Optical transmission microcatheter device and method thereof

Abstract

Optical transmission microcatheter devices and methods of endovascular embolization are described herein. A microcatheter device is provided that includes a working lumen and a mechanical protection waveguide. The working lumen has at least one outlet port at a distal end of the working lumen and is configured to provide an intravascular injection of a photoactivated embolic agent (PEA) to a target vessel via the at least one outlet port. The mechanical protection waveguide (MPW) is operatively connected to the working lumen and configured to emit at least one electromagnetic wave via the at least one outlet port for delivery to the target blood vessel.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 386,279, filed December 6, 2022, the contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to the design of intravascular microcatheters. In some aspects, this disclosure relates to methods for therapeutic embolization via the injection of photoactivated embolic agents or therapeutic agents. Background Technology

[0003] Endovascular embolization is a minimally invasive catheter-based interventional procedure designed to stop localized blood flow in the peripheral vascular system to address conditions including hypervascular tumors, arteriovenous malformations, subdural hematomas, and aneurysms. Diseased vessels, often difficult to reach via open surgery, can be accessed through punctures of superficial vessels, but can be treated with catheters containing a selected flow-controlled device or agent. Endovascular embolization can significantly reduce perioperative risks and patient recovery time when used as a primary or adjunct method for disease management.

[0004] Currently available embolization devices and agents in clinical practice include mechanical devices (such as detachable coils), shunts, precipitated liquid polymers, and suspended particulate materials. Metal coils used for aneurysm treatment are prone to recanalization due to insufficient filling of the aneurysm cavity caused by device compression. Shunts (which have recently become a popular choice for aneurysm treatment) are prone to poor adhesion to the wall of the parent artery, leading to residual aneurysm perfusion. Shunts also require patients to undergo dual antiplatelet therapy for life. Existing injectable embolization agents (such as Onyx (Medtronic)...) TM Uncontrolled coagulation observed in the study has led to off-target embolism, resulting in ischemic attacks and catheter entrapment, which may dissect healthy blood vessels and cause rupture.

[0005] Commercially available neurovascular microcatheters for endovascular embolization (such as the SL10 (Stryker) and Sceptor XC (Balt)) have extremely low profiles (typically less than 1 mm in outer diameter) and high compliance, requiring only about 1 gram of force to bend the distal end. This allows for the deployment of emboli in highly complex locations within neurovascular networks. Trade-offs between size, navigation, flexibility, and infusion pressure are often important in microcatheter design. Microcatheters typically lack the additional features available only at larger sizes, such as drawstrings for active steering. The limited capabilities of microcatheters beyond infusion and balloon occlusion hinder innovation in novel emboli. For example, the application of balloon-assisted deployment of Onyx HD-500 precipitated liquid embolic agents in cerebral aneurysms may be limited due to a lack of deployment control, and there are several case reports of off-target embolization in the literature.

[0006] Clinically, there is a need for devices and methods that can achieve endovascular embolization, possessing: i) precise spatiotemporal control of embolization deployment; ii) high shape conformability to various vascular morphologies; and iii) excellent mechanical properties of the embolus, without structural compaction or rupture, to minimize reperfusion of the treated vessel or other iatrogenic events. Summary of the Invention

[0007] According to some embodiments, a microcatheter device is provided, comprising a working lumen and a mechanically protected waveguide (MPW). The working lumen has at least one outlet port at its distal end and is configured to deliver an intravascular injection of a photoactivated embolic agent (PEA) to a target vessel via the at least one outlet port. The mechanically protected waveguide (MPW) is operatively connected to the working lumen and is configured to emit at least one electromagnetic wave via the at least one outlet port for delivery to the target vessel.

[0008] According to some embodiments, the mechanically protected waveguide is: at least partially embedded in the wall of the working cavity; co-extruded into the wall of the working cavity; at least partially separated from the working cavity by at least one barrier; coupled to an external segment of the working cavity; woven into a braided portion of the microcatheter; and / or, at least partially disposed within an enclosed space separated from the working cavity.

[0009] According to some embodiments, the microcatheter device further includes a pre-cured region within the microcatheter and adjacent to the at least one outlet port, the pre-cured region being configured to adjust the viscosity of the PEA prior to its injection into the target blood vessel.

[0010] According to some implementations, the mechanically protected waveguide includes multimode optical fiber.

[0011] According to some implementations, the working cavity includes biocompatible materials such as nylon, Vestamid, Pebax, and PTFE.

[0012] According to some embodiments, the mechanical protection waveguide is configured to transmit the electromagnetic wave to the target blood vessel and / or the pre-cured area.

[0013] According to some embodiments, the microcatheter device further includes at least one beamforming element. According to some embodiments, the at least one beamforming element includes one or more optical components, such as lenses, diffusers, filters, reflectors, and masks. According to some embodiments, the at least one beamforming element is configured to provide at least one radially emitted beam to be delivered to the pre-cured area.

[0014] According to some embodiments, the microcatheter device further includes at least one transmitting beam, the at least one transmitting beam including: a first beam pointing to the target blood vessel and a second beam pointing to the pre-cured area.

[0015] According to some embodiments, the at least one beamforming element includes a plurality of beamforming elements configured to provide a plurality of radial beams in a plurality of directions.

[0016] According to some embodiments, the mechanically protected waveguide includes a fiber Bragg grating (FBG). According to some embodiments, the FBG is tuned to a secondary wavelength and configured to back-reflect light having a second wavelength. According to some embodiments, the FBG element is configured to selectively propagate light of a first wavelength in a first direction and light of a second wavelength in a second direction based on the frequency of the electromagnetic wave. According to some embodiments, the first direction is toward the at least one exit port, and the second direction is a radial direction.

[0017] According to some embodiments, the microcatheter device further includes a detachment mechanism configured to detach the coagulated PEA from the distal end of the microcatheter. According to some embodiments, the detachment of the PEA is induced by emitting an electromagnetic wave of a predetermined wavelength through the MPW, the electromagnetic wave being configured to photodegrade the cross-linked PEA. According to some embodiments, the detachment mechanism includes a superhydrophobic coating applied to the outer surface of the distal end near the at least one outlet port.

[0018] According to some embodiments, at least a portion of the distal end includes a reflective coating and / or reflective material and is configured to reflect excess light emitted radially outward in a radially inward direction.

[0019] According to some embodiments, the microcatheter device further includes an optical cavity operatively connected to the pre-cured region.

[0020] According to some implementations, the mechanically protected waveguide includes an optical fiber configured to guide at least one evanescent wave into physical contact with the PEA.

[0021] According to some embodiments, the optical refractive index can be detected in the PEA. According to some embodiments, the microcatheter further includes a detection mechanism configured to detect changes in the optical refractive index of the medium surrounding the mechanically protected waveguide.

[0022] According to some embodiments, the microcatheter device further includes a power injector configured to supply fluid to the outlet port at a predetermined pressure and determine changes in the back pressure of the fluid. According to some embodiments, the determination of changes in the back pressure of the fluid is performed in real time.

[0023] According to some embodiments, the microcatheter device further includes a detachable tip. According to some embodiments, the detachable tip is configured to dissolve within the target blood vessel over a predetermined time period (typically tens to hundreds of seconds). According to some embodiments, the detachable tip is biocompatible.

[0024] According to some implementations, the distal end of the mechanically protected waveguide floats freely within the pre-cured area.

[0025] According to some embodiments, the microcatheter device further includes at least one valve mechanism.

[0026] According to some embodiments, the distal end of the working lumen is tapered. According to some embodiments, the size of the taper is determined to provide a desired flow velocity to the target vessel via a PEA.

[0027] According to some embodiments, the microcatheter device further includes a solid element inserted into the working lumen.

[0028] According to some embodiments, the microcatheter device further includes at least one additional liner in the pre-cured region, the at least one additional liner being configured to restrict adhesion of the cured PEA to the inner and / or outer surfaces of the working cavity.

[0029] According to some embodiments, a method for endovascular embolization is provided, the method comprising: introducing a microcatheter device according to any one of the foregoing embodiments into the target blood vessel; injecting a photoactivated embolic agent (PEA) into the target blood vessel until a desired volume of the target blood vessel is filled; and, after or simultaneously with the injection, emitting an electromagnetic wave at a coagulation wavelength toward the PEA and toward the PEA disposed in the target blood vessel. According to some embodiments, the emission includes emitting the electromagnetic wave toward the pre-cured area.

[0030] According to some embodiments, the method further includes determining whether the microcatheter device has malfunctioned before emitting the electromagnetic wave at the coagulation wavelength. According to some embodiments, determining whether the microcatheter device has malfunctioned includes sensing at least one electromagnetic wave reflected from the PEA.

[0031] According to some embodiments, the method further includes removing the microcatheter from the coagulated PEA and the target vessel after emitting the electromagnetic wave at the coagulation wavelength. According to some embodiments, removing the microcatheter includes detaching the microcatheter from the coagulated PEA. According to some embodiments, detaching the microcatheter includes activating a photodegradation mechanism.

