Patent Application
20230012025
The present invention generally relates devices and methods for removing acute blockages from blood vessels during intravascular medical treatments.
Clot retrieval aspiration catheters and devices are used in mechanical thrombectomy for endovascular intervention, often in cases where patients are suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing the neurovascular bed in particular can be challenging because the target vessels are small in diameter, remote relative to the site of insertion, and highly tortuous.
In thrombectomy there is a tradeoff between deliverability of endovascular thrombectomy catheters and size of the device needed to capture the clot. Larger catheters are more difficult to deliver because they tend to be stiffer and less flexible. Clots are the same size or larger than a target vessel, thus catheters that are close to or the same size as the vessel are better able to capture the clot by complete ingestion. Further, once placed at a site, aspiration of a clot can cause blood vessels to collapse, preventing capture of the clot and potentially damaging the blood vessel.
Example systems and methods of treatment are presented herein which generally involve expanding a bracing frame within a blood vessel between a clot and an aspiration catheter, aspirating the clot through a passageway of the bracing frame, and supporting the blood vessel by the bracing frame as negative pressure is created by the aspiration. The bracing frame can thereby reduce likelihood of blood vessel collapse compared to a similar procedure which does not include the bracing frame. The bracing frame can be removed from the blood vessel during treatment. In some examples, the bracing frame can further function to expand a mouth of the catheter. In some examples, the system can include a stentriever. The stentriever is optional, can be delivered separately from the bracing frame in some examples, and can be delivered together with the bracing frame portion in some examples.
An example system configured to retrieve an obstruction from a blood vessel can include an aspiration catheter, a delivery catheter, and a tubular framework. The aspiration catheter can have a lumen sized to receive at least a portion of the obstruction therein. The aspiration catheter can be configured maintain an open flow path through the lumen of the aspiration catheter upon application of negative pressure due to aspiration through the lumen of the aspiration catheter. The delivery catheter can be sized to slide through the lumen of the aspiration catheter. The tubular framework can be collapsed within the delivery catheter. The tubular framework can be configured to expand to a deployed configuration within the blood vessel upon being expelled from the delivery catheter. In the deployed configuration the tubular framework can be configured to inhibiting radial collapse of the blood vessel due to the negative pressure in a negative pressure region of the blood vessel. In the deployed configuration the tubular framework can have a passageway therethrough sized to receive at least a portion of the obstruction therein.
The tubular framework can have a diameter of about 0.30 inches when collapsed within the delivery catheter.
The tubular framework can lack membrane cover. Alternatively, the tubular framework can include a membrane over a proximal portion of the tubular framework.
The aspiration catheter can have a malleable distal portion that is configured to expand in circumference upon expansion of a proximal portion of the tubular framework to the deployed configuration within the distal portion of the aspiration catheter.
The example system can further include a stentriever and a microcatheter configured to be delivered through the lumen of the aspiration catheter, through the passageway of the tubular framework while the tubular framework is in the deployed configuration, and across the obstruction. The stentriever can be configured to expand and engage the obstruction upon retraction of the microcatheter. At least a portion of the stentriever, when expanded, can be sized to enter the passageway of the tubular framework.
As an alternative, to the stentriever and microcatheter, the example system can include a clot retrieval device that includes the tubular framework and a stentriever portion. The clot retrieval device can include a bracing frame portion which includes the tubular framework and a collar. The stentriever portion can include an expandable framework and a pull wire. The collar of the bracing frame portion can circumscribe the pull wire. The clot retrieval device can be collapsed within the delivery catheter so that the tubular framework and stentriever can be delivered together. The bracing frame portion can further include a pull tube circumscribing the pull wire of the stentriever portion. The pull tube can be slidable over the pull wire to thereby move the expandable framework of the stentriever portion in relation to the tubular framework of the bracing frame portion. The pull wire can further include a radial extension that is positioned in a proximal direction in relation to the collar and that is configured to engage the collar of the bracing frame portion thereby inhibiting proximal movement of the bracing frame portion in relation to the stentriever portion.
