Patent Application
20240277361
The present disclosure generally relates devices and methods for removing acute blockages from blood vessels during intravascular medical treatments. More specifically, the present disclosure relates to aspiration retrieval catheters into which an object or objects can be retrieved.
Clot retrieval aspiration catheters and devices are used in mechanical thrombectomy for endovascular intervention, often in cases where patients are suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing the neurovascular bed is challenging with conventional technology, as the target vessels are small in diameter, remote relative to the site of insertion, and highly tortuous. These catheters are frequently of great length and must follow the configuration of the blood vessels in respect of all branching and windings. Traditional devices are often either too large in profile, lack the deliverability and flexibility needed to navigate particularly tortuous vessels, or are not effective at removing a clot when delivered to the target site.
As a result, there remains a need for improved catheter designs that refine current methods for improving the lateral flexibility of the catheter to improve the trackability of the catheter. The presently disclosed designs are aimed at providing an improved catheter having improved deliverability and flexibility needed to navigate particularly tortuous vessels. The presently disclosed designs also provide a catheter having a braided metal wire reinforcing layer capable of improving visibility of the catheter under fluoroscopy, while still being flexible, including at the distal end of the catheter, to improve the trackability of the catheter as it navigates tortuous vessels.
For vascular catheters to reach their target site a catheter is made such that, at its proximal end, the catheter is designed to be relatively stiff and gradually becomes less stiff/more flexible at the catheter distal end. This is mainly achieved by using harder materials proximally (Rockwell D from 180 to 90) and softer materials distally (Rockwell≤35D to Shore 72A to 30A) for the outer jacket materials. Vascular catheters are navigated within vessels, such as, for example, in the human anatomy, with the aid of fluoroscopic imaging which utilizes x-rays. However, the polymers of catheters do not attenuate x-ray very well as the catheter is not visible under fluoroscopy. Any metal components of the catheter body, for example, a braided or coiled wire reinforcement layer, are not significantly radiopaque. Stainless steel grades, such as, for example, 304, 316, 404, etc. are often used as the braid material. However, stainless steels are moderately radiopaque but not to the level clinically acceptable to behave as a marker band. For this reason, conventional catheters incorporate a highly x-ray attenuating metal marker, called a marker band, at the very distal tip of the catheter.
For most catheter designs the metal of choice is a stainless-steel grade (304, 316, 404, etc.). Stainless-steels are moderately radiopaque but not to the level that is clinically acceptable to function as a marker band. These braid wires could be made from more radiopaque materials such as platinum, however platinum does not resist deformation very well. Catheters having platinum braids are not very springy to recover to their original shape after being deformed and are instead rather easily plastically deformed. Therefore, catheters having platinum braids do not have the mechanical structure to be used as in vascular catheters.
The catheter in accordance with the present disclosure, allows visualization of the entire length of the catheter. The catheter allows a medical practitioner to adjust their navigation technique with visual cues. Therefore, as all regions of the catheter traverse anatomy, a medical practitioner can adjust the way she or he pushes or pulls the catheter and accessories based on visible feedback of the entire length of the catheter which permits visualization of how the shaft is bending at any point along the radiopaque shaft of the catheter.
Because the entire length of the catheter in accordance with the present disclosure, is visible under fluoroscopy, there is no need for a separate ridged marker band at the distal end of the catheter. The distal tip of the catheter in accordance with the present disclosure is radiopaque due to a compression of the braid at the distal end of the catheter. This structure allows for a radiopaque tip that is also flexible at the distal end of the catheter. Thus, the catheter in accordance with the present disclosure provides a better and more seamless navigation through tortuous anatomy. The distal end of the catheter in accordance with the present disclosure does not include a separate radiopaque marker band but instead relies on a continuous section of the braid component itself to provide a catheter design. Thus, the catheter in accordance with the present disclosure, allows visualization of the entire length of the catheter and even greater visualization at the distal end without the need for a separate, rigid marker band. In some examples, the rigid marker band of a conventional catheter can become detached from the rest of the catheter and remain in the vasculature during use of the catheter.
In some examples, a catheter in accordance with the present disclosure is disclosed for treating aneurysms. The catheter can include a liner having a proximal end, a distal end, an outer surface, and an internal lumen extending from the proximal end to the distal end along a longitudinal axis A. A braid is disposed on the outer surface of the liner and extends from the proximal end to the distal end of the liner. The braid comprises a plurality of wires wherein a first portion of the wires are made from tungsten and a second portion of the wires are made from a different material. A jacket is disposed about the braid and extends from the proximal end to the distal end.
The above and further aspects of this disclosure are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the disclosure. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.
The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Although the description of the disclosure is in many cases in the context of treatment of intracranial arteries, the disclosure may also be used in other body passageways as previously described.
As used herein, the terms “about” or “approximately” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein. More specifically, “about” or “approximately” may refer to the range of values ±20% of the recited value, e.g. “about 80%” may refer to the range of values from 61% to 99%.
