Patent Description:
Healthy leg veins contain valves that allow blood to move in one direction from the lower limbs toward the heart. These valves open when blood is flowing toward the heart, and close to prevent venous reflux, or the backward flow of blood. When veins weaken and become enlarged, their valves cannot close properly, which can lead to venous reflux and impaired drainage of venous blood from the legs, which may be referred to as venous insufficiency. Venous reflux is most common in the superficial veins. The largest superficial vein is the great saphenous vein (GSV), which runs from the top of the foot to the groin, where it originates at a deep vein.

Factors that may contribute to venous reflux disease include female gender, heredity, obesity, lack of physical activity, multiple pregnancies, age, past history of blood clots in the legs, and professions that involve long periods of standing. According to population studies, the prevalence of visible tortuous varicose veins, a common indicator of venous reflux disease, is up to <NUM>% for adult men and <NUM>% for adult women. A clinical registry of over <NUM>,<NUM> patients shows that the average age of patients treated for venous reflux is <NUM> and over <NUM>% of the patients are women.

Venous reflux may be treated with non-invasive methods in the greater saphenous vein. Treatment modalities include radiofrequency (RF) ablation, laser endothermal ablation, and sclerotherapy, including foam sclerotherapy. One method also includes delivering an adhesive into the GSV to close off the symptomatic vein. In such adhesive treatments, the adhesive typically is taken from a sealed vial into a syringe before injected through a catheter and into the GSV. <CIT> discloses a catheter assembly. <CIT> discloses a delivery system and method. <CIT> discloses a catheter.

In some aspects, this disclosure describes example medical assemblies, devices, systems, and techniques for delivery of a medical fluid, such as a medical adhesive, to a patient. In one example, a medical assembly is configured to deliver a medical adhesive to a hollow anatomical structure (e.g., a structure such as a blood vessel that is constructed to contain a fluid) to reduce blood flow or fully close the hollow anatomical structure. This closure of the hollow anatomical structure may be beneficial for treating various conditions, such as venous reflux or venous insufficiency in a superficial or deep vein of a patient. The medical assemblies described herein may be configured to deliver one or more boluses of a medical adhesive to respective locations within a hollow anatomical structure in order to seal the structure.

The invention provides a medical assembly according to claims <NUM> and <NUM>. The medical assembly includes a flexible catheter and a shaft (e.g., a mandrel) configured to be inserted within a lumen of the flexible catheter. The lumen of the flexible catheter is pre-filled with a volume of medical adhesive. Once the flexible catheter is positioned at a target site within a hollow anatomical structure of the patient, a clinician may insert the shaft into the flexible catheter to force the medical adhesive out of the distal end of the flexible catheter and into the hollow anatomical structure for closure. In another example, the clinician may insert a pre-filled cartridge containing the medical adhesive into the lumen of the flexible catheter. Clinician insertion of the shaft into the flexible catheter may puncture through the proximal end of the pre-filled cartridge and force the medical adhesive out of the distal end of the pre-filled cartridge and out of a distal opening of the flexible catheter. In some examples, the flexible catheter may include a side opening configured to receive a guidewire that facilitates navigation of the flexible catheter to the target location within the hollow anatomical structure of the patient.

The medical assembly includes a flexible catheter configured to be disposed within a hollow anatomical structure of a patient, wherein the flexible catheter defines a lumen having a lumen cross-sectional dimension and a distal opening of the lumen, and wherein the lumen is configured to contain a volume of medical adhesive, and a shaft defining a shaft cross-sectional dimension smaller than the lumen cross-sectional dimension of the lumen, wherein advancement of the shaft through at least a portion of the lumen forces at least a portion of the volume of medical adhesive out of the distal opening of the lumen.

In another example, a method includes navigating a distal end of a flexible catheter to a target location within a hollow anatomical structure of a patient, wherein the flexible catheter defines a lumen having a lumen cross-sectional dimension, and a distal opening of the lumen, and wherein the lumen is configured to contain a volume of medical adhesive, and advancing a shaft through at least a portion of the lumen to force at least a portion of the volume of the medical adhesive out of the distal opening of the lumen, wherein the shaft defines a shaft cross-sectional dimension smaller than the lumen cross-sectional dimension of the lumen.

In another example, a medical assembly includes a flexible catheter configured to be disposed within a hollow anatomical structure of a patient, wherein the flexible catheter defines a lumen having a lumen cross-sectional dimension and a distal opening of the lumen, the lumen cross-sectional dimension comprising a range of approximately <NUM> to approximately <NUM>, the flexible catheter comprises a reinforced section comprising at least one of a coil or a braid within a wall of the flexible catheter, and the lumen is configured to contain a volume of medical adhesive, and a shaft defining a shaft cross-sectional dimension smaller than the lumen cross-sectional dimension, wherein advancement of the shaft through at least a portion of the lumen forces at least a portion of the volume of medical adhesive out of the distal opening of the lumen of the flexible catheter, wherein the volume of the medical adhesive is within a range from approximately <NUM> to approximately <NUM>.

Other features, objects, and advantages of examples according to this disclosure will be apparent from the description and drawings, and from the claims.

This disclosure describes medical assemblies, devices, systems, and techniques related to delivering a medical fluid to a hollow anatomical structure (e.g., a vein or an artery) of a patient. Venous reflux or venous insufficiency is a condition in which valves of a vein no longer close properly and blood is able to flow backward within the vein (e.g., a greater saphenous vein or perforator vein). A treatment for venous reflux may include closure or removal of the vein or veins subject to the venous reflux. One example treatment may include delivering a medical adhesive to the vein such that the medical adhesive causes the vein to close. Once the medical adhesive cures, the introduction of adhesive prevents blood from passing through the vein. After the vein is closed, blood can reroute to other veins without compromising systemic blood flow.

An example method for delivering the medical adhesive to the vein may include use of an injector gun, a syringe, and a catheter. The medical adhesive may be stored in a container (e.g., a vial). A clinician may load the syringe with some or all of the medical adhesive contained within the vial. The clinician can then attach the catheter to the syringe, prime the catheter with the medical adhesive, insert the distal end of the catheter into the target vein, and attach the syringe to an injector gun. When the distal end of the catheter is at the target location within the vein, the clinician can actuate the injector gun which depresses the plunger of the syringe and delivers a bolus of the medical adhesive out of the distal end of the catheter. The clinician may withdraw the catheter a short distance one or more times and deliver additional respective boluses of the medical adhesive to other locations within the vein in order to achieve a complete closure of the vein.

In some examples, the medical adhesive may have a viscosity similar to honey, such as between approximately <NUM>,<NUM> centipoise (cps) and <NUM>,<NUM> cps. In some commercial adhesives, the viscosity is between <NUM>,<NUM> and <NUM>,<NUM> cps. This viscosity of the medical adhesive may provide some advantages in delivery to the vein, such as the ability to displace blood and a resistance to flowing away from the delivery location within the vein. Due to the relatively higher viscosity of the medical adhesive, the injector gun typically provides a force multiplier to enable the clinician to more easily deliver the medical adhesive from the syringe. Thus, the system requires a higher force than may be desirable to dispense the viscous medical adhesive from the syringe and through the catheter. Although the syringe and injector gun provide an effective delivery system, the system set up includes several steps prior to the procedure, which extends the procedure time and may be messy.

Further, a clinician may attempt to use portions of the system, such as the syringe and medical adhesive, for the treatment of other patients, which may not be efficacious and potentially hazardous to the second patient.

In the above described method of delivering an adhesive into the GSV to close off the symptomatic vein, there may be some areas for improvement to the adhesive delivery. For example, the adhesive typically is taken from a sealed vial into a syringe, which may be time consuming and/or messy. Further, the entire length of the catheter must be primed with adhesive before adhesive may be delivered for treatment, which may also be time consuming, may waste adhesive, and may require large amounts of force to deliver depending on the viscosity of the adhesive. For at least these reasons, a system which enables a catheter to be preloaded with adhesive may be beneficial when compared to obtaining the adhesive from a sealed vial for the procedure.

Systems, devices, and techniques described herein may reduce the complexity of medical fluid delivery and promote increased patient safety. In some examples, a medical assembly may include a flexible catheter and a shaft (e.g., a mandrel) configured to be inserted within a lumen of the flexible catheter and force the medical fluid (e.g., a medical adhesive) out of a distal opening of the flexible catheter. In one example, the flexible catheter is pre-filled with a volume of medical adhesive. For example, a manufacturer may fill the flexible catheter at a manufacturing facility and store the medical adhesive within the flexible catheter such that the clinician does not need to prime the flexible catheter or otherwise transfer the medical adhesive from a storage container to the flexible catheter prior to the treatment procedure. Once the flexible catheter is inserted into a desired vein (or other anatomical structure) of the patient, the physician inserts the shaft into a proximal opening of the flexible catheter and advances the shaft through the lumen of the flexible catheter to force the medical adhesive out of the distal opening of the flexible catheter and into the vein.

In another example, the system is a cartridge-based catheter delivery system that includes a pre-filled cartridge containing a volume of the medical adhesive, separate from the flexible catheter. In one specific example, a clinician inserts the pre-filled cartridge containing the medical adhesive into the lumen of the flexible catheter. In another specific example, the pre-filled cartridge is preloaded in the lumen of the flexible catheter during manufacturing. Then, the clinician may insert the distal end of the shaft into the lumen of the flexible catheter to puncture through the proximal end of the pre-filled cartridge and force the medical adhesive out of the distal end of the pre-filled cartridge and out of the distal opening of the flexible catheter. In this manner, the shaft is advanced through the lumen of the pre-filled cartridge until the clinician has dispensed the desired amount of medical adhesive. If more medical adhesive is required than is provided in a single pre-filled cartridge, then the prefilled cartridge may be removable from the flexible catheter and another pre-filled cartridge loaded with more medical adhesive can again be loaded into the flexible catheter. In one example, the pre-filled cartridge is filled and sealed during manufacturing. Thus, the pre-filled cartridge is provided to the clinician pre-filled and ready to be used. In another example, the cartridge is filled by the clinician (or other practitioner working with the clinician) such that the cartridge is pre-filled prior to the procedure.

The pre-filled catheter delivery system or pre-filled cartridge-based catheter delivery system may thus be configured to deliver medical adhesive without a syringe or an injector gun, which may help decrease time and cost associated with the medical procedure. Since the diameter of the flexible catheter is smaller than a syringe, less force may be required to dispense the medical adhesive from the flexible catheter compared to the syringe. These systems may also reduce the likelihood that medical adhesive would be reused for another patient because the medical adhesive is retained within the catheter that was already inserted within a patient. Reuse of the medical adhesive may be avoided to prevent the spread of disease between patients, or ensure the adhesive is efficacious, for example. The pre-filled catheter delivery system may simplify procedure setup because the medical adhesive does not need to be transferred to the flexible catheter by the clinician. The cartridge-based catheter delivery system may include a step of inserting the pre-filled cartridge (which includes the medical adhesive) into the flexible catheter prior to the procedure. The clinician may have the option of inserting another pre-filled cartridge containing additional medical adhesive if necessary to complete the closure procedure on the patient's vein.

