US20050124973A1 - Apparatus and methods for treating stroke and controlling cerebral flow characteristics - Google Patents

Abstract

Apparatus and methods for treatment of stroke are provided. In a preferred embodiment, the present invention disposes at least one catheter having a distal occlusive member in either the common carotid artery (CCA) or both the vertebral artery (VA) and the CCA on the hemisphere of the cerebral occlusion. Blood flow in the opposing carotid and/or vertebral arteries may be inhibited. Retrograde or antegrade flow may be provided through either catheter independently to effectively control cerebral flow characteristics. Under such controlled flow conditions, a thrombectomy device may be used to treat the occlusion, and any emboli generated are directed into the catheter(s).

Description

RELATED APPLICATIONS
• The present application is a divisional of copending U.S. patent application Ser. No. 09/972,225, filed Oct. 4, 2001.
FIELD OF THE INVENTION
• The present invention relates to improved apparatus and methods for treatment of stroke. More specifically, the apparatus and methods of the present invention are directed to treating stroke by controlling cerebral blood flow and removing thrombi and/or emboli.
BACKGROUND OF THE INVENTION
• Cerebral occlusions that lead to stroke require swift and effective therapy to reduce morbidity and mortality rates associated with the disease. Many current technologies for treating stroke are inadequate because emboli generated during the procedure may travel downstream from the original occlusion and cause ischemia. There is currently a need for a stroke treatment system that provides a swift and efficient treatment for occlusions while simultaneously controlling cerebral flow characteristics.
• In the initial stages of stroke, a CT scan or MRI may be used to diagnose the cerebral occlusion, which commonly occurs in the middle cerebral arteries. Many current technologies position a catheter proximal to the occlusion, then deliver clot dissolving drugs to treat the lesion. A drawback associated with such technology is that delivering drugs may require a period of up to six hours to adequately treat the occlusion. Another drawback associated with lytic agents (i.e., clot dissolving agents) is that they often facilitate bleeding.
• When removing thrombus using mechanical embolectomy devices, it is beneficial to engage the thrombus and remove it as cleanly as possible, to reduce the amount of emboli that are liberated. However, in the event that emboli are generated during mechanical disruption of the thrombus, it is imperative that they be subsequently removed from the vasculature.
• Many current drug delivery and mechanical treatment methods are performed under antegrade flow conditions. Such treatment methods do not attempt to manipulate flow characteristics in the cerebral vasculature, e.g, the Circle of Willis and communicating vessels, such that emboli may be removed. Accordingly, there remains a need to provide effective thrombus and emboli removal from the cerebral vasculature while simultaneously controlling flow within that vasculature.
• U.S. Pat. No. 6,161,547 to Barbut (Barbut '547) describes a technique for enhancing flow in the cerebral vasculature in treating patients with acute stroke or other cerebrovascular disease. The technique involves: (1) positioning a first tubular member in a vascular location suitable for receiving antegrade blood flow; (2) positioning a second tubular member in a contralateral artery of the occlusion (e.g., for an occlusion located in the left common carotid artery the second tubular member is placed in the right common carotid artery); and coupling the first tubular member to the second tubular member using a pump and filter.
• The first tubular member receives antegrade blood flow and channels the blood to the pump and filter, where the blood then is reperfused via the second tubular member into the contralateral artery, thus increasing blood flow to the opposing hemisphere of the brain. The first and second tubular members may include balloons disposed adjacent to their distal ends.
• The techniques described in the foregoing patent have several drawbacks. For example, if the first balloon of the first tubular member is deployed in the left common carotid artery, as shown inFIG. 7C, aspiration of blood from the vessel between the balloon and the occlusion may cause the vessel to collapse. On the other hand, if the balloon is not deployed, failure to stabilize the distal tip may result in damage to the vessel walls. In addition, failure to occlude the vessel may permit antegrade blood flow to diverted into that apparatus, rather than blood distal to the first tubular member.
• The Barbut '547 patent further discloses that inflating the balloon of the second tubular member may assist in controlling the flow to the contralateral artery or provide more efficient administration of pharmacotherapy to the cerebral tissues. However, when that balloon is deployed, the contralateral artery may be starved of sufficient flow, since the only other flow in that artery is that aspirated through the first tubular member. On the other hand, if the balloon of the second tubular member is not inflated, no flow control is possible.
• A method for removing cerebral occlusions is described in U.S. Pat. No. 6,165,199 to Barbut (Barbut '199). This patent describes a catheter having an aspiration port at its distal end that communicates with a vacuum at its proximal end. A perfusion port disposed in a lateral surface of the catheter may be used to enhance antegrade flow in collateral arteries. In use, the aspiration port is positioned proximal to an occlusion to provide a direct suction effect on the occlusion. The perfused flow in collateral arteries is intended to augment retrograde flow distal to the occlusion, such that the occlusion is dislodged via the pressure and directed toward the aspiration port. A chopping mechanism, e.g., an abrasive grinding surface or a rotatable blade, coupled to the aspiration port recognizes when the aspiration port is clogged. The chopping mechanism then engages to break up the occlusion and permit it to enter the aspiration port in smaller pieces.
• The device described in the Barbut '199 patent has several disadvantages. First, the use of a vacuum to aspirate the occlusion requires an external pressure monitoring device. The application of too much vacuum pressure through the aspiration port may cause trauma, i.e., collapse, to the vessel wall. Also, because the system is intended to dislodge the occlusion using a pressure differential, a chopping mechanism is required to prevent the entire mass from clogging the aspiration port. The use of a chopping mechanism, however, may generate such a large quantity of emboli that it may be difficult to retrieve all of the emboli. In addition, emboli generated by the action of the chopping mechanism may accumulate alongside the catheter, between the aspiration port and the distal balloon. Once this occurs, it is unclear how the emboli will be removed.
• Yet another drawback of the device described in the Barbut '199 patent is that high-pressure perfusion in collateral arteries may not augment retrograde flow distal to the occlusion as hypothesized. The patent indicates that high-pressure perfusion in collateral arteries via side ports in the catheter may be sufficient to cause an increase in pressure distal to the occlusion. Antegrade blood flow from the heart in unaffected arteries, e.g., other vertebral and/or carotid arteries, may make it difficult for the pressure differential induced in the contralateral arteries to be communicated back to the occluded artery in a retrograde fashion.
• Other methods for treating ischemic brain stroke have involved cerebral retroperfusion techniques. U.S. Pat. No. 5,794,629 to Frazee describes a method that comprises at least partially occluding the first and second transverse venous sinuses and introducing a flow of the patient's arterial blood to a location distal to the partial venous occlusions. As described in that patent, the infusion of arterial blood into the venous sinuses provides a retrograde venous flow that traverses the capillary bed to oxygenate the ischemic tissues and at least partially resolve ischemic brain symptoms.
