Catheter funnel extension

Abstract

To provide a system for retrieving an obstruction in a blood vessel.SOLUTION: The present disclosure includes a system for retrieving a blood clot in a blood vessel using a clot retrieval device having an expansile funnel that can engage with the blood clot. The present disclosure also includes a clot retrieval device having an expandable framework that can engage with the blood clot. The expansile funnel and the expandable framework can expand from a collapsed delivery state into an expanded deployed state, increasing cross-sectional area of the clot retrieval device engaging with the blood clot. The increased cross-sectional area of the clot retrieval device can increase suction force, providing effective removal of the clot from a patient.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] Broadly speaking, the present invention relates to a system and method for removing acute occlusions from blood vessels during endovascular treatment.

Background Art

[0002] Thrombectomy catheters and devices are often used for mechanical thrombus removal in endovascular interventions when patients suffer from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Since blood clots that form within blood vessels must be removed as soon as possible to prevent long-term disability, brain damage, or death, the time immediately following these life-threatening events is critical. In the prior art, access to the neurovascular bed can be difficult because the target blood vessels are small in diameter, remote from the insertion site, and highly tortuous. Conventional devices are often either too large in profile, lacking the deliverability and flexibility required to navigate tortuous blood vessels, or completely ineffective at removing blood clots when delivered to the target site. Furthermore, tissue plasminogen activator ("tPA") has been the conventional FDA-approved treatment for removing blood clots within the brain. However, the effectiveness of tPA can be reduced when the blood clot is within the main blood vessel. This shortcoming has prompted the need for a device that can effectively and rapidly remove blood clots within the main blood vessel.

[0003] The presence of blood clots can further complicate the procedure by assuming a number of complex forms and consistencies, ranging from a simple tubular structure that conforms to the shape of the blood vessel to long, strand-like configurations that can span multiple blood vessels at once. The age of a clot can also affect its extensibility, with older clots tending to be less compressible than fresher ones. Empirically, it has also been demonstrated that the mechanical properties of a clot can be affected in significant ways depending on the nature of its interaction with a clot retrieval device. Additionally, several mechanisms can serve to strongly adhere the clot to the vessel wall. Disrupting these attachments without damaging delicate neurovascular vessels can pose a significant challenge.

[0004] Effective delivery of devices to the small, highly branched cerebral arterial system remains difficult, and conventional clot retrieval devices can suffer from a number of drawbacks. The retrieval device must have axial stiffness to provide smooth advancement along the path, while also being flexible enough to navigate the vasculature and withstand high strains. Once at the target site, retrieval of the object from the body is more difficult because typical objects retrieved from the body are substantially larger in dimension than the device, so retrieval of the object into the distal tip is more challenging. For example, a firm, fibrin-rich clot can clog the distal tip and the device of a conventional fixed-port catheter, making it often difficult to extract. Additionally, this clogging can shear soft portions of the clot from the firm regions.

[0005] A narrow diameter and fixed tip size are also inefficient in inducing the suction necessary for removal of blood and thrombotic material during the procedure. The suction must be strong enough so that any debris that may result from the use of aspiration or mechanical thrombectomy devices is kept stationary so that it does not migrate distally and occlude the blood vessel. However, when aspirating with a fixed-port catheter or device, a significant portion of the aspiration flow will come from the vascular fluid proximal to the tip of the catheter or device where there is no clot. This can significantly reduce the aspiration efficiency and decrease the success rate of clot removal. SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

[0006] Accordingly, the applicants recognize the need for an improved method, apparatus, and system that incorporates an expandable funnel that deploys outside the catheter and enables effective and rapid retrieval of blood clots by a higher thrombus removal force obtained from an increased thrombus engagement area. In addition, there is a need for an improved method, apparatus, and system that incorporates a stent retriever having an expandable framework that functions as a funnel catheter tip extension to provide effective and rapid retrieval of blood clots.

Means for Solving the Problems

[0007] Broadly speaking, a system is provided for retrieving an intravascular blood clot using a blood clot retrieval device having an expandable funnel capable of engaging the blood clot. The present disclosure also includes a blood clot retrieval device having an expandable framework capable of engaging the blood clot. The expandable funnel and the expandable framework can expand from a folded delivery state to an expanded deployed state to increase the cross-sectional area of the blood clot retrieval device that engages the blood clot. The increase in the cross-sectional area of the blood clot retrieval device can increase the aspiration suction force and enable effective removal of the blood clot from the patient.

[0008] Exemplary systems for retrieving occlusions in blood vessels can include an outer catheter that facilitates introducing any one of a microcatheter, a guide wire, or many commercially available products to a target site within the vasculature. The outer catheter can be one or both of a guide catheter and an intermediate catheter. The blood clot retrieval device may be within the outer catheter. The blood clot retrieval device can include an elongate flexible delivery wire having a distal end, an expandable tube having a lumen and fixed to the distal end of the elongate flexible wire, and an expandable funnel fixed to the expandable tube. The expandable funnel can be expandable from a folded delivery state in which the expandable funnel can have a circumference substantially the size of the lumen of the outer catheter to an expanded deployed state in which the expandable funnel can have a circumference larger than the circumference of the lumen of the outer catheter. The expandable funnel can comprise a fluid-impermeable flexible tube, an open distal port at the distal end of the flexible tube, and first and second rings of struts fixed to and structurally supported by the flexible tube. The fluid-impermeable flexible tube can comprise a lumen in fluid communication with the lumen of the expandable funnel. The second ring of struts can be disposed proximal to the first ring of struts. An air intake source can be attached to the system to apply suction through the fluid passageways of the outer catheter and the blood clot retrieval device.

[0009] When the expandable funnel is in the expanded deployed state, approximately half of the blood clot retrieval device can be disposed within the lumen of the outer catheter, while approximately half of the blood clot retrieval device can be disposed within the blood vessel.

[0010] When the expandable funnel is in the expanded deployed state and the expandable tube is disposed within the lumen of the outer catheter, the outer wall of the expandable tube can form a seal against the lumen of the outer catheter.

[0011] When the expandable funnel is in the expanded deployed state, the expandable funnel can expand to be circumferentially juxtaposed with the lumen of the blood vessel.

[0012] When the expandable funnel is in the folded delivery state, a portion of the expandable funnel and the expandable tube can have a common circumferential dimension.

[0013] When the expandable funnel is in the folded delivery state and is disposed within the lumen of the outer catheter, the lumen of the flexible tube, the lumen of the expandable tube, and the lumen of the outer catheter can be coaxially aligned about the longitudinal axis.

[0014] The fluid-impermeable flexible tube can provide the only structural support for the expandable funnel between the first ring and the second ring of the struts. The fluid-impermeable flexible tube can be sutured and / or adhered to the first ring of the struts and the second ring of the struts. The fluid-impermeable flexible tube can include a flexible polymeric material.

[0015] Another exemplary system can include an outer catheter that facilitates introducing a microcatheter, a guidewire, or any of a number of commercially available products to a target site within a vascular structure. The outer catheter can be one or both of a guide catheter and an intermediate catheter. The stent retriever may be within the lumen of the outer catheter. The stent retriever can include an elongate flexible delivery wire, an expandable framework, and a fluid-impermeable membrane. The expandable framework can engage and capture an occlusion within a blood vessel by expanding from a folded delivery configuration to an expanded deployment configuration. The proximal end of the expandable framework can be attached to the distal end of the delivery wire. The expandable framework can include a tubular portion that can have an elongate tubular shape when expanded. The expandable framework can taper proximally from the tubular portion to the distal end of the delivery wire. The fluid-impermeable membrane can be secured to the expandable framework near the proximal end of the framework such that the fluid-impermeable membrane has a funnel shape when the expandable framework is in the expanded configuration.

[0016] The tubular portion of the expandable framework can have a plurality of cell openings sized to pass an occlusion when the expandable framework expands from its folded delivery configuration.

[0017] The system can comprise an expandable framework including a closed distal end portion that extends distally away from the tubular portion of the framework and radially inwardly toward a central axis.

[0018] The tubular portion can be expandable to have a circumference substantially the same as the circumference of a blood vessel when the expandable framework is in its expanded deployment configuration, enabling complete engagement with an occlusion.

