US 20050124973 A1
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).
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.
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The present application is a divisional of copending U.S. patent application Ser. No. 09/972,225, filed Oct. 4, 2001.
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.
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 in
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.
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.
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:
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 in
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.
Flow control devices 8 having occlusive elements 6 are configured to be introduced into the patient's vasculature, e.g., via the radial or brachial arteries. When so positioned, occlusive elements 6 preferably are positioned in the patient's left subclavian artery SA and brachiocephalic trunk BT, as shown. Occlusive elements 6 may have any of a number of designs, with low profile mechanically self-expanding designs being preferred.
Emboli removal catheter 2 includes distal occlusive element 4, and is configured to be percutaneously advanced in retrograde fashion through the descending aorta. Occlusive element 4 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 element 4 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 of catheter 2. Balloon 10, 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 devices 8 and emboli removal catheter 2 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 through emboli removal catheter 2.
Alternatively, after placement of flow control devices 8, but before they are deployed, thrombectomy wire 12 may be introduced into the vessel containing the lesion. Flow control devices 8 then may be deployed, as shown in
In the embodiment of
Referring now to
Catheter 41 includes distal occlusive element 42, hemostatic ports 43 a and 43 b, e.g., Touhy-Borst connectors, inflation port 44, and blood outlet port 48. Wire 45 includes balloon 46 that is inflated via inflation port 47. Tubing 49 couples blood outlet port 48 to filter 50 and blood inlet port 51 of venous return line 52.
Wire 45 preferably comprises a small diameter flexible shaft having an inflation lumen that couples inflatable balloon 46 to inflation port 47. Wire 45 and balloon 46 are configured to pass through hemostatic ports 43 a and 43 b and the aspiration lumen of catheter 41 (see
Venous return line 52 includes hemostatic port 53, blood inlet port 51 and a lumen that communicates with ports 53 and 51 and tip 54. Venous return line 52 may be constructed in a manner per se known for venous introducer catheters. Tubing 49 may comprise a suitable length of a biocompatible material, such as silicone. Alternatively, tubing 49 may be omitted and blood outlet port 48 of catheter 41 and blood inlet port 51 of venous return line 52 may be lengthened to engage either end of filter 50 or each other.
With respect to
As shown in
Upon actuating deployment knob 72, i.e., proximally retracting knob 72 within slot 74, sliding member 93 and distalmost section 99 are proximally retracted relative to body 73, to compress flexible wires 95. Impermeable coating 97 conforms to the shape of wires 95 to provide a plug-shaped occlusive member, as shown in
Core wire 122 is slidably disposed within hypo tube 127 so that its proximal end and is disposed in proximal hub 120 and its distal end is affixed to taper 140. Fluid may be injected into the annulus surrounding core wire 122 so that the fluid exits into balloon 136 via inflation window 134, thus permitting balloon 136 to expand radially and longitudinally. Core wire 122, taper 140 and coil 142 may move distally to accommodate such linear extension. Stroke limiter 123, disposed on the distal end of core wire 122, ensures that balloon 136 does not extend longitudinally more a predetermined distance x.
In the alternative embodiment of
Balloon 158 is constrained at its proximal end by band 156 having proximal balloon marker 157. Taper 154 is provided on the proximal end of band 156 in alignment with the proximal end of balloon 158. The distal end of balloon 158 is everted, as shown in
Core wire 150 is distally affixed to coil 168 having radiopaque marker 170. Lumen 159 communicates with an inflation port (not shown) at its proximal end and with inflation window 136 at its distal end. Lumen 159 permits the injection of fluids, e.g., saline, to deploy balloon 158. Core wire 150 is slidably disposed in the hypo tube and shaft 152 to prevent extension of balloon 158 up to a distance x, as indicated in
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.
Coil 204 covers wire 202 along its length, up to ball 202. As coil 204 is retracted proximally, wire 200 self-expands to a predetermined knot configuration, as shown in
Coil 204 then is retracted proximally with respect to wire 200 to self-deploy shape memory wire 200 at a location distal to thrombus T, as shown in
Upon positioning the distal end of wire 205 at a location distal to the occlusion, sheath 206 is retracted proximally to cause wire 205 to self-deploy to a knot-shaped configuration, as depicted in
Apparatus and methods for organizing fibrin strands of a thrombus around a thrombectomy device are further described with respect to
Thumb ring 308 communicates with actuator 323 via joint 321. Joint 321 permits rotational motion of actuator 323 with respect to thumb ring 308. Actuator 323 is affixed to rotational member 326 at its distal end, which in turn is affixed to inner shaft 320. Rotational member 326 comprises knob 327 that is configured to slidably rotate within groove 328 in the wall of body 310.
Deployable wire 316 is deployed by sliding deployment knob 312 within slot 314. Deployment knob 312 comprises a rounded pin that engages with a groove of ring 324. This engagement distally advances ring 324 within slot 325 of catheter 302. Deployable wire 316 is affixed to ring 324, such that distally advancing ring 324 via deployment knob 312 allows wire 316 to self-deploy. The rounded pin engagement between knob. 312 and the groove of ring 324 further permits free axial rotation of ring 324 while knob 312 is stationary.
