Hydraulic displacement and removal of thrombus clots, and catheters for performing hydraulic displacement

Abstract

To provide catheters allowing blockage of a vessel with proximal fluid infusion to generate fluidic forces to facilitate clot removal.SOLUTION: Aspiration and hydraulic forces supporting a removal process are used. The hydraulic forces can be generated by occluding a vessel distal to a clot and delivering a liquid to between the clot and an occlusive device. An aspiration catheter is positioned to be proximal to the clot. Catheters designed to facilitate the delivery of the hydraulic forces can be based on single lumen designs or dual lumen designs. The catheters may have a fixed internal wire, or in some embodiments the catheters can progress on a wire with a valve / seal positioned to restrict the flow into or out of a guide lumen such that the guide lumen can further function for balloon inflation and / or for infusion of a liquid.SELECTED DRAWING: Figure 30

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to co-pending U.S. Provisional Patent Application No. 62 / 404,918 by Ogle, entitled “Hydraulic Displacement and Removal of Thrombus Clot,” filed October 6, 2016, which is incorporated herein by reference.

[0002] The present application relates to a procedure that facilitates suction of clots from blood vessels by using fluid force. The present application further relates to a catheter that is designed to be delivered to small blood vessels and allows for occlusion of the vessel by proximal fluid injection to generate fluid force to facilitate clot removal. [Background technology]

[0003] Ischemic attacks can be caused by blood clots in the cerebral arteries. The clots can block blood flow, which can block brain tissue from its blood supply. The clots can be thrombi that occur locally or emboli that have traveled from another location to the site of vascular occlusion, and in either case can be referred to as thrombotic clots while occluding the blood vessel. Time is a critical factor and it can be desirable to restore blood flow in a short time to reduce the effects of the blockage of blood supply to the tissue. The cerebral arterial system is a highly branched vascular system that provides blood to the brain and is connected downstream to the internal carotid artery. The cerebral arteries are highly circuitous. The therapeutic device must be able to navigate along the circuitous path provided by the cerebral arteries in order to be placed in the cerebral arteries. Summary of the Invention [Means for solving the problem]

[0004] In a first aspect, the present invention relates to a method for removing a blood clot from a blood vessel of a patient, the method comprising: occluding the blood vessel with an occlusion element distal to the clot; injecting a liquid between the clot and the occlusion element; aspirating fluid from the blood vessel proximal to the clot with at least some temporary overlap of injection and aspiration to create a fluid force against the clot; Includes.

[0005] In a further aspect, the invention relates to a catheter comprising a tubular shaft with a central lumen and a distal end, a proximal attachment, and a balloon having a proximal end and an interior. Generally, the balloon is attached at or near the distal end of the tubular shaft, and the interior of the balloon is in fluid communication with the central lumen. In some embodiments, the tubular shaft comprises one or more injection ports proximal to the balloon within about 5 centimeters of the proximal end of the balloon.

[0006] In another aspect, the invention relates to a catheter comprising a shaft comprising a tubular element and a proximal fitting, the tubular element having a distal end, a first lumen and a second lumen, and no separate guidewire lumen, and a balloon having a proximal end and an interior secured to an outer surface of the shaft at or near the distal end of the shaft, the interior of the balloon being in fluid communication with the first lumen. In some embodiments, the shaft comprises an injection port proximal to the distal end of the balloon and within about 5 centimeters of the proximal end of the balloon. The injection port can be in fluid communication with the second lumen, and the shaft may be free of an injection port distal to the balloon and an additional balloon. Additionally, the proximal fitting may include a Y-branch fitting providing a first connector for coupling a source of injection fluid for delivery through the injection port and a second connector for coupling a device configured for delivery and / or removal of balloon inflation fluid.

[0007] In a further aspect, the invention relates to a catheter comprising a balloon, a catheter shaft, and a proximal fitting having connections to a source of inflation fluid and an infusate source. In some embodiments, the catheter shaft comprises an injection port, a dual lumen structure having a guidewire lumen and an auxiliary lumen, and a valve configured to close the distal end of the guidewire lumen in the absence of a guidewire. The auxiliary lumen can be in fluid communication with either the interior of the balloon and a connection to a source of inflation fluid or with the injection port and an infusate source. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a treatment system in which a microcatheter adapted for injection is advanced over a fixed wire single lumen balloon catheter. [Diagram 2] 2 is a cross-sectional view of the system of FIG. 1 taken along line 2-2 of FIG. 1. [Diagram 3] FIG. 1 is a side view of a single lumen balloon / infusion catheter with an integrated distal coil. [Figure 4] 4 is a cross-sectional view of the single lumen balloon / infusion catheter of FIG. 3 taken along line 4-4 of FIG. 3. [Diagram 5] FIG. 4 is a partial view of an injection port for the balloon / injection catheter of FIG. 3 covered with an elastomeric valve. [Figure 6] FIG. 1 is a side view of a single lumen balloon / infusion catheter with a fixed inner wire and an integral distal coil. [Figure 7] 7 is a cross-sectional view of the single lumen balloon / infusion catheter of FIG. 6 taken along line 7-7, showing a proximal fixation structure for a fixed wire. [Figure 8] FIG. 13 is a side view of a single lumen balloon / infusion catheter advanced over a guide structure, with the valve / seal near the distal end of the catheter engaging the wire of the guide structure, and the balloon / inset showing a proximal manifold fitting suitable for coupling to the proximal fitting of the catheter. [Figure 9] FIG. 13 is a partial side view of an alternative embodiment of a single lumen balloon / infusion catheter with a fixed wire and a valve over the injection port. [Figure 10] FIG. 10 is a side view of the wire of the single lumen balloon / infusion catheter of FIG. 9 shown separated from the catheter, with the balloon / inset showing a rotated view of the proximal end of the wire having a flattened shape. [Figure 11] FIG. 10 is a side view of the catheter of the single lumen balloon / infusion catheter of FIG. 9 separated from the fixed wire. [Figure 12] 11 is a partial view of the proximal end of the single lumen balloon / infusion catheter of FIG. 9, in which the fitting includes a tubular receiving element that supports the floating end of the flattened wire of FIG. [Figure 13] FIG. 10 is a partial side view of an alternative tip of the single lumen balloon / infusion catheter of FIG. 9, in which the optional coil is replaced with a canon at the wire distal end. [Figure 14] FIG. 1 is a side view of a balloon / infusion catheter with two lumens, an annular injection port, and a fixed wire within the lumen of the inner tubular element. [Figure 15] 15 is a cross-sectional view of the balloon / infusion catheter of FIG. 14 taken along line 15-15 of FIG. 14, showing a crimped portion of the outer tubular element to secure the outer tubular element to the inner tubular element. [Figure 16] FIG. 1 is a side view of a balloon / infusion catheter having a co-extruded unitary element with two lumens, with the proximal and distal ends offset to allow the structure to be shown in greater detail, while the long unchanging structure of the shaft is omitted from the view. [Figure 17] FIG. 17 is a cross-sectional view of the balloon / infusion catheter of FIG. 16 taken along line 17-17, showing the two lumens and the fixed wire. [Figure 18] FIG. 1 is a side view of a balloon / infusion catheter with two lumens and a distal valve / seal to allow the catheter to move over a guide structure, with the guide lumen combined with the balloon lumen. [Figure 19] FIG. 1 is a side view of a balloon / infusion catheter with two lumens and a distal valve / seal to allow the catheter to move over a guide structure, with the guide lumen combined with the infusion lumen. [Figure 20] FIG. 13 is a front view of an embodiment of a valve / seal engaging a guide structure, the valve / seal comprising three leaflets. [Figure 21] FIG. 13 is a partial side view of an alternative embodiment of a valve / seal engaging a guide structure with a central hole that seals the guide structure closed in the absence of the guide structure. [Figure 22] FIG. 22 is a partial side view of the valve / seal of FIG. 21 with a guide structure passing through the valve / seal. [Figure 23] FIG. 1 is a partial perspective view of a section of a catheter wall having metal reinforcing wires embedded within the polymer wall. [Figure 24] 1A-1C are schematic diagrams illustrating process steps for forming an embodiment of a catheter comprising a metal braid and / or metal coil embedded within a polymeric tubular element. [Diagram 25] FIG. 1 is a schematic diagram showing components of a treatment system based on the use of a balloon / infusion catheter with an aspiration catheter useful for the treatment of acute ischemic stroke. [Figure 26] FIG. 2 is a side view of a guide catheter. [Figure 27] FIG. 1 is a side view of an aspiration catheter with a thin distal tip. [Figure 28] FIG. 1 is a side view of an aspiration system with a suction nozzle in a guide catheter and corresponding proximal fitting with a flow manifold. [Figure 29] FIG. 1 is a schematic diagram of a patient illustrating delivery of a stroke treatment system via percutaneous intrafemoral artery access. [Diagram 30] FIG. 1 is a partial view of a balloon / infusion catheter deployed within a patient's vessel and an aspiration catheter positioned to establish fluid force to push the clot in a distal to proximal direction toward the aspiration catheter. [Diagram 31] A partial view of a portion of the carotid artery with a distal end of a guide catheter positioned within the carotid artery and a guidewire extending from the guide catheter into a cerebral artery, with the distal end of the guidewire extending beyond the clot. [Diagram 32]FIG. 32 is a partial view of the cerebral artery of FIG. 31 , in which a microcatheter has been delivered over the guidewire such that the distal end of the microcatheter extends beyond the clot. [Diagram 33] FIG. 33 is a partial view of the cerebral artery of FIG. 32 with the aspiration catheter in place and the guidewire removed and replaced with a balloon / injection catheter, with the balloon uninflated. [Diagram 34] FIG. 34 is a partial view of the carotid artery of FIG. 33 with the balloon of the balloon / infusion catheter inflated. [Diagram 35] FIG. 35 is a partial view of the cerebral artery of FIG. 34 in which hydraulic forces are established by aspiration and injection, resulting in displacement of the thrombus from the clot in the proximal direction. [Diagram 36] FIG. 36 is a partial view of the cerebral artery of FIG. 35, in which thrombus from the clot has reached the aspiration opening of the aspiration catheter. [Figure 37] FIG. 37 is a partial view of the cerebral artery of FIG. 36 with the balloon at least partially deflated and the microcatheter and balloon / injection catheter removed from the vessel. [Figure 38] FIG. 35 is a fragmentary view showing an alternative portion of the procedure in which a balloon / injection catheter is delivered over a guidewire as an alternative to the step leading to the configuration shown in FIG. 34. [Figure 39] FIG. 33 is a partial view of the cerebral artery shown in FIG. 32 in which an alternative procedure involves removal of the guidewire and replacing it with a guide structure supporting a fiber-based filter. [Diagram 40] FIG. 40 is a partial view of the cerebral artery of FIG. 39 with the fiber-based filter deployed and the balloon / infusion catheter moved over the guide structure and into position. [Diagram 41] FIG. 41 is a partial view of the cerebral artery of FIG. 40 in which the balloon is inflated, the filter is deployed, and hydraulic forces are established by suction and injection, resulting in proximal displacement of the thrombus from the clot. [Diagram 42] FIG. 42 is a partial view of the cerebral artery of FIG. 41 with the thrombus reaching the distal opening and entering the aspiration catheter and the balloon at least partially deflated in preparation for removing the device from the vessel. [Diagram 43] FIG. 43 is a partial view of the cerebral artery of FIG. 42, in which the microcatheter, balloon / infusion catheter and deployed filter are moved toward an aspiration catheter for removal from the patient's body, and the deployed filter is used to sweep the vessel on its way to be removed. [Diagram 44] FIG. 1 is a partial view of a cerebral artery with a guide catheter positioned within the carotid artery such that the deployed balloon is near the distal end of the guide catheter and a balloon / infusion catheter extending from the guide catheter such that the deployed balloon is positioned distal to the clot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Devices and corresponding methods are described that use a combination of suction and liquid injection to perform clot removal in arteries, loosening the clot with moderate force against the vessel wall. Fluid forces generated by flow from a distal injection to the aspiration catheter relative to the clot location can push the clot in a distal to proximal direction for removal. Generally, a distal balloon or other occlusion device can be expanded to close the vessel at a location beyond the clot, directing the infusion fluid back toward the aspiration catheter in a proximal direction. The use of infusion fluid can reduce the force on the vessel generated by aspiration from the vessel. And, the treatment system can include ancillary devices to facilitate the procedure, such as guidewires, guide catheters, and / or other devices, along with the distal occlusion balloon, injection device, and aspiration catheter. Described herein are single and dual lumen balloon catheters designed to perform the injection required for fluid-assisted procedures. Fluid-based clot removal systems can provide a desirable alternative to other medical clot removal systems. Fluid, hydraulic and / or hydrodynamic forces may tend to prevent significant vessel collapse caused by suction, to dilate the vessel and loosen the clot, removing the clot without significant abrasion of the vessel wall. These procedures and corresponding devices may be designed to be used to address acute ischemic stroke in tortuous cerebral arteries.