[0019] The system can include a microcatheter sized to traverse the lumen of an outer catheter. The expandable framework can be sized to traverse the lumen of the microcatheter when in its folded delivery state.

[0020] When deployed a blood vessel as part of a treatment, the fluid-impermeable membrane can have a first outer circumference substantially equal to the inner circumference of the lumen of the outer catheter and a second outer circumference substantially equal to the inner circumference of the blood vessel. When the expandable framework is in its expanded configuration, a portion of the proximal portion of the expanded framework can be disposed within the lumen of the outer catheter. This configuration can provide an external force on the lumen of the outer catheter such that a fluid-impermeable seal is formed between the fluid-impermeable membrane and the lumen of the outer catheter. This configuration can further provide a force between the fluid-impermeable membrane and the wall of the blood vessel such that a fluid-impermeable seal is formed between the fluid-impermeable membrane and the wall of the blood vessel.

[0021] Exemplary methods for retrieving an occlusion from a blood vessel can include one or more of the following steps presented in any order. Exemplary methods can include additional steps recognized and understood by those skilled in the art. Exemplary methods can be performed by the exemplary systems disclosed herein, variations thereof, or alternatives thereto, as recognized and understood by those skilled in the art.

[0022] The method can include accessing a patient's arterial blood vessel using an outer catheter, positioning the distal end of the outer catheter in proximity to the occlusion, advancing a microcatheter and an expandable framework having a fluid-impermeable membrane through the lumen of the outer catheter in a collapsed delivery state, crossing the occlusion with the microcatheter and the expandable framework in a collapsed configuration, retracting the microcatheter within the lumen of the outer catheter while the expandable framework maintains contact with the occlusion, expanding a portion of the expandable framework over the entire occlusion, expanding the distal and proximal portions of the membrane to circumferentially juxtapose with the lumen of the outer catheter, and aspirating through a fluid passageway.

[0023] The method can include advancing the outer catheter to a distance of about 3 millimeters away from the occlusion.

[0024] The method can include removing the expandable framework containing the occlusion from the patient by retracting a portion of the expandable framework within the lumen of the outer catheter during aspiration.

[0025] The method can include injecting a contrast agent within the lumen of the outer catheter to evaluate the extent of the occlusion remaining within the blood vessel. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and further aspects of the present invention will be further considered with reference to the following description in conjunction with the accompanying drawings, in which like numerals in the various drawings indicate like structural elements and features. The drawings are not necessarily to scale, and instead, emphasis is placed on illustrating the principles of the present invention. The figures depict one or more implementations of the apparatus of the present invention by way of example and not limitation. Those skilled in the art are expected to be able to envision and combine elements from the multiple figures in a manner that better suits the user's desires.

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Mode for Carrying Out the Invention

[0027] Here, specific embodiments of the present invention will be described in detail with reference to the drawings, where the same reference numerals indicate functionally similar or identical elements.

[0028] An important factor for success in endovascular treatment such as aneurysm treatment is related to the obstruction removal force defined as the product of the vacuum pressure and the catheter cross-sectional area. In some treatments, mechanical clot removal devices, generally referred to herein as "stent retrievers," are also used in combination with aspiration. To increase the obstruction removal force, either the vacuum pressure or the catheter cross-sectional area may be increased. The disclosed technology relates to a clot retrieval device that includes an expandable funnel that can increase the cross-sectional area of the device that can contact the obstruction. Alternatively, the technology of the present disclosure relates to a stent retriever that includes an expandable framework with a membrane thereon that can provide an opening sealed to the catheter lumen, the sealed opening providing a cross-sectional area in contact with the obstruction that is larger than the cross-sectional area of the catheter. The obstruction removal force can be increased due to the increased cross-sectional area, resulting in improved removal of the obstruction from the patient compared to aspiration through the catheter alone.

[0029] Accessing various blood vessels within the vasculature, regardless of whether they are coronary, pulmonary, or cerebral vessels, involves well-known procedural steps and the use of numerous conventional commercially available accessory products. These products, such as angiographic materials, rotary hemostatic valves, and guidewires, are widely used in laboratories and medical procedures. When these products are used in conjunction with the systems and methods of the present invention in the following description, their functions and exact configurations are not described in detail.

[0030] FIG. 1A shows a system 10 for retrieving an occlusion (T). FIG. 1B shows a cross-section of the system 10 shown in FIG. 1A. Referring collectively to FIGS. 1A and 1B, the exemplary system 10 includes a blood clot retrieval device 100 and an outer catheter 200. The blood clot retrieval device 100 is slidably translatable within the lumen 202 of the outer catheter 200 and is expandable such that when the distal funnel 106 portion slides distally and exits the outer catheter 200, the distal funnel 106 portion of the device 100 expands to the wall of the blood vessel (BV) and the proximal portion 104 of the device expands to the wall of the lumen 202 of the outer catheter 202. The system 10 can be configured to aspirate through the catheter 200 and the expanded device 100 to remove and / or extract an occlusion (T) including an occlusive blood clot or thrombus, debris, and / or other foreign matter within the patient's blood vessel (BV).

[0031] Figure 2 shows an end perspective view of a system 10a that includes a blood clot retrieval device 100a and an outer catheter 200. The device 100a shown in Figure 2 can be configured to function in accordance with the principles of the device 100 shown in Figures 1A and 1B. The system 10a shown in Figure 2 can be configured to be disposed within a blood vessel (BV) to retrieve an occlusion (T), similar to the system 10 shown in Figure 1A. The distal funnel portion 106 of the device 100a shown in Figure 2 includes a fluid-impermeable flexible tube 110a secured to a strut framework 116a. The strut framework 116a includes a first distal ring 112 of struts and a second ring 114 of struts disposed in a proximal direction (PD) relative to the first ring 112 of struts. The first and second rings 112, 114 of struts can be disposed in proximity to the open distal mouth 108 of the expandable funnel 106. In some embodiments, the device 100a can include one or more additional rings of struts disposed in a proximal direction (PD) relative to the first and second rings 112, 114 of struts. In some embodiments, the strut framework 116a can extend within the lumen 105 of the expandable tube 104. In some embodiments, the first and second rings 112, 114 of struts are separated such that the flexible tube 110a structurally supports each ring 112, 114 of struts. The distal end of the fluid-impermeable flexible tube 110a can define the open distal mouth 108 of the device 100a. In some embodiments, the cover 110a can be a fluid-impermeable flexible tube secured to the strut framework 116a. The fluid-impermeable flexible tube 110a can be sutured to the strut framework 116a as shown in Figure 2.

[0032] FIG. 3 shows a side view of a system 10b including a blood clot retrieval device 100b and an outer catheter 200. The device 100b shown in FIG. 3 can be configured to function according to the principles of the device 100 shown in FIGS. 1A and 1B. The system 10b shown in FIG. 3 can be configured to be disposed within a blood vessel (BV) to retrieve an occlusion (T), similar to the system 10 shown in FIG. 1A. The expandable tube 104 and distal funnel 106 of the device 100b shown in FIG. 3 can include a strut framework 116b and a fluid-impermeable tube, coating, or membrane 110b. In contrast to the framework 116a shown in FIG. 2, the framework 116b shown in FIG. 3 can be continuous. The framework 116b shown in FIG. 3 may be formed to structurally support a fluid-impermeable cover 110b, may be manufactured from a suitable material, and may be constructed in other ways. In some embodiments, the cover 110b can include a fluid-impermeable flexible tube, and the tube 110b can be adhered to the strut framework 116b. The fluid-impermeable flexible 110 can be adhered to the strut framework 116a by applying heat.