A first example method of retrieving an obstruction from a blood vessel can include one or more of the follow steps executed in a variety of orders and combinations and including steps not described as understood by a person skilled in the pertinent art. A tubular framework can be expanded to a deployed configuration within the blood vessel such that in the deployed configuration at least a portion of the tubular framework is in contact with blood vessel walls in a proximal direction from the obstruction. An aspiration catheter can be positioned such that a mouth of the catheter is over a proximal portion of the tubular framework. A negative pressure region can be created within the blood vessel by aspirating through a lumen of the aspiration catheter while the tubular framework is in the deployed configuration. The blood vessel can be inhibited from collapsing radially in the negative pressure region by maintaining the tubular framework in the deployed configuration. At least a portion of the obstruction can be drawn into a lumen of the tubular framework by aspirating through the lumen of the aspiration catheter.
The first example method can further include sealing a membrane on the tubular framework to the blood vessel wall and to the mouth of the aspiration catheter.
The first example method can further include moving at least a portion of the tubular framework into the lumen of the aspiration catheter while at least a portion of the obstruction is within the lumen of the tubular framework.
The first example method can further include traversing the tubular framework and a bracing frame delivery catheter distally through the lumen of the aspiration catheter while the tubular framework is in a collapsed configuration within the bracing frame delivery catheter. The first example method can further include expelling the tubular framework from the bracing frame delivery catheter, thereby causing the tubular framework to move from the collapsed configuration to the deployed configuration.
The first example method can further include expanding a circumference of the mouth of the aspiration catheter when the tubular framework is expanded to the deployed configuration by providing a radially outward force from a proximal portion of the tubular framework against an inner wall of the lumen of the aspiration catheter approximate the mouth of the aspiration catheter.
The first example method can further include moving the mouth of the aspiration catheter distally over the proximal portion of the tubular framework while the tubular framework is in the deployed configuration to thereby expand the circumference of the mouth of the aspiration catheter.
The first example method can further include traversing a stentriever and a microcatheter distally through the lumen of the aspiration catheter, through the lumen of the tubular framework while the tubular framework is in the deployed configuration, and across the obstruction. The first example method can further include retracting the microcatheter, thereby causing the stentriever to expand across the obstruction. The first example method can further include pulling at least a portion of the stentriever and at least a portion of the obstruction within the lumen of the tubular framework while the tubular framework is in the deployed configuration.
The first example method can further include moving at least a portion of the tubular framework into the lumen of the aspiration catheter and at least a portion of the stentriever within the lumen of the aspiration catheter while at least a portion of the obstruction is within the lumen of the tubular framework.
The first example method can further include pulling a pull wire extending proximally from an expandable cage of the stentriever thereby pulling at least a portion of the stentriever and at least a portion of the obstruction within the lumen of the tubular framework. The first example method can further include engaging a radial extension of the pull wire to a collar of the tubular framework. The first example method can further include pulling the pull wire, thereby causing at least a portion of the tubular framework to move into the lumen of the aspiration catheter and at least a portion of the stentriever to move within the lumen of the aspiration catheter while at least a portion of the obstruction is within the lumen of the tubular framework.
The first example method can further include traversing a clot retrieval device and microcatheter through the lumen of the aspiration catheter while the clot retrieval device is in a collapsed configuration within the microcatheter. The clot retrieval device can include a bracing frame portion and a stentriever portion. The stentriever portion can include an expandable framework and a pull wire. The bracing frame portion can include the tubular framework and a collar. The collar can circumscribe the pull wire. The method can further include expelling the clot retrieval device from the microcatheter such that the expandable framework of the stentriever portion expands across the obstruction and the tubular framework expands to the deployed configuration.
The bracing frame portion can further include a pull tube circumscribing the pull wire of the stentriever portion. The first example method can further include sliding the pull tube in relation to the pull wire to thereby move the expandable framework of the stentriever portion in relation to the tubular framework of the bracing frame portion.