• One drawback associated with the technique described in the Frazee patent is that the pressure in the transverse venous sinuses must be continuously monitored to ensure that cerebral edema is avoided. Because the veins are much less resilient than arteries, the application of sustained pressure on the venous side may cause brain swelling, while too little pressure may result in insufficient blood delivered to the arterial side.
• In addition to the foregoing methods to augment cerebral perfusion, several methods are known for mechanically removing clots to treat cerebral occlusions. U.S. Pat. No. 5,895,398 to Wensel et al. describes a shape-memory coil affixed to an insertion mandrel. The coil is contracted to a reduced profile state within the lumen of a delivery catheter, and the catheter is used to cross a clot. Once the coil is disposed distal to the clot, the coil id deployed. The coil then is retracted proximally to engage and remove the clot.
• A primary drawback associated with the Wensel device is that the deployed coil contacts the intima of the vessel, and may damage to the vessel wall when the coil is retracted to snare the occlusion. Additionally, the configuration of the coil is such that the device may not be easily retrieved once it has been deployed. For example, once the catheter has been withdrawn and the coil deployed distal to the occlusion, it will be difficult or impossible to exchange the coil for another of different dimensions.
• U.S. Pat. No. 5,972,019 to Engelson et al. describes a deployable cage assembly that may be deployed distal to a clot. Like the Wensel device, the Engelson device is depicted as contacting the intima of the vessel, and presents the same risks as the Wensel device. In addition, because the distal end of the device comprises a relatively large profile, the risk of dislodging emboli while crossing the clot is enhanced, and maneuverability of the distal end of the device through tortuous vasculature may be reduced.
• In view of these drawbacks of previously known clot removal apparatus and methods, it would be desirable to provide apparatus and methods for controlling hemodynamic properties at selected locations in the cerebral vasculature, e.g., the Circle of Willis and communicating vessels.
• It also would be desirable to provide apparatus and methods for removal and recovery of thrombi and/or emboli above the carotid bifurcation.
• It still further would be desirable to provide apparatus and methods that quickly and efficiently treat cerebral occlusions.
• It still further would be desirable to provide apparatus and methods for selectively providing retrograde and/or antegrade flow to desired regions in the cerebral vasculature to effectively remove emboli.
SUMMARY OF THE INVENTION
• In view of the foregoing, it is an object of the present invention to provide apparatus and methods for controlling hemodynamic properties at selected locations in the cerebral vasculature.
• It is also an object of the present invention to provide apparatus and methods for removal and recovery of thrombi and/or emboli above the carotid bifurcation.
• It is a further object of the present invention to provide apparatus and methods that quickly and efficiently treat cerebral occlusions.
• It still a further object of the present invention to provide apparatus and methods for selectively providing retrograde and/or antegrade flow to desired regions in the cerebral vasculature to effectively remove emboli.
• These and other objects of the present invention are accomplished by providing a stroke treatment system comprising an emboli removal catheter and one or more flow control devices suitable for manipulating blood flow in the cerebral vasculature. The stroke treatment system may facilitate the introduction and subsequent removal of clot lysing agents, or further comprise a thrombectomy element.
• In a preferred embodiment, the emboli removal catheter is transluminally inserted and disposed in the common carotid artery CCA, and comprises a flexible catheter having an occlusive member disposed on its distal end. The occlusive member is configured to be deployed to anchor the catheter and occlude antegrade flow in the CCA. A separate occlusive element is configured to pass through a lumen of the emboli removal catheter, and is deployed in the external carotid artery ECA to occlude flow through that vessel.
• One or more flow control devices, each having a rapidly deployable occlusive member, then are positioned at selected locations, e.g., in the subclavian arteries, and may be deployed to isolate or redistribute flow through the cerebral vasculature. Preferably, the flow control devices occlude blood flow in the vertebral and carotid arteries in the hemisphere in which the occlusion is not located. This temporarily influences flow in the opposing hemisphere. Preferably, the flow control devices are provided in sufficient number that, when deployed, the flow control devices substantially influence the flow dynamic of mid-cerebral artery.
• Once the foregoing components have been deployed, a lysing agent may be introduced into the vessel through a lumen of the emboli removal catheter. After an appropriate period, the occlusive members on one or more of the flow control devices may be collapsed to cause retrograde flow through the cerebral vasculature sufficient to flush the lysing agent and any emboli or debris from the vasculature into the emboli removal catheter. The stroke treatment system and flow control devices may then be withdrawn from the patient's vasculature.
• Alternatively, a thrombectomy element may be advanced transluminally via the ICA to a position just proximal of a cerebral occlusion, e.g., in the middle cerebral artery, after placement (but prior to deployment) of the flow control devices. The flow control devices then are deployed to selectively and temporarily redistribute or suspend flow in the cerebral vasculature. The thrombectomy element preferably is advanced to the site of the cerebral occlusion through a lumen of the emboli removal catheter.
• With flow controlled throughout the Circle of Willis and therefore the communicating mid-cerebral artery, the thrombectomy element then is engaged with the lesion. Actuation of the thrombectomy element preferably causes mechanical disruption of the emboli or thrombus, after which the element is retracted into the emboli removal catheter. By selectively de-actuating one or more of the flow control devices, retrograde or redistributed flow may be generated in the vasculature that cases emboli liberated during actuation of the thrombectomy element to be directed into the emboli removal catheter. The flow control devices then are withdrawn to reestablish antegrade blood flow.
• In a further alternative embodiment, a second emboli removal catheter may be disposed in a vertebral artery in lieu of one of the flow control devices. In this embodiment, the lumen of the second emboli removal catheter may be perfused with blood or saline under pressure to induce retrograde flow elsewhere in the cerebral vasculature, such as in the carotid or vertebral arteries. Additionally, chilled blood and/or drug agents may be delivered via the second catheter to induce mild hypothermia and/or altered pressure gradients at selected cerebral locations.
• The second emboli removal catheter may be used to enhance flow manipulation in the Circle of Willis and communicating vessels to facilitate removal of emboli via either retrograde or antegrade flow either independently or, or simultaneously with, use of the first emboli removal catheter.
BRIEF DESCRIPTION OF THE DRAWINGS
• Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments, in which:
• FIG. 1 provides a schematic overview of the portion of the vasculature in which the apparatus and methods of the present invention are intended for use;
• FIG. 2 provides an overview of the apparatus of the present invention deployed in a patient's vasculature;
• FIGS. 3A-3D are, respectively, a schematic view, and detailed side and sectional views of the distal end of an emboli removal catheter of the present invention;
• FIGS. 4A-4E provide detailed views of the proximal and alternative distal ends of the flow control devices of the present invention contracted and expanded states;
• FIGS. 5A-5B are views of alternative embodiments of low profile occlusive elements for occluding flow in the external carotid arteries;
• FIGS. 6A-6F depict thrombectomy wires having shape memory properties in contracted and deployed states;
• FIGS. 7A-7E illustrate alternative configurations for the thrombectomy wire ofFIG. 6;
• FIGS. 8A-8D illustrate thrombectomy wires configured to engage the fibrin strands of a thrombus;