Any of these flexible catheter delivery systems described herein may also be configured to facilitate catheter delivery using a rapid exchange guide wire. For example, the flexible catheter may include a side opening configured to receive a guidewire that facilitates navigation of the flexible catheter to the target location within the hollow anatomical structure (e.g., a vein) of the patient. Once in place, the guidewire may be removed from the lumen of the flexible catheter via the side opening. In some examples, advancement of the medical adhesive from a location proximal to the side opening may force a flap within the flexible catheter to close off the side opening to the catheter and prevent medical adhesive from exiting through the side opening. In other examples, advancement of the medical adhesive-filled cartridge distally passed the side opening may result in the pre-filled cartridge closing off the side opening in the flexible catheter that leads to the lumen defined by the flexible catheter. In other examples, the flexible catheter may have an "over-the-wire" configuration that includes a separate guide wire lumen that runs the entire length of the catheter parallel to the lumen that receives the pre-filled cartridge. In this example, the side opening and flap may not be provided.

Although the catheter delivery systems described herein are primarily described with reference to delivering a medical adhesive to a vein of a patient for purposes of treating venous reflux, these systems may be directed to treatment of other conditions or delivery of medical fluid to other locations within a patient. For example, the catheter delivery systems described herein may be configured to deliver wound closure adhesives to an injured hollow anatomical structure (e.g., a blood vessel or portion of a gastrointestinal tract) or other tissue. As another example, the catheter delivery systems described herein may configured to deliver a medical fluid, such as drug to a desired tissue of the patient. Other example uses of the catheter delivery systems described herein may include delivery of an adhesive to a specific location to interrupt blood flow, such as an arterial embolic to stop blood flow to a tumor. Although human structures are described herein, other animal species may be treated using the medical assemblies and techniques described herein.

<FIG>, <FIG>, <FIG>, <FIG>, and <FIG> are schematic views of an example procedure for delivering a vein-occluding substance to a patient. As shown in <FIG>, medical assembly <NUM> includes a flexible catheter <NUM>, with a proximal end 14A and a distal end 14B, and a shaft <NUM>. The flexible catheter <NUM> has been inserted into a vein <NUM> of the patient. The vein <NUM> may be a greater saphenous vein in some examples, but the vein <NUM> may be any superficial, deep, or perforator vein in other examples. The vein <NUM> includes an inferior portion <NUM> and a superior portion <NUM>. The shaft <NUM> (e.g., a mandrel) is inserted into the proximal end 14A of the flexible catheter <NUM> in order to force a portion of a medical adhesive (e.g., medical adhesive <NUM> shown in <FIG>) out of the distal end 14B of the flexible catheter <NUM>. The shaft <NUM> may be inserted by the clinician or may be inserted during manufacturing and sent to the clinician pre-inserted.

The flexible catheter <NUM> is configured to be disposed within a hollow anatomical structure (e.g., the vein <NUM>) of a patient. The flexible catheter <NUM> is an elongated structure (e.g., a tubular body) defining at least one lumen having a lumen cross-sectional dimension (e.g., a diameter in the case of a cylinder), a proximal opening of the lumen, and a distal opening of the lumen. The lumen of the flexible catheter <NUM> is configured to contain a volume of medical adhesive, either directly or via another structure (e.g., a pre-filled cartridge or other container) placed within the flexible catheter <NUM>. The shaft <NUM> (e.g., a mandrel or other pushing member) defines a shaft cross-sectional dimension smaller than the lumen cross-sectional dimension of the lumen of the flexible catheter <NUM>.

The shaft <NUM> may be an elongated structure that is axially rigid to resist compression and laterally flexible to follow curvature of the flexible catheter <NUM> and patient vasculature. In some examples, the shaft <NUM> may be constructed of a metal or metal alloy, such as medical grade stainless steel, a titanium alloy (e.g., nitinol), or any other such metal. In other examples, the shaft <NUM> may be constructed of a polymer or combination of polymers. The shaft <NUM> may have a cross-sectional shape that is at least one of circular, oval, a rounded square, or other shape. In some examples, the cross-sectional shape of the shaft <NUM> may be selected to correspond to the cross-sectional shape of the lumen of the flexible catheter <NUM> in some examples.

Advancement of the shaft <NUM> through at least a portion of the lumen of the flexible catheter <NUM> may force at least a portion of the volume of medical adhesive out of the distal opening of the lumen of the flexible catheter <NUM>. For example, a user may apply a force to the shaft <NUM> in the distal direction, and the shaft <NUM> may transfer that force to increase the pressure of the volume of medical adhesive within the lumen of the flexible catheter <NUM>. That increased pressure will cause at least a portion of the volume of the medical adhesive to flow distally through the lumen and eventually out of the distal end 14B of the flexible catheter <NUM>. The shaft <NUM> may include a handle on a proximal end that facilitates handling from a human hand. In addition, the flexible catheter <NUM> may include one or more structural features near the proximal end 14A that enables a user to hold on to the flexible catheter <NUM> while the shaft <NUM> is inserted and/or advanced into the flexible catheter <NUM>. In some examples, the flexible catheter <NUM> may be inserted within a lumen defined by a guide catheter. The guide catheter may be initially inserted within the vein <NUM> and facilitate navigation of the flexible catheter <NUM> to the vein <NUM>.

In some cases, a clinician may use an imaging tool such as an ultrasound transducer <NUM> to assist in guiding the flexible catheter <NUM> to the target location(s) that will receive the medical adhesive. The ultrasound transducer <NUM> may be multifunctional. For example, the ultrasound transducer <NUM> may include one or more ultrasound sensors used to generate an image that helps a clinician guide the catheter <NUM> (or another device, such as a guide catheter or a guidewire) through vasculature of a patient, may serve as a compression element to the vein <NUM> after a bolus of medical adhesive is delivered in the vein <NUM>, and/or identifying areas in the interior of the vein <NUM> that may need further occlusion or closure. In some examples, the ultrasound transducer <NUM> can be placed into contact with an external surface of a patient's skin prior to placing the flexible catheter <NUM> or any other devices (e.g., an introducer catheter or guidewire through vessel <NUM>). The ultrasound transducer <NUM> can assist in generating images to help guide one or more catheters or guide devices to the target site or sites where a vein-occluding substance (e.g., a medical adhesive) will be introduced. In some examples, the ultrasound transducer <NUM> can also serve as a compression element prior to, during or after introducing the medical adhesive to assist in closure of the vein <NUM>. By serving as a compression element, the ultrasound transducer <NUM> can help to flatten and/or reduce the size of the vein <NUM>. In some examples, the ultrasound transducer <NUM> can include a Doppler flow detection capability, and help to identify areas in the interior of the vein <NUM> that may need further closure or occlusion and thus, further application of a vein-occluding substance.

In some examples, the flexible catheter <NUM> may include one or more features that promote visualization of one or more portions of the flexible catheter <NUM> under ultrasound visualization with the ultrasound transducer <NUM>. For example, the flexible catheter <NUM> may include one or more echogenic portions at the distal portion of the flexible catheter <NUM>. The echogenic portion may include one or more cavities defined in the wall of the flexible catheter <NUM>. These cavities may be disposed circumferentially, axially, and/or or radially within the wall of the flexible catheter <NUM>. The cavities may include a gas (e.g., air or nitrogen), a solid material (e.g., a metal alloy), or some other material that can be differentiated from other anatomical structures or fluids within the patient.

As shown in <FIG>, advancement of the shaft <NUM> in the (distal) direction of arrow <NUM> may apply a force to the volume of medical adhesive contained within the flexible catheter <NUM> that displaces the bolus <NUM> of the medical adhesive out of distal end 14B of the flexible catheter <NUM>. In some examples, the shaft <NUM> may include one or more markings along the length of the shaft <NUM> that indicate the volume of medical adhesive delivered by advancement of the shaft <NUM>. For example, each marking along the length of the shaft <NUM> may specify a single bolus or some specified volume, such as <NUM> milliliters (mL) or some other volume increment. In this manner, the user may use the markings along the shaft <NUM> in relation to the proximal opening of the flexible catheter <NUM> as a measurement of the amount of volume of the medical adhesive delivered during advancement of the shaft <NUM>.

In the example of <FIG>, the bolus <NUM> of the medical adhesive has been delivered into the vein <NUM> and the clinician has proximally withdrawn the flexible catheter <NUM> from the site at which the bolus <NUM> was delivered. Once the flexible catheter <NUM> is removed from the area containing the bolus <NUM>, the clinician may apply pressure to that portion of the vein <NUM> with the medical adhesive of the bolus <NUM>. For example, as shown in <FIG>, an optional compression element, e.g., an operator's hand <NUM>, a sequential compression device, or the ultrasound transducer <NUM> can be used to apply pressure on the external surface of the patient's body and compress the interior walls of the vein <NUM>. The optional compression element can be used to compress portions of the vessel prior to, during or after the introduction of the medical adhesive. When the compression element compresses portions of the vein <NUM> during or after the introduction of the bolus <NUM>, the vessel is compressed against the bolus <NUM>, as shown in <FIG>. This compression assists in occlusion as well as collapse of the vein <NUM> in order to coapt the vessel walls. In some examples, as additional portions of the vessel are treated with the medical adhesive, the target regions of the vein <NUM> can be compressed immediately following, or no more than about <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minute, <NUM> seconds, <NUM> seconds, or less following injection of the medical adhesive.

After delivering of the bolus <NUM> and application of pressure to the site containing the bolus <NUM>, the clinician may withdraw the flexible catheter <NUM> to a new location within the vein <NUM> and repeat the process shown in <FIG> in order to deliver another bolus of the medical adhesive to the new location within the vein <NUM>. In some examples, different locations for delivery of the medical adhesive may be spaced apart between approximately <NUM> centimeters (cm) and approximately <NUM> along the length of the vein <NUM>. In other examples, the distal end 14B of the flexible catheter <NUM> may be moved between approximately <NUM>% to approximately <NUM>% of a total length of the vein <NUM> to be treated for each location to receive a bolus of the medical adhesive. In some examples, each site for treatment may be between approximately <NUM>% to approximately <NUM>% of the total length of the treatment site for the vein <NUM>. In some examples, the total treatment site of the vein <NUM> may have a length between approximately <NUM> and approximately <NUM>, or between approximately <NUM> and approximately <NUM> in some examples.

