The present disclosure relates generally to medical methods and devices. More particularly, the present disclosure relates to methods, system, and devices for accessing and treating vasculature such as carotid arterial vasculature and optionally establishing retrograde blood flow during performance of carotid artery stenting and other procedures.
The present disclosure also relates to methods and systems for accessing and treating the cerebral arterial vasculature such as for the treatment of stroke, Intracranial Atherosclerotic Disease (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, ruptured and unruptured intra- and extra-cranial aneurysm embolization, chronic occlusions, and other disease conditions of the neurovasculature.
The disclosed systems and methods establish and facilitate retrograde or reverse flow blood circulation such as for example in the region of the carotid artery bifurcation such as to limit or prevent the release of emboli into the cerebral vasculature, such as into the internal carotid artery.
In one aspect, there is disclosed a system for use in accessing and treating a carotid artery, the system comprising: an arterial access device adapted to be introduced into a common carotid artery via a percutaneous access location in a groin of a patient and receive blood flow from the common carotid artery via a distal region of the arterial access device, wherein the arterial access device includes a distal sheath which enters the common carotid artery; a shunt fluidly connected to the arterial access device, wherein the shunt comprises tubing defining a blood flow pathway for blood to flow from the arterial access device to a return site; and a flow control assembly coupled to the shunt and adapted to assist blood flow through the shunt, the flow control assembly including a pump having at least one roller that interacts with the tubing of the shunt to pump blood through the shunt toward the return site.
In another aspect, there is disclosed a method of treating a carotid artery, comprising: percutaneously accessing a femoral artery by inserting an arterial access device into the femoral artery through a puncture in the femoral artery, the arterial access device comprises a distal sheath; introducing the distal sheath into a common carotid artery via an aortic arch; expanding a balloon on the distal sheath to occlude at least a portion of the common carotid artery to cause blood to flow in a retrograde direction from an internal carotid artery into the distal sheath; shunting blood from the sheath to a return site via a shunt fluidly coupled to the distal sheath; and assisting blood flow through the shunt using a pump having at least one roller that interacts with a tubing of the shunt to pump blood through the shunt toward the return site.
Other features and advantages should be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosure.
The disclosed systems and methods establish and facilitate retrograde or reverse flow blood circulation such as for example in the region of the carotid artery bifurcation such as to limit or prevent the release of emboli into the cerebral vasculature, such as into the internal carotid artery. In non-limiting examples, the methods are useful for interventional procedures, such as stenting and angioplasty, atherectomy, performed through a transfemoral access approach into the common carotid artery, either using an open surgical technique or using a percutaneous technique, such as a modified Seldinger technique or a micropuncture technique. Any of a wide variety of interventions can be performed in conjunction with the systems and method described herein including the treatment of stroke or other condition, Intracranial Atherosclerotic Disease (ICAD), transient ischemic attack (TIA), acute ischemic stroke (AIS), tandem lesions, ruptured and unruptured intra- and extra-cranial aneurysm embolization, chronic occlusions, Intravascular Lithotripsy (IVL), Shockwave Intravascular Lithotripsy (IVL), embolization, and other disease conditions of the neurovasculature or vasculature in general.
Access to the common carotid artery is established by placing an access sheath or other tubular access cannula into a lumen of an artery (such as the femoral artery) at an access location. The access location is primarily described herein as the femoral artery although other access locations are possible including the neck (such as via the common carotid artery), transradial access, transaxillary access (including radial and brachial access.) The artery can be accessed at the access location via a percutaneous access or via a surgical cut down.
A distal end or region of the sheath, catheter, or other elongated body is routed through the vasculature and positioned in communication with the common carotid artery such as proximal to the junction or bifurcation B from the common carotid artery to the internal and external carotid arteries. The distal region can be positioned within the common carotid artery or in communication with the common carotid artery. A percutaneous version of the sheath may have an occlusion member at the distal end, for example a compliant occlusion balloon or other component. A catheter or guidewire with an occlusion member, such as a balloon, may be placed through the access sheath and positioned in the proximal external carotid artery ECA to inhibit the entry of emboli, but occlusion of the external carotid artery is not necessary. A second return sheath is placed in the venous system, for example the internal jugular vein IJV or femoral vein FV. The arterial access and venous return sheaths are connected to create an external arterial-venous shunt. The balloon can include a radiopaque material for visualization. The balloon can also be at least partially covered by a sheath, collar or other element that can protect the balloon during percutaneous entry and that can be peeled away after use.
Retrograde flow at least in the carotid artery region is established and may be modulated. Flow through the common carotid artery is occluded, such as by using an internal occlusion member such as a balloon, or other type of occlusion means. When flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system (or other location) causes blood to flow in a retrograde or reverse direction from the cerebral vasculature through the internal carotid artery and through the shunt into the venous system. In an alternate implementation, a vascular clamp can also be used via a surgical incision.
Alternately, the venous sheath can be eliminated and the arterial sheath is connected to an external collection reservoir or receptacle. The reverse flow can be collected in this receptacle. If desired, the collected blood can be filtered and subsequently returned to the patient during or at the end of the procedure. The pressure of the receptacle can be open to atmospheric pressure, causing the pressure gradient to create blood to flow in a reverse direction from the cerebral vasculature to the receptacle or the pressure of the receptacle could be a negative pressure.
Optionally, to achieve or enhance reverse flow from the internal carotid artery, flow from the external carotid artery may be blocked, such as by deploying a balloon or other occlusion element in the external carotid just above (i.e., distal) the bifurcation within the internal carotid artery.
