CLOT RETRIEVAL SYSTEM FOR REMOVING OCCLUSIVE CLOT FROM A BLOOD VESSEL
A clot capture catheter having an outer inflatable expansile member and an inner inflatable expansile member positioned within the outer inflatable expansile member at a distal end of a shaft of the catheter is presented herein. The inner and outer inflatable expansile members can have differing compliance than each other. Inflation of a higher compliance inner inflatable expansile member can cause a lower compliance outer inflatable expansile member to shorten and provide tension to the distal end of the shaft to case the distal end to open to a funnel shape. Inflation of a lower compliance inner inflatable expansile member can center the distal end of the shaft within a vessel, and inflation of a higher compliance outer inflatable member can provide atraumatic flow arrest to the vessel.
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This application is divisional of U.S. application Ser. No. 16/326,030 filed Feb. 15, 2019, which is a United States national stage entry of an International Application No. PCT/EP2017/069668 filed Aug. 3, 2017, which claims priority to European Patent Application No. 16186028.3 filed Aug. 26, 2016 and U.S. Provisional Application No. 62/376,264 filed Aug. 17, 2016. The contents of these applications are incorporated herein by reference in their entirety as if set forth verbatim.
FIELD OF THE INVENTIONThis invention relates to devices intended for use in procedures involving removing acute blockages from blood vessels. Acute obstructions may include clot, misplaced devices, migrated devices, large emboli and the like. Thromboembolism occurs when part or all of a thrombus breaks away from the blood vessel wall. This clot (now called an embolus) is then carried in the direction of blood flow. An ischemic stroke may result if the clot lodges in the cerebral vasculature. A pulmonary embolism may result if the clot originates in the venous system or in the right side of the heart and lodges in a pulmonary artery or branch thereof. Clots may also develop and block vessels locally without being released in the form of an embolus—this mechanism is common in the formation of coronary blockages. The invention is particularly suited for use in cases involving the removal of clot from cerebral arteries in patients suffering acute ischemic stroke (AIS), from coronary native or graft vessels in patients suffering from myocardial infarction (Ml), and from pulmonary arteries in patients suffering from pulmonary embolism (PE) and from other peripheral arterial and venous vessels in which clot is causing an occlusion.
BACKGROUNDRecent clinical studies have shown that mechanical thrombectomy is a very effective method of restoring blood flow to the ischemic tissue of patients who have recently suffered an acute ischemic stroke. This procedure typically involves advancing a thrombectomy device (which may be a stent-retriever and/or an aspiration catheter) to the occlusive clot, engaging with the clot and retracting the clot into the safety of a local aspiration catheter or a more proximally placed guide or sheath. In the latter case a balloon guide catheter is often employed, as with such a catheter the balloon can be inflated to restrict flow past the catheter, which makes it easier to safely retrieve the captured clot into the catheter mouth. Aspiration through the balloon guide catheter is typically used to reverse flow in the distal vasculature and assist the passage of the captured clot into the catheter mouth.
However, despite the benefits provided by balloon guides, there are significant limitations to currently available devices:
One of these limitations is due to the location of the balloon on the catheter. Conventional balloon guide catheters have a “dead space” distal to the balloon because of the manner in which the distal neck of the balloon is attached to the catheter shaft and because of the presence of a distal catheter tip. This dead space is a region from which clot cannot easily be aspirated or sucked, and thus if clot fragments become lodged in this region they may escape distally upon deflation of the balloon (which must be done prior to removal of the catheter from the patient), potentially causing occlusion of a blood vessel and serious patient harm.
A second limitation of conventional balloon guide catheters is the level of shear stress induced in the clot as it withdrawn into the catheter. This stress is influenced by a number of factors, including the relative size of the clot and catheter lumen and the coefficient of friction of the clot relative to the catheter. The clot entering the catheter must abruptly change in shape to conform to the inner diameter of the catheter in order to enter the catheter. This abrupt change can create a high shear stress at the interface between clot and catheter tip, which can result in shearing or tearing of the clot, releasing clot fragments which may then hang up in the previously mentioned dead space, or causing large portions or the entirety of the clot to be dislodged from the stentretriever or aspiration catheter which has retracted it to the balloon guide catheter. If these clot portions or fragments are not then aspirated fully into the balloon guide catheter they may travel distally and cause injury or death.
