Patent Application
20140018772
The present disclosure relates generally to medical devices. In particular, the present disclosure relates to catheters with anti-occlusion features suitable for use in vascular access procedures. More particularly, the catheters may be configured to reduce, minimize, or prevent the occlusion of blood flow resulting from thrombus or fibrin sheath formation.
The embodiments disclosed herein will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. These drawings depict only typical embodiments, which will be described with additional specificity and detail through use of the accompanying drawings in which:
For the purposes of promoting an understanding of the principles of the disclosure provided herein, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will be readily understood with the aid of the present disclosure that the components of the embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a variety of configurations. Thus, the following more detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the disclosure, but is merely representative of various embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
Devices, systems, and methods for use of a self-centering catheter with anti-occlusion features are described herein. The methods, systems, and devices disclosed are suited for use in connection with any medical device, equipment or machinery configured or used to provide a subject with a vascular-access procedure. For example, the catheter disclosed herein may be used in conjunction with any commercially available hemodialysis machine or equipment to provide an effective dialysis procedure to a subject.
The present disclosure provides a catheter with a non-linear configuration at least along a distal portion thereof that is implanted in a vascular structure of a subject. In some embodiments, the catheter discussed herein may be coupled to a dialysis machine to provide patients with end stage renal disease (ESRD) with hemodialysis treatments. Applications of the catheter may include long-term vascular access procedures, including, but not limited to, hemodialysis and apheresis. Applications in short-term vascular access procedures are also contemplated.
For use in vascular access procedures, the catheter is inserted percutaneously into the vascular system. To provide a patient with an effective dialysis treatment, a sufficient volume of blood over a period of time must be removed from the patient, effectively cleansed or purified, and returned to the patient. In addition, to facilitate an effective dialysis procedure, the catheters disclosed herein are configured to have two lumen parts, such that the contaminated blood and the cleansed blood are kept substantially separate. The first and second lumen parts provide flow out of and into the patient's vascular system. In one embodiment, the first lumen part aspirates blood from a blood vessel of a patient to a dialysis machine where it is processed to remove toxins or waste, and the second lumen part returns the cleansed or purified blood to the patient. In an alternative embodiment, the second lumen part aspirates blood from a blood vessel of the patient to a dialysis machine where it is cleansed to remove toxins or waste, and the first lumen part infuses the cleansed or purified blood into the patient.
As used herein, flow into the body is also referred to as “venous” flow, and flow out of the body is called “arterial” flow. In one embodiment, a lumen part that aspirates blood from a blood vessel of a patient may be referred to as an arterial lumen, and a lumen part that infuses blood into the patient may be referred to as a venous lumen.
A common problem associated with dual lumen catheters used for hemodialysis is the partial or complete occlusion of the distal tips due to thrombus and fibrin sheath formation. Thrombus and fibrin sheath formation around the distal tips of the catheter can partially or completely occlude the flow passages of the catheter, which may result in decreased flow rate and lowered efficiency of a dialysis procedure, or a substantial or complete loss in catheter function. The configurations of the catheters disclosed herein provide anti-occlusion features that reduce, minimize, or prevent the formation of thrombus or fibrin sheath around the distal tips of the catheter.
The non-linear distal portion of the catheter includes first and second lumen parts that each include at least one flow passage to permit fluid flow therethrough. The non-linear configuration of the distal portion improves delivery and return of the fluid from the vascular structure and assists to prevent the formation of thrombus or fibrin sheath that could impede catheter performance around the distal tips of the catheter. In some embodiments, the non-linear configuration of the distal portion is a substantially circular or double D-shaped configuration. In such an embodiment, the outer wall surface of the catheter or of the lumen parts limits continuous contact between the catheter and the vessel wall to two points on the catheter walls, and suspends the distal tips of the catheter in the flowing blood. In some embodiments, contact between the vessel wall and the distal portion of the catheter is substantially limited to an apex of a concave bend with respect to the longitudinal axis of the first lumen, and an apex of a concave bend with respect to the longitudinal axis of the second lumen. This configuration allows the catheter to be inserted into a blood vessel of a patient, such that the substantially double D-shaped or circular configuration of the distal portion centers the distal tips of the catheter within the vessel lumen and away from the vessel wall, which minimizes or prevents thrombus or fibrin sheath formation around the distal tips of the catheter.