The first example method can further include engaging, to the collar of the bracing frame portion, a radial extension of the pull wire that is positioned in a proximal direction in relation to the collar, thereby inhibiting proximal movement of the bracing frame portion in relation to the stentriever portion.
A second example method of retrieving an obstruction from a blood vessel can include one or more of the following steps executed in a variety of orders and combinations and including steps not described as understood by a person skilled in the pertinent art. A tubular framework can be expanded to a deployed configuration within the blood vessel in a proximal direction in relation to the obstruction such that in the deployed configuration at least a portion of the tubular framework provides a radially outward force against blood vessel walls. A catheter can be positioned such that a mouth of the catheter is over a proximal portion of the tubular framework. A stentriever can be expanded across the obstruction. At least a portion of the stentriever and at least a portion of the obstruction can be pulled within a passageway through the tubular framework while the tubular framework is in the deployed configuration.
The second example method can further include sealing a membrane on the tubular framework to the blood vessel wall and to the mouth of the aspiration catheter.
The second example method can further include aspirating through a lumen of the catheter while the tubular framework is in the deployed configuration, thereby creating a negative pressure region within the blood vessel between the obstruction and the mouth of the catheter. The second example method can further include inhibiting radial collapse of the blood vessel in the negative pressure region by maintaining the tubular framework in the deployed configuration.
The second example method can further include moving at least a portion of the tubular framework into a lumen of the catheter and at least a portion of the stentriever within the lumen of the catheter while at least a portion of the obstruction is within the passageway through the tubular framework.
The second example method can further include pulling a pull wire extending proximally from an expandable cage of the stentriever thereby pulling at least a portion of the stentriever and at least a portion of the obstruction within the passageway through the tubular framework. The second example method can further include engaging a radial extension of the pull wire to a collar of the tubular framework. The second example method can further include pulling the pull wire, thereby causing at least a portion of the tubular framework to move into a lumen of the catheter and at least a portion of the stentriever to move within the lumen of the catheter while at least a portion of the obstruction is within the passageway through the tubular framework.
The second example method can further include traversing a clot retrieval device and microcatheter through a lumen of the catheter while the clot retrieval device is in a collapsed configuration within the microcatheter. The clot retrieval device can include a bracing frame portion and a stentriever portion. The stentriever portion can include an expandable framework and a pull wire. The bracing frame portion can include the tubular framework and a collar. The collar can circumscribe the pull wire. The second example method can further include expelling the clot retrieval device from the microcatheter such that the expandable framework of the stentriever portion expands across the obstruction and the tubular framework expands to the deployed configuration.
The bracing frame portion can further include a pull tube circumscribing the pull wire of the stentriever portion. The second example method can further include sliding the pull tube in relation to the pull wire to thereby move the expandable framework of the stentriever portion in relation to the tubular framework of the bracing frame portion.
The second example method can further include engaging, to the collar of the bracing frame portion, a radial extension of the pull wire that is positioned in a proximal direction in relation to the collar, thereby inhibiting proximal movement of the bracing frame portion in relation to the stentriever portion.
The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.
When used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 90%” may refer to the range of values from 71% to 99%.
For the sake of brevity, the term “clot” is used herein; however, it is to be understood that the systems and methods presented herein can be used to remove other types of obstructions from blood vessels.
When used herein, the terms “tubular” and “tube” are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structure or system is generally illustrated as a substantially right cylindrical structure. However, the tubular system may have a tapered or curved outer surface without departing from the scope of the present invention.
When used herein, the terms “pull wire” and “push tube” are to be construed broadly to include thin elongated structure that can each respectively be pulled and/or pushed to manipulate components of a related device and/or system. The terms “pull wire” and “push tube” can describe a structure having a solid core or a hollow core.