[0033] Referring collectively to FIGS. 1A, 1B, 2, and 3, the outer catheter 200 can be sized, constructed, and otherwise configured to navigate a blood vessel (BV) to a treatment site and facilitate introduction of the clot retrieval devices 100, 100a, 100b across an occlusion (T). In one embodiment, the outer catheter 200 can be an aspiration catheter. The aspiration catheter can be of the rapid exchange (RX) type. The outer catheter 200 can include a lumen 202 that traverses the length of the outer catheter 200. The lumen 202 can be sized to receive the clot retrieval devices 100, 100a, 100b and provide sufficient space for the clot retrieval device 100 to move longitudinally along the longitudinal axis through the lumen 202 when the system 10 approaches and engages the occlusion (T). The systems 10, 10a, 10b can include an aspiration source (AS) configured to apply suction through a fluid passageway within the lumen 202 of the outer catheter 204. The aspiration source (AS) can provide sufficient suction to engage the clot retrieval devices 100, 100a, 100b with the occlusion (T) and effectively remove the occlusion (T) from the patient's blood vessel (BV). In one embodiment, the aspiration source (AS) can first be applied to the lumen 202 of the outer catheter 200 and subsequently directed to the expandable funnel 106 of the clot retrieval devices 100, 100a, 100b.

[0034] The clot retrieval devices 100, 100a, 100b can include a flexible delivery member 102 (also generally referred to herein as a “delivery wire”), an expandable tube 104, and an expandable funnel 106. The expandable tube 104 can be affixed to the distal end of the delivery wire 102, and the expandable funnel 106 can extend distally from the expandable tube 104. The clot retrieval device 100 including the delivery wire 102, the expandable tube 104, and the expandable funnel 106 can be sized to fit within the lumen 202 of the outer catheter 200. The devices 100, 100a, 100b may or may not include a defined transition between the expandable tube 104 and the expandable funnel 106.

[0035] While delivering systems 10, 10a, 10b through the vascular structure, when the catheter 200 is advanced through the vascular structure, the devices 100, 100a, 100b can be completely retained within the lumen 202 of the outer catheter 200. When the distal end of the catheter 200 is positioned near the occlusion (T), the delivery wire 102 can be pushed distally to move the expandable funnel 106 distally out of the lumen 202 of the catheter 200. The expandable funnel 106 can be expandable to be circumferentially juxtaposed with the wall of the blood vessel proximal to the occlusion (T) while the expandable tube 104 remains disposed within the lumen 202 of the catheter 200. The distal opening 108 of the expandable funnel 106 can have a circumference 210 that is substantially equal to the inner circumference 212 of the blood vessel (BV) when expanded within the blood vessel (BV). Thus, the expandable funnel 106 can be expandable to an expanded deployed state having an outer circumference 210 that is larger than the circumference 208 of the lumen 202 of the outer catheter 200. The expandable funnel 106 can provide a fluid passage to the lumen 105 of the expandable tube 104. The lumen 105 of the expandable tube 104 can be in fluid communication with the lumen 202 of the catheter 200 such that when a suction source (AS) is applied, the suction force can reach the occlusion (T) sufficiently. The expandable tube 104 can expand to have an outer circumference that is substantially equal to the circumference 208 of the lumen 202 of the outer catheter 200.

[0036] The expandable tube 104 can be disposed proximate to the distal end of the delivery wire 102. The expandable tube 104 can be secured to a plurality of connection struts 120 disposed on the distal end of the delivery wire 102. The expandable tube 104 can expand and retract to accommodate delivery catheters having different diameters.

[0037] Referring collectively to FIGS. 1A, 1B, 2, and 3, the delivery wire 102 may be coated with a hydrophilic and / or hydrophobic lubricious polymer including polyvinylpyrrolidone, polytetrafluoroethylene, or silicone to reduce friction between the components of systems 10, 10a, 10b and between the components of systems 10, 10a, 10b and the blood vessel (BV). The delivery wire 102 may have not only sufficient flexibility for a physician to manipulate the clot retrieval devices 100, 100a, 100b through the blood vessel (BV), but also sufficient rigidity to effectively guide the clot retrieval devices 100, 100a, 100b to the target site. In one embodiment, the delivery wire 102 may be solid steel. In another embodiment, the delivery wire 102 may be a nitinol core wire. In one embodiment, the distal end 103 of the delivery wire 102 can include a plurality of connection struts 120. The connection struts 120 may be provided with the same material as the delivery wire 102. The connection struts 120 can connect the distal end 103 of the delivery wire 102 to the expandable tube 104, as shown in FIG. 1B.

[0038] The expandable funnel 106 can be secured to the distal end of the expandable tube 104. The expandable funnel 106 can be expanded from a folded delivery state to an expanded deployed state. In the folded delivery state, the expandable funnel 106 is dimensioned to traverse the lumen 202 of the outer catheter 200. In this configuration, the expandable funnel 106 can be folded back or folded upon itself to fit properly within the lumen 202 of the outer catheter 200. The expandable funnel 106 can be folded back or folded radially inwardly toward the longitudinal axis. In the folded delivery state, at least a portion of the expandable funnel 106 and the expandable tube 104 can have a common circumference. In the folded delivery state, the lumen 111 of the fluid-impermeable flexible tube 110, the lumen 105 of the expandable tube 104, and the lumen 202 of the outer catheter 200 can be coaxially aligned about the longitudinal axis (LA). In this configuration, the blood clot retrieval device 100 can be transported through the body using catheters of various diameters until the blood clot retrieval device 100 is proximate to the occlusion (T) within the blood vessel (BV).

[0039] The expandable funnel 106 can assume an expanded configuration by self-extending radially outward from the longitudinal axis when exiting the distal end of the outer catheter 200. In one embodiment where the expandable funnel 106 can be folded back or compressed when in the folded delivery state, when the expandable funnel 106 exits the outer catheter 200, the expandable funnel 106 can provide a spring-like force that promotes the self-expansion of the expandable funnel 106. When in the expanded deployed state, the expandable funnel 106 can expand such that it has an outer perimeter 210 that is larger than the circumference 208 of the lumen 202 of the outer catheter 200. In one embodiment, the expandable funnel 106 in the expanded deployed state can have a circumference 210 that is approximately equal to the circumference 212 inside the blood vessel (BV). Thus, when suction is applied, the expandable funnel 106 seals with the blood vessel (BV) or can create sufficient restriction such that blood and blood clots distal to the distal opening 108 of the expandable funnel 106, rather than the blood proximal to the expandable funnel 106, are drawn into the blood clot retrieval devices 100, 100a, 100b. In the expanded deployed state, at least a portion of the blood clot retrieval device 100 can be disposed within the lumen 202 of the outer catheter 200. In one embodiment, in the expanded deployed state, approximately half of the blood clot retrieval devices 100, 100a, 100b can be disposed within the lumen 202 of the outer catheter 200. The blood clot retrieval devices 100, 100a, 100b can be coaxially disposed along the longitudinal axis (LA) within the lumen 202 of the outer catheter 202. In the expanded deployed state, at least a portion of the blood clot retrieval devices 100, 100a, 100b can be disposed within the lumen of the blood vessel (BV). In one embodiment, in the expanded deployed state, approximately half of the blood clot retrieval devices 100, 100a, 100b can be disposed within the lumen of the blood vessel (BV).

[0040] The expandable funnel 106 may include a distal port 108. In the expanded deployed state, the distal port 108 may be open and configured to engage an occlusion (T). The open distal port 108 may have a circumference that is approximately equal to the circumference 212 of the blood vessel (BV). The distal port 108 may have a circumference that is approximately equal to or greater than the circumference of the occlusion (T). Since the open distal port 108 has a circumference that is approximately equal to or greater than the circumference of the occlusion, the distal port 108 of the expandable funnel 106 can engage and receive the occlusion (T). When an air intake source is connected and suction is initiated, the occlusion expandable funnel 106 can further receive the occlusion (T), such that the occlusion (T) can be drawn into the expandable funnel 106 and specifically into the lumen 111 of the fluid-impermeable flexible tube 110. The expandable funnel 106 can be gradually compressed to a smaller diameter during the recovery of the occlusion (T) so as to be fully received within the expandable tube 104 of the blood clot recovery devices 100, 100a, 100b. Subsequently, the occlusion (T) can be safely and effectively removed from the patient. When the occlusion (T) clogs within the distal port 108, suction is maintained and the open port 108 protects the occlusion (T) and prevents its removal as the blood clot recovery devices 100, 100a, 100b are retracted within the sheath or outer catheter 200.