Although the procedures and protocols are described herein in the context of carotid stenting, it will be appreciated that the methods for accessing the carotid artery described herein can also be useful for angioplasty, atherectomy, and any other interventional procedures which might be carried out in the carotid arterial system, such as at a location near the bifurcation between the internal and external carotid arteries. In addition, it will be appreciated that some of these access, vascular closure, and embolic protection methods will be applicable in other vascular interventional procedures, for example the treatment of acute stroke. The systems and methods described herein can also be used pursuant to a pulmonary procedure, a contrast removal procedure, peripheral atherectomy, transcatheter aortic valve replacement (TAVR), and thoracic endovascular aortic repair (TEVAR).
The present disclosure includes aspects for improving the performance of carotid artery access protocols. At least some of these aspects can be performed individually or in combination with one or more other of the improvements in order to facilitate and enhance the performance of the particular interventions in the carotid arterial system.
The system 100 interacts with the carotid artery to provide retrograde flow from the carotid artery to a venous return site, such as the internal jugular vein (or to another return site such as another large vein or an external receptacle in alternate implementations.) As described in more detail below, the retrograde flow system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120 that provides a passageway for retrograde flow from the arterial access device 110 to the venous return device 115.
A flow control assembly 125 interacts with the shunt 120. The flow control assembly 125 is adapted to regulate and/or monitor the retrograde flow from the common carotid artery to the internal jugular vein, as described in more detail below. The flow control assembly 125 interacts with the flow pathway through the shunt 120, either external to the flow path, inside the flow path, or both. The arterial access device 110 provides direct or indirect access to the common carotid artery such as by at least partially inserting into the common carotid artery CCA via the access location. The arterial access device in an implementation has may a flared proximal end such as just adjacent to a hub of the arterial access device.
The venous return device 115 at least partially inserts into a venous return site such as the internal femoral vein FV. The arterial access device 110 and the venous return device 115 couple to the shunt 120 at connection locations 127a and 127b. When flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system causes blood to flow in a retrograde or reverse direction RG (
In an implementation, transfemoral access to the common carotid artery is achieved percutaneously via an incision or puncture in the skin in the region of the femoral artery through which the arterial access device 110 is inserted. If an incision is used, then the incision can be about 0.5 cm in length in a non-limiting example. An occlusion element, such as an expandable balloon, can be used to occlude the common carotid artery CCA at a location proximal of the distal end of the arterial access device 110. The occlusion element can be located on the arterial access device 110 or it can be located on a separate device.
In another implementation, the arterial access device 110 accesses the common carotid artery CCA via a percutaneous transcarotid approach with an access location in the neck region of a patient. Transcarotid access provides a short length and non-tortuous pathway from the vascular access point to the target treatment site. For a transcarotid approach, an arterial distance from the arteriotomy to the target treatment site (as measured traveling through the artery) is 15 cm or less. In an implementation, the distance is between 5 and 10 cm. In an alternate implementation, the arterial access device 110 accesses the common carotid artery CCA via a direct surgical transcarotid approach. In the surgical approach, the common carotid artery can be occluded using a tourniquet 2105.
With reference to the enlarged view of the carotid artery in
The Circle of Willis CW is the main arterial anastomatic trunk of the brain where all major arteries which supply the brain, namely the two internal carotid arteries (ICAs) and the vertebral basilar system, connect. The blood is carried from the Circle of Willis by the anterior, middle and posterior cerebral arteries to the brain. This communication between arteries makes collateral circulation through the brain possible. Blood flow through alternate routes is made possible thereby providing a safety mechanism in case of blockage to one or more vessels providing blood to the brain. The brain can continue receiving adequate blood supply in most instances even when there is a blockage somewhere in the arterial system (e.g., when the ICA is ligated as described herein). Flow through the Circle of Willis ensures adequate cerebral blood flow by numerous pathways that redistribute blood to the deprived side.
The collateral potential of the Circle of Willis is believed to be dependent on the presence and size of its component vessels. It should be appreciated that considerable anatomic variation between individuals can exist in these vessels and that many of the involved vessels may be diseased. For example, some people lack one of the communicating arteries. If a blockage develops in such people, collateral circulation is compromised resulting in an ischemic event and potentially brain damage. In addition, an autoregulatory response to decreased perfusion pressure can include enlargement of the collateral arteries, such as the communicating arteries, in the Circle of Willis. An adjustment time is occasionally required for this compensation mechanism before collateral circulation can reach a level that supports normal function. This autoregulatory response can occur over the space of 15 to 30 seconds and can only compensate within a certain range of pressure and flow drop. Thus, it is possible for a transient ischemic attack to occur during the adjustment period. Very high retrograde flow rate for an extended period of time can lead to conditions where the patient's brain is not getting enough blood flow, leading to patient intolerance as exhibited by neurologic symptoms or in some cases a transient ischemic attack.
Anteriorly, the Circle of Willis is formed by the anterior cerebral arteries ACA and the anterior communicating artery ACoA which connects the two ACAs. The two posterior communicating arteries PCoA connect the Circle of Willis to the two posterior cerebral arteries PCA, which branch from the basilar artery BA and complete the Circle posteriorly.