As shown in <FIG>, multiple boluses of the medical adhesive have been delivered to the vein <NUM> in order to create an occluded portion <NUM> of the vein <NUM>. The occluded portion <NUM> may include medical adhesive that has been delivered from the catheter <NUM> and into the vein <NUM> and adhered to the walls of the vein <NUM>. In some examples, the occluded portion <NUM> may include a continuous length of medical adhesive caused by multiple delivered boluses. In other examples, the occluded portion <NUM> may include multiple separate areas of the vein <NUM> that have been coapted by the medical adhesive. After the medical adhesive is delivered, the clinician may remove the flexible catheter <NUM> and the shaft <NUM> from the vein <NUM> and the patient.

In some examples, such as the examples of <FIG>, the lumen of the flexible catheter <NUM> is pre-filled (e.g., filled by a manufacturer as opposed to being filled by the clinician) with a volume of the medical adhesive. The volume of medical adhesive pre-filled in the lumen may be sufficient to treat an entire length of the vein <NUM>. By pre-filling the flexible catheter <NUM> with the volume of the medical adhesive, a user will not need to add the medical adhesive to the flexible catheter <NUM> prior to performing the procedure on the patient. In some examples, the proximal end 14A of the flexible catheter <NUM> may be sealed or a plug may be inserted proximal to the medical adhesive in the lumen in order to seal the lumen of the flexible catheter <NUM> and prevent the medical adhesive from curing when stored within the flexible catheter <NUM>. In addition, a seal, membrane, or cap may be provided on the distal end 14B of the flexible catheter <NUM> to preserve the medical adhesive in the uncured stated while stored within the flexible catheter <NUM>. A user may remove the proximal or distal seal prior to use, or in some examples, advancement of the shaft <NUM> may puncture or displace the proximal seal, while pressure caused by the advancement of the shaft <NUM> may rupture the distal seal. In this manner, the device or mechanism provided to seal the medical adhesive within the flexible catheter <NUM> may be configured to be removed, displaced, or ruptured by advancement of the shaft <NUM> within the lumen of the catheter <NUM>.

When the lumen of the flexible catheter <NUM> is pre-filled with a volume of medical adhesive, the cross-sectional dimension of the shaft <NUM> may be sized to correspond with the cross-sectional dimension of the lumen of the flexible catheter <NUM>. For example, the cross-sectional dimension (e.g., a diameter for a cylindrical shaft) of the shaft <NUM> may be slightly smaller than the cross-sectional dimension of the lumen of the flexible catheter <NUM> to enable the shaft <NUM> to move within the lumen but prevent much, if any, medical adhesive from passing between the shaft <NUM> and the wall of the flexible catheter <NUM>. Therefore, the diameter of the shaft <NUM> may not be exactly the same as the diameter of the lumen defined by the flexible catheter <NUM>. In some examples, a distal end of the shaft <NUM> may include, be attached to, or otherwise be in contact with a movable plug that separates the medical adhesive from the shaft <NUM>. In this manner, the shaft <NUM> may force the movable plug against the medical adhesive to force the medical adhesive out of the distal end 14B of the flexible catheter <NUM>.

In some examples, the flexible catheter <NUM> may be configured to be inserted into the vein <NUM> or other hallow anatomical structure over a guidewire. The guidewire may first be inserted into the vein <NUM> and then the flexible catheter <NUM> may be inserted over the guidewire until the distal end 14B is located at the desired location. When the flexible catheter <NUM> is pre-filled with the medical adhesive, the guidewire must be able to pass out from the lumen of the flexible catheter <NUM> and through the wall of the flexible catheter <NUM> at a location distal to where the medical adhesive is contained within the flexible catheter <NUM>. In some examples, the flexible catheter <NUM> may define a side opening in the wall of flexible catheter at a location distal to the volume of the medical adhesive pre-filled within the lumen, the side opening being sized to accept a guidewire. The wall of the flexible catheter <NUM> may define a side opening that is circular, ovular, square, rectangular, or any other shape that is configured to receive the guidewire.

A structure, such as a flap, may be disposed within the flexible catheter <NUM> to retain the medical adhesive proximal to the side opening when the guidewire is inserted within the lumen of the flexile catheter <NUM>. Once the guidewire is removed, the structure may be moved to enable delivery of the medical adhesive through the lumen of the catheter <NUM> and distal to the structure. For example, the flexible catheter <NUM> may include a flap that is configured to move between a first position that retains the volume of the medical adhesive proximal to the side opening and a second position that closes the side opening from the lumen and enables the adhesive to move past the side opening. In some examples, advancement of the medical adhesive distally within the lumen of the flexible catheter <NUM> (e.g., via advancement of the shaft <NUM>) forces the flap from the first position to the second position. In the second position, the flap enables the medical adhesive to flow through the lumen and distal to the side opening.

In other examples, such as the examples of <FIG>, the lumen of the flexible catheter <NUM> is configured to accept a pre-filled cartridge filled with the volume of the medical adhesive. The pre-filled cartridge is configured to be inserted at least partially into the lumen of the flexible catheter <NUM>. The pre-filled cartridge may define an outer diameter that corresponds to the lumen cross-sectional dimension of the lumen of the flexible catheter <NUM>. The outer diameter of the pre-filled cartridge may be slightly smaller than the diameter of the lumen of the flexible catheter in order to enable the pre-filled cartridge to slide within the lumen. In some examples, the cross-sectional dimension of the shaft <NUM> is sized to enable the shaft <NUM> to slide within the lumen defined by walls of the pre-filled cartridge. In these examples, advancement of a distal end of the shaft <NUM> through a proximal portion of the pre-filled cartridge forces at least a portion of the medical adhesive out of the distal end of the pre-filled cartridge and out of the distal opening of the lumen of the flexible catheter <NUM>. In other examples, the shaft <NUM> may contact and compress the sidewall of the pre-filled cartridge as the shaft <NUM> is advanced distally within the lumen of the flexible catheter <NUM> in order to expel the medical adhesive out of the pre-filled cartridge and the distal opening of the flexible catheter <NUM>.

In some examples, the flexible catheter <NUM> that is configured to accept the pre-filled cartridge filled with medical adhesive also defines a side opening sized to accept a guidewire that facilitates navigation of the flexible catheter <NUM> to the target location within a patient. After positioning the flexible catheter <NUM> at the target location, the guidewire may be removed from the lumen of the catheter <NUM>. Then, the pre-filled cartridge may be advanced distally within the lumen of the flexible catheter <NUM> until the distal end of the pre-filled cartridge is distal to the side opening, such that the pre-filled cartridge covers the side opening and closes the side opening. In some examples, the flexible catheter <NUM> may include a flap configured to move between a first position that enables the guidewire to enter the side opening defined by the catheter <NUM> and a second position that closes the side opening from the lumen of the catheter <NUM>. Advancement of the pre-filled cartridge distally within the lumen of the flexible catheter <NUM> forces the flap from the first position to the second position. In some examples, the flap may be constructed of a more resilient material than the wall of the pre-filled cartridge. The wall of the pre-filled cartridge may bulge or burst at the side opening when subjected to the pressures applied by the shaft <NUM>. The flap may thus provide support for the wall of the pre-filled cartridge at the side opening and help ensure that medical adhesive is directed out of the distal opening of the flexible catheter <NUM>.

The lumen of the flexible catheter <NUM> may generally have a cross-sectional dimension in a range of approximately <NUM> inches (in) (<NUM> centimeters (cm)) to approximately <NUM> in (<NUM>). The external dimension (e.g., the external diameter) of the flexible catheter <NUM> may be in a range of approximately <NUM> in (<NUM>) to approximately <NUM> in (<NUM>). These sizes may correspond to flexible catheter <NUM> having a French sizing from a <NUM> French to a <NUM> French diameter.

However, smaller or larger diameters may be used in other examples. The flexible catheter <NUM> may be constructed of one or more polymer layers, and in some examples, the polymers may change along the length of the flexible catheter <NUM>. In some examples, the flexible catheter <NUM> may include a reinforced section comprising at least one of a coil or a braid within a wall of the flexible catheter <NUM> (e.g., embedded within the wall). The coil or braid may be constructed of a polymer or one or more metals. In some examples, the flexible catheter <NUM> may include a polytetrafluoroethylene (PTFE) liner that defines the lumen that contains the medical adhesive or is configured to accept a pre-filled cartridge that contains the medical adhesive.

In some examples, the medical adhesive described herein may have a viscosity between approximately <NUM>,<NUM> centipoise (cps) and <NUM>,<NUM> cps. In other examples, the medical adhesive may have a viscosity between <NUM>,<NUM> cps and <NUM>,<NUM> cps. The volume of medical adhesive pre-filled in the flexible catheter <NUM> or contained within a single pre-filled cartridge may be within a range from approximately <NUM> to approximately <NUM>. This volume may be selected based on target vessels to be treated (e.g., the greater saphenous vein may require a larger volume of medical adhesive than a perforator vein). Each bolus of medical adhesive delivered to a single location within the vessel may be in a range of approximately <NUM> cubic centimeters (cc) to <NUM> cc. In one example, each bolus may be in a range of approximately <NUM> cc to <NUM> cc of medical adhesive.

Example medical adhesives may include cyanoacrylate (e.g., <NUM>-octyl cyanoacrylate). In some examples, a cyanoacrylate can be an aliphatic <NUM>-cyanoacrylate ester such as an alkyl, cycloalkyl, alkenyl or alkoxyalkyl2-cyanoacrylate ester (e.g., VenaSeal™, Medtronic, Minneapolis, MN). The alkyl group may have from <NUM> to <NUM> carbon atoms in some embodiments, and can be a C1-C8 alkyl ester or a C1-C4 alkyl ester. Some possible esters include the methyl, ethyl, npropyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, <NUM>-methoxyethyl and <NUM>-ethoxyethyl esters of cyanoacrylic acid. Other medical adhesives that can be used include a biological glue such as a bovine serum albumin-gluteraldehyde combination (e.g., BIOGLUE, Cryolife, Atlanta, GA), PV A, Biogard, collagen, fibrinogen, fibronectin, vitronectin, laminin, thrombin, gelatin, mixtures thereof, or other biocompatible adhesives.

The flexible catheter <NUM> may deliver other fluids in other examples. Materials other than adhesives may be used, including a sclerosing agent such as hypertonic saline, sodium tetradecyl sulfate, chromated glycerol, tetracycline, talc, bleomycin, or polydocanol. For example, a foam generated from, for example, one or more of the above components can be used to enhance ablation and closure of the vein <NUM>. The viscosity and air bubble mixture can also be controlled while taking into account the desired clinical result. In some examples, the cyanoacrylate preparation contains one or more additives that impart the desired properties to the preparation as viscosity, color, radioopacity, and the like. Certain examples of additives such as thickening agents and polymerization inhibitors are discussed further below.

In some examples, the adhesive can also include a therapeutic agent such as an anti-inflammatory agent, an anti-infective agent, an anesthetic, a pro-inflammatory agent, a cell proliferative agent, or combinations thereof. In some examples, the medical adhesives, such as the cyanoacrylate adhesives, can have select properties. In some examples, the medical adhesives can have a setting time of between about <NUM> to <NUM> seconds, or less in some examples. The setting time may be almost instantaneous with blood contact in other examples.

