DESCRIPTION

The present invention relates to a thrombectomy device that allows extraction of vascular thrombi and to a system for extraction of vascular thrombi from a blood vessel. Background of the invention

Endovascular treatment has been employed in cases of stroke since the 1990s. The number of patients it has been used on has grown slowly but steadily. The main obstacle for wide use of these highly complex treatments is the need for a more coordinated medical system, at various levels. The main goal of these medical networks is to ensure that patients can get to centers with required capabilities within 6-8 hours of symptom onset.

Recently, the first positive randomized study was published (Berkhemer O.A. et al. "A randomized trial of intraarterial treatment for acute ischemic stroke." N Engl J

Med. January 2015; 372: 1 1 -20. doi: 10.1056/NEJMoa141 1587. Epub 17 December 2014. PubMed PMID: 25517348) demonstrating the efficacy of the thrombectomy treatment as compared to more conventional medical treatments by reducing the disability rate three months after a stroke. In addition, four other major similar clinical trials were published in 2015 definitively confirming the superiority of thrombectomy treatment with latest-generation devices by reducing impairment as compared to other medical treatments.

With regard to endovascular treatment, initially the strategy was local perfusion of a fibrinolytic agent through a microcatheter directly into the thrombus. In the early

2000s, a new device was introduced that appeared to be more effective than intraarterial fibrinolysis. It was a spiral that opened around the thrombus, facilitating its extraction (MERCi®). In 2006, a system basically based on bringing a large-gauge catheter in close proximity to the thrombus in order to aspirate it became popular. The catheter is connected to a continuous aspiration pump (Penumbra®).This system has evolved over the years, seeking to attain a catheter with an increasingly large diameter, able to navigate close to the thrombus.

The use of the so-called stent retrievers began around 2009. Their use consists of crossing the thrombus with a microcatheter, then advancing the stent through the microcatheter. Once the distal end of the sheathed device has reached the most distal part of the thrombus, the stent is unsheathed, self-expanding at the thrombus level and captures the thrombus. It is advisable to wait several minutes with the stent expanded to increase the engagement of the thrombus and then withdraw the expanded stent with the intention of it dragging the thrombus. This final step can be done while aspirating through the catheter to try to reverse the flow and thus increase the chances of recovering the thrombus. Stent retrievers have entirely displaced the first-generation devices described above due to their high efficacy, ease to use and reduced procedure times.

In addition, when using a stent retriever, a guide balloon catheter is often used. This catheter only advances to the extracranial carotid (distant from thrombi located in the intracranial arteries). Upon inflation of the balloon situated at the end of the catheter, the catheter is able to stop the flow in the arterial segment distal to the balloon, which is where the thrombus to be extracted is located. By aspirating through it, the flow in the arterial segment distal to the balloon can be reversed in order to facilitate the removal of the thrombus together with the stent retriever.

In summary, there are currently two trends in the use of thrombectomy devices: on one hand the so-called stent retrievers (with or without balloon catheter), and on the other hand devices based on an aspiration catheter (with manual aspiration with syringe or automatic aspiration with aspiration pump). The two techniques can be combined.

An example of a thrombectomy device is described in WO201 1082319, with a variety of interchangeable tips according to the needs of the surgeon during thrombectomy procedure. In all cases, the device described in this document has to cross the interior of the thrombus or pass between the thrombus and the arterial wall before being expanded. Furthermore, in all cases the thrombus must be fragmented to be dissolved by natural or artificial means. As result of these operational principles, this device does not allow the removal of the thrombus in a way that ensures there will be no distal embolization due to a release of clot fragments.

Furthermore, unlike the device of the present invention, it does not have a covered distal end, and, therefore, it is unable to stop the flow of the artery, much less reverse it.