[0010] Various methods have been developed to remove clots in arteries, especially in the setting of acute stroke. Various clot-engaging instruments are commercially available, and suction catheters are also available to facilitate clot removal. The procedure described herein provides an alternative to mechanical engagement of the clot, which may result in clot fragmentation and / or abrasion of the vessel wall. The procedure also provides an alternative to the introduction of suction alone, which may result in large pressure fluctuations within the vessel, which may also damage the vessel wall or other walls adjacent to the vessel. The use of suction without injection also tends to reduce local vessel pressure, which may tend to reduce vessel diameter, thereby preventing removal of the clot by collapsing the vessel around the clot. Recently, the use of fluid profusion (perfusion) along with suction to reduce the occurrence of large pressure drops was described in U.S. Patent Application Publication No. 2017 / 0056061 A1 by Ogle et al., entitled “Thrombectomy Devices and Treatment of Acute Ischemic Stroke With Thrombus Engagement” (hereinafter the '061 application), which is incorporated herein by reference.

[0011] Less invasive procedures, commonly referred to in the art as minimally invasive procedures, are desirable in medical settings to reduce patient recovery time and hopefully improve outcomes when appropriate. In particular, minimally invasive procedures are generally performed in the vasculature using catheter-based systems to reach distant locations within selected blood vessels for the implementation of various therapeutic processes. These procedures may also be referred to as percutaneous or transvascular procedures, as opposed to open procedures, to emphasize delivery through the vascular lumen. The discussion herein focuses on the treatment of ischemic stroke, as the device may be effective for treating these clinically significant conditions. However, the device may be used for other procedures in both the vasculature and other body vessels. Patients include humans and may include other animals, including pets and livestock. The terms proximal and distal are used with their conventional meaning in the art, i.e., proximal refers closer to the point of entry into the patient's body along a pathway in the vasculature or other vessel, and distal refers farther from the point of entry along a pathway in the vasculature.

[0012] For stroke treatment, the treatment device is advanced through the arteries to the blood vessels of the brain. The blood vessels generally associated with acute stroke treatment are downstream from the internal carotid artery in the bloodstream, and the arteries generally branch and reduce in average diameter as the vessels progress downstream through the arterial vasculature. The body has a right internal carotid artery and a left internal carotid artery. For convenience, the blood vessels downstream from the internal carotid artery are referred to herein as the cerebral arteries. The cerebral arteries can be accessed by catheter-based systems, for example, from the femoral artery in the groin, the arteries in the arm, or the carotid artery in the neck, using hemostatic procedures and appropriate fittings, such as those known in the art. The cerebral arteries are known to follow a circuitous path, and with the reduction in diameter and branching of the vessels distally from the carotid artery, complications of tracking the device along the vessels also result, possibly due to risk conditions from injury to the vessels. For stroke treatment, it may be desirable to access small, tortuous arteries. Although the devices described herein are designed for advantageous use in these small and tortuous cerebral arteries, those skilled in the art will appreciate the utility of these devices in other medical procedures.

[0013] As described herein, the fluidic aspect of the process is further emphasized through distal occlusion of blood vessels combined with distal profusion, perfusion to provide for the establishment of flow from a location distal to the clot to a proximally positioned opening in the aspiration catheter to facilitate the displacement and removal of the clot using hydraulic forces. In some embodiments, a microcatheter can be used in combination with an appropriately small balloon catheter to perform procedures in which fluid is injected between the microcatheter and the balloon catheter body. Specially designed devices can be advantageously used to perform procedures and can be single-lumen or dual-lumen based. In single-lumen catheter embodiments, the catheter can have an integrated wire to provide the desired mechanical performance without an associated wire, or the catheter can be advanced over a separate guidewire with structures (seals and / or valves) to block flow from the lumen distal to the balloon. The single lumen functions for both infusion and balloon inflation. In dual-lumen devices, the wire again can be integral or separate with appropriate flow-restricting structures. Separate lumens may be used for balloon inflation and fluid infusion, and for appropriate embodiments, the guidewire lumen may be combined with either the balloon lumen or the infusion lumen. Although non-balloon closure devices may be used to perform the hydraulically assisted procedures described herein, the discussion herein will focus on balloon configurations that can provide the desired performance in the procedures described herein and simple disengagement for removal.

[0014] The basic aspects of the procedure described herein include the placement of an aspiration catheter with an occlusion balloon distal to the clot, an injection port between the occlusion balloon and the clot, and a suction opening proximal to the clot. The occlusion balloon is highly compliant, i.e., formed from an elastic material, and capable of occluding the vessel with moderate force against the vessel wall. Suitable guidewires, microcatheters, and aspiration catheters for use in the neurovasculature are described below and are also described in detail in U.S. Patent Application Publication No. 2016 / 0199620 to Pokorney et al., entitled "Medical Guidewires for Tortuous Vessels," and the '202 application, both of which are incorporated herein by reference. Commercially available high-compliance balloons approved for the neurovasculature include, for example, TransForm® (Stryker Neurovacular), Specter C or XC® (Microvention / Terumo), Hyperform™ (Covidien), or Ascent® (DePuy Synthes / Codman Neurovascular). However, these balloons have larger diameters than are desired for the procedures described herein for many vessels. For smaller profile balloons, similar designs with correspondingly smaller components can be used to provide the desired functionality. Guidewires and, in some embodiments, microcatheters, can provide access to the vessel distal to the clot and maintain access to the area distal to the clot for proper placement of the balloon / infusion catheter at the distal location to the clot.

[0015] Injection of liquid together with suction can generate a flow of liquid from distal to proximal to the clot with corresponding generation of hydraulic and / or hydrodynamic forces. For convenience, the force generated in the procedure is referred to herein as hydraulic force, which in some sense can include hydraulic force, hydrodynamic force or a combination thereof. By initiating injection prior to suction and / or controlling the various flow rates, the local pressure within the vessel can be somewhat increased, and a moderate increase in such pressure can flex the vessel in a manner that may loosen the vessel wall's grip on the clot. Thus, both balloon expansion and pressure control can act to loosen the clot to facilitate its removal. The force against the vessel wall should be controlled to avoid damage to the vessel wall. The distal to proximal flow of liquid correspondingly exerts a distal to proximal force against the clot that tends to move it towards the aspiration catheter. The objective is to either push the clot away so that it can be sucked up by the aspiration catheter, or to carry the clot to the aspiration opening for removal from the patient's body by the catheter.

[0016] The procedure can be performed by a treatment system assembled from a balloon catheter, an injection catheter (which can be combined with the balloon catheter into a single device), an aspiration catheter, and optionally other devices suitable for the neurovasculature or other corresponding vessels. For use in the neurovasculature, it is generally desirable to use a separate guidewire to facilitate reaching more remote sites in the vessel, but the guidewire may move as additional components are delivered near the treatment site. To guide the procedure, a guide catheter is generally placed in the carotid artery, e.g., the internal carotid artery or the common carotid artery, through which additional devices can be guided to smaller vessels downstream. The guide catheter can include a hemostatic valve for introducing additional devices. In some embodiments, the guide catheter can also have an occlusion balloon that can be activated to block flow through the balloon. It may be desirable to stop the flow for at least a portion of the procedure. Also, as an alternative or in addition to the use of a separate aspiration catheter, suction can optionally be applied through the guide catheter.

[0017] Although existing devices can be used to perform some of the procedures described herein in at least some vessels, desirable device designs are described that offer advantages in terms of designing the device to provide the desired hydrodynamic flow with simplicity of implementation. The new devices described herein have a common feature of an injection port positioned proximally to the balloon along the shaft. Some catheter embodiments have a single lumen for both infusate and balloon expansion. Other catheter embodiments have two lumens that are separate lumens for balloon inflation and deflation as well as infusion. Catheter designs with a single lumen generally include simpler structures with similar construction materials and potentially smaller diameters. Catheter designs with two lumens offer the additional ability to use different fluid pressures for infusion with respect to balloon inflation pressure and to adjust the volume of delivered fluid to infuse. The catheter designs may have no associated wire structure, or may have an integral wire to control the flexibility and steerability of the catheter, or may be advanced over a separate guide structure, e.g., a guidewire, using a flow control structure that maintains liquid within the catheter so that the guidewire lumen can serve a dual role. Catheter embodiments that share a guidewire lumen with another functional lumen may utilize lumen volume more efficiently to facilitate achieving a desired device size.

[0018] For use in the neurovasculature, the small diameter of the vessels generally imposes significant constraints on the device. When delivering multiple coaxes, the available lumen size of the outer device is effectively constrained by the blocked space occupied by the inner device. Therefore, it may be desirable to design a dedicated device to perform the improved procedures described herein so that the limited lumen volume can be used more effectively. An occlusion balloon catheter with infusion capabilities is described in U.S. Patent Application Publication No. 2013 / 0245552 by Ogle et al., entitled "Vascular Medical Devices with Sealing Elements and Procedures for the Treatment of Isolated Vessel Sections," which is incorporated herein by reference. However, the device in the '552 application is intended for use in large vessels and is not designed to fit within small vessels, such as some of the neurovasculature. The introduction of a separate guidewire lumen consumes a significant amount of the device's internal space as the walls form a separate lumen, and correspondingly, the loss of internal volume limits the available size of the separate profusion, perfusion or infusion lumen.

[0019] In a specific catheter embodiment herein, the balloon lumen can be combined with the guidewire lumen. If the guide structure is left in place, the guidewire itself can shrink to a reasonably small value or function as an obturator that eliminates the exchange of blood flow into the balloon during delivery of the catheter and fluid from the lumen when the balloon is inflated. A catheter with a guidewire lumen shared with the balloon lumen, with a valve to close the guidewire lumen, is described in U.S. Patent No. 6,306,124 to Jones et al., entitled "Microcatheter," which is incorporated herein by reference. The '124 patent described a balloon catheter with a very small diameter, down to less than a millimeter. The presence of a flow control structure, such as a valve or diaphragm, can allow removal of the guidewire while blocking flow into the corresponding lumen.

[0020] The use of suction alone has provided promising results for the treatment of acute ischemic stroke. Alternative devices are available that mechanically dislodge the stroke-causing clot, and these devices can be called stent retrievers, although some of these devices are not entirely derivatives of stents. It is also possible to use suction with stent retrievers and the like to provide a combined effect of the approach. Furthermore, while suction can be very effective, the degree of suction provided for effective clot removal can deplete blood from a portion of the vessel, resulting in significant collapse forces on the vessel and corresponding forces on adjacent tissue, which may be undesirable in some cases. While suction can be effective to dislodge and remove the clot, collapse of the vessel around the clot due to liquid removal may not facilitate the process and may increase the corresponding forces. The hydraulic / hydrodynamic forces described herein generate forces on either side of the clot that tend to dislodge the clot, but also tend to distend the vessel to loosen the clot. Thus, procedures can be designed to reduce the extreme forces within the vessel and on the surrounding tissue while potentially being even more effective at removing the clot.

[0021] Aspiration or suction catheters are available to provide suction for the hydraulically assisted procedures described herein, and are described in detail below. Aspiration catheters can be effectively used with catheters that provide occlusion and infusion, and optionally with additional therapeutic devices, such as clot-engaging mechanical and / or filter-type devices that can capture loose emboli and, optionally, engage the clot with a more cushioned element to limit force against the vessel wall. Various systems for clot treatment are described below. Whether used alone to provide hydraulic therapy or in combination with additional therapeutic or protective devices, the hydraulic therapy procedures described herein provide an important tool with the potential to provide a more gentile, gentle removal of clots from blood vessels, which may be particularly effective in mitigating acute ischemic stroke.

