Patent Application
20170368318
The invention, in some embodiments, relates to the field of balloon catheters and more particularly, but not exclusively, to intravascular balloon catheters.
Stenosis, or the narrowing of a blood vessel lumen due to the formation of a lesion (e.g. deposits such as cholesterol, fats, and calcium) is a medical condition common in both women and men over 50. In some cases, such as in a resultant formation of a blood clot in a coronary artery, the condition may turn life-threatening.
One standard technique for the removal of a lesion in a blood vessel lumen is balloon angioplasty. A balloon catheter is inserted into the blood vessel and guided therein until the balloon is adjacent to the lesion. The balloon is then inflated, thereby compressing the lesion.
A related technique is that of stenting. A stent carried on the balloon is expanded against the blood vessel walls as the balloon is inflated. When the balloon is deflated and pulled out, due to the stent's plasticity, the stent remains in place and prevents the blood vessel from reassuming its original shape (e.g. decompressing). Drawbacks include the risk of formation of blood clots, and the growth of scar tissue due to an immune response to the foreign body (the stent).
Other techniques include atherectomy, the insertion of a catheter including blades, which are used to cut up the lesion, and laser ablation, the insertion of a catheter including, for example, a laser heated optical fiber tip, which is used to disintegrate the lesion. As compared to balloon angioplasty, both of the latter techniques have the drawback of a higher risk of damaging the blood vessel walls.
Balloon angioplasty is also not devoid of drawbacks. In fact, about a third of patients undergoing angioplasty will return for a second angioplasty within six months due to a recurrence of stricture (restenosis). In standard balloon angioplasty, once on site, the balloon is inflated with fluid, resulting in a substantially equal pressure throughout the balloon, and, in particular, in substantially equal pressure being applied to the blood vessel walls. The lesion, however, will generally not be uniformly stiff, and will therefore not be uniformly compressed. This lack of uniform compression may lead to an undesirable on-site reshaping of the blood vessel walls, whereby their surfaces become wavelike (instead of smooth), increasing the chances of restenosis.
WO 2013/080213 to Teichman and Kotlizky discloses a balloon catheter system. The catheter includes a first balloon disposed around a second balloon which is movable within the first balloon.
U.S. Pat. No. 4,338,942 to Fogarty discloses a dilatation catheter with a double lumen tube and inner and outer inflatable and deflatable balloon elements, one within the other. The inner bag element is twisted for retraction while the outer bag element is inflated. Subsequent deflation of the outer bag element serves to further laterally compress the inner bag element and provide a smooth buffering surface for engagement with blood vessel walls as the catheter is moved past them.
There remains a need for improved methods for smoothing lesion material on a blood vessel wall without leading to adverse effects.
To overcome the shortcomings listed above, there is disclosed herein a balloon catheter including a work element housed within an inflatable balloon. The work element is configured to allow applying an outward force on a target area on a surface of the balloon when the balloon is inflated and anchored within a blood vessel. When the balloon catheter is anchored within an intraluminal passage with the work element facing a target lesion on a blood vessel wall, the work element may be lifted such as to press against the target lesion (or a region thereon), thereby compressing and possibly smoothing lesion material on the blood vessel wall. Advantageously, the balloon surface protects the blood vessel walls from direct contact with the work element, thereby decreasing the risk of damage to tissue. The amount of force exerted by the work element may be controllably varied according to characteristics of the lesion, including the stiffness thereof and the shape of the surface thereof. The selective application of force has the advantage of allowing for the resulting lesion material pattern to be smooth rather than wavelike, and, as a further advantage, may eliminate the need for a stent.
Thus, according to an aspect of the present invention, there is provided a catheter system. The catheter system includes:
The guidewire is controllably switchable between a guiding configuration, for maneuvering the catheter system through intraluminal passages, and a work configuration, in which the at least one work element radially projects relative to a longitudinal axis of the balloon and pushes against a surface of the balloon when the balloon is inflated with fluid and anchored in an intraluminal passage. The at least one work element is non-expandable.
According to some embodiments of the catheter system, the at least one work element includes a lesion-smoothing member. The lesion-smoothing member is a rigid or resiliently flexible surface or a rigid or resiliently flexible wire.
According to some embodiments of the catheter system, in the guiding configuration the at least one work element substantially does not project relative to the longitudinal axis.
According to some embodiments of the catheter system, the guidewire is continuously switchable between the guiding configuration and the work configuration, thereby allowing to control the amount of projection of the at least one work element and the amount of force exerted by the at least one work element against the balloon surface when the balloon is inflated with a fluid and anchored in an intraluminal passage.
According to some embodiments of the catheter system, the at least one work element is further configured to allow for controllable rotation about the longitudinal axis, such as to allow the lesion-smoothing member to slide along the balloon surface and simultaneously push there against when the guidewire is in the work configuration and the balloon is inflated with a fluid and anchored in an intraluminal passage; and/or
the at least one work element is further configured to allow for reciprocal motion, such as to allow the lesion-smoothing member to substantially proximally and distally slide along the balloon surface and simultaneously push there against when the guidewire is in the work configuration and the balloon is inflated with a fluid and anchored in an intraluminal passage.
According to some embodiments of the catheter system, the at least one work element is configured to allow for controllable rotation about the longitudinal axis. The controllable rotation is effected by rotating the proximal segment.
According to some embodiments of the catheter system, the mounting of the balloon distal end on the distal segment is such as to prevent any proximal and distal motion of the balloon distal end relative to the distal segment.
According to some embodiments of the catheter system, the catheter system is further configured to allow switching from the guiding configuration to the work configuration by distally pushing the proximal segment when the balloon is anchored.