STATEMENTS OF THE INVENTIONThis invention solves the previously described problems of clot shear and clot fragments lodging in the “dead space” at the distal tip of a balloon guide catheter. The subject of this invention is a catheter configured for use in a mechanical thrombectomy procedure comprising an elongate tubular shaft with an expandable distal tip portion.
The elongate shaft comprises a first inner lumen through which other catheters or components may be passed and through which clot may be aspirated, and a second inner lumen within the wall of the shaft running from the proximal hub of the catheter to an inflatable member at the distal end of the shaft. This second inner lumen may be circular in cross section, or may be oblong, and may comprise multiple lumens.
One embodiment of the expandable distal tip portion comprises a funnel shaped balloon and has a collapsed and an expanded state. In the collapsed state the balloon is deflated and may be folded and/or pleated in order to minimize its profile for advancement through an introducer sheath and through the vasculature of the patient. In the expanded state the balloon is inflated. Inflation of the balloon serves a number of purposes:
- 1) The balloon can be inflated to a diameter that brings it into contact with the vessel wall, thus partially or completely preventing blood flow past the balloon. This in tum may help to reduce the likelihood of some or all of the clot being retrieved into the catheter during a thrombectomy procedure. This also facilitates effective aspiration through the catheter, ensuring that this aspiration creates reverse flow in the distal vessel.
- 2) Inflation of the balloon can help to stabilize the catheter within the vessel, preventing unintended catheter movement and consequent vessel trauma.
- 3) Inflation of the balloon of this invention also changes the shape of the catheter tip, optimizing the geometry of the interface between the catheter tip and any material or devices being withdrawn into it. In particular this shape change reduces the shear forces exerted on thrombus material as it is withdrawn into the catheter, and minimizes or eliminates any “dead space” or pocket in which thrombus might be caught.
In one embodiment of this invention the funnel shaped balloon is integral to the distal catheter tip portion and is formed from a length of polymer tubing which is inverted so that the distal junction between the balloon and catheter sits under (and within) the balloon itself.
The balloon wall thickness may be profiled/tapered in order to force the balloon to preferentially expand more in certain areas than in others, thus enabling a funnel shaped profile to be attained upon inflation. In one embodiment the wall thickness of the proximal and distal portions of the balloon is greater than that of the middle section. In another embodiment the wall thickness of the proximal portion of the balloon is greater than that of the middle and distal sections.
In another embodiment a proximal portion of the balloon is reinforced in order to limit its expansion when inflated, thus causing preferential expansion of the distal portion of the balloon and creating a bulbous funnel shape at the distal end. This reinforcement may be in the form of ribs, which may run axially or radially along the balloon, and/or may be formed from the same or a different material to the balloon itself.
The inverted balloon may be positioned such that it overhangs the catheter tip, in which case the balloon material is not under any axial tension in the unexpanded state, unlike most conventional compliant balloons. This lack of axial tension combined with a degree of overhang (ideally greater than 0.5 mm but less than 3.5 mm) is key to ensuring the balloon can inflate to a funnel-like shape.
The balloon may be pre-formed into a funnel-like shape prior to assembly onto the catheter shaft, in which case it may be beneficial to also provide it with pleats or preferential fold lines in order to facilitate efficient wrap down to a low profile.
In one series of embodiments multiple balloons are employed on the catheter shaft. This has the benefit of allowing individual balloon properties to be tailored for specific tasks. For example a low pressure, compliant, balloon may be designed to seal against the vessel wall to help create flow arrest, while another balloon may be designed to adopt a funnel-like shape at the distal catheter tip to minimize shear forces on the clot and facilitate easy entry of large and/or firm clots into the catheter mouth. In some cases a higher pressure, less compliant, balloon may be employed to help keep the catheter tip from lying too close to the vessel wall and impeding clot retrieval.
