Mechanical thrombectomy device and catheter

Abstract

A thrombectomy device (10) for blood clot removal has a first, proximal, end 5 and a second, distal, end. The thrombectomy device (10) has a main body portion (12) and a catheter (14) extending distally from the main body portion (12). The catheter (14) has an outer sheath (18) surrounding an inner wire (16). The inner wire (16) has a screw thread (20) on its outer surface. The inner wire (16) is rotatable about its longitudinal axis and can be moved relative to the outer sheath (18) and the main body portion (12) reciprocally between a first position proximal to the first end of the thrombectomy device (10) and a second position distal from the first end of the thrombectomy device (10). There is also described a catheter (14) for connection to a main body portion of a thrombectomy device (10).

Description

[0001] MECHANICAL THROMBECTOMY DEVICE AND CATHETER

[0002] The present invention relates to a thrombectomy device for blood clot removal and to a catheter for connection to a main body portion of a thrombectomy device.

[0003] Thrombectomy is a critical medical procedure designed to remove blood clots from blood vessels, thereby restoring normal blood flow. This procedure is particularly vital in acute settings where immediate and urgent care is required for patients experiencing severe and sudden health conditions. Thrombectomy helps prevent significant damage to tissues and organs caused by interrupted blood supply.

[0004] Key blood vessels targeted in thrombectomy include both arteries and veins. Cerebral arteries, such as the middle cerebral artery (MCA), are especially important since clots in these vessels often cause ischemic strokes. Peripheral arteries in the legs and arms can develop clots leading to peripheral artery disease (PAD), while clots in the coronary arteries can result in heart attacks. Deep veins, particularly those in the legs, are prone to deep vein thrombosis (DVT). Clots that form in these veins can travel to the lungs, causing a potentially life-threatening condition known as a pulmonary embolism (PE).

[0005] The thrombectomy procedure typically involves inserting a catheter into the affected vessel through a small incision. The catheter is then navigated through the vascular system to the clot. Various types of thrombectomy devices exist, including aspiration catheters, stent retrievers, and mechanical devices like nets or rotating screws, which can break down, capture, and remove the clot. The goal is to clear a vessel, restore normal blood flow, and prevent further tissue damage.

[0006] Thrombectomy is essential for the acute management of ischemic strokes and patient outcomes are significantly improved when thrombectomy is performed promptly. Thrombectomy also helps prevent severe complications such as pulmonary embolism, severe limb ischemia, and heart attacks by efficiently removing obstructing clots. By directly intervening in the affected blood vessels, thrombectomy plays a crucial role in managing and treating vascular occlusions, thereby preventing severe complications and improving patient prognosis. However, one significant issue with many existing thrombectomy devices is their inability to completely remove the clot, leading to partial recanalisation and the need for additional procedures. During the clot removal process, fragments of the clot can break off and travel downstream, causing new blockages in smaller vessels. This is known as distal embolisation and can lead to further complications and diminish the overall effectiveness of the procedure. Additionally, mechanical thrombectomy devices can sometimes cause trauma to a vessel wall, resulting in dissection, perforation, or other forms of vascular injury, which can lead to bleeding, further clot formation, or long-term vessel damage.

[0007] Navigating a device through complex and tortuous vascular anatomy can be challenging, increasing the risk of complications and reducing the efficiency of clot removal. This issue is particularly problematic in smaller or more distal vessels. Prolonged procedure times can also increase the risk of adverse events and reduce the likelihood of a successful outcome. Some thrombectomy devices require multiple passes to achieve complete clot removal, extending the duration of the procedure and thus increasing risk to the patient.

[0008] Non-mechanical thrombectomy devices tend to use thrombolytic agents to dissolve clots. Advantages of mechanical thrombectomy devices over non-mechanical devices include quick restoration of blood flow, which is crucial in acute settings such as ischemic stroke, where rapid intervention significantly improves patient outcomes. Thrombolytic drugs also increase the risk of bleeding and other complications, making mechanical devices safer for patients at high risk of haemorrhagic events. Additionally, mechanical devices allow for more precise targeting and removal of clots which is particularly beneficial in complex or delicate vascular regions, such as the cerebral arteries, coronary arteries, or small peripheral vessels.

[0009] Known mechanical thrombectomy devices can be complex and expensive, limiting their availability and use, especially in resource-limited settings. The use of these devices also requires significant training and expertise. Furthermore, complex mechanical devices are more likely to malfunction or fail during a procedure, complicating the treatment and necessitating additional interventions. Thus, any improvement in device simplicity, robustness, and ease of manufacture, while maintaining effectiveness, is significantly advantageous.

[0010] It is clear that mechanical thrombectomy devices offer significant advantages in terms of rapid clot removal and reduced reliance on pharmacological agents. They also face several design and operational challenges.

[0011] Examples described herein address at least the above problems faced in the known art by providing an improved mechanical thrombectomy device and catheter.

[0012] According to a first aspect disclosed herein, there is provided a thrombectomy device for blood clot removal, the thrombectomy device having a first, proximal, end and a second, distal, end, the thrombectomy device comprising: a main body portion and a catheter extending distally from the main body portion, wherein the catheter comprises an outer sheath surrounding an inner wire, the inner wire defining a longitudinal axis and comprising a screw thread on the outer surface of the inner wire, wherein the screw thread extends along the longitudinal axis from the distal tip of the inner wire towards the main body portion of the thrombectomy device, wherein the thrombectomy device is configured to rotate the inner wire about its longitudinal axis and relative to the main body portion, and wherein the thrombectomy device is configured to move the inner wire relative to the outer sheath and the main body portion along the longitudinal axis reciprocally between a first position proximal to the first end of the thrombectomy device and a second position distal from the first end of the thrombectomy device.

[0013] In an example, the thrombectomy device comprises a motor configured to rotate the inner wire.

[0014] In an example, the thrombectomy device comprises a motor configured to cause the reciprocal movement of the inner wire. In an example, the thrombectomy device is configured to rotate the outer sheath about the longitudinal axis of the inner wire.

[0015] In an example, the thrombectomy device comprises a motor configured to rotate the outer sheath.

[0016] In an example, the outer sheath is configured to be rotatable concurrently with rotation of the inner sheath.

