Flexible tubular spring structure, and scoring balloon catheter equipped therewith
A resiliently expandable elongate tubular spring structure, e.g., corresponding to a metal mesh type structure, mountable or mounted to a scoring balloon catheter includes multiple ring structures that are longitudinally separated from each other along portions of a balloon working region, and which are resiliently radially expandable in response to outwardly directed balloon expansion forces. Pairwise adjacent ring structures are structurally coupled and separated from each other by a scoring link, e.g., a single scoring link, configured as a traumatic structure with respect to vascular tissue, e.g., by way of having a square, trapezoidal, or raised blade tissue scoring/cutting profile. Each ring structure includes a pair of radially resiliently radially expandable annular springs, longitudinally separated from each other by a plurality of spacing elements, e.g., wire links, and which are atraumatic or substantially atraumatic structures relative to the scoring link with respect to tissue.
1 . A flexible elongate tubular spring structure for a flexible scoring balloon catheter configured for insertion into a vessel within a mammalian cardiovascular system or other fluid or air carrying conduit or duct within a living mammalian body, the scoring balloon catheter comprising an inflatable elongate balloon having a working region spanning a length, an outer surface along its working region, a first internal passage along which a guide wire is insertable, a second internal passage for passage of a pressurized fluid in communication with the interior of the balloon, and a first longitudinal axis centrally aligned with and extending through the first internal passage, wherein the working region of the balloon in a folded, undeployed, or unexpanded state respectively has a folded, undeployed, or unexpanded outer cross sectional area perpendicular to the first longitudinal axis, wherein the working region of the balloon in an expanded or deployed state respectively has an expanded or deployed outer cross sectional area perpendicular to the first longitudinal axis that is greater than the folded outer cross sectional area, the undeployed outer cross sectional area, and the unexpanded cross sectional area, and wherein the tubular spring structure has a distal end, a proximal end, a length therebetween within which a lumen resides, and a second longitudinal axis centrally aligned with its lumen, and wherein the tubular spring structure comprises:
(i) a plurality of annular ring structures, each annular ring structure having an unexpanded length and providing along its length a lumen having a central axis longitudinally extending therethrough and a relaxed cross sectional area perpendicular to the central axis which in the absence of the balloon is less than the folded, undeployed, or unexpanded outer cross sectional area of the balloon's working region, wherein each annular ring structure is configured for circumferential engagement with the outer surface of the balloon such that the central axis of the annular ring structure is longitudinally aligned with a portion of the first longitudinal axis, wherein each annular ring structure is configured for resilient expansion in radial directions perpendicular to the central axis including outward radial expansion away from the central axis in response to radial forces exerted on the annular ring structure by expansion of the balloon, and wherein each annular ring structure of the plurality of annular ring structures comprises each of:
(a) a distal annular spring having a circumference and configured for circumferentially residing around the outer surface of the balloon, wherein the distal annular spring is configured for resilient radial expansion relative to a plane perpendicular to the central axis, and wherein the distal annular spring is configured for exerting an inward circumferential compressive force toward the central axis in response to outward radial expansion of the distal annular spring away from the central axis beyond the relaxed cross sectional area;
(b) a proximal annular spring longitudinally separated from the distal annular spring, the proximal annular spring having a circumference and configured for circumferentially residing around the outer surface of the balloon, wherein the proximal annular spring is configured for resilient radial expansion relative to a plane perpendicular to the central axis, and wherein the proximal annular spring is configured for exerting an inward circumferential compressive force toward the central axis in response to outward radial expansion of the proximal annular spring away from the central axis beyond the relaxed cross sectional area;
and
(c) a set of spacing elements peripherally disposed around the annular ring structure, and further disposed between the distal annular spring of the annular ring structure and the proximal annular spring of the annular ring structure, wherein the set of spacing elements couples the distal annular spring of the annular ring structure to the proximal annular spring of the annular ring structure and maintains a longitudinal separation distance between the distal annular spring of the annular ring structure and the proximal spring of the annular ring structure;
wherein each distinct pair of adjacent annular ring structures of the plurality of annular ring structures is longitudinally organized as a first annular ring structure disposed distal to and separated by the longitudinal spatial gap from a second annular ring structure, wherein the proximal annular spring of the first annular ring structure resides at a distal side of a longitudinal spatial gap that separates the first annular ring structure from the second annular ring structure, and wherein the distal annular spring of the second annular ring structure resides at a proximal side of the longitudinal spatial gap that separates the first annular ring structure from the second annular ring structure; and
(ii) a plurality of scoring links, wherein each scoring link has a length, wherein for each distinct pair of adjacent annular ring structures within the plurality of annular ring structures only a single scoring link extends from the distal annular spring of the first annular ring structure to the proximal annular spring of the second annular ring structure such that the single scoring link structurally couples the distinct pair of adjacent annular ring structures and spans the longitudinal spatial gap that separates the first annular ring structure from the second annular ring structures of the distinct pair of annular ring structures, wherein each scoring link comprises a set of scoring structures along at least portions of its length, wherein each scoring structure is configured as a traumatic element with respect to contact with tissue within the vessel, conduit, or duct, wherein serially successive scoring links along the length of the tubular spring structure are disposed at or indexed across different radial positions relative to each other about a circumference of the second longitudinal axis, and wherein the length of each scoring link is greater than the unexpanded length of each annular ring structure within the adjacent pair of annular ring structures coupled thereby.