• FIGS. 9A-9C describe an alternative thrombectomy device configured to engage the fibrin strands of a thrombus;
• FIGS. 10A-10E illustrate method steps for removing an occlusion using the apparatus ofFIG. 9;
• FIG. 11 describes a telescoping catheter configured to be advanced through the main catheter;
• FIGS. 12A-12D describe a telescoping catheter having an expandable distal section configured to be advanced through the main catheter;
• FIGS. 13A-13H illustrate method steps for controlling cerebral blood flow and removing thrombi and/or emboli in accordance with the present invention;
• FIGS. 14A-14B describe a catheter having an intake port configured to provide for retrograde and/or antegrade flow in either of the carotid or vertebral arteries;
• FIG. 15 illustrates a proximal assembly suitable for controlling retrograde and antegrade flow in the carotid and vertebral catheters ofFIG. 14; and
• FIGS. 16A-16B provide examples of manipulating cerebral flow using a combination of carotid and vertebral catheters, each having antegrade and retrograde flow potential.
DETAILED DESCRIPTION OF THE INVENTION
• Referring toFIG. 1, a schematic of the pertinent vasculature relating to the present invention is provided. Many cerebral obstructions that lead to stroke reside in the middle cerebral arteries MCA. To treat obstructions in the MCA, one approach involves percutaneously and transluminally advancing a therapeutic device to the site of the obstruction via the internal carotid artery ICA.
• It is well known in the art to percutaneously and transluminally advance a catheter in retrograde fashion toward coronary vasculature, e.g., via the femoral artery, external iliac artery, descending aorta DA and aortic arch AA. To access cerebral vasculature, including obstructions residing in the MCA, one approach is to further advance a catheter and/or therapeutic devices in antegrade fashion from the aortic arch AA, into the common carotid artery CCA, up through the ICA and into the middle cerebral artery MCA, as shown inFIG. 1.
• Treating occlusions in the MCA may generate emboli upon removal of the occlusion. Under normal blood flow conditions, such emboli may travel downstream from the original occlusion and cause ischemia. Accordingly, it is advantageous to manipulate blood flow characteristics in the cerebral vasculature to ensure that emboli generated in the MCA are effectively removed.
• The present invention manipulates cerebral blood flow by inhibiting flow from the heart into any of the vertebral arteries VA and common carotid arteries CCA. This may be achieved by disposing flow control devices in the subclavian arteries SA and/or brachiocephalic trunk BT, to temporarily inhibit flow from the aortic arch AA into any of the vertebral arteries VA and common carotid arteries CCA. This interruption of antegrade flow may advantageously alter flow in the Circle of Willis, as described hereinbelow.
• FIG. 2 provides an overview of the components of the system of the present invention, each of which are described in greater detail hereinbelow.
• Flow control devices8 havingocclusive elements6 are configured to be introduced into the patient's vasculature, e.g., via the radial or brachial arteries. When so positioned,occlusive elements6 preferably are positioned in the patient's left subclavian artery SA and brachiocephalic trunk BT, as shown.Occlusive elements6 may have any of a number of designs, with low profile mechanically self-expanding designs being preferred.
• Emboli removal catheter2 includes distalocclusive element4, and is configured to be percutaneously advanced in retrograde fashion through the descending aorta.Occlusive element4 preferably comprises a pear-shaped or funnel-shaped balloon as described in copending and commonly assigned U.S. patent application Ser. No. 09/418,727, which is incorporated herein by reference.Occlusive element4 preferably is positioned proximal to the carotid bifurcation, and then deployed to induce retrograde flow in the ICA by use of a venous return catheter (not shown) that communicates with the proximal end ofcatheter2.Balloon10, also described in the foregoing application, is deployed in the ECA to ensure that retrograde flow from the ICA is not carried in an antegrade fashion into the ECA.
• Flow control devices8 andemboli removal catheter2 are used to suspend antegrade flow in the cerebral arteries and to selectively suspend or redistribute flow in the cerebral vasculature. Once so-deployed, a lysing agent may be introduced to dissolve the clot, followed by selectively contracting one or more of the flow control devices to induce retrograde flow throughemboli removal catheter2.
• Alternatively, after placement offlow control devices8, but before they are deployed,thrombectomy wire12 may be introduced into the vessel containing the lesion.Flow control devices8 then may be deployed, as shown inFIG. 2, to prevent flow from the aortic arch AA into the right common carotid artery RCCA and the right and left vertebral arteries VA. Such selective manipulation of flow into the carotid and/or vertebral arteries alters flow characteristics in the cerebral vasculature, and permits retrograde flow through to be induced to flush emboli and debris into the lumen ofcatheter2 for removal.
• In the embodiment ofFIG. 2,thrombectomy wire12 comprisesknot14 that is deployed distal to the thrombusT. Thrombectomy wire12 and thrombus T then are retracted proximally into the lumen ofemboli removal catheter2, and any embolic fragments generated during this procedure are directed intocatheter2 by inducing localized retrograde flow. Once the thrombus is removed,flow control devices8 are contracted to reestablish flow to the cerebral vasculature.
• Referring now toFIG. 3A,stroke treatment apparatus40 constructed in accordance with the principles of the present invention is described.Apparatus40 comprisesemboli removal catheter41,wire45,venous return line52,tubing49 andoptional blood filter50.
• Catheter41 includes distalocclusive element42,hemostatic ports43aand43b, e.g., Touhy-Borst connectors,inflation port44, andblood outlet port48.Wire45 includesballoon46 that is inflated viainflation port47.Tubing49 couplesblood outlet port48 to filter50 andblood inlet port51 ofvenous return line52.
• Wire45 preferably comprises a small diameter flexible shaft having an inflation lumen that couplesinflatable balloon46 toinflation port47.Wire45 andballoon46 are configured to pass throughhemostatic ports43aand43band the aspiration lumen of catheter41 (seeFIGS. 3C and 3D), so thatballoon46 may be disposed in a communicating artery, e.g., the external carotid artery.Ports43aand43band the aspiration lumen ofcatheter41 are sized to permit additional interventional devices, such as thrombectomy wires, to be advanced through the aspiration lumen whenwire45 is deployed.
• Venous return line52 includeshemostatic port53,blood inlet port51 and a lumen that communicates withports53 and51 andtip54.Venous return line52 may be constructed in a manner per se known for venous introducer catheters.Tubing49 may comprise a suitable length of a biocompatible material, such as silicone. Alternatively,tubing49 may be omitted andblood outlet port48 ofcatheter41 andblood inlet port51 ofvenous return line52 may be lengthened to engage either end offilter50 or each other.
• With respect toFIGS. 3B and 3C, distalocclusive element42 comprises expandable funnel-shapedballoon55. In accordance with manufacturing techniques which are known in the art,balloon55 comprises a compliant material, such as polyurethane, latex or polyisoprene which has variable thickness along its length to provide a funnel shape when inflated.Balloon55 is affixed todistal end56 ofcatheter41 in an inverted fashion, for example, by gluing or a melt-bond, so that opening57 inballoon55 leads intoaspiration lumen58 ofcatheter41.Balloon55 preferably is wrapped and heat treated during manufacture so thatdistal portion59 of the balloon extends beyond the distal end ofcatheter41 and provides an atraumatic tip or bumper for the catheter.
• As shown inFIG. 3D,catheter41 preferably comprisesinner layer60 of low-friction material, such as polytetrafluoroethylene (“PTFE”), covered with a layer of flat stainlesssteel wire braid61 and polymer cover62 (e.g., polyurethane, polyethylene, or PEBAX).Inflation lumen63 is disposed withinpolymer cover62 and couplesinflation port44 toballoon55.