[0017] In an example, the inner wire is configured to be rotatable at a different rotational speed from the outer sheath.

[0018] In an example, the distal end of the inner wire is surrounded by the outer sheath in the first position of the inner wire and the distal end of the inner wire extends beyond the distal end of the outer sheath in the second position of the inner wire.

[0019] In an example, the screw thread is positioned along the inner wire and terminates at a position spaced apart from the main body portion.

[0020] In an example, the inner wire and outer sheath are flexible.

[0021] In an example, the outer sheath is a separate component which is detachably connectable to the main body portion.

[0022] According to a second aspect disclosed herein, there is provided a catheter for connection to a main body portion of a thrombectomy device for blood clot removal, the catheter comprising: an inner wire; and an outer sheath surrounding the inner wire; the inner wire defining a longitudinal axis and comprising a screw thread on the outer surface of the inner wire, wherein the screw thread extends along the longitudinal axis from a distal tip of the inner wire; wherein the inner wire is rotatable about the longitudinal axis relative to the outer sheath; and wherein the inner wire is movable relative to the outer sheath along the longitudinal axis reciprocally between a first position and a second position.

[0023] The device tends to enable efficient clot removal through combined rotational and reciprocating motion of the inner wire and screw thread. This tends to enhance clot capture and fragmentation while minimising the risk of vessel damage. The screw thread engages with clots, enabling easy transport of debris through the catheter. The configuration of an inner wire within an outer sheath also tends to provide stability and reduces the risk of the catheter clogging. This ensures smooth operation which enhances the effectiveness and safety of the procedure.

[0024] The outer sheath may be configured to rotate about the longitudinal axis of the inner wire. This tends to improve stability and clot disruption. Rotating the outer sheath tends to provide additional control and support to the catheter which reduces the risk of the inner wire contacting a vessel wall and minimises potential trauma. Rotating the outer sheath also tends to help to shear and dislodge clot material more effectively, allowing for smoother and more efficient transport of clot fragments through the catheter. This tends to result in safer and more complete clot removal.

[0025] In some examples, the outer sheath may be configured to rotate concurrently with the inner wire. This tends to result in improved coordination and synergy between the two components which leads to more efficient clot disruption and removal. Concurrent rotation helps to ensure that the inner wire remains centred within the outer sheath. This tends to reduce friction between the outer sheath and the inner wire and minimises the risk of damage to a vessel wall.

[0026] The inner wire may be configured to rotate at a different speed from the outer sheath. Such an arrangement tends to increase the versatility and precision of clot removal. For example, by configuring the inner wire and outer sheath to rotate independently at speeds, the device can optimise the interaction between the screw thread of the inner wire and the clot, enabling more effective fragmentation and capture of clot material. The outer sheath rotation speed can be optimised for shearing clot at a vessel wall, and the inner wire rotation speed can be optimised for dislodging and breaking down clots most efficiently, whilst also minimising the risk of clot fragments slipping through or adhering to the sheath.

[0027] In an example, the catheter is curved along its longitudinal axis, at least towards the distal end of the catheter. A curved catheter tends to improve navigation and access to complex or tortuous vascular anatomies. The curved catheter can more easily reach clots in hard-to-access locations, such as around bends or branches of blood vessels, without exerting excessive force on a vessel wall. Such a design enhances manoeuvrability and control, reduces the risk of vessel trauma, and ensures better alignment with the target area, making it more effective in removing clots in challenging anatomical regions. When rotated, the curved shape of the catheter also sweeps a wider path compared to a straight catheter. This effectively increases the area the catheter can interact with inside a vessel. This broader sweep enables the sheath to engage with a larger surface area of the clot or vessel wall without needing to physically expand its structure, improving its ability to capture and remove clot material more efficiently.

[0028] The inner wire may be configured to reciprocate and rotate concurrently. Such combined motion tends to allow the inner wire to better engage with a clot, breaking it down more thoroughly while simultaneously pushing the fragmented material proximally through the catheter. This dual movement reduces the chances of clot fragments adhering to the vessel wall and thus minimises the risk of the catheter clogging.

[0029] In a first position, the distal end of the inner wire may be surrounded by the outer sheath. This tends to increase the safety of the device by ensuring protection of the surrounding vessel walls. The outer sheath encapsulates and stabilises the inner wire which reduces the risk of the inner wire directly contacting the vessel wall. The outer sheath also helps secure captured clot fragments, preventing them from dislodging or embolising during withdrawal, thereby enhancing the overall control and safety of the procedure.

[0030] Advantageously, in a second position, the distal end of the inner wire extends beyond the distal end of the outer sheath, that is, outwardly of the outer sheath. This enables the exposed inner wire to directly interact with the clot which leads to better penetration, fragmentation, and initial disruption. Such an arrangement also provides a leading edge for the screw thread to pull the clot material into the sheath when retracted, reducing the risk of clot migration and enhancing the efficiency of clot removal.

[0031] In an example, the screw thread is positioned along the inner wire and terminates at a position spaced apart from the main body portion. By confining the screw thread to the distal end of the inner wire, the clot engagement and conveyance capabilities of the catheter are focussed closer to the distal end which is the region in which interaction with the clot occurs. Resistance and friction are reduced along the proximal portion of the wire, which therefore enhances manoeuvrability and makes it easier to control the catheter during a procedure. Unnecessary accumulation of clot material near the main body portion also tends to be prevented. This, again, reduces the risk of clogging and ensures smoother and more efficient clot removal.

[0032] Advantageously, the inner wire and outer sheath are flexible. This improves manoeuvrability and navigation through tortuous or curved vessels.

[0033] The rotation and reciprocation of the inner wire may be activated by a first control. The reciprocation of the outer wire may be activated by a second control. Independent control tends to allow an operator to fine-tune the movement of each component, enabling customised manipulation based on the specific clot characteristics and vessel anatomy.

[0034] A collection bag may be in fluid communication with the catheter and configured to collect blood clots, debris, and any other extracted material for disposal. Incorporating a collection bag in fluid communication with the catheter provides a safe and effective method for capturing and storing blood clots, debris, and other material extracted during a procedure. This tends to prevent extracted material from re-entering the bloodstream, thereby reducing the risk of distal embolisation or other complications. It also tends to simplify the disposal and inspection of the removed material, enhancing procedural safety, minimising contamination, and helping to improve the monitoring of the clot removal process. The collection bag may be positioned external to the main body portion and removable therefrom. This enables quick and safe removal without disrupting the catheter setup, thus making it easier to dispose and replace the bag as needed. It also tends to enable easier inspection and monitoring of the collected material.