The common carotid artery CCA also gives rise to external carotid artery ECA, which branches extensively to supply most of the structures of the head except the brain and the contents of the orbit. The ECA also helps supply structures in the neck and face. The common carotid arteries are encased on each side in a layer of fascia called the carotid sheath. This sheath also envelops the internal jugular vein and the vagus nerve. Anterior to the sheath is the sternocleidomastoideole. Transcarotid access to the common carotid artery and internal jugular vein, either percutaneous or surgical, can be made immediately superior to the clavicle, between the two heads of the sternocleidomastoid muscle and through the carotid sheath, with care taken to avoid the vagus nerve.
The common carotid artery bifurcates into the internal and external carotid arteries. The internal carotid artery continues upward without branching until it enters the skull to supply blood to the retina and brain. The external carotid artery branches to supply blood to the scalp, facial, ocular, and other superficial structures. Intertwined both anterior and posterior to the arteries are several facial and cranial nerves. Additional neck muscles may also overlay the bifurcation. These nerve and muscle structures can be dissected and pushed aside to access the carotid bifurcation during a carotid endarterectomy procedure. In some cases the carotid bifurcation is closer to the level of the mandible, where access is more challenging and with less room available to separate it from the various nerves which should be spared.
As discussed, the retrograde flow system 100 includes the arterial access device 110, venous return device 115, and shunt 120 which provides a passageway for retrograde flow from the arterial access device 110 to the venous return device 115. The system also includes the flow control assembly 125, which interacts with the shunt 120 to regulate and/or monitor retrograde blood flow through the shunt 120. Example implementations of the components of the retrograde flow system 100 are now described.
The distal sheath 605 is adapted to be introduced through a percutaneous incision or puncture in a wall of an artery (such as the femoral artery in the area of the groin). The distal sheath is positioned up the aortic arch AA into the target common carotid artery CCA. The sheath can vary in size and can be for example an 8 French sheath.
The distal sheath 605 can have a stepped or other configuration having a reduced diameter distal region 630 that forms one or more steps or gradual transitions along the length of the distal sheath, as shown in
At least a portion of the arterial access device and/or the dilator 645 can be pre-shaped in any of a variety of shapes to facilitate navigation through the blood vessel. For example,
The arterial access device 110 can be formed of a layered outer wall wherein each layer has a predetermined flexibility/stiffness. In an implementation shown in
The arterial access device can include a blood flow, blood pressure, or blood flow velocity measuring component to measure and provide an indication to a user of such features. In a method of use, patient blood pressure is increased during a procedure to increase blood flow rate through the shunt. The system can also be configured to shut off or slow down reverse flow (such as by shutting off or slowing down a pump) if blood pressure falls below a threshold value.
The arterial access device 110 can include one or more portions that include colors or other visual indications to provide a user with an indication of a purpose or functionality of a portion of the arterial access device 110, such as a port. For example, a particular color can indicate that a port connects to a main lumen, an aspiration lumen, or a shunt lumen of the arterial access device. Or another color can coincide with a pump access port for example. Other colors on the arterial access device can indicate a specification of the distal sheath 605, such an inner diameter, outer diameter, stiffness and/or flexibility 125.
With reference again to
A flush line 635 can be connected to the side of the hemostasis valve 625 and can have a stopcock 640 at its proximal or remote end. The flush-line 635 allows for the introduction of saline, contrast fluid, or the like, during the procedures. The flush line 635 can also allow pressure monitoring during the procedure. An elongated body such as a dilator 645 or other elongated body having a tapered distal end 650 can be provided to facilitate introduction of the distal sheath 605 into the artery or passage of the distal sheath 605 through the blood vessels. The dilator 645 can be introduced through the hemostasis valve 625 so that the tapered distal end 650 extends through the distal end of the sheath 605, as best seen in
The arterial access device can include or be coupled to a depth indicator that provide a visual indication of a depth of the device when inserted into an artery. The depth indicator, such as a collar on the arterial access device, can lock onto a portion of the arterial access device.
Optionally, a sheath stopper 705 such as in the form of a tube may be provided which is coaxially received over the exterior of the distal sheath 605, also as seen in
In an implementation, the balloon is an elastomeric balloon which is closely received over the exterior of the distal end of the sheath prior to inflation. When inflated, the elastomeric balloon can expand and conform to the inner wall of the common carotid artery (or other artery where it is positioned). In an implementation, the elastomeric balloon is able to expand to a diameter at least twice that of the non-deployed configuration, frequently being able to be deployed to a diameter at least three times that of the undeployed configuration, more preferably being at least four times that of the undeployed configuration, or larger.
As shown in
Another arterial access device is shown in
The sheath has a Y-adaptor 660 that connects the distal portion of the sheath to the proximal extension 610. The Y-adapter can also include a valve 670 that can be operated to open and close fluid connection to a connector or hub 680 that can be removably connected to a flow line such as a shunt. The valve 670 is positioned immediately adjacent to an internal lumen of the adapter 660, which communicates with the internal lumen of the sheath body 605.
The stopcock 640 can vary in size. In an implementation, the stopcock 640 has an internal lumen of about 0.200 inch although the size can vary. The stopcock or the sheath can be configured to achieve laminar blood flow therethrough. A stopcock as such can be positioned at one or more locations along the shunt such as for example between the arterial access device and the flow controller, and/or between the flow controller and venous return device.
