Guidewire with elastically articulatable tip
A guidewire for vascular access has an elastically articulatable tip configured to minimize risk of vessel wall damage during initial insertion of the guidewire into the vasculature of a patient. The guidewire may have a local flexible portion in a tip segment of the guidewire and/or a core thereof.
1 . A guidewire for transluminal routing of artifacts in a blood vessel, comprising:
a guidewire body comprising an elastic core member extending along at least most of the length of the guidewire body, the guidewire body comprising a guidewire proximal segment, a tip segment and a guidewire intermediate segment extending between the guidewire proximal segment and the tip segment;
wherein resistance to bending of the guidewire intermediate segment along at least most of the length thereof is smaller than resistance to bending along at least most of the length of the guidewire proximal segment;
wherein the tip segment includes a local flexing portion having a resistance to bending smaller than (1) the resistance to bending of the guidewire intermediate segment, (2) of a front portion of the tip segment extending to distally from the local flexing portion, and (3) of a rear portion of the tip segment extending proximally from the local flexing portion, thereby affecting localized elastic articulatability of the front portion of the tip segment relative to the rear portion of the tip segment and/or to the guidewire intermediate segment;
wherein the elastic core member has a diameter that reduces from a first diameter proximal to a narrowing to a second diameter smaller than the first diameter distal to the narrowing; and
wherein the elastic core member comprises a widening proximal to the local flexing portion, wherein the widening increases the elastic core member diameter from a third diameter proximal to the widening to a fourth diameter greater than the third diameter distal to the widening.
2 . The guidewire according to claim 1 , wherein the local flexing portion is configured to facilitate and cause elastically recoverable buckling of the rear portion of the tip segment upon longitudinal compression of the guidewire body against a blood vessel wall, when the front portion of the tip segment is forcefully articulated relative to the rear portion of the tip segment.
3 . The guidewire according to claim 1 , wherein the tip segment is 20 mm or less in total length.
4 . The guidewire according to claim 1 , wherein the tip segment is 10 mm or less in total length.
5 . The guidewire according to claim 1 , wherein the tip segment is 5 mm or less in total length.
6 . The guidewire according to claim 1 , wherein the local flexing portion includes at least one of a slit, a joint, an indentation, a coiled segment, or any combination thereof.
7 . The guidewire according to claim 1 , wherein the third core member diameter is equal to or smaller than the second core member diameter and/or the fourth core member diameter is equal to the first core member diameter.
8 . The guidewire according to claim 1 , wherein the elastic core member is embedded in a matrix of flexible material between the narrowing and the widening of the elastic core member, such that an overall diameter of the guidewire body along at least most of the length of the guidewire intermediate segment is equal to the first diameter.
9 . The guidewire according to claim 1 , wherein the elastic core member is covered with a cylindrical coiled member between the narrowing and the widening of the elastic core member, such that an overall diameter of the guidewire body along at least most of the length of the guidewire intermediate segment is equal to the first diameter.
10 . The guidewire according to claim 9 , wherein the cylindrical coiled member is formed of a spring or elastic metal alloy and is fixated to the elastic core member at or adjacent to the narrowing or at or adjacent to the widening.
11 . The guidewire according to claim 1 , wherein the core member incorporates the flexing portion along the tip segment.
12 . The guidewire according to claim 1 , wherein the local flexing portion has a length along the guidewire body that is equal to or smaller than 5 mm.
13 . The guidewire according to claim 1 , wherein the local flexing portion has a length along the guidewire body of equal to or smaller than 3 mm.
14 . The guidewire according to claim 1 , wherein the local flexing portion is equal to or smaller than 1 mm.
15 . The guidewire according to claim 1 , wherein the elastic core member is formed of a selectively heat-treated shape memory alloy.
16 . The guidewire according to claim 15 , wherein a portion of the elastic core member is heat-treated by exposure to a temperature of about 500° C. or less during a period of about 1 minute or less.
17 . The guidewire according to claim 16 , wherein the exposure precedes fixation of a distal end of a coiled member to the elastic core member distally to the local flexing portion.