[0032] According to some embodiments, the method further includes determining the coagulation state of the PEA. According to some embodiments, the determination is performed in real time or near real time. According to some embodiments, the determination includes detecting at least one electromagnetic wave back-reflected from the PEA disposed in the target blood vessel. Attached Figure Description

[0033] To better understand the various implementations or embodiments described herein and to more clearly illustrate how these embodiments can be implemented, reference will now be made only by way of example to the accompanying drawings, in which:

[0034] Figures 1a to 1f Some example vascular morphologies for receiving embolization using an optical delivery microcatheter device (100) and a photoactivated embolic agent (109) are depicted.

[0035] Figure 2a An example microcatheter (100) according to a non-limiting embodiment is depicted, having a working lumen (101) for delivering a photoactivated embolic agent (PEA) and located within an example target vessel (200, 203, 204, or 205). A mechanically protected waveguide (MPW) (102) is embedded in the wall of the working lumen (101). Similarly, according to a non-limiting embodiment, the distal end (134) of the microcatheter has an outlet port (113) at which PEA (109) is injected into the target vessel.

[0036] Figure 2b An example embodiment of a microcatheter according to a non-limiting implementation is depicted, wherein the MPW (102) is configured such that a region within the working lumen (101) is exposed to electromagnetic waves (104).

[0037] Figure 2c An example embodiment according to a non-limiting implementation is depicted, wherein the MPW (102) actively transmits electromagnetic waves (104) toward the PEA (109).

[0038] Figures 3a to 3h Several iterations of how mechanical protection is applied to the MPW (102) according to a non-limiting implementation are described.

[0039] Figure 4 A plurality of beamforming elements (105) are depicted according to a non-limiting embodiment, which guide electromagnetic waves (104) toward a pre-cured region (103) and through an outlet port (113).

[0040] Figure 5 A plurality of beamforming elements (105) are depicted according to a non-limiting embodiment, which guide electromagnetic waves radially inward and / or radially outward (106) relative to the working cavity.

[0041] Figure 6a A plurality of beamforming elements (105) are depicted according to a non-limiting embodiment, which guide electromagnetic waves (106 and / or 104) radially inward, radially outward and / or in the same direction at the exit port (113). Figure 6b Examples of how multiple beamforming elements (105) according to a non-limiting embodiment can be arranged together with an MPW (102) are depicted.

[0042] Figure 7 A fiber Bragg grating (FBG) element (108) positioned between transmitting electromagnetic waves (104, 114) according to a non-limiting embodiment is depicted.

[0043] Figure 8a A microcatheter (100) according to a non-limiting embodiment is shown, wherein the cured PEA (111) has been fully cured and / or over-cured into the microcatheter (100) within the target vessel and is not easily removed. Figure 8b-1 The emission beam of a PEA (116) intended to soften / dissolve solidified PEA according to a non-limiting embodiment is depicted. Figure 8b-2 A softened region of the cured PEA (117) according to a non-limiting embodiment is depicted, which allows the microcatheter (100) and the bonded PEA (115) to separate.

[0044] Figure 9 An example microcatheter according to a non-limiting embodiment is depicted, the distal end of which is coated with a coating or lining (118) that restricts adhesion between the microcatheter (100) and the cured PEA (111). The coating may be hydrophobic or hydrophilic.

[0045] Figure 10 An example microcatheter according to a non-limiting embodiment is depicted, wherein the distal end is composed of a reflective material (119).

[0046] Figure 11a An example microcatheter according to a non-limiting embodiment is depicted, which emits electromagnetic waves (104) intended to thicken uncured PEA (109). Figure 11b An example microcatheter is depicted in which the PEA (111) is fully cured and reflected electromagnetic waves from the cured PEA (112) are directed into the MPW (102).

[0047] Figure 12 An example microcatheter according to a non-limiting embodiment is depicted, wherein the MPW (102) is in direct contact with the PEA (109). A cloaking source (120) is propagating. A cloaking wave (122) is created (122) and a reflected cloaking source is formed.

[0048] Figure 13A power injector capable of inferring back pressure (123) according to a non-limiting embodiment is depicted, which is hydraulically connected to a working cavity (101).

[0049] Figure 14 A power injector capable of inferring back pressure (123) according to a non-limiting embodiment is depicted, which is hydraulically connected to a working cavity (101). A malfunction or leakage (124) occurs within the hydraulic system (in this case, the working cavity (101)).

[0050] Figure 15 An example microcatheter according to a non-limiting embodiment is depicted, wherein the MPW (102) fails and / or breaks (130) along its length.

[0051] Figure 16 An example microcatheter according to a non-limiting embodiment is depicted, which has a detachable end (132) mounted at its distal end.

[0052] Figure 17 A detailed example flowchart (400) depicts how a PEA, according to a non-limiting implementation, can be used with a microcatheter.

[0053] Figure 18a An example microcatheter according to a non-limiting embodiment is depicted, wherein an outlet pressure reducing valve (135) is attached to the outlet port of the working lumen. Figure 18b A scenario depicting the curing of PEA into a solid according to a non-limiting embodiment is described. The pressure within the working cavity forces the cured PEA through an outlet pressure reducing valve (also referred to herein as an outlet port valve).

[0054] Figure 19 The working cavity material of a diffuser that acts as an electromagnetic wave, according to a non-limiting embodiment, is described.

[0055] Figure 20a and Figure 20b A widened pre-cured region (137) according to a non-limiting embodiment is depicted to help change the flow rate and increase the area exposed to electromagnetic waves.

[0056] Figure 21a and Figure 21b Non-restricted configurations of pre-cured regions with tapered or narrowed walls are depicted, resulting in smaller cross-sectional areas at the ends.

[0057] Figure 22a and Figure 22b Simplified example flowcharts (300a and 300b) according to non-limiting embodiments are depicted, which outline the use of microcatheter devices to deposit PEA.

[0058] Figure 23 Examples of multiple MPWs (102) housed within respective channels and terminated at various locations for multiple beam directions, according to a non-limiting implementation, are depicted. Detailed Implementation

[0059] It should be understood that, for simplicity and clarity, reference numerals in the accompanying drawings may be repeated where deemed appropriate to indicate corresponding or similar elements or steps. Furthermore, numerous specific details have been set forth to provide a more comprehensive understanding of the embodiments described herein. However, those skilled in the art should understand that the embodiments described herein can be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the embodiments described herein. Moreover, this specification should not be construed as limiting the scope of the embodiments described herein in any way, but rather as describing only implementations of the various embodiments described herein.

[0060] Ideally, the existing limitations of medical devices and materials available for clinical use in endovascular embolization should be addressed through a multifaceted solution that tackles the challenges associated with the embolic material and its applicator (i.e., microcatheter). One solution could be to make the embolic material responsive to stimulation, allowing the coagulation process to be triggered on demand, while the catheter could have the ability to trigger this coagulation process.

[0061] This article describes an optical delivery microcatheter device and a method for intravascular injection of photoactivated embolic agents.

[0062] This application generally provides a means of endovascular embolization to induce controlled cessation of local blood flow in the context of various vascular diseases. One aspect of the systems and methods described herein relates to a microcatheter design capable of delivering a photoactivated embolic agent (PEA) while simultaneously emitting electromagnetic waves through a mechanically protected waveguide (MPW) to reach target vascular anatomy, such as the target vessel and / or the interior of the microcatheter device.

[0063] On the one hand, the properties of PEA allow the material to initially exist in a flowable liquid state, and once exposed to electromagnetic radiation of a predetermined wavelength (typically 200 nm to 600 nm), it solidifies to form a soft, elastic solid. Therefore, one purpose of the ability of optical delivery microcatheter devices to emit electromagnetic radiation is to controllably trigger the coagulation of PEA to form an embolic plug at a desired location within a diseased vascular system.

[0064] According to some implementations, PEA is a yield stress fluid. PEA can exhibit solid-like properties in its static state, while under stress (such as infusion pressure on the catheter lumen), it can enter a flowable state. In some instances, this property of PEA facilitates injection through microcatheters, while simultaneously providing initial resistance to blood flow by restoring the PEA to its solid-like state once blood enters the vascular system. This initial resistance to blood flow enhances the effectiveness of photocoagulation by preventing material washout. Subsequent photocoagulation of PEA is typically irreversible and further stabilizes the injected material within the vascular lumen.

[0065] The microcatheter consists of a working lumen that, according to some embodiments, allows PEA to be delivered to the target vessel using a syringe, which can be manually driven or driven by an infusion pump. Typically, a guidewire is used to navigate the microcatheter to the target vessel. The PEA is then injected through the microcatheter and enters the target vessel through the outlet port of the microcatheter. The PEA deposited in the target vessel can be exposed to electromagnetic waves to induce cross-linking, thereby increasing the viscosity and modulus of the PEA and ultimately transforming it into a soft, elastic solid material. One property of the microcatheter is that the waveguide is mechanically protected (MPW), otherwise the use of accessories such as guidewires and high-pressure hydraulic injection could damage the waveguide and deposit electromagnetic waves in unintended locations.