• Referring toFIG. 4, features of the flow control devices of the present invention are described. The flow control devices may comprise either an inflatable balloon or a mechanically deployable mechanism. InFIG. 4A, a preferred embodiment of the proximal end for a mechanically deployable mechanism comprisescontroller70,delivery port78, e.g., for delivering cardioplegic agents,deployment knob72 that is configured to slide withinslot74, andguidewire lumen76, which may comprise a self-sealing valve.Body73 houses a plurality of lumens, e.g., a mechanical deployment lumen, a therapeutic drug delivery lumen, and a guidewire lumen. In an alternative embodiment, for use in conjunction with an inflatable balloon,port78 may serve as an inflation/aspiration port whiledeployment knob72 andslot74 are omitted.
• FIGS. 4B-4C illustrate the distal end of the flow control device havinginflatable balloon82 in contracted and deployed states, respectively. In use,body73 is advanced over a guidewire viaguidewire lumen86.Radiopaque tip marker84 may be used to aid in fluoroscopically guiding the device.Balloon82 then is inflated by a lumen withinbody73 that communicates withport78.Port78 may communicate with a timing mechanism (not shown) that automatically deflatesballoon82 after a predetermined time, e.g., 15 seconds, to ensure that cerebral blood flow is not inhibited for a period so long as to cause cerebral compromise.
• FIGS. 4D-4E illustrate mechanicallydeployable mechanism92 comprisingflexible wires95 andimpermeable coating97 in contracted and deployed states, respectively.Impermeable coating97 comprises an elastomeric polymer, e.g., latex, polyurethane or polyisoprene. The proximal end ofdeployable mechanism92 is affixed tobody73. The distal end ofmechanism92 is affixed todistalmost section99, which in turn communicates with slidingmember93 that is configured to slide longitudinally within a lumen ofbody73.
• Upon actuatingdeployment knob72, i.e., proximally retractingknob72 withinslot74, slidingmember93 anddistalmost section99 are proximally retracted relative tobody73, to compressflexible wires95.Impermeable coating97 conforms to the shape ofwires95 to provide a plug-shaped occlusive member, as shown inFIG. 4E.Deployment knob72 may communicate with a timing mechanism (not shown) that automatically releasesmechanism92 after a predetermined time.
• Referring toFIG. 5, alternative embodiments forguide wire45 andballoon46 ofFIG. 3A are described for use in occluding a communicating artery, e.g., the external carotid artery. InFIG. 5A,occlusive device121 comprisesproximal hub120,hypo tube127,shaft128,balloon136 andcoil142.Hypo tube127 preferably comprises stainless steel, whileshaft128 preferably comprises a radiopaque material.Balloon136 is configured using a tubular balloon material, e.g., chronoprene, that is compliant in nature and provides a self-centering balloon when deployed. The proximal end ofballoon136 is secured toradiopaque shaft128 byband132 andtaper130. The distal end ofballoon136 is affixed tocoil142 viataper140.
• Core wire122 is slidably disposed withinhypo tube127 so that its proximal end and is disposed inproximal hub120 and its distal end is affixed to taper140. Fluid may be injected into the annulus surroundingcore wire122 so that the fluid exits intoballoon136 viainflation window134, thus permittingballoon136 to expand radially and longitudinally.Core wire122,taper140 andcoil142 may move distally to accommodate such linear extension.Stroke limiter123, disposed on the distal end ofcore wire122, ensures thatballoon136 does not extend longitudinally more a predetermined distance ‘x’.
• In the alternative embodiment ofFIG. 5B,occlusive device151 comprisesshaft152,balloon158, andcoil168.Shaft152 preferably comprises a radiopaque material and connects to a hypo tube similar to that ofFIG. 5A. The proximal components fordevice151, i.e., proximal toshaft152, are the same as the components that are proximal toshaft128 inFIG. 5A.
• Balloon158 is constrained at its proximal end byband156 havingproximal balloon marker157.Taper154 is provided on the proximal end ofband156 in alignment with the proximal end ofballoon158. The distal end ofballoon158 is everted, as shown inFIG. 5B, and secured withradiopaque band160 that provides a fluoroscopic reference for the distal boundary of the balloon.Taper164 further secures the everted distal section, sandwiching between the first and second folds.
• Core wire150 is distally affixed tocoil168 havingradiopaque marker170.Lumen159 communicates with an inflation port (not shown) at its proximal end and withinflation window136 at its distal end.Lumen159 permits the injection of fluids, e.g., saline, to deployballoon158.Core wire150 is slidably disposed in the hypo tube andshaft152 to prevent extension ofballoon158 up to a distance ‘x’, as indicated inFIG. 5A.
• Referring toFIG. 6, apparatus suitable for removing thrombi are described. InFIG. 6A,thrombectomy wire200 havingball202 affixed to its distal end is depicted in a contracted state withincoil204. In a preferred embodiment,thrombectomy wire200 comprises a shape-memory retaining material, for example, a Nickel Titanium alloy (commonly known in the art as Nitinol).
• The use of Nitinol generally requires the setting of a custom shape in a piece of Nitinol, e.g., by constraining the Nitinol element on a mandrel or fixture in the desired shape, and then applying an appropriate heat treatments, which are per se known.
• Coil204 coverswire202 along its length, up toball202. Ascoil204 is retracted proximally,wire200 self-expands to a predetermined knot configuration, as shown inFIG. 6B. In a preferred embodiment, the diameter ofwire200 is about 0.002 inches, the diameter ofball202 is about 0.014 inches, andcoil204 is manufactured using platinum. It should be appreciated that an outer sheath may be used in place ofcoil204, such that proximally retracting the outer sheath causeswire200 to deploy.
• Referring toFIG. 6C, a method for usingthrombectomy wire200 to snare a thrombus T, e.g., in middle cerebral artery MCA, is described.Thrombectomy wire200, initially contracted withincoil204, is advanced through a lumen ofcatheter2, then preferably is advanced in retrograde fashion via the internal carotid to the site of the cerebral lesion in the MCA. Under controlled flow conditions, i.e., conditions that will promote the flow of emboli towardcatheter2,wire200 andcoil204 pierce thrombus T, as shown inFIG. 6C.
• Coil204 then is retracted proximally with respect towire200 to self-deployshape memory wire200 at a location distal to thrombus T, as shown inFIG. 6D.Wire200 then is retracted to snare thrombus T, andball202 ofwire200 facilitates removal of the lesion.
• Referring toFIGS. 6E-6F, an alternative embodiment a thrombectomy wire of FIGS.6A-B is described. InFIG. 6E,thrombectomy wire205 havingdistal ball208 is delivered in a contracted state withinslidable sheath206.Thrombectomy wire205 is configured to self-deploy to a predetermined shape, e.g., via use of a shape memory material, upon proximal retraction ofsheath206.Coil207 overlaysslidable sheath206 and is affixed toball208 atpoints209aand209b, e.g., via a solder or weld.Sheath206 is initially provided in a distalmost position such that it abutsball208 and constrainswire205 along its length.Sheath206 advantageously enhances the distal pushability of the device, particularly when the device is advanced though an occlusion.
• Upon positioning the distal end ofwire205 at a location distal to the occlusion,sheath206 is retracted proximally to causewire205 to self-deploy to a knot-shaped configuration, as depicted inFIG. 6F.Coil207, affixed toball208 ofwire205, conforms to the shape ofwire205. The deployed knot-shaped device then is proximally retracted to snare the occlusion, according to methods described hereinabove.
• Referring toFIGS. 7A-7E, alternative embodiments for thrombectomy wires in accordance with the present invention are depicted. InFIG. 7A,thrombectomy wire210 comprises a plurality of intersecting hoops that deploy upon retraction of a coil or sheath.Hoops212 and214 may be orthogonal to each other, as shown inFIG. 7A. The hoops are designed to form a knot-shape to snare a thrombus in combination withball216. Additionally, there may be a series of intersecting hoops, as shown inFIG. 7B.Thrombectomy wire220 comprisesfirst knot222 andsecond knot224 separated by a distance ‘y’, although it will be obvious that any variation in the number of knots and their shapes are intended to fall within the scope of the present invention.