[0022] Catheter providing closure and infusion Specific catheter configurations are described that provide distal flow occlusion and proximal fluid delivery, for example, by a balloon, to generate desired fluid forces against the clot in a distal to proximal direction within the vessel. Common features of the devices are closure elements and injection ports that can be configured in various configurations. The catheters are intended for use with aspiration catheters and, optionally, other devices that facilitate the use of the catheter and / or complement the treatment of the vessel, and the device systems and procedures are discussed in the following sections. To perform the occlusion and injection functions, the catheters can have one or two lumens, and generally do not have additional lumens extending from near the distal end of the catheter to the proximal end of the catheter. To give the catheter the desired mechanical properties, the catheters can have an integral wire, or the catheters can be designed to go over a guidewire with flow control structures to isolate the guidewire lumen from the vascular fluid. Balloon catheters that can also provide injection can be conveniently referred to as balloon / injection catheters.

[0023] Referring to FIG. 1, a catheter system 100 includes a fixed wire single lumen occlusion balloon catheter 102 (hereafter balloon catheter 102) and a microcatheter 104. As shown in FIG. 1, the balloon catheter 102 is configured to be delivered through the microcatheter 104. The balloon catheter 102 includes a spring tip 110, a tubular shaft 112 forming a lumen 114 from which the spring tip 110 extends at a distal end, a balloon 116, a fixed wire 118 fixed within the lumen 114, and a proximal attachment 120. The balloon 116 may be a highly compliant balloon and has an interior in fluid communication with the lumen 114 such that the balloon 116 can be inflated or deflated by adjusting the fluid pressure within the lumen 114. The fixed wire 118 inside the catheter may provide similar features as a guidewire for the catheter, and the spring tip 110 may be optional as long as the catheter tip is configured to avoid damage to the vessel wall. FIG. 2 shows a cross-sectional view including various positions of the components. Delivering the balloon catheter 102 through a microcatheter 104 can facilitate maneuvering the distal tip of the balloon catheter into small, tortuous blood vessels.

[0024] The microcatheter 104 comprises a tubular shaft 130 and a proximal fitting 132. The tubular shaft 130 can generally be designed to have an inner diameter sufficiently larger than the outer diameter of the tubular shaft 112 of the balloon catheter 102 to allow the balloon catheter 102 to move within the microcatheter 104 and to allow infusion fluid to be delivered through a space 134 between the tubular shaft 130 and the tubular shaft 112. A suitable range of catheter dimensions is described below. In FIG. 1, delivery of infusion fluid 136 is shown diagrammatically. Generally, suitable fittings for the fittings 120, 132 are known in the art. In particular, the fittings 120, 132 can be luer fittings, such as female luer fittings, Tuohy-Borst connectors, and the like. The luer connectors or Tuohy-Borst connectors can be useful for connecting standard or proprietary fittings or manifolds, such as Y-junction fittings, to provide the desired access to the lumen.

[0025] Although the combined device of Figure 1 includes two separate components, in a sense the combined device provides two separate lumens, one for infusion and the second lumen acting as the balloon lumen. Single lumen catheter embodiments can provide balloon inflation / deflation with associated infusion using a common lumen. Figures 3-8 show three embodiments of single lumen balloon / infusion catheters, each without a wire, with a fixed wire, or with a separate guidewire.

[0026] Referring to FIG. 3, an embodiment of a balloon / infusion catheter 150 is shown without wires, with the catheter body providing the mechanical properties of the catheter. The balloon / infusion catheter 150 comprises a tubular shaft 152, an optional coil tip 154 ​​extending distally from the tubular shaft 152, a balloon 156, and a proximal attachment 158 ​​at the proximal end of the tubular shaft 152. General details of materials and dimensions of components are described below. The tubular shaft 152 comprises a lumen 160 extending from the proximal attachment 158 ​​to the balloon 156. The lumen 160 is generally closed at its distal end at or near the coil tip 154. In the absence of the coil tip 154, the distal end of the catheter can be shaped to avoid damage to the vessel wall. A suitable opening 162 provides fluid communication between the lumen 160 and the interior of the balloon 156. 4, four openings 164 distributed around the circumference of the tubular shaft 152 provide fluid communication between the lumen 160 and the interior of the balloon 156. The balloon 156 can be sealed around two sections of the shaft (one proximal and one distal) to define an interior 166 and an exterior 168 of the balloon, where the balloon interior is isolated from the external fluid environment.

[0027] One or more injection ports 170 allow for the infusion of fluid from lumen 160 into the patient's vasculature, delivered from a fluid source coupled to proximal fitting 158. The flow of fluid out of lumen 160 tends to reduce the pressure within the lumen. Fluid pressure within lumen 160 also allows for inflation of balloon 156. The fluid dynamics should be balanced such that adequate pressure maintains an inflated balloon while correspondingly providing the desired infusion flow rate. Infusion ports 170 can be designed accordingly and are appropriately proximal to balloon 156 to facilitate placement distal to the clot in tortuous vessels. In particular, the size and number of injection ports 170 can be selected to provide adequate infusion at pressures that inflate balloon 156. In some embodiments, the furthest edge of the injection port is 5 centimeters or less from the nearest edge of the balloon, and in further embodiments, 2.5 centimeters or less, this spacing being inclusive for all of the catheter embodiments in this section. A person of ordinary skill in the art will recognize that additional values ​​of injection port spacing within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0028] Also shown in FIG. 5 is an embodiment of an injection structure in which an elastic cover 172 covers the injection port 170. The elastic cover 172 can provide an additional means of control over the injection process, where a predetermined amount of pressure can be applied to inflate the elastic cover 172 to provide the injection. The elastic cover 172 can be sealed to the tubular shaft 152 along one edge and open at the opposite edge to allow injection. Arrows in FIG. 5 are shown to diagrammatically illustrate injection through the unsealed edge. The elastic cover 172 can be made from the same or similar material as the balloon 156, but can also be made from a separate material so long as it provides the desired elastic properties.

[0029] FIG. 6 illustrates an alternative embodiment of a balloon / infusion catheter 180 having a single lumen. The balloon / infusion catheter 180 includes a tubular shaft 182, an optional coil tip 184 extending distally from the tubular shaft 182, a balloon 186, a fixed wire 188, and a proximal fitting 190 at the proximal end of the tubular shaft 182. General details of the materials and dimensions of the components are described below. The balloon / infusion catheter 180 is similar in construction to the balloon / infusion catheter 150, except for the inclusion of the fixed wire 188. The tubular shaft 182 includes a lumen 192, an opening 194 that provides a fluid connection between the lumen 192 and the interior of the balloon 186, and an infusion port 196 that provides for liquid flow out of the lumen 192. The features of the opening 194 and the infusion port 196 can be consistent with those described above in connection with FIG. 3 for the corresponding opening 162 and infusion port 170, including but not limited to the alternative embodiments of FIGS. 4 and 5. The fixed wires 188 can be secured at or near their respective ends within the lumen 192. With reference to FIG. 6, the distal ends 198 of the fixed wires 188 can be secured at the structure terminating lumen 192 and the fastening coil tip 184 or alternative tip, such structure can include, for example, an adhesive plug or the like, which may be further secured with a radiopaque band 200 or the like. A clip or scaffold 202 can be secured within the lumen 192 to support the fixed wires 188. Alternative embodiments having floating wire proximal ends are described below. The scaffold 202 can have any reasonable structure that provides for liquid flow past the scaffold within the lumen 192. With reference to FIG. 7, a scaffold is shown with arms 204 that hold the fixed wires 188 in place.

[0030] 8 shows an embodiment of a single lumen balloon / infusion catheter 210 that is advanced over a guide structure 212, such as a guidewire. The balloon / infusion catheter 210 comprises a tubular shaft 214, an optional coil tip 216 extending distally from the tubular shaft 214, a balloon 218, and a proximal fitting 220 at the proximal end of the tubular shaft 214. General details of the materials and dimensions of the components are provided below. The balloon / infusion catheter 210 is similar in structure to the balloon / infusion catheter 150, except for the structure for accommodating the interface with the guide structure 212. The tubular shaft 214 comprises a lumen 222, an opening 224 that provides a fluid connection between the lumen 222 and the interior of the balloon 218, and an infusion port 226 that provides for liquid flow out of the lumen 222. The features of the opening 224 and the injection port 226 can be consistent with those described above in connection with FIG. 3 for the corresponding opening 162 and injection port 170, including but not limited to the alternative embodiments of FIG. 4 and FIG. 5. The guide structure 212 can be a guidewire or other structure, such as a wire-based filter structure, with suitable guide structures described further below. The tubular shaft 214 can include a flow control structure 228 that provides for movement of the tubular shaft 214 relative to the guide structure 212 with little or no fluid exchange from the lumen 222 into or out of the distal end of the tubular shaft 214. Suitable structures for the flow control structure 228 are described further below. The proximal fitting 220 can have a female Luer connector or a Tuohy-Borst connector, or the like, for connection to additional attachment components, such as the Y-branch manifold 230 shown on the balloon in FIG. 8. The Y-branch manifold 230 has a side arm 234 with a connector 236, such as a female Luer connector 232, Luer connector, or the like, for connecting to a fluid source and a hemostatic valve 238 that provides relative movement of the balloon / infusion catheter 210 and the guide structure 212 so that there is little or no bleeding when the distal portion of the device is within the patient's vasculature, although other fitting configurations can be used as will be appreciated by those skilled in the art.

[0031] 9-11 show a specific embodiment of a balloon / infusion catheter 250 with a single lumen and fixed wire. In particular, FIG. 9 shows the assembled structure, FIG. 10 shows the separate wire, and FIG. 11 shows the separate catheter. With reference to FIG. 9, the balloon / infusion catheter 250 comprises a catheter body 252 and a fixed wire 254. As shown in FIGS. 9 and 11, the catheter body 252 comprises a distal segment 256, a tapered segment 258, and a proximal segment 260. The distal segment 256 and the proximal segment 260 have approximately constant diameters, while the tapered segment 258 transitions between the diameter of the distal segment 256 and the diameter of the proximal segment 260. The tapered segment 258 can have a generally linear taper or other moderately curved taper. The distal segment 256 comprises an infusion port 262 and two openings 264 that provide for the flow of liquid into and out of the balloon 266. The balloon 266 is sealed to the distal segment 256 along two edges to isolate the interior of the balloon 266. An elastic cover 268 covers the injection port 262 to act as a valve that opens to allow injection at sufficient pressure in the lumen 270 inside the catheter body 252.

[0032] 9 and 10, the fixed wire 254 includes a proximal section 280, seven sequentially tapered sections 282, 283, 284, 285, 286, 287, 288, and a distal coil 290. Although FIGS. 9 and 10 show a fixed wire with many sequentially tapered sections, a fewer number of tapered sections, such as one, two, three, four, five, or six, can be used, and more tapered sections can be used if desired. The sections of the fixed wire 254 can have approximately discontinuous diameter changes or desired wire tapers connecting adjacent sections of the tapered sections 282-288. A plug 292, such as an adhesive plug or a polymer plug, can be disposed at the proximal end of the distal coil 290 to help secure the fixed wire 254 to the catheter body 252 to isolate the lumen within the catheter body 252. With reference to Figure 9, the distal coil 290 can have a capped tip 294. Figure 13 shows an alternative embodiment in which the fixed wire 320 is secured by a plug 292 such that the fixed wire 320 terminates in a blunt tip 322 without a coil while avoiding damage to the vessel wall.

[0033] In the embodiment of FIG. 10, the distal end 300 of the fixed wire 254 is flattened, as shown in the inset perpendicular to the continuous view. As shown in FIG. 12, the proximal end of the catheter body 252 can include a proximal attachment 302, which includes an oval receiving tube 304 and a Tuohy-Borst connector or other suitable connector 308 within a body portion 306. The oval receiving tube 304 is shaped to receive the flattened distal end 300, which is raised in the sense that it is not rigidly fixed in any direction along its length. The body portion 306 can be used to grip and manipulate the device so that the user can rotate or slide the balloon / infusion catheter 250 as appropriate. The proximal attachment 302 can be secured to the catheter body 252 using any suitable technique, such as, for example, heat bonding, adhesive bonding, molding, or a combination thereof.