[0035] The outer sheath may be removable from the main body portion. The ability to detach the outer sheath from the main body portion means the sheath can be easily replaced or cleaned. It also means different sizes or designs of sheath can be swapped in depending on the procedural requirements. Such adaptability reduces the need for a complete device change which, in turn, improves procedural efficiency and lowers costs.

[0036] The outer sheath may be fastened to a rotating portion of the thrombectomy device via a bayonet mount. Such a mount provides quick, secure attachment and detachment, allowing for easy sheath replacement or repositioning while maintaining stability during rotation and minimising procedure time.

[0037] In an example, a first motor is configured to cause reciprocal movement of the inner wire, a second motor is configured to rotate the inner wire, and a third motor is configured to rotate the outer sheath. The first, second and third motors may all be independent operable. This arrangement tends to facilitate precise and independent control of each component's movements.

[0038] With regard to the screw thread of the inner wire, this may extend from the tip of the inner wire a length in the range of for example 10mm to 100mm. In a particular example, the screw thread extends proximally from the tip of the inner wire a length of 50mm.

[0039] The diameter of the distal tip of the screw thread may be in the range of for example 1mm to 5mm. In a particular example, the diameter of the distal tip of the screw thread is approximately 2.4mm.

[0040] With regard to the pitch of the screw thread, this may be in the range of for example 1mm to 20mm. In a particular example, the pitch of the screw thread is 5mm. Advantageously, the frequency of reciprocation of the inner wire is in the range of for example 0.5Hz to 100Hz. In a particular example, the frequency of reciprocation of the inner wire is 2Hz.

[0041] The rotational speed of the inner wire may be in the range of for example lOOOrpm (revolutions per minute) to 100,000rpm. In a particular example, the rotational speed of the inner wire is 20,000rpm.

[0042] The device may be available with a number of different catheter diameters, for example 2F, 3F, 6F, 9F, 12F (where F is the so-called “French” unit, where one French unit equals 0.33 mm), and the length of the device in examples may be between 50cm and 100cm. The screw thread may be either clockwise or anticlockwise and the crosssection of the catheter may be square, rectangular, triangular, circular, trapezoidal, or any combination thereof.

[0043] Advantageously, a method of using the thrombectomy device may comprise rotating the inner wire about its longitudinal axis and relative to the main body portion, and reciprocating the inner wire relative to the outer sheath and main body portion along the longitudinal axis of the inner wire between a first position proximal to the main body portion and a second position distal from the main body portion.

[0044] The method may further comprise the step of rotating the outer sheath relative to the main body portion and about the longitudinal axis of the inner wire. This tends to provide the advantages discussed above. Furthermore, the method may comprise reciprocating the inner wire such that, in the first position, the distal end of the inner wire is surrounded by the outer sheath, and reciprocating the inner wire such that, in the second position, the distal end of the inner wire extends beyond the distal end of the outer sheath. This also tends to provide the advantages as discussed above.

[0045] In an alternative embodiment, the method may comprise rotating the inner wire about its longitudinal axis and relative to the main body portion, and reciprocating the inner wire relative to the main body portion along the longitudinal axis of the inner wire between a first position proximal to the main body portion and a second position distal from the main body portion. To assist understanding of the present disclosure and to show how embodiments may be put into effect, reference is made by way of example to the accompanying drawings in which:

[0046] Figure 1 is an isometric view of an example of a thrombectomy device according to the present disclosure;

[0047] Figure IB is a side view showing the interior of an example of the thrombectomy device illustrating the mechanism for rotation of an outer sheath;

[0048] Figure 1C is an overhead view of the example of Figure IB;

[0049] Figure 2 is an isometric close-up view of the screw thread which is on a portion of the inner wire of the thrombectomy device;

[0050] Figure 3A is a side view of a portion of the end of the catheter of the thrombectomy device, showing the outer sheath and inner wire with the screw thread extending therefrom;

[0051] Figure 3B is a cross-sectional side view of that shown in Figure 3A, revealing the screw thread extending proximally along the inner wire and terminating at a position spaced apart from the proximal end of the inner wire;

[0052] Figure 3C is a side view of a portion of the end of another example of the thrombectomy device;

[0053] Figure 3D is a perspective view of a portion of the end of another example of the thrombectomy device;

[0054] Figure 4A is an isometric cutout view of an example of the thrombectomy device; Figure 4B is an isometric cutout view of the device of Figure 4B, rotated 180 degrees to show the underside of the thrombectomy device, and with main body casing removed;

[0055] Figure 5 is a side-on cross-sectional view of an example of the thrombectomy device;

[0056] Figure 6 is an isometric detail view of the collar and coupler of an example of the present invention showing (A) the collar of the outer sheath spaced apart from the coupler on the main body of the device, (B) the collar of the outer sheath moved into position to connect to the coupler of the main body of the device, and (C) the outer sheath coupled to the main body of the device via the coupler;

[0057] Figure 7 is a side-view of a portion of an example of the inner wire, showing a coiled portion;

[0058] Figure 8A is an isometric detailed view showing an example of the device with a cam in the forward stroke position;

[0059] Figure 8B is an isometric detailed view showing an example of the device with the cam in the backward stroke position;

[0060] Figure 9A shows details of the dimensions of an example of a screw thread of the inner wire; and

[0061] Figure 9B shows details of the dimensions of an alternative example of the screw thread.

[0062] Referring now to Figure 1, an example of a mechanical thrombectomy device 10 according to the present disclosure is shown. The device 10 is configured for use in removing a clot from a vessel, such as a blood vessel, of a patient or other (animal) subject. The device 10 has a main body portion 12, a catheter 14, and a collection bag 21. The main body portion 12 contains various components, such as one or more motors, gears, power source, etc., as will be discussed further below. The main body portion 12 also enables the device 10 to be conveniently held and manipulated by an operator. The catheter 14, in the context of the present example, is a flexible tube which in use is inserted into the subject’s body to allow blood clots to be removed from blood vessels. The catheter 14 is connectable to and disconnectable from the main body portion 12 at a distal end of the main body portion 12. The collection bag 21 is in fluid communication with the proximal end of the catheter 14.