According to some embodiments of the catheter system, the distal segment includes an exposed segment and a non-exposed segment, located outside of the balloon and within the balloon, respectively. The exposed segment includes a pliable tip at a distal end thereof.
According to some embodiments of the catheter system, the tube distal end includes a first bearing mounted thereon and connected to the balloon proximal end. The proximal segment passes through the first bearing. The distal segment includes a second bearing mounted thereon and connected to the balloon distal end. The first bearing and the second bearing are configured to allow rotating the guidewire without rotating the tube and the balloon. The first bearing is further configured to allow proximal and distal motion therethrough of the proximal segment.
According to some embodiments of the catheter system, the proximal segment includes a first disc, mounted perpendicularly thereto and distally relative to the first bearing such as to be positioned adjacent thereto when the guidewire is in the guiding configuration. The distal segment includes a second disc and a third disc, mounted perpendicularly thereto and proximally and distally relative to the second bearing, respectively, such as to be positioned adjacent thereto.
According to some embodiments of the catheter system, the exposed segment and the non-exposed segment are mechanically associated via a ratchet within the second bearing. The ratchet is configured to allow for (i) joint rotation of the exposed segment together with the non-exposed segment, the at least one work element, and the proximal segment when the proximal segment is rotated in one sense, and (ii) rotation only of the non-exposed segment, the at least one work element, and the proximal segment when the proximal segment is rotated in the other sense.
According to some embodiments of the catheter system, the lesion-smoothing member is substantially convex.
According to some embodiments of the catheter system, the lesion-smoothing member is a convex surface. The at least one work element further includes a first arm, mechanically associating the convex surface on a proximal end thereof with the distal end of the proximal segment, and a second arm, mechanically associating the convex surface on a distal end thereof with the proximal end of the distal segment.
According to some embodiments of the catheter system, the catheter system further includes a first joining region connecting the proximal segment distal end to the first arm, a second joining region connecting the first arm to the convex surface proximal end, a third joining region connecting the convex surface distal end to the second arm, and a fourth joining region connecting the second arm to the distal segment proximal end. The joining regions include hinges, or the joining regions are more flexible than the proximal segment, the first arm, the convex surface, the second arm, and the distal segment, such as to allow the convex surface to be radially lifted when the proximal segment is pushed in the distal direction when the balloon is inflated with a fluid and anchored within an intraluminal passage.
According to some embodiments of the catheter system, each of the joining regions is notched.
According to some embodiments of the catheter system, the proximal segment, the work element, and the non-exposed segment are made of a single wire, which is substantially straight in the guiding configuration. The work element further includes a first arm and a second arm. A first joining region connects the proximal segment distal end to the first arm. A second joining region connects the first arm to a proximal end of the lesion-smoothing member. A third joining region connects a distal end of the lesion-smoothing member to the second arm. A fourth joining region connects the second arm to the distal segment proximal end. The joining regions are notched, with the notches of the first and fourth joining regions being located on the guidewire oppositely (relative to the longitudinal axis) to the second and third joining regions, such as to allow the lesion-smoothing member to be radially lifted when the proximal segment is pushed in the distal direction when the balloon is inflated with a fluid and anchored within an intraluminal passage.
According to some embodiments of the catheter system, the tube is fluidly connected to the balloon, and the tube proximal end is configured to be coupled to a fluid source or vacuum.
According to some embodiments of the catheter system, the catheter system further includes a duct fluidly connected at a distal end thereof to the balloon and configured to be coupled, at a proximal end thereof, to a fluid source or vacuum. The duct is longitudinally joined at least at a distal portion thereof to the tube.
According to some embodiments of the catheter system, the catheter system is further configured to allow for the controllable rotation to be effected by a motor and/or manually.
According to some embodiments of the catheter system, the intraluminal passage is a blood vessel.
According to some embodiments of the catheter system, the blood vessel is a coronary artery or vein.
According to some embodiments of the catheter system, the catheter system includes a plurality of the work element. The plurality of work elements are symmetrically disposed about the longitudinal axis of the balloon.
According to some embodiments of the catheter system, the convex surface is substantially flat.
According to some embodiments of the catheter system, when inflated, the balloon is shaped substantially as an ellipsoid or a cigar.
According to some embodiments of the catheter system, the proximal segment and the distal segment are further connected by a mechanical spring extending along the longitudinal axis.
According to some embodiments of the catheter system, the balloon is a drug-eluting balloon.
According to some embodiments of the catheter system, the work element includes radiographic markers.
According to a further aspect of the present invention, there is provided a method for treating blockage in intraluminal passages. The method includes the steps of:
Certain embodiments of the present invention may include some, all, or none of the above advantages. Further advantages may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein. Aspects and embodiments of the invention are further described in the specification hereinbelow and in the appended claims.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the patent specification, including definitions, governs. As used herein, the indefinite articles “a” and “an” mean “at least one” or “one or more” unless the context clearly dictates otherwise.
Some embodiments of the invention are described herein with reference to the accompanying figures. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments may be practiced. The figures are for the purpose of illustrative description and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the invention. For the sake of clarity, some objects depicted in the figures are not to scale.
In the Figures:
The principles, uses and implementations of the teachings herein may be better understood with reference to the accompanying description and figures. Upon perusal of the description and figures present herein, one skilled in the art will be able to implement the teachings herein without undue effort or experimentation. In the figures, like reference numerals refer to like parts throughout.
A first exemplary embodiment of a catheter system 100, as described herein, is schematically depicted in
Making reference also to
Hub 116 is mounted on the proximal ends of tube 110 and duct 112, i.e. tube proximal end 126 and duct proximal end 130, respectively. Guidewire port 120 is connected to tube 110 by a passageway (not shown) inside hub 116. Inflation port 122 is fluidly associated with duct 112. Tube 110 is connected to first bearing 140 at tube distal end 128. Duct 112 is longitudinally joined to tube 110, and is fluidly connected to balloon 108.