[0041] The large distal ports 108 of the clot retrieval devices 100, 100a, 100b of the systems 10, 10a, 10b illustrated in this specification can provide improved performance over conventional fixed port designs. Conventional fixed port catheters can be obstructed by a hard fibrin-rich clot clogging the catheter tip or by the soft portion of the clot being sheared. When aspirating through a fixed port catheter, a significant portion of the suction is directed to the fluid proximal to the tip, which may reduce the suction induced in the clot and the success rate of clot removal. If the diameter of the expandable distal port 108 can be of the same order as the diameter of the blood vessel, shearing of the clot at the catheter port can be reduced and the volume of fluid and clot distal to the port can be protected. However, the expandable funnel 106 of the technology of the present disclosure can increase the amount of suction force by increasing the cross-sectional area of the engagement between the expandable funnel and the occluder, and as a result, can more effectively remove the occluder (T).

[0042] FIG. 1B is a cross-sectional view of the interior of the expandable tube 104 when the clot retrieval device 100 is in an expanded deployed state. As shown in FIG. 1B, the delivery wire 102 can include a connection strut 120. The connection strut 120 can be fixed to the wall of the expandable tube 104. A fluid-impermeable flexible tube, membrane, coating, or other cover 110 can cover at least a portion of the outer wall of the expandable tube 104. A seal 118 can be formed against the inner wall of the outer catheter 200 when the outer wall of the expandable tube 104 exerts a force on the inner wall of the outer catheter 200. The seal 118 can direct the suction source to the occluder (T) to ensure that the clot retrieval device 100 can capture the occluder (T). The cover 110 can be fixed or integrated with the expandable tube 104 and can be configured to expand in other ways to form a seal between the outer surface of the membrane 110 and the inner wall of the lumen 202 of the outer catheter 200. The lumen 105 of the expandable tube 104 can be in fluid communication with the lumen 202 of the catheter 200 such that when a suction source (AS) is applied, the suction force can reach the occluder (T) sufficiently with minimal or no flow between the membrane or cover 110 and the inner wall of the lumen 202.

[0043] The clot capture devices 100a, 100b illustrated in FIGS. 2 and 3 can similarly include a cover 110 on the proximal portion 104 of the devices 100a, 100b. The outer flexible tube 110a shown in FIG. 2 can extend to cover the proximal portion of the device 100a to form the cover 110 shown in FIG. 1B. The fluid-impermeable flexible tube 110a of the device 100a shown in FIG. 2 can include a lumen 111. The lumen 105 of the proximal expansion tube 104 can be in fluid communication with the lumen 111 of the fluid-impermeable flexible tube 110a such that when an intake source (AS) is applied, the intake force can reach the occlusion (T) sufficiently. Alternatively, the proximal expansion tube 104 of the device 100a shown in FIG. 2 can include a separate cover, coating, membrane, or seal to direct the intake through the funnel 106 and the lumen 202 of the catheter.

[0044] Similarly, the cover 110b (fluid-impermeable flexible tube, membrane, coating, or other cover) of the device 100b shown in FIG. 3 can extend to cover the funnel 104 and the tube 104 portion of the device 100b, or the funnel 106 and the tube 104 can be unevenly covered. The cover 110b can extend into the expansion tube 104. The cover 110b can cover at least a portion of the inner wall of the expansion tube 104.

[0045] Referring collectively to FIGS. 1A, 1B, 2, and 3, the devices 100, 100a, 100b may include a distal end 122. The distal end 122 may correspond to the distal ends of the covers 110, 110a, 110b of the funnels 106 of the devices 100, 100a, 100b. In embodiments where the covers 110, 110a, 110b extend to the proximal expandable tubes 104 of the devices 100, 100a, 100b, when the blood clot retrieval devices 100, 100a, 100b are in an expanded deployed state, the distal ends 122 of the covers 110, 110a, 110b may have a circumference 210 that is larger than the circumference of the proximal ends of the covers 110, 110a, 110b. The distal end 122 can have a circumference at least of the dimensions of the circumference of the occlusion (T), and when an air intake source (AS) is applied, enables the expandable funnel 106 including the covers 110, 110a, 110b to receive the occlusion (T). The covers 110, 110a, 110b can include a flexible polymeric material. For example, the covers 110, 110a, 110b may be formed from a ductile elastomer. Ductile elastomers have the advantage of being soft and flexible and have tear resistance and puncture resistance due to high fracture strain. In one embodiment, the covers 110, 110a, 110b may include urethane or other similar materials. The covers 110, 110a, 110b can provide the blood clot retrieval devices 100, 100a, 100b with advantageous properties such as high tensile strength, resistance to disintegration, biocompatibility, and flexibility. The fluid-impermeable flexible tube 110 can also be configured to minimize friction between the covers 110, 110a, 110b and the blood vessel (BV) and reduce distortion of the blood vessel (BV). The flexible nature of the covers 110, 110a, 110b can enable the covers 110, 110a, 110b to stretch when the expandable funnel 106 expands from a folded delivery state to an expanded deployed state. When the covers 110, 110a, 110b stretch, the covers 110, 110a, 110b can follow the contour of the underlying strut framework 116.In some embodiments, such as those shown in FIG. 2, the cover 110a can include a flexible tube that structurally supports the strut framework 116a and can maintain the relative positions of the first and second rings 112, 114 of the strut. The cover 110a can further include a structure with sufficient structural integrity such that the strut framework 116a can be stitched to the cover 110a. Thus, the funnel 106 portion of the device 100a can further include stitches or other seams for securing the cover 110a to the framework 116a, as shown in FIG. 2.

[0046] The strut frameworks 116a, 116b can have various configurations not shown in FIGS. 1A, 1B, 2, or 3. The configuration of the strut frameworks 116a, 116b can be such that the outer shape of the expandable funnel 106 in the expanded deployed state can hinge radially outward so that the portion juxtaposed with the circumference 212 of the blood vessel (BV) is present. The strut frameworks 116a, 116b can include a plurality of closed cells, loops, or undulations. In one embodiment, the strut frameworks 116a, 116b can include a plurality of distal crowns. In one embodiment, the strut frameworks 116a, 116b can have petal-shaped cells with rounded edges. The petal-shaped cells can open in the expanded deployed state and take on a maximum radial dimension.

[0047] In one embodiment, the covers 110, 110a, 110b can include a fluid-impermeable flexible tube that provides the only structural support for the expandable funnel 106. As shown in FIG. 2, the fluid-impermeable flexible tube 110a can provide the only structural support for the expandable funnel 106 in the region between the first ring 112 of the strut and the second ring 114 of the strut. As shown in FIG. 3, the strut framework 116 can provide support for the expandable funnel 106.

[0048] The ideal diameter of the blood clot retrieval devices 100, 100a, 100b depends on the location of the target occlusion and the diameter of the outer catheter 200 through which the blood clot retrieval devices 100, 100a, 100b can be delivered. To retrieve a blood clot within the cerebrovascular bed where the blood vessel diameter is generally about 3 mm to 6 mm, a suitable system would have an outer catheter 200 with an inner diameter of about 0.070 inches (1.8 mm) and a blood clot retrieval device 100 with an inner diameter of about 0.062 inches (1.6 mm). When deployed from the outer catheter 200, the maximum diameter of the expandable funnel 106 can be at least 3 mm (but in some cases, about 5 - 6 mm), which enables sealing against the wall of the blood vessel (BV) and provides an opening at the distal port that is the same size as the blood vessel (BV) itself.

[0049] Figures 4 - 6 include diagrams of an alternative system 10c for retrieving an occlusion (T) within a blood vessel (BV). The system 10c can comprise a catheter 200 and a funnel-shaped stent retriever 300 including an expandable framework 304 for engaging the occlusion (T), where the framework 304 has a fluid-impermeable membrane, cover, or tube secured to its proximal portion. The occlusion (T) can include an occlusive blood clot within a patient's blood vessel (BV). The occlusion can include debris or other foreign matter or mass within the blood vessel (BV). The outer catheter 200 can include a lumen 202 sized, shaped, and otherwise configured to slidably receive the funnel-shaped stent retriever 300. The catheter 200 can be otherwise dimensioned and configured as exemplified and disclosed elsewhere in this specification. Figure 4 shows the system 10c expanded through the occlusion (T) within the blood vessel (BV). Figure 5 shows the system 10c expanded as shown in Figure 4 and comprising the struts of the illustrated expandable framework 304. Figure 6 shows the funnel-shaped stent retriever 300 expanded without being restricted by the catheter 200 or the blood vessel (BV).