[0063] The catheter 14 comprises two main components: an inner wire 16 and an outer sheath 18. The outer sheath 18 is a hollow tube that is inserted into the blood vessel. The outer sheath 18 may have a circular cross-sectional shape, though other cross- sectional shapes may be used. The inner wire 16 is located within the hollow interior of the outer sheath 18. The catheter 14 provides a stable pathway to the site of a clot. The outer sheath 18 protects vessel walls and guides the inner wire 16 to the target location.

[0064] In use, the inner wire 16 rotates relative to the main body portion 12 within the outer sheath 18 about the longitudinal axis shared by the inner wire 16 and the outer sheath 18. At the same time as rotating, the inner wire 16 also reciprocates back and forth with respect to the main body portion 12 of the thrombectomy device 10. The tip of the inner wire 16 can therefore be cycled from a position proximal, or closest, to the main body portion 12 of the thrombectomy device 10, to a position distal, or furthest, from the main body portion 12 of the thrombectomy device 10, and back again.

[0065] At the tip, or distal end, of the inner wire 16 is a clot-disrupting mechanism in the form of a screw thread 20, detail of which is shown in Figure 2. In this example, the screw thread 20 is a thread of constant radius, that is, a straight thread. In other examples, some or all of the screw thread 20 may be a tapered thread, that is, a thread of decreasing radius. The screw thread 20 may also be referred to as an auger, or drill bit, or borer, or wimble or the like.

[0066] Rotation of the inner wire 16 causes rotation of the screw thread 20, which, upon engagement with a clot, breaks down and captures the clot. As the inner wire 16, and thus the screw thread 20, rotates, the inner wire 16 mechanically engages the clot, fragments it, and transports the debris through the catheter 14 towards the main body portion 12 for collection in the collection bag 21 and, ultimately, removal.

[0067] The catheter 14 is in fluid communication with the collection bag 21 which is provided to capture and store blood clots and debris that are transported through the catheter 14 by the rotating screw thread 20 of the inner wire 16. Once the clot fragments reach the proximal end of the catheter 14, they can be directed into the collection bag 21 for safe containment and disposal. The collection bag 21 tends to prevent any reentry of clots or debris into the bloodstream and allows healthcare professionals to monitor the volume and type of material being removed. The collection bag 21 tends to ensure that the debris is securely collected and contained during and after the procedure, maintaining a sterile and efficient process for clot removal. The collection bag 21 comprises two compartments. The first compartment, proximal to the catheter 14, is a filter compartment 211 suitable for filtering blood and capturing clots. The second compartment, adjacent to the filter compartment 211 and distal from the catheter 14, is a blood collection compartment 212, suitable for collecting the filtered blood. A drain port is in fluid communication with the blood collection compartment 212. The drain port is normally closed by a plug 213 which can be removed from the drain port to allow filtered blood to drain from the collection bag 21. This may be particularly beneficial in thrombectomy procedures as significant volumes of blood may be involved. Such an arrangement may enable a healthcare professional to collect and potentially return filtered blood to the patient, reducing blood loss.

[0068] The drain port or plug 213 provides a convenient way to manage the filtered blood. After the clot is captured, the filtered blood can be drained from the collection bag. The drain port or plug 213 can therefore either aid the disposal of the blood or, as mentioned above, allow it to be reintroduced into the patient. The ability to drain only filtered blood tends to enhance procedural control and tends to ensure that only blood free of clot is returned to circulation. Furthermore, by having separate filter and blood collection compartments 211, 212, the device 10 minimises the risk of clot contamination in the blood collection compartment.

[0069] In addition to rotation, the reciprocating motion of the inner wire 16 moving proximally and distally relative to the main body portion 12 tends to enhance the efficiency of clot removal. In particular, the reciprocating motion enables the screw thread 20 to engage with clot material, ensuring that it reaches and captures more of the clot. The dynamic reciprocating movement can dislodge stubborn or adherent clots that might not be fully broken down by rotation alone, increasing the effectiveness of the initial clot capture.

[0070] Additionally, the combination of rotational and reciprocating motions provides a dual-action mechanism that breaks the clot into smaller fragments more effectively, reducing the size of the debris being transported through the catheter 14. As the screw thread 20 moves forward and backward, it creates a more aggressive disruption pattern, which helps fragment clots more thoroughly. This tends to ensure that smaller clot pieces are produced, which are easier to transport away through the catheter 14 while reducing the risk of occlusion.

[0071] The reciprocating motion also facilitates the transport of clot fragments through the catheter 14 towards the main body portion 12 and subsequently the collection bag 21. By moving the screw thread 20 in both the longitudinally forward and backward directions, the device can continuously propel fragmented clot material through the catheter 14, preventing clogging or blockage within the catheter 14. This continuous movement keeps the pathway clear and allows for more efficient removal of debris.

[0072] The alternating forward and backward motion can help minimise trauma to a vessel wall by preventing continuous contact with the same area. This can reduce the risk of damage to the vessel lining, making the thrombectomy device 10 safer for use in delicate vascular structures while still maintaining effective clot disruption.

[0073] In this example, in addition to the motion of the screw thread 20, the outer sheath 18, which surrounds the inner rotating and reciprocating screw thread 20, also rotates relative to the main body portion 12. In a specific example, the outer sheath 18 rotates in the same direction as the inner wire 16 and screw thread 20, but at a slower rotational speed.

[0074] The rotation of the outer sheath 18 provides additional stabilisation and guidance for the inner screw thread 20, ensuring that the screw thread 20 remains aligned and properly positioned as it moves through a vessel. This helps maintain a steady and controlled removal process, preventing any deviation or misalignment of the screw thread 20 that could lead to ineffective clot capture or damage to a vessel wall.

[0075] Moreover, rotation of the outer sheath 18 creates a shearing effect at the interface between the outer sheath 18 and a vessel wall, which helps disrupt any clot material that may be in close proximity to or partially adhered to a vessel lining. This shearing motion, combined with the relatively slow rotation speed, gently dislodges clot material without applying excessive force, minimising the risk of vessel injury while still ensuring effective clot removal.