Shown in
As illustrated herein, the lumen parts 110, 120 of the catheter 100 may be configured to center the distal tips 114, 124 in the vessel, such as the superior vena cava (SVC), and away from the vessel walls of the patient to reduce, minimize, or prevent thrombus or fibrin sheath formation around the distal tips 114, 124 of the catheter 100. In some embodiments, the catheter 100 can be configured such that even if the distal portion 112 of the catheter 100 were to be inserted through the lumen of the SVC and placed in the right atrium, the substantially non-linear configuration of the lumen parts 110, 120 along length L and the parallel, substantially linear profile of the distal tips 114, 124 extending along the longitudinal axis 104 from the convergence 108 are likely to reduce, minimize, or prevent the occlusion of the flow passages 132, 142 of the distal tips 114, 124.
The catheter 100 can be fabricated from any suitable bio-compatible material, including, but not limited to, silicone, polyurethane, polyurethane-polycarbonate copolymer, or any other plastic or polymer material. The catheter 100 may also include an anti-microbial or anti-infection agent coating, such as silver, chlorhexidine, rifampin, minocycline, methylene blue, and the like.
The catheter 100 can be of any suitable size for placement in a vessel structure. It will be appreciated by those of skill in the art having the benefit of this disclosure that the size of the catheter 100 may be configured to fit within a vessel. In certain embodiments relating to dialysis, the catheter size may be between about 13 to about 16 French circumference. In other embodiments relating to infusing fluid and drawing blood samples from the central veins, the catheter size may be between about 5 to about 12 French circumference. Other catheter sizes are also contemplated.
The configuration of the catheter 100 may be manipulated to facilitate placement of the catheter 100 in a subject. In some embodiments, the double D-shaped or circular configuration of the catheter 100 is compressible, such that catheter 100 may be compressed into a substantially linear profile. In one embodiment, the catheter 100 may be compressed into a substantially linear profile using a sheath. The catheter 100 may be inserted into a sheath and threaded through the patient's vasculature for placement in the desired blood vessel, such as the SVC. In an alternative embodiment, the catheter 100 may be placed over a single guidewire or dual guidewires, with or without stylets, to facilitate placement of the catheter 100 in a subject.
For example, the first lumen part 110 forms a first portion 116 that extends from bifurcation 106 along a bend defined by radius R1 to a first apex 107. The second lumen part 120 forms a first portion 126 that extends from bifurcation 106 along a bend that is defined by radius R2 to a second apex 117. Radii R1 and R2 are located on the side of the respective lumen parts 110, 120 away from the longitudinal axis 104 so that the lumen parts 110, 120 separate and diverge distally away from the longitudinal axis 104 and form a convex relationship toward the longitudinal axis 104. Radius R1 and radius R2 can be the same, or can differ from one another.
The first lumen part 110 also includes a second portion 118 forming a reverse curve-like shape relative to the first portion 116 from the first apex 107. The second portion 118 extends from the first apex 107 along a bend defined by a radius R3 to the convergence 108. The second lumen part 120 also includes a second portion 128 that forms a reverse curve-like shape relative to the first portion 126. The second portion 128 extends from the second apex 117 along a bend defined by a radius R4 to the convergence 108. Radii R3 and R4 are located toward the longitudinal axis 104 and form a concave relationship oriented toward the longitudinal axis 104. Radius R3 and radius R4 can be the same, or can differ from one another.
The lumen parts 110, 120 contact at the convergence 108 and extend distally in a parallel, substantially linear profile along the longitudinal axis 104 to form the distal tips 114, 124. In some embodiments, the convergence 108 of the lumen parts 110, 120 may be formed by radii R5 and R6. Radii R5 and R6 are located on the side of the respective lumen parts 110, 120 away from the longitudinal axis 104 so that the lumen parts 110, 120 converge distally and form a convex relationship toward the longitudinal axis 104. Radius R5 and radius R6 can be the same, or can differ from one another. The lumen parts 110, 120 contact at the convergence 108 and extend distally in a parallel, substantially linear profile to form the distal tips 114, 124 of the catheter 100.
The triple-bend configuration of distal portion 112 provides a non-linear profile that assists in preventing or inhibiting the formation of a thrombus or fibrin sheath that encases the distal portion 112 and/or the distal tips 114, 124 when placed in a the body of a subject. The diverging and converging relationship between the lumen parts 110, 120 provides a non-linear profile for the lumen parts 110, 120 along the distal portion 112. It can be appreciated by those of skill in the art having the benefit of this disclosure that the bends are curved along a radius or radii to provide a smooth transition between the first portions 116, 126 and the second portions 118, 128 of the catheter 100 to prevent or reduce the formation of sharp bends or kinks in the lumen parts 110, 120 that could restrict or prevent flow through the flow passages 132, 142 thereof. In some embodiments, the divergence and convergence of the first lumen 110 and second lumen 120 form concave bends along the lumen parts 110, 120 with respect to the longitudinal axis 104 of the catheter 100.