Balloon 108 has a generally cylindrical shape with curved or rounded edges, reminiscent of a cigar, when inflated and no external forces are acting thereon. According to some embodiments, balloon 108 may be shaped as an ellipsoid or a torpedo when inflated and no external forces are acting thereon. According to some embodiments, membrane 134 may be transparent, as depicted in the Figures.
Making reference to
According to some embodiments, catheter body 104 does not include duct 112. In such embodiments, tube 110 may be fluidly associated with inflation port 122, and, via first bearing 140, which is configured to allow passage of the fluid therethrough, with balloon 108. According to some embodiments, tube 110 and duct 112 are both housed within a single flexible tube (not shown).
Work element 158 is disposed within balloon 108. In
First bearing 140 is mounted on first segment 150. Second bearing 144 is jointly mounted on second segment 152 and third segment 154. First segment 150 includes a first disc 192, fixedly mounted thereon, inside balloon 108. Second segment 152 includes a second disc 194, fixedly mounted thereon, inside balloon 108, and adjacent to second bearing 144. Third segment 154 includes a third disc 196, fixedly mounted thereon, and adjacent to second bearing 144. First bearing 140 is mechanically barred from distal movement along first segment 150 beyond first disc 192. Second bearing 144 is mechanically barred from both proximal and distal movement relative to second segment 152 (and third segment 154) by second disc 194 and third disc 196, respectively.
As used herein, “distal direction” may refer to the direction along guidewire 102 pointing toward guidewire distal end 188. “Proximal direction” may refer to the direction along guidewire 102 pointing toward guidewire proximal end 186. “Distal movement” may refer to a movement along guidewire 102, or of guidewire 102, in the distal direction. “Proximal movement” may refer to a movement along guidewire 102, or of guidewire 102, in the proximal direction.
First bearing 140 and second bearing 144 are configured to allow guidewire 102 rotation—and, in particular, work element 158 rotation within volume A—independently of catheter body 104. That is to say, guidewire 102 may be rotated without catheter body 104 being simultaneously rotated. Ratchet 172 allows third segment 154 to jointly rotate with second segment 152 (and work element 158 and first segment 150), when second segment 152 is rotating in one sense (e.g. anti-clockwise), but bars third segment 154 from any rotation, when second segment 152 is rotating in the opposite sense (e.g. clockwise).
According to some embodiments, guidewire 102 does not include ratchet 172, and second segment 152 (and work element 158 and first segment 150) cannot be rotated independently of third segment 154. Further, in some such embodiments, second segment 152 and third segment 154 are integrally formed of a single piece of wire.
First bearing 140 and second bearing 144 are further configured such as to substantially prevent any passage of fluid therethrough, and, in particular, to substantially prevent escape therethrough of fluid from within balloon 108. According to some embodiments, first bearing 140 and second bearing 144 may each include O-rings (not shown) mounted on annular grooves therein (not shown), with guidewire 102 passing therethrough, thereby allowing for no passage of fluid through first bearing 140 and through second bearing 144, respectively. Except for being fluidly connected to duct 112, balloon 108 is fluidly, or substantially fluidly, sealed.
According to some embodiments, the “rated burst pressure” (RBP) of a catheter balloon is the maximum pressure at which 99.9% of substantially identical copies of the catheter balloon do not burst with a confidence level of 95%. According to some embodiments, a catheter balloon is “fully inflated” when the pressure therein equals the RBP. A “lateral cross-section” of a catheter balloon, which when inflated is substantially symmetric under rotations about a symmetry axis thereof (e.g. a cylindrical or cigar shaped catheter balloon), refers to a cross-section normal (i.e. perpendicular) to the symmetry axis, e.g. a cross-section of balloon 108 perpendicular to longitudinal axis B. According to some embodiments, the “nominal diameter” of a catheter balloon refers to the diameter of the highest-diameter lateral cross-section of the catheter balloon at “nominal pressure”. According to some embodiments, the “nominal pressure” may be 40% of RBP, or 50% of RBP, or even 60% of RBP. According to some embodiments, the “compliance” of a catheter balloon is defined as the change in the catheter balloon's diameter as a function of the pressure therein. The higher the compliance of a catheter balloon, the more deformable the catheter balloon's shape under application of external forces, when inflated. According to some embodiments, a catheter balloon is said to be “non-compliant” when the diameter of the catheter balloon remains unchanged at pressures above the nominal pressure (but lower than RBP). According to some embodiments, a catheter balloon is said to be “semi-compliant” when the diameter of the catheter balloon may change by up to 10% at pressures above the nominal pressure (but lower than RBP).
As used herein, according to some embodiments, a catheter balloon may be said to be inflated when a volume thereof is at least 67% of a volume thereof at RBP. According to some embodiments, a catheter balloon may be said to be deflated when a volume thereof is no more than 33% of the volume thereof at RBP.
According to some embodiments, the length of balloon 108, i.e. the distance between first bearing 140 and second bearing 144, may range from 1 cm (centimeter) to 6 cm, or from 2 cm to 5 cm, or even from 2 cm to 3 cm. According to some embodiments, the diameter of balloon 108 may range from 0.2 cm to 1 cm, or from 0.3 cm to 0.8 cm. According to some embodiments, balloon 108 is semi-compliant with RBP equaling 16 atm (atmosphere) or 20 atm, or even 24 atm, and the nominal pressure equaling 50% of RBP or even 60% of RBP. According to some embodiments, balloon 108 is non-compliant with RBP equaling 8 atm or 12 atm or even 14 atm, and the nominal pressure equaling 50% of RBP or even 60% of RBP.