[0050] Collectively referring to FIGS. 4-6, the funnel-shaped stent retriever 300 can be disposed within the lumen 202 of the outer catheter 202 during delivery of the device. The funnel-shaped stent retriever 300 can move along the longitudinal axis when the system 10c approaches and engages the occlusion (T).

[0051] The funnel-shaped stent retriever 300 can include an elongate flexible member 102, generally referred to herein as a "delivery wire". The delivery wire 102 can facilitate positioning the stent retriever 300 in proximity to the occlusion (T). The delivery wire 102 may be coated with a hydrophilic and / or hydrophobic lubricious polymer including polyvinylpyrrolidone, polytetrafluoroethylene, or silicone to reduce friction between components of the system 10c and between components of the system 10c and the blood vessel (BV). The delivery wire 102 can have sufficient flexibility for a physician to manipulate the stent retriever 300 through the blood vessel (BV), as well as sufficient rigidity to effectively guide the stent retriever 300 to the target site. In one embodiment, the delivery wire 102 may be solid steel. In another embodiment, the delivery wire 102 may be a nitinol core wire. In one embodiment, the distal end 103 of the delivery wire 102 can include a plurality of connecting struts 120. The connecting struts 120 can include the same material as the delivery wire 102. The connecting struts 120 can connect the distal end 103 of the delivery wire 102 to the expandable tube 104, as shown in FIGS. 4-6. The delivery wire 102 and the connecting struts can be configured as otherwise illustrated and described herein.

[0052] The stent retriever 300 can include an expandable framework 304 configured to engage and capture an occlusion (T). The framework 304 is exemplified as having a structure similar to that disclosed in U.S. Patent No. 9,445,829, which is incorporated herein by reference as if set forth in its entirety herein. Alternatively, the expanded framework 304 may have a structure similar to that of the framework of other known stent retriever devices, or a modification thereof, as would be understood by one of ordinary skill in the art in accordance with the teachings of the present disclosure. As a non-exhaustive list of frameworks of such stent retriever devices, U.S. Patent Nos. 10,292,723, 8,852,205, 9,301,769, 10,229,881, 10,420,570, 10,201,360, and 10,363,054, and U.S. Patent Application Publication No. 2017 / 0071614 are incorporated herein by reference as if set forth in their entirety herein.

[0053] The expandable framework 304 can be made of a material that can self-expand into an expanded configuration when released from a folded delivery state, such as a shape memory material. Additionally or alternatively, the expandable framework 304 can be made of a superelastic material. In one embodiment, the superlattice alloy can be an alloy with nitinol or similar properties. In one embodiment, the superelastic alloy can include nickel and titanium. The expandable framework 304 can have multiple configurations. The expandable framework 304 can be manufactured by laser cutting a nitinol tube, followed by applying heat and electrolytic polishing to form the desired framework. The expandable framework 304 can include radiopaque markers that can be used to visualize the expandable framework 304 using fluoroscopy.

[0054] When the expandable framework 304 is in an expanded deployment configuration, the expandable framework 304 can have a substantially tubular shape. In the expanded deployment configuration, the expandable framework 304 can include a tubular portion 310, a proximal portion 306, and a distal portion 312. The tubular portion 310 can extend distally from the proximal portion 306. The proximal portion 306 of the expandable framework 304 can be fixed to the distal end 103 of the delivery wire 102. In one embodiment, the proximal portion 306 can be fixed to the distal end 103 of the delivery wire 102 by a color coupler 316, as shown in FIG. 6. The color coupler 316 can include the features and functions of one or more color couplers disclosed in U.S. Patent Application Nos. 16 / 150,024 and 16 / 667,454, which are incorporated herein by reference in their entirety as if fully set forth herein.

[0055] In an alternative embodiment, the proximal portion 306 can be welded to the distal end 103 of the delivery wire 102. When the expandable framework 304 is in an expanded deployment configuration, the proximal portion 306 of the expandable framework 304 can taper such that the proximal portion 306 narrows from the tubular portion 310 to the point where the expandable framework 304 can be fixed to the delivery wire 102. The tapering of the proximal portion 306 can create a funnel-like shape, as shown in FIGS. 4-6. The distal portion 312 can extend distally from the tubular portion 310. When the expandable framework 304 is in an expanded deployment configuration, the distal portion 312 can taper such that the distal portion 312 narrows from the tubular portion to the distal junction 326. The distal portion 312 can be closed with cell openings small enough to prevent clot material from moving distally through the distal portion 312 from inside the framework 304. Alternatively, the funnel stent retriever need not include a tapered or closed distal portion 312; for example, the distal end of the framework 304 can be open.

[0056] Due to the tapering of the distal portion 312, a conical or funnel-shaped configuration can be created as shown in FIGS. 4-6. The distal portion 312 can include a distal coil 328 as shown in FIG. 6. The distal coil 328 and the distal portion 312 can attach at a distal junction 326. The distal junction 326 can be a collar fitting.

[0057] The ideal diameter of the expandable framework can depend on the location of the target occlusion and the diameter of the outer catheter through which the expandable framework 304 is delivered. To retrieve a blood clot in the internal carotid artery where the vessel diameter can be about 3 mm to 6 mm, the applicable system 10c can include an expandable framework 304 of about 3 mm to 6 mm. In one embodiment, the expandable framework 304 can be slightly larger than the diameter of the blood vessel (BV) and can form a seal with the inner wall of the blood vessel. The ideal length of the expandable framework 304 can depend on the location of the target and the characteristics of the occlusion (T). In one embodiment, the length of the expandable framework 304 can be about 30 mm. In another embodiment, the length of the expandable framework can be about 40 mm.

[0058] As shown in FIG. 6, in one embodiment, the expandable framework 304 can include an inner body 318 and an outer body 320. The inner body 318 can be disposed within the outer body 320. The inner body 318 has a substantially longitudinally tubular configuration and can traverse the length of the tubular portion 310 of the expandable framework 304. The inner body 318 and the outer body 320 can be connected to the distal end 103 of the delivery wire 102. The inner body 318 can include a distal portion 324 proximate to the distal portion 312 of the expandable framework 304. The distal portion 324 of the inner body 318 can have a particular wire configuration that facilitates engagement with the occlusion (T) and can prevent fragments of the occlusion from slipping out of the expandable framework 304. The particular wire configuration can have an elliptical shape oriented substantially perpendicular. The particular wire configuration can be secured to the inner body 318, the outer body 320, or both.

[0059] The stent retriever 300 can include a fluid-impermeable membrane 308. The fluid-impermeable membrane 308 can be secured to the proximal portion 306 of the expandable framework 304. The fluid-impermeable membrane 308 can also be secured to the expandable framework 304 that extends within the lumen 202 of the outer catheter 200. The fluid-impermeable membrane 308 can be made of a porous material. The porous material includes pores having dimensions smaller than the dimensions of blood molecules, thereby preventing the blood molecules from passing through the fluid-impermeable membrane 208. Due to the flexible nature of the fluid-impermeable membrane 308, when the expandable framework expands from the folded delivery state to the expanded deployment state, the fluid-impermeable membrane 308 can stretch. When the fluid-impermeable membrane 308 stretches, the membrane 308 can conform to the contour of the underlying expandable framework 304. In one embodiment, the fluid-impermeable membrane 308 can cover at least a portion of the proximal portion 306 of the expandable framework 304. In another embodiment, the fluid-impermeable membrane 308 can cover the entire proximal portion 306 of the expandable framework. The fluid-impermeable membrane 308 can cover the proximal portion 306 of the expandable framework 304 that extends within the lumen 202 of the outer catheter 200. When the fluid-impermeable membrane 308 covers at least a portion of the proximal portion 306 of the expandable framework 304 and the expandable framework 304 extends within the lumen 202 of the outer catheter 200, a funnel-shaped configuration can be created. The fluid-impermeable membrane 308 can include a proximal opening sized to allow intake. In the expanded deployment configuration, the circumference of the proximal opening can be approximately equal to the circumference 208 of the lumen 202 of the outer catheter 200. When an intake force is applied, the proximal opening can allow intake through the funnel-shaped configuration of the fluid-impermeable membrane, facilitating the retrieval of the occlusion (T).