The materials used in the construction of this catheter must be carefully selected. For high pressure balloons relatively high modulus materials such as PET or Polyamide make good choices, but for certain inflatable portions of the catheters of this invention a much softer more compliant material is desired. This preferably comprises an amorphous elastomeric polymer, so that it can be stretched/strained under inflation pressure to a diameter at least twice and as much as 5 times its uninflated diameter and recover most or all of its unexpanded shape upon deflation. This requires the material to withstand an elastic strain of at least 200% and ideally 500% or more with minimal levels of plastic deformation. Recoverable strains of such a high level are greatly facilitated by crosslinking of the polymer chains, and hence thermoset materials such as silicone rubbers may be a good choice for a compliant balloon. However silicone is not an easy material to join to a second material as it cannot easily be melted and made miscible with another material to form a strong and low profile weld joint for example. For this reason polyurethane elastomers are a preferred material for the balloon of this invention. In particular thermoplastic polyurethane elastomers would make an ideal material as this can be melted as part of a welding or joining process, or can be solvent bonded or adhesively bonded. In addition such polyurethanes can be joined to compatible families of materials in order to create a greater stiffness gradient along the length of the catheter than would be possible if limited to polyurethanes alone. For example, a very soft polyurethane can be used for the balloon and very distal section of the catheter; one or more Pebax (polyether block amide copolymer) materials may be used for a mid-section of the catheter; and polyamide material(s) may be used for the proximal section of the catheter shaft. This series of materials offers increasingly higher durometers and Young's modulus (or stiffness), so that a very flexible distal shaft region can be smoothly transitioned to a much stiffer proximal shaft region. The Polyether block amide material has the advantage of being joinable to both the Polyurethane and the Polyamide, even though the Polyurethane and the Polyamide are not so easily joined to one another.
In one aspect the invention provides a clot capture catheter comprising an elongate tubular shaft having a proximal end, a distal end and an inflatable expansile member at the distal end, the expansile member being inflatable from a collapsed delivery configuration to an expanded configuration, wherein, in the expanded configuration, the expansile member extends to at least the distalmost tip of the shaft and extends radially outwardly from the shaft at the distalmost tip of the shaft to define a mouth.
In one aspect the invention provided a clot capture catheter comprising an elongate tubular shaft having a proximal end, a distal end and an inflatable expansile member at the distal end, the expansile member being inflatable from a collapsed delivery configuration to an expanded configuration, wherein, in the expanded configuration, the expansile member extends radially outwardly at the distalmost tip of the catheter to define a funnel shaped profile having an enlarged distal clot entry mouth.
In one embodiment, in the expanded configuration, the diameter of the distalmost portion of the catheter defined by the expansile member is larger than the diameter of the generally cylindrical inner lumen of the distal region of the catheter.
In one case, in the expanded configuration, the expansile member extends distally beyond the distalmost tip of the shaft.
In one embodiment the expansile member comprises a balloon. The balloon, in the expanded configuration, may be of funnel shape having an enlarged distal entry mouth and a narrower proximal end.
In one case the balloon is integral to the distal tip of the catheter shaft.
The expansile member may be formed from a polymeric tube which is inverted so that a distal junction between the balloon and the catheter shaft is located within the balloon.
In one embodiment the balloon comprises regions which have different properties to one another.
The balloon may comprise a proximal region, a distal region and a median region between the proximal and distal regions and wherein, in the expanded configuration, the distal region expands to a greater extent than the proximal region.
In one case at least one region has a different wall thickness than at least one other region.
In one case the wall thickness of the proximal and distal regions is greater than the wall thickness of the median region.
In one embodiment the wall thickness of the proximal region is greater than the wall thickness of the median region and the distal region.
In one case the expansile member comprises a proximal neck and a distal neck, the proximal neck having a first thickness, and being connected to the catheter shaft proximal of the distal end of the catheter, a proximal portion of the expansile member comprising a second thickness, a distal portion of the expansile member comprising a third thickness, and the distal neck, which is inverted and joined to the distal end of the catheter shaft, comprising a fourth thickness.
In one embodiment a mid-portion of the expansile member comprises a variable thickness which tapers from the second thickness to the third thickness.
In one case the first thickness is greater than the second thickness, and the second thickness is greater than the third thickness.
In one embodiment the fourth thickness is greater than the third thickness. In one case the fourth thickness is greater than the first thickness.
In one embodiment the first thickness is approximately the same as the second thickness in the deflated state, but is greater than the second thickness in the inflated state.