Balloon 108 may be made of nylon, PVC (polyvinyl chloride), PET (polyethylene terephthalate), PP (polypropylene), latex, silicon, or the like, as known in the art.
According to some embodiments, the length of guidewire 102 may range from 1 m (meter) to 4 m. According to some embodiments, the length of guidewire 102 may range from 1.5 m to 2.5 m. According to some embodiments, the diameters of first segment 150 and second segment 152 may range from 0.02 cm to 0.1 cm. According to some embodiments, the diameters of first segment 150 and second segment 152 may range from 0.03 cm to 0.05 cm, or even from 0.033 cm to 0.037 cm. According to some embodiments, the length of third segment 154 may range from 2 cm to 5 cm, or from 3 cm to 4 cm. According to some embodiments, the diameter of third segment 154 may range from 0.02 to 0.1 cm or from 0.03 cm to 0.05 cm, or even from 0.033 cm to 0.037 cm. According to some embodiments, third segment 154 diameter may taper in the distal direction.
First segment 150, second segment 152, and third segment 154 are sufficiently stiff to allow guidewire 102 to be advanced through intraluminal passages in a subject's body, e.g. blood vessels, and at the same time are sufficiently flexible to allow guidewire 102 to be guided through bends therein the blood vessels. Depending on a target intraluminal passage, first segment 150, second segment 152, and third segment 154, may each have a different stiffness. First segment 150 and second segment 152 may be made of a flexible metal, as known in the art. Third segment 154 may be made of the same flexible metal, or another flexible metal. According to some embodiments, curved tip 182 includes a spring coil, as known in the art. According to some embodiments, each of first segment 150, second segment 152, and third segment 154 are made of a different material (e.g. a different flexible metal), respectively.
According to some embodiments, in the guiding configuration convex surface 210 projects radially from longitudinal axis B, with first arm 220 forming an angle α with first segment 150, and with second arm 230 forming an angle β with second segment 152. α and β may be substantially equal, assuming a value of 165°, 170°, 175°, or even 180°. When no external forces are exerted on guidewire 102, work element 158 is in the guiding configuration.
According to some embodiments, convex surface 210 is rigid. According to some embodiments, convex surface 210 is resiliently flexible. According to some embodiments, first arm 220 and second arm 230 are rigid. Joining regions 262, 264, 266, and 268 are each more flexible than first segment 150, second segment 152, first arm 220, second arm 230, and convex surface 210. According to some embodiments, joining regions 262, 264, 266, and 268 may be made of a more flexible material than first segment 150, second segment 152, first arm 220, and second arm 230 (and convex surface 210). According to some embodiments, joining regions 262, 264, 266, and 268 are narrower (thinner) than first segment 150, second segment 152, first arm 220, and second arm 230. According to some embodiments, joining regions 262, 264, 266, and 268 are notched, essentially as described in the description of
According to some embodiments, convex surface 210 is substantially non-expandable (e.g. in contrast to a balloon or a rubber band). As used herein, a solid object or element may be said to be “non-expandable” even while being resiliently flexible. A typical plastic clipboard (e.g. for writing) provides an example of a non-expandable yet resiliently flexible solid object. Another example is provided by a rubber hose (e.g. for hand-watering a garden).
To switch from the guiding configuration to the work configuration, a force in the distal direction may be applied on first arm 220 via first joining region 262. When balloon 108 is anchored within an intraluminal passage, due to second segment distal end 168 position being fixed and due to joining regions 262, 264, 266, and 268 having a smaller stiffness than first segment 150, second segment 152, first arm 220, second arm 230, and convex surface 210, joining regions 262, 264, 266, and 268 may bend such as to decrease α and β, thereby radially lifting convex surface 210 and simultaneously distally shifting convex surface 210. More specifically, according to some embodiments, the distal force applied on first arm 220 results in torques being applied respectively on first arm 220 and on second arm 230 (on second arm 230 via surface distal end 238), thereby lifting convex surface 210. According to some embodiments, values of α and β close to (but smaller than) 180° in the guiding configuration may help in preventing scenarios wherein either one of α and β, or both, increases under the applied force and convex surface 210 is not radially lifted. By varying the distal force exerted, the values of α and β may be controllably varied, and thereby the degree or amount of lifting of convex surface 210.
It is noted that by alternatingly simultaneously increasing α and β, and simultaneously decreasing α and β, a back-and-forth motion of work element 158 is effected. When the increase and decrease in α and β are sufficiently small, the back-and-forth motion will be mainly in parallel to longitudinal axis B, as elaborated on hereinbelow.
It is further noted that as convex surface 210 is lifted, α and β may decrease at different rates. For example, as first segment 150 starts being pushed, a may decrease (e.g. from 180° or) 175° at a faster rate than β, resulting in surface proximal end 234, at least initially, projecting further from longitudinal axis B than surface distal end 238. According to some embodiments, first arm 220 and second arm 230 do not have the same length. According to some embodiments, first arm 220 is shorter than second arm 230. According to some embodiments, joining regions 262 and 268 are further connected by a mechanical spring (similar to the mechanical in
To switch from the work configuration to the guiding configuration, the application of the distal force on first arm 220 is stopped (ceased). If necessary, a force in the proximal direction may be applied on first arm 220 via first joining region 262, thereby proximally pulling work element 158. According to some embodiments, when no forces are acting on work element 158, guidewire 102 is in the guiding configuration.