With reference again to
During use, a user can visually track the location of the sheath 110 and the dilator 3920 as they are positioned into the artery. The sheath 110 and the dilator 3920 are both radiopaque such that they can be visualized via fluoroscopy. A first optical marker is located on a proximal end region of the dilator 3920. When the first optical marker is aligned with a landmark of the sheath 110, such as the proximal end of the RHV 3910, such alignment between the optical marker and the landmark on the sheath is an indication that the dilator's distalmost tapered region is fully extending from a distal tip of the sheath 110 such that the beginning of the taper is located at the distal tip of the sheath. That is, the alignment indicates to a user that the location 4105 (
This can be an important alignment position such that there is no gap present between the outer diameter of the dilator and the inner diameter of the sheath. If the dilator is shifted proximally or distally from this position, a gap will be present between the sheath and dilator which may cause potential for vessel damage or disease embolization during tracking.
With reference again to
During a carotid artery revascularization procedure, the arterial sheath 605 can be inserted into the common carotid artery (CCA) of the patient such as via a transfemoral approach wherein an access location for the sheath is located at the transfemoral artery. As described elsewhere herein, to achieve reverse flow of blood, the CCA may be occluded (such as using an expandable balloon as described below) to stop antegrade blood flow from the aorta through the CCA. Flow through the CCA can be occluded with an internal occlusion member such as a balloon, or other type of occlusion means. When flow through CCA is blocked, the natural pressure gradient between the internal carotid artery (ICA) and the venous system will cause blood to flow in a retrograde or reverse direction from the cerebral vasculature. Blood from the ICA and the external carotid artery (ECA) flows in a retrograde direction and the systems described herein allow the retrograde blood to flow into the sheath 605, through the flow controller 1130, the venous sheath 910, and then returned into the patient's femoral vein as described elsewhere herein. Loose embolic material can be carried with the retrograde blood flow into the arterial sheath 605.
As discussed, an expandable occlusion element 129, such as a balloon 129, is located on a distal region of the sheath 605.
In the region of the sheath 605 between the distal weld location and the proximal tack weld location, the outer jacket and inner layer of the sheath are not fixedly attached such that an annular balloon inflation lumen is formed therebetween for inflation of the balloon 129. Such an inflation lumen is interrupted by the tack weld such that one or more lumens are needed through the tack weld for inflation of the lumen.
With reference again to
In an implementation, the dilator 3920 has a consistent durometer along a portion of its length such as along a majority of its length with a variation in flexibility in a distal region of the dilator. This is represented in
In another implementation represented in
Referring now to
An alternate configuration is shown in
The shunt 120 can be formed of a single tube or multiple, connected tubes that provide fluid communication between the arterial access device 110 and the venous return catheter 115 to provide a pathway for retrograde blood flow therebetween. As shown in
In an implementation, the shunt 120 can be formed of at least one tube that communicates with the flow control assembly 125. The shunt 120 can be any structure that provides a fluid pathway for blood flow. The shunt 120 can have a single lumen or it can have multiple lumens. The shunt 120 can be removably attached to the flow control assembly 125, arterial access device 110, and/or venous return device 115. Prior to use, the user can select a shunt 120 with a length that is most appropriate for use with the arterial access location and venous return location.
In an implementation, the shunt 120 can include one or more extension tubes that can be used to vary the length of the shunt 120. The extension tubes can be modularly attached to the shunt 120 to achieve a desired length. The modular aspect of the shunt 120 permits the user to lengthen the shunt 120 as needed depending on the site of venous return.
As mentioned, the length of the shunt can be adjusted. In an implementation, connectors between the shunt and the arterial and/or venous access devices are configured to minimize flow resistance. In an implementation, the arterial access sheath 110, the retrograde shunt 120, and the venous return sheath 115 are combined to create a low flow resistance arterio-venous AV shunt, as shown in
Actual flow through the AV shunt when in use will further depend on the cerebral blood pressures and flow resistances of the patient. In an implementation, the system is configured to detect blood pressure and control blood flow based on blood pressure such as by shutting down or reducing pressure of a pump connected to the system.
The flow control assembly 125 interacts with the retrograde shunt 120 to regulate and/or monitor the retrograde flow rate from the common carotid artery to the venous return site, such as the femoral vein, internal jugular vein, or to the external receptacle 130. In this regard, the flow control assembly 125 enables the user to achieve higher maximum flow rates than existing systems and to also selectively adjust, set, or otherwise modulate the retrograde flow rate. Various mechanisms can be used to regulate the retrograde flow rate. The flow control assembly 125 enables the user to configure retrograde blood flow in a manner that is suited for various treatment regimens, as described below.
In addition, the flow control assembly 125 can include one or more flow sensors 1135 and/or anatomical data sensors 1140 for sensing one or more aspects of the retrograde flow. A filter 1145 can be positioned along the shunt 120 for removing emboli before the blood is returned to the venous return site. When the filter 1145 is positioned upstream of the controller 1130, the filter 1145 can prevent emboli from entering the controller 1145 and potentially clogging the variable flow resistance component 1125. It should be appreciated that the various components of the flow control assembly 125 (including pump 1110, valves 1115, syringes 1120, variable resistance component 1125, sensors 1135/1140, and filter 1145) can be positioned at various locations along the shunt 120 and at various upstream or downstream locations relative to one another. The components of the flow control assembly 125 are not limited to the locations shown in
The flow control assembly 125 can vary in configuration. In an implementation, the flow control assembly includes a housing that is shaped to ergonomically interact with the patient's anatomy. For example,
In an implementation, the filter 1145 includes two or more filters positioned in a layered arrangement along the blood flow pathway of the shunt. For example, as schematically shown in
Both the variable resistance component 1125 and the pump 1110 can be coupled to the shunt 120 to control the retrograde flow rate. The variable resistance component 1125 controls the flow resistance, while the pump 1110 provides for positive displacement of the blood through the shunt 120. Thus, the pump can be activated to drive the retrograde flow rather than relying on the perfusion stump pressures of the ECA and ICA and the venous back pressure to drive the retrograde flow. The pump 1110 can be a peristaltic tube pump or any type of pump including a positive displacement pump. The pump 1110 can be activated and deactivated (either manually or automatically via the controller 1130) to selectively achieve blood displacement through the shunt 120 and to control the flow rate through the shunt 120. Displacement of the blood through the shunt 120 can also be achieved in other manners including using the aspiration syringe 1120, or a suction source such as a vacutainer, vaculock syringe, or wall suction may be used. The pump 1110 can communicate with the controller 1130.