Additionally, stent-retrievers of the present art will, upon deployment, need time (up to three minutes) to acclimatize to the thrombus prior to retrieving the thrombus to minimize fracturing of the thrombus. When dealing with a potential stroke, time is of the essence, and the current device can be used to retrieve the thrombus immediately upon arrival by aspiration.

Therefore, the device according to the present invention is intended to replace aspiration devices, improving on their effectiveness, since it will allow aspiration from a very close proximity to the thrombus and with a large mouth, allowing occlusion of the artery, stopping the flow, and aspirating the entire thrombus without fragmenting it.

The present invention may be used by itself to cut off blood flow, aspirate the thrombus, and remove the thrombus; which means that a physician does not need additional devices to complete these tasks.

An automated embodiment of the present invention also may be used in both traditional (hospital) and non-traditional (nursing home, assisted care facility) environments which may allow for greater deployment and usage of the present invention and hasten the removal of the thrombus, thus significantly improving patient outcomes, as blood flow may be restored in critical areas of the brain within much shorter times. Summary of the invention

The device and system of the present invention manages to resolve the aforesaid disadvantages, providing other advantages that will be described below.

El thrombectomy device according to the invention comprises a delivery catheter, a dilator catheter and a funnel, defining a distal end and a proximal end, said funnel being positionable in a retracted position and in an extended position, and it is characterized in that said funnel also comprises a covering, the diameter of the distal end of the funnel being greater in the extended position than in the retracted position.

Preferably, said covering is a non-permaeable film, e.g. made from expanded polytetrafluoroethylene (ePTFE), and said covering can also comprise polymer fibers oriented parallel to the direction of the length of the dilator catheter.

Furthermore, said funnel is preferably positioned inside the dilator catheter in the retracted position and is positioned at least partially outside the dilator catheter in the extended position.

Said funnel is preferably made from shape-memory materials, such as e.g. nitinol.

If necessary, said funnel can comprise at least one radiopaque marker at its distal end.

According to a preferred embodiment, said covering comprises a lubricious hydrophilic or hydrophobic coating.

Furthermore, said funnel preferably shortens as the diameter of the funnel expands, and the delivery catheter, the dilator catheter, and the funnel are oriented along the same axis.

The device according to the present invention can also comprise a resheathing element, such as e.g. a cannula, for reintroducing the funnel into the delivery catheter.

Said funnel is expanded to blood vessel diameter in order to enable occlusion of the proximal flow and, even, flow reversal upon aspiration through the device, thus facilitating the extraction of the thrombus with a very short dragging distance and with the ability to capture the entire thrombus inside it without fragmentation

The present invention also refers to a system for extraction of vascular thrombi from a blood vessel comprising a thrombectomy device as described previously; a communications channel, a control module, a data storage device, and a guidance system.

Said system can also comprise an imaging device, a first radiomarker, and a second radiomarker, wherein said first radiomarker indicating the location of the distal end of the funnel, and said second radiomarker indicating the location of the vascular thrombus, and a computer assisted controller.

Brief description of the drawings

For a better understanding of the foregoing, several drawings are attached, which schematically and solely by way of non-limiting example represent a practical case of the embodiment.

Figure 1 is a schematic elevational view of the thrombectomy device according to the present invention in its approaching configuration, which is used for clearing the way through blood vessels and reaching the artery where the thrombus is located.

Figure 2 is a schematic elevational view of the thrombectomy device according to the present invention in its retracted or navigational configuration, used to navigate the delivery catheter (carrying inside it the aspiration funnel catheter) to the face of the thrombus.

Figure 3 is a schematic elevational view of the thrombectomy device according to the present invention in its aligned or ready-to-expand configuration, ready to deliver the aspiration funnel.

Figure 4 is a schematic elevational view of the thrombectomy device according to the present invention in its expanded or ready-to-aspirate configuration, when the funnel adapts itself to the vessel shape and faces the thrombus before it is aspirated.

Figure 5 is a schematic elevational view of the thrombectomy device according to the present invention depicting the entire device in its deploying configuration, including all the device components and depicting points with hydrophilic coating.