According to some embodiments, first segment 150 may be mounted through a chuck (not shown), as used in a drill, proximally located relative to hub 116. The chuck may be housed within a chuck housing (not shown). The chuck housing may be stationary, for example, being secured to an operating table, and thereby configured to prevent displacement of the chuck, particularly, proximal and distal displacement of the chuck, while simultaneously allowing the chuck to be rotated.
The chuck admits a locked configuration and an unlocked configuration. In the locked configuration, the chuck grips guidewire 102, thereby preventing guidewire 102 from distal and proximal motion. When the chuck is rotated, the chuck's grip on guidewire 102 causes guidewire 102 to be jointly rotated with the chuck. According to some embodiments, the chuck may be controllably rotated using an electric motor. According to some embodiments, the chuck may be controllably rotated manually. In the unlocked configuration, the chuck does not grip guidewire 102, and guidewire 102 distal and proximal motion are allowed. Rotation of the chuck does not induce guidewire 102 rotation, and guidewire 102 may be rotated independently of the chuck.
When guidewire 102 is in the guiding configuration, the chuck is unlocked. After guidewire 102 has been switched to the work configuration, the chuck may be locked, thereby preventing first segment 150 proximal movement, and, in particular, guidewire 102 return to the guiding configuration.
Other embodiments, allowing to controllably switch between the work configuration and the guiding configuration, are contemplated. According to some embodiments, joining regions 262, 264, 266, and 268 include one-way hinges (not shown). According to some embodiments, joining regions 262, and 268 include hinges restricting α and β to vary, for example, between 180° and 90°, or between 175° and 90°. Similarly, joining regions 264 and 266 may include hinges which restrict the ranges of the angles (not indicated) between first arm 220 and convex surface 210 and second arm 230 and convex surface 210, respectively.
According to some embodiments, work element 158 includes radiographic markers (not shown). According to some embodiments, some of the markers are located on outer face 240. Using standard imaging techniques known in the art, e.g. fluoroscopy, the markers may help in visualizing work element 158, including the location of convex surface 210 within balloon 108, when balloon 108 is inside an intraluminal passage.
According to some embodiments, e.g. wherein balloon 108 is compliant, in the work configuration, when balloon 108 is fully inflated outside an intraluminal passage, convex surface 210 does not push against internal surface 138, or is not in contact with internal surface 138 (as depicted for example in
As used herein, “lesion” may refer to an abnormality of/in an intraluminal passage resulting in stenosis, including the formation of cholesterol, fat, calcium deposits (e.g. plaque) and/or the like, the formation of blood clots, growth of scar tissue and/or the like within blood vessels. As used herein, “stenosis” may refer to a narrowing of an intraluminal passage, including blood vessels, and may be used interchangeably with stricture and blockage. As used herein, “blockage” may refer to an impediment to fluid flow in an intraluminal passage due to narrowing thereof, and according to some embodiments may be used interchangeably with “partial blockage”. As used herein, “blockage release” in a stenosed region of an intraluminal passage, may refer to a removal or partial removal of the impediment to the fluid flow (e.g. blood flow) in the stenosed region, e.g. in the broadening of the intraluminal passage in the stenosed region.
According to an aspect of some embodiments, there is provided a method for releasing stenosis in a target blood vessel, using catheter system 100 or a catheter system similar thereto (such as catheter systems 400, 500, and 800, disclosed hereinbelow). Throughout all the steps listed below, standard imaging techniques known in the art, e.g. fluoroscopy, may be used to visualize parts of guidewire 102 and catheter body 104 inside blood vessels. The method includes the following steps:
In a step I, balloon 108 is in a deflated state, containing a small amount of fluid (e.g. a saline 5% solution), and guidewire 102 is in the guiding configuration. Third segment 154 is inserted into a main blood vessel in the subject's body (e.g. a femoral artery in a leg of the subject (patient) when the target blood vessel is a coronary artery) and guided onto the target blood vessel.
According to some embodiments, third segment 154 may be advanced in a blood vessel by distally pushing first segment 150 from the outside of catheter body 104, i.e. pushing first segment 150 further into guidewire port 120. First segment 150 distal push is translated, via work element 158 and second segment 152, into third segment 154 distal push. As guidewire 102 is advanced in the blood vessel, second bearing 144, being distally pushed by second disc 194, pulls balloon 108 therewith. Balloon 108 pulls the rest of catheter body 104 (tube 110, duct 112 and hub 116).
According to some embodiments, third segment 154 may be advanced in the blood vessel by distally pushing tube 110 from outside the subject's body. Tube 110 distal push is translated via first bearing 140 into first disc 192 distal push, and, thereby, via first segment 150, work element 158, and second segment 152, into third segment 154 distal push. According to some embodiments, catheter system 100 does not include first disc 192 and third disc 196, and third segment 154 may be advanced by distally pushing first segment 150, as described hereinabove.
Third segment 154 may be guided into an opening of a second blood vessel, diverging from a first blood vessel, wherein curved tip 182 is located, by rotating anti-clockwise first segment 150 from the outside of catheter body 104. First segment 150 anti-clockwise rotation is translated via work element 158 and second segment 152 into third segment 154 anti-clockwise rotation. The rotation is continued until curved tip 182 points towards the opening of the second blood vessel. First segment 150, and/or tube 110, may then be distally pushed, causing third segment 154 to advance into the second blood vessel.