[0066] According to some implementations, a pre-cured region is included within the distal portion of the microcatheter. This pre-cured region can be exposed to electromagnetic waves before the PEA leaves the microcatheter and enters the target vessel, allowing the PEA to thicken or coagulate. Operators may need to occlude a wide variety of target vessels, including, but not limited to, high-flow areas or areas where excessive penetration of the vascular system must be avoided due to the presence of critical downstream structures. Pre-curing the PEA allows for better localization of embolic deposits, which can be achieved by keeping it tethered to the catheter tip or by size exclusion when the coagulated mass is trapped in the distal vascular system (typically smaller in size). For example, a higher viscosity PEA is often suitable if the target vessel is relatively large and has high flow, while a lower viscosity or shape-fit PEA is generally recommended if the target vessel is relatively narrow and has low flow. This controllability allows operators to exert a degree of control over the PEA.

[0067] Several methods exist for providing mechanical protection for the envisioned waveguide. These methods include, but are not limited to: i) partially embedding the MPW into the working cavity; ii) co-extruding the working cavity wall with the MPW; iii) having a barrier between the working cavity and the MPW; iv) attaching the MPW to the outside of the working cavity; v) weaving the waveguide between the braided layers; vi) protecting it separately from the working cavity; and / or vii) partially embedding the MPW into the wall of the working cavity while allowing the region to physically move into the working cavity. However, it should be understood that any suitable means or combination of means may be contemplated for mechanically protecting the waveguide.

[0068] MPWs can be configured in several different ways to emit electromagnetic waves. For example, electromagnetic waves can be emitted towards the exit port of the microcatheter, through the exit port towards the target vessel, towards the pre-cured area, and / or radially towards the target vessel. This can be achieved by placing the MPW within the working lumen. Additionally, beamforming elements (such as micro-optical components) can be added anywhere suitable along the optical path of the MPW (or on the distal side of the MPW) to further assist in directing the electromagnetic waves towards any target area. For complex beam profiles and orientations, beamforming elements are typically required.

[0069] According to some embodiments, a fiber Bragg grating (FBG) is added along the length of the MPW. This addition typically provides a means of selecting a specific electromagnetic wave for a particular direction. The FBG is tuned such that it reflects electromagnetic waves of a specific bandwidth, while electromagnetic waves of the remaining spectrum are transmitted through. An example use of the FBG is to orient it between two different beamforming elements. If a bandwidth is selected that matches the reflection distribution of the FBG, all beamforming elements close to the FBG will emit electromagnetic waves. If the bandwidth does not match the reflection distribution of the FBG, that bandwidth will be transmitted through. This mechanism typically provides the operator with greater control. A foreseeable application is when the operator wants to independently change the incident power of the electromagnetic waves in the pre-cured area relative to the incident power at the exit port.

[0070] According to some embodiments, multiple wavelengths are used; the dominant wavelength of the electromagnetic wave will crosslink and thicken or coagulate the PEA. Secondary wavelengths can be used to lyse and liquefy certain types of coagulated PEA. This is helpful if a microcatheter is stuck in PEA and cannot be removed while still attached to a blood vessel. Alternatively, a hydrophobic coating can be applied to the distal end of the microcatheter to ensure that the cured PEA and the microcatheter do not bond firmly together.

[0071] According to some embodiments, multiple MPWs are integrated to achieve various electromagnetic energy distributions. For example, in a dual MPW configuration, one MPW may terminate near the pre-cured region, while the other MPW continues to the end of the conduit. With such a configuration, the MPWs can operate sequentially or collaboratively.

[0072] In ideal operation of the pre-cured section of the catheter, a predetermined level of electromagnetic energy (typically in the range of about 1 mJ to about 1000 mJ at suitable wavelengths (typically about 200 nm to 600 nm)) will reliably thicken or solidify the flowable PEA into a soft solid, regardless of variations in infusion force that may be applied by the user during use. In other words, according to some implementations, the system needs to be sufficiently insensitive to such input variations to avoid unintentionally releasing uncured material (in the case of excessively rapid infusion) or clogging the pre-cured area (in the case of excessively slow infusion), either of which could lead to surgical complications.

[0073] Furthermore, the ability of the pre-cured region combined with an electromagnetic energy source to continuously thicken or coagulate injected PEA can be independent of catheter placement or local hemodynamics within a given vascular system. For example, the catheter tip may not necessarily be parallel to the vessel wall, but rather point towards it. This restricted catheter positioning can interfere with the outflow of PEA from the catheter port and affect the coagulation process.

[0074] According to some embodiments, one or more valve mechanisms may be employed within the catheter. The valve may be pressure-activated, thereby restricting the passage of uncured PEA until a predetermined pressure differential (typically from about one-tenth to several hundred PSI) is reached over a given segment of the catheter. On one hand, such a valve mechanism may be employed at the distal port of the catheter to prevent accidental release of uncured PEA (flowable under low pressure) while allowing cured PEA (flowable under high pressure) to be released and deposited into the target vascular system.

[0075] To prevent accidental release of uncured precursors, some embodiments may employ a tapered inner wall at the distal end of the conduit. This tapered wall can generally reduce the flow velocity of the precursor in the pre-cured region, thereby providing greater exposure to electromagnetic energy and ensuring more robust thickening or solidification. In some embodiments, the tapered wall can also be used to reflect the forward-firing beam emitted by the waveguide toward the pre-cured region, thereby further enhancing the efficiency of thickening or solidification.

[0076] To improve crosslinking efficiency within the pre-cured region, a reflective material can be added around it, causing any radially emitted electromagnetic waves to be reflected towards the pre-cured region. This also guides most of the incident electromagnetic waves toward the exit port (and target vessel). The reflective material can be made of a radiopaque material.

[0077] In some implementations, there will be back-reflected electromagnetic waves from the uncured PEA. As the PEA transitions from uncured to cured, the optical properties of the back-reflected electromagnetic waves can change. The total power, spectrum, or polarization characteristics can vary based on the PEA state. Evaluating these EM wave characteristics at the back end can help inform the operator about the PEA's condition.

[0078] Similar to monitoring back-reflected electromagnetic waves from the PEA, in some implementations, the evanescent wave power can be inferred by monitoring reflected signals from the FBG. This would also be an indirect way of informing the operator of the PEA's status. Further details are provided in the detailed description.

[0079] If PEA is included in the hydraulic system of a microcatheter, this can cause an increase in the system's back pressure when the PEA changes from a liquid to a solid state. The viscosity state of the PEA can be inferred using a power injector capable of detecting pressure. Conversely, according to some embodiments, if a break or malfunction exists in the hydraulic system, the back pressure will drop sharply, and this will also be sensed by the power injector.

[0080] Another failure scenario is a break or defect in the MPW. If any defect is induced in the optical path, this will lead to an increase in the returned electromagnetic waves (called return loss). Monitoring for sudden changes is one way to infer whether any damage has occurred to the MPW.

[0081] According to some embodiments, the distal portion may have a detachable tip. Detachment methods may include one or more of the following (in any suitable combination): physical separation by force causing a predetermined tear point to rupture; physical separation by dissolving the predetermined tear point with emitted electromagnetic waves (or secondary electromagnetic waves); or physical separation by dissolving the predetermined tear point using a biocompatible injectable gel specifically designed for dissolution. The detachable tip may be made of a biocompatible material that dissolves when retained as an implantable device. A non-limiting example of such a material is polyvinyl alcohol (PVA), which is known to dissolve slowly in water and has previously been micronized and used as a temporary embolus.

[0082] According to some embodiments, typical uses of the described microcatheter will include navigating the microcatheter to the treatment site using a conventional guidewire. A pre-embolization scan of the disease site will be performed using digital subtraction angiography. At this point, the operator can determine the viscosity type of PEA required for optimal filling of the treatment site based on the disease type. The operator typically selects the appropriate EM wave power for the desired viscosity and injects the PEA accordingly. The operator typically injects the PEA into the lesion until it is filled. Using fluoroscopy, the operator can confirm when the treatment site is filled. Post-injection curing of the PEA will be performed by emitting EM waves to the treatment site until the embolization plug coagulates. Several methods are described herein to monitor PEA coagulation. After coagulation is complete, the operator can remove the microcatheter from the treatment site. According to some embodiments, if removal of the catheter is difficult due to adhesion between the catheter and the coagulated PEA, the operator can activate the disengagement mechanism discussed herein. According to some embodiments, several fault detection methods are monitored throughout the use of the microcatheter. Faults include, but are not limited to, leakage from the catheter or breakage in the MPW.