The radii R1, R2, R3, R4, R5, and R6 are provided as examples of the curvature of the bends of the lumen parts 110, 120. The radii R1, R2, R3, R4, R5, and R6 may be any measurement capable of maintaining a suitable flow rate for hemodialysis through the flow passages 132, 142 of the lumen parts 110, 120. In one embodiment, the radii R1, R2, R3, R4, R5, and R6 are the same. In another embodiment, the radii R1, R2, R3, R4, R5, and R6 differ from one another. In an alternative embodiment, a combination of radii R1, R2, R3, R4, R5, and R6 have the same measurement, while the remaining radii differ in measurement. In particular embodiments, the radii R1, R2, R3, R4, R5, and R6 are configured to achieve or maintain a flow rate of about 300 mL/min. In one embodiment, radii R1, R2, R3, R4, R5, and R6 can each independently range from between about 0.5 to about 3.0 centimeters. In another embodiment, radii R1, R2, R3, R4, R5, and R6 can each independently range from between about 0.5 to about 1.5 centimeters.
The lengths of the distal tips 114, 124 are parallel to each other and extend along the longitudinal axis 104 of the catheter 100. In some embodiments, the first distal port 115 of the first distal tip 114 and the second distal port 125 of the second distal tip 124 are obliquely oriented relative to the longitudinal axis 104 of the catheter 100. The acutely angled side 133 of the first distal tip 114 is disposed adjacent to the acutely angled side 143 of the second distal tip 124, while the first distal tip 114 projects distally from the second distal tip 124 along the longitudinal axis 104 of the catheter 100. In certain embodiments, the distance of separation between the first distal tip 114 and the second distal tip 124 along the longitudinal axis 104 is about 0.5 inches. In some embodiments, the longitudinal separation between first 114 and second 124 distal tips ranges between zero to 1.0 inches, such as from 0.25 to 0.75 inches. Other longitudinal separation between the first 114 and second 124 distal tips are also contemplated. In one embodiment, the kinetic energy of the blood flowing out of the venous lumen delivers it away from the inflow of the arterial lumen, such that there is no demonstrable recirculation. In yet another embodiment, the catheter 100 is configured to have a longitudinal separation that results in minimal or no demonstrable recirculation at about 200 to about 400 mL/min flow in the middle of the fluid simulating the flow of blood in the middle of the vena cava. In some embodiments, no demonstrable recirculation can be, for example, less than about 1% recirculation, less than about 3% recirculation, and less than about 5% recirculation. In particular embodiments, the distance of separation between the distal tips 114, 124 along the longitudinal axis 104 may be configured to achieve or maintain a flow rate of at least about 300 mL/min through the catheter 100.
In an embodiment of a method or system for providing hemodialysis procedure to a patient, a dialysis machine (not shown) may be coupled to the catheter 100, and the catheter 100 may be coupled to a patient. The flow passages 132, 142 of the catheter 100 maintain fluid communication between the dialysis machine and the patient. In one embodiment, the first lumen part 110 aspirates blood from a blood vessel of the patient to a dialysis machine where it is processed to remove toxins or waste, and the second lumen part 120 returns the cleansed or purified blood to the patient. In another embodiment, the second lumen part 120 aspirates blood from a blood vessel of the patient to a dialysis machine where it is cleansed to remove toxins or waste, and the first lumen part 110 returns the cleansed or purified blood to the patient.
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The first lumen part 210 also includes a second portion 218 that forms a reverse curve-like shape relative to the first portion 216. The second portion 218 of the first lumen part 210 extends along a bend defined by a radius R3 to the convergence 208. The second lumen part 220 also includes a second portion 228 that forms a reverse curve-like shape relative to the first portion 226. The second portion 228 of the second lumen part 220 extends along a bend defined by a radius R4 to the convergence 208. Radii R3 and R4 are located toward the longitudinal axis 204 and form a concave relationship toward the longitudinal axis 204. Radius R3 and radius R4 can be the same, or can differ from one another.