<FIG> are conceptual views of an example procedure for delivering a vein-occluding substance, such as a medical adhesive, to a patient at multiple target locations. The procedure of <FIG> may be similar to <FIG>. However, <FIG> describe a procedure in which the medical adhesive adheres to an occlusion formed in a vein <NUM>, which is an example of the vein <NUM> described with reference to <FIG>. The flexible catheter <NUM> may be similar to the flexible catheter <NUM> of <FIG>.

As shown in the example of <FIG>, a flexible catheter <NUM> may be percutaneously introduced into the vein <NUM> at an access site and translumenally distally advanced across a treatment zone within the vein <NUM>. External compression, such as manual compression, is applied to collapse the vein <NUM> distally of the flexible catheter <NUM> and create a first occlusion <NUM> as shown in the example of <FIG>. After the creation of the occlusion <NUM> in the vein <NUM>, a first volume V1 within vein <NUM> can be defined between a distal end <NUM> of the flexible catheter <NUM> and the occlusion <NUM>, as illustrated in <FIG>. In other examples, external compression may not be needed when the adhesive may be an embolic that occludes blood flow within the vessel.

Medical adhesive having a second volume V2, such as in a bolus, can then be injected from the distal end <NUM> of the flexible catheter <NUM> into the vein <NUM> (e.g., by advancing a shaft <NUM> through the flexible catheter <NUM> to deliver medical adhesive from the distal end <NUM> of the flexible catheter <NUM>. In some examples, the second volume V2 (of the medical adhesive injected) is at least about <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or more of the first volume V1 (of the vein <NUM> in between the occlusion and the distal end <NUM> of the catheter <NUM>), such that a proximally advancing edge, or meniscus, of media V2 passes proximally past the distal end <NUM> of the flexible catheter <NUM>, as illustrated in <FIG>. The flexible catheter <NUM> is then withdrawn proximally, as illustrated in <FIG>, and a second more proximal occlusion <NUM> can be created, such as via external compression. Additional medical adhesive can then be injected to create a volume V2' greater than the volume within the vein <NUM> between the distal end <NUM> of the flexible catheter <NUM> and the occlusion <NUM>, as illustrated in FIG. This process can then be repeated for a total of at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more occlusions depending on the desired clinical result.

<FIG> is a conceptual view of an example system <NUM> configured to deliver a vein-occluding substance, such as a medical adhesive, to a patient. As shown in <FIG>, a system <NUM> includes a flexible catheter <NUM> and a mandrel <NUM>. The flexible catheter <NUM> may be similar to the flexible catheter <NUM> discussed above, and the mandrel <NUM> may be similar to the shaft <NUM> discussed above. The flexible catheter <NUM> may have an exterior wall <NUM> and an interior wall <NUM>. The interior wall <NUM> defines a lumen <NUM>, within which medical adhesive or a pre-filled cartridge containing the medical adhesive may be disposed. The flexible catheter <NUM> may also define a proximal opening <NUM> to the lumen <NUM>, into which a body <NUM> of the mandrel <NUM> may be inserted. Advancement of the body <NUM> through the lumen <NUM> may cause medical adhesive or other fluid within the lumen <NUM> to be dispensed out of a distal end <NUM> defined by the flexible catheter <NUM>, which corresponds to a distal opening of the lumen <NUM> in the example shown in <FIG>.

The mandrel <NUM> may include a body <NUM> attached to a handle <NUM>. The mandrel body <NUM> may be axially stiff and laterally flexible in order to be inserted through the lumen <NUM> of the flexible catheter <NUM> and providing a pushing force against adhesive or other medical fluid within the lumen <NUM>. A distal end <NUM> of the body <NUM> may have a distal surface (e.g., a flat surface) that is configured to apply a pressure to the medical adhesive within the lumen <NUM> of the flexible catheter <NUM>. In some examples, the distal surface of the distal end <NUM> may be rounded, domed, or have a slightly tapered tip that facilitates insertion of distal end <NUM> into the proximal opening <NUM> of the flexible catheter <NUM>.

In some examples, the mandrel body <NUM> includes markings <NUM> along the axial length of the mandrel body <NUM>. Markings <NUM> may indicate the amount of medical adhesive delivered from the flexible catheter <NUM> when comparing the position of the markings with respect to the proximal opening <NUM>. The mandrel body <NUM> may be constructed of a length that enables the distal end <NUM> to reach the distal opening <NUM> of the flexible catheter <NUM> while the handle <NUM> is proximal to the proximal opening <NUM>. In other examples, the mandrel body <NUM> may be constructed of a length that is less than the total length of the flexible catheter <NUM> in order to maintain a predetermined length of the flexible catheter <NUM> distal to the mandrel body <NUM> and flexible end that provides a more atraumatic tip than the distal end <NUM> of the mandrel body <NUM>.

The handle <NUM> may be sized for a human hand and promote manipulation of the mandrel body <NUM>. The handle <NUM> may be constructed of any suitable material, such as, but not limited to, a metal, metal alloy, polymer, or composite material. In some examples, a proximal end of the flexible catheter <NUM> may include a texturized outer surface or different material that facilitates a user's hand grabbing onto the proximal end of the flexible catheter <NUM>. In some examples, the proximal end of the flexible catheter <NUM> may have a larger diameter and/or stiffer material that can be manipulated by the user without collapsing the lumen <NUM>. In some examples, the distal end of the mandrel body <NUM> may be pre-inserted into the proximal opening <NUM> of the flexible catheter <NUM> to seal the medical adhesive from the external environment, e.g., during storage of the system <NUM>. In this manner, the manufacturer may deliver a system that includes the mandrel <NUM> and the flexible catheter <NUM> pre-filled with a predetermined volume of medical adhesive while maintaining the integrity of the prefilled medical adhesive. An example proximal end of a flexible catheter is shown in <FIG>.

In other examples, the mandrel body <NUM> may have a diameter that is the same or larger than the inner diameter of the flexible catheter <NUM>. However, in response to insertion of the mandrel body <NUM> into the lumen <NUM>, the flexible catheter <NUM> may expand, or stretch, radially to increase the inner diameter of the flexible catheter <NUM> to a size that accepts body <NUM>. In this manner, the stretching of the flexible catheter <NUM> may provide a tight seal around mandrel <NUM>. In addition, or alternatively, the mandrel body <NUM> may be covered by, or attached to, a compressible tip or non-compressible tip that has a larger diameter than the body <NUM>. In this manner, both the compressible tip and non-compressible tip may contact the inner wall <NUM> to prevent the adhesive from moving proximally, similar to a plunger of a syringe. The compressible tip may be reduced in diameter when inserted into the lumen <NUM>. The non-compressible tip may be sized just smaller than the lumen diameter in order to slide within the lumen <NUM> while also preventing most or all of the adhesive from moving proximally past the non-compressible tip.

<FIG> are perspective and cross-sectional views, respectively, of a proximal end of a flexible catheter <NUM> configured to deliver a vein-occluding substance to a patient. The flexible catheter <NUM> may be similar to the flexible catheters <NUM> and <NUM> discussed herein. As shown in <FIG>, the flexible catheter <NUM> includes an elongated member <NUM> that defines an external wall <NUM> and an internal wall <NUM>. The internal wall <NUM> defines a lumen <NUM>, which is configured to be prefilled with medical adhesive (or other medical fluid) or accept a pre-filled cartridge containing medical adhesive. A flange <NUM> is attached to the elongated member <NUM> and provides a surface a user may hold in order to manipulate the position of the flexible catheter <NUM>, e.g., in order to advance the flexible catheter <NUM> proximally or distally within vasculature of a patient.

As shown in the cross-sectional view of <FIG>, the flange <NUM> extends transverse to (e.g., perpendicular to) a longitudinal axis <NUM> of the elongated member <NUM>. The flange <NUM> may include concave surfaces facing distally to facilitate finger placement from the user when providing a proximal direction force to counteract a distal direction force created by advancing the mandrel <NUM> through the lumen <NUM>. In other examples, the proximal end of flexible catheter <NUM> may include a handle around the perimeter of the external wall <NUM> that enables a user to wrap fingers around the handle and then elongated member <NUM> when inserting the mandrel <NUM> into the lumen <NUM>, for example. In any case, the flexible catheter <NUM> may include a structure on its distal end that facilitates user handling of the flexible catheter <NUM> and the insertion and advancement of the mandrel <NUM> or other device such as the shaft <NUM> (<FIG>).

<FIG> is a cross-sectional view of the distal end of an example flexible catheter <NUM> pre-filled with a vein-occluding substance, such as a medical adhesive, and a shaft <NUM> within a lumen defined by the flexible catheter <NUM>. The flexible catheter <NUM> may be an example of the flexible catheters <NUM>, <NUM>, or <NUM> described herein. The flexible catheter <NUM> and the shaft <NUM> may provide a system that facilitates delivery of a medical adhesive into a patient for various treatments, such as the delivery of a medical adhesive to a vein for vessel occlusion. Prior to the medical procedure in which medical adhesive <NUM> is delivered to a patient, the medical adhesive <NUM> can be stored within the flexible catheter <NUM>. For example, a lumen of the flexible catheter <NUM> may be filled with medical adhesive <NUM> by the manufacturer and then stored and/or shipped for later use by a clinician. In this manner, the flexible catheter <NUM> may be both the storage and the delivery vessel of the medical adhesive <NUM>. Pre-filling the flexible catheter <NUM> with a volume of medical adhesive <NUM> may reduce the overall time for the procedure, reduce the amount of adhesive needed (i.e., the entire length of the catheter does not need to be primed with adhesive), and reduce the likelihood that the single-use flexible catheter <NUM> can be re-used for a medical procedure performed on another patient.