[0083] Turn attention Figures 1a to 1f These figures depict the use of an optical delivery microcatheter device (100) in combination with a photoactivated embolic agent (PEA) (109, 111) within example vascular morphologies (200, 201, 202) according to a non-limiting embodiment. For example, in a given blood vessel, an operator typically assesses the local vascular morphology (such as nominal blood flow rate, vessel diameter, and downstream anatomy) to determine the optimal injection protocol. Figures 1a to 1f Some non-restrictive examples are provided. Figure 1a and Figure 1b The first example shown is a hypervascular tumor (202) consisting of a terminal vascular system composed of capillaries (204). In this case, PEA (109) is injected into the structure from the larger feeding artery (203) at the end of the optical delivery microcatheter device (100). It should be noted here that the permeation... Figures 1a to 1f The shaded areas represent uncured PEA (109), while the cross-hatched areas represent photoactivated and solidified PEA (111). Due to the inherent rheological properties of PEA (109), which may include shear recovery, it is reasonable to expect that the material released into the microvascular system will form a plug up to the injection point. Figure 1b In the example shown, the operator may choose to initially inject the precursor PEA (109) into the lesion without electromagnetic wave emission (i.e., without thickening or coagulation) to achieve distal penetration. The proximal portion of the injected PEA is then photoactivated (111), which generally stabilizes the entire structure. Figure 1c and Figure 1dThe next example shown is an arteriovenous malformation (201), which is a high-pressure shunt lesion between an artery (205) and a vein (206), consisting of numerous intertwined lesion vessels (201). In this case, because the structure is not terminal and drains into the venous network (206), excessive penetration of the PEA (109) can cause downstream ischemic events. The operator can address this situation in several ways. One approach is to perform temporary balloon occlusion proximal to the injection site, placing the injected PEA (109) under reduced hemostatic pressure (driving the PEA distally), thereby improving the operator's control over infusion pressure and penetration depth. Another approach is to simply pre-select a higher viscosity PEA (109), provided that the PEA can be injected via an optical delivery microcatheter device (100), making the PEA more resistant to excessive flow into the distal vascular system. Alternatively, PEA (109) can be injected simultaneously, and a predetermined electromagnetic radiation can be emitted towards the PEA (109) as it enters the blood vessel, thereby causing the PEA (111) to thicken or coagulate. This method can simultaneously benefit from lower infusion pressures and higher occlusion capabilities. Note that the effective distribution of uncured PEA (109) and photoactivated PEA (111) occupies the lesion (201) can vary considerably depending on the injection technique chosen, and it should be understood that... Figure 1d This illustrates an exemplary scenario. For example, if the operator chooses to inject uncured PEA (109) while continuously emitting electromagnetic energy, the entire structure could include photoactivated PEA (111). Figure 1e and Figure 1f In the final example of the aneurysm shown, the embolization material must be strictly confined within the small aneurysm space (200) without leakage into the parent artery (250), and the operator may wish to use a balloon catheter (251) for embolization. The injection of PEA and the emission of electromagnetic waves into the aneurysm balloon (200) can be performed sequentially or simultaneously to seal the structure. It is understood that the photoactivated (with at least some degree of thickening or coagulation) PEA (111) has completely filled the aneurysm space (200) and coagulated within it. Figures 1a to 1f The target vessels described in the text are considered to be, but are not limited to, 200, 203, 204, and 205.

[0084] Figure 2aAn example is depicted at the distal end of a microcatheter device (100) in its simplest form, contained within a target vessel (200, 203, 204, or 205). The microcatheter device includes a working lumen (101) configured to deliver an intravascular injection of a photoactivated embolic agent (PEA) via at least one outlet port (113). The microcatheter device also includes a mechanically connected waveguide (102) operatively connected to the working lumen (101) and configured to emit at least one electromagnetic wave via at least one outlet port (113) for delivery to the target vessel (delivery of PEA via electromagnetic wave). For simplicity, Figures 2a to 2c The fluid connection of PEA to a syringe or accessory, which is not depicted, is not described. This syringe or accessory is capable of applying pressure to allow PEA to flow through the working lumen (101) and out through the outlet port (113). The outlet port (113) is located distal to the working lumen (101) at (134). Because the PEA is delivered to a target vascular anatomy, such as a target vessel (200, 203, 204, or 205) within the human anatomy, the diameter of the working lumen (101) is typically large enough to accommodate the conventional guidewire used by the surgeon to navigate to the target vessel (200, 203, 204, or 205) and also facilitates the injection of PEA. When navigating to the target vessel, the operator can apply hydraulic pressure to the working lumen (101) to deposit PEA. Exposure to electromagnetic waves is required to crosslink and coagulate the PEA in the target vessel. The electromagnetic waves propagate along a waveguide (102), and the transmission of these electromagnetic waves is controlled by the operator. Delivering PEA and / or navigating through the working cavity with a guidewire can damage the unprotected waveguide. To limit damage to the waveguide (102), mechanical protection is provided to the waveguide (102). All embodiments of the waveguide (102) discussed herein have at least some degree of mechanical protection, and the waveguide will hereafter be referred to as a mechanically protected waveguide (MPW) (102).

[0085] Figure 2b and Figure 2c A variation of an example microcatheter (100) according to a non-limiting embodiment is depicted. The MPW (102) is recessed from the distal end (134) to provide a pre-cured area (103) within the microcatheter device (100) and near the outlet port (113), between the MPW (102) and the outlet port (113). Figure 2b and Figure 2cThe electromagnetic waves (104) are shown radiating within the pre-curing region (103), towards the outlet port (113), and externally towards the outlet port (113), and into the target vessel. The pre-curing region (103) is configured to help regulate the viscosity of the PEA before it is injected into the target vessel (200, 203, 204, or 205). The recessed MPW (102) allows the PEA (109) to thicken within the pre-curing region (103) and before entering the target vessel. Dynamically adjusting the total power of the electromagnetic waves (104) provides the operator with a degree of control by controlling the viscosity of the PEA (109) as it enters the target vessel (200, 203, 204, or 205). It should be understood that different disease sites will require different viscosities. Figure 2b A scenario is depicted where PEA is absent in the working cavity (101). For example... Figure 2c As shown, uncured PEA (109) inside the working cavity is depicted.

[0086] MPW(102) can be (but is not limited to) made of multimode fiber. Other suitable MPW(102) materials may include single-mode fiber, glass rod, contained fluid channels, channels contained in reflective material, or any suitable combination thereof.

[0087] Figures 3a to 3h Several examples of ways and degrees of providing mechanical protection to the MPW(102) are described. Figure 3a An example is shown where no additional mechanical protection is provided to the MPW (102). The entire length of the MPW (102) will be in physical contact with the PEA or guidewire. Therefore, the guidewire will be unprotected during normal use of the working cavity (101). Figure 3b An example manner of providing mechanical protection is depicted, wherein the MPW (102) is extruded (co-extruded) together with the wall (138) of the working cavity (101). In this manner, the MPW (102) is configured to withstand the temperatures required for cavity extrusion. Other methods include, but are not limited to, refluxing the working cavity (101) such that the MPW (102) is placed or otherwise at least partially embedded within the wall (138). Figure 3cA secondary cavity (107) is depicted within the wall (138) of the working cavity (101). The secondary cavity (107) is large enough to accommodate the MPW (102) passing through it. In this respect, the arrangement of the secondary cavity (107) provides an enclosing space, such as an enclosing space (107a), in which the MPW (102) is at least partially separated from the working cavity. Dual-cavity extruders can be manufactured, and the MPW (102) can be supplied through the secondary cavity (107). Due to the dimensional constraints of the overall diameter of the microcatheter, the wall clearance between the MPW (102) and the inner diameter of the secondary cavity (107) is typically minimal. The inner diameter of the secondary cavity (107) or other enclosing spaces separated from the working cavity, as well as the coating on the MPW (102), can be used to help guide the MPW (102) through throughout the entire length of the manufacturing process of the working cavity (101). Reflowing, adding glue, or heat shrinking are examples of methods for securing the MPW (102) within the working cavity (101) so that independent translation does not occur during manufacturing or use. Figure 3d An MPW (102) is depicted adhering to the outer wall of the working cavity (101). Mounting on an outer section of the working cavity (101), such as the outer wall (138), also facilitates mechanical separation between the PEA and / or guidewire (and thus provides at least some mechanical protection). Various methods can be used to adhere it to the wall, including (but not limited to) heat-shrinkable wall attachments, the use of adhesives, or reflow. Figures 3b to 3d In the example implementation shown, the PEA and / or guidewire are typically not in direct contact with the MPW (102), which further reduces the likelihood of failure. Figure 3h Another example embodiment of mechanical protection is shown in which the MPW (102) is woven within the braided portion (139) and / or wound layer of the microcatheter. The presence of braided material (139) and / or wound material within the microcatheter is common and can cause blockage of the MPW (102). However, according to some embodiments, the MPW may also be woven between the individual braided layers (139) or wound layers. Another embodiment of mechanical protection is to embed the MPW (102) within a separate working lumen (101), intended for use in conjunction with the microcatheter discussed herein. Figure 3e and Figure 3f In this process, the MPW (102) adheres to and is protected by the secondary cavity (107). Specifically, for the pre-cured area, Figure 3e and Figure 3fAt least a portion of the MPW (102) depicted herein has the ability to float within the working cavity (101) to allow electromagnetic waves (104) to be deposited in the center of the working cavity (101). If a solid element (such as a guide wire) is inserted into the working cavity (101), the MPW (102) will have the freedom to return to the center of the secondary cavity (107) within the pre-cured area (103).

[0088] Figure 3g Another example mechanism for mechanical protection of the MPW (102) is shown, wherein the MPW has the ability to retract or move into the secondary cavity (107) when the solid element is inserted into the working cavity (101). Once the solid element is reinserted, the MPW (102) can be moved back into the working cavity.