[0060] The expandable framework 304 can have a folded delivery configuration and an expanded deployment configuration. In the folded delivery configuration, the system 10c can include the microcatheter 204. The microcatheter 204 can be dimensioned to traverse the lumen 202 of the outer catheter 200. In the folded delivery configuration, the expandable framework 304 can fold within itself such that the expandable framework 304 can be disposed within the lumen 205 of the microcatheter 204.

[0061] In the folded delivery state, the first outer circumference 212 and the second outer circumference 214 of the fluid-impermeable membrane 308 can be substantially equal. The first circumference 212 and the second circumference 214 can be substantially equal to the circumference 220 of the lumen 205 of the microcatheter 204. In the folded delivery state, the first circumference 212, the second outer circumference 214, the circumference 330 of the tubular portion 310 of the expandable framework 304, and the circumference 220 of the lumen 205 of the microcatheter 204 can be substantially equal.

[0062] In the expanded deployment state, the tubular portion 310 of the expandable framework 304 can expand such that the circumference 330 of the tubular portion 310 is substantially equal to the circumference of the blood vessel (BV). In one embodiment, the funnel-shaped stent retriever 300 can be configured to treat an occlusion (T) having a circumference substantially equal to the circumference of the blood vessel (BV). In another embodiment, the funnel-shaped stent retriever 300 can be configured to treat an occlusion (T) having a circumference smaller than the circumference of the blood vessel (BV). Since the tubular portion 310 can expand such that its circumference can be substantially equal to the circumference of the blood vessel (BV), the expandable framework 304 can fully engage the occlusion (T).

[0063] In the expanded deployed state, the fluid-impermeable membrane can include a first outer periphery 212 and a second outer periphery 214. The first outer periphery 212 can be approximately equal to the circumference 208 of the lumen 202 of the outer catheter 200, as shown in FIG. 5. The second outer periphery 214 can be approximately equal to the inner circumference 212 of the blood vessel (BV), as shown in FIG. 5. The difference between the circumferences 212, 214 of the fluid-impermeable membrane 308 can enable the membrane 308 to have a substantially funnel shape in the expanded deployed configuration.

[0064] When in the expanded deployed state, a portion of the proximal portion 306 of the expandable framework 304 extending within the lumen 202 of the outer catheter 200 can generate an outward force on the inner wall of the outer catheter 200. The outward force can be sufficient to create a fluid-impermeable seal 332 between the fluid-impermeable membrane 308 covering the proximal portion of the expandable framework 304 extending within the lumen 202 of the outer catheter 200 and the lumen 202 of the outer catheter 200, as shown in FIG. 5. The fluid-impermeable seal 332 can facilitate inspiration and, thus, the removal of the occlusion (T) from the blood vessel (BV) when the aspiration is directed at the occlusion (T).

[0065] FIGS. 7A-7D and 8A-8H illustrate a method of removing an occlusion (T) from a blood vessel (BV) using a system 10c that includes a stent retriever 300 having an expandable framework 304. FIGS. 7A-7D are drawings showing the delivery of the stent retriever 300 to a target site and the capture of the occlusion (T) at the target site. FIGS. 8A-8H are drawings of the vasculature near the target site showing the delivery of the stent retriever 300 to the target site, the capture of the occlusion (T), and the removal of the stent retriever 300 from the patient's body. The drawings of FIGS. 8A-8H are based on photographs of a prototype system 10c that retrieves a blood clot (T) within a silicone model of the vasculature near the Circle of Willis.

[0066] Figures 9A and 9B show the significant improvements that the clot retrieval devices 100a, 100b, 300 can provide as compared to other commercially available products. Figure 9A shows data comparing the dimensions and operation of a prototype clot retrieval device constructed similarly to the devices 100a, 100b shown in FIGS. 2 and 3. Figure 9B shows data comparing the dimensions and operation of a prototype clot retrieval device constructed similarly to the device 300 shown in FIGS. 4 - 8H.

[0067] Optimal retrieval of the occlusion (T) from the blood vessel (BV) may depend on the occlusion removal force. The occlusion removal force may be defined as the product of the applied vacuum pressure multiplied by the cross - sectional area of the clot retrieval device that engages the occlusion (T). When the thrombus removal force is high, the occlusion (T) can be firmly held against the clot retrieval device, resulting in effective removal of the occlusion (T). Increasing the applied vacuum pressure can be one way to increase the occlusion removal force. However, the vacuum pressure can only be increased up to a practical limit (e.g., based on design constraints understood by those skilled in the art). Further, increasing the inner diameter, and thus the cross - sectional area of the catheter, can present challenges as larger catheters are more difficult to track and may also increase the likelihood of blood vessel damage.

[0068] Accordingly, the clot retrieval devices 100a, 100b, and 300 disclosed herein are configured to significantly increase the cross - sectional area that engages the occlusion (T) and, thus, increase the occlusion removal force as compared to commercially available products. By way of example, as shown in FIGS. 9A and 9B, the expandable funnels 106 of the clot retrieval devices 100a, 100b, and the funnel - shaped stent retriever 300 can each expand to a distal inner diameter that is approximately equal to the inner diameter of the blood vessel in which the devices 100a, 100b, 300 are deployed. Irrespective of the particular embodiment of the devices 100a, 100b, 300, assuming the blood vessel has an inner diameter of 0.16 inches or about 4 millimeters, the devices can expand to have a distal inner diameter of about 4 millimeters and also have a cross - sectional area of about 0.030 square inches or 2.0×(10 -5)It can have a cross-sectional area of square meters. Regardless of the specific embodiments of devices 100a, 100b, and 300, when a vacuum pressure of about 29 Hg (98,000 pascals) is applied, the occlusion removal force obtained with the expandable funnel can be about 1.2 newtons (about 127 gram-weights). In contrast, a commercially available catheter identified in FIG. 9A having a distal inner diameter of about 0.070 inches or 1.8 millimeters and a cross-sectional area of about 0.003 square inches or 2.0×(10 -6 ) square meters, when subjected to a vacuum pressure of about 98,000 pascals, the occlusion removal force obtained at the catheter tip can be about 0.21 to about 0.26 newtons (about 21 to 27 gram-weights). In this case, the blood clot retrieval devices 100a, 100b, 300 can provide a cross-sectional area at the tip of the blood clot retrieval devices 100a, 100b, 300 that is about 1,000% larger than other commercially available products, resulting in an occlusion removal force that is about 500% higher than other commercially available products.

[0069] FIG. 10 graphically shows the significantly increased occlusion removal force provided by the blood clot retrieval devices 100a, 100b, 300 compared to commercially available products. In the illustrated example, EMBOVAC has the highest thrombus holding force of about 26 gram-weights and the highest tip cross-sectional area of 2.6×(10 -6 ) square meters among the commercially available devices tested. The blood clot retrieval devices 100a, 100b, 300 of the present disclosure have a tip cross-sectional area and holding force more than 4 times (almost 5 times) that of EMBOVAC's tip cross-sectional area and holding force. Further, since the cross-sectional area (and thus the holding force) of the blood clot retrieval devices 100a, 100b, 300 is limited to a vessel diameter of 4 millimeters in this figure, in vessels with a larger diameter, the tip cross-sectional area and holding force can be even larger.

[0070] FIG. 11 is a flow diagram showing a method 400 for delivering a system including a funnel-shaped stent retriever 300 to a target site, capturing an occlusion, and removing the stent retriever 300 from the patient's body. The method may include one or more of the following steps, which are not shown in a specific order. The exemplary method 400 may further include additional steps recognized and understood by those skilled in the art. The exemplary method may be performed by the exemplary devices disclosed herein, variations thereof, or alternatives thereto, as recognized and understood by those skilled in the art.

[0071] The arteries of the brain can be accessed using a long guidewire 216. When the distal tip of the guidewire 216 reaches the target site, the guidewire 216 can function as a guide for a larger catheter to follow for delivery to the target site. The guidewire 216 can be constructed from solid steel, a nitinol core, or other suitable materials. In one embodiment, the vasculature can be accessed using a guide catheter, such as a balloon catheter.