[0034] For use in the neurovascular system, appropriate ranges of dimensions for the components of the balloon / infusion catheter may be specified. The following dimensions refer specifically to the balloon / infusion catheter embodiment of Figures 9-12, but the values ​​may also be applicable to the embodiment of Figures 1-8. The length of the catheter body 252 may be 150 cm to 250 cm, with a particular embodiment having a length of 185 cm ± 1 cm. The distal segment 256 may have a length of about 15 cm to about 50 cm, with a particular value being 23 cm, and the tapered segment may have a length of about 15 cm to about 3 cm, with a particular value being about 7 cm. The catheter body 252 may have a wall thickness of about 0.0015 inches to about 0.0035 inches (materials and processing are described further below), with a particular embodiment being 0.0025 inches, whereby the inner diameter is about 0.005 inches less than the outer diameter (twice the wall thickness). The proximal outer diameter can be from about 0.025 inches to about 0.015 inches, with a particular embodiment having a value of 0.019 inches, and the distal outer diameter can be from about 0.020 inches to about 0.012 inches, with a particular value being 0.015 inches. The inner diameter is determined by the outer diameter and the wall thickness. A person of ordinary skill in the art will recognize that additional ranges within the explicit ranges above are contemplated and are within the present disclosure.

[0035] The fixed wire 254 can extend beyond the distal end of the catheter body 252, such that at least a portion or all of the distal coil 290 extends over the portion of the fixed wire 254 that protrudes beyond the plug 292. The portion of the fixed wire 254 extending beyond the end of the catheter body 252 indicates a length of the fixed wire relative to the catheter body 252. Proximally, the fixed wire 254 can terminate before the proximal end of the catheter body 252, as shown in the embodiment of FIG. 6, while in the embodiment shown in FIG. 12, the fixed wire 254 extends beyond the proximal end of the catheter body 252. Thus, as shown in FIGS. 8-12, the fixed wire 254 generally has a length somewhat greater than the catheter body 252. The proximal end of the fixed wire 254 can have a diameter of about 0.007 inches to about 0.012 inches, and in some embodiments, about 0.009 inches. The distal most tapered section may have a diameter of about 0.0025 inches to about 0.06 inches, in some embodiments about 0.004 inches. The tapered portion of the fixed wire 254, i.e., the portion extending distally from the proximal section 280, not including any portion extending below the distal coil 290, may have an overall length of about 25 cm to about 70 cm, and it may include multiple segments of different diameters. Along the length of the balloon / infusion catheter 250, the difference between the fixed wire diameter and the catheter inner diameter provides a gap for fluid flow that provides both balloon inflation and infusion control. The gap may not be constant over its length. The gap along the proximal section of the fixed wire 254 may be about 0.003 inches to about 0.007 inches, and in some embodiments, the proximal gap may be about 0.005 inches. The gap in the distal most section of the fixed wire 254 can be from about 0.005 inches to about 0.0089 inches, and in some embodiments, about 0.007 inches. The balloon 266 and injection port 262 can be located along the distal fixed wire section, where a larger gap may be desirable for flow considerations in this region. An intermediate region along the length of the catheter can have a narrower gap.A person of ordinary skill in the art will recognize that additional ranges of length, diameter and gap within the explicit ranges above are contemplated and are within the present disclosure.

[0036] 14-22 show several embodiments of dual lumen balloon / infusion catheters. These catheters share the common feature of having only two lumens rather than three, and the design provides for infusion proximal to the balloon rather than distal to the balloon. Thus, the design can provide a small diameter device that is particularly suitable for the procedures described herein.

[0037] The first dual lumen design provides a unitary structure with an axial annular injection port similar to the injection port formed by separate components in the system of FIG. 1. Referring to FIG. 14, a balloon / infusion catheter 350 includes an inner tubular element 352, an outer tubular element 354, an optional fixed wire 356, an optional distal coil 358, and a proximal fitting 360. In use, the injection fluid flows through the gap between the inner diameter of the outer tubular element 354 and the outer diameter of the inner tubular element 352. As shown in FIG. 14, the proximal fitting 360 includes a Y-branch manifold 362 with a terminal connector 364 and a proximal connector 366. Although the proximal fitting 360 is shown as a particular embodiment as an integral part connecting the outer tubular element 354 with the inner tubular element 352, various alternative structures can be used so long as the proximal fitting 360 has the appropriate manifold structure and corresponding connectors. The fixed wire 356 can be secured at its distal end by an adhesive plug, polymer plug, or the like, and can be raised at its proximal end using a structure such as that shown in FIG. 12, or can be secured at its proximal end using a clip or the like that provides for maintenance of flow while securing the fixed wire.

[0038] The inner tubular element 352 and the outer tubular element 354 may be secured only at the proximal fitting 360 such that the outer tubular element 354 floats from the inner tubular element 352 over the majority of their length. In other embodiments, the inner tubular element 352 may be secured to the outer tubular element 354 at one or more locations along the length of the shaft. The connector securing the inner tubular element 352 and the outer tubular element 354 should not significantly impede flow between the tubes. Referring to FIG. 15, a cross-sectional view of the balloon / infusion catheter 350 shows four crimps 370 on the outer tubular element 354 that secure the inner tubular element 352. Heat may be used to soften the polymer of the outer tubular element 354 to provide the crimps. Additionally or alternatively, rivets 372 or other suitable fasteners may be used to secure the outer tubular element 354 to the inner tubular element 352, as shown in FIG. 14. Similarly, a clip 374 or the like can be placed on the distal end of the outer tubular element 354 to secure the shaft at the injection opening. The connection between the outer tubular element 354 and the inner tubular element 352 can be located at one, two, three or more positions along its length.

[0039] 16 and 17 show an embodiment of a balloon / infusion catheter 400 having two co-extruded lumens. The balloon / infusion catheter 400 comprises a two-lumen shaft 402, an optional wire 404, a proximal attachment 406, and a balloon 408. Referring to the cross-sectional view of FIG. 17, the two-lumen shaft 402 has a balloon lumen 410, which also serves as a wire lumen, and an infusion lumen 412. The balloon lumen 410 can be circular or elliptical as shown. The infusion lumen 412 is shown to have an arch shape, but the shape of the extruded infusion lumen can be selected from any reasonable options. A polymer can be co-extruded to form the two-lumen shaft 402, to which the proximal attachment is later coupled. The wire 404 can be a fixed or sliding wire, and the fixation element 414 can be a wire, or a polymer or adhesive plug or other structure that fixes a valve, seal, or alternative structure that restricts flow around the movable wire. The adhesive or polymer plug is described above in connection with Figs. 1, 3 and 6, and the valve, seal or other flow control structure is further described in connection with Figs. 18-22 as follows, and these discussions may be correspondingly related to the devices of Figs. 16 and 17. The wire 404 may have an optional coil 416 at its distal end. A proximal fitting 406 may be secured to the proximal end of the distal dual lumen shaft 402. The interior of the balloon 408 is in fluid communication with the balloon lumen 410, such as through an opening 418, as shown in Fig. 16. The proximal fitting 406 may include a Y-branch manifold 420 in fluid communication with the infusion lumen 412, and a connector 422 may be disposed at the end of the Y-branch manifold 420. The proximal end of the proximal fitting 406 may include another connector 424. The proximal attachment 406 may include a receiving tube as shown in FIG. 12 to support a floating fixation wire, or a clip or other fastener in the proximal attachment 406 or the distal dual-lumen shaft 402 may secure the fixation wire, or a slidable wire may extend proximally from the connector 424.

[0040] 18-22, an alternative embodiment of a dual lumen catheter for delivery over a guidewire without delivery from a microcatheter is described. With reference to FIG. 18, a dual lumen catheter 450 includes an inner shaft 452, an outer shaft 454, a balloon 456, and a proximal fitting 458. An infusion lumen 460 is formed within the outer shaft 454 around the outside of the inner shaft 452. The inner shaft 452 has a lumen 470 that functions as a balloon lumen and a guide lumen. The inner shaft 452 further includes a valve 472 within the lumen 470 near the distal end of the inner shaft 452 to restrict liquid flow past the valve 472. Generally, a guide structure extends the length of the dual lumen catheter 450 and extends distally from the end of the catheter through the valve 472, again restricting the passage of liquid in either direction through the valve. The guide structure may or may not be removed prior to balloon inflation or infusion. Suitable openings 474 provide for fluid flow into and out of the interior of lumen 470 and balloon 456. Infusion lumen 460 provides for fluid flow out of the catheter at one or more infusion ports 476, which can direct liquid from a proximal reservoir to infusion ports 476 near the distal end of the catheter just proximal to balloon 456. Valve / seal embodiments are discussed further following discussion of FIG.

[0041] With reference to FIG. 18, the proximal fitting 458 comprises two branch conduits 480, 482 and a proximal connector 484. The particular configuration of the proximal fitting 458 may be appropriately selected based on the various options available to provide the described functionality. In the particular embodiment shown in FIG. 18, an infusate reservoir 486 is connected to the branch conduit 480 at connector 488, and a balloon inflation reservoir 490 is connected to the branch conduit 482 at connector 492, such that the guide structure may exit the dual lumen catheter 450 at the proximal connector 484. In an alternative embodiment, the guide structure may exit the dual lumen catheter 450 through the branch conduit 480 and through the connector 492, with the balloon infusion reservoir connected to the proximal connector 484.

[0042] 19, a dual lumen catheter 500 has a similar structure to the dual lumen catheter 450 of FIG. 18, with the general arrangement of the infusion and balloon lumens reversed. Referring to FIG. 19, the dual lumen catheter 500 includes an inner shaft 502, an outer shaft 504, a balloon 506, and a proximal fitting 508. A balloon lumen 510 is formed within the outer shaft 504 around the outside of the inner shaft 502. The inner shaft 502 has a lumen 520 that functions as an infusion lumen and a guide lumen. The inner shaft 502 further includes a valve / seal 522 within the lumen 520 near the distal end of the inner shaft 502 to restrict the flow of liquid beyond the valve / seal 522. In general, the guide structure generally extends the length of the dual lumen catheter 500, extending distally from the end of the catheter through the valve 522, which again restricts the passage of liquid in either direction through the valve. The guide structure may or may not be removed prior to balloon inflation or injection. Suitable openings 524 provide for fluid flow to and from the interior of the balloon lumen 510 and balloon 506, which may be secured around the outside of the inner shaft 502, the outside of the outer shaft 504, or a combination thereof. The lumen 520 provides for fluid flow from the catheter at one or more ports 526, which may direct liquid from a proximal reservoir to an injection port 526 near the distal end of the catheter just proximal to the balloon 506. One or more conduits 528 connect the lumen 520 to the one or more injection ports 526. The conduits may be formed, for example, by small tubes, such as metal tubes, that penetrate the wall to form the desired conduit structure.

[0043] The proximal fitting 508 comprises two branch conduits 530, 532 and a proximal connector 534. The particular configuration of the proximal fitting 508 may be appropriately selected based on the various options available to provide the described functionality. In the particular embodiment shown in FIG. 19, a balloon inflation reservoir 536 is connected to the branch conduit 530 at connector 538, and an infusate reservoir 540 is connected to the branch conduit 532 at connector 542, allowing the guide structure to exit the dual lumen catheter 500 at the proximal connector 534. In an alternative embodiment, the guide structure may exit the dual lumen catheter 500 through the branch conduit 532 and through the connector 542, with an infusion reservoir connected at the proximal connector 534.

[0044] The design of the valve / seal structure can be determined by the intended use of the device. For example, if the device is intended to simply be advanced over the guide structure, a valve structure that provides a seal around the movable wire can provide a desirable function. If the catheter is intended to be advanced over the guide structure and then removed, a valve structure can be used that seals following removal of the wire and provides a seal around the guide once in place. During delivery of the catheter over the guide wire, the valve is open, which can allow blood to leak into the balloon. Corresponding complications associated with blood leaking into the balloon and imaging the balloon are described for valve-less devices with common guidewire and balloon lumens, see US Patent Application Publication No. 2016 / 0144157 to Gulachenski et al., entitled "Reinforced Balloon Catheter," incorporated herein by reference. Thus, valves as described herein can be used to reduce or eliminate such leakage.

[0045] Valves in these catheters that close the guidewire lumen can engage the wire and seal the lumen at the valve. Thus, a guidewire can be pushed through the valve, and if present, the guidewire will hold the valve open. If the guide structure is removed, the valve can close to seal the lumen. The valves can be made from a variety of materials, such as polymers (elastomers, etc.), ceramics, metals, or combinations thereof, with relatively low cost and suitable performance for these applications, but can be formed from elastomers such as polyurethane or polysiloxane. In some embodiments, the valves can have two or three coapted leaflets, and a tri-leaflet valve 550 with leaflets 552 is shown in FIG. 20. Valves for guidewires with two or three leaflets are also described in U.S. Patent No. 6,306,124 to Jones et al., entitled "Microcatheter," which is incorporated herein by reference.