[0090] The working lumen (101) of the microcatheter can be made of a biocompatible material. Examples of suitable biocompatible materials are nylon and Vestam. TM Pebax TM And polytetrafluoroethylene (PTFE). Any suitable biocompatible materials were also considered.

[0091] The MPW (102) can be configured to emit electromagnetic waves (104) in various directions (see, for example, Figure 6). According to some embodiments, the electromagnetic waves (104) can be emitted toward the outlet port (113), through the outlet port (113) toward the target vessel (e.g., target vessels (200, 203, 204, or 205)), toward the pre-cured area (103), and / or radially toward the target vessel. These locations may be referred to herein as (but are not limited to) target areas. According to some embodiments, the MPW (102) can be physically oriented and fixed in place by, for example, adhesive epoxy or reflow technology.

[0092] Additionally, at least one beamforming element (e.g., a micro-optical component) (105) can be added at any suitable location along the optical path length of the MPW (102) to further assist in directing the electromagnetic wave (104) toward any target region. The MPW (102) will emit light based on numerical aperture (NA). Adding a beamforming element (105) can help provide the ability to further direct light toward the target region. For more complex beam profiles and orientations, multiple beamforming elements (105) may be required. Figure 4An example of a beamforming element (105) for extending electromagnetic waves to achieve coverage within the pre-cured region (103) and toward and through the exit port (113) is shown. In this figure, the orientation of the MPW (102) includes a recessed position of the MPW (102), which can provide better coverage of the pre-cured region (103). Alternatively, conceptually, the MPW (102) can be further oriented into the working cavity (101), which also increases the size of the pre-cured region (103). The beamforming element (105) can be mechanically attached to the MPW (102) or physically separated from the MPW (102) as long as the electromagnetic waves (104) are affected by it.

[0093] Figure 5 The example microcatheter depicted also utilizes a beamforming element; however, the electromagnetic waves are directed toward the pre-cured region and / or radially outward. Examples of suitable beamforming elements (105) that guide electromagnetic waves in one or more directions include, but are not limited to, prisms or folded mirrors operatively coupled to focusing or defocusing components. According to some embodiments, at least one beamforming element includes one or more optical components, such as lenses, diffusers, filters, reflectors, prisms, folded mirrors, and masks. Any suitable beamforming element or combination thereof is contemplated.

[0094] Figure 6a A beamforming element (105) is also depicted, wherein electromagnetic waves (104 and 106) are directed toward a pre-cured region (103) for delivery to that pre-cured region, toward an outlet port (113), toward a target vessel, and / or radially directed (providing at least one radially emitted beam for delivery to the pre-cured region). In addition to prisms, folded mirrors, focusing / defocusing elements, and / or beam splitters may be used, wherein a predetermined beam splitting ratio optimally optimizes the crosslinking in the PEA (109).

[0095] According to some embodiments, at least one beamforming element is configured to provide at least a first emission beam directed toward the target blood vessel and a second emission beam toward the pre-cured region. (See, for example) Figure 6a 。 )

[0096] According to some embodiments, at least one beamforming element includes a plurality of beamforming elements configured to provide a plurality of radially emitted beams in a plurality of directions. (See, for example) Figure 6b 。 )

[0097] According to some implementations, the MPW (102) includes a fiber Bragg grating (FBG). Figure 7An FBG (108) is depicted along the length of the MPW (102). The FBG (108) is a device configured to reflect electromagnetic waves of a specific bandwidth while allowing the transmission of the remaining spectrum of the electromagnetic waves. According to some embodiments, the FBG is tuned to a secondary wavelength and configured to back-reflect light having a second wavelength. For example, the FBG (108) may be configured to reflect the spectrum of λ2. When the electromagnetic wave of λ2 propagates through the MPW (102), most of the electromagnetic wave is typically reflected and leaves the MPW (102) as a secondary solidified wavelength (114). According to some embodiments, the FBG element is configured to selectively propagate light of a first wavelength in a first direction and light of a second wavelength in a second direction based on the frequency of the electromagnetic wave. For example, if an electromagnetic wave with a propagating spectrum of λ1 (e.g., an electromagnetic wave in the ultraviolet range) and whose spectral distribution does not overlap with λ2 is propagated, the electromagnetic wave will typically propagate through the FBG (108) and propagate in a direction different from the secondary solidified wavelength (114). When the microcatheter is configured with a back-end laser capable of providing both λ1 and λ2, the FBG (108) can provide a means of non-uniformly distributing the total amount of emitted electromagnetic waves (104, 114) in various directions (104 is a non-limiting example of light guided in a first direction toward the exit port, and 114 is a non-limiting example of light guided in a second direction in the radial direction, and vice versa). Furthermore, if the back-end laser has the ability to select λ1 and / or λ2, the operator has the ability to select which emitted electromagnetic wave (104 or 114) to propagate to the PEA (109). The filtering mechanism presented herein is not limited to the FBG of a spectral filter component. Any suitable spectral component can be envisioned to replace or combine with the FBG.

[0098] According to some embodiments, the microcatheter (100) further includes a disengagement mechanism configured to disengage the coagulated PEA from the distal end of the microcatheter. Figures 8a to 8b-2 A release mechanism is depicted in which a photodissolving wavelength (116) is used to dissolve the solidified PEA (111) to release the stuck microcatheter (100) from the solidified PEA (115). Figure 8a A microcatheter is shown embedded and held within a fully cured PEA (111). A portion of the fully cured PEA (115) inadvertently adheres to the microcatheter (100), and removal of the microcatheter (100) will detach the PEA (111) from the target vessel. According to some embodiments, detachment of the PEA is induced by emitting electromagnetic waves of a predetermined wavelength through the MPW, the electromagnetic waves being configured to photodegrade the crosslinked PEA (e.g., via an operatively connected photodegradation mechanism). Figure 8b-1 The photodissolution wavelength (116) is shown to be different from the spectrum of the electromagnetic waves used to cure PEA (104, 106 and / or 114). Figure 8b-2The results are shown at a photodissolving wavelength (116) capable of breaking down cured PEA (115) back into uncured PEA (117). This allows the embedded microcatheter (100) to be released from the cured PEA (115). The photodissolving wavelength (116) can also be directed in multiple directions as needed.

[0099] According to some embodiments, the detachment mechanism includes a superhydrophobic coating applied to the outer surface of the distal end near at least one outlet port. Figure 9 An example mechanism for reducing the occurrence of microcatheter (100) embedding into cured PEA (111) according to a non-limiting embodiment is depicted. A portion of the distal end (134) of the microcatheter that is intended to be unintentionally embedded in the cured PEA (111) is coated with a hydrophobic coating (118). This portion of the distal end (134) may also include a pre-cured region (103). Those skilled in the art will generally understand that such a hydrophobic coating may include non-limiting examples such as silica-based materials and fluoropolymers. The hydrophobic coating generally reduces the likelihood of contact between the PEA (111) and the microcatheter (100) material. Most microcatheters on the market are typically characterized by a hydrophilic coating along their entire length for easy insertion into the body when wet. However, according to some embodiments, typically only the very distal end of the microcatheter (100) (e.g., the distal end of the working lumen and the outer surface of the distal end of the microcatheter) may be hydrophobic to avoid interfering with the majority of the desired hydrophilic coating of the microcatheter. Additionally, the coating (118) can be a type of material that does not adhere to critical adhesive elements in the uncured and cured PEA (109, 111). The coating can be applied to the material, or the entire area can be constituted by the coating.

[0100] According to some embodiments, at least a portion of the distal end of the working cavity includes a reflective coating and / or reflective material configured to reflect excess light emitted radially outward in a radially inward direction. Figure 10 A non-limiting embodiment is shown in which an optical reflector (119) is applied to a portion of a pre-cured region (103). The optical reflector (119) is an optical cavity in which electromagnetic waves (104, 106, 114, or 116) leaving the pre-cured region (103) are reflected radially inward toward the pre-cured region (103). This helps to ensure higher efficiency within the pre-cured region (103) and directs a greater number of electromagnetic waves (104, 106, 114, 116) toward the exit port (113). An example of the optical reflector (119) is a metallic material, such as a transmissive marking strip. Other suitable modes for providing an optical cavity operatively connected to the pre-cured region include, but are not limited to, coating the inner surface of the cavity with a reflective metallic coating (such as gold, chromium, and platinum) by processes such as vapor deposition.

[0101] Now let's turn our attention to... Figure 11a and Figure 11b .exist Figure 11a In this process, a microcatheter has injected PEA (109) into the target blood vessel. Electromagnetic waves (104) are transmitted to the PEA (109) to induce curing or viscosity change. Reflected electromagnetic waves from the uncured PEA (110) are guided back into the MPW (102). In the rear end (not depicted), an electromagnetic wave sensor can create a baseline reading based on any of power, spectrum, or polarization. Figure 11b The state of fully cured PEA (111) and the reflected electromagnetic waves from cured PEA (112) are shown directed into the MPW (102). Inside the rear end (not depicted), an electromagnetic wave sensor compares the measurements to a baseline reading. This will provide the operator with an indicator of the relative cure-ness. The state of PEA (109 or 111) can also be observed when the dissolution of PEA (111) is detected during removal of the stuck microcatheter. Observed properties include back-reflection power, polarization state, and wavelength.