Figure 6 is a schematic elevational view of the thrombectomy device according to the present invention depicting the entire device in its expanded configuration, including all the device components and depicting points with hydrophilic coating.

Figures 7A, 7B, and 7C present schematic elevational views of a thrombectomy device with a retractor according to the present invention depicting the device in which the device is in several different positions.

Figure 8 is a diagram depicting an automated thrombectomy system according to the present invention.

Description of a preferred embodiment

The thrombectomy device according to the present invention is particularly suited to remove a thrombus from an intracranial artery without causing or allowing the thrombus to fragment and without causing damage to the intracranial artery thus avoiding development of additional thrombi. Though the device is particularly suited for removal of intracranial artery thrombi, it may be used to remove a thrombus in any artery or vein.

The thrombectomy device according to the present invention comprises a tapered dilator catheter 5, an aspiration funnel catheter 2 (composing a covered stent 3 and a pusher element, and in a preferred embodiment a hypotube shaft) and a delivery catheter 1 , each with the definition of a distal end and a proximal end. This device has four different configurations: 1 ) an approaching configuration with the tapered dilator catheter 5 well ahead from other elements of the device and navigating through blood vessels and reaching the thrombus 7 to be removed as depicted in Fig. 1 ; 2) a retracted or navigational configuration with aspiration funnel 2 retracted

(no expansion) inside the delivery catheter 1 and proximally fixed at some distance from the distal end of the delivery catheter 1 , in such configuration the device displays an enhanced navigability and pushability for reaching the thrombus 7 as depicted in Fig. 2; 3) an aligned or ready-to-expand configuration with the distal end of the covered funnel 3 and distal end of delivery catheter 1 aligned and in contact with the thrombus 7 as depicted in Fig. 3; and 4) an expanded or ready-to-aspirate configuration with the covered funnel 3 expanded to the vessel 6 diameter and in close contact with the thrombus 7, delivery catheter 1 proximally fixed at some distance from the distal end of the funnel 3 and the tapered dilator catheter 5 removed, in such configuration the diameter of the funnel 3 distal end is greater than in the previous configurations and it is ready to allocate thrombus 7 when aspired as depicted in Fig. 4.

Advantageously, said funnel 3 is positioned inside the delivery catheter 1 in the retracted or navigational configuration and in the aligned or ready-to-expand configuration and is positioned at least partially outside the delivery catheter 1 in the expanded or ready-to-aspirate configuration.

In accordance with a preferred embodiment, the funnel 3 is a stent covered with a non- permeable film. This stent has a variable diameter, able to expand to the diameter of the blood vessel 6 at a point proximal to the thrombus 7, thus being able to stop the flow and capture the entire thrombus 7 inside it, without needing to fragment it. The stent is preferably self-expandable but may also be expanded by other mechanisms such as an inflated balloon in its interior.

The funnel 3 skeleton is preferably made of shape-memory materials: metals (including metallic alloys), polymers, ceramics or whatever combination of them with suitable mechanical properties. In accordance with a preferred embodiment, said skeleton is a stent made of Nitinol™ (a 50 percent nickel/50 percent titanium alloy, NiTi). This skeleton can include radiopaque markers 13 at its distal end and other strategic points which allow the physician to know the precise location of the device while using fluoroscopy. The funnel 3 may have a covering, said funnel covering 4 is a non-permeable film made of one or combination of more than one biocompatible materials. In accordance with a preferred embodiment, said funnel covering 4 is a biocompatible polymer, elastomeric or other suitable plastic material. In one preferred embodiment, the said polymer is a durable biocompatible polyurethane with elastomeric behavior, which allows funnel 3 resheathing when required. In another preferred embodiment, said funnel covering 4 is expanded polytetrafluoroethylene (ePTFE) with the polymer fibers oriented parallel to the direction of the length of the catheter 1 , and thus with reduced or almost no resistance to expansion and reduced or almost no funnel recoiling without application of an external force.