[0076] The slower rotational speed of the outer sheath 18 also aids in channelling the clot debris into the internal space of the outer sheath 18. As the screw thread 20 fragments and propels clot material proximally, the rotation of the outer sheath 18 helps direct these fragments toward the main body portion 12 end of the device 10. The synchronised motion prevents clot fragments from getting caught between the screw thread 20 and the sheath 18, thus reducing the risk of clogging or jamming within the catheter system. Movement of the outer sheath 18 also prevents clot fragments from adhering to or building up along the inner walls of the sheath 18, ensuring the pathway is clear for continuous debris removal. The slower, controlled rotation of the outer sheath 18, in tandem with the reciprocating and rotating motion of the inner wire 16, enhances the overall efficiency of clot removal while maintaining a safe and steady operation, thus reducing potential complications during the thrombectomy procedure. Ensuring more complete and even clot removal reduces the risk of distal embolisation, in which fragments of a clot travel downstream and cause blockages in smaller vessels. Rotation of the outer sheath 18 is driven by a third motor 40, described in detail below. The motor 40 is coupled to the outer sheath via gearing 41. This is shown best in Figures IB, 5 and 6.

[0077] Advantageously, there is also no requirement in the present device for the fragments to be aspirated through the catheter to transport them into an external collection system. Negative pressure from aspiration can cause vessel collapse, incomplete clot removal, or distal embolisation if fragments break off and flow downstream. An aspirated catheter can also become clogged with debris, disrupting the procedure and increasing the risk of complications such as haemolysis, where red blood cells rupture, potentially leading to kidney damage. Aspiration can also result in significant volumes of blood being removed along with a clot, and the suction process can create turbulence which reduces visibility and makes it significantly more difficult to assess whether a clot has been fully removed.

[0078] In use of the present device 10, first the catheter sheath 18, separate from the main body portion 12, is inserted into the blood vessel and navigated to the site of the clot. The inner wire 16 which is protruding from the main body portion 12 is then inserted through the sheath 18. Once the inner wire 16 reaches the clot, the outer sheath 18 is securely fastened to the main body portion 12.

[0079] The portion of the main body portion 12 to which the sheath 18 is fastened is a collar 19. Referring to Figure 5, a sealing washer 50 provides a seal between the interior wall of the collar 19 and the coupler 38. The collar 19 is able to rotate relative to the main body portion 12, to thus provide the rotational movement of the outer sheath 18. In this example, the sheath 18 is fastened to the collar 19 of the main body portion 12 using a bayonet fitting (shown in Figure 6). Two diametrically opposed pins 61 extend from the collar 19 and align with the entry to corresponding L-shape slots 62 on the proximal end of the outer sheath 18 (see Figure 6A). The collar 19 and the end of the sheath 18 are pushed together, allowing the pins 61 to enter the slots 62 (see Figure 6B). Once the collar 19 and sheath 18 are engaged, the sheath 18 and / or collar 19 are rotated approximately 90 degrees causing the pins 61 to slide along the slots into the locking position, securing the two components together. To lock in place, the pins 61 move into a notch under a ledge 63 towards the end of the L-shape slots 62, preventing any sliding back (see Figure 6C). The mechanism is quick to use and simple to operate. Other connection mechanisms may be used, such as a screw thread connection.

[0080] Rotation of the collar 19, and thus, in use, rotation of the outer sheath 18, is activated by a rotation control 22. This takes the form of a button positioned on the main body portion 12. The button is a push button type that can be activated by a light press and a firmer press. A light press temporarily activates the button and deactivates when the pressure is released, while a firm press locks the button in the "on" position, allowing it to stay activated after the pressure is removed. This provides versatility by enabling both momentary and continuous operation, giving the operator more precise control. In the event of sustained use, it also reduces hand fatigue because constant pressure is not needed. The button may also provide a tactile click and resistance change to offer clear feedback to the operator, preventing unintentional activation. The rotation control 22 is shown in Figures 1A, IB and 1C.

[0081] Operation of the inner wire 16 and thus the screw thread 20 is also controlled by a similar button, referred to as a reciprocation control 24. This is also a dual function push button that operates as described above. Operation of the reciprocation control 24 causes the inner wire 16 and screw thread 20 to both rotate and reciprocate simultaneously, as described above. The reciprocation control 24 is shown in Figures 1A, IB, 1C, 4A and 4B.

[0082] The screw thread 20 and outer sheath 18 are therefore independently operable. This enables precise control of the movement of each, allowing an operator to fine-tune their actions based on the clot location, size, and consistency. For example, the outer sheath 18 can be rotated at a lower speed to gently shear the clot material from a vessel wall, while the inner wire 16 can be set to a higher speed for more aggressive fragmentation and removal of the clot.

[0083] Independent control also enhances safety by minimising unnecessary motion of one component while the other component is manipulated. Separate controls therefore offer greater flexibility, precision, and safety during clot removal procedures.

[0084] In addition to the above, and although not shown in the figures, the catheter 14 (and thus the inner wire 16 and outer sheath 18) may be curved along the longitudinal axis, at least towards the distal end of the catheter 14. Curvature of the catheter 14 enables it, during rotation, to cover a diameter larger than itself by using its curvature to extend outward in an arc-like motion when rotated. As the sheath 18 rotates around its own axis, the curved shape sweeps a wider path compared to a straight sheath, effectively increasing the area it can interact with inside a vessel. This broader sweep allows the sheath 18 to engage with a larger surface area of a clot or vessel wall without needing to physically expand its structure. Such a design tends to be advantageous because it enables the sheath 18 to conform to the contours of a vessel, providing more consistent contact with clot material. Improved contact enables more effective disruption, guidance, and capture of clot fragments, particularly in wider or irregularly shaped vessels.

[0085] In an example, the inner wire 16 may be made of a metal. A particularly suitable example is nitinol. Nitinol is a flexible nickel -titanium alloy that is highly elastic and has shape memory. This means it can withstand significant deformation and return to its original shape without permanent damage. It is therefore particularly advantageous to use for navigating tortuous and delicate vascular pathways. The elasticity of nitinol allows the screw thread 20 to maintain its structure and function during complex manoeuvres within a vessel. The high flexibility also reduces the risk of kinking or breaking, ensuring reliable performance. In an example, the screw thread 20 is made of a plastics material which is bonded to the inner wire 16. The screw thread 20 may be 3D printed.