• Referring toFIG. 7C,thrombectomy wire230 comprises spiral-shapeddistal section232. The spiral shape is formed from a series of planar hoops, the diameter of hoops being slightly smaller with each successive hoop. As shown, the hoops ofspiral232 are depicted as being orthogonal to the main axis ofwire230. Elbow234 defines a bent section that connectsmain wire section236 tofirst hoop238. As shown,elbow234 is orthogonal tomain wire section236, however, it may be provided at any angle. Similarly, as shown inFIG. 7D,wire240 may comprise a plurality of spiral-shapedsections242 and244 separated by a distance ‘z’.
• InFIG. 7E,thrombectomy wire250 comprise a plurality of petal-shaped sections that deploy upon retraction of a coil or sheath. As shown, petal-shapedsections252 and254 are orthogonal to each other, however, they may be provided at any angle with respect tomain axis256 and each other, and any number of petal-shaped sections may be provided
• Referring toFIGS. 8A-8D, a further alternative thrombectomy device is illustrated.Device260 removes a lesion by organizing the fibrin strands of the lesion around the deployable wires using a rotational motion. Exemplary method steps for using the embodiments described inFIGS. 8A-8D are described inFIG. 10 hereinbelow.
• InFIG. 8A,thrombectomy device260 comprises at least onedeployable wire262 affixed at its proximal and distal ends atpoints266 and264, respectively.Deployable wire262 is initially contracted withincoil268, and whentubular member268, e.g., a coil or sheath, is retracted proximally,deployable wires262 self-expand to a predetermined shape, as shown. Asdeployable wires262 are rotated within the thrombus itself, the fibrin strands of the thrombus will become engaged with and wrap arounddeployable wires262.
• InFIG. 8B,alternative thrombectomy device270 comprises at least onedeployable wire274 that is distally affixed to wire270 atpoint276. The proximal end ofwire274 is secured to slidingmember272, which slides longitudinally overwire271. Whenwire271 and slidingmember272 move with respect to each other,deployable wire274 either radially outwardly deflects, as shown, or flattens out for a contracted position.
• InFIG. 8C,thrombectomy device280 comprisesdeployable wire282 configured to form a plurality ofloops285 aroundshaft283. The distal end ofdeployable wire282 is affixed toshaft283 atpoint284, which may serve as an atraumatic tip for guiding the device and piercing the thrombus. The proximal end ofdeployable wire282 is affixed totube281.Tube281 spans-the length of the device and has a proximal end that is manipulated by the physician. Distally advancingtube281 overshaft283 deploysloops285, as shown, while proximally retractingtube281 with respect toshaft283contracts loops285. In the deployed state, rotating the device about its axis will causeloops285 ofwire282 to engage the thrombus and wrap the fibrin strands about the device, as described inFIG. 10 hereinbelow.
• InFIG. 8D,thrombectomy device290 comprises a plurality of shape-memory, arrowhead-shapedwires292 that are distally affixed to each other atpoint294 and proximally affixed atjunction298.Wires292 are initially contracted withintubular member296, e.g., a coil or sheath, and upon proximal retraction oftubular member296,wires292 self-deploy to the configuration shown.
• Apparatus and methods for organizing fibrin strands of a thrombus around a thrombectomy device are further described with respect toFIGS. 9 and 10. InFIG. 9A,thrombectomy device300 comprisesproximal segment306,catheter302, anddistal segment304.Proximal segment306 comprisesthumb ring308,proximal body310, anddeployment knob312 that slides longitudinally withinslot314.Distal segment304 comprises at least onedeployable wire316 andatraumatic tip318.
• FIG. 9B provides a schematic view ofdistal segment304.Deployable wire316 preferably comprises a shape memory material that communicates withdeployment knob312 at its proximal end, as described inFIG. 9C hereinbelow. The distal end ofdeployable wire316 is affixed toatraumatic tip318, e.g., using a solder or weld.Deployable wire316 is delivered in a contracted state, i.e., such that it does not substantially extend radially beyondcatheter302. Upon actuation ofdeployment knob312,wire316 self-expands viaholes317 to form a whisk-type element, as shown.Catheter302 may be provided with one or more working lumens that communicate withdelivery port305 to permit the delivery of fluids, e.g., saline or other drugs that facilitate clot removal.
• FIG. 9C provides a schematic view ofproximal segment306. The distal end ofdeployable wire316 is configured to deploy fromcatheter302. The proximal end ofcatheter302 is affixed toouter shaft322, which preferably has a square cross-section.Outer shaft322 is keyed toinner shaft320.Inner shaft320 is keyed to slidablymore actuator323, so that rotational motion of one element causes rotation of the other.Catheter302 further is affixed toretainer315, which permitscatheter302 to rotate freely relative toproximal body310.
• Thumb ring308 communicates withactuator323 viajoint321.Joint321 permits rotational motion ofactuator323 with respect tothumb ring308.Actuator323 is affixed torotational member326 at its distal end, which in turn is affixed toinner shaft320.Rotational member326 comprisesknob327 that is configured to slidably rotate withingroove328 in the wall ofbody310.
• Deployable wire316 is deployed by slidingdeployment knob312 withinslot314.Deployment knob312 comprises a rounded pin that engages with a groove ofring324. This engagement distally advancesring324 withinslot325 ofcatheter302.Deployable wire316 is affixed to ring324, such that distally advancingring324 viadeployment knob312 allowswire316 to self-deploy. The rounded pin engagement between knob.312 and the groove ofring324 further permits free axial rotation ofring324 whileknob312 is stationary.
• Withwire316 deployed,thumb ring308 is depressed with a force that overcomes a resistance force provided byspring330.Depressing thumb ring308 in turn causesrotational member326 to be advanced distally viagroove328. When a thumb force is no longer applied, the resistance ofspring330 then pushes rotatingmember326 in a proximal direction viagroove328. This in turn causes rotation ofrotational member326,inner shaft320,outer shaft322 andcatheter302. The rotation ofcatheter302 generates rotation ofthrombectomy wire316.
• The rotation ofthrombectomy wire316 may be clockwise, counterclockwise, or a combination thereof by manipulating the profile ofgroove328. The rotational speed may be controlled by varying the resistance ofspring330, and the duration of rotation can be controlled by varying the length in whichrotational member326 can longitudinally move. Alternatively, another force transmission means, e.g., a motor, may be coupled to the proximal end to provide for controlled axial rotation ofcatheter302.
• FIG. 10 illustrate method steps for removing thrombi using any of the thrombectomy devices described inFIGS. 8-9. In a first step,catheter302 is advanced throughcatheter2 ofFIG. 2, then advanced in a retrograde fashion toward the occlusion.Catheter302 may be advanced via the internal carotid artery to treat a lesion T located in a cerebral vessel V, e.g., the middle cerebral artery.Atraumatic tip318 serves to protect vessel walls ascatheter302 is advanced through tortuous anatomy. At this time,flow control devices8 ofFIG. 2 are deployed to cause retrograde blood to flow in the directions indicated.
• Tip318 ofcatheter302 then is advanced to pierce thrombus T, as shown inFIG. 10B.Deployment knob312 ofFIG. 9 then is actuated to deploy at least onedeployable wire316 within thrombusT. Thumb ring308 then is depressed, resulting in the controlled rotation ofdeployable wire316, such that the wire engages the fibrin strands of thrombus T. As the fibrin strands are wound aboutdeployable wire316, the diameter of thrombus T decreases, as shown inFIG. 10D. Blood flows in a retrograde fashion, i.e., towardcatheter2 which is positioned in the common carotid artery, and any emboli E generated during the procedure will be removed by the catheter in the process. It should be noted thatdeployable wire316 is designed such that it does not contact the inner wall of vessel V. Once the thrombus T is sufficiently wound aboutdeployable wire316, as shown inFIG. 10E,catheter302 may be retracted intocatheter2.
• Referring toFIG. 11, an alternative embodiment of the present invention is described wherein a second catheter is advanced to a location in closer proximity to the occlusive lesion.Main catheter340 having distalocclusive element342 is positioned, for example, in the common carotid artery, as described inFIG. 2.Recovery catheter344 having distalocclusive element346 andradiopaque marker347 is configured to telescope within the lumen ofmain catheter340.