[0046] Other valve / seal designs can be used. Referring to the valve / seal embodiment of Figures 21 and 22, a catheter 560 has a seal 562 formed of a flexible elastomer with a central hole 564 that closes when the guide structure is lost, as shown in Figure 21. As shown in Figure 22, a guide structure 566 can be pushed through the seal 562 to extend through the central hole 564. This type of valve / seal is also discussed in U.S. Patent No. 6,432,091 to Davey, entitled "Valved Over-The-Wire Catheter," which is incorporated herein by reference. A valve design that blocks flow around a sliding guide structure, where the guide structure is not intended to be removed, can be similar to the structure of Figures 20-22, except that the valve cannot completely seal when the guide structure is removed. Such structures are also described in U.S. Patent No. 5,259,839 to Burns, entitled "Balloon Catheter With Guidewire Valve," and U.S. Patent No. 9,174,025 to Mallaby, entitled "Rapid Exchange Catheters Having a Sealed Guidewire Lumen and Methods of Making the Same," both of which are incorporated herein by reference. If it is desired to deliver the guidewire into the patient's body before attaching a profusion catheter over the guidewire, a loading tool can be used to hold the valve open while the guidewire is inserted into the lumen from its distal end. A suitable loading tool can be a slit polymer tubular section that can be inserted over the valve and then peeled off after loading the guidewire.

[0047] Generally, the catheters shown in Figures 1-22 may include one or more marker bands and / or other imageable components to position the balloon and profusion ports distal to the clot. While the structure provides appropriate constraints on the placement of the imageable elements based on achieving desired mechanical performance, generally there is significant design flexibility for the placement of such radiopaque elements, and one of ordinary skill in the art may manage such placement to achieve convenience for the corresponding procedure.

[0048] As used herein, a guidewire or guide structure may refer to any suitable elongate element suitable for guiding the delivery of a therapeutic catheter, such as a wire, a coil, or an integrated guide structure comprising a coil element and an overtube, specific examples of guide structures are described below.

[0049] The catheter components may be formed from one or more biocompatible materials including, for example, stainless steel or alloys, metals such as Nitinol®, or polymers such as polyetheramide block copolymers (PEBAX®), nylon (polyamide), polyolefins, polytetrafluoroethylene, polyesters, polyurethanes, polycarbonates, polysiloxanes (silicones), polycarbonate urethanes (e.g., ChronoFlex AR®), mixtures thereof, or other suitable biocompatible polymers. Radiopacity may be achieved by adding metal markers such as platinum-iridium alloys, tantalum, tungsten, gold, platinum-tungsten alloys, or mixtures thereof, such as in the form of wires or bands, or through radio-pacifiers such as barium sulfate, bismuth trioxide, bismuth subcarbonate, powdered tungsten, powdered tantalum, or the like, or combinations thereof, added to the polymer resin. Generally, different sections of the suction catheter can be formed from different materials than other sections, and the sections of the suction catheter can include multiple materials at different locations and / or at specific locations. In particular, it may be desirable to form the seal components from elastomeric polymers, such as suitable polyurethanes, rubbers, synthetic rubbers, polydimethylsiloxanes, polytetrafluoroethylenes, other elastomers, or combinations thereof. Furthermore, selected sections of the catheter can be formed from materials that introduce the desired stiffness / flexibility to the particular section of the catheter. Similarly, the fittings can be formed from suitable materials, such as one or more metals and / or one or more polymers.

[0050] In some embodiments, the balloon / infusion catheter, microcatheter, guide catheter, suction extension or suitable portion thereof comprises a thermoplastic polymer with embedded metal elements reinforcing the polymer. Suitable polymers include, for example, polyamides, i.e., nylons, polyetheramide block copolymers, polyolefins, combinations thereof, and the like. The wire can be braided, coiled, or otherwise placed over the polymer tube liner with some tension to keep the wire in place over the tube liner. FIG. 23 shows a cutaway portion of a representative reinforced catheter section, where the catheter section 580 has a metal reinforcement 582 embedded in the polymer wall 584. In some embodiments, the suction tip can comprise a braided wire and a metal coil, which provides the desired flexibility and resilience to the element along with mechanical strength from the thin wall. A polymer jacket, such as a heat shrink polymer, can then be placed over the top, or the polymer can be softened to allow for the incorporation of the metal reinforcement. Upon heating to a temperature above the softening or heat shrink temperature of the polymer and then cooling, the wire becomes embedded within the polymer. In suitable embodiments, the liner and jacket can be the same or different materials. Suitable wires include, for example, flat stainless steel wires and the like. Wire diameters can range from about 0.00025 inches (0.00635 mm) to about 0.004 inches (0.1 mm), and in further embodiments, from about 0.0005 inches (0.013 mm) to about 0.003 inches (0.075 mm). Braid picks per inch can be from about 20 to about 250 picks / inch, and in further embodiments, from about 50 to about 150 picks / inch. The coils can be single filament or multifilament coils, for example, having a pitch of about 0.005 inches (0.13 mm) to about 0.1 inches (2.54 mm), and in further embodiments, from about 0.01 inches (0.26 mm) to about 0.050 inches (1.27 mm). A person of ordinary skill in the art will recognize that additional ranges within the explicit below ranges are contemplated and are within the present disclosure. The wire adds additional mechanical strength while maintaining a suitable amount of flexibility.The wire may provide some radiopacity, with the radiopaque band generally providing a darker, more discernible image of the wire, however the image of the wire may provide additional visualization of the catheter during the procedure.

[0051] To reduce the chance of accidental removal of the radiopaque band from the catheter and the chance of the radiopaque band catching on other objects in the vessel, a metal reinforcing wire can be used to cover or encapsulate the radiopaque band, which is then embedded in a polymer. As described in the preceding paragraph, the metal wire can include interwoven wires, coils, combinations thereof, and the like. A polymer jacket can be placed over the metal wire, which correspondingly covers the radiopaque band, and the thermal bond also embeds the radiopaque marker band. Placing a marker band under the metal wire can prevent the band from separating from the catheter in the event of a kinked or crushed wall. If a collapse or kink in the catheter wall occurs, the braided wire over the surface of the band will fold over the marker band to prevent the marker band from separating from the structure.

[0052] Referring to FIG. 24, an example of a procedure for forming a reinforced tubular structure section for a catheter is shown generally. A polymer liner 600 is placed over a mandrel 602. In the second figure that follows, a metal braid 604 is placed over the polymer liner; commercially available braiding equipment can be used for this step. As shown in the third figure that follows, a metal coil 606 is placed over the braided wire 604, and a polymer cover 608 is placed over the coil 606. A heat source 610 can be used to heat the heat shrinkable polymer cover 608 to complete the reinforced catheter section 612, as shown in the fourth figure that follows in FIG.

[0053] Treatment System The use of balloon / infusion catheters described in the preceding sections also includes the use of suction catheters. Generally, a guide catheter is also used, which may or may not be a component of the suction catheter system. For some procedures, additional components may also be used, either simultaneously with the balloon / infusion catheter or sequentially. FIG. 25 shows a schematic of a representative set of devices that may be used in appropriate combination as a system for the performance of the procedures described herein. The components of the system may or may not be packaged together. With reference to FIG. 25, a treatment system 650 includes a balloon / infusion catheter 652, a guide catheter 654, an aspiration catheter or nozzle 656, a guide structure 658, additional treatment structures 660, a rear attachment 662, an infusion fluid source 664, a balloon inflation fluid source 666, and an aspiration source 668. A given treatment system may include some of these components, additional components of the same or different types, or a combination thereof, to meet a particular treatment objective. For embodiments of particular interest, treatment system 650 generally includes at least balloon / infusion catheter 652 and suction catheter or nozzle 656, where the suction nozzle functions with the guide catheter as an aspiration system. Balloon / infusion catheter 652 embodiments are described in detail above. Generally, any of the balloon / infusion catheter embodiments in Figures 1-22 can be used, although some embodiments may or may not be compatible with all ancillary treatment devices, such as fixed wire balloon / infusion catheters that are generally not used with a separate guide structure.

[0054] The guide catheter 654 may simply be a structure that facilitates delivery of the remaining structure into the patient's vasculature, or it may function with a suction nozzle to form a suction system. FIG. 26 shows an embodiment of a guide catheter 670, and an embodiment of a guide catheter adaptor for use with a suction nozzle is described further below. With reference to FIG. 26, the tubular shaft 672 may have an approximately constant diameter along its length, or the guide catheter may have sections with different diameters, generally with a relatively smaller diameter section distal to a relatively larger diameter section. The tubular shaft 672 may have one or more radiopaque marker bands to facilitate positioning of the tubular shaft within the patient's body; FIG. 26 shows a marker band 674 near the distal end of the tubular shaft 672, but alternative locations may be used as desired. The tubular shaft 672 may have a coating on its inner and / or outer surface or portions. The guide catheter may also have a balloon at or near its distal end and a corresponding balloon lumen. The guide catheter 670 can include a hemostasis valve 676 at the proximal end of the shaft 672, and other fittings can be adapted for use in addition to or in place of the hemostasis valve 676, either connected as a unitary structure or connected using suitable connectors. The descriptions of materials, dimensions and construction of the catheters discussed above are equally applicable to the guide catheter.

[0055] A suction catheter, even when used alone, can be an effective component for the removal of cerebral clots. Although a suction catheter can be effective when used alone, when the suction catheter is combined with other elements described herein, the combined treatment system can provide several elements working together to remove the clot. The suction catheter provides a removal force from the proximal side of the clot.

[0056] Various aspiration catheters have been developed to provide improved aspiration in the small, tortuous vessels of the cerebral vasculature. In some embodiments, these aspiration catheters have a narrowed distal tip that can reach into small vessels, but provide a high flow rate out of the vessels due to a larger proximal lumen. These improved designs are described in U.S. Patent No. 9,662,129, entitled "Aspiration Catheters for Thrombus Removal," by Galdonik et al., which is incorporated herein by reference. Referring to FIG. 27, an aspiration catheter 680 for accessing smaller vessels includes a tube 682, a reduced diameter distal segment 684 having a smaller average diameter relative to the average diameter of the tube, an optional curved distal tip 686, a radiopaque marker band 688 that may be at or near the distal tip, whether curved or not, a proximal end 690, an aspiration connection 692, a suction device 694, and a proximal port 696 for inserting a guide structure or other device into the catheter lumen. The suction catheter 680 can optionally have a rapid exchange configuration with a rapid exchange port. The suction connection 692 can include a fitting or the like that provides a sealed connection with the suction device 694, or the suction device 694 can be formed as an integral part of the proximal end 690, such that the suction connection 692 is an integral connection. Suitable suction devices include suction devices capable of delivering a selected amount of suction, such as a syringe, a compression bladder, a pump, such as a peristaltic pump or a piston pump, or the like.

[0057] The distal segment 684 can have an outer diameter of about 25 percent to about 95 percent, in further embodiments about 45 percent to about 90 percent, and in further embodiments about 60 percent to about 85 percent of the average outer diameter of the catheter tube 682. For example, the distal segment 684 can have an outer diameter range of about 0.015 to about 0.120 inches, and the tube 682 can have an outer diameter range of about 0.030 to about 0.150 inches, in other embodiments about 0.040 to about 0.125 inches, and in further embodiments about 0.045 to about 0.120 inches. One of ordinary skill in the art will recognize that additional ranges of dimensions within the explicit ranges above are contemplated and are within the scope of the present disclosure. In optional embodiments, a bent or curved tip can provide improved tracking during delivery into a patient's vasculature by controlling tracking along a guiding structure extending from the tip.

[0058] Aspiration catheters with tapered distal segments approved and commercially available for neurovascular procedures include the MI-AXIS™ (MIVI Neuroscience, Inc.) and the MAX™ catheter (Penumbra). The new design is based on the use of a guide catheter that serves as part of the aspiration lumen with a tapered extension of the aspiration catheter extending from the guide catheter. See U.S. Patent Application Publication No. 2017 / 0143938 by Ogle et al., entitled "Catheter Systems for Applying Effective Suction in Remote Vessels and Thrombectomy Procedures Facilitated by Catheter Systems," which is incorporated herein by reference. FIG. 28 shows an embodiment of these nozzle-type aspiration catheters.