The expandable covered distal end of the device according to this invention allows artery blood flow to be stopped and even reversed when combined with vacuum. It is thereby possible to aspirate the entire thrombus 7, and minimize and even prevent the detachment of fragments during the procedure or during withdrawal of the device.

Depending upon the specifics of an individual thrombectomy, the funnel 3 of the device described on the present invention can be resheathed within the delivery catheter 1 before, during and after the removal of the thrombus 7. That is, the device allows for the resheathing of the funnel 3 at any time during the procedure, even while the thrombus 7 is being extracted.

Another relevant feature of the device of the present invention is that it is not intended to cross or compress the thrombus 7. Thus, it has the advantage of ensuring the removal of the entirety of the thrombus 7, thus avoiding a possible distal embolization.

Furthermore, said funnel 3 is intended and able to adapt its shape and its length to the surrounding blood vessel 6 so, in the case of encountering a narrow passage during the device removal while carrying the thrombus 7, changes in funnel 3 shape encompass any dimensional change on the thrombus 7, avoiding any leak of thrombus material. While passing through the narrow passage, as the funnel 3 narrows proportionally it also lengthens allowing for the entire thrombus 7 to remain securely within the funnel 3.

Figure 5 shows the thrombectomy device according to the present invention, which comprises a tapered dilator catheter 5, an aspiration funnel 3 and a delivery catheter 1 .

To facilitate the description, the ends of the device are defined as the distal end and the proximal end, with the distal end being the farthest from the user manipulating the device according to the present invention and, therefore, the closest to the thrombus 7 to be removed, and the proximal end being the end closest to the user and, therefore, the farthest from the thrombus 7.

The thrombectomy device according to the present invention can be in four different configurations: approaching configuration (shown in Figure 1 ), retracted or navigational configuration (shown in Figure 2), aligned or ready-to-expand configuration (shown in Figure 3) and expanded or ready-to-aspirate configuration (shown in Figure 4), as will be explained below, with the diameter of the distal end of the funnel 3 greater in the expanded configuration than in any other.

In the retracted and aligned configurations, said funnel 3 is positioned inside the delivery catheter 1 , while in the expanded configuration it is positioned at least partially outside of the delivery catheter 1.

In accordance with a preferred embodiment, said funnel 3 is a stent with a non permeable film covering. The stent funnel 3 is preferably self-expandable but may also be expanded by other mechanisms such as an inflated balloon in its interior.

The funnel 3 is preferably made of any material with shape-memory properties, including metals (even metallic alloys), polymers, ceramics or combination thereof with suitable mechanical properties, and said funnel 3 can have radiopaque markers 13 at its distal end and other strategic points. In accordance with a preferred embodiment, the funnel 3 is made of Nitinol™. Thus, the distal end of the funnel 3 expands upon unsheathing, as it has shape memory and it is self-expandable, and when the funnel 3 exits the delivery catheter 1 at body temperature its natural tendency will be to expand. It should be noted, however, that this expansion can be effected by other systems, e.g., by inflating a balloon of the required diameter in its interior. Furthermore, the said funnel covering 4 is a non-permeable film made of one or combination of more than one biocompatible materials. In accordance with a preferred embodiment, said covering 4 is a biocompatible polymer, elastomeric or other suitable plastic material. In one preferred embodiment, said polymer is a durable biocompatible polyurethane with elastomeric behavior, which allows funnel 3 resheathing when required. In another preferred embodiment, said covering 4 is expanded polytetrafluoroethylene (ePTFE) with the ePTFE polymer fibers oriented parallel to the direction of the length of the catheter 1 , and thus with reduced or almost no resistance to expansion and reduced or almost no funnel 3 recoiling without application of an external force.