• In a preferred method,main catheter340 is disposed in the common carotid artery. Retrograde flow then is established usingvenous return line52 ofFIG. 3A according to methods described hereinabove. A0.014 inch neuro guidewire350 then is advanced via the lumen ofmain catheter340 to the site of the cerebral occlusion, andneuro guidewire350 is disposed distal to the lesion. In this illustration, an occlusion (not shown) would be located approximately within an interval ‘L’, e.g., in the middle cerebral artery.Recovery catheter344 then is advanced distally overneuro guidewire350 and is positioned proximal to occlusion ‘L’. Upon positioningrecovery catheter344, occlusivedistal element346 is deployed.
• Neuro catheter348 then is advanced overneuro guidewire350, and the distal end ofneuro catheter348 is disposed at a location distal to occlusion ‘L’, as shown.Neuro guidewire350 then is retracted proximally and removed from withinneuro catheter348, which comprises a relatively small lumen. Withneuro guidewire350 removed, a thrombectomy wire is advanced distally through the lumen ofneuro catheter348, and the thrombectomy wire takes the place ofguidewire350 inFIG. 11.Neuro catheter348 then is proximally retracted, andthrombectomy wire350 is deployed to treat the occlusion according to methods described hereinabove.
• Recovery catheter344 comprises at least oneblood venting hole345. The established retrograde flow throughcatheter344 usingvenous return line52 induces retrograde flow in at least the internal carotid artery viablood venting hole345. Flow intoventing hole345 may be manipulated by actuatinginner sheath349, e.g., by longitudinally slidinginner sheath349 withincatheter344, or rotatinginner sheath349 relative to its longitudinal axis.
• Advantageously, the distal end ofrecovery catheter344 is positioned in close proximity to the lesion, so thatwire348 and any emboli generated are immediately confined withinrecovery catheter344. Furthermore, advancingrecovery catheter344 via the internal carotid artery eliminates the need for deployingballoon10 ofFIG. 2 in the external carotid artery.
• Referring toFIG. 12, a further alternative embodiment of the present invention is described wherein a second catheter is advanced to a location in closer proximity to the occlusive lesion.Main catheter360 having distalocclusive element362 is positioned, for example, in the common carotid artery, as described inFIG. 2.Recovery catheter364 comprises a wire weave configuration and may be manufactured using a shape memory material, e.g., Nitinol, as described hereinabove.
• Recovery catheter364 further comprises bloodimpermeable membrane365, such as latex, polyurethane or polyisoprene, that encloses the wire weave ofrecovery catheter364. The elastic properties of bloodimpermeable membrane365 allow it to conform to the contracted and expanded states ofrecovery catheter364.
• Recovery catheter364 is advanced in a contracted state withinouter sheath366. As described in applicants' commonly assigned, co-pending application Ser. No. 09/916,349, which is herein incorporated by reference,outer sheath366 is retracted proximally to cause occlusivedistal section368 to self-expand to a predetermined deployed configuration, as shown inFIG. 12A. Occlusivedistal section368 may be sized for different vessels, e.g., the middle cerebral arteries, so that the distal end ofrecovery catheter364 is disposed proximal to an occlusion, e.g., as depicted at location ‘L’.Mouth369 provides a relatively large distal opening, i.e., flush with the inner wall of the targeted vessel.
• Neuro catheter370 then is advanced overneuro guidewire372, as described hereinabove inFIG. 11, and a thrombectomy wire is exchanged forneuro guidewire372.Neuro catheter370 is proximally retracted, andthrombectomy wire372 removes the occlusion at location ‘L’ according to methods described hereinabove. Upon removing the occlusion,thrombectomy wire372 is retracted intomouth369, along with any emboli generated during the procedure.
• It will be advantageous to collapsemouth369 upon completion of the procedure, to prevent thrombi and/or emboli from exitingremoval catheter364.FIGS. 12B-12D illustrate a method for effectively collapsingmouth369 proximally to distally, as shown.FIG. 12B showsouter sheath366 havingradiopaque marker367 in a proximally retracted position that allows occlusivedistal section368 to deploy. After directing thrombi and/or emboli intomouth369,outer sheath366 is advanced distally to collapsemouth369, as shown sequentially inFIGS. 12C-12D. This effectively confines thrombi and/or emboli withinmouth369.
• Referring now toFIG. 13, a method for using the apparatus described hereinabove to treat stroke, in accordance with principles of the present invention, is described. InFIG. 13A,flow control devices400 havingcontrollers402 are introduced into the patient's vasculature in a contracted state, e.g., via the radial or brachial arteries, and preferably are positioned in the patient's left subclavian artery and brachiocephalic trunk, as shown. It will be appreciated by those skilled in the art that varying the number of flow control devices and their placements is intended to fall within the scope of the present invention. Blood flow occurs in the directions indicated.
• Referring toFIG. 13B,catheter404 ofFIG. 3A is positioned in the common carotid artery CCA usingguide wire406.Catheter404 is positioned proximal to the carotid bifurcation, as shown, preferably in the hemisphere in which the cerebral occlusion is located.Balloon408, for example, as described inFIG. 5, then is disposed in the external carotid artery and deployed, as shown inFIG. 13C.
• Referring toFIG. 13D, distalocclusive element412 ofcatheter404 is deployed to occlude antegrade flow in the selected CCA.Venous return catheter52 ofFIG. 3A then is placed in a remote vein, such that negative pressure invenous return catheter52 during diastole establishes a continuous flow through the lumen ofcatheter404. This induces retrograde flow in the ICA, as depicted inFIG. 13D. Athrombectomy wire414, for example, as described inFIGS. 6-10, is advanced throughcatheter404 and into the cerebral vasculature via the ICA.
• Referring toFIG. 13E, a view of the cerebral vasculature under the conditions described inFIG. 13D is shown.Thrombectomy wire414 has been advanced to a location just proximal to thrombus T, for example, in middle cerebral artery MCA.
• At this time,flow control devices400 then are deployed usingcontroller402 to formocclusive elements420, as shown inFIG. 13F. As depicted, flow from aortic arch AA into brachiocephalic trunk BT and left subclavian artery SA are inhibited, which in turn inhibits flow into the vertebral arteries VA and right CCA, as shown. It will be apparent to those skilled in the art that occlusiveelements420 may be selectively placed at other locations to permit and/or inhibit flow into the selected locations of the cerebral vasculature.
• The deployment ofocclusive elements420 controls flow in the Circle of Willis, as shown inFIG. 13G. In this example, since arterial flow into the vertebral arteries VA and the right internal carotid artery has been inhibited, emboli that are generated will be directed in a retrograde fashion towardcatheter404 via the left internal carotid artery. The distal end ofthrombectomy wire414 then pierces thrombus T anddeployable knot416 is deployed distal to the thrombus, as shown inFIG. 13G. Alternatively, other thrombectomy wire configurations may be used to treat the lesion, as described inFIGS. 6-10.
• Deployable knot416 ofthrombectomy wire414 snares thrombus T, as shown inFIG. 13H, and subsequently is retracted intocatheter404. Any emboli generated during the procedure will be directed intocatheter404 via the established retrograde flow.Occlusive elements420, distalocclusive element412, and external carotidocclusive device408 then are contracted, andcatheter404 may be removed from the patient.
• It should be noted that the method steps described inFIG. 13 may be used in combination with any of the apparatus described hereinabove. For example,recovery catheters344 and364 ofFIGS. 11 and 12, respectively, may be advanced throughcatheter404 ofFIG. 13. Additionally, any of the snaring thrombectomy devices ofFIG. 7 or the rotating thrombectomy devices ofFIG. 8 may be used in place ofthrombectomy wire414 as depicted. Similarly, any of the occlusive devices described inFIGS. 4B-4E andFIGS. 5A-5B may be used in place ofocclusive elements420 and408, respectively.