Pre-filling the flexible catheter <NUM> with medical adhesive <NUM> may be in contrast to alternative methods of distributing the medical adhesive which may include a separate vial of medical adhesive that the clinician or other user adds to the flexible catheter <NUM> prior to use in a procedure, such as by a syringe or other fluid delivery mechanism. In some examples, the flexible catheter <NUM> may have an increased volume and/or length to store the entire volume of medical adhesive <NUM> needed to perform a procedure as compared to other catheters that are not pre-filled with a medical adhesive. This may reduce clinician time when preparing for the procedure and reduce the likelihood of medical adhesive reuse for another patient. For example, a pre-filled flexible catheter <NUM> may eliminate the flexible catheter <NUM> from needing to be primed, or filled to displace air, by the clinician prior to the procedure. The example of <FIG> shows a distal end <NUM> of the flexible catheter <NUM>, where the distal end of the shaft <NUM> has already been inserted within a lumen of the flexible catheter <NUM>. The flexible catheter <NUM> may be constructed of any suitable material. For example, the flexible catheter <NUM> may include an outer wall <NUM> and an inner liner <NUM>. The outer wall <NUM> may define a cylinder shape and, in some examples, include a reinforced section that includes a reinforcing member <NUM>. The reinforcing member <NUM> may be a coil, braid, or other structure that provides structural reinforcement to the outer wall <NUM> that promotes pushability, trackability, and/or rink resistance of the flexible catheter <NUM>. The outer wall <NUM> may be constructed of one or more polymers (e.g., polytetrafluoroethylene (PTFE) or a thermoplastic such as Pebax®). Since the flexible catheter <NUM> is prefilled with medical adhesive <NUM>, the flexible catheter <NUM> may not benefit from being translucent as would otherwise be beneficial during priming of the catheter <NUM> with medical adhesive. The ability of the flexible catheter <NUM> to be opaque may enable a broader range of catheter designs, such as a catheter <NUM> that includes a reinforcing member <NUM>. In addition, in some examples, the outer wall <NUM> may be filled with an echogenic material, such as ZnO2, TiO2, or the like. (e.g. as described in <CIT> assigned to Medtronic, Inc. ) Such an opaque the outer wall <NUM> may be constructed thinner than those materials that remain translucent. A thinner outer wall <NUM> may reduce the outer diameter of the flexible catheter <NUM> which may increase patient comfort and facilitate insertion of the flexible catheter <NUM>. In some examples, the flexible catheter <NUM> may be constructed with various stiffness profiles. In one example, the proximal end of the flexible catheter <NUM> may be stiffer than the distal end of the flexible catheter <NUM>. In another example, the distal end of the flexible catheter <NUM> may be stiffer than the proximal end of the flexible catheter <NUM>.

The reinforcing member <NUM> may be within the outer wall <NUM> (e.g., embedded within the outer wall <NUM> or sandwiched between two layers of outer wall <NUM>, and the reinforcing member <NUM> may be constructed of a metal, metal alloy, polymer, or composite maters. The reinforcing member <NUM> may be constructed of a material that is more rigid than the outer wall <NUM>. The inner liner <NUM> may define the lumen of the flexible catheter <NUM> for holding medical adhesive <NUM>. The inner liner <NUM> may be formed or otherwise constructed by a material that is resistant to adhering to medical adhesive <NUM>. For example, the liner <NUM> may be constructed of PTFE that prevents medical adhesive <NUM> from adhering to the inner surface of the flexible catheter <NUM>. In addition to, or in an alternative to, the liner <NUM>, the surfaces of the flexible catheter <NUM> defining the inner lumen in which an adhesive is contained may include a hydrophilic or hydrophobic material selected to resist interaction with the formulation of medical adhesive <NUM>. In some examples, the outer surface of the outer wall <NUM> may coated with a hydrophilic, hydrophobic, and/or lubricous material to aid in insertion within the vessel of the patient.

The flexible catheter <NUM> may also include an echogenic portion at the distal portion of the flexible catheter <NUM>, where the echogenic portion promotes visualization under ultrasound imaging. By limiting the echogenic portion to the distal portion of the flexible catheter <NUM>, the rest of the proximal portion of the flexible catheter <NUM>, such as the outer wall <NUM> and the liner <NUM>, may be thinner to promote a greater volume capacity to hold medical adhesive <NUM> while enabling a larger inner diameter (lumen) for a given outer diameter of the flexible catheter <NUM>. In this manner, the inner diameter of the flexible catheter <NUM> may be smaller at the distal end than at more proximal locations in order to accommodate these echogenic materials.

In some examples, echogenic properties of the flexible catheter <NUM> may be provided by the air channels 92A and 92B disposed at the distal end of the flexible catheter <NUM> and within wall material <NUM> (which may be similar to the outer wall <NUM>). The liner <NUM> may extend to the distal end <NUM> of the flexible catheter <NUM> and until the distal opening <NUM>. In some examples, the distal opening <NUM> may be covered with a flap or breakable cover that is forced open from increased pressure from the shaft <NUM> against the adhesive <NUM>. In other examples, cap may cover the flexible catheter <NUM> that is pre-filled with the adhesive <NUM>, and the clinician or other user may remove the cap just prior to insertion of the flexible catheter <NUM> into the patient. Instead of, or in addition to, the air channels 92A and 92B, the flexible catheter <NUM> may include other echogenic materials near the distal opening <NUM>. In some examples, a radiopaque marker, such as a metal band <NUM>, positioned at or near the distal end <NUM> of the flexible catheter <NUM> to promote visualization under ultrasound, x-ray, fluoroscopy, or other imaging modality. In some examples, the metal band <NUM> may be coated by a polymer, such as PTFE, the metal band <NUM> may be disposed on the radially outward surface of the flexible catheter <NUM>, and/or the metal band <NUM> may be swaged to the distal end of the flexible catheter <NUM>.

The cross-sectional dimension of the shaft <NUM> (e.g., the diameter or cross-sectional area) is sized to correspond with the cross-sectional dimension of the lumen defined by the liner <NUM>. Therefore, the shaft <NUM> may have a dimension slightly smaller than that of the liner <NUM> to enable the shaft <NUM> to be advanced through the lumen defined by the liner <NUM> while preventing or reducing any medical adhesive <NUM> from passing back between the shaft <NUM> and the liner <NUM>. The shaft <NUM> may be manually advanced by the user from the proximal end of the flexible catheter <NUM> (not shown in <FIG>). In some examples, the shaft <NUM> may be delivered out of a coiled carrier tube proximal to the proximal opening of the flexible catheter <NUM>. Since the shaft <NUM> may be coiled until inserted into the lumen of the flexible catheter <NUM>, a long length of the shaft <NUM> extending back from the flexible catheter <NUM> may not complicate maneuvering the flexible catheter <NUM> or otherwise require additional space near the patient. The shaft <NUM> may be an example of body <NUM> of the mandrel <NUM> described with respect to <FIG>.

Delivering medical adhesive <NUM> that was pre-filled within the lumen (filled by medical adhesive <NUM> and shaft <NUM> in the example of <FIG>) of the flexible catheter <NUM> may provide advantages over systems in which the medical adhesive is delivered from an injector or syringe that is attached to a proximal end of a catheter. For example, the pre-filled flexible catheter <NUM> may reduce setup time prior to delivering medical adhesive <NUM> into a patient, such as time required to prime a syringe and catheter with medical adhesive stored in a vial. In addition, delivery of the medical adhesive <NUM> from the flexible catheter <NUM> via force provided from the shaft <NUM> may reduce the force required to deliver medical adhesive <NUM> out of the distal opening <NUM>.

As an example, a <NUM> cubic centimeter (cc) syringe filled with medical adhesive may have a diameter of <NUM> in (<NUM>). However, the diameter of the lumen within the flexible catheter <NUM> may be significantly smaller, which reduces the force needed to displace medical adhesive <NUM> from the flexible catheter <NUM>. This reduction in force may improve deliverability by the user.

Examples of pressure reduction for various different dimensions of the flexible catheter <NUM> as compared to a <NUM> cc syringe with a diameter of <NUM> in (<NUM>) are described below in Table <NUM>.

As shown in Table <NUM>, "Vol" is the volume of the flexible catheter <NUM>, "ID" is the inner diameter of the catheter <NUM> that defines the lumen, "OD" is the outside diameter of the catheter <NUM>, "Wall" is the wall thickness from the lumen to the outer surface of the catheter <NUM>, "Length" is the overall length of the flexible catheter <NUM> from its proximal end to its distal end, and "Pressure Reduction" is the estimated pressure reduction as compared to a system that delivers medical adhesive using a <NUM> cc syringe attached to a catheter with dimensions of the catheter of example A.

Table <NUM> indicates that reductions to the inner diameter, and, thus, the cross-sectional area, of the lumen of the flexible catheter <NUM> generally reduces the pressure as compared to the syringe. In order to increase the volume of the flexible catheter <NUM> while also maintaining reduced delivery pressures, a longer length of the flexible catheter <NUM> may be used. These dimensions of the flexible catheter <NUM> may be adjusted for certain use cases. For example, the length of the flexible catheter <NUM>, inner diameter, and/or outer diameter may be reduced to hold less volume of medical adhesive <NUM> when a smaller vessel (e.g., perforator vein or spider vein) is to be treated. In these examples, smaller shafts may be used to correspond with smaller inner diameter flexible catheters such as the flexible catheter <NUM>.

In addition to decreasing required pressures for delivery as compared to using a syringe, delivering medical adhesive <NUM> by advancing a shaft <NUM> through a catheter lumen may reduce compliance in the adhesive delivery system and enable a more controlled delivery of medical adhesive <NUM>. This reduced compliance may also reduce the amount of "dribble" of medical adhesive that continues to flow from distal opening <NUM> after the user stops applying pressure to shaft <NUM>. However, the flexible catheter <NUM> may be constructed to provide a desired amount of dribble that the clinician may be expecting to finish delivery of a bolus of the medical adhesive <NUM>.

In some examples, the shaft <NUM> and/or a handle portion attached to a proximal portion of shaft <NUM> may include indents or detents that interface with the flexible catheter <NUM> to provide tactile feedback to the user on the delivery amount of medical adhesive from distal opening <NUM>. In addition, or alternatively, the shaft <NUM> can include visual markers on a proximal portion that becomes covered by the flexible catheter <NUM> as the shaft <NUM> is advanced distally into the catheter lumen to indicate how much volume of medical adhesive <NUM> was delivered out of distal opening <NUM> as the distance shaft <NUM> was advanced distally with respect to the flexible catheter <NUM>. For example, the visual markers of the shaft <NUM> may be substantially similar to the markers <NUM> of the body <NUM> of the mandrel <NUM> of illustrated in <FIG>.

<FIG> are cross-sectional views of different axial positions A and B, respectively, along the catheter of <FIG>. As shown in <FIG>, the liner <NUM> of the catheter <NUM> is radially inward of the outer wall <NUM>. The liner <NUM> may define the catheter lumen configured to receive the shaft <NUM>. As shown in <FIG>, the distal end of the flexible catheter <NUM> includes metal band <NUM> defining an outside surface around a wall <NUM>. The wall <NUM> may be constructed of the same or similar material as the outer wall <NUM>. The liner <NUM> is disposed radially within the wall <NUM> and defines the lumen within which the medical adhesive <NUM> is disposed. The wall <NUM> also defines two air channels 92A and 92B, which provide the catheter <NUM> with echogenic features. In other examples, a single air channel or three or more air channels may be defined by wall <NUM>.

As shown in <FIG>, the diameter of the catheter lumen within axial position B is smaller than axial position A of the flexible catheter <NUM>. This smaller lumen diameter may result from the addition of echogenic materials (e.g., air channels 92A and 92B) and/or the metal band <NUM> as compared to proximal portions of the flexible catheter <NUM>. The smaller diameter at the axial position B may also be smaller than the diameter of the shaft <NUM> to help keep the shaft <NUM> within catheter <NUM> during a medical procedure and prevent the shaft <NUM> from exiting the distal opening <NUM> and adversely impacting tissue of the patient.