In a preferred embodiment of the present invention, said covering 4 can have a lubricious coating 8 (hydrophilic or hydrophobic) and so may other strategic points of every device component, for example catheter tips 9, 10 (shown in Figure 5). Referring again to Figure 4, in one preferred embodiment of the invention the distal funnel 3 is self-expanding. In other embodiments of the present invention, the expansion of the funnel 3 may be accomplished through various mechanical means including usage of a balloon. Advantageously, the expansion of the funnel 3 will enable occlusion of the proximal flow, reversal by aspiration of the flow at the distal arterial segment, a very short thrombus dragging distance and the ability to capture the entire thrombus 7 inside it without fragmentation, facilitating the extraction thereof.

As depicted in Figures 3 and 4, another feature of the self-expandable stented funnel 3 is that the funnel 3 shortens as the funnel 3 expands to the diameter of the blood vessel 6. This decrease in funnel 3 length is inversely proportional to the arterial diameter, that is: the funnel 3 length is shorter in a 5 millimeter diameter artery than in a 2 millimeter diameter artery. Even more advantageously, the self- expandable stented funnel 3 spreads the radial force loaded over the arterial wall over its entire length, thanks to the precise combination of the self-expandable funnel 3 and the biocompatible no permeable film between its struts. In that way, it can be assured that the total pressure exerted on the arterial wall remains constant in all arteries with a diameters between about 2 mm and 15 mm (both inclusive), preferably between about 2 mm and 6 mm.

The device of the present invention bears a superior aspiration power and enables the retrieval of thrombus of multiples sizes, shapes and dimensions thanks to its versatile aspiration funnel. In fact, any of the foreseen configurations of the said funnel is intended to adjust to the vessel walls and its geometry, and to adopt the to the vessel diameter (up to 5.9 mm, 0.232"): this particular feature of the device makes possible to aspirate bigger thrombus and with higher vacuum power than other marketed devices (e. g. Navien 0.064", Penumbra 0.072"). In a preferred embodiment of the present invention, the aspiration funnel catheter 2 is composed of a stent covered with a film and a hypotube (with appropriate connectors at the proximal end) which allows the manipulation of the funnel 3 while aspirating the thrombus 7 and during the device removal procedure, reducing the time required to perform the whole thrombectomy intervention. The thrombectomy device is preferably medium gauge, e.g. 6F (2 millimeter (mm)), without limitation of other sizes according to different needs of device dimensions related to different blood vessel 6 types and diameters. As should be clear the device may have different presentations to fulfill these different needs upon changing the maximum diameter that the self-expandable funnel 3 can reach. In any case, once moved outside the delivery catheter 1 , the distal end of the funnel 3 will expand to the diameter of the artery 6 at that point.

As depicted in Fig. 5, it is preferable to have the tapered dilator catheter 5, the aspiration funnel catheter 2, and the delivery catheter 1 oriented along the same axis. This distribution minimizes transaxial forces over the funnel 3 and the combination of aspiration funnel catheter 2 and the delivery catheter 1. What is more, this distribution enables simultaneous manipulation of all device components. The positioning and operation of the device is assisted by fluoroscopy, and, therefore, the device includes some radiopaque markers.

Referring to Fig. 6, to aspirate the thrombus 7, vacuum is applied through aspiration funnel catheter 2 and the delivery catheter 3: one or both of them. The said aspiration is exerted with an aspiration device which may be a syringe or aspiration pump at the proximal end of the catheters. On applying vacuum, the blood flow is reversed and the thrombus 7 is aspirated into the device.

In order to avoid any leak of the material of the thrombus 7, additionally to the vacuum applied along the device, the inner side of the aspiration funnel 2 can have any physical, chemical, biochemical, mechanical element or combination of them able to retain the thrombus 7 in any circumstances during the procedure. In one preferred embodiment, the said holding system can be made of sharp physical elements such as spikes, skewers, saws, clamps or any combination of them.