[0072] In step 402, the patient's arterial vasculature can be accessed using a first catheter 206 having a lumen 207, an intake catheter 200 having a lumen 202, and a microcatheter 204 having a lumen 205. As shown in FIGS. 7A and 8A, the first catheter 206 can have the largest diameter of the catheter delivery system. The first catheter 206 can be the first catheter to enter the patient's blood vessel (BV). The intake catheter 200 can be disposed within the lumen 207 of the first catheter 206. The intake catheter 200 can be the second catheter to enter the patient's blood vessel (BV). The microcatheter 204 can be disposed within the lumen 202 of the intake catheter 200. The microcatheter can have the smallest diameter of the delivery catheter system and can be sized to receive the stent retriever 300 within its lumen 205. As shown in FIGS. 7A and 8A, the catheters 206, 200, 204 can be advanced over the guidewire 216 disposed across the occlusion (T).

[0073] In step 404, as shown in FIGS. 7A and 8B, the intake catheter 200 can be advanced through the lumen 207 of the first catheter 206 and toward the proximal end of the occlusion (T) using techniques known in the art. In one embodiment, the outer catheter 200 is advanced through the lumen 207 of the first catheter 206 until the outer catheter 200 is about 3 millimeters away from the occlusion (T).

[0074] In step 406, as shown in FIGS. 7A and 8A, the microcatheter 204 having the foldable expandable framework 304 therein can be advanced through the lumen 202 of the outer catheter 200 and toward the proximal end of the occlusion (T). The expandable framework 304 can include a fluid-impermeable membrane 308 secured to the expandable framework 304 and folded within the lumen 207 of the microcatheter 204 as the microcatheter 204 advances. While advancing the microcatheter 204 toward the occlusion (T), the guidewire 216 and the outer catheter 200 can be manipulated as needed.

[0075] In step 408, as shown in FIGS. 7B and 8C, the microcatheter 204 having the expandable framework 304 folded within the lumen 207 of the microcatheter 204 can cross the occlusion (T). Subsequently, the guidewire 216 can be removed from the system 10c. As shown in FIG. 8D, the expandable framework 304 can be advanced through the microcatheter 204 until the distal end of the expandable framework 304 breaches the distal tip of the microcatheter 204.

[0076] In step 410, as shown in FIGS. 7C, 7D, 8E, and 8F, while most of the expandable framework 304 remains across the entire occlusion (T), the microcatheter 204 may be retracted into the lumen 202 of the outer catheter 200.

[0077] In step 412, as shown in FIGS. 7C, 7D, 8E, and 8F, at least a portion of the expandable framework 304 can be expanded to engage the occlusion (T). When the microcatheter 204 is retracted into the lumen 202 of the outer catheter 200 in step 410, the expandable framework 304 can self-expand. Additionally or alternatively, the expandable framework 304 can exhibit a spring force that acts to facilitate spring-like expansion when the expandable framework 304 is moved out of the lumen 205 of the microcatheter 204 while the expandable framework 304 is within the lumen 205 of the microcatheter 204.

[0078] In step 414, as shown in FIGS. 8E and 8F, the distal portion of the fluid-impermeable membrane 308 can be expanded. In one embodiment, the distal portion of the fluid-impermeable membrane 308 can be expanded to be circumferentially juxtaposed with the blood vessel (BV). In this configuration, the fluid-impermeable membrane 308 is proximate to the inner wall of the blood vessel (BV).

[0079] In step 416, as shown in FIGS. 7D, 8E, and 8F, the proximal portion of the fluid-impermeable membrane 308 can be expanded. In one embodiment, the proximal portion of the fluid-impermeable membrane 308 can be expanded to be circumferentially juxtaposed with the lumen 202 of the outer catheter 200. In this configuration, the fluid-impermeable membrane 308 can form a seal 332 against the inner wall of the outer catheter 200.

[0080] In step 418, an air intake source can be connected to the system 10c. The air intake source can generate a vacuum pressure that can intake air through the fluid passage defined by the fluid-impermeable membrane 308 and the lumen 202 of the intake catheter 200. The suction can be sufficient to engage the stent retriever 300 and the occlusion (T) during removal of the occlusion.

[0081] In step 420, as shown in FIG. 8G, at least a portion of the expandable framework 304 can be retracted into the lumen 202 of the outer catheter 200. The expandable framework 304 can be retracted into the lumen 202 of the outer catheter 200 until the physician can feel a significant tactile force. A significant tactile force can indicate that the occlusion (T) is successfully positioned within the distal end of the outer catheter 200. At this point, the intake source can be substantially restricted or eliminated.

[0082] In step 422, as shown in FIG. 8H, the stent retriever 300 can be removed from the patient along with the captured occlusion (T).

[0083] In one embodiment, a contrast agent can be injected into the lumen 202 of the outer catheter 200 to obtain the extent of the occlusion remaining within the blood vessel (BV). Examples of the contrast agent can include iodine-based contrast agents.

[0084] The present invention is not limited to the described embodiments, in which the configuration and details can vary. The terms "distal" and "proximal" are used throughout the foregoing description and are meant to refer to the position and direction with respect to the physician performing the treatment. Thus, "distal" or "distally" refers to a position away from or a direction away from the physician. Similarly, "proximal" or "proximally" refers to a position close to or a direction toward the physician.

[0085] In the description of the exemplary embodiments, technical terms are used for the sake of clarity. Each term is intended to have its broadest meaning as understood by those skilled in the art and is intended to include all technical equivalents that operate in a similar manner to achieve a similar purpose. It should also be understood that the reference to one or more steps of a method does not exclude the presence of additional method steps or method steps intervening between those explicitly identified. Each step of the method can be performed in an order different from the order described herein without departing from the scope of the disclosed technology. Similarly, the reference to one or more components in an apparatus or system does not exclude the presence of additional components or components intervening between those explicitly identified.

[0086] As used herein, a "patient" or "subject" can be a human or any animal. It should be understood that the animal can be of any of a variety of applicable types including, but not limited to, mammals, veterinary animals, domestic animals, or pet animals. By way of example, the animal can be an experimental animal (e.g., a rat, dog, pig, monkey, etc.) specifically selected to have certain properties similar to humans.

[0087] As used herein, the term "about" or "approximately" with respect to any numerical value or range of numerical values indicates a reasonable dimensional tolerance that allows a component or collection of components to function in accordance with its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values that are ±20% of the recited value. For example, "about 90%" can refer to a range of values from 71% to 99%.

[0088] As used herein, the terms "comprising", "containing", or "including" mean that at least the specified compound, element, particle, or method step is present in a composition, article, or method, but do not exclude the presence of other compounds, materials, particles, or method steps, even if they have the same function as the specified ones.

[0089] It should also be noted that, as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein from one particular value of "about" or "approximately" to another particular value of "about" or "approximately". When expressing such ranges, other exemplary embodiments also include from one particular value to another particular value.

[0090] The descriptions contained herein are examples of embodiments of the invention and are not intended to limit the scope of the invention in any way. Although specific embodiments of the invention are described, various modifications can be made to the apparatus and methods without departing from the scope and spirit of the invention. For example, the embodiments described herein refer to specific components, but the invention can utilize various combinations of components to achieve the described functionality, utilize alternative materials to achieve the described functionality, combine components from various embodiments, combine components from various embodiments with known components, etc. The invention contemplates replacing the component parts illustrated herein with other well-known commercially available products. Modifications recognized by those skilled in the art relevant to the present invention are intended to be included within the scope of the following claims.