18 . The guidewire according to claim 1 , wherein the resistance to bending of the local flexing portion increases when an angle formed between the front portion of the tip segment and the rear portion of the tip segment reduces.
19 . The guidewire according to claim 18 , wherein a minimally allowed articulation angle between the front portion of the tip segment and the rear portion of the tip segment is between 150° and 90°.
20 . The guidewire according to claim 19 , wherein the minimally allowed articulation angle is between 135° and 95°.
21 . The guidewire according to claim 1 , wherein a total length of the local flexing portion is 0.5 mm or less.
22 . The guidewire according to claim 1 , wherein a diameter of the local flexing portion is equal to a diameter of the rear portion of the tip segment and/or to the guidewire intermediate segment.
23 . The guidewire according to claim 1 , wherein a center of the local flexing portion is 5 mm or less from a distal end of the guidewire body.
24 . The guidewire according to claim 1 , wherein a center of the local flexing portion is 1 mm or less from a distal end of the guidewire body.
25 . A kit comprising:
a guidewire comprising a guidewire body having a guidewire proximal segment, a tip segment and a guidewire intermediate segment extending between the guidewire proximal segment and the tip segment; and
a needle comprising a beveled opening distally adjacent to a distal needle tip;
wherein resistance to bending of the guidewire intermediate segment along at least most of the length thereof is smaller than resistance to bending along at least most of the length of the guidewire proximal segment;
wherein the tip segment includes a local flexing portion having resistance to bending smaller than (1) the resistance to bending of the guidewire intermediate segment, (2) of a front portion of the tip segment extending to distally from the local flexing portion, and (3) of a rear portion of the tip segment extending proximally from the local flexing portion, thereby affecting localized elastic articulatability of the front portion of the tip segment relative to the rear portion of the tip segment and/or to the guidewire intermediate segment;
wherein the beveled opening has a length configured such that when the front portion of the tip segment is pushed against a blood vessel wall, the front portion is configured to articulate about the local flexing portion upon axial protrusion from the beveled opening.
26 . The kit according to claim 25 , wherein the beveled opening is equal to or greater by up to 2 mm than the front portion in length.
27 . The kit according to claim 25 , wherein the beveled opening is equal to or smaller by up to 2 mm than the front portion in length.
28 . A guidewire for transluminal routing of artifacts in a blood vessel, comprising:
a guidewire body comprising a guidewire proximal segment, a tip segment and a guidewire intermediate segment extending between the guidewire proximal segment and the tip segment;
wherein resistance to bending of the guidewire intermediate segment along at least most of the length thereof is smaller than resistance to bending along at least most of the length of the guidewire proximal segment;
wherein the tip segment includes a local flexing portion having resistance to bending smaller than the resistance to bending of (1) the guidewire intermediate segment, (2) of a front portion of the tip segment extending to distally from the local flexing portion, and (3) of a rear portion of the tip segment extending proximally from the local flexing portion, thereby affecting localized elastic articulatability of the front portion of the tip segment relative to the rear portion of the tip segment and/or to the guidewire intermediate segment;
wherein the resistance to bending of the local flexing portion is smaller than resistance to penetration of a wall of the blood vessel with the tip segment when the front portion of the tip segment and the rear portion of the tip segment are aligned, and/or
wherein the resistance to bending of the local flexing portion is greater than a resistance to buckling of the rear portion of the tip segment when the front and the rear portions of the tip segment form a minimally allowed articulation angle therebetween.
29 . The guidewire according to claim 28 , wherein the local flexing portion is about 3 mm or less in length and distant about 5 mm or less from a distal end of the guidewire body.
30 . The guidewire according to claim 28 , wherein the resistance to bending of the local flexing portion is smaller than resistance to penetration of a wall of the blood vessel with the tip segment when the front portion of the tip segment and the rear portion of the tip segment are aligned.
31 . The guidewire according to claim 29 , wherein the resistance to bending of the local flexing portion is greater than a resistance to buckling of the rear portion of the tip segment when the front and the rear portions of the tip segment form a minimally allowed articulation angle therebetween.