The lumen parts 210, 220 are configured to contact at the convergence 208 and extend distally in a parallel, substantially linear profile along the longitudinal axis 204 to form the distal tips 214, 224. The convergence 208 of the lumen parts 210, 220 may be formed by radii R5 and R6. Radii R5 and R6 are located on the side of the respective lumen parts 210, 220 away from the longitudinal axis 204 such that the lumen parts 210, 220 converge distally and form a convex relationship toward the longitudinal axis 204. Radius R5 and radius R6 can be the same, or can differ from one another. The lumen parts 210, 220 contact at the convergence 208 and extend distally in a parallel, substantially linear profile to form the distal tips 214, 224 of catheter 200.
It will be appreciated by those of skill in the art having the benefit of this disclosure that the orientation of the distal ports 215, 225 can be modified. In certain embodiments, the distal ports 215, 225 of the catheter 200 are cut at the same angle. It will also be appreciated by those of skill in the art that the distance of separation between the distal tips 214, 224, along the longitudinal axis 204, can be modified. As is similar to
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The distal tips 214, 224 extending from the convergence 208 may be coupled or secured to one another with an adhesive, an extrusion technique, fusion, mechanical fasteners, and the like. In some embodiments, the distal tips 214, 224 are coupled or secured using a bond material with low adhesion strength. In certain embodiments, the bond between distal tips 214, 224 is weaker than a bond between proximal portions of the first 210 and second 220 lumen parts. In other embodiments, the distal tips are disposed adjacent to each other without being coupled or secured to one another. In yet another embodiment, the distal tips are held in place using wires or stiffening mechanisms inserted through the length of the catheter walls.
The lumen parts 310, 320 proximal of bifurcation can be coupled or secured to one another using an adhesive, an extrusion technique, fusion, mechanical fastener, and the like. In some embodiments, the lumen parts 310, 320 proximal of bifurcation can be heat-welded together at approximately 230° F.
The lumen parts 310, 320 distal of convergence may also be coupled to one another using an adhesive, extrusion technique, fusion, mechanical fasteners, and the like. In some embodiments, the lumen parts 310, 320 distal of convergence may be coupled using a bonding material with low adhesion strength, such that the adhesion strength is less than that of the lumen parts 310, 320 proximal of the bifurcation. In an alternative embodiment, the lumen parts 310, 320 distal of convergence may be disposed in a side-by-side relation along the longitudinal axis of the catheter without coupling the lumen parts 310, 320 to one another.
In yet another embodiment, the lumen parts 310, 320 distal of convergence may be held in position using wires or stiffening mechanisms (not shown) inserted through the length of the catheter walls 330, 340. The wires or stiffening mechanisms may be of varying sizes and lengths suitable for use in this context. In one embodiment, the wires or stiffening mechanisms may be incorporated into the catheter walls 330, 340 along the distal portion of the catheter 300. In some embodiments, the wires or stiffening mechanisms are incorporated into the catheter walls 330, 340 along the double D-shaped or circular configuration of the distal portion. The double D-shaped or circular configuration of the distal portion including the wires or stiffening mechanisms may be flexible. In certain embodiments, the double D-shaped or circular configuration of the distal portion may be compressed into a substantially linear profile, which may aid with placing the catheter in a subject.
Various arrangements for the distal tips are contemplated. In one embodiment, the configurations of the respective lumen parts 310, 320 shown in
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The first lumen part 510 also includes a second portion 518 that forms a reverse curve-like shape relative to the first portion 516. The second portion 518 of the first lumen part 510 extends from the first apex 507 along a bend defined by a radius R3 to the convergence 508. The second lumen part 520 also includes a second portion 528 that forms a reverse curve-like shape relative to the first portion 526. The second portion 528 of the second lumen part 520 extends from the second apex 517 along a bend defined by a radius R4 to the convergence 508. Radii R3 and R4 are located toward the longitudinal axis 504 and form a concave relationship oriented toward the longitudinal axis 504.
The lumen parts 510, 520 are configured to contact at the convergence 508 and extend distally in a parallel, substantially linear profile along the longitudinal axis 504 to form the distal tips 514, 524. The convergence 508 of the lumen parts 510, 520 may be formed by radii R5 and R6. Radii R5 and R6 are located on the side of the respective lumen parts 510, 520 away from the longitudinal axis 504 such that the lumen parts 510, 520 converge distally and form a convex relationship toward the longitudinal axis 504.
As shown in
Throughout this specification, any reference to “one embodiment,” “an embodiment,” or “the embodiment” means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification, are not necessarily all referring to the same embodiment.
Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim requires more features than those expressly recited in that claim. Rather, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. It will be apparent to those having skill in the art that changes may be made to the details of the above-described embodiments without departing from the underlying principles set forth herein.