In one case a band is provided between the proximal and distal regions of the expansile member, the band having a greater wall thickness than the wall thickness of the proximal and/or distal region, to create a relatively non-expansile region such that the expansile member preferentially inflates proximal and distal of the band to provide a funnel shape profile.
In one case at least one of the regions is reinforced to limit the expansion of that region.
In one embodiment the proximal region comprises a reinforcement.
In one case the reinforcement comprises ribs.
The ribs may extend axially and/or radially along at least a portion of the proximal region.
In one embodiment the ribs are of the same or a different material than that of the balloon.
In one case the expansile member in the collapsed configuration extends beyond the distal tip of the catheter shaft.
The expansile member may extend beyond the distal tip of the catheter shaft for a distance of from 0.5 mm to 3.5 mm.
In one embodiment the catheter shaft comprises a main inner lumen, and an inflation lumen for inflating the expansile member.
The inflation lumen may extend within the wall of catheter shaft.
In one case the inflation lumen and the catheter lumen are eccentric.
In a further case the inflation lumen and the catheter lumen are concentric.
In one case the inflatable expansile member comprises an amorphous elastomeric polymer.
The elastomeric polymer may be a thermoplastic polyurethane elastomer.
In one embodiment a portion of the shaft of the catheter comprises the inflatable expansile member.
In one case a distal region of the catheter shaft comprises an amorphous elastomeric polymer.
In one embodiment the amorphous elastomeric polymer of the distal region of the catheter is a thermoplastic polyurethane elastomer.
In one case a distal portion of the shaft comprises a first amorphous elastomeric polymer and the inflatable expansile member comprises a second amorphous elastomeric polymer which is different than the first amorphous elastomeric polymer
In one embodiment the catheter shaft comprises a proximal region, a distal region and a median region between the proximal region and the distal region and wherein the proximal, the median and the distal regions of the shaft comprise materials with differing stiffness.
In one case the proximal region of the catheter shaft comprise a polyamide, the distal region comprises a thermoplastic polyurethane elastomer and the median region comprises a polyether block amide copolymer.
In one case the catheter further comprises an expansile marker band at or adjacent to the expansile member.
In one embodiment the distal marker band is located beneath the expansile member.
In one case the radiopaque distal marker is of generally tubular shape having axially extending slots which are configured to facilitate expansion of the marker.
In one embodiment the clot capture catheter comprises two to more expansile members.
In a further embodiment at least some of the expansile members have differing compliance.
In one case a clot capture catheter comprises inflatable balloon members mounted on the distal section of the catheter, the balloon member comprising an inner balloon members positioned within an outer balloon.
In one embodiment the elastic compliance of the balloon members are different.
In one case only the inner balloon communicates with an inflation lumen facilitating expansion.
In one embodiment the inner balloon is configured to contact the outer balloon, on expansion.
In one case, in the expanded configuration, an effective diameter of the distal-most portion of the expansile member is at least 20%, greater than the diameter of the inner lumen at the distal end of the catheter shaft.
In another case the effective diameter is at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100% greater than the diameter of the inner lumen at the distal end of the catheter shaft.
In one embodiment the distal tip region of the expansile member is flared outwardly from the catheter shaft lumen at an opening angle.
In one case the opening angle is from 10 to 60 degrees, or from 15 to 45 degrees.
In one embodiment the expansile member comprises features such as an undulation and/or a fold to assist in flaring of the distal tip region.
In one case the inflatable member is inverted and joined to the catheter shaft at a proximal joint area and wherein the shaft comprises multiple layers, including an outer sleeve, a middle layer, an inner liner, and a reinforcing braid or coil.
In one embodiment the proximal end of the inflatable member is joined to the elongate shaft at proximal joint area and the other end of the inflatable member is inverted and joined to the middle layer at a junction such that the middle section of a generally tubular polymer member that forms the expansile member is positioned at the distal end of the catheter, and the portion of the tubular polymer member that lies between the junction and the middle section is joined to the distal section of the catheter shaft.
In one case a strip of material is mounted over the expansile member and joined proximally to the catheter body and the distal end of the material strip is bonded to the atraumatic distal catheter tip.
In one embodiment a plurality of material strips are positioned radially around the balloon.
In one case the material strip comprises a low elastic compliance polymer such as PET.