[0102] According to some embodiments, the MPW includes an optical fiber element configured to guide at least one evanescent wave into physical contact with the PEA. According to some embodiments, the optical refractive index can be detected within the PEA. Figure 12 An example embodiment of an MPW (102) is demonstrated, wherein a portion of the MPW is in physical contact (133) with a PEA (109). The MPW (102) can transmit wavelengths specific to the cryptic function, referred to as cryptic wave sources (121). If a small portion of the MPW (102) is exposed to the PEA (109), the cryptic wave source (121) will leak into the PEA (109) due to the cryptic wave phenomenon. The leaked portion is the cryptic wave (120). The intensity of the cryptic wave is directly related to the optical refractive index of the PEA (109) in physical contact (133). In this embodiment, an FBG (108) or other fiber optic element is also embedded, which is specifically configured to reflect the electromagnetic waves of the cryptic wave source (120). The intensity of the reflected cryptic wave source (122) is directly related to the intensity of the cryptic wave (120). Therefore, if the intensity of the elliptic wave (120) increases, this will lead to a decrease in the reflected elliptic wave source (122), and vice versa. Considering that the elliptic wave (120) is related to the refractive index of PEA (109), the measurement of the relative intensity of the reflected elliptic wave source (122) and the known elliptic wave is an indicator of the refractive index of PEA (109). The possible characteristics of PEA (109) are based on the refractive index variation of its viscosity and / or its cured state.

[0103] According to some embodiments, the microconductor (100) further includes a detection mechanism (140) for measuring changes in optical power, polarization state, and / or wavelength, the detection mechanism being configured to detect changes in the optical refractive index of the medium surrounding the mechanically protected waveguide.

[0104] According to some embodiments, the microcatheter (100) further includes a power injector configured to deliver fluid to an outlet port at a predetermined pressure and to determine changes in the back pressure of the fluid. Figure 13 An example configuration of a microcatheter is demonstrated, in which the microcatheter is hydraulically attached to a power injector (123) capable of detecting the back pressure of PEA (109, 111). The power injector (123) can inject PEA (109) at a given rate and the internal pressure of the system. The power injector (123) will provide the same force on the hydraulic system as the PEA transitions from an uncured state (109) to a cured state (111). If the internal pressure increases beyond a certain relative threshold, it typically indicates some degree of blockage within the microcatheter or solidification at the distal end of the working cavity (101). This is an indirect method for detecting the viscosity of PEA (109, 111). This situation can then be reported to the operator. Figure 14 An alternative example configuration is shown where a break or leak (124) is introduced anywhere within the hydraulic system, including the working cavity (101) . A break would cause a sudden drop in internal pressure, which is typically detected by the power injector (123) and reported to the operator. According to some implementations, the determination of changes in the fluid back pressure is performed in real time or near real time.

[0105] Now let's turn our attention to... Figure 15 This figure illustrates an example of detecting a fault scenario within an MPW (102). Electromagnetic waves (104) propagate within the MPW (102), and a small number of back-reflected electromagnetic waves (131) can be detected along the same line. If any defect or fracture (130) is introduced on the MPW (102), a reflection point is created. The intensity of the back-reflected electromagnetic waves (131) will increase. Monitoring the relative increase in the intensity of the back-reflected electromagnetic waves (131) can indicate a fracture (130) on the MPW (102).

[0106] Figure 16Another example embodiment of the described microcatheter device is shown, wherein the distal end of the microcatheter is detachable from the working lumen. In scenarios where the PEA has been fully cured (111), the distal end (134) of the microcatheter may be encapsulated and not easily removed. The distal portion may have a detachable tip (132). Some methods for enabling the tip to detach from the microcatheter include some of the following (alone or in any suitable combination): physical separation by force causing a predetermined tear point to break; physical separation by dissolving the predetermined tear point with emitted electromagnetic waves; physical separation by dissolving the predetermined tear point using a biocompatible injectable gel specifically designed for dissolution. Furthermore, the detachable tip (132) will remain in the cured PEA (111) and subsequently remain in the target vessel. The detachable tip (132) will be made of or otherwise contain a biocompatible material that will naturally dissolve over time in the presence of blood flow. According to some embodiments, the detachable tip is configured to dissolve within the target vessel over a predetermined time period.

[0107] According to some implementation methods, the distal end of the MPW floats freely within the pre-cured area, as discussed further below.

[0108] According to some embodiments, the microcatheter (100) further includes at least one valve mechanism, as discussed further below.

[0109] In some implementations, the distal end of the working cavity is tapered. This increases local resistance to PEA flow and thus reduces PEA flow rate under constant-pressure drive mechanisms (e.g., when the operator applies a constant force to the syringe plunger). Combined with implementations featuring a pre-cured region, this localized flow reduction can, in a sense, increase the time exposed to EM energy emitted by the MPW, thereby improving thickening / coagulation efficiency and preventing uncured PEA from being accidentally released into the anatomical structure.

[0110] According to some embodiments, the microcatheter (100) further includes a solid element, such as a guidewire, inserted into the working lumen.

[0111] Figure 22a and Figure 22bTwo non-limiting methods 300a and 300b for endovascular embolization using the microcatheter device described herein are depicted. In the first case, the operator typically begins by performing necessary intravascular navigation to reach the target vessel. Once the catheter is correctly placed within the target vessel, the operator should inject PEA without activating the EM power source. Subsequently, once the target vessel is sufficiently filled with uncured PEA, the operator should enable the EM power source to fire through the distal region of the microcatheter device, thereby coagulating the PEA. In the second case, similarly, the operator should perform necessary intravascular navigation to reach the target vessel. Once the optimal positioning of the microcatheter device is confirmed, the operator should synchronously activate the electromagnetic power source during PEA injection, causing the PEA to thicken or coagulate as it exits through the distal region of the microcatheter device. The first method 300a may be referred to as the sequential method, while the second method 300b may be referred to as the synergistic or synchronous method. In cases of relatively low local blood flow and / or where maximum penetration and conformity of the PEA to the treatment site is desired (e.g., in the case of a highly vascularized tumor composed of numerous capillaries), a sequential approach may typically be preferred. A simultaneous approach, where the PEA thickens or coagulates during injection, will reduce the conformity of the PEA to various vessels, but may be preferred when there are critical structures downstream and the PEA must not excessively penetrate the treatment site, in which case there is a risk of local ischemia of the critical structures (e.g., arteriovenous malformations).

[0112] Now let's turn our attention to... Figure 17 , Figure 22a and Figure 22b These figures depict flowcharts of methods (300a), (300b), and (400) for endovascular embolization using the microcatheter device described herein, according to non-limiting embodiments. The following discussion of methods (300a), (300b), and (400) will lead to a further understanding of the device described herein. However, it should be understood that methods (300a), (300b), and / or (400) may be modified and do not need to work in exactly the same combination as discussed herein, and such modifications are within the scope of this embodiment. For example, unless otherwise indicated, methods (300a), (300b), and / or (400) need not be performed in the exact order shown; and similarly, the individual blocks may be performed in parallel rather than sequentially; therefore, elements of methods (300a), (300b), and (400) are referred to herein as “blocks” rather than “steps.”

[0113] Turn attention Figure 22aAt box 301a, a microcatheter device (e.g., microcatheter device 100) is introduced into the target vascular anatomy, such as the target vessel (200, 203, 204, or 205). At box 302a, PEA (109) is injected into the target vascular anatomy until the desired volume of the target vascular anatomy is filled. At box 303a, after injection, at least one electromagnetic wave is emitted towards the PEA disposed in the target vascular anatomy at one or more coagulation wavelengths of the PEA.

[0114] According to some embodiments, before emitting at least one electromagnetic wave at at least one coagulation wavelength, method 300a further includes determining whether the microcatheter device has malfunctioned (e.g., as discussed above). According to some embodiments, this determination includes sensing at least one electromagnetic wave reflected back from the MPW.

[0115] According to some embodiments, method 301a further includes removing the microcatheter from the coagulated PEA and target vascular anatomy after emitting at least one electromagnetic wave at a coagulation wavelength (box 303a). According to some embodiments, removing the microcatheter includes detaching the microcatheter from the coagulated PEA. According to some embodiments, detaching the microcatheter includes activating a photodegradation mechanism.

[0116] According to some embodiments, method 300a further includes determining the solidification state of the PEA. According to some embodiments, this determination is performed in real time or near real time (typically with a delay of less than one second) by emitting at least one electromagnetic wave (box 303a) into the PEA. According to some embodiments, the determination includes detecting at least one electromagnetic wave back-reflected from the PEA disposed in the target vascular anatomy.

[0117] Method 300b Figure 22b The action of box 301a (introducing a microcatheter into the target vascular anatomy) is shared. However, at box 302b, PEA is injected into the target vascular anatomy, and simultaneously (synchronously) at least one electromagnetic wave of one or more coagulation wavelengths is emitted to coagulate the PEA in the pre-cured area or the target vascular anatomy. Optionally, at box 303b, at least one electromagnetic wave is emitted to further coagulate the PEA disposed in the target vascular anatomy. Similar to method 300a, method 300b further includes determining the coagulation state of the PEA. For example, the determination of the coagulation state of the PEA can be performed in real time or near real time by emitting at least one electromagnetic wave to the PEA (boxes 302b and 303b). According to some embodiments, this determination includes detecting at least one electromagnetic wave back-reflected from the PEA disposed in the target vascular anatomy.