• Referring toFIGS. 14-16, further apparatus and methods is accordance with principles of the present are described. InFIG. 14A,catheter430 may be configured for use in any of the carotid and vertebral arteries.Catheter430 comprisesblood intake port432, distalocclusive element436 andradiopaque tip marker435.Occlusive element436 comprises proximal anddistal tapers438 and440, respectively.Inner sheath434 is configured for longitudinal sliding motion withincatheter430.
• Inner sheath434 is initially provided in a distalmost position that coversblood intake port432 in a closed state, as shown inFIG. 14A. Deployment ofocclusive element436 inhibits antegrade blood flow in vessel V, at which time therapeutic drugs and/or devices may be delivered to site of the occlusion vialumen437.
• Retrograde blood flow in vessel V is induced by placingvenous return catheter52 ofFIG. 3A into a remote vein, according to methods described hereinabove. The retrograde flow throughlumen437 induces retrograde flow distal toocclusive element436.Distal taper440 facilitates retrograde blood flow intolumen437.
• If antegrade flow is desired,inner sheath434 may be retracted proximally to exposeblood intake port432, as shown inFIG. 14B. This permits antegrade flow to enterintake port432 and continue flowing in an antegrade direction distal toocclusive element436.Proximal taper438 is configured to enhance antegrade blood flow intointake port432.
• Cerebral flow manipulation may be enhanced by placing a first catheter in accordance withFIG. 14 in a common carotid artery and a second catheter in a vertebral artery, each on the hemisphere of the occlusion.FIG. 15 depicts apparatus suitable for controlling cerebral flow when utilizing one carotid and one vertebral catheter in combination. InFIG. 15,catheters450 and470 are configured to be disposed in the common carotid and vertebral arteries, respectively. However, it should be appreciated by those skilled in the art that two vertebral catheters may be used, i.e., one in each of the vertebral arteries, in combination with the carotid catheter.
• Catheters450 and470 each comprises a plurality of lumens.Inner sheaths456 and476 are configured to slide longitudinally within an outermost lumen of their respective catheters.Inner sheaths456 and476 communicate withdeployment knobs452 and472. Slidingdeployment knobs452 and472 withinslots454 and474 controls movement ofinner sheaths456 and476, respectively.
• Inflation ports462 and482 communicate with lumens of their respective catheters. Workinglumens458,460,478 and480 provide each catheter with two working lumens, e.g., for advancing guide wires and thrombectomy wires, and may be provided with hemostatic valves, for example, Touhy-Borst connectors.
• Biocompatible tubing459 and461 enable fluid communication betweenretrograde flow controller465 and lumens ofcatheter450 and470, respectively.Retrograde flow controller465 further communicates withvenous return line52 ofFIG. 3A viatubing463. Switch467 ofretrograde flow controller465permits tubing459 and461 to communicate with retrograde flow oftubing463 singularly or in combination, or switch467 may inhibit retrograde flow altogether. For example, when retrograde flow is induced intubing463 viavenous return line52, either one oftubing459 and461, both, or neither may experience retrograde flow based on the position ofswitch467.
• The apparatus described inFIG. 15 allow a physician to provide either retrograde, antegrade or hemostatic flow from two opposing cerebral locations, i.e., the carotid and vertebral arteries. The lumens of the vertebral and/or carotid catheters may be perfused with blood or saline under pressure to manipulate flow at selected cerebral locations. The apparatus further allows for the injection of therapeutic drugs and/or thrombectomy devices. Chilled blood or saline may be delivered via either of the carotid and vertebral catheters to induce mild hypothermia at selected cerebral locations, while drug agents may be used to selectively alter the pressure gradients.
• Additionally, lytic agents may be delivered via either of the carotid or vertebral catheters to aid in the disintegration of the occlusion. Such lytic agents preferably are used in combination with the flow manipulation techniques in accordance with the present invention, to direct emboli resulting from the lytic process into the removal catheter(s).
• Referring toFIG. 16, method steps are described to manipulate cerebral flow in a variety of ways using a combination of carotid and vertebral catheters. InFIG. 16A, afirst catheter500 comprisingocclusive element502 andblood intake port504 is disposed in the left common carotid artery CCA.Inner sheath506 is provided in a distalmost position to prevent fluid from enteringintake port504, andocclusive element502 is deployed to occlude antegrade flow.Balloon508, e.g., as described inFIG. 5, then is deployed in the ECA.
• Similarly, asecond catheter520 comprisingocclusive element522 andblood intake port524 is disposed in the left and/or right vertebral artery VA. In this example, one catheter is shown.Inner sheath526 is provided in a distalmost position to prevent fluid from entering intake port544, andocclusive element522 is deployed to occlude antegrade flow.
• Venous return line52 ofFIG. 3A then is placed in a remote vein, according to methods described hereinabove, and retrograde flow may be induced either in the ICA, VA, or both arteries based onswitch467 ofFIG. 15. As depicted inFIG. 16A,switch467 is set to a position that permits retrograde flow to be induced in both the carotid and vertebral catheters.
• At this time, any of the flow control devices described inFIG. 4 optionally may be deployed to occlude flow in the opposing carotid and vertebral arteries, according to methods described hereinabove. In this example, this ensures that blood flow is controlled in the left hemisphere.
• The retrograde flow fromcatheters500 and520 encourages blood flowing in the middle cerebral artery MCA to flow toward both catheters, as indicated by the arrows inFIG. 16A.Thrombectomy wire510 havingdeployable knot512 then is advanced into the MCA via the ICA and snares thrombus T, according to methods described hereinabove. Emboli E generated during the procedure are directed toward either one ofcatheters500 and520 for removal. Advantageously, the use of two catheters in combination provides for improved aspiration of the targeted vessel, in this case, the MCA.
• Referring toFIG. 16B,deployable knob472 ofFIG. 15 is proximally retracted to retractinner sheath526 and exposeintake port524 ofcatheter520. Switch467 ofretrograde flow controller465 is positioned for retrograde flow only throughcatheter500. This allows antegrade flow in vertebral artery VA to enterintake port524 and continue flowing in an antegrade direction into basilar artery BA and toward the MCA via the path indicated. The combination of antegrade flow from the left VA and either antegrade or retrograde flow from the left ICA directs emboli E generated in the MCA to flow primarily intocatheter500.
• There are several other variations possible for manipulating flow in the cerebral vasculature, to more efficiently deliver therapeutic drugs and/or direct emboli into a removal catheter. For example, therapeutic drugs may be delivered to the MCA whenswitch467 ofFIG. 15 inhibits venous flow into bothcatheters500 and520, and each ofblood intake ports504 and524 are closed. Therapeutic drugs may be delivered via eitherport458 or478 into the MCA, or mild hypothermia may be induced by introducing chilled blood or saline.
• It should be appreciated that varying the settings ofretrograde flow controller465 anddeployable knobs452 and472 may provide for any combination of antegrade, retrograde, or hemostatic flow in the carotid and vertebral arteries. There are too many flow combinations to illustrate, however, it is intended that therapeutic drugs, thrombectomy devices, cardioplegic and/or brain chilling agents may be delivered under a variety of controlled cerebral flow conditions. Additionally, a neuro guidewire and neuro catheter, as described inFIGS. 11 and 12A hereinabove, may be used in conjunction withthrombectomy wire510 ofFIG. 16.
• While preferred illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made therein without departing from the invention. The appended claims are intended to cover all such changes and modifications that fall within the true spirit and scope of the invention.