In one embodiment the expansile element is of composite construction comprising semi-rigid ribs interspersed with sections of elastic expansile material.
In one case the ribs extend parallel to the axis of the catheter. The ribs may extend in a spiral configuration.
In one embodiment the catheter comprises a sealed inflation chamber which is adapted to be filled with a radiopaque fluid.
In one case a clot capture catheter comprises a plunger for inflating the expansile member and deflating the expansile member.
In another case a clot capture catheter comprises a controller for moving the plunger to control the inflation and deflation of the expansile member.
The controller may comprise a manual knob.
In one embodiment the plunger is defined by a corrugated body.
In one case a clot capture catheter comprises a spring to bias the movement of the corrugated body.
In one embodiment the profile of the distal tip of the expansile member m the expanded configuration is of non-uniform shape.
In one case the profile comprises an ellipse.
In one embodiment a kit comprises a clot capture catheter, a clot engaging device and a microcatheter for the clot engaging device.
The clot engaging device is a stent-retriever device.
In another aspect the invention provides clot capture procedure comprising:
- providing a clot capture catheter having an inflatable member at the distalmost tip of the catheter;
- with the inflatable member m a collapsed configuration, advancing the clot capture catheter towards a clot; inflating the inflatable member at the distal tip of the catheter so that the inflatable member extends outwardly from the distalmost tip of the catheter to the vessel wall; drawing the clot into the catheter;
- deflating the inflatable member; and
- withdrawing the catheter.
In one case the method comprises aspirating to draw the clot into the catheter. Alternatively or additionally, the method comprises engaging the clot with a mechanical device such as a stent-retriever to draw the clot into the catheter.
In one embodiment a clot capture procedure comprises providing a microcatheter, advancing the microcatheter through the clot capture catheter, and deploying the clot engaging device from the catheter.
In another aspect the invention provides a method for capturing clot comprising:—advancing a catheter through the vasculature to a position proximal of the target clot in a vessel; crossing the clot with a microcatheter; advancing a clot capture device through the microcatheter to the site of the clot;
- retracting the microcatheter to deploy the clot capture device at least partially beneath the clot;
- inflating the expansile member of the catheter to slow or stop flow in the vessel; retracting the clot capture device proximally towards the catheter;
- connecting a syringe or pump to the proximal end of catheter and aspirating to reverse blood flow in the vessel;
- retracting the clot capture device and captured clot under aspiration into the mouth of the catheter;
- continuing to retract the clot capture device under aspiration through and out of the catheter; and
- discontinuing aspiration and deflating the expansile member in order to restore blood flow to vessel.
The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:
Specific embodiments of the present invention are now described in detail with reference to the Figures, wherein identical reference numbers indicate identical or functionality similar elements. The terms “distal” or “proximal” are used in the following description with respect to a position or direction relative to the treating physician. “Distal” or “distally” are a position distant from or in a direction away from the physician. “Proximal” or “proximally” or “proximate” are a position near or in a direction toward the physician.
Accessing cerebral, coronary and pulmonary vessels involves the use of a number of commercially available products and conventional procedural steps. Access products such as guidewires, diagnostic catheters and microcatheters are described elsewhere and are regularly used in cath lab procedures. It is assumed in the descriptions below that these products and methods are employed in conjunction with the device and methods of this invention and do not need to be described in detail.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description of the invention is in many cases in the context of treatment of intracranial arteries, the invention may also be used in other body passageways as previously described.
The inflatable portion 101 of the distal tip preferably comprises an amorphous elastomeric polymer, so that it can be stretched/strained under inflation pressure to a diameter at least twice and as much as 5 times its uninflated diameter and recover most or all of its unexpanded shape upon deflation. This requires the material to withstand an elastic strain of at least 200% and ideally 500% or more, ideally with minimal levels of plastic deformation or hysteresis.
Recoverable strains of such a high level are greatly facilitated by crosslinking of the polymer chains, and hence thermoset materials such as silicone rubbers may be a good choice. However silicone is not an easy material to join to a second material as it cannot easily be melted and made miscible with another material to form a strong and low profile weld joint for example. For this reason polyurethane elastomers are also a suitable material for the balloon of this invention. In particular thermoplastic polyurethane elastomers would make ideal materials as these can be melted as part of a welding or joining process, or can be solvent bonded or adhesively bonded.