One or more flow control valves 1115 can be positioned along the pathway of the shunt. The valve(s) can be manually actuated or automatically actuated (via the controller 1130). The flow control valves 1115 can be, for example one-way valves to prevent flow in the antegrade direction in the shunt 120, check valves, or high pressure valves which would close off the shunt 120, for example during high-pressure contrast injections (which are intended to enter the arterial vasculature in an antegrade direction.
In an implementation of a shunt with both a filter 1145 and a one-way check valve 1115, the check valve is located downstream of the filter. In this manner, if there is debris traveling in the shunt, it is trapped in the filter before it reaches the check valve. Many check valve configurations include a sealing member that seals against a housing that contains a flow lumen.
The controller 1130 communicates with components of the system 100 including the flow control assembly 125 to enable manual and/or automatic regulation and/or monitoring of the retrograde flow through the components of the system 100 (including, for example, the shunt 120, the arterial access device 110, the venous return device 115 and the flow control assembly 125). For example, a user can actuate one or more actuators on the controller 1130 to manually control the components of the flow control assembly 125. Manual controls can include switches or dials or similar components located directly on the controller 1130 or components located remote from the controller 1130 such as a foot pedal or similar device. The controller 1130 can also automatically control the components of the system 100 without requiring input from the user. In an implementation, the user can program software in the controller 1130 to enable such automatic control. The controller 1130 can control actuation of the mechanical portions of the flow control assembly 125. The controller 1130 can include circuitry or programming that interprets signals generated by sensors 1135/1140 such that the controller 1130 can control actuation of the flow control assembly 125 in response to such signals generated by the sensors.
The representation of the controller 1130 in
The controller 1130 can include one or more indicators that provides a visual and/or audio signal to the user regarding the state of the retrograde flow. An audio indication advantageously reminds the user of a flow state without requiring the user to visually check the flow controller 1130. The indicator(s) can include a speaker 1150 and/or a light 1155 or any other means for communicating the state of retrograde flow to the user. The controller 1130 can communicate with one or more sensors of the system to control activation of the indicator. Or activation of the indicator can be tied directly to the user actuating one of the flow control actuators 1165. The indicator need not be a speaker or a light. The indicator could simply be a button or switch that visually indicates the state of the retrograde flow. For example, the button being in a certain state (such as a pressed or down state) may be a visual indication that the retrograde flow is in a high state. Or a switch or dial pointing toward a particular labeled flow state may be a visual indication that the retrograde flow is in the labeled state.
The system can include an indicator to indicate to a user that blood flow has been stopped through the shunt or occluded in an artery.
The controller 1130 can include one or more actuators that the user can press, switch, manipulate, or otherwise actuate to regulate the retrograde flow rate and/or to monitor the flow rate. For example, the controller 1130 can include a flow control actuator 1165 (such as one or more buttons, knobs, dials, switches, etc.) that the user can actuate to cause the controller to selectively vary an aspect of the reverse flow. For example, in the illustrated implementation, the flow control actuator 1165 is a knob that can be turned to various discrete positions each of which corresponds to the controller 1130 causing the system 100 to achieve a particular retrograde flow state. The states include, for example, (a) OFF; (b) LO-FLOW; (c) HI-FLOW; and (d) ASPIRATE. It should be appreciated that the foregoing states are merely exemplary and that different states or combinations of states can be used. The controller 1130 achieves the various retrograde flow states by interacting with one or more components of the system, including the sensor(s), valve(s), variable resistance component, and/or pump(s). It should be appreciated that the controller 1130 can also include circuitry and software that regulates the retrograde flow rate and/or monitors the flow rate such that the user wouldn't need to actively actuate the controller 1130.
The OFF state corresponds to a state where there is no retrograde blood flow through the shunt 120. When the user sets the flow control actuator 1165 to OFF, the controller 1130 causes the retrograde flow to cease, such as by shutting off valves or closing a stop cock in the shunt 120. The LO-FLOW and HI-FLOW states correspond to a low retrograde flow rate and a high retrograde flow rate, respectively. When the user sets the flow control actuator 1165 to LO-FLOW or HI-FLOW, the controller 1130 interacts with components of the flow control regulator 125 including pump(s) 1110, valve(s) 1115 and/or variable resistance component 1125 to increase or decrease the flow rate accordingly. Finally, the ASPIRATE state corresponds to opening the circuit to a suction source, for example a vacutainer or suction unit, if active retrograde flow is desired.