Third segment 154 is guided through a series of diverging blood vessels into the target blood vessel and advanced therein until balloon 108 reaches a stenosed target region in the target blood vessel (as schematically depicted in
In a step II, balloon 108 is inflated by pumping fluid therein via inflation port 122. When a sufficient amount of fluid has been pumped into balloon 108, membrane 134 comes into contact with the surrounding blood vessel walls (as schematically depicted in
According to some embodiments, balloon 108 may be fully inflated (i.e. up to RBP). According to some embodiments, balloon 108 may inflated to the nominal pressure. According to some embodiments, following inflation, balloon 108 may be partially deflated, such that a pressure within balloon 108 substantially equals 90% of the nominal pressure, 70% of nominal pressure, or even 40% of the nominal pressure. The partial deflation may increase the effective elasticity of balloon 108 and bring it to a desired level. The higher the compliance of balloon 108, the less deflation may be required to achieve the desired level of effective elasticity. According to some embodiments, balloon 108 may be inflated to a pressure as high as 24 atm. According to some embodiments, balloon 108 may be inflated to a pressure as low as 2 atm.
In a step III, guidewire 102 is distally pushed (i.e. into the main blood vessel and therefore further into the target blood vessel) by distally pushing first segment 150 from the outside of catheter body 104, i.e. pushing first segment 150 further into guidewire port 120. First segment 150 distal push is translated via work element 158, second segment 152, and second disc 194 to a distal push on second bearing 144, which in turn distally pulls on balloon 108. Since balloon 108 is inflated, balloon 108 is prevented from movement by surrounding blood vessel walls and lesions thereon, and, in particular, from distal movement (i.e. movement up the target blood vessel), and, consequently, so is second bearing 144. According to some embodiments, due to joining regions 162, 164, 166, and 168 being more flexible than first segment 150, first arm 220, convex surface 210, second arm 230, and second segment 152, as a result of the distal push on first segment 150, torques are applied on first arm 220 and second arm 230, respectively. Convex surface 210 is thereby radially lifted, bringing guidewire 102 into the work configuration, as explained hereinabove in the description of
As convex surface 210 is radially lifted, outer face 240 comes into contact with internal surface 138, thereby exerting pressure on membrane 134. The pressure on membrane 134 is translated into a radial (i.e. outward) force acting on an adjacent region of the target lesion.
According to some embodiments, guidewire 102 is mounted through a chuck, such as the chuck described hereinabove, and guidewire 102 may be prevented from returning to the guiding configuration by locking the chuck.
In a step IV, first segment 150 may be clockwise rotated. First segment 150 clockwise rotation is translated into work element 158 and second segment 152 clockwise rotation. Second segment 152 clockwise rotation is not translated into third segment 154 clockwise rotation due to ratchet 172 being configured to prevent joint clockwise rotation of second segment 152 and third segment 154. The clockwise rotation may be manually effected by manually rotating first segment 150 from the outside of catheter body 104, or automatically effected by using an external motor (not shown) to rotate first segment 150.
As work element 158 is clockwise rotated, it slides on, and pushes against, internal surface 138, thereby coming into mechanical contact (that is to say, indirect contact mediated by membrane 134) with adjacent regions of the target lesion, causing a compression of lesion material in the adjacent regions (as schematically depicted in
According to some embodiments, step IV may include an anti-clockwise rotation of first segment 150. First segment 150 anti-clockwise rotation is translated into work element 158, second segment 152, and third segment 154 anti-clockwise rotation. A combination of clockwise and anti-clockwise rotations may improve the smoothing of the lesion on the inner walls of the target blood vessel.
When the target blood vessel includes sharp bends near the region of the lesion, rotating third segment 154 may force curved tip 182 into the blood vessel walls (e.g. the walls surrounding the target region). By rotating clockwise first segment 150, third segment 154 rotation is avoided and curved tip 182 is kept away from the blood vessel walls.
According to some embodiments, wherein guidewire 102 is mounted through the chuck, guidewire 102 controllable rotation may be induced by controllably rotating the chuck. According to some embodiments, the chuck may be controllably rotated using a motor. In some such embodiments, the speed of the rotation is controllable. In some such embodiments, the speed of the rotation may be controllably modified during work element 158 rotation.
According to some embodiments, a proximal portion (not numbered in the Figures) of first segment 150 includes a crank mechanism (e.g. a portion of first segment 150 which radially projects relative to the rest of first segment 150, as known in the art), thereby allowing manually rotating first segment 150 and work element 158. According to some embodiments, guidewire 102 may both be mounted through a chuck and include a crank mechanism.
According to some embodiments, step IV may include effecting reciprocating motion (that is to say, back-and-forth proximal and distal motion) of first segment 150. First segment 150 reciprocating motion translates into work element 158 reciprocating motion (as schematically depicted in
The reciprocating motion may be manually effected by manually alternatingly pushing and pulling first segment 150 from the outside of catheter body 104, or automatically effected by using an external motor (not shown) to alternatingly push and pull first segment 150.
According to some embodiments, balloon 108 is a drug-eluting balloon, and may be configured to release a drug, which coats external surface 136, when inflated to the nominal pressure or to a pressure above the nominal pressure, for example, in step II. The drug may also be released from a particular region of membrane 134 even when the pressure within balloon 108 is lower than the nominal pressure, but membrane 134 surface tension in the particular region is high, for example, due to a force exerted on the particular region by convex surface 210 during work element 158 rotation in step IV.
In a step V, work element 158 is switched back to the guiding configuration by controllably releasing first segment 150, for example, by unlocking the chuck in embodiments wherein guidewire 102 is mounted therethrough. Balloon 108 is deflated by pumping out the fluid therein via inflation port 122.
In a step VI, guidewire 102 and catheter body 104 may be pulled out of the subject's body by proximally pulling first segment 150 from the outside of catheter body 104. First segment 150 proximal pull may be translated via first disc 192 and/or third disc 196 via first bearing 140 and/or second bearing 144, respectively, to balloon 108 and catheter body 104 distal pull. If necessary, third segment 154 (anti-clockwise) rotation may be induced by anti-clockwise rotating guidewire 102, as described hereinabove.