The inflation lumen may be formed in a number of different ways as will be described later, and may be lined with a material or materials (such as PTFE, PEP, PET or Polyimide for example), of a higher melting point or softening point to that of the main wall of the shaft in order to facilitate formation of the inflation lumen and subsequent removal of any forming mandrels used in that process. The shaft may be eccentric in design as shown in
The critical feature of this profile is that the effective diameter 311 of the distal-most portion of the catheter is significantly greater than the diameter 312 of the generally cylindrical inner lumen of the distal region of the catheter. Conventional clot retrieval catheters may have some rounding or chamfering of their distal tips to create a very minor lead-in, but this has minimal effect of reducing the shear stress on clot and avoiding fragment loss. The invention disclosed creates a genuine funnel shape without the need for a pull-wire or other such stiff and bulky mechanical actuation. The funnel created is such that diameter 311 is ideally at least 20% greater than diameter 312, and preferably 50% or 100% greater than diameter 312. Thus if diameter 312 is 0.084″ as might be the case for a typical catheter of this type, then diameter 311 is at least 0.101″ and is ideally as much as 0.126″ or 0.168″ or more.
The wall thickness profile of the inflatable member 301 is very similar to that of inflatable member 400 of
In
In each of these embodiments the wall thickness of the thinner walled sections decreases by a greater % upon inflation than does the wall thickness of the thicker walled sections, which enables the uninflated wall thickness to be used to control the inflated shape of the inflatable member.
- Using conventional endovascular access techniques to advance the balloon guide catheter 703 (or similar guide or sheath) through the vasculature to a position proximal of the target clot;
- Crossing the clot with a microcatheter, usually with the aid of a guidewire;
- Advancing a stent-retriever through the microcatheter to the site of the clot;
- Retracting the microcatheter to deploy the stent-retriever at least partially beneath the clot;
- Inflating the balloon 704 of the balloon guide catheter 703 in order to slow or stop flow in the vessel 700;
- Retracting the stent-retriever proximally towards the balloon guide catheter;
- Connecting a syringe or pump to the proximal end of balloon guide catheter 703 and aspirating in order to reverse blood flow in vessel 700;
- Retracting the stent-retriever and captured clot under aspiration into the mouth 705 of the balloon guide catheter 703;
- Continuing to retract the stent-retriever under aspiration through and out of the balloon guide catheter 703;
- Discontinuing aspiration and deflating balloon 704 m order to restore blood flow to vessel 700.
Any suitable clot capture device can be used as part of the kit and the procedures described herein. The clot capture device may be of a stent-retriever type. The clot capture device may be as described in any of our WO2012/120490A, WO2014/139845A, WO2016/083472A and/or WO2017/089424A.
Preparation port 1311 and sealing cap 1312 are used to evacuate, fill and seal the unit prior to use. In a preferred embodiment these steps are performed by the manufacturer and the unit is provided to the customer ready for use.
In an alternative embodiment these steps of evacuating, prepping and sealing may be done by a second operator (such as a cath lab nurse or technician or fellow) prior to use of the device by a first operator.
It will be apparent from the foregoing description that while particular embodiments of the present invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. For example, while the embodiments described herein refer to particular features, the invention includes embodiments having different combinations of features. The invention also includes embodiments that do not include all of the specific features described.
The invention is not limited to the embodiments hereinbefore described which may be varied in construction and detail.
Claims
1. A clot capture catheter comprising an elongate tubular shaft having a proximal end, a distal end, an outer inflatable expansile member at the distal end, and an inner inflatable expansile member positioned within the outer inflatable expansile member at the distal end,
- wherein the outer inflatable expansile member has a differing compliance than the inner inflatable expansile member, and
- wherein the inflatable expansile members are inflatable from a collapsed delivery configuration to an expanded configuration.
2. The catheter of claim 1, wherein, in the expanded configuration, the outer inflatable expansile member extends to at least a distalmost tip of the elongate tubular shaft and extends radially outwardly from the elongate tubular shaft at the distalmost tip of the elongate tubular shaft to define a mouth.