[0086] In a first position, the distal end of the inner wire 16 is surrounded by the outer sheath 18. In a second position, as shown most clearly in Figures 3 A and 3B, the distal end of the inner wire 16 extends beyond the distal end of the outer sheath 18. As such, a portion of the screw thread 20 extends such that it protrudes from the outer sheath 18. In the first position, the distal tip or end of the screw thread 20 is substantially flush with the distal tip or end of the outer sheath 18. In the second position, the distal tip or end of the screw thread 20 protrudes from the outer sheath 18 such that the end portion of the screw thread 20 is no longer surrounded by the outer sheath 18 and at least the main part of the remaining portion of the screw thread 20 remains surrounded by the outer sheath 18.

[0087] As discussed above, in an example operation, the screw thread 20 and inner wire 16 move smoothly and continuously back and forth between the first and second positions in a reciprocating motion. In an example, the frequency of reciprocation may be within the range of for example 0.5Hz to 100Hz. In one specific example, the frequency of reciprocation is 2Hz. The rotational speed of the inner wire 16 and thus the screw thread 20 in the present example is within the range of for example 1000 to 100,000 rpm. In the present example the rotational speed is approximately 20,000 rpm. Figures 2, 3A and 3B show most clearly the screw thread 20. Figures 3A and 3B show the screw thread 20 in its second position relative to the outer sheath 18, with the screw thread 20 extending proximally from the tip of the inner wire 16 a length in the range of for example 10mm to 100mm. In the present example, the screw thread 20 extends proximally along the inner wire 16 approximately 50mm from the tip of the inner wire 16. The outer diameter of the distal tip of the screw thread 20 may for example be in the range of 1mm to 5mm. In the present example, the diameter of the tip of the inner wire 16 is approximately 2.4mm. The pitch of the screw thread 20 is in the range of for example 1mm to 20mm and has a handedness of either clockwise or anticlockwise. In the present example the pitch is approximately 5mm. The inner wire

[0088] 16 may be solid or a hollow tube.

[0089] In another example shown schematically in Figure 3C, an additional coiled wire

[0090] 17 may be located on the screw thread 20. The additional coiled wire 17 may have a diameter or thickness in the range of for example 0.5mm- 1mm. The pitch of the additional coiled wire 17 is greater than the pitch of the screw thread 20. The additional coiled wire 17 provides a further screw thread action to break down, capture, and remove a blood clot.

[0091] In another example shown schematically in Figure 3D, one or more apertures or through holes 23 may be provided in the side wall of the outer sheath 18. The or each aperture 23 may have various cross-sectional shapes, including for example circular, oval, square, etc. The or each aperture 23 may have a width or diameter in the range of for example 0.2mm to 3 mm. The or each aperture 23 is located towards the tip of the inner wire 16. The or each aperture 23 allows blood to escape from the outer sheath 18. The or each aperture 23 can also act as an additional suction hole.

[0092] The catheter 14 may be available in multiple diameters depending on application, for example 2F, 3F, 6F, 9F and 12F. The length of the device 10 may be between 50cm and 100cm and may have a cross-section that is square, rectangular, triangular, circular, trapezoidal, or any combination thereof. In the present example the catheter 14 has a circular cross-section. Referring now to Figure 4A and Figure 4B, the main body portion 12 of the device 10 contains the components that enable simultaneous rotation and reciprocation of the inner wire 16 and thus the screw thread 20, and enable the rotation of the outer sheath 18.

[0093] A cam 28 is driven by a first motor 29 against a first bearing 30 and second bearing 32. As can be seen in the figures, the cam 28 has a generally rounded tear drop cross-sectional shape. The cam 28 is eccentrically mounted to rotate about an axis perpendicular to the longitudinal axis of the main body portion 12. The bearings 30, 32 are therefore urged to move proximally and distally (that is, back and forth parallel to the longitudinal axis of the main body portion 12) by the cam 28 as the cam 28 rotates. The bearings 30, 32 are contained within a channel 34 such that they are restricted to only back and forth motion. The cam 28 efficiently converts rotary motion into linear motion. The shape of the cam 28 can be set to generate precise, controlled reciprocating movements, allowing for specific displacement, timing, and speed adjustments. The smooth, continuous surface of the cam 28 also reduces mechanical stress and wear, providing smooth motion which is advantageous in the medical setting. To illustrate the reciprocal movement, Figure 8A shows an example of the device with the cam 28 in the forward stroke position, i.e. towards the distal end of the main body portion 12, and Figure 8B shows an example of the device with the cam 28 in the backward stroke position, i.e. towards the proximal end of main body portion 12.

[0094] Connected to the bearings 30, 32 is a second motor 36 oriented such that it drives rotation about the longitudinal axis of the device 10. This motor 36 is fastened within the main body portion 12 such that it may slide proximally and distally. As such, when the cam 28 urges the bearings 30, 32 in the proximal direction, the second motor 36 slides in the proximal direction; and when the cam 28 urges the bearings 30, 32 in the distal direction, the second motor 36 slides in the distal direction. The inner wire 16 is fastened to the rotating portion of the second motor 36 by a coupler 38. Thus, activation of the second motor 36 causes the inner wire 16 to rotate and activation of the first motor 29 causes reciprocal movement of the second motor 36 and thus reciprocal movement of the inner wire 16. In this example, the third motor 40 is provided at the distal end of the main body portion 12. Operation of the third motor 40 drives rotation of the collar 19 to which the outer sheath 18 is fixed and thus rotation the outer sheath 18. In particular, in this example, the third motor 40 is coupled to the outer sheath via gearing 41. The gearing 41 comprising a first gear 43 to which the drive shaft of the motor 40 is connected, and a second gear 45 which is engaged with the first gear 43. Operation of the motor 40 drives rotation of the first gear 43, which in turn drives rotation of the second gear 45 and therefore the rotational movement of the coupler 38. Rotation of the coupler 38 in turn rotates the collar 19 and thus the outer sheath 18. The second gear 45 and outer sheath 18 share the same axis of rotation.

[0095] In an example where the outer sheath 18 is configured to not rotate about the longitudinal axis of the inner wire, the thrombectomy device does not include a third motor.