<FIG> is a cross-sectional view of the distal end of an example flexible catheter <NUM> pre-filled with medical adhesive <NUM> and defining a guidewire the exit port <NUM>. <FIG> also illustrates a shaft <NUM> inside an inner lumen <NUM> of the catheter <NUM>. As shown in the example of <FIG>, the flexible catheter <NUM> includes the outer wall <NUM>, a reinforcing member <NUM>, and an inner liner <NUM>. The flexible catheter <NUM> and the shaft <NUM> may be substantially similar to the flexible catheter <NUM> and the shaft <NUM>, respectively, of <FIG>. For example, the outer wall <NUM> of the catheter <NUM> may be similar to the outer wall <NUM>, the reinforcing member <NUM> may be similar to the reinforcing member <NUM>, the inner liner <NUM> may be similar to the inner liner <NUM>, and the shaft <NUM> may be similar to the shaft <NUM>. However, the flexible catheter <NUM> defines a guidewire exit port <NUM> configured to receive a guidewire <NUM> that may be used to facilitate navigation of the flexible catheter <NUM> to a target site within a vessel (or other hollow anatomical structure) of the patient. The shaft <NUM> is configured to be disposed within the lumen <NUM> defined by the liner <NUM> and proximal to the medical adhesive <NUM> contained within the lumen <NUM>.

The outer wall <NUM> defines an exit port <NUM>, which is an opening from the lumen <NUM> to the outside of the flexible catheter <NUM>. One end of a flap <NUM> is attached to the outer wall <NUM> and the remainder of the flap <NUM> is dimensioned to extend across the lumen <NUM> to block flow through the lumen <NUM> past the flap <NUM>. For example, the remainder of the flap <NUM> may be sized and configured to match the cross-sectional area of lumen <NUM> and seal medical adhesive <NUM> proximal to the flap <NUM> and the exit port <NUM>. In this manner, the flexible catheter <NUM> can be prefilled with medical adhesive <NUM> while also enabling the use of the guidewire <NUM>. The guidewire <NUM> may be navigated to a target treatment site within the vessel, and then the flexible catheter <NUM> may be navigated to the target treatment site inserted over the guidewire <NUM>. In this manner, the guidewire <NUM> may extend through the exit port <NUM> and out of the distal opening <NUM>. The flexible catheter <NUM> may thus be referred to as a rapid exchange catheter in some examples.

The flap <NUM> may be constructed as one or more layers of material (e.g., a polymer such as polyurethane, a metal or metal alloy, or composite material) that form a movable membrane. In some examples, the flap <NUM> may be constructed of collagen or some other biological based material configured to occlude the exit port <NUM>, and when the flap <NUM> is "opened" to open the lumen <NUM> and enable flow of fluid through the lumen <NUM> and distal to the exit port <NUM>. The flap <NUM> may be configured to stay in place to hold medical adhesive <NUM> proximal to the exit port <NUM> until a sufficient force is applied to the flap <NUM> from the medical adhesive <NUM>. When the guidewire <NUM> is removed from the flexible catheter <NUM>, advancement of the shaft <NUM> may increase the pressure applied to medical adhesive <NUM> until the pressure forces the distal movement of medical adhesive <NUM> to cause the flap <NUM> to move distally to cover the exit port <NUM> (as shown in <FIG>).

Once the flap <NUM> covers the exit port <NUM>, medical adhesive <NUM> may flow towards the distal opening <NUM> without medical adhesive exiting through the exit port <NUM>. In some examples, the flap <NUM> may be glued to an inner surface of the outer wall <NUM> and/or the liner <NUM>. For example, a proximal portion <NUM> of the flap <NUM> may be adhered to the inner or exterior surface of the outer wall <NUM>. In other examples, the proximal portion <NUM> of the flap <NUM> may be formed from or otherwise attached to the outer wall <NUM> and/or the liner <NUM>. A distal portion <NUM> of the flap <NUM> may also be adhered to the liner <NUM>, friction fit in place, or otherwise set against liner <NUM> to seal medical adhesive <NUM> within the lumen <NUM> proximal to the flap <NUM>. However, in some examples, the distal portion <NUM> may refer to the outer edges of the flap <NUM> when the flap <NUM> is circular in shape. In any case, the distal portion <NUM> may be less strongly adhered or attached to the flexible catheter <NUM> such that the pressure from medical adhesive <NUM> causes the distal portion <NUM> to release while the proximal portion <NUM> remains attached to prevent the flap <NUM> from being detached. In other examples, the flap <NUM> may define a perforated, thinned, or pre-slit portion that breaks in response to higher pressures from medical adhesive <NUM>. The remnants of the flap <NUM> may still be sized to fold over against the inner wall of the liner <NUM> and cover the exit port <NUM>.

The exit port <NUM> may be a side opening defined by the outer wall <NUM> and the liner <NUM>. The exit port <NUM> may be disposed distal to the medical adhesive <NUM> pre-filled within the lumen <NUM> of the flexible catheter <NUM>. The exit port <NUM> may be sized to accept one or more different dimensioned guidewires <NUM>. The exit port <NUM> may be defined by surfaces perpendicular with the longitudinal axis of the flexible catheter <NUM> such that a longitudinal axis defined by the exit port <NUM> is perpendicular to the longitudinal axis of the flexible catheter <NUM>. In other examples, the exit port <NUM> may be defined by an oblique surface within the outer wall <NUM> and/or the liner <NUM> such that the longitudinal axis of the exit port <NUM> is not parallel or perpendicular to the longitudinal axis of the flexible catheter <NUM>. The oblique surface may help guide the guidewire <NUM> into the lumen <NUM> distal to the adhesive <NUM>.

<FIG> are cross-sectional views of different axial positions C and D, respectively, along the flexible catheter <NUM> of <FIG>. As shown in <FIG>, the flexible catheter <NUM> includes the inner liner <NUM> radially inward of the outer wall <NUM>. The liner <NUM> may define the lumen <NUM>, within which the shaft <NUM> is disposed. As shown in <FIG>, the distal end of the flexible catheter <NUM> includes the outer wall <NUM> radially outward of the liner <NUM>. The liner <NUM> defines lumen <NUM>, and the guidewire <NUM> is disposed within lumen <NUM>.

<FIG> are cross-sectional views parallel with the longitudinal axis of the flexible catheter <NUM> from <FIG> in which the guidewire <NUM> is removed from the exit port <NUM>. In the example of <FIG>, the flap <NUM> is in a first position that blocks the lumen <NUM> and retains the volume of medical adhesive <NUM> proximal to the flap <NUM> and the exit port <NUM>. However, as shown in <FIG>, the flap <NUM> is configured to move from the first position to a second position, in which the flap <NUM> closes the exit port <NUM> (e.g., a side opening in the flexible catheter <NUM>) from lumen <NUM>.

Once the flexible catheter <NUM> is positioned at the target location within the patient, a clinician may proximally withdraw the guidewire <NUM> from the lumen <NUM> via the exit port <NUM>. At this point, the flap <NUM> may remain in the first position to hold medical adhesive <NUM> proximal to the exit port <NUM>. When the clinician desires to deliver medical adhesive <NUM> from the distal opening in the flexible catheter <NUM>, the clinician may advance the shaft <NUM> in the distal direction (as indicated by arrow <NUM>), which increases the pressure of the medical adhesive <NUM> and advances medical adhesive <NUM> distally within the lumen <NUM> to force the flap <NUM> from the first position to the second position. The proximal portion <NUM> of the flap <NUM> may act like a hinge to enable the rest of the flap <NUM> to move within lumen <NUM>.

The second position of the flap <NUM> is shown in <FIG>, where the distal portion <NUM> of the flap <NUM> contacts a portion of the liner <NUM> and/or the outer wall <NUM> distal to the exit port <NUM> in order to close off the lumen <NUM> from the exit port <NUM>. In the second position, the flap <NUM> enables the medical adhesive <NUM> to flow along a radially inward facing surface of the flap <NUM> and into the distal portion of the lumen <NUM> until at least a portion of medical adhesive <NUM> exits the flexible catheter <NUM> through the distal opening.

In some examples, some or all of the flap <NUM> may be configured to contact the inward facing portions of the outer wall <NUM> at a region in which liner <NUM> is not disposed. In this manner, the flap <NUM> may be substantially flush with the liner <NUM> when in the second position as shown in <FIG>. In other examples, the flap <NUM> may be attached to and/or in contact with liner <NUM> in the second position. Since the flap <NUM> may be relatively thin, the resulting reduction in lumen diameter may not significantly affect the advancement of medical adhesive <NUM> or the shaft <NUM> within the catheter lumen <NUM>. However, the flap <NUM> may be constructed of a material that has a stiffness and/or thickness that resists the pressure from medical adhesive <NUM> generated by the advancement of shaft <NUM> to prevent medical adhesive <NUM> from passing out of the exit port <NUM>.

As shown in <FIG>, the flap <NUM> in the second position may enable the distal end of the shaft <NUM> to pass distally of the flap <NUM> and the exit port <NUM>. For example, the distal portion <NUM> of the flap <NUM> may rest against the liner <NUM> and/or the outer wall <NUM> and not inhibit the advancement of the shaft <NUM>. Therefore, the flap <NUM> may not interfere with the shaft <NUM> to moving distal to the exit port <NUM> to continue dispensing medical adhesive <NUM> from the distal opening of the catheter <NUM> until the procedure is complete or all of medical adhesive <NUM> has been delivered from the flexible catheter <NUM>.

<FIG> is a cross-sectional view of the distal end of an example flexible catheter <NUM> configured to accept a pre-filled cartridge <NUM> filled with a vein-occluding substance such as a medical adhesive <NUM>. The flexible catheter <NUM> may be an example of flexible catheters <NUM>, <NUM>, or <NUM> described herein that facilitates delivery of medical adhesive <NUM> for various treatments, such as the delivery of medical adhesive <NUM> to a vein for vessel occlusion. In addition, the flexible catheter <NUM> may be similar to the flexible catheter <NUM> and be configured to receive a shaft (such as the shaft <NUM> shown in <FIG>) that is similar to the shaft <NUM>. For example, the outer wall <NUM> may be similar to the outer wall <NUM>, the reinforcing member <NUM> may be similar to the reinforcing member <NUM>, the inner liner <NUM> may be similar to the inner liner <NUM>, the outer wall <NUM> may be similar to the outer wall <NUM>, the metal band <NUM> may be similar to the metal band <NUM>, and the air lumens 142A and 142B may be similar to the air lumens 92A and 92B. However, the flexible catheter <NUM> may be configured to receive the pre-filled cartridge <NUM> which is a structure separate from the catheter <NUM> and contains a predetermined volume of medical adhesive <NUM>.