At this point, all that remains is to withdraw the device together with the thrombus 7, maintaining the vacuum in the device. This is possible because the arterial system increases its diameter as we go down (e.g., from the cerebral arteries to the aorta), but in the case that a narrow passage is encountered, the funnel 3 is designed to encompass any dimensional change on the thrombus 7, avoiding any leak of thrombus material. While passing through the narrow passage, as the funnel 3 narrows proportionally it also lengthens allowing for the entire thrombus 7 to remain securely within the funnel 3. In the event that the aspiration funnel catheter 2 is removed from delivery catheter 1 by its proximal end, an optional resheathing element may allow the user to reintroduce the funnel 3 into the delivery catheter 1 before further use. Such resheathing element can be any special fixture appended to delivery catheter 1 or a stand alone element which can be rigid or plastic. In one preferred embodiment this element is a modification of the hemostatic valve of the delivery catheter 1 with an appropriate conic closure for closing the aspiration funnel 2 to the diameter of the hemostatic valve. In another preferred embodiment, the resheathing element is a cannula 1 1 or funnel with appropriate conical closure and diameter which can be rigid or plastic; if such element has plastic behavior, it can be adjusted to the hemostatic valve diameter and even inserted on its mouth for facilitate the resheathing.

FIG. 8 depicts a thrombectomy device of the present invention which allows for the automated maneuvering of the thrombectomy device through a vascular system.

The system comprises a radiographic marker 12 indicating the location of the thrombus 7 in an artery 6 and a radiographic marker 13 indicating the location of the thrombectomy device in the vascular system, an imaging device 20 which detects the radiographic markers, a communications channel 22 to provide means to transport the image to a control module 24, the control module 24 programmed to allow for guidance of the deployment of the thrombectomy device and storage of data on a data storage device 26, a means to communicate between the control module and the thrombectomy device, and an automated proximal device 30 which provides a guidance system to deploy the thrombectomy device. The control module may be a programmable logic controller, a computer, or the like. In one preferred embodiment the control module 24 is guided by a computer assisted controller 28. The communications channel 22 can be Ethernet, WIFI, Bluetooth, or the like. The control module 24 is programmed to guide the physician or technician operating the thrombectomy device which allows for the thrombectomy device to be used in non-hospital settings such as nursing homes or assisted care living facilities.

By allowing the thrombectomy device to be used "in the field" the time required to perform the thrombectomy is greatly reduced significantly improving patient outcomes. The control may also be via a controller such as those in use in other current medical devices. In another preferred embodiment, the system may be controlled manually.

As should be readily apparent to those skilled in the art, the device of the present invention is a set of different catheters designed to be used combined as an unique device in one preferred sequence of actions. However its components or specific subsets of them could be used in different sequences than the one preferred and, even, separately or in combination with other devices.

For example, the tapered dilator catheter could be used for clearing the way through blood vessels to any lesion prior to using other devices than the one described on the present invention. Likewise, the subset of delivery catheter and aspiration funnel catheter can be used in combination with the kind of thrombectomy devices known as stent retrievers for securing the fixation of the thrombus and avoiding any leak of its material.

Device Manufacture The individual components of the present invention may be assembled using techniques well known by those skilled in the art. Materials used for the device of the present invention are those of common use for those skilled in the art. Coatings and coverings of specific parts of the device are also those of common use and applied with well know techniques for those skilled in the art.

Method of use

A method for using a thrombectomy device to extract vascular thrombi comprising the steps of introducing the thrombectomy device into a blood vessel, guiding the thrombectomy device to a proximal distance from a thrombus via a dilator catheter, positioning a guide catheter adjacent to the thrombus, deploying a funnel, aspirating the thrombus, encompassing the thrombus into the funnel while keeping thrombus materially intact, and removal of thrombectomy device and thrombus from blood vessel.

While only certain features and embodiments of the invention have been shown and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the claimed invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.