[0096] It will be apparent to the skilled person that one of more motors could be configured to rotate the inner wire relative to the main body portion, one or more motors could be configured to reciprocate the inner wire relative to the main body portion and / or outer sheath, and one or more motors could be configured to rotate the outer sheath relative to the main body portion.

[0097] As mentioned above, the catheter 14 is in fluid communication with the collection bag 21 (not shown in Figure 5). The fluid communication is achieved by use of a conduit 53 (shown in Figure 1) which connects to the collar 19, and thus the outer sheath 18, and passes through the main body portion 12 of the device 10 to connect, at the proximal end, to the collection bag 21. The second gear 45 is positioned such that it shares the same longitudinal axis as the conduit 53 where the conduit 53 connects to the collar 19. The second gear 45 is positioned to surround the conduit 53 and rotate therearound.

[0098] As shown in Figure 5, the inner wire 16 passes through the wall of the conduit 53 to connect with the reciprocation and rotation mechanisms described above which rotate the wire 16 and move the wire 16 back and forth (proximally and distally). A silicone seal 58 and bearing 59 are configured with the wire 16 to ensure no fluid leaks at the point where the wire 16 passes through the conduit wall 53, whilst still enabling the rotation and back and forth motion of the wire 16. A sleeve bearing 55 and O-ring 57 are also provided around the conduit 53 to enable movement and prevent leaks.

[0099] In the examples above, the inner wire 16 is a continuous, substantially longitudinal wire that does not include any external features (other than the screw thread 20). Alternatively, in an example shown in Figure 7, the inner wire 16 may have one or more coiled wire portions 65 along its length. In an example, the or each coiled wire portion has a diameter in the range of 0.25mm to 1.2mm, and in a specific example 0.7mm. Providing a portion of coiled wire along the length of the substantially longitudinal, i.e. straight, wire 16 helps to centralise the wire 16 within the outer sheath 18. This tends to improve the performance of the wire 16 by keeping clearance between the wire 16 and outer sheath 18 constant, thus reducing the chance that clot or debris becomes blocked within the outer sheath 18 when passing along the outer sheath 18 to be removed, and reducing the play, i.e. radial movement, of the wire 16 within the outer sheath 18. Furthermore, as shown in Figure 7, the or each coiled portion 65 may spiral radially such that the diameter increases from a minimum up to a maximum when viewed from proximal to distal end of the wire 16, and then decreases in a spiral to return to the minimum diameter.

[0100] Referring to Figure 9A, in a specific example when the device 10 is available in a catheter diameter of 6F (2mm), the length 71 is approximately 50mm, the pitch 72 is 5mm, the major diameter 73, i.e. the diameter measured at the outermost points, is 1.4mm, and the minor diameter 74, i.e. the diameter measured at the root of the thread, is 0.8mm.

[0101] With regard to Figure 9B, in a specific example when the device 10 is available in a catheter diameter of 9F (3mm), the length 71 is approximately 50mm, the pitch 72 is 5mm, the major diameter 73, i.e. the diameter measured at the outermost points, is 2.4mm, and the minor diameter 74, i.e. the diameter measured at the root of the thread, is 0.8mm.

[0102] Further aspects of the invention are provided by the subject matter of the following clauses: Clause 1. A thrombectomy device for blood clot removal comprising: a handle at a proximal end and a catheter extending distally from the handle, wherein the catheter comprises an outer sheath surrounding an inner wire, the inner wire defining a longitudinal axis and comprising an auger screw thread about said longitudinal axis on the outer surface of the inner wire, the auger screw thread extending from the distal tip of the inner wire proximally towards the handle, wherein the inner wire is configured to rotate about its longitudinal axis and relative to the handle, and wherein the inner wire is configured to reciprocate relative to the outer sheath and handle along said longitudinal axis between a first position proximal to the handle and a second position distal from the handle.

[0103] Clause 2. A thrombectomy device according to Clause 1, wherein the outer sheath is configured to rotate relative to the handle and about the longitudinal axis of the inner wire.

[0104] Clause 3. A thrombectomy device according to Clause 2, further comprising a motor configured to rotate the outer sheath.

[0105] Clause 4. A thrombectomy device according to Clause 2 or Clause 3, wherein the outer sheath is configured to rotate concurrently with the inner sheath.

[0106] Clause 5. A thrombectomy device according to any of Clauses 2 to 4, wherein the inner wire is configured to rotate at a different speed to the outer sheath.

[0107] Clause 6. A thrombectomy device according to any of the preceding Clauses, wherein the catheter is curved.

[0108] Clause 7. A thrombectomy device according to any of the preceding Clauses, wherein the inner wire is configured to reciprocate and rotate concurrently. Clause 8. A thrombectomy device according to any of the preceding Clauses, wherein in the first position, the distal end of the inner wire is surrounded by the outer sheath.

[0109] Clause 9. A thrombectomy device according to any of the preceding Clauses, wherein in the second position, the distal end of the inner wire extends beyond the distal end of the outer sheath.

[0110] Clause 10. A thrombectomy device according to any of the preceding Clauses, wherein the auger screw thread is positioned along the inner wire and terminates at a position spaced apart from the handle.

[0111] Clause 11. A thrombectomy device according to any of the preceding Clauses, wherein the inner wire and outer sheath are flexible.

[0112] Clause 12. A thrombectomy device according to any of the preceding Clauses, wherein the rotation and reciprocation of the inner wire is activated by a reciprocation control.

[0113] Clause 13. A thrombectomy device according to Clause claim 2 in combination with any of Clauses 1 to 12, wherein the rotation of the outer sheath is activated by a rotation control.

[0114] Clause 14. A thrombectomy device according to any of the preceding Clauses, further comprising a collection bag in fluid communication with the catheter and configured to collect blood clots, debris, and any other extracted material for disposal.

[0115] Clause 15. A thrombectomy device according to any of the preceding Clauses, wherein the collection bag is positioned external to the handle and removable therefrom.

[0116] Clause 16. A thrombectomy device according to any of the preceding Clauses, wherein the outer sheath is removable from the handle. Clause 17. A thrombectomy device according to any of the preceding Clauses, wherein the outer sheath fastens to a rotating portion of the thrombectomy device via a bayonet mount.