The pre-filled cartridge <NUM> may be a sealed tube or other container defined by at least a side wall 148C, a proximal wall 148A, and a distal wall 148B. The outer diameter (or other cross-sectional dimension) of the pre-filled cartridge <NUM> may correspond to the cross-sectional dimension of lumen <NUM> of the catheter <NUM>. In this manner, the outer diameter of the pre-filled cartridge <NUM> may be smaller than the diameter of the lumen <NUM> to facilitate insertion of the pre-filled cartridge <NUM> into the lumen <NUM>. The pre-filled cartridge <NUM> may be filled with a predetermined volume of medical adhesive <NUM> by a manufacturer, and the pre-filled cartridge <NUM> may be stored and delivered to a user for insertion into the flexible catheter <NUM> prior to performing the procedure on the patient. In this manner, the user may insert the pre-filled cartridge <NUM> into lumen <NUM> defined by the liner <NUM> when the flexible catheter <NUM> is completely outside of the patient or after the flexible catheter <NUM> is positioned within the target vessel.

The proximal wall 148A and the distal wall 148B of the pre-filled cartridge <NUM> may be configured to rupture in response to pressure applied to the walls 148A, 148B either directly or indirectly by a shaft (e.g., the shaft <NUM> of <FIG>). Therefore, advancement of the shaft <NUM> may cause medical adhesive <NUM> to flow out of distal opening <NUM> defined by the distal tube <NUM> of the pre-filled cartridge <NUM>. Although the distal tube <NUM> is shown as protruding distally of the distal end of the flexible catheter <NUM>, the distal tube <NUM> may terminate at the same position or proximally from the distal end of the flexible catheter <NUM> in other examples.

In other examples, the flexible catheter <NUM> may be pre-loaded with the pre-filled cartridge <NUM> by the manufacturer. However, a benefit of the pre-filled cartridge <NUM> may be that additional pre-filled cartridges may be inserted into the flexible catheter <NUM> if additional medical adhesive <NUM> is required during the procedure. A spent (e.g., empty or otherwise used) pre-filled cartridge <NUM> may be removed from the lumen <NUM> of the flexible catheter <NUM> by withdrawing the shaft <NUM> used to push medical adhesive <NUM> out of the distal opening <NUM>. For example, the pre-filled cartridge <NUM> may be friction fit to the shaft <NUM> or otherwise in contact with the shaft <NUM> sufficient to be withdrawn proximally out of the proximal end of the flexible catheter <NUM> in response to proximal withdrawal of the shaft <NUM> from the catheter lumen <NUM>. Alternatively, the spent pre-filled cartridge <NUM> may remain within the catheter lumen <NUM> and the subsequent pre-filled cartridge may "stack" proximally from the cartridge <NUM> such that the additional medical adhesive flows through the spent cartridge <NUM> as it is expelled from another pre-filled cartridge and prior to being delivered to the patient. In yet another example, the outer wall <NUM> at the distal end of the flexible catheter <NUM> may be removably attached, such as by threading the outer wall <NUM> to the distal end of the flexible catheter <NUM>. In such an example, the outer wall <NUM> may be removed from the flexible catheter <NUM>, the spent cartridge <NUM> removed, a new pre-filled cartridge <NUM> inserted, and the outer wall <NUM> re-attached.

The pre-filled cartridge <NUM>, such as the proximal wall 148A, the distal wall 148B, and the side wall 148C, may be formed from any suitable material, such as, but not limited to, a polymer such as polypropylene, high density polyethylene (HDPE), or PTFE. Materials such as these may exhibit a low coefficient of friction and enable insertion of the pre-filled cartridge <NUM> through the lumen <NUM> of the flexible catheter <NUM>. In some examples, the pre-filled cartridge <NUM> may include an echogenic region such that the position of the pre-filled cartridge <NUM> may be visible under ultrasound imaging.

The proximal wall 148A of the pre-filled cartridge <NUM> may be configured to be removed, punctured, or ruptured by the shaft <NUM>. In some examples, the distal end of the shaft <NUM> may be tapered to facilitate puncturing of proximal wall 148A. In some examples, the proximal wall 148A may be configured as a cap that can be removed or punctured prior to or during use. The distal wall 148B of the pre-filled cartridge <NUM> may also be configured to be removed, punctured, or ruptured by the increased pressure generated in medical adhesive <NUM> by the distal advancement of the shaft <NUM> within the catheter lumen <NUM>. In other examples, the distal wall 148B may be a cap or cover that is configured to be removed or punctured prior to the user inserting the pre-filled cartridge <NUM> within the catheter lumen <NUM>.

In some examples, the outer wall <NUM> at the distal end of the flexible catheter <NUM> may have a greater thickness than the outer wall <NUM>, which results the inner lumen <NUM> having a smaller diameter at the distal portion of the catheter. For example, the outer wall <NUM> may define a shoulder <NUM>. This shoulder <NUM> may prevent the pre-filled cartridge <NUM> from being advanced out the distal end of the flexible catheter <NUM>. Put another way, the shoulder <NUM> may enable the advancement of the shaft <NUM> to increase the pressure within the pre-filled cartridge <NUM> such that medical adhesive <NUM> can be dispensed out from distal opening <NUM> without the prefilled cartridge <NUM> itself being pushed out the distal end of the catheter <NUM>.

Providing medical adhesive <NUM> by way of one or more pre-filled cartridges <NUM> may provide one or more advantages over syringe-based delivery of medical adhesive. For example, the use of pre-filled cartridges may reduce the risk of adhesive and/or device reuse in another patient. Since the pre-filled cartridge <NUM> has already been within a patient, a clinician may not attempt to deliver any remaining medical adhesive <NUM> within a different patient. In addition, even if some medical adhesive <NUM> remains after treating one patient, this relatively small amount of medical adhesive <NUM> may have little value for use on another patient. Delivery of medical adhesive <NUM> via pre-filled cartridges such as the pre-filled cartridge <NUM> may also facilitate adding more medical adhesive for a procedure when needed and reduce possible waste of medical adhesive from a patient that only requires a small volume of medical adhesive. In some examples, pre-filled cartridges may be constructed with different volumes of medical adhesive <NUM> for certain types of vessels or procedures so that the clinician can use a pre-filled cartridge with the appropriate volume of medical adhesive. For example, the length of the pre-filled cartridge <NUM> and/or diameter of the pre-filled cartridge <NUM> may be specified to hold a certain volume of medical adhesive <NUM>.

<FIG> are cross-sectional views of different axial positions B and C, respectively, along the flexible catheter <NUM> of <FIG>. As shown in <FIG>, the inner liner <NUM> of the catheter <NUM> is radially inward of the outer wall <NUM>. The liner <NUM> may define the lumen <NUM>, within which the side wall 148C of the pre-filled cartridge <NUM> is disposed. In addition, the pre-filled cartridge <NUM> contains medical adhesive <NUM>. As shown in <FIG>, the distal end of the flexible catheter <NUM> includes a metal band <NUM> defining an outside surface around the wall <NUM>. The wall <NUM> may be constructed of the same or similar material as the outer wall <NUM>. The wall <NUM> also defines two air channels 142A and 142B, which are echogenic features that configure the distal portion of the catheter <NUM> to be seen by ultrasound imaging. In other examples, a single air channel or three or more air channels may be defined by wall <NUM>. The liner <NUM> is disposed radially within the wall <NUM> to define the lumen <NUM> within which distal tube <NUM> of the pre-filled cartridge <NUM> is disposed. Medical adhesive <NUM> may be dispensed through the distal opening <NUM> defined by the distal tube <NUM> of the pre-filled cartridge <NUM>.

<FIG> are cross-sectional views of example the flexible catheter <NUM> from <FIG> and illustrates a state in which the shaft <NUM> of a mandrel has been advanced distally through the catheter lumen <NUM> to force medical adhesive <NUM> out of the pre-filled cartridge <NUM>. As shown in <FIG>, the cross-sectional dimension of the shaft <NUM> is sized to correspond with, and be disposed within, a cross-sectional dimension of the lumen <NUM> defined by the inner surface of the cartridge side wall 148C. Therefore, advancement of the distal end of the shaft <NUM> through a proximal portion of the pre-filled cartridge <NUM> forces at least a portion of medical adhesive <NUM> out of a distal end of the pre-filled cartridge <NUM> and out of the distal opening <NUM> of the pre-filled cartridge <NUM> and the distal opening of the flexible catheter <NUM>.

As shown in <FIG>, advancement of the shaft <NUM> in the direction of arrow <NUM> causes the cartridge proximal wall 148A to break free of its position and be moved with the distal end of the shaft <NUM> through the lumen of the pre-filled cartridge <NUM>. In other examples, the cartridge proximal wall 148A may be punctured or ruptured such that the proximal wall 148A remains attached to the side wall 148C, but the shaft <NUM> can pass through the proximal wall 148A and contact the proximal edge of the volume of medical adhesive <NUM> stored within the pre-filled cartridge <NUM>. The increased pressures within medical adhesive <NUM> caused by advancement of the shaft <NUM> may cause the cartridge distal wall 148B to rupture and allow medical adhesive to flow out of the pre-filled cartridge <NUM>, e.g., past the distal wall 148B, through the distal tube <NUM>, and out of the distal opening <NUM>. In other examples, the cartridge distal wall 148B may be removed by the user prior to inserting the pre-filled cartridge <NUM> within the flexible catheter <NUM>.

In other examples, the shaft <NUM> may be constructed with a diameter that is larger than the diameter of the lumen of the pre-filled cartridge <NUM> and smaller than the diameter defined by the catheter inner liner <NUM>. Therefore, advancement of the shaft <NUM> may collapse the cartridge side wall 148C as medical adhesive <NUM> is advanced out of the distal opening <NUM>. Additional pre-filled cartridges may still be inserted within the flexible catheter <NUM> if needed, as pressure from the shaft <NUM> may still cause the additional medical adhesive from the subsequent pre-filled cartridge(s) to flow past the first the pre-filled cartridge <NUM> and out of distal opening <NUM>. The collapsed spent cartridge(s) may then remain within the flexible catheter <NUM> and discarded once the procedure is completed for the patient.

In some examples, a catheter that configured to receive a pre-filled cartridge of a medical adhesive may be a rapid-exchange type catheter. <FIG> are cross-sectional views of an example of such a catheter <NUM> and an example guidewire <NUM> configured to be inserted through a guidewire exit port <NUM> defined by the catheter <NUM>. As shown in the example of <FIG>, the flexible catheter <NUM> includes an outer wall <NUM>, a reinforcing member <NUM>, and an inner liner <NUM>. The flexible catheter <NUM> may be substantially similar to the flexible catheter <NUM> of <FIG>. For example, the outer wall <NUM> may be similar to the outer wall <NUM>, the reinforcing member <NUM> may be similar to reinforcing member <NUM>, and the liner <NUM> may be similar to liner <NUM>. The pre-filled cartridge <NUM> is similar to the pre-filled cartridge <NUM> and contains a volume of medical adhesive <NUM> that is similar to the medical adhesive <NUM>. However, the flexible catheter <NUM> may define the guidewire exit port <NUM> to facilitate navigation of the flexible catheter <NUM> through vasculature of a patient to a desired location within a vessel of the patient.