The system can be used to vary the blood flow between various states including an active state, a passive state, an aspiration state, and an off state. The active state corresponds to the system using a means that actively drives retrograde blood flow. Such active means can include, for example, a pump, syringe, vacuum source, etc. The passive state corresponds to when retrograde blood flow is driven by the perfusion stump pressures of the ECA and ICA and possibly the venous pressure. The aspiration state corresponds to the system using a suction source, for example a vacutainer or suction unit, to drive retrograde blood flow. The off state corresponds to the system having zero or near zero retrograde blood flow such as the result of closing a stopcock or valve. The low and high flow rates can be either passive or active flow states. In an implementation, the particular value (such as in ml/min) of either the low flow rate and/or the high flow rate can be predetermined and/or pre-programmed into the controller such that the user does not actually set or input the value. Rather, the user simply selects “high flow” and/or “low flow” (such as by pressing an actuator such as a button on the controller 1130) and the controller 1130 interacts with one or more of the components of the flow control assembly 125 to cause the flow rate to achieve the predetermined high or low flow rate value. In another implementation, the user sets or inputs a value for low flow rate and/or high flow rate such as into the controller. In another implementation, the low flow rate and/or high flow rate is not actually set. Rather, external data (such as data from the anatomical data sensor 1140) is used as the basis for affects the flow rate.
The flow control actuator 1165 can be multiple actuators, for example one actuator, such as a button or switch, to switch state from LO-FLOW to HI-FLOW and another to close the flow loop to OFF, for example during a contrast injection where the contrast is directed antegrade into the carotid artery. In an implementation, the flow control actuator 1165 can include multiple actuators. For example, one actuator can be operated to switch flow rate from low to high, another actuator can be operated to temporarily stop flow, and a third actuator (such as a stopcock) can be operated for aspiration using a syringe. In another example, one actuator is operated to switch to LO-FLOW and another actuator is operated to switch to HI-FLOW. Or, the flow control actuator 1165 can include multiple actuators to switch states from LO-FLOW to HI-FLOW and additional actuators for fine-tuning flow rate within the high flow state and low flow state. Upon switching between LO-FLOW and HI-FLOW, these additional actuators can be used to fine-tune the flow rates within those states. Thus, it should be appreciated that within each state (i.e. high flow state and low flow states) a variety of flow rates can be dialed in and fine-tuned. A wide variety of actuators can be used to achieve control over the state of flow.
The controller 1130 or individual components of the controller 1130 can be located at various positions relative to the patient and/or relative to the other components of the system 100. For example, the flow control actuator 1165 can be located near the hemostasis valve where any interventional tools are introduced into the patient in order to facilitate access to the flow control actuator 1165 during introduction of the tools. The location may vary, for example, based on whether a transfemoral or a transcarotid approach is used. The controller 1130 can have a wireless connection to the remainder of the system 100 and/or a wired connection of adjustable length to permit remote control of the system 100. The controller 1130 can have a wireless connection with the flow control regulator 125 and/or a wired connection of adjustable length to permit remote control of the flow control regulator 125. The controller 1130 can also be integrated in the flow control regulator 125. Where the controller 1130 is mechanically connected to the components of the flow control assembly 125, a tether with mechanical actuation capabilities can connect the controller 1130 to one or more of the components. In an implementation, the controller 1130 can be positioned a sufficient distance from the system 100 to permit positioning the controller 1130 outside of a radiation field when fluoroscopy is in use.
The controller 1130 and any of its components can interact with other components of the system (such as the pump(s), sensor(s), shunt, etc) in various manners. For example, any of a variety of mechanical connections can be used to enable communication between the controller 1130 and the system components. Alternately, the controller 1130 can communicate electronically or magnetically with the system components. Electro-mechanical connections can also be used. The controller 1130 can be equipped with control software that enables the controller to implement control functions with the system components. The controller itself can be a mechanical, electrical or electro-mechanical device. The controller can be mechanically, pneumatically, or hydraulically actuated or electromechanically actuated (for example in the case of solenoid actuation of flow control state). The controller 1130 can include a computer, computer processor, and memory, as well as data storage capabilities.
In an implementation, the connectors which connect the elements of the reverse flow system are large bore, quick-connect style connectors. For example, a male large-bore hub 680 on the Y-adaptor 660 of arterial sheath 110 connects to a female counterpart on the arterial side of flow shunt 120. The connections can be standard female and male Luer connectors or other style of tubing connectors.
As mentioned, the flow control assembly 125 can include or interact with one or more sensors, which communicate with the system 100 and/or communicate with the patient's anatomy. Each of the sensors can be adapted to respond to a physical stimulus (including, for example, heat, light, sound, pressure, magnetism, motion, etc.) and to transmit a resulting signal for measurement or display or for operating the controller 1130. In an implementation, the flow sensor 1135 interacts with the shunt 120 or the arterial access device to sense an aspect of the flow through the shunt 120, such as flow velocity or volumetric rate of blood flow. The flow sensor 1135 could be directly coupled to a display that directly displays the value of the volumetric flow rate or the flow velocity. Or the flow sensor 1135 could feed data to the controller 1130 for display of the volumetric flow rate or the flow velocity.
The type of flow sensor 1135 can vary. The flow sensor 1135 can be a mechanical device, such as a paddle wheel, flapper valve, rolling ball, or any mechanical component that responds to the flow through the shunt 120. Movement of the mechanical device in response to flow through the shunt 120 can serve as a visual indication of fluid flow and can also be calibrated to a scale as a visual indication of fluid flow rate. The mechanical device can be coupled to an electrical component. For example, a paddle wheel can be positioned in the shunt 120 such that fluid flow causes the paddle wheel to rotate, with greater rate of fluid flow causing a greater speed of rotation of the paddle wheel. The paddle wheel can be coupled magnetically to a Hall-effect sensor to detect the speed of rotation, which is indicative of the fluid flow rate through the shunt 120.