[0118] Turning attention back to Figure 17And the various boxes including method (400). Typical uses of microcatheters typically involve navigating the microcatheter to the treatment site using a conventional microguidewire (box 401), which can be further guided by a larger-gauge support catheter. Once the treatment site is reached, digital subtraction angiography is typically used to perform a pre-embolization scan (box 402). Digital subtraction angiography provides local vessel size / diameter, blood flow velocity, downstream vascular structure, and the presence of any critical structures. Based on prior knowledge of the anatomy and observations during digital subtraction angiography, the operator first decides whether to inject PEA via a synergistic or sequential approach, which alters the timing of electromagnetic energy emission relative to the injection timing. Subsequently, the operator can determine the degree of thickening or coagulation required for optimal filling of the treatment site (target vascular anatomy) with PEA based on factors such as those affecting local hydrodynamics (box 403). The operator will then determine and select the correct electromagnetic power output for the desired viscosity (box 404). In the case of the sequential approach, the selected EM power output is nominally zero. The operator injects PEA into the treatment site until it is filled (box 405). Using real-time fluoroscopy or supplemental digital subtraction angiography, the operator can confirm when the treatment site is filled and repeat or continue the injection as needed (box 406). It should be noted that at any point during the injection, the operator can choose to change the electromagnetic power output based on fluoroscopic feedback (boxes 407 and 408). Thus, the operator can initially begin the injection using a sequential method (i.e., without synchronous electromagnetic energy emission during PEA injection) but decide to emit electromagnetic energy midway through the injection to thicken or coagulate subsequently injected PEA. This may occur, for example, if the operator observes excess PEA being flushed away due to high blood flow. Once the treatment site is filled with the desired amount of PEA, the operator decides whether to perform post-injection curing (box 409). If post-injection curing is deemed necessary, the operator can determine and select the appropriate electromagnetic output power and duration. Then, post-injection solidification is performed by activating an electromagnetic energy source while maintaining the microcatheter's position within the blood vessel, allowing the distal end of the microcatheter device to physically contact the deposited PEA, as confirmed by fluorescence fluoroscopy (box 410). It should be noted that several methods for monitoring PEA coagulation are described herein, such as detecting occult waves using an integrated FBG in some embodiments not shown in this flowchart. After PEA coagulation, the operator can slowly retract the microcatheter device from the treatment site and sense for any removal resistance, such as due to adhesion between the coagulated PEA and the microcatheter tip (box 411). If removal of the microcatheter device is difficult (e.g., when pulling the microcatheter device causes PEA displacement), the operator can activate the disengagement mechanism discussed herein (box 412). Once the operator deems it safe, the microcatheter device is retracted and completely removed from the body, ending the treatment (box 413).It should be noted that digital subtraction angiography can be performed at any point during the treatment process (not mentioned in the flowchart) when the operator deems it necessary to further assess the vascular structure at the treatment site and / or confirm the integrity of the deposited PEA. Several fault detection mechanisms may exist throughout the use of the microcatheter, which are monitored but not mentioned in the flowchart. These include, but are not limited to, monitoring catheter rupture via injection force sensing from the syringe pump, and detecting MPW breakage by detecting back-reflected light and its power, polarization state, and wavelength.

[0119] Figure 18a and Figure 18b A configuration according to a non-limiting embodiment is depicted, in which an outlet pressure reducing valve (135) is integrated to controllably pressurize the pre-cured area and restrict the flow of PEA (109). This mechanism can be employed to ensure consistent thickening / solidification of the injected PEA (109) and to limit the accidental release of uncured PEA (109), which could lead to off-target embolism. Figure 18a The configuration of a pre-curing region of a microcatheter device with the outlet valve (135) closed is depicted. The outlet pressure relief valve is configured to open when a predetermined pressure relief (typically from about one-tenth to several hundred PSIs) is reached within the pre-curing region. With the outlet pressure relief valve (135) closed, the flow of PEA (109) within the pre-curing region is halted, allowing a given volume of PEA (109) more time to be exposed to electromagnetic energy (102). Once sufficient thickening or coagulation of the PEA (109) is achieved within the pre-curing region (103), the cured PEA (111) can be released into the target vessel by applying sufficient pressure to open the outlet pressure relief valve (135). The outlet pressure relief valve can be closed again, and the process can be repeated multiple times during treatment.

[0120] Figure 19 An example configuration for diffusing electromagnetic waves (104) through a working cavity (101) is depicted. Diffusing electromagnetic waves (104) is advantageous because it allows for more efficient absorption of the uncured PEA (109) over a controlled distance, regardless of the electromagnetic energy absorption of the PEA, compared to configurations with forward-firing regimes. The working cavity (101) may be doped with a scatterer, or the materials may be selected such that the working cavity scatters the emitted electromagnetic waves (104), thus acting as a light diffuser.

[0121] Figure 20a and Figure 20bA non-limiting configuration of the working cavity (104) is depicted, in which the pre-cured region is widened (103). The widened pre-cured region (137) effectively increases the cross-sectional area and reduces the flow velocity of the uncured PEA (109) under constant flow conditions (e.g., when the injection is driven by an infusion pump). With the reduced flow velocity, the time for electromagnetic waves (104) to be absorbed by the uncured PEA (109) increases, thus allowing for a higher solidification rate. In the case where fully cured PEA (111) is sprayed through the outlet port (113), the widened pre-cured region (137) is designed so that the cured PEA (111) has a desired shape (e.g., a wider diameter). Figure 20a One configuration is shown in which the widened pre-cured region (137) is concentric with the working cavity (101), while the MPW (102) is eccentric. Figure 20b A widened pre-cured region (137) is depicted, the inner diameter of which is concentric with MPW (102).

[0122] and Figure 20a and Figure 20b on the contrary, Figure 21a and Figure 21b A non-restrictive configuration of a pre-cured region (103) with a tapered wall (141) is depicted, resulting in a smaller cross-sectional area at the end. The tapered wall (141) effectively increases the flow resistance within the pre-cured region (103) and pressurizes the pre-cured region, thereby reducing the flow rate of uncured PEA (109) when injection is driven under a constant pressure mechanism (e.g., when performing a steady manual injection). Figure 21a The configuration of the eccentric conical pre-cured region (103) of the MPW (102) is shown, while Figure 21b A conical pre-cured region (103) is depicted, in which the MPW (102) of the conical pre-cured region is concentrically positioned within the pre-cured region (103). Figures 20a to 21b Both illustrated conical designs can help achieve more robust and consistent thickening / coagulation, and reduce the incidence of uncured PEA (109) release that could lead to off-target embolism. The choice of design may depend on non-limiting factors, including whether the injection is volume-controlled or pressure-controlled.

[0123] Figure 23Examples of multiple MPWs, housed within respective channels and terminating at various locations to allow for multiple beam directions, are depicted according to a non-limiting embodiment. In this specific example, one of the MPWs (102) terminates immediately adjacent to a pre-cured region (103), while an additional MPW (142) extends to the tip of the microcatheter device. According to a non-limiting embodiment, either MPW (102) or MPW (142) may be activated individually, or both may be activated simultaneously. To highlight an example use case, an operator may initially wish to perform an injection of PEA while simultaneously coagulating the PEA by emitting electromagnetic energy (104) through the MPW (102), which is positioned to efficiently irradiate the pre-cured region (103). Once the injection is complete and the treatment site is filled, the operator may further wish to perform post-injection curing by emitting electromagnetic energy (143) through the MPW (142) to reinforce the injected PEA, which is positioned to effectively irradiate the intravascular space near the tip of the microcatheter device.

[0124] Those skilled in the art will understand that many alternative implementations and possible modifications exist, and the examples above are merely illustrative of one or more implementations. Therefore, the scope is limited only by the appended claims. explain

[0125] It should also be understood that, for the purposes of this application, the phrase “at least one of X, Y and Z” or “one or more of X, Y and Z” can be interpreted as: only X; only Y; only Z; or any combination of two or more of X, Y and Z (e.g., XYZ, XYY, YZ, ZZ).

[0126] In this application, a component may be described as being "configured" or "capable" of performing one or more functions. Generally, it should be understood that a component configured or capable of performing a function is configured or capable of performing that function, or is adapted to perform that function, or is operable to perform that function, or is otherwise capable of performing that function.

[0127] Furthermore, components in this application may be described as being "operationally connected" to other components, "operationally coupled to" other components, etc. It should be understood that such components are connected or coupled to each other in a manner that performs a certain function. It should also be understood that "connection," "coupling," etc., as used in this application include both direct and indirect connections between components.