[0117] Clause 18. A thrombectomy device according to any of the preceding Clauses, further comprising one or more motors configured to rotate and reciprocate the inner wire.

[0118] Clause 19. A thrombectomy device according to any of the preceding Clauses, wherein the auger screw thread extends proximally from the tip of the inner wire a length in the range of 10mm to 100mm, for example the auger screw thread extends proximally from the tip of the inner wire a length of 50mm.

[0119] Clause 20. A thrombectomy device according to any of the preceding Clauses, wherein the diameter of the distal tip of the auger screw thread is in the range of 1mm to 5mm, for example the diameter of the distal tip of the auger screw thread is approximately 2.4mm.

[0120] Clause 21. A thrombectomy device according to any of the preceding Clauses, wherein the pitch of the auger screw thread is in the range of 1mm to 20mm, for example the pitch of the auger screw thread is 5mm and / or wherein the inner wire comprises at least one coiled portion wherein the coil has a diameter in the range of 0.25mm to 1.2mm, for example the diameter of the at least one coil is 0.7mm, and / or wherein the coiled portion comprises a spiral with an increasing and decreasing radial diameter.

[0121] Clause 22. A thrombectomy device for blood clot removal comprising: a handle at a proximal end and a catheter extending distally from the handle, wherein the catheter comprises a wire, the wire defining a longitudinal axis and comprising an auger screw thread about said longitudinal axis on the outer surface of the wire, the auger screw thread extending from the distal tip of the wire proximally towards the handle, wherein the wire is configured to rotate about its longitudinal axis and relative to the handle, and wherein the wire is configured to reciprocate relative to the handle along said longitudinal axis between a first position proximal to the handle and a second position distal from the handle.

[0122] Clause 23. A method of using a thrombectomy device according to any of Clauses 1 to 21, the method comprising the steps of passing the inner wire through the outer sheath, fastening the outer sheath to the distal end of the handle, rotating the inner wire about its longitudinal axis and relative to the handle, and reciprocating the inner wire relative to the outer sheath and handle along the longitudinal axis of the inner wire between a first position proximal to the handle and a second position distal from the handle.

[0123] Clause 24. A method of using a thrombectomy device according to Clause 23, further comprising the step of rotating the outer sheath relative to the handle and about the longitudinal axis of the inner wire.

[0124] Clause 25. A method of using a thrombectomy device according to Clause 23 or Clause 24, further comprising the steps of reciprocating the inner wire such that, in the first position, the distal end of the inner wire is surrounded by the outer sheath, and reciprocating the inner wire such that, in the second position, the distal end of the inner wire extends beyond the distal end of the outer sheath.

[0125] The examples described herein are to be understood as illustrative examples of embodiments of the invention. Further embodiments and examples are envisaged. Any feature described in relation to any one example or embodiment may be used alone or in combination with other features. In addition, any feature described in relation to any one example or embodiment may also be used in combination with one or more features of any other of the examples or embodiments, or any combination of any other of the examples or embodiments. Furthermore, equivalents and modifications not described herein may also be employed within the scope of the invention, which is defined in the claims.

Claims

1. CLAIMS1. A thrombectomy device for blood clot removal, the thrombectomy device having a first, proximal, end and a second, distal, end, the thrombectomy device comprising: a main body portion and a catheter extending distally from the main body portion, wherein the catheter comprises an outer sheath surrounding an inner wire, the inner wire defining a longitudinal axis and comprising a screw thread on the outer surface of the inner wire, wherein the screw thread extends along the longitudinal axis from the distal tip of the inner wire towards the main body portion of the thrombectomy device, wherein the thrombectomy device is configured to rotate the inner wire about its longitudinal axis and relative to the main body portion, and wherein the thrombectomy device is configured to move the inner wire relative to the outer sheath and the main body portion along the longitudinal axis reciprocally between a first position proximal to the first end of the thrombectomy device and a second position distal from the first end of the thrombectomy device.

2. A thrombectomy device according claim 1, comprising a motor configured to rotate the inner wire.

3. A thrombectomy device according claim 1 or claim 2, comprising a motor configured to cause the reciprocal movement of the inner wire.

4. A thrombectomy device according to any of claims 1 to 3, wherein the thrombectomy device is configured to rotate the outer sheath about the longitudinal axis of the inner wire.

5. A thrombectomy device according to claim 4, comprising a motor configured to rotate the outer sheath.

6. A thrombectomy device according to claim 4 or claim 5, wherein the outer sheath is configured to be rotatable concurrently with rotation of the inner sheath.

7. A thrombectomy device according to any of claims 4 to 6, wherein the inner wire is configured to be rotatable at a different rotational speed from the outer sheath.

8. A thrombectomy device according to any of claims 1 to 7, wherein the distal end of the inner wire is surrounded by the outer sheath in the first position of the inner wire and the distal end of the inner wire extends beyond the distal end of the outer sheath in the second position of the inner wire.

9. A thrombectomy device according to any of claims 1 to 8, wherein the screw thread is positioned along the inner wire and terminates at a position spaced apart from the main body portion.

10. A thrombectomy device according to any of claims 1 to 9, wherein the inner wire and outer sheath are flexible.

11. A thrombectomy device according to any of claims 1 to 10, wherein the outer sheath is a separate component which is detachably connectable to the main body portion.

12. A thrombectomy device according any of claims 1 to 11, comprising an additional screw thread on the screw thread of the outer surface of the inner wire, the pitch of the additional screw thread being greater than the pitch of the screw thread of the outer surface of the inner wire.

13. A thrombectomy device according any of claims 1 to 11, wherein a side wall of the outer sheath comprises at least one through hole.

14. A catheter for connection to a main body portion of a thrombectomy device for blood clot removal, the catheter comprising: an inner wire; and an outer sheath surrounding the inner wire;the inner wire defining a longitudinal axis and comprising a screw thread on the outer surface of the inner wire, wherein the screw thread extends along the longitudinal axis from a distal tip of the inner wire; wherein the inner wire is rotatable about the longitudinal axis relative to the outer sheath; and wherein the inner wire is movable relative to the outer sheath along the longitudinal axis reciprocally between a first position and a second position.

15. A catheter according to claim 14, wherein the inner wire and outer sheath are flexible.

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