[0059] 28, suction system 700 comprises a suction adapted guide catheter 702 and a suction extension 704. Suction adapted guide catheter 702 comprises a proximal section 706 and a tubular shaft 708. Proximal section 706 is generally suitable for use as a handle as well and generally comprises a proximal fitting 720, a suction port 722 and an optional control wire port 724, along with possibly other additional ports and / or fittings to provide desired functionality and access, where all such ports and fittings may be arranged in a bifurcated or other suitable configuration. Proximal fitting 720 may comprise a suitable hemostatic valve, luer fitting, Tuohy-Borst connector, etc., to provide for entry of the guidewire and / or structures to be delivered over the guidewire and into the guide catheter lumen, such as alternative therapeutic structures and / or embolic protection devices. As shown in FIG. 28, a negative pressure device 726 is shown connected to the suction port 722, and suitable negative pressure devices include, for example, a syringe, a pump such as a peristaltic pump, a piston pump or other suitable pump, an aspirator / venturi, or the like.

[0060] The tubular shaft 708 may have an approximately constant diameter along its length, or the guide catheter may have sections of different diameters, generally with a relatively smaller diameter section distal to a relatively larger diameter section. The tubular shaft 708 may have one or more radiopaque marker bands to facilitate positioning of the tubular shaft within the patient's body; FIG. 28 shows a marker band 728 near the distal end of the tubular shaft 708, but additional and / or alternative locations may be used as desired. A stop 730 is positioned at or near the distal end of the shaft to retain a portion of the suction extension 704 within the lumen of the tubular shaft 708. The tubular shaft 708 may further comprise a seal 532 that allows for reducing or eliminating any flow within the tubular shaft 708 that avoids the suction extension 704. In some embodiments, the seal 732 can be combined with the stop 730, or through design, there can be a tight enough fit between the suction extension 704 and the lumen wall of the tubular shaft 708 such that the seal 732 can be avoided as a separate element.

[0061] The suction extension 704 can include a proximal portion 740, a suction tip 742, a connecting portion 744, an optional engagement element 746, and a control structure 748, such as a control wire. All or a portion of the proximal portion 740 can be configured to remain within the lumen of the guide catheter 702. As shown in FIG. 28, the proximal portion 740 includes a radiopaque marker band 752, although in some embodiments it may not have a marker band and in other embodiments may include multiple marker bands. The suction tip 742 is shown with a radiopaque marker band 754 near the distal tip of the suction tip 742, but again, the suction tip 742 can include multiple radiopaque marker bands if desired. The connecting portion 744 connects the proximal portion 740 and the suction tip 742 and can be a transition portion with a gradual change in diameter or a connector that forms a seal between the proximal portion and the suction tip. An optional engagement element 746 can engage with the stop 730 to establish a distal placement limit of the suction extension 704 relative to the guide catheter 702. In some embodiments, the stop 730 is configured to engage an edge or other limiting structure of the proximal portion 740 such that the engagement element 746 effectively integrates with the proximal portion 740 or the connecting portion 742. The control structure 748 can be a control wire or the like that connects with the proximal portion 740 and extends outside of the catheter, such as through the control wire port 724. The control structure 748 can be used to control the positioning of the proximal portion 740 within the lumen of the tubular shaft 708. The control structure 748 can include a control implement 756, such as a handle, slide, or the like, to which the control wire or other connecting element can be secured to facilitate movement of the control wire. In some embodiments, a gap can be created between the outer surface of the proximal portion 740 and the inner surface of the tubular shaft 708 that is small enough that a separate seal is not required.

[0062] The guide catheter can have an outer diameter of about 5.5 French (1.667 mm diameter) to about 10 French (3.333 mm diameter), in further embodiments about 6 French (1.833 mm diameter) to about 9 French (3 mm diameter), and in some embodiments about 6.25 French (2 mm diameter) to about 8.5 French (2.833 mm diameter). Guide catheter measurements generally refer to the outer diameter, with the inner diameter being twice the wall thickness less than the outer diameter. The length of the guide catheter can be about 30 cm to about 150 cm, in further embodiments about 35 cm to about 130 cm, and in further embodiments about 40 cm to about 120 cm. The length of the suction extension 704 can be about 30 cm to about 150 cm, in further embodiments about 35 cm to about 130 cm, and in further embodiments about 40 cm to about 120 cm. A person of ordinary skill in the art will recognize that additional ranges of dimensions within the above explicit ranges are contemplated and are within the scope of the present disclosure.

[0063] Guidewire, unless otherwise indicated, may refer herein to a conventional guidewire or a guide structure that may have more structural features relative to a conventional guidewire. Guidewires for neurovascular applications are commercially available. These include TRANSEND® (Stryker) with a distal outer diameter (OD) of 0.014 inches (0.36 mm) and a proximal outer diameter of 0.0155 inches (0.40 mm), SYNCHRO® (Stryker) with various diameters, CHIKAI™ (Asahi Intecc) with a 0.36 mm diameter, and HEADLINER® (MicroVention / Turumo) with various diameters available. Guidewires for cerebral vessels with hyperbolic core wire grinds are described in U.S. Patent Application Publication No. 2016 / 0199620 by Pokorney et al., entitled “Medical Guidewires for Tortuous Vessels” (hereinafter the '620 application), which is incorporated herein by reference. These guidewires are suitable for the appropriate procedures described herein.

[0064] The guide structure 658 can have a diameter of about 0.005 inches to about 0.04 inches, in further embodiments about 0.007 inches to about 0.030 inches, in further embodiments about 0.0075 inches to about 0.020 inches, and in other embodiments about 0.008 inches to about 0.017 inches over the majority of its length apart from any distal structures, with a standard guidewire outer diameter being about 0.014 inches. The length of the guide structure 658 can generally be selected for a particular procedure design. For example, to enter the vasculature of the femoral artery to navigate to the cerebral artery, the guide structure 658 generally has a length of about 190 cm (63 inches) to about 300 cm (106 inches), although shorter lengths, such as 30 cm to 190 cm, may be suitable for other entry vessels. One of ordinary skill in the art will understand that additional ranges within the explicit ranges for diameter are contemplated and are within the scope of the present disclosure.

[0065] Generally, the guide structure 658 can be formed from one or more of a variety of materials, such as polymers, metals, and combinations thereof, although metals can provide a favorable balance of strength, flexibility, and deliverability to a target location within the cerebral vasculature. Suitable materials are generally biocompatible in that they are non-toxic, non-carcinogenic, hemocompatible, and do not cause hemolysis or significant immunological reactions. Suitable biocompatible materials include, for example, titanium, cobalt, stainless steel, nickel, iron alloys, cobalt alloys such as Elgiloy®, cobalt-chromium-nickel alloy, MP35N, nickel-cobalt-chromium-molybdenum alloy, and Nitinol®, a nickel-titanium alloy. Some of these metals are suitable for use as shape memory metals, where a particular shape is designed into the metal element upon formation, and the element can be distorted into another shape for delivery and later regain its pre-designed shape. Shape memory metals can be used, for example, for self-actuation with respect to fiber-based filters, referenced below. Suitable polymers for the guide structure or portions thereof include, for example, polyetheramide block copolymers (PEBAX®), nylon (polyamide), polyolefin, polytetrafluoroethylene, polyester, polyurethane, polycarbonate, polysiloxane (silicone), polycarbonate urethane (e.g., ChronoFlex AR®), mixtures thereof, or other suitable biocompatible polymers.

[0066] The guide structure can generally have a guidewire structure over most of its length, but can optionally further include other features not directly related to guidewire mechanical performance. For example, the '620 application describes a guide structure with a core wire that can be stretched within a vessel to effectively increase the wire length available for device delivery. In some embodiments, the guide structure can include a filter or embolic protection device generally near its distal end. Fiber-based filter devices have been found to be effective for delivery with the guide structure. Fiber-based filter devices can include polymer fibers that can be mixed with fibers of a biocompatible metal. Suitable polymers for the polymeric fibers include, for example, polyamides (e.g., nylon), polyesters (e.g., polyethylene terephthalate), polyacetals / polyketals, polyimides, polystyrenes, polyacrylates, vinyl polymers (e.g., polyethylene, polytetrafluoroethylene, polypropylene, and polyvinyl chloride), polycarbonates, polyurethanes, polydimethylsiloxanes, cellulose acetate, polymethyl methacrylate, polyether ether ketone (PEEK), ethylene vinyl acetate, polysulfones, nitrocellulose, similar copolymers, and mixtures thereof.

[0067] Embolic protection devices have been developed that have small filter lateral extents suitable for use in the medical system described herein and are designed for suitable manipulation to facilitate intravascular delivery.See, for example, U.S. Patent No. 7,879,062 B2 to Galdonik et al., entitled "Fiber Based Embolic Protection Device," and U.S. Patent No. 8,092,483 B2 to Galdonik et al., entitled "Steerable Device Having a Corewire Within a Tube and Combination with a Medical Device," both of which are incorporated herein by reference.The FiberNet® embolic protection device, based on the technology of these patents, is sold by Medtronic Inc.These fiber-based embolic protection devices include a guide structure with a core wire that allows the deployment of the embolic protection device using an actuator at the proximal end outside the patient's body.

[0068] Additional fiber-based filter devices specifically designed for delivery into tortuous vessels, such as cerebral arteries, are described in U.S. Pat. No. 8,814,892 B2 by Galdonik et al. (hereinafter the '892 patent), entitled "Embolectomy Devices and Method of Treatment of Acute Ischemic Stroke Condition," which is incorporated herein by reference. Fiber-based filters generally include polymeric fibers that provide a low-abrasion surface against the vessel wall, but may also include some metal fibers / wires that add mechanical strength to the filter, which may be incorporated into the structure to avoid abrasion to the vessel wall. The '892 patent describes the use of the filter device as a clot-engaging instrument for use with an aspiration catheter. The '892 patent also contemplates the use of complementary structures to facilitate engagement with the clot. Additional embodiments of fiber-based filter devices are described in the '061 application. These filters may be deployed using microcatheters or other structures.

[0069] As will be further described below, the procedure may use a guidewire to facilitate access to the desired location within the vessel, which may be removed at any point during the process. As mentioned above, the balloon / dilation catheter may not involve a wire, may have an integral fixed wire, or may have a design that allows it to be advanced over a guidewire. Catheter designs that allow it to be advanced over a guidewire (see FIG. 8, FIG. 16 (some embodiments), FIG. 18, and FIG. 22) may be used with guide structures that have embolic protection structures at their distal ends.

[0070] The use of an additional treatment structure 660 or multiple treatment structures 660 is also contemplated as an option in the procedures described herein. Suitable devices as additional treatment structures 660 can, for example, apply mechanical force to the clot to facilitate removal of the clot. With respect to additional treatment structures 660, suitable devices include, for example, angioplasty balloons, stent delivery devices, atherectomy devices such as stent retrievers, and the like. Stents can be, for example, balloon-expandable, self-expandable, or expandable using any other suitable mechanism. Balloon-expandable stents can be crimped onto a balloon for delivery. Some balloon-stent configurations are further described in U.S. Patent Nos. 6,106,530, entitled "Stent Delivery Device," 6,364,894, entitled "Method of Making an Angioplasty Balloon Catheter," and 6,156,005, entitled "Ballon[sic] Catheter For Stent Implantation," each of which is incorporated herein by reference. Self-expanding stents are further described in U.S. Patent Nos. 8,764,813 to Jantzen et al., entitled "Gradually Self-Expanding Stem," and 8,419,786 to Cottone, Jr. et al., entitled "Self-Expanding Stent," both of which are incorporated herein by reference. Stent retrievers are described, for example, in U.S. Patent No. 8,795,305 to Martin et al., entitled "Retrieval systems and methods of use thereof," which is incorporated herein by reference. Stent retrievers having a flexible frame and polymer covering to provide a gentler interface with the vessel wall are described in detail in the '061 application. Stent retrievers such as those described in the '061 application can be used and removed prior to delivery of the balloon / infusion catheter.

