Catheter including a radiopaque expandable member

#This disclosure relates to a medical catheter.

#A medical catheter defining at least one lumen has been proposed for use with various medical procedures. For example, in some cases, a medical catheter may be used to access and treat defects in blood vessels, such as, but not limited to, lesions or occlusions in blood vessels.

#This disclosure describes example catheters including an elongated body and an expandable member at a distal portion of the elongated body and defining at least part of a distal tip of the catheter. The expandable member is configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of a patient, e.g., to engage a thrombus. The expandable member is formed from materials that enable a distal tip of the catheter to be radiopaque without the addition of a separate radiopaque marker (e.g., a solid metal ring of radiopaque material separate from and connected to the elongated body) at the distal tip of the catheter, e.g., proximal to the expandable member. A solid metal radiopaque marker band may contribute to the overall stiffness of a distal tip of a catheter. Forming the expandable member from a radiopaque material may enable the solid metal radiopaque marker to be eliminated from the distal tip of the catheter, thereby enabling the distal tip of the catheter to be more flexible. In addition, because the expandable member is formed from a radiopaque material, a longer extent of the distal tip of the catheter may be visible under fluoroscopy or x-ray imaging. This may provide a clinician with a better indication of a location of the distal tip within a patient.

#FIG. 1 is a conceptual side view of an example catheter, which includes an elongated body and an expandable member at a distal portion of the elongated body.

#FIG. 2 is a conceptual cross-sectional view of an example of the distal tip of the catheter of FIG. 1, including the distal portion of the elongated body and the expandable member, where the cross-section is taken through a center of the catheter and along a longitudinal axis.

#FIG. 3 is a conceptual cross-sectional view of another example of the distal tip of the catheter of FIG. 1, where the cross-section is taken through a center of the catheter and along a longitudinal axis.

#The disclosure describes a medical device, referred to herein as a “catheter,” including an expandable member configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of a patient, e.g., to engage with a thrombus to facilitate aspiration of the thrombus (or other material or object(s) to be removed, such as a plaque or foreign body). Some catheters include a distinct radiopaque marker band (e.g., a solid metal ring) near a distal tip of the catheter, which may facilitate placement of the catheter via fluoroscopic imaging. This radiopaque marker band may also contribute to an overall (e.g., excessive) stiffness of the distal tip of the catheter, which may adversely impact navigability of the catheter to distal sites in the vasculature of a patient. According to the examples of this disclosure, the expandable members described herein can be integrally formed from one or more materials that enable a distal tip or portion of the catheter to be radiopaque without the addition of a separate, more-rigid radiopaque marker band (e.g., a solid metal radiopaque marker band), thereby improving the flexibility of the distal tip and improving the navigability of the catheter. In addition, because a length of the expandable member is formed from a radiopaque material as compared to a separate, smaller or shorter (as measured in a direction parallel to a longitudinal axis of the catheter) radiopaque marker band, a longer portion of the distal tip or distal portion of the catheter (e.g., about 1 centimeter to about 10 centimeters) may be visible under fluoroscopy or x-ray imaging, thereby providing a clinician with a better indication of a location of the distal tip or distal portion within the vasculature of the patient.

#Example catheters in accordance with this disclosure include a relatively flexible elongated body configured to be navigated through vasculature of a patient, e.g., tortuous vasculature in a brain of the patient. The elongated body may include a plurality of concentric layers, such as an inner liner, an outer jacket, and a structural support member (e.g., a coil, braid, and/or hypotube) positioned between at least a portion of the inner liner and outer jacket. A distal tip or distal portion of the catheter includes an expandable member, such as an expandable stent-like structure or an expandable braid, positioned distal to a distal portion of the elongated body. In some examples, the expandable member is distinct from, but mechanically coupled to, the distal portion of the elongated body. In other examples, the expandable member is integrally formed with (e.g., laminated with and/or forming a distal extension of) the distal portion of the elongated body. The expandable member is configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of the patient. This may enable, for example, the expandable member to engage with a thrombus, such as a clot, embolism, or other material such as plaques or foreign bodies during an aspiration procedure, such as, but not limited to, a medical procedure using A Direct Aspiration first Pass Technique (ADAPT) for acute stroke thrombectomy.

#The expandable member may help improve aspiration of the thrombus into the catheter by providing a relatively large luminal diameter (and therefore exert a larger aspiration force against the thrombus or other material to be removed) and interior space for the thrombus to engage with the catheter compared to examples in which an otherwise similar catheter does not include an expandable member. For example, such a catheter that does not include an expandable member may have limited radial expansion due to a structural support member that extends to the distal end of the catheter, and may thus make it harder to aspirate a thrombus (e.g., due to a smaller cross-sectional dimension of the distal end of the catheter). The expandable member may overcome such radial expansion limitations, thereby increasing thrombus engagement, reducing the amount of time required for revascularization, and increasing revascularization success rates for various procedures, as compared to similar procedures performed using catheters that do not include an expandable member to engage a thrombus.