from the cutting window to further eliminate interference with the cutter. Thus, the distance between the attachment mechanism and the cutting window can be, for example, 0.5″-1.0″, such as 0.6″-0.8″, such as approximately 0.68″ or 0.70″. In some embodiments, the distal edge of the cutter, when fully extended, can be positioned just proximal of the attachment mechanisms.

It should be understood that any suitable mechanism or means (e.g. friction fit, mated fit, threaded fit, hooks, securing members, etc.) may be used in addition to, or in place of, the attachment mechanisms described herein to detach a portion or the entirety of a tissue collection device to another device.

Additionally, any suitable materials such as nitinol, stainless steel (e.g. grade304), or titanium or alloys may be used to form the attachment mechanisms. Coatings including gold or platinum may be used to promote radiopacity.

Any of the features of the described tissue collection devices can be used in combination without departing from the disclosure.

Having a nosecone with detachable sections therein can advantageously be used for flushing or otherwise clearing excised tissue out of the nosecone. That is, after tissue has been excised and collected in the nosecone (such as by packing it into the nosecone through axial movement of the cutter), the distal end or section of the nosecone can be removed, thereby permitting the proximal end to be flushed (e.g., from the cutting window through the open distal end) and/or allowing either the proximal or the distal end to be easily cleared with a tissue removal tool.

Although the above coupling mechanisms have been described as being used to attach and detach to portions of a nosecone, they can also be used to couple other portions of a catheter. For example, in some embodiments, the entire tissue-collection portion of the nosecone can be removable from the rest of the catheter using one of the coupling mechanisms described herein.

Any of the described tissue collection devices can be used with atherectomy or other occlusion crossing devices. In such cases, the atherectomy devices typically include an elongate body and a rotatable tip (with a cutter) at the first distal end of the elongate body and configured to rotate relative to the elongate body. Such devices are described in U.S. Patent Application No. 61/646,843, titled “ATHERECTOMY CATHETERS WITH IMAGING,” filed on May 14, 2012, U.S. patent application Ser. No. 13/433,049, titled “OCCLUSION-CROSSING DEVICES, IMAGING, AND ATHERECTOMY DEVICES,” filed Mar. 28, 2012, U.S. patent application Ser. No. 13/175,232, titled “ATHERECTOMY CATHETERS WITH LONGITUDINALLY DISPLACEABLE DRIVE SHAFTS,” filed on Jul. 1, 2011, U.S. patent application Ser. No. 12/829,277, titled “ATHERECTOMY CATHETER WITH LATERALLY-DISPLACEABLE TIP,” filed on Jul. 1, 2010, and U.S. patent application Ser. No. 12/829,267, titled “CATHETER-BASED OFF-AXIS OPTICAL COHERENCE TOMOGRAPHY IMAGING SYSTEM,” filed on Jul. 1, 2010, International Patent Application No. PCT/US2015/014613, titled “ATHERECTOMY CATHETERS AND OCCLUSION CROSSING DEVICES,” filed on Feb. 5, 2015, U.S. patent application Ser. No. 15/072,272, titled “ATHERECTOMY CATHETERS DEVICES HAVING MULTI-CHANNEL BUSHINGS,” filed on Mar. 16, 2016, and U.S. patent application Ser. No. 15/076,568, titled “ATHERECTOMY CATHETERS AND OCCLUSION CROSSING DEVICES,” filed on Mar. 21, 2016, all of which are herein incorporated by reference in their entirety.