[0071] As mentioned above, microcatheters can be used as components of balloon / infusion systems (see FIG. 1), and microcatheters can be used for other purposes during a procedure. Microcatheters are designed to allow access to small blood vessels, such as cerebral blood vessels, and cerebral microcatheters are commercially available, for example, Prowler Select™ (Cordis Neurovascular Inc.) and Spinnaker Elite™ (Boston Scientific Co.). Of course, the term microcatheter can encompass a wide range of devices, and this discussion will focus on catheters useful for the procedures described herein. In some embodiments, the microcatheter can include a distal section that is thinner than the proximal section. However, in further embodiments, the microcatheter can have an approximately constant diameter along its length to facilitate the delivery of other devices over the microcatheter. The narrow distal diameter allows the catheter to navigate the tortuous blood vessels of the brain. The distal section can be flexible enough to navigate the blood vessels, yet elastic enough to resist kinking. The microcatheter comprises at least one lumen. The microcatheter can then be used to deliver (or provide) other therapeutic devices, aspiration flow, therapeutic agents, and the like, or combinations thereof. The microcatheter can be of a selected size, but in some embodiments can have a distal outer diameter of about 1.0 French to about 3.5 French, and in further embodiments, about 1.5 French to about 3 French, and a length of about 30 cm to about 200 cm, and in further embodiments, about 45 cm to about 150 cm. A person of ordinary skill in the art will recognize that additional size ranges within the explicit ranges above are contemplated and are within the scope of the present disclosure.

[0072] The rear fitting 662 can have a suitable structure, which may be integral with the catheter or a separate component with appropriate connectors, for assembly and operation of the treatment system 650. For example, various conventional connectors can be associated with the fitting to facilitate connection of devices, suitable connectors include, for example, tuohy-borst connectors, luer connectors, and the like. As described above, the guide catheter generally includes one hemostatic valve, but the rear fitting 662 can include one or more additional hemostatic valves, if suitable for use of the various components as a system. Hemostatic valves allow devices to pass through the catheter with little or no bleeding and are commercially available. The rear fitting 662 can include a manifold structure with optional branches to provide desired connectors or connections for additional fittings. For example, the rear fitting 662 can include one or more Y-branches or alternative branch structures, which can provide connectors for, for example, an infusion fluid source 664, a balloon inflation fluid source 666, a suction source 668, or combinations thereof.

[0073] The infusion fluid source 664 and the balloon inflation fluid source 666 can be separate structures or can be combined as a single structure where an intraluminal balloon / inflation catheter uses a common lumen for both balloon inflation and infusion. Suitable structures for the infusion fluid source 664 and the balloon inflation fluid source 666 can include a reservoir of fluid and a fluid delivery structure. The fluid delivery structure can be manual or mechanical, such as a syringe, a compression bladder, a pump such as a peristaltic or piston pump. The balloon inflation fluid source 666 (or a combined fluid source) is generally also reversible to remove fluid when it is desired to deflate the balloon.

[0074] The infusion fluid reservoir generally contains a biocompatible liquid, such as sterile buffered saline, the patient's own blood or a compatible blood, such as blood of the appropriate type, in a volume selected for the procedure, although the balloon inflation fluid source can in principle contain a wider range of fluids if not used for infusion and maintained from entering the patient's body. The infusion fluid can further contain drugs, such as thrombolytic drugs, antispasmodics, or combinations thereof. As fluid is aspirated from the blood vessel, generally a relatively large amount of drug can be delivered to be available in the treatment area for a short period of time. Suitable thrombolytic drugs include, for example, tPA (tissue plasminogen activator). The infusion reservoir can have a volume of about 0.1 cc (cubic centimeter) to about 50 cc, in further embodiments, about 0.2 cc to about 35 cc, and in further embodiments, about 0.25 cc to about 25 cc. One of skill in the art will appreciate that additional ranges of volumes within the above explicit ranges are contemplated and are within the scope of the present disclosure. The suction source 668 can be any suitable negative pressure device. Suitable negative pressure devices include, for example, syringes, pumps such as peristaltic pumps, piston pumps or other suitable pumps, aspirators / venturis, etc. Suitable pumps are available from Allied Healthcare Products, Inc. and distributed by Mivi Neuroscience, Inc.

[0075] treatment The procedures described herein are generally designed to provide clot removal based on aspiration and injection. The resulting hydraulic and hydrodynamic forces from the resulting flow can provide an effective process for clot removal with the goal of less trauma to the vessel wall and surrounding tissue. The entire procedure allows access to a blood vessel, e.g., a cerebral blood vessel, beyond the clot. A balloon / infusion catheter is positioned such that the balloon and injection port are located distal to the clot, and an aspiration catheter is positioned such that the aspiration port is proximal to the clot. Infusion and aspiration are then applied simultaneously to establish flow, but not necessarily throughout the entire time each flow is applied. The resulting fluid flow encourages the movement of the clot, or a portion thereof, to and / or into the aspiration catheter. The following discussion focuses on procedures to remove clots in cerebral arteries that cause acute ischemic stroke events, and one skilled in the art can adapt this discussion to other arteries or other blood vessels within a patient's body based on the discussion herein.

[0076] Referring to FIG. 29, a human patient 780 is shown with an appropriate portion of a treatment system 782 inserted into the patient's femoral artery 784, where the components are guided up the descending aorta 786 and around the aortic arch to the ascending aorta 788, where they are guided into the carotid artery 790 (left or right) before reaching the heart. The distal end of the components is then guided through the patient's neck into the internal carotid artery and then into the cerebral arteries that form the neurovasculature. While this may be the desired approach to the cerebral arteries, alternative access locations include the arm 792 or neck 794. Radiopaque markers are generally used to aid in the placement of various devices, including placement of balloons and injection ports distal to the clot using real-time imaging.

[0077] FIG. 30 shows a schematic of the basic arrangement for performing the procedure. As mentioned above, the basic concept is to generate hydraulic force between an expanded occlusion balloon and an aspiration catheter to dislodge the clot. As shown in FIG. 8, the treatment system is positioned in a patient's blood vessel 800, e.g., an artery. A clot 802 resides within the blood vessel 800. A balloon / infusion catheter 804 is positioned within the blood vessel 800 such that the balloon 806 is inflated distal to the clot 802 and an infusion port 808 is positioned between the clot 802 and the balloon 806. An aspiration catheter 810 is positioned over the balloon / infusion catheter 804 such that an aspiration opening 812 is proximal to the clot 802 within the blood vessel 800. Flow arrows 814 indicate flow resulting from aspiration, and infusion fluid 816 is shown shaded as it is infused into the blood vessel 800 between the balloon 806 and the clot 802. Hydraulic force on the clot 802 in a distal to proximal direction is generated by infusion fluid 816 distal to the clot, and suction is applied by an aspiration catheter proximal to the clot 802.

[0078] Preliminary preparation for a percutaneous procedure may include access into the arterial system along with placement of a hemostatic fitting and other appropriate components that provide access into the patient's body. In some embodiments, access is obtained into the femoral artery, although other access locations may be used. In the case of access through the femoral artery, the device may include a guide that navigates upstream into the artery to an entrance into the common carotid artery, from which access may be obtained into the cerebral vasculature. In some embodiments, to facilitate subsequent steps of the procedure, a guide catheter is positioned such that its distal end is within a carotid artery, such as the internal carotid artery. The guide catheter may have a balloon, and may or may not be used for suction, whether the guide catheter has an occlusion balloon or not.

[0079] A common feature of the procedures described herein involves gaining access to a cerebral artery distal to the clot, generally performed with a guide structure, e.g., a guidewire. The distal position to the clot is generally maintained until the clot is at least partially removed. Once the guide structure has established its position, components can be delivered over the guide structure. At some point, a balloon / infusion catheter is delivered to position the balloon distal to the clot and the infusion port between the balloon and the clot. The delivery process may or may not involve a microcatheter, and the guidewire may or may not be removed prior to placement of the balloon / infusion catheter. If the guidewire is removed prior to placement of the balloon / infusion catheter, a microcatheter is generally used to maintain the distal position to the clot. Also, the guide catheter may be used for aspiration, but an aspiration catheter is placed prior to initiation of fluid pressure. If the balloon / infusion catheter can be advanced over the guide structure, a wire-based therapeutic device can be delivered through the microcatheter prior to delivery of the balloon / infusion catheter. Fluid flow is used to remove the clot or portions thereof from the blood vessel. Reasonable procedures designed to avoid release of emboli may be used to remove components of the treatment system. This sequence of steps provides an overview of the procedure given practical implementation, but reasonable variations in the sequence of steps may be used if consistent with the overall procedure. Thus, appropriate steps may be performed in different orders, and some steps may be performed in sub-steps that may be interspersed among portions of other steps. Also, repositioning of various components may be performed throughout the procedure as necessary and according to the needs of the user.

[0080] In some embodiments, to perform a procedure, a guidewire is generally positioned with its distal end extending beyond the clot following insertion through or beyond the clot. FIG. 31 shows a neurovascular artery containing a clot and a guidewire positioned within the artery. The guidewire can then be used to guide delivery of additional components for the procedure. With reference to FIG. 31, a guide catheter 830 can be positioned within a carotid artery 832. A guidewire 834 is guided beyond the carotid artery 832 into a cerebral artery 836 with its distal tip 838 positioned beyond the clot 840. A simplified vascular pathway from the carotid artery 832 to an upstream cerebral artery 842 that branches into the cerebral artery 836 is shown in the figure by dashed lines to note portions of the pathway not shown to simplify the drawing. This step is generally important with respect to accessing a desired location distal to the clot, which location distal to the clot is generally maintained until thrombus from the clot migrates to a more proximal location or is removed from the patient's body.

[0081] The next step may depend on whether the balloon / infusion catheter can be advanced over the guide structure. This next figure focuses on an embodiment of a balloon / infusion catheter (having one or more lumens) that is not designed to be advanced over a guide structure, with or without a fixed wire, but a balloon / infusion catheter that can be delivered over a guide structure without being advanced over it can be used, assuming that an appropriate seal can block flow into the catheter lumen in the absence of a guide structure. Following this discussion, a possible modification of the procedure will be considered if the balloon / infusion catheter is advanced over a guide structure during the procedure. Referring to FIG. 32, a microcatheter 848 is positioned over the guidewire 834 so that its distal tip is over the clot 840. Once the microcatheter 848 is in place, the guidewire 834 can be removed while maintaining distal access to the clot with the microcatheter.

[0082] Either before or after the guidewire 834 is removed, the aspiration catheter 860 can be positioned so that its distal tip 862 enters the cerebral vasculature 836, as shown in FIG. 33. Depending on the details of the vasculature and the aspiration catheter design, the aspiration catheter distal tip can be closer or further away from the clot 840, and the aspiration catheter can be in any suitable location within the upstream cerebral artery 842. From the above discussion, it can be understood that references to an aspiration catheter in the context of a procedure can also include an aspiration nozzle that is part of the aspiration system, and such alternative uses of aspiration components are contemplated for all of the embodiments in this section relating to procedures. The medical professional performing the procedure can adjust the procedure accordingly based on the position of the aspiration catheter.

[0083] 33, following removal of the guidewire 834, a balloon / infusion catheter 864 is delivered through the microcatheter 848 to position a balloon 866 and an infusion port 868 beyond the clot 840. The order of delivery of the aspiration catheter 860 and the balloon / infusion catheter 864 can generally be selected as desired. With reference to FIG. 34, the balloon 866 is inflated to block flow in either direction past the balloon.

[0084] Aspiration and infusion are generally initiated following inflation of the balloon 866. Also, aspiration and infusion can be initiated approximately simultaneously or sequentially at planned time intervals, and even if planned to be appropriately simultaneous, the processes are generally initiated separately so that a slight delay is generally provided from the time of starting the processes. In practice, medical professionals can develop techniques according to personal preferences regarding the order of balloon inflation, initiation of suction, and initiation of infusion. For example, a professional may wish to initiate suction, then inflate the balloon, and then inject liquid. In general, any reasonable process order can be used based on the liberation of thrombus from the clot, with appropriate attention to avoiding downstream embolic flow in the vessel.

[0085] Referring to FIG. 35, aspiration is indicated by flow arrows into the aspiration catheter 860 near the aspiration opening, and flow arrows near the injection port 868 indicate the injection of infusate into the vessel. Due to the closure effect of the clot, the injection of liquid initially tends to increase the pressure between the clot and the balloon. The increased pressure tends to increase the vessel diameter accordingly if the vessel wall has some elasticity. The injection pressure and liquid volume can be controlled to avoid damage to the result. The amount of liquid delivery by injection can be optionally changed as the clot is dislodged, allowing the liquid to flow more quickly into the aspiration catheter. Nevertheless, the fluid pressure established by aspiration from a proximal location and injection from a distal location established a fluid force moving in a distal to proximal direction.