[0091] 〔Embodiments〕 (1) A system for retrieving an occlusive object within a blood vessel, comprising an outer catheter having a lumen therethrough, the lumen having a circumference, and A blood clot retrieval device disposed within the lumen of the outer catheter and translatable through the lumen of the outer catheter, an elongate flexible delivery member having a distal end, an expandable tube having a lumen therethrough, the expandable tube being fixed to the distal end of the elongate flexible delivery wire, an expandable funnel fixed to the expandable tube, the expandable funnel being dimensioned to expand from a folded delivery state in which the expandable funnel traverses the lumen of the outer catheter to an expanded deployed state having an outer circumference greater than the circumference of the lumen of the outer catheter, the expandable funnel comprising: a fluid-impermeable flexible tube having a lumen therethrough, the lumen of the flexible tube communicating with the lumen of the expandable tube, an open distal port disposed at the distal end of the flexible tube, a first ring of struts disposed proximate to the open distal port, the first ring of struts being fixed to and structurally supported by the flexible tube, a second ring of struts disposed proximal to the first ring of struts, the second ring of struts being fixed to and structurally supported by the flexible tube, and an expandable funnel comprising: a blood clot retrieval device, an air intake source configured to apply suction through the lumen of the catheter, the lumen of the sealing tube, and the open distal port, A system comprising. (2) The system according to Embodiment 1, wherein between the first ring of struts and the second ring of struts, the flexible tube is configured to provide the only structural support for the expandable funnel. (3) The system according to Embodiment 1, wherein when the expandable funnel is in the expanded deployed state, substantially half of the clot retrieval device is coaxially disposed along the longitudinal axis within the lumen of the outer catheter. (4) The system according to Embodiment 1, wherein when the expandable funnel is in the expanded deployed state, the expandable tube is disposed within the outer catheter and forms a seal with respect to the lumen of the outer catheter. (5) The system according to Embodiment 1, wherein when the expandable funnel is in the folded delivery state, at least a portion of the expandable funnel and the expandable tube have a common circumferential dimension.

[0092] (6) The system according to Embodiment 1, wherein when the expandable funnel is in the expanded deployed state, the expandable funnel is expandable to be circumferentially juxtaposed with the lumen of the blood vessel. (7) The system according to Embodiment 1, wherein the fluid-impermeable flexible tube is sutured and / or adhered to the first ring of the strut and the second ring of the strut. (8) The system according to Embodiment 1, wherein the flexible tube comprises a flexible polymer material. (9) The system according to Embodiment 1, wherein when the expandable funnel is in the folded delivery state and is disposed within the lumen of the outer catheter, the lumen of the flexible tube, the lumen of the expandable tube, and the lumen of the outer catheter are coaxial about the longitudinal axis. (10) A system for retrieving an occlusion within a blood vessel, an outer catheter having a lumen therethrough, a clot retrieval device disposed within the outer catheter and translatable through the lumen of the outer catheter, an elongate flexible member having a distal end, An expandable framework configured to engage the occluder and expandable from a folded delivery configuration to an expanded configuration, the expandable framework comprising a proximal portion fixed to the distal end of the elongate flexible member and a tubular portion extending distally from the proximal portion, the tubular portion having an elongate tubular shape when the expandable framework is in the expanded configuration, and the proximal portion being tapered proximally from the tubular portion to the distal end of the flexible member when the expandable framework is in the expanded configuration. A fluid-impermeable membrane fixed to the proximal portion of the expandable framework, the fluid-impermeable membrane including a funnel shape when the expandable framework is in the expanded configuration. A blood clot retrieval device comprising: A system comprising:

[0093] (11) The system of embodiment 10, wherein most of the tubular portion of the expandable framework comprises cell openings sized to pass the occluder when the expandable framework expands from the folded delivery configuration to the expanded configuration. (12) The system of embodiment 10, wherein the expandable framework further comprises a closed distal end portion extending distally from the tubular portion and radially inwardly towards the central axis of the tubular portion. (13) Further comprising a microcatheter sized to transverse the lumen of the outer catheter. (16) The system of embodiment 10, wherein the expandable framework is sized to transverse the lumen of the microcatheter when the expandable framework is in the folded delivery configuration. (14) The system of embodiment 10, wherein the tubular portion is expandable to be circumferentially juxtaposed with the lumen of the blood vessel when the expandable framework is in the expanded configuration. (15) When the expandable framework is in the expanded configuration, the fluid-impermeable membrane comprises a first outer perimeter that is substantially equal to the inner perimeter of the lumen of the outer catheter and a second outer perimeter that is substantially equal to the inner perimeter of the blood vessel, the system of embodiment 10.

[0094] (16) When the expandable framework is in the expanded configuration, at least a portion of the proximal portion of the expandable framework is disposed within the lumen of the outer catheter to provide an outward force on the lumen of the outer catheter, the force being effective to form a fluid-impermeable seal between the fluid-impermeable membrane and the lumen of the outer catheter, the system of embodiment 10. (17) A method of retrieving an occlusion from a patient's blood vessel, accessing the patient's arterial blood vessel using an outer catheter having a lumen therethrough, positioning the distal end of the outer catheter in a proximal direction relative to the occlusion and adjacent to the occlusion, advancing distally through the lumen of the outer catheter a microcatheter and an expandable framework having a fluid-impermeable membrane thereon, the expandable framework being advanced in a collapsed configuration while disposed within the microcatheter, crossing the occlusion with the microcatheter and the expandable framework in the collapsed configuration, retracting the microcatheter into the lumen of the outer catheter while maintaining at least a portion of the expandable framework over the entire occlusion, expanding at least a portion of the expandable framework over the entire occlusion, expanding the distal portion of the membrane to circumferentially juxtapose with the blood vessel, expanding the proximal portion of the membrane to circumferentially juxtapose with the lumen of the outer catheter, A method comprising the step of inhaling through a fluid passage defined by the membrane and the lumen of the outer catheter. (18) The method according to embodiment 17, wherein the outer catheter is advanced to a distance of about 3 millimeters away from the proximal end of the occluder. (19) During inhalation through the fluid passage, at least a portion of the expandable framework is retracted into the lumen of the outer catheter; The method according to embodiment 17, further comprising removing the expandable framework containing an occluder from the patient. (20) The method according to embodiment 17, further comprising injecting a contrast agent into the lumen of the outer catheter to evaluate the extent of the occluder remaining in the blood vessel.

Claims

1. A system for retrieving an occlusion within a blood vessel, comprising: an outer catheter having a lumen therethrough; a blood clot retrieval device disposed within the outer catheter and translatable through the lumen of the outer catheter, the blood clot retrieval device comprising: an elongate flexible member having a distal end; an expandable framework configured to engage the occlusion and expandable from a folded delivery configuration to an expanded configuration, the expandable framework comprising a proximal portion secured to the distal end of the elongate flexible member and a tubular portion extending distally from the proximal portion, the tubular portion having an elongate tubular shape when the expandable framework is in the expanded configuration, and the proximal portion being tapered proximally from the tubular portion to the distal end of the elongate flexible member when the expandable framework is in the expanded configuration; a fluid-impermeable membrane secured to the proximal portion of the expandable framework, the fluid-impermeable membrane including a proximal opening sized to permit intake, the proximal opening of the fluid-impermeable membrane being in communication with the lumen of the outer catheter, and the fluid-impermeable membrane having a funnel shape when the expandable framework is in the expanded configuration; a blood clot retrieval device; and comprising: at least a portion of the proximal portion of the expandable framework being covered by at least a portion of the fluid-impermeable membrane; when the expandable framework is in the expanded configuration, at least a portion of the proximal portion of the expandable framework being disposed within the lumen of the outer catheter and providing an outward force to the lumen of the outer catheter; the force forming a fluid-impermeable seal between the fluid-impermeable membrane and the lumen of the outer catheter.

2. The system of claim 1, wherein most of the tubular portion of the expandable framework is provided with cell apertures sized to pass through the occluder when the expandable framework expands from the folded delivery configuration to the expanded configuration. **Claim 3** The system of claim 1, wherein the expandable framework further comprises a closed distal end portion that extends distally from the tubular portion and radially inwardly to the central axis of the tubular portion. **Claim 4** The system further comprises a microcatheter sized to traverse the lumen of the outer catheter, The system of claim 1, wherein the expandable framework is sized to traverse the lumen of the microcatheter when the expandable framework is in the folded delivery configuration. **Claim 5** The system of claim 1, wherein when the expandable framework is in the expanded configuration, the tubular portion is expandable to be circumferentially juxtaposed with the lumen of the blood vessel. **Claim 6** The system of claim 1, wherein when the expandable framework is in the expanded configuration, the fluid-impermeable membrane comprises a first outer periphery substantially equal to the inner periphery of the lumen of the outer catheter and a second outer periphery substantially equal to the inner periphery of the blood vessel.

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