The outer wall <NUM> defines the exit port <NUM>, which is an opening from the catheter lumen <NUM> to the outside of the flexible catheter <NUM>. The exit port <NUM> may be a side opening defined by at the outer wall <NUM> and the inner liner <NUM>. The exit port <NUM> may be sized to accept one or more different dimensioned guidewires <NUM>. The exit port <NUM> may be defined by surfaces perpendicular with the longitudinal axis of flexible catheter <NUM> such that a longitudinal axis defined by the exit port <NUM> is perpendicular to the longitudinal axis of the flexible catheter <NUM>. In other examples, the exit port <NUM> may be defined by oblique surface within the outer wall <NUM> and/or the liner <NUM> such that the longitudinal axis of the exit port <NUM> is not parallel or perpendicular to the longitudinal axis of the flexible catheter <NUM>.

The guidewire <NUM> may be navigated to a target location within the vasculature of the patient, and then the flexible catheter <NUM> may be navigated to the target location over the guidewire <NUM>. In this manner, the guidewire <NUM> may extend through the exit port <NUM> and out of the distal opening <NUM>. The flexible catheter <NUM> may thus be referred to as a rapid exchange catheter in some examples.

In the example of <FIG>, the pre-filled cartridge <NUM> has not yet been inserted within the catheter lumen <NUM> or has been inserted but remains proximal to the exit port <NUM>. When the guidewire <NUM> is removed from the flexible catheter <NUM>, as shown in <FIG>, distal advancement of the pre-filled cartridge <NUM> in the direction of the arrow <NUM> may position the pre-filled cartridge <NUM> adjacent to the exit port <NUM>. In this manner, a portion of the pre-filled cartridge <NUM> covers and closes the exit port <NUM> to prevent medical adhesive <NUM> from being expelled through the exit port <NUM> in response to advancement of the shaft <NUM> against the pre-filled cartridge <NUM>.

In some examples, the flexible catheter <NUM> may include a flap similar to the flap <NUM> of the flexible catheter <NUM> in <FIG>. The flap may be configured to move between a first position that enables the guidewire <NUM> to enter the exit port <NUM> and a second position that closes the exit port <NUM> from the lumen <NUM>. Distal advancement of the pre-filled cartridge <NUM> in the direction of the arrow <NUM> within the catheter lumen <NUM> may force the flap from the first position to the second position that closes the exit port <NUM> to help prevent medical adhesive <NUM> from being expelled out the exit port <NUM>. The pre-filled cartridge <NUM> may then slide past the flap and hold the flap in the second position against the exit port <NUM>.

<FIG> is a flow diagram of an example technique for delivering a volume of vein-occluding substance, such as a medical adhesive, out of a catheter pre-filled with the vein-occluding substance by advancing a shaft within the catheter. For illustrative purposes, the techniques of <FIG> are described with reference to the various aspects of the flexible catheter <NUM> and shaft <NUM> of <FIG>. However, such descriptions are not intended to be limiting and the techniques of <FIG> may be used with other devices or systems, such as flexible catheters <NUM>, <NUM>, <NUM>, <NUM>, shafts <NUM> or <NUM>, and/or the mandrel <NUM>.

As shown in the example of <FIG>, a user may insert or deliver a distal end of the flexible catheter <NUM> to a target location within a hollow anatomical structure of a patient, such as a vein (<NUM>). In some examples, a user may use an ultrasound transducer to visualize the target location and the distal end of the flexible catheter <NUM>. The flexible catheter <NUM> may be pre-filled with medical adhesive <NUM> to be delivered to the patient. In some examples, the user may insert the flexible catheter <NUM> without the aid of other devices. For example, the catheter <NUM> may include the reinforcing member <NUM> or other structural features that increase the structural integrity and pushability of the catheter <NUM> to enable the catheter <NUM> to be navigated through the vasculature without the aid of a guide device (e.g., a guidewire or a guide catheter). In other examples, the user may use a guide catheter within which the flexible catheter <NUM> may be inserted to the target location. Alternatively, or additionally, the user may use a guidewire (e.g., the guidewire <NUM>) to navigate the flexible catheter <NUM> to a target location within the patient and remove the guidewire from the catheter <NUM> prior to delivering the medical adhesive <NUM>.

Once the flexible catheter <NUM> is positioned at the target location, the user may advance shaft <NUM> through at least a portion of the lumen of the flexible catheter <NUM> to force at least a first portion of the volume of medical adhesive <NUM> (e.g., a bolus) out of distal opening <NUM> of the lumen of the flexible catheter <NUM> (<NUM>). The user may then apply pressure to the tissue above the target location that received the first portion of medical adhesive to collapse the vein and set the medical adhesive (<NUM>). If there is another target location within then vein ("YES" branch of block <NUM>), then the user may proximally withdraw the flexible catheter <NUM> and position the distal end of the flexible catheter <NUM> at the new target location (<NUM>). The user may then advance shaft <NUM> further through the lumen of the flexible catheter <NUM> in order to deliver a second portion of the volume of medical adhesive <NUM> to the section target location of the vessel (<NUM>). This process may be repeated until the entire length of the vessel has been coapted with medical adhesive <NUM>. If there is no other target area to be treated by medical adhesive <NUM> ("NO" branch of block <NUM>), then the user may remove the flexible catheter <NUM> and shaft <NUM> (e.g., part of the mandrel) from the patient (<NUM>).

In some examples, the volume of medical adhesive <NUM> delivered from the flexible catheter <NUM> may be within a range from approximately <NUM> to approximately <NUM>. This volume may be different for the treatment of different vessels. For example, treatment of the greater saphenous vein may require a larger volume of medical adhesive than treatment of a perforator vein. Therefore, different flexible catheters may be pre-filled with different volumes of medical adhesive such that some pre-filled flexible catheters may be specified for treatment of certain vessels. These different available volumes may reduce medical adhesive waste for smaller vessels or smaller treatment areas.

<FIG> is a flow diagram of an example technique for inserting a pre-filled cartridge containing a vein-occluding substance in a catheter lumen and advancing a shaft through the catheter lumen to deliver a volume of vein-occluding substance out of the pre-filled cartridge and the catheter. For illustrative purposes, the techniques of <FIG> are described with reference to the various aspects of the flexible catheter <NUM> and the shaft <NUM> of <FIG>, <FIG>. However, such descriptions are not intended to be limiting and the techniques of <FIG> may be used with other devices or systems, such as flexible catheters <NUM>, <NUM>, <NUM>, <NUM>, the shaft <NUM>, and/or the mandrel <NUM>.

As shown in the example of <FIG>, a user may insert or deliver a distal end of the flexible catheter <NUM> to a target location within a hollow anatomical structure of a patient, such as a vein (<NUM>). In some examples, a user may use an ultrasound transducer to visualize the target location and distal end of the flexible catheter <NUM>. In some examples, the user may insert the flexible catheter <NUM> without the aid of other devices. For example, reinforcing member <NUM> or other structural features of the flexible catheter <NUM> may increase the structural integrity and pushability of the catheter <NUM> to enable the catheter <NUM> to be navigated through the vasculature without the aid of a guide device (e.g., a guidewire or a guide catheter). In other examples, the user may use an introducer catheter, guide catheter, or needle within which the flexible catheter <NUM> may be inserted to the target location. Alternatively, or additionally, the user may insert a guidewire (e.g., guidewire <NUM>) to navigate the flexible catheter <NUM> to the target location and then slide flexible catheter <NUM> over the guidewire and remove the guidewire prior to delivering the medical adhesive <NUM>, as discussed with respect to <FIG>.

Once the flexible catheter <NUM> is positioned at the target location, the user may insert the pre-filled cartridge <NUM> that includes medical adhesive <NUM> into the flexible catheter <NUM> (<NUM>). Then, the user may advance the shaft <NUM> through at least a portion of lumen <NUM> of the flexible catheter <NUM> and the pre-filled cartridge <NUM> to force at least a first portion of the volume of medical adhesive <NUM> (e.g., a bolus) out of distal opening <NUM> of the pre-filled cartridge <NUM> and the distal end of the flexible catheter <NUM> (<NUM>). The user may then apply pressure to the tissue above the target location that received the first portion of medical adhesive to collapse the vein and set the medical adhesive (<NUM>). If there is another target location within then vein ("YES" branch of block <NUM>), the user may withdraw the flexible catheter <NUM> and position the distal end of the flexible catheter <NUM> at the new target location (<NUM>). The user may then advance the shaft <NUM> further through lumen <NUM> and the pre-filled cartridge <NUM> in order to deliver a second portion of the volume of medical adhesive <NUM> to the section target location of the vessel (<NUM>). This process may be repeated until the entire length of the vessel has been coapted with medical adhesive <NUM>. If there is no other target area to be treated by medical adhesive <NUM> ("NO" branch of block <NUM>), the user may remove the flexible catheter <NUM> and the shaft <NUM> (e.g., part of the mandrel) from the patient (<NUM>).

In some examples, the volume of medical adhesive <NUM> delivered from the pre-filled cartridge <NUM> may be within a range from approximately <NUM> mLto approximately <NUM>. This volume may be different for the treatment of different vessels. For example, treatment of the greater saphenous vein may require a larger volume of medical adhesive than treatment of a perforator vein. Therefore, pre-filled cartridges with different volumes of medical adhesive may be available for treatment of certain vessels. These different available volumes of the pre-filled cartridge <NUM> may reduce medical adhesive waste for smaller vessels or smaller treatment areas. In addition, in some examples in which all of medical adhesive <NUM> has been delivered but more target locations still need to be treated, the user may remove the shaft <NUM> from lumen <NUM> and insert a new the pre-filled cartridge <NUM> with medical adhesive into the flexible catheter <NUM> prior again advancing the shaft <NUM> (<NUM>).

Claim 1:
A medical assembly (<NUM>) comprising:
a flexible catheter (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) configured to be disposed within a hollow anatomical structure of a patient, wherein the flexible catheter (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) defines a lumen having a lumen cross-sectional dimension and a distal opening (<NUM>,<NUM>,<NUM>) of the lumen, and wherein the lumen is configured to contain a volume of medical adhesive (<NUM>); and
a shaft (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) defining a shaft cross-sectional dimension smaller than the lumen cross-sectional dimension of the lumen, wherein advancement of the shaft (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>) through at least a portion of the lumen forces at least a portion of the volume of medical adhesive (<NUM>) out of the distal opening (<NUM>,<NUM>,<NUM>) of the lumen,
characterised in that it further comprises the volume of medical adhesive (<NUM>) pre-filled within the lumen of the flexible catheter (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>).