[0086] 35, hydraulic forces in the cerebral vessel 836 cause the thrombus 870 from the clot 840 to move proximally. As the thrombus continues to move, the trapped thrombus is removed by the aspiration catheter 860 and / or the trapped thrombus 872 is at the opening into the aspiration catheter 860, as shown in FIG. 36. Depending on the size of the clot and the stiffness of the clot material, the clot may or may not enter completely into the lumen of the aspiration catheter. The thrombus may break apart during the removal process, with some of the thrombus from the clot 840 being removed through the aspiration catheter 860, some of the thrombus being captured at the opening of the aspiration catheter 860, or generally any amount to the entire continuum of the thrombus being removed by aspiration, or all of the thrombus being collected at the top of the aspiration catheter 860. If the aspiration flow is reduced due to blockage or partial blockage of the aspiration catheter by the clot, the infusion flow may be reduced or turned off.

[0087] Following adequate capture of the thrombus, the balloon 866 may be partially deflated or nearly fully deflated and then removed from the vessel. With reference to FIG. 37, the balloon 866 has been partially deflated and removal from the cerebral artery 836 has commenced. The microcatheter 848 may be removed simultaneously with the balloon / infusion catheter 864 or separately before or after the balloon is essentially fully deflated. In some embodiments, following delivery of the balloon / infusion catheter 864, the microcatheter 848 may be moved at least partially to a more proximal position prior to removal of the clot 840 so as to slightly increase the volume of the aspiration lumen between the inner wall of the aspiration catheter 860 and the device passing within the aspiration catheter 860. As shown in FIG. 37, the microcatheter 848 is removed simultaneously with the balloon / infusion catheter 864.

[0088] Suction may or may not be maintained at the same pressure or reduced pressure or combinations thereof at different times during the device removal process or separate parts thereof. Infusion is generally stopped before deflating the balloon 866. The suction catheter 860 may be removed simultaneously with the balloon / infusion catheter 864 or following removal of the balloon / infusion catheter 864. In some embodiments, the suction catheter 860 is maintained in place until the balloon 866 is withdrawn near the opening into the suction catheter 860, after which the catheters 860, 864 are removed together. Generally, the selected order of removing the suction catheter 860 and the balloon / infusion catheter 864 may be selected in a variety of reasonable orders and variations thereof, with some consideration that a medical professional may develop preferences based on their own experience and further clinical studies may suggest certain nuances of the procedure. The order of removal of the components may be selected to promote removal of the thrombus with low risk of embolism from the thrombus. Finally, all of the devices of the system are removed from the patient's body and the patient's entry points are closed.

[0089] Because the balloon / infusion catheter can be advanced over the guidewire, various additional options for the procedure are available. In such embodiments, a microcatheter may not be used since it is not necessary to maintain access to a location distal to the clot. Nevertheless, an option is to further use a microcatheter to facilitate delivery of the balloon / infusion catheter. Such an embodiment is shown in FIG. 38, although an embodiment without a microcatheter would appear similar, only without the microcatheter 848. With reference to FIG. 38, the vessel, clot, and auxiliary devices are shown to be the same as in FIGS. 32-37, but the balloon / infusion catheter 880 is advanced over a guide structure 882. With reference to FIG. 38 and the inset close-up, the balloon / infusion catheter 880 includes a balloon 884, an infusion port 886, and a valve / seal 888. Assuming the valve / seal 888 can provide adequate closure, in some embodiments, following placement of the balloon / infusion catheter 880, the guide structure 882 can be removed. Once the balloon / dilatation catheter 880 is in place, the procedure can continue as described in connection with Figures 34-37, except that if a microcatheter is not being used, removal and suitable adjustment of the guide structure 882 is appropriately considered. The guide structure 882 can be removed simultaneously with the balloon / infusion catheter 880, or earlier in the procedure if leakage of blood into the balloon / infusion catheter 880 is not occurring significantly or is not an issue at that particular stage of the procedure, such as after the balloon 884 is deflated.

[0090] Further embodiments of the procedure may be considered where the balloon / dilation catheter can be advanced over a separate guide structure. Specifically, the original guide wire may be replaced with an alternative treatment structure, such as a filter attached to the guide structure. In these embodiments, a microcatheter is used to maintain access to a location distal to the clot at least until placement of a treatment device, and a distal location is maintained relative to the clot. The steps in the procedures of Figs. 31 and 32 may be the same. Once the microcatheter 848 is in place as shown in Fig. 32, the guide wire 834 may be removed and replaced with device 900, which may be a guide structure with a filter or alternative treatment structure. For illustrative purposes, structure 900 is described and shown in connection with Fig. 39 as a guide structure with a filter 902 near its distal end. As discussed above, the filter 902 may be deployed by a proximal actuator using a core wire, self-actuation upon release from the microcatheter, deployment with an alternative structure as a microcatheter or actuation instrument, or a combination thereof. In some embodiments, the filter 902 is deployed prior to delivery of the balloon / infusion catheter, but depending on the actuation mechanism, the filter 902 can be deployed following delivery of the balloon / infusion catheter or using the balloon / infusion catheter itself as the actuation tool for the filter.

[0091] Referring to Figure 40, a cerebral artery 836 is shown with a filter 902 deployed and a balloon / infusion catheter 904 in place. The balloon / infusion catheter 904 includes a balloon 906, an infusion port 908, and a valve / seal 910 that blocks flow into or out of the lumen of the balloon / infusion catheter 904. See the enlarged view of the inset in Figure 40. Delivery of the suction catheter 860 was discussed above in connection with Figure 33, and these comments generally also apply in connection with Figures 39-42. In Figure 39, the suction catheter 860 is delivered earlier in the process with respect to Figure 33, reflecting options available in the procedure.

[0092] With reference to FIG. 41, the balloon 906 is inflated, aspiration is in progress as indicated by the flow arrows near the opening into the aspiration catheter 860, and infusion is occurring as indicated by the flow arrows near the infusion port 908. The resulting hydraulic force causes the proximal displacement of the thrombus 912 from the clot 840. The fluid force can generally be applied at least until the thrombus is removed through the aspiration catheter 860, or the thrombus is fixed as a trapped thrombus 914 at the opening of the aspiration catheter 860, as shown in FIG. 42, or a combination of these effects. As shown in FIG. 42, the balloon is then partially or nearly completely deflated for removal from the patient's body. In the case of a polymer fiber-based filter 902, the filter 902 can be left deployed during removal to capture emboli in the distal flow that are at risk of forming. As shown in FIG. 43, the sweep of the filter 902 in the cerebral artery 836 can also collect loosened thrombus that was not carried away by the flow. As shown in Figure 43, the microcatheter 848 and balloon / infusion catheter 904 are removed simultaneously with the treatment device 900 and filter 902. As noted above, the order of device removal is generally not important within common sense, and in these embodiments, it may be advantageous to place the filter 902 adjacent the trapped thrombus 914 and then remove the filter 902 with the aspiration catheter 860. Eventually, all of the devices are removed from the patient's body and the access site is sealed. Procedures using aspiration and fiber-based filters without infusion of liquid are also described in the '061 application.

[0093] FIG. 44 illustrates an embodiment of a treatment system having a guide catheter 930 with an occlusion balloon 932. The distal end of the guide catheter 930 is located in the internal carotid artery 934, while the distal end can be placed in the common carotid artery. As shown in FIG. 44, a balloon / infusion catheter 940 is positioned such that the inflated balloon 942 and infusion port 944 are positioned distal to a clot 946 in a cerebral artery 948. When the balloon 932 is inflated to occlude the carotid artery 934, flow is blocked beyond the balloon, thereby reducing pressure on the clot along with flow against suction in the vicinity of the clot 946. As shown in FIGS. 31-43, suction can be applied through the guide catheter in addition to or instead of applying suction through a separate suction catheter.

[0094] The above embodiments are intended to be illustrative and not limiting. Further embodiments are within the scope of the claims. Moreover, although the present invention has been described with respect to specific embodiments, those skilled in the art will understand that changes in form and detail may be made without departing from the spirit and scope of the present invention. Any incorporation by reference of the above-mentioned documents is limited to not incorporation of any subject matter contrary to the explicit disclosure herein. Unless otherwise expressly indicated, and as suggested in the discussion, to the extent that a given structure, configuration and / or process is described with components, elements, ingredients or other parts, the disclosure of the present specification should be understood to encompass embodiments that comprise a given embodiment, a given component, element, ingredient, other part, or combination thereof, as well as embodiments that essentially consist of such a given component, ingredient or other part, or combination thereof, which may include additional features that do not change the basic nature of the subject matter.

Claims

1. A balloon / infusion catheter, A tubular shaft having a central lumen and a distal end, Proximal mounting device, A balloon having a proximal end and an interior, wherein the balloon is attached to or near the distal end of a tubular shaft, the interior of the balloon is in fluid communication with the central lumen, the tubular shaft includes one or more injection ports, one or more of the injection ports are located on the proximal side within about 5 centimeters from the proximal side of the balloon, and the central lumen is sealed on the distal side of the balloon, the balloon and Polymer valve and A wire extending through the central lumen, Equipped with, The polymer valve has an elastic cover attached to one end of the tubular shaft along the outer circumference of the tubular shaft, and controls the flow rate from one or more injection ports. The injection port is in fluid communication with the central lumen, or, if a second lumen is provided, it is in fluid communication with the second lumen, which is concentric with the central lumen and terminates proximal to the sealed position of the central lumen. The wire is sealed inside the central lumen, or the wire extends from inside the central lumen in the sealing valve. Balloon / infusion catheter.

2. The wire is sealed inside the central lumen. The balloon / infusion catheter according to claim 1.

3. The wire extends from inside the central lumen in the sealing valve. The balloon / infusion catheter according to claim 1.

4. The wire extends over most of the length of the tubular shaft, The wire has a distal end fixed to the distal end of the tubular shaft or near the distal end, The balloon / infusion catheter has a single lumen which is the central lumen, The balloon / infusion catheter according to claim 1.

5. The balloon / infusion catheter has a single lumen which is the central lumen, Within the central lumen, a valve is positioned near the distal end. The valve is configured to seal the central lumen when the wire is removed, and to prevent flow into or out of the central lumen when the wire extends through the valve. The balloon / infusion catheter according to claim 1.

6. The wire extends over most of the length of the tubular shaft, The wire has a distal end fixed to or near the distal end of the tubular shaft. The balloon / infusion catheter has a second lumen, The balloon / infusion catheter according to claim 1.

7. The balloon / infusion catheter has a second lumen, The central lumen has a valve configured to provide a seal around the wire, and the valve is further configured to seal the central lumen when the wire is removed. The balloon / infusion catheter according to claim 1.

8. The second lumen is provided with a connector at its proximal end. The balloon / infusion catheter according to claim 6 or 7.

9. The aforementioned connector is in fluid communication with the fluid source. The balloon / infusion catheter according to claim 8.

10. The second lumen is in fluid communication with one or more of the injection ports. The balloon / infusion catheter according to claim 9.

11. A treatment system for removing blood clots from a patient's blood vessels, The balloon / infusion catheter according to any one of claims 1 to 10 and the suction catheter are provided, The balloon / infusion catheter is configured such that, before injecting the fluid, the balloon can be deployed distal to the blood clot to close the blood vessel. The suction catheter is configured to generate fluid pressure distal to the blood clot by injecting fluid from the balloon / infusion catheter between the blood clot and the closure element through an infusion port located only distal to the blood clot, thereby providing a first high pressure distal to the blood clot. Simultaneously, it provides a second low pressure proximal to the blood clot by aspirating fluid with the suction catheter proximal to the blood clot, thereby pushing the blood clot from distal to proximal due to the fluid pressure. The aforementioned liquid pressure is applied to the blood clot without mechanically crushing the blood clot beforehand. Treatment system.

12. The suction catheter is configured to be delivered via the balloon / infusion catheter. The treatment system according to claim 11.

13. The treatment system according to claim 11 or 12, wherein the blood vessel is a cerebral artery.

14. The treatment system according to claim 13, wherein the distal end of the suction catheter can be positioned within the cerebral artery.

15. The suction catheter includes a proximal portion provided with a suction port connected to a negative pressure device. The treatment system according to claim 14.

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