Claims (8)

1-25. (canceled)

26. Apparatus suitable for manipulating cerebral blood flow characteristics, the apparatus comprising:

a catheter configured for introduction into a first blood vessel, having proximal and distal ends, a lumen extending therebetween, and an occlusive element affixed to the distal end, the occlusive element having an opening that communicates with the lumen, the occlusive element having a contracted position suitable for transluminal insertion and an expanded position wherein the occlusive element occludes antegrade flow in a vessel; and

at least one flow control device adapted for introduction into a second blood vessel, having proximal and distal ends and a flow control element disposed at the distal end;

wherein when the occlusive element and flow control device are deployed in the first and second blood vessels, they control perfusion in a third blood vessel distal to the first and second blood vessels.

27. The apparatus ofclaim 26, further comprising a thrombectomy wire configured to be advanced into the third blood vessel.

28. The apparatus ofclaim 26, wherein the occlusive element comprises an inflatable balloon.

29. The apparatus ofclaim 28, wherein the inflatable balloon forms a tapered entrance to the lumen when the inflatable balloon is inflated.

30. The apparatus ofclaim 26, wherein the flow control element is an inflatable balloon.

31. The apparatus ofclaim 26, wherein the third blood vessel is an MCA.

32. The apparatus ofclaim 27, wherein the third blood vessel is an MCA.

Images