As discussed herein, a “patient” or “subject” can be a human or any animal. It should be appreciated that an animal can be a variety of any applicable type, including, but not limited to, mammal, veterinarian animal, livestock animal or pet-type animal, etc. As an example, the animal can be a laboratory animal specifically selected to have certain characteristics similar to a human e.g., rat, dog, pig, monkey, or the like.
By “comprising” or “containing” or “including” is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, other exemplary examples include from the one particular value and/or to the other particular value.
Accessing cerebral, coronary and pulmonary vessels involves the use of a number of commercially available products and conventional procedural steps. Access products such as guidewires, guide catheters, angiographic catheters and microcatheters are described elsewhere and are regularly used in catheter lab procedures. It is assumed in the descriptions below that these products and methods are employed in conjunction with the device and methods of this disclosure and do not need to be described in detail.
Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.
A catheter in accordance with the present disclosure includes an inner lumen liner comprising a first polymer material, a braided metal wire jacket comprising a plurality of metal wires, and an outer liner comprising a second polymer material that may be the same or different from the first polymer material. A portion of the plurality of metal wires are made of tungsten and a portion of the plurality of metal wires are made of stainless steel. Tungsten is visible under fluoroscopy and provides a user with visual feedback of the entire catheter length when tracking a catheter in the vasculature. In addition, the braid is made with a higher pic count adjacent to the distal end to provide increased visibility at the distal end but without the disadvantages of using a rigid marker band.
Referring now to
Refractory metal/alloys such as Tungsten (W), MoRe, NbHf, NbW, VTa, or more generally Period 6 metals from the periodic table are very radiopaque. Many of these alloys are so hard that when incorporated into a braid they result in a mechanically strong metal backbone that has a very elastic or springy properties. That is, a catheter having braid wires, of which at least a portion of the braid wires are made from a Period 6 metal resists radial loads when in configured in a tubular braid. The catheter in accordance with the present disclosure incorporates such a metal as some of the braided wires to achieve clinically relevant radiopacity. This increase in radiopacity is further achieved by compressing the braid as much as the braid wire diameters will allow in a distal most section of the braid to form a braided marker-band.
The first portion of wires 24 is about half of the total number of wires and the second portion of the wires 26 is also about half of the total number of wires. In one example of the disclosure, the first portion of the wires 24 comprises eight wires and the second portion of the wires 26 comprises eight wires.
Liner 12 is made of PTFE in one example of the present disclosure. Jacket 28 is made of a polymer material in one example of the present disclosure. As shown in
Braid 22 has a plurality of different pic rates along the longitudinal axis A of braid 22. In one example, braid 22 has at least four axial sections 32, 34, 36, 38 extending from the distal end 16 to the proximal end 14. The at least four axial sections include a first most distal section 32, a second distal section 34 adjacent to the first most distal section, a third distal section 36 adjacent to the second distal section, and a fourth proximal most section 38 adjacent to the third distal section 36. The second distal section 34 being between the first distal section 32 and the third distal section 38. The third distal section 36 being between the second distal section 34 and the fourth distal section 38. The fourth most proximal section 38 being adjacent to the third distal section 36.
Each braid section 32, 34, 36, 38 has a different pic rate. Braid first distal most section 32 has a pic rate of about 330 picks per inch (“ppi”). Braid first distal section 32 has an axial length of about 0.010 inches to about 0.039 inches. Braid second distal section 34 has a pic rate of about 105 ppi. Braid second distal section 34 has an axial length of about 7.87 inches. Braid third distal section 36 has a variable pic rate of about 105 ppi to about 195 ppi. Braid third distal section 36 has a variable pic rate of about 105 ppi adjacent to a proximal end of the third distal section to about 195 ppi adjacent to a distal end of the third distal section. Braid third distal section 36 has a variable pic rate that transitions continuously from the proximal end of the third distal section to the distal end of the third distal section. Braid third distal section 36 has an axial length of about 7.87 inches. Braid fourth proximal section 38 has a pic rate of about 195 ppi. Braid fourth proximal section 38 has an axial length of about 44.0 inches.
Referring now to
Catheter 10 has in an example of the present disclosure an inner diameter of about 0.092 inches from its proximal end 14 to its distal end 16. Catheter 10 also has, in an example of the present disclosure, an outer diameter that tapers from an outer diameter of about 0.108 inches at proximal end 14 down to about 0.101 inches at distal end 16. Catheter 10, in an example of the present disclosure, can have various working lengths, such as, for example, of about 114 cm, or about 122 cm, or about 130 cm, or about 135 cm. Catheter 10 can also have a hydrophilic coating on its inner diameter for a length of about 50 cm extending from distal end 16 toward the proximal end.
Referring now to
Referring now to
Aspects of the disclosure are also provided by the following numbered clauses:
The descriptions contained herein are examples of embodiments of the disclosure and are not intended in any way to limit the scope of the disclosure. As described herein, the disclosure contemplates many variations and modifications of a catheter. Modifications and variations apparent to those having skilled in the pertinent art according to the teachings of this disclosure are intended to be within the scope of the claims which follow.
This application claims the benefit of U.S. Provisional Application No. 63/447,523 filed Feb. 22, 2023, the disclosure of which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63447523 | Feb 2023 | US |