According to some embodiments, guidewire 102 and catheter body 104 may be pulled out of the body by proximally pulling tube 110 from outside the subject's body. Tube 110 proximal pull is translated via second bearing 144 and second disc 194 to second segment 152 proximal push at second segment distal end 168, which then translates into a proximal push of first segment 150 and a proximal pull of third segment 154.
According to some embodiments, following step V and prior to step VI, guidewire 102 may be used to guide balloon 108 to another stenosed region and steps II to V may be repeated.
Work element 158 back-and-forth motion results in the smoothing (compression) against vessel inner wall 320 of lesion material in regions of lesion 310, which come into mechanical contact with outer face 240 (due to work element 158 reciprocating motion).
Another exemplary embodiment of a catheter system, as described herein, is schematically depicted in
According to this embodiment, work element 458 includes a lesion-smoothing member in the form of a curved wire 460. Curved wire 460 includes a curved wire proximal end 476, which is connected to first segment 150 at first segment distal end 164, and a curved wire distal end 478, which is connected to second segment 152 at second segment proximal end 166. That is, guidewire 402 is essentially similar to guidewire 102 except for including work element 458 in place of work element 158.
Curved wire 460 radially projects from longitudinal axis B, and, according to some embodiments, is convex (as depicted in
Guidewire 402 may be brought to the work configuration from the guiding configuration by distally pushing first segment 150, thereby exerting on curved wire 460 a distal force at curved wire proximal end 476. Since second segment distal end 168 is fixed, by varying the distal force, a curvature of curved wire 460 may be controllably varied, thereby varying a height of curved wire top 484. As used herein, the height of curved wire top 484 may refer to the distance from curved wire top 484 to longitudinal axis B. When no external forces are acting on curved wire 460, guidewire 402 is in the guiding configuration.
Catheter system 400 may be used to release stenosis in a target blood vessel in essentially the same way as catheter system 100 (and as described hereinabove). To bring guidewire 402 from the guiding configuration to the work configuration, in a step such as step III (i.e. when catheter system 400 is inserted into a subject's body, such that balloon 108 and work element 458 are in a target blood vessel at a region of stenosis, and balloon 108 is inflated), first segment 150 distal push is translated via work element 458 and second segment 152 to a distal push on second bearing 144, which in turn distally pulls on balloon 108. Since balloon 108 is inflated, balloon 108 is prevented from movement by surrounding blood vessel walls and lesions thereon, and, in particular, from distal movement (i.e. movement up the target blood vessel), and, consequently, so is second bearing 144. Due to curved wire 460 being curved and convex, curved wire 460 may be more readily bent than first segment 150 and second segment 152, and the distal push on first segment 150 results in guidewire 402 switching to the work configuration and the height of curved wire top 484 being increased. According to some embodiments, curved wire 460 is made of a more resiliently flexible material than first segment 150 and second segment 152.
According to some embodiments, catheter system 400 admits only the guiding configuration. In such embodiments, the height of curved wire top 484 may be comparable to the height of same in the work configuration in embodiments, which also admit the work configuration. The above-described method for stenosis release may still be used with step III omitted, the switching back from the work configuration to the guiding configuration in a step, such as step V, omitted, and with the guiding configuration being used also for the compression of the target lesion, i.e. in a step such as step IV.
Making reference again to catheter system 100, according to some embodiments, work element 158 does not include first arm 220 and second arm 230, and convex surface 210 is connected to first segment distal end 164 and second segment proximal end 166 at surface proximal end 234 and surface distal end 238, respectively. In such embodiments, convex surface 210 is resiliently flexible, increasing the convexity thereof, and thereby the radial projection thereof, when a distal force is applied at surface proximal end 234 (and when second segment proximal end 166 is substantially fixed, such as when balloon 108 is anchored), essentially as described above with respect to curved wire 460.
Another exemplary embodiment of a catheter system, as described herein, is schematically depicted in
Work element 558 includes a lesion-smoothing member in the form of curved wire 460 and a mechanical spring 570. That is to say, work element 558 is essentially similar to work element 458 except for further including mechanical spring 570, with curved wire top 484 having substantially the same height, as the height thereof in the guiding configuration of catheter system 400. Mechanical spring 570 extends along longitudinal axis B (not visible in
Mechanical spring 570 provides extra stiffness, beyond that provided by curved wire 460, between first segment distal end 164 and second segment proximal end 166. According to some embodiments, the provision of extra stiffness may help in preventing curved wire 460 from being undesirably deformed when switching from the guiding configuration to the work configuration. In particular, when switching from the guiding configuration to the work configuration, mechanical spring 570 may help prevent curved wire proximal end 476 and curved wire distal end 478 from being displaced from longitudinal axis B, or from being too closely pushed toward one another such that curved wire 460 assumes a horseshoe shape.
According to some embodiments, the work element does not include a convex-shaped lesion-smoothing member.
Work element 658 includes a lesion-smoothing member 710 in the form of a wire, a first arm 720 in the form of a wire, and a second arm 730 in the form of a wire. First arm 720 extends from first segment distal end 164 to a proximal end (not numbered) of lesion-smoothing member 710. Second arm 730 extends from a distal end (not numbered) of lesion-smoothing member 710 to second segment proximal end 166. In the guiding configuration, work element 658 is straight or substantially straight (as depicted in
Guidewire 602 includes two pairs of notches. A first notch pair 680 includes a first notch 680a and a second notch 680b. A second notch pair 690 includes a third notch 690a and a fourth notch 690b. First notch 680a and second notch 680b each consists of a groove into an upper portion (not numbered) of guidewire 602. First notch 690a and second notch 690b each consists of a groove into a lower portion (not numbered) of guidewire 602. The terms “upper” and “lower”, as used with respect to
First notch 680a is located at a joining region 762 of first segment 150 and first arm 720. Second notch 680b is located at a joining region 768 of second arm 730 and second segment 152. First notch 690a is located at a joining region 764 of first arm 720 and lesion-smoothing member 710. Second notch 690b is located at a joining region 766 of lesion-smoothing member 710 and second arm 730.