With wire 316 deployed, thumb ring 308 is depressed with a force that overcomes a resistance force provided by spring 330. Depressing thumb ring 308 in turn causes rotational member 326 to be advanced distally via groove 328. When a thumb force is no longer applied, the resistance of spring 330 then pushes rotating member 326 in a proximal direction via groove 328. This in turn causes rotation of rotational member 326, inner shaft 320, outer shaft 322 and catheter 302. The rotation of catheter 302 generates rotation of thrombectomy wire 316.
The rotation of thrombectomy wire 316 may be clockwise, counterclockwise, or a combination thereof by manipulating the profile of groove 328. The rotational speed may be controlled by varying the resistance of spring 330, and the duration of rotation can be controlled by varying the length in which rotational member 326 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 of catheter 302.
Tip 318 of catheter 302 then is advanced to pierce thrombus T, as shown in
In a preferred method, main catheter 340 is disposed in the common carotid artery. Retrograde flow then is established using venous return line 52 of
Neuro catheter 348 then is advanced over neuro guidewire 350, and the distal end of neuro catheter 348 is disposed at a location distal to occlusion L, as shown. Neuro guidewire 350 then is retracted proximally and removed from within neuro catheter 348, which comprises a relatively small lumen. With neuro guidewire 350 removed, a thrombectomy wire is advanced distally through the lumen of neuro catheter 348, and the thrombectomy wire takes the place of guidewire 350 in
Recovery catheter 344 comprises at least one blood venting hole 345. The established retrograde flow through catheter 344 using venous return line 52 induces retrograde flow in at least the internal carotid artery via blood venting hole 345. Flow into venting hole 345 may be manipulated by actuating inner sheath 349, e.g., by longitudinally sliding inner sheath 349 within catheter 344, or rotating inner sheath 349 relative to its longitudinal axis.
Advantageously, the distal end of recovery catheter 344 is positioned in close proximity to the lesion, so that wire 348 and any emboli generated are immediately confined within recovery catheter 344. Furthermore, advancing recovery catheter 344 via the internal carotid artery eliminates the need for deploying balloon 10 of
Recovery catheter 364 further comprises blood impermeable membrane 365, such as latex, polyurethane or polyisoprene, that encloses the wire weave of recovery catheter 364. The elastic properties of blood impermeable membrane 365 allow it to conform to the contracted and expanded states of recovery catheter 364.
Recovery catheter 364 is advanced in a contracted state within outer sheath 366. As described in applicants' commonly assigned, co-pending application Ser. No. 09/916,349, which is herein incorporated by reference, outer sheath 366 is retracted proximally to cause occlusive distal section 368 to self-expand to a predetermined deployed configuration, as shown in
Neuro catheter 370 then is advanced over neuro guidewire 372, as described hereinabove in
It will be advantageous to collapse mouth 369 upon completion of the procedure, to prevent thrombi and/or emboli from exiting removal catheter 364.
Referring now to
At this time, flow control devices 400 then are deployed using controller 402 to form occlusive elements 420, as shown in
The deployment of occlusive elements 420 controls flow in the Circle of Willis, as shown in
Deployable knot 416 of thrombectomy wire 414 snares thrombus T, as shown in
It should be noted that the method steps described in
Inner sheath 434 is initially provided in a distalmost position that covers blood intake port 432 in a closed state, as shown in
Retrograde blood flow in vessel V is induced by placing venous return catheter 52 of
If antegrade flow is desired, inner sheath 434 may be retracted proximally to expose blood intake port 432, as shown in
Cerebral flow manipulation may be enhanced by placing a first catheter in accordance with
Catheters 450 and 470 each comprises a plurality of lumens. Inner sheaths 456 and 476 are configured to slide longitudinally within an outermost lumen of their respective catheters. Inner sheaths 456 and 476 communicate with deployment knobs 452 and 472. Sliding deployment knobs 452 and 472 within slots 454 and 474 controls movement of inner sheaths 456 and 476, respectively.
Inflation ports 462 and 482 communicate with lumens of their respective catheters. Working lumens 458, 460, 478 and 480 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 tubing 459 and 461 enable fluid communication between retrograde flow controller 465 and lumens of catheter 450 and 470, respectively. Retrograde flow controller 465 further communicates with venous return line 52 of
The apparatus described in
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).
Similarly, a second catheter 520 comprising occlusive element 522 and blood intake port 524 is disposed in the left and/or right vertebral artery VA. In this example, one catheter is shown. Inner sheath 526 is provided in a distalmost position to prevent fluid from entering intake port 544, and occlusive element 522 is deployed to occlude antegrade flow.
Venous return line 52 of
At this time, any of the flow control devices described in
The retrograde flow from catheters 500 and 520 encourages blood flowing in the middle cerebral artery MCA to flow toward both catheters, as indicated by the arrows in
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 when switch 467 of
It should be appreciated that varying the settings of retrograde flow controller 465 and deployable knobs 452 and 472 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 in
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.