The system 100 is not limited to using a flow sensor 1135 that is positioned in the shunt 120 or a sensor that interacts with the venous return device 115 or the arterial access device 110. For example, an anatomical data sensor 1140 can communicate with or otherwise interact with the patient's anatomy such as the patient's neurological anatomy. In this manner, the anatomical data sensor 1140 can sense a measurable anatomical aspect that is directly or indirectly related to the rate of retrograde flow from the carotid artery. For example, the anatomical data sensor 1140 can measure blood flow conditions in the brain, for example the flow velocity in the middle cerebral artery, and communicate such conditions to a display and/or to the controller 1130 for adjustment of the retrograde flow rate based on predetermined criteria. In an implementation, the anatomical data sensor 1140 comprises a transcranial Doppler ultrasonography (TCD), which is an ultrasound test that uses reflected sound waves to evaluate blood as it flows through the brain. Use of TCD results in a TCD signal that can be communicated to the controller 1130 for controlling the retrograde flow rate to achieve or maintain a desired TCD profile. The anatomical data sensor 1140 can be based on any physiological measurement, including reverse flow rate, blood flow through the middle cerebral artery, TCD signals of embolic particles, or other neuromonitoring signals.
Flow through the carotid artery bifurcation at different stages of the methods of the present disclosure will be described. Initially, the distal sheath 605 (or any implementation of the percutaneous sheaths described herein) of the arterial access device 110 is introduced into the common carotid artery CCA. As mentioned, entry into the common carotid artery CCA can be via a transfemoral approach such as via an access location at the groin and can be either a direct surgical cut-down or percutaneous access. Or entry can be directly in the CCA. Furthermore, alternate entry locations are possible including a transradial location. After the sheath 605 of the arterial access device 110 has been introduced into direct or indirect communication with the common carotid artery CCA, the blood flow will continue in antegrade direction AG with flow from the common carotid artery entering both the internal carotid artery ICA and the external carotid artery ECA.
The venous return device 115 is then inserted into a venous return site, such as the internal jugular vein IJV or femoral vein or brachial vein or subclavian vein, which are non-limiting examples. The shunt 120 is used to connect the flow lines 615 and 915 of the arterial access device 110 and the venous return device 115, respectively (as shown in
Once all components of the system are in place and connected, flow through the common carotid artery CCA is stopped, such as by using an expandable occlusion element of the percutaneous sheath in the common carotid artery CCA. Alternately, the occlusion element 129 is introduced on second occlusion device 112 separate from the distal sheath 605 of the arterial access device 110. The ECA may also be occluded with a separate occlusion element, either on the same device 110 or on a separate occlusion device.
At that point retrograde flow RG from the external carotid artery ECA and internal carotid artery ICA will begin and will flow through the sheath 605, the flow line 615, the shunt 120, and into the venous return device 115 via the flow line 915. The flow control assembly125 regulates the retrograde flow as described above. While the retrograde flow is maintained, a stent delivery catheter (or other intervention device) is introduced into the sheath 605. The stent delivery catheter is introduced into the sheath 605 through the hemostasis valve 615 and the proximal extension 610. The stent delivery catheter is advanced into the internal carotid artery ICA and a stent 2115 deployed at the bifurcation B.
Optionally, while flow from the common carotid artery continues and the internal carotid artery remains blocked, measures can be taken to further loosen emboli from the treated region. For example, mechanical elements may be used to clean or remove loose or loosely attached plaque or other potentially embolic debris within the stent, thrombolytic or other fluid delivery catheters may be used to clean the area, or other procedures may be performed. For example, treatment of in-stent restenosis using balloons, atherectomy, or more stents can be performed under retrograde flow. In another example, the occlusion balloon catheter may include flow or aspiration lumens or channels which open proximal to the balloon. Saline, thrombolytics, or other fluids may be infused and/or blood and debris aspirated to or from the treated area without the need for an additional device. While the emboli thus released will flow into the external carotid artery, the external carotid artery is generally less sensitive to emboli release than the internal carotid artery. By prophylactically removing potential emboli which remain, when flow to the internal carotid artery is reestablished, the risk of emboli release is even further reduced. The emboli can also be released under retrograde flow so that the emboli flows through the shunt 120 to the venous system, a filter in the shunt 120, or the receptacle 130.
After the lesion has been treated (e.g., using a stent) and the bifurcation has been cleared of emboli, the occlusion element 129 or alternately the tourniquet 2105 can be released, reestablishing antegrade flow. The sheath 605 can then be removed.
A self-closing element may be deployed about the penetration in the wall of the entry location, such as the common carotid artery or femoral artery, prior to withdrawing the sheath 605 at the end of the procedure. The self-closing element can be deployed at or near the beginning of the procedure, but optionally, the self-closing element can be deployed as the sheath is being withdrawn, often being released from a distal end of the sheath onto the wall of the common carotid artery.
With reference still to
As shown in
In another implementation, the pump 1910 is a roller pump.