[0128] References to "an embodiment," "embodiment," "implementation," "variation," etc., in this application indicate that the described embodiment, implementation, or variation may include a particular aspect, feature, structure, or characteristic, but not all embodiments, implementations, or variations must include that aspect, feature, structure, or characteristic. Furthermore, such phrases may, but do not necessarily, refer to the same embodiment referenced in other parts of the specification. Further, when a particular aspect, feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, the influence or connection of such a module, aspect, feature, structure, or characteristic by other embodiments is within the understanding of those skilled in the art. In other words, any module, element, or feature can be combined with any other element or feature in different embodiments unless there is an obvious or inherent incompatibility or it is explicitly excluded.

[0129] It should also be noted that the claims may be drafted to exclude any optional elements. Thus, this statement is intended to serve as a preliminary basis for the use of exclusive terms (such as “only,” “merely,” etc.) or “negative” restrictions in conjunction with the description of the claim elements. The terms “preferred,” “ideally,” “preferred,” “optionally,” “may,” and similar terms are used to indicate that the item, condition, or step referred to is an optional (non-essential) feature of the invention.

[0130] Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” include plural indicators. The term “and / or” refers to any one, any combination of, or all of the items associated with the term. Those skilled in the art will readily understand the phrase “one or more,” especially when read in its context of use.

[0131] The term "about" can refer to a variation of ±5%, ±10%, ±20%, or ±25% of the specified value. For example, "about 50 percent" in some embodiments can include a variation between 45 percent and 55 percent. For integer ranges, the term "about" can include one or both integers greater than and / or less than the integer at both ends of the range. Unless otherwise stated herein, the term "about" is intended to include values ​​and ranges near the range that are functionally equivalent in relation to the composition or embodiment.

[0132] As those skilled in the art will understand, for any and all purposes, particularly in providing a written description, all ranges described herein also include any and all possible subranges and combinations thereof, as well as the individual values, particularly integer values, that constitute the range. The range includes every specific value, integer, decimal, or identity within that range. Any listed range can be readily identified as sufficiently descriptive and such that the same range can be decomposed into at least two, three, four, five, or ten equal parts. As a non-limiting example, each range discussed herein can be readily decomposed into a lower third, a middle third, and an upper third, etc.

[0133] As those skilled in the art will also understand, all terms such as “up to,” “at least,” “greater than,” “less than,” “more than,” and “or more” include the stated figures, and such terms refer to ranges that can subsequently be broken down into subranges as discussed above. Similarly, all ratios described herein also include all sub-ratios falling within a broader range of ratios.

Claims

1. A microcatheter device, comprising: A working lumen having at least one outlet port at its distal end, the working lumen being configured to deliver an intravascular injection of a photoactivated embolic agent (PEA) to a target vessel via the at least one outlet port; as well as A mechanically protected waveguide (MPW) is operatively connected to the working lumen and configured to emit at least one electromagnetic wave via the at least one outlet port to deliver to the target blood vessel.

2. The apparatus according to claim 1, wherein, The mechanically protected waveguide: It is at least partially embedded in the wall of the working cavity; It is co-extruded into the wall of the working cavity; It is at least partially separated from the working cavity by at least one barrier; The external section connected to the working cavity; Weaved into the braided portion of the microcatheter; and / or It is at least partially located within an enclosed space separate from the working cavity.

3. The apparatus according to claim 1 or claim 2, further comprising: A pre-cured region, located within the microcatheter and near the at least one outlet port, is configured to adjust the viscosity of the PEA prior to its injection into the target blood vessel.

4. The apparatus according to any one of claims 1 to 3, wherein, The mechanical protection waveguide is a multimode optical fiber.

5. The apparatus according to any one of claims 1 to 4, wherein, The working cavity includes biocompatible materials such as nylon, Vestamid, Pebax, and PTFE.

6. The apparatus according to any one of claims 1 to 5, wherein, The mechanical protection waveguide is configured to transmit the electromagnetic waves to the target blood vessel and / or the pre-cured region.

7. The apparatus according to any one of claims 1 to 6, further comprising: At least one beamforming element.

8. The apparatus according to claim 7, wherein, The at least one beamforming element includes one or more optical components, such as one or more of a lens, diffuser, filter, reflector, and mask.

9. The apparatus according to claim 7 or claim 8, wherein, The at least one beamforming element is configured to provide at least one radially emitted beam to be delivered to the pre-cured area.

10. The apparatus according to any one of claims 7 to 9, further comprising: At least one transmit beam, wherein the at least one transmit beam comprises: The first beam, the first beam being directed at the target blood vessel, and The second beam is directed at the pre-cured area.

11. The apparatus according to any one of claims 7 to 10, wherein, The at least one beamforming element includes a plurality of beamforming elements configured to provide a plurality of radial beams in a plurality of directions.

12. The apparatus according to any one of claims 1 to 11, wherein, The mechanical protection waveguide includes an FBG.

13. The apparatus according to claim 12, wherein, The FBG is tuned to a secondary wavelength and configured to back-reflect light with a second wavelength.

14. The apparatus according to any one of claims 1 to 11, further comprising: A fiber Bragg grating (FBG) element configured to selectively propagate light of a first wavelength in a first direction and light of a second wavelength in a second direction based on the frequency of the electromagnetic wave.

15. The apparatus according to claim 14, wherein, The first direction is toward the at least one outlet port, and the second direction is a radial direction.

16. The apparatus according to any one of claims 1 to 13, further comprising: A detachment mechanism configured to detach the solidified PEA from the distal end of the microcatheter.

17. The apparatus according to claim 16, wherein, The PEA is detached by emitting electromagnetic waves of a predetermined wavelength through the MPW, the electromagnetic waves being configured to photodegrade the cross-linked PEA.

18. The apparatus according to claim 16, wherein, The detachment mechanism includes a hydrophobic or superhydrophobic coating applied to the outer surface of the distal end near the at least one outlet port.

19. The apparatus according to any one of claims 1 to 18, wherein, At least a portion of the distal end includes a reflective coating and / or reflective material and is configured to reflect excess light emitted radially outward in a radially inward direction.

20. The apparatus according to any one of claims 2 to 19, further comprising: An optical cavity, which is operatively connected to the pre-cured area.

21. The apparatus according to any one of claims 1 to 20, wherein, The mechanical protection waveguide includes an optical fiber element configured to guide at least one evanescent wave into physical contact with the PEA.

22. The apparatus according to any one of claims 1 to 21, wherein, It can detect optical refractive index in PEA.

23. The apparatus of claim 22, further comprising: A testing mechanism configured to detect changes in the optical refractive index of the medium surrounding the mechanically protected waveguide.

24. The apparatus according to any one of claims 1 to 23, further comprising: A power injector configured to supply fluid to the outlet port at a predetermined pressure and to determine changes in the back pressure of the fluid.

25. The apparatus according to claim 24, wherein, The determination of the change in back pressure of the fluid is performed in real time.

26. The apparatus according to any one of claims 1 to 25, further comprising: It can detach from the end.

27. The apparatus according to claim 26, wherein, The detachable end is configured to dissolve within the target blood vessel within a predetermined time period.

28. The apparatus according to claim 27, wherein, The detachable end is biocompatible.

29. The apparatus according to any one of claims 3 to 28, wherein, The distal end of the MPW floats freely within the pre-cured area.

30. The apparatus according to any one of claims 1 to 29, further comprising: At least one valve mechanism.

31. The apparatus according to any one of claims 1 to 30, wherein, The distal end of the working cavity is tapered.

32. The apparatus according to claim 31, wherein, The taper dimensions are determined to provide the desired flow velocity to the target blood vessel via a PEA.

33. The apparatus according to any one of claims 1 to 32, further comprising: A solid component inserted into the working cavity.

34. The apparatus according to any one of claims 3 to 33, further comprising: At least one additional lining is provided within the pre-cured area, the at least one additional lining being configured to restrict the adhesion of the cured PEA to the inner and / or outer surfaces of the working cavity.

35. A method for endovascular embolization, the method comprising: Introduce the microcatheter device according to any one of claims 1 to 28 into the target blood vessel; The photoactivated embolizing agent (PEA) is injected into the target vessel until the desired volume of the target vessel is filled; and Following or simultaneously with the injection, electromagnetic waves are emitted into the PEA located in the target blood vessel as a coagulation wave.

36. The method of claim 35, wherein: The emission includes emitting the electromagnetic waves into the pre-cured area.

37. The method according to claim 35 or 36, wherein: Before emitting the electromagnetic wave at the coagulation wavelength, determine whether the microcatheter device has malfunctioned.

38. The method according to claim 37, wherein, Determining whether the microcatheter device has malfunctioned includes sensing at least one electromagnetic wave reflected from the back of the PEA.

39. The method according to any one of claims 35 to 38, further comprising: After emitting the electromagnetic wave at the coagulation wavelength, the microcatheter is removed from the coagulated PEA and the target vessel.

40. The method according to claim 39, wherein, Removing the microcatheter involves detaching the microcatheter from the coagulated PEA.

41. The method according to any one of claims 35 to 40, further comprising: Determine the solidification state of the PEA.

42. The method according to claim 41, wherein, The determination is performed in real time or near real time.

43. The method according to claim 41 or 42, wherein, The determination includes detecting at least one electromagnetic wave reflected back from the PEA disposed in the target blood vessel.

44. The method of claim 40, wherein, Disengaging the microcatheter includes activating the photodegradation mechanism.

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