A catheter system including guidewire 602, in particular, a catheter system similar to catheter system 400 except for including guidewire 602 in place of guidewire 402, will be operated essentially similarly to catheter system 400. To switch from the guiding configuration to the work configuration, first segment 150 is distally pushed, when the balloon of the catheter system is anchored within an intraluminal passage and inflated. The distal push forces the walls of each notch, respectively, towards one another. As a result, due to second notch pair 680 being located on the upper portion of guidewire 602, and due to second notch pair 690 being located on the lower portion of guidewire 602, wall-smoothing element 710 is lifted relative to longitudinal axis B.
Another exemplary embodiment of a catheter system 800 is schematically depicted in
To switch from the guiding configuration to the work configuration, first segment 150 is distally pushed, essentially as described above in the description of catheter system 400. To switch from the working configuration to the guiding configuration, first segment 150 is released, and, according to some embodiments, proximally pulled, essentially as described above in the description of catheter system 400.
It is noted that in operation, e.g. when balloon 108 is inflated and anchored inside a target blood vessel, for every full revolution (rotation) of first segment 150, the vessel inner walls are “swept” twice: once by first curved wire 860a, and once by second curved wire 860b.
Also contemplated are embodiments of a catheter system (not depicted in the Figures) including three or more curved wires, such as a curved wire 460, which may be symmetrically disposed relative to a longitudinal axis of the catheter system, such as longitudinal axis B (e.g. in a catheter system including three symmetrically positioned curved wires, the angle between each adjacent pair of curved wires will equal 120°).
Similarly, also contemplated are embodiments of a catheter system (not depicted in the Figures) including two or more work elements, such as work element 158, which are symmetrically disposed relative to a longitudinal axis of the catheter system (such as longitudinal axis B). According to some such embodiments, wherein the work element includes a convex surface, such as convex surface 210, in the guiding configuration, the plurality of work elements define a substantially closed ellipsoidal surface. According to some such embodiments, wherein the work element includes a convex surface, such as convex surface 210, in the work configuration too the plurality of work elements define a substantially closed ellipsoidal surface. In such embodiments, in the guiding configuration, the outer face of each convex surface is partially covered by the inner face of a respective one of the two convex surfaces adjacent thereto (e.g. the convex surface located clockwise thereto).
According to some embodiments, the work element is an elliptical, ellipsoidal, or rounded body, which may be rigid or resiliently flexible.
As used herein, “proximal segment” with respect to a guidewire, such as any one of guidewires 102, 402, 502, 602, and 802, may be used interchangeably with “first segment” (e.g. first segment 150). “Distal segment” with respect to a guidewire, such as any one of guidewires 102, 402, 502, 602, and 802 may be used to refer to the totality of “second segment” and “third segment” (e.g. second segment 152 and third segment 154 make up the distal segment of guidewire 102). “Non-exposed segment” with respect to a guidewire, such as any one of guidewires 102, 402, 502, 602, and 802 may be used interchangeably with “second segment” (e.g. second segment 152). “Exposed segment” with respect to a guidewire, such as any one of guidewires 102, 402, 502, 602, and 802 may be used interchangeably with “third segment” (e.g. third segment 154).
As used herein, “flexible” and “resiliently flexible” with respect to a guidewire, such as any one of guidewires 102, 402, 502, 602, and 802, and components thereof (e.g. convex surface 210 of guidewire 102 and curved wire 460 of guidewire 402) may be used interchangeably.
According to some embodiments, there is provided a catheter system for intraluminal passages, comprising:
wherein said work element comprises an elongated, convex member projecting radially from a longitudinal axis of said inflatable balloon and mechanically associated on a first convex member end with said first segment and on a second convex member end with said second segment; and
wherein said work element is configured to allow for controllable rotation about said longitudinal axis, when said balloon is inflated with a fluid and is inside an intraluminal passage, such that the convex member rotates along the inner surface of said inflatable balloon and simultaneously pushes against said inner surface.
Although certain aspects of the invention have been exemplified in the context of treating blockages in blood vessels, it will be readily appreciated by a person skilled in the art that these same aspects may also be of relevance in treating blockages in intraluminal passages other than blood vessels, such as ureteral passages.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. No feature described in the context of an embodiment is to be considered an essential feature of that embodiment, unless explicitly specified as such.
Although steps of methods according to some embodiments may be described in a specific sequence, methods of the invention may comprise some or all of the described steps carried out in a different order. A method of the invention may comprise all of the steps described or only a few of the described steps. No particular step in a disclosed method is to be considered an essential step of that method, unless explicitly specified as such.
Although the invention is described in conjunction with specific embodiments thereof, it is evident that numerous alternatives, modifications and variations that are apparent to those skilled in the art may exist. Accordingly, the invention embraces all such alternatives, modifications and variations that fall within the scope of the appended claims. It is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth herein. Other embodiments may be practiced, and an embodiment may be carried out in various ways.
The phraseology and terminology employed herein are for descriptive purpose and should not be regarded as limiting. Citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the invention.
Section headings are used herein to ease understanding of the specification and should not be construed as necessarily limiting.
| Number | Date | Country | |
|---|---|---|---|
| 20170151421 A1 | Jun 2017 | US |