The tubing 2023 is flexible and can be coupled along its length to a pre-shaped structure 2207, such as a rigid structure, that causes the tubing 2023 to extend along a predetermined pathway with a predetermined shape such a, straight shape, a curved shape or a curvilinear shape in a region of the tubing that interacts with the rollers of the pump. The structure 2207 can extend along a portion of the tubing in a side-by-side relationship such that the flexible tubing 2203 conforms to the shape of the structure 2207 along the predetermined pathway. The roller mechanism 2025 rotates about an axis such that the rollers 2210 interact with the lumen of the tubing 2203 to pump blood through the lumen from the inlet 1915 toward the outlet 1920. Each roller 2210 is configured to rotate around a respective roller axis (which can be at the center point of each roller) so that each roller spins or rolls relative to the tubing when in contact with the tubing. Each roller can ride on a respective bushing to enable such rolling. Such action forms suction at the inlet 1915 and increased pressure at the outlet 1920. The rollers 2210 can be fully occlusive relative to the blood flow lumen. An electric motor can drive rotation of the roller mechanism 2025 and/or rollers. In another implementation shown in
With reference to
A pressure relief valve 2810 is positioned just past the pump 1910 in a flow direction and allows for blood flow to recirculate around the pump 1910 via the passive flow pathway 2805 such as where the pump 1910 is generating excessively high output pressures due to venous output blockage or a kink in a flow tubing 1830. The pressure relief valve opens at a predetermined pressure to redirect blood flow to the input of the pump 1910 in a situation where the outflow pressure increases beyond a set limit such as caused by occluded outflow. The pressure relief valve 2810 eliminates or reduces the situation where pressure is driven to unnecessarily high level.
The external flow circuit 1840 includes a vacuum flow resistor 3005, which is used in situations where the blood pressure near the arterial sheath is a strong vacuum and thus risks collapsing the artery. Implementations of the vacuum flow resistor 3005 are described in further detail below. The vacuum flow resistor 3005 collapses (to increase flow resistance) as a function of the pressure differential between the blood pressure in the shunt relative to atmosphere to reduce vacuum pressure experienced by the artery.
The external flow circuit 1840 includes at least one backflow preventer check valve 3015, which comprises a one-valve that prevents blood flow from inadvertently flowing from the flow circuit or vein back into the artery.
A high low switch 3020 is coupled to the pump 1910 and has a low flow setting a high flow setting. The external flow circuit 1840 further includes a stop switch 1925 (or on-off valve) that can be activated to temporarily stop blood flow through the system. A filter 1930 captures cloths and/or embolic debris. The serial order of components in the system may be modified or otherwise adjust performance.
As discussed above, the system can include a vacuum flow resistor 3005.
With reference again to
The flow resistance through the vacuum flow resistor 3005 increases as the pressure differential between the blood pressure Pi in the shunt and atmospheric pressure Patm increases. In
The second flow pathway 3710 includes an inlet valve 3715, an outlet valve 3720, and one or more secondary check valves. The inlet valve 3715 has a predetermined cracking pressure such as in the range of 1-3 psi (in a non-limiting example) to allow flow therethrough at high input pressure. At low input pressure, the pump 1910 utilizes only the first flow pathway 3705 as the inlet valve 3710 remains closed at such low pressure. The outlet valve 3720 has a relatively low cracking pressure configured to prevent backflow at low input pressure. At high input pressure, the pump 1910 utilizes both the first flow pathway 3705 and the second flow pathway 3710 as the inlet valve opens at such high pressure. The use of both the first flow pathway 3705 and the second flow pathway 3710 increases the pump efficiency. A desired efficiency, which can be predetermined and specifically tailored across a pressure input range can be controlled by adjusting the inlet valve cracking pressure and/or the size of the second flow pathway 3710 relative to the size of the first flow pathway 3705.
Various techniques and modalities can be used to image the vascular anatomy during a procedure such as those described herein. Such techniques include, for example, computed tomography (CT) scan, ultrasound, and other surrogate imaging modalities. These methods generally translate forms of energy into visible light to create a visible image, which can be limit in various aspects, including resolution, depth of focus, field of view, and perspective. One difficulty with using visible light to view vascular anatomy, disease, treatment, trauma, and other features is that blood is not transparent. An injected bolus of saline can be used to clear blood from the visual field, but the resulting view is temporary and items such as turbulent flow and mixed blood can obscure the resulting view. Further, a given procedure may be incompatible with such a technique. Thus, current methods for intravascular imaging provide limited visual information that can make it difficult to fully understand vascular anatomy, disease, treatments, and trauma.
In order to visualize the inside of the vessel using optical devices (such as fiber optic endoscopes, scanning fiber endoscopes, optical coherence tomography, etc.), blood is flushed from the vessel. Injecting a bolus of saline through a flush line of the arterial access device during a flow stasis state can displace the blood from a region of interest and allow visualization using optical methods. Such a method of clamping or occluding the vessel as described herein, injecting saline (or other clear fluid such as contrast), and imaging can be done at any point with various results.
For example, evaluating the vascular anatomy or disease prior to introducing a angioplasty balloon or stent system helps to determine the position and extent of the lesion, Imaging can also be used after angioplasty and after stenting to evaluate the vessel or lesion following treatments. Flow reversal can utilized after imaging to ensure any debris that is generated during imaging is filtered using the techniques described herein.
Although implementations of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, implementations, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the appended claims should not be limited to the description of the implementations contained herein.
This application claims priority to U.S. patent application No. 63/595,988 filed Nov. 3, 2023, and U.S. patent application No. 63/569,390 filed Mar. 25, 2024, the contents of which are hereby incorporated by reference herein in their entireties.
Number | Date | Country | |
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63569390 | Mar 2024 | US | |
63595988 | Nov 2023 | US |