3. The catheter of claim 1, wherein expansion of the inflatable expansile members applies tension to a distalmost tip of the elongate tubular shaft, thereby causing a distal portion of the elongate tubular shaft to form a funnel shape.
4. The catheter of claim 1, wherein only the inner inflatable expansile member communicates with an inflation lumen facilitating expansion.
5. The catheter of claim 1, wherein the inner inflatable expansile member is configured to contact the outer inflatable expansile member, on expansion.
6. The clot capture catheter of claim 1, wherein the compliance of the outer inflatable expansile member causes a length of the outer inflatable expansile member to shorten as the outer inflatable expansile member expands radially.
7. The clot capture catheter of claim 6, wherein the compliance of the outer inflatable expansile member is less than the compliance of the inner inflatable expansile member.
8. The clot capture catheter of claim 6, wherein the outer inflatable expansile member pulls a distal tip of the distal end of the clot capture catheter to move the distal end into a funnel shape as the length of the outer inflatable expansile member shortens.
9. The clot capture catheter of claim 1, wherein the compliance of the outer inflatable expansile member and/or the compliance of the inner inflatable expansile member differs from a circumferential direction to a longitudinal direction parallel to a catheter axis to facilitate preferential expansion of the outer inflatable expansile member and/or the inner inflatable expansile member during inflation.
10. The clot capture catheter of claim 1, wherein a bond between the outer inflatable expansile member and the distal end of the clot capture catheter is positioned at or near a distal tip of the shaft.
11. The clot capture catheter of claim 1, wherein the inner inflatable expansile member and the outer inflatable expansile member communicate with inflation lumens facilitating individual inflation of the expansile members.
12. The clot capture catheter of claim 1, wherein the compliance of the outer inflatable expansile member is lower than the compliance of the inner inflatable expansile member.
13. The clot capture catheter of claim 12, wherein the compliance and diameter of the inner inflatable expansile member is configured to at least partially self-center the distal end of the catheter in a tubular vessel in the expanded configuration.
14. The clot capture catheter of claim 12, wherein the compliance of the outer inflatable expansile member is configured to provide atraumatic occlusion and flow arrest of a vessel.
15. The catheter of claim 1, wherein the outer inflatable expansile member is formed from a polymeric tube which is inverted so that a distal junction between the outer inflatable expansile member and the elongate tubular shaft is located within the outer inflatable expansile member.
16. The catheter of claim 1, wherein the inflatable expansile members comprise of a proximal region, a distal region and a median region between the proximal and distal regions and wherein, in the expanded configuration, the distal region expands to a greater extent than the proximal region.
17. A clot capture procedure, comprising:
- advancing a clot capture catheter through vasculature to a position proximal of a target clot in a vessel, the clot capture catheter comprising a shaft, an inner inflatable expansile member, and an outer inflatable expansile member; and
- inflating the inner inflatable expansile member of the clot capture catheter to cause the outer inflatable expansile member to expand radially and shorten longitudinally to provide tension to a distal portion of the shaft and expand the distal portion of the shaft to a funnel shape.
18. The clot capture procedure of claim 17, wherein the outer expansile member expands radially solely due to inflation of the inner inflatable expansile member.
19. A clot capture procedure, comprising:
- advancing a clot capture catheter through vasculature to a position proximal of a target clot in a vessel, the clot capture catheter comprising a shaft, an inner inflatable expansile member, and an outer inflatable expansile member;
- inflating the inner inflatable expansile member to at least partially center a distal end of the clot capture catheter within the vessel; and
- inflating the outer inflatable expansile member to provide atraumatic occlusion and flow arrest of the vessel.
20. The clot capture procedure of claim 19, wherein the inflating the inner inflatable expansile member is performed independently of inflating the outer inflatable expansile member.
Type: Application
Filed: Jul 21, 2022
Publication Date: Jan 19, 2023
Applicant: Neuravi Limited (Galway)
Inventors: David VALE (Barna), Brendan CASEY (Galway), Brian FAHY (Galway), Kevin McARDLE (Loughrea), Eamon BRADY (Loughrea), Jill AMSTUTZ (Menlo Park, CA), Maeve HOLIAN (Galway), Daniel KING (Galway), Michael GILVARRY (Headford)
Application Number: 17/870,298