The example systems and methods of treatment described herein generally involve delivering a bracing frame device and an aspiration catheter, which are separate components, to a blood vessel obstruction (e.g. clot). A tubular framework of the bracing frame device can be expanded within a blood vessel between the obstruction and the aspiration catheter. The obstruction can be aspirated, by the aspiration catheter, through a passageway of the tubular framework. The tubular framework can support the blood vessel as negative pressure is created by the aspiration. The bracing frame device can thereby reduce likelihood of blood vessel collapse compared to a similar procedure which does not include the bracing frame device.
In some examples, the aspiration catheter can have a malleable distal portion, and the tubular framework can be expanded within the aspiration catheter to expand the malleable distal portion, thereby expanding a mouth opening of the aspiration catheter. Compared to a catheter having a self-expandable distal portion, the separate aspiration catheter and tubular framework may be made more simply and may be easier to deliver through vasculature. The tubular framework may or may not include a membrane or polymer jacket. Potential advantages of omitting the membrane may include improved deliverability, manufacturability, and cost effectiveness compared to a tubular framework having a membrane or polymer jacket. Regardless of whether the tubular framework includes a membrane or polymer jacket, or not, the separately deliverable catheter and tubular framework can provide improved deliverability, manufacturability, and cost effectiveness compared to a catheter having a built-in expandable frame at its distal end.
In some examples, the system can further include a stentriever that can expand through the obstruction and be retracted to draw the obstruction into the passageway of the tubular framework. The stentriever and tubular framework can be separate components or integral to a combination vascular device.
Various example systems and methods are presented herein. Features from each example are combinable with other examples as understood by persons skilled in the pertinent art.
A distal portion of the aspiration catheter 108, including the mouth 110, can be malleable. The malleable distal portion can be configured to expand in circumference due to a radially outward force applied from a proximal portion of the tubular framework 104 in the deployed configuration. As illustrated, a portion the bracing frame device 102 is expanded within the malleable distal portion of the aspiration catheter 108, thereby expanding the opening of the mouth 110. Because the malleable distal portion of the aspiration catheter 108 is supported by the expanded bracing frame device 102, the malleable distal portion need not have sufficient hoop strength to inhibit collapse of the distal portion. The malleability of the distal portion of the aspiration catheter 108 can result in the aspiration catheter 108 being easier to deliver compared to catheters having distal portions with high hoop strength, particularly expandable distal portions with high hoop strength.
Further, the mouth 110 can be expanded to contact walls of the blood vessel to create a seal between a perimeter of the mouth 110 and the blood vessel walls during aspiration. The tubular framework 104 need not include a membrane or cover to create a seal between the aspiration catheter 108 and the walls of the blood vessel 10.
Although not illustrated as such in
During the steps illustrated in
During delivery and positioning of the bracing frame portion 132, the push tube 138 can be pushed in the distal direction 22 to move the bracing frame portion 132 distally. The push tube 138 can engage to the distal extension 146 so that pushing the push tube 138 also moves the stentriever portion 140 distally. Once the stentriever portion 140 is deployed, the push tube 138 can be pulled in the proximal direction to move the bracing frame portion 132 a desired distance from the stentriever portion 140.
During delivery and positioning of the combination vascular device 130, the pull wire 144 of the stentriever portion 140 can be pushed in the distal direction 24, causing the proximal extension 148 to engage the collar 136 of the bracing frame portion 132, thereby moving the stentriever portion 140 and bracing frame portion 132 distally. The combination vascular device 130 is in a collapsed state, the pull wire 144 can be pushed distally until the bracing frame portion 132 is positioned as desired, then the pull wire 144 can be retracted in the proximal direction to move the stentriever toward the bracing frame portion 132 as desired.
Following the step illustrated in
The system 200 illustrated in
As an alternative to executing steps illustrated in
The tubular frameworks 102, 134, 204 and stentriever structures 120, 140 presented herein are preferably laser cut from a biocompatible metal tube such as nitinol or other suitable material as understood by a person skilled in the pertinent art.
The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of structures and methods, including alternative materials, alternative configurations of component parts, and alternative method steps. Modifications and variations apparent to those having skilled in the pertinent art according to the teachings of this disclosure are intended to be within the scope of the claims which follow.