2 . The tubular spring structure of claim 1 , wherein each of the distal annular spring and the proximal annular spring has a cross sectional area perpendicular to the central axis which in the absence of the balloon is less than the folded, undeployed, or unexpanded outer cross sectional area of the balloon.
3 . The tubular spring structure of claim 1 , wherein each scoring link has a length greater than 200% of the unexpanded length of a shortest annular ring structure within the pair of adjacent annular ring structures coupled thereby.
4 . The tubular spring structure of claim 1 , wherein for each distinct pair of adjacent annular ring structures, the longitudinal spatial gap between the annular ring structures thereof is at least 0.3 mm when the balloon is fully expanded, and wherein the length of the single scoring link that couples the distinct pair of adjacent annular ring structures is between 5%-30% greater than a combined length of the distinct pair of annular ring structures coupled thereby.
5 . The tubular spring structure of claim 1 , wherein for each distinct pair of adjacent annular ring structures, spacing elements of the distinct pair of adjacent annular ring structures do not span or bridge the longitudinal spatial gap between the distinct pair of adjacent annular ring structures, and wherein a longitudinal extent of each spacing element parallel to the central axis of each annular ring structure of each distinct pair of adjacent annular ring structures is less than 50% of the length of the single scoring link coupling the distinct pair of adjacent annular ring structures parallel to the second longitudinal axis of the tubular spring structure.
6 . The tubular spring structure of claim 1 , wherein each spacing element has a width that is between 50% to 500% of the width of each scoring link and/or a scoring element carried thereby.
7 . The tubular spring structure of claim 1 , wherein for each annular ring structure the set of spacing elements includes a plurality of distinct spacing elements longitudinally aligned with the central axis, and wherein the tubular spring structure has a total of N scoring links and (N+1) annular ring structures.
8 . The tubular spring structure of claim 7 , wherein an angular separation between serially successive scoring links around the second longitudinal axis is (360/Y) degrees, where Y is a number between 3 and 5.
9 . The tubular spring structure of claim 1 , wherein the distal annular spring comprises a plurality of spring members that are coupled together around the circumference of the distal annular spring.
10 . The tubular spring structure of claim 1 , wherein the proximal annular spring comprises a plurality of spring members that are coupled together around the circumference of the proximal annular spring.
11 . The tubular spring structure of claim 9 , wherein each spring member includes a first end segment, a second end segment, and an apex therebetween, and wherein each end segment of each spring member is coupled to one of a spacing element and a scoring link.
12 . The tubular spring structure of claim 10 , wherein each spring member includes a first end segment, a second end segment, and an apex therebetween, and wherein each end segment of each spring member is coupled by a spacing element.
13 . The tubular spring structure of claim 1 , wherein at least one of:
(a) the distal annular spring comprises a plurality of spring members that are coupled together around the circumference of the distal annular spring and the plurality of spring members of the distal annular spring includes spring members that exhibit a v-shaped or c-shaped profile with respect to or along the periphery or circumference of the distal annular spring; and
(b) the proximal annular spring comprises a plurality of spring members that are coupled together around the circumference of the proximal annular spring and the plurality of spring members of the proximal annular spring includes spring members that exhibit a v-shaped or c-shaped profile with respect to or along the periphery or circumference of the proximal annular spring.
14 . The tubular spring structure of claim 1 , wherein the second longitudinal axis adopts a curvilinear or curved shape in response to flexure of the tubular spring structure, and wherein when the tubular spring structure is in a straight configuration such that no curvature exists along the second longitudinal axis, (a) each scoring link is a straight longitudinal structure, or (b) one or more scoring links include or are curved structures corresponding to portions of a spiral or helix.
15 . The tubular spring structure of claim 1 , wherein each scoring structure within the set of scoring structures is elongate and is longitudinally aligned with the second longitudinal axis.
16 . The tubular spring structure of claim 1 , wherein each scoring link has a scoring structure integrally formed thereon, or integrally forms a scoring structure.
17 . The tubular spring structure of claim 1 , wherein each scoring structure has a rectangular, trapezoidal, or raised blade cross-sectional shape perpendicular to the second longitudinal axis.
18 . The tubular spring structure of claim 1 , wherein each spacing element within each annular ring structure of a distinct pair of adjacent annular ring structures is elongate and is longitudinally aligned with the central axis, and each spacing element within each annular ring structure of the distinct pair of adjacent annular ring structures has a length that is at least 40% of the length of the single scoring link that couples the distinct pair of adjacent annular ring structures.
19 . The tubular spring structure of claim 1 , wherein each annular ring structure comprises a metal mesh.
20 . The tubular spring structure of claim 1 , wherein the tubular spring structure is formed of at least one metal or metal alloy.
21 . The tubular spring structure of claim 1 , wherein the tubular spring structure is integrally formed from a metal tube.
22 . The tubular spring structure of claim 1 , wherein at least portions of at least some of the plurality of scoring links of the tubular spring structure and/or one or more other portions of the tubular spring structure carry a therapeutic substance.
23 . A flexible scoring balloon catheter, comprising:
an inflatable elongate balloon having a distal end, a proximal end, and a working region therebetween configured for dilation within a vessel of a mammalian cardiovascular system vessel or other fluid or air carrying conduit or duct within a mammalian body, the balloon having a length along its working region, an outer surface along its working region, an internal passage along which a guide wire is insertable, and a first longitudinal axis centrally aligned with and extending through the internal passage, wherein the working region of the balloon in a folded or undeployed state respectively has a folded or undeployed outer cross sectional area perpendicular to the first longitudinal axis, and wherein the working region of the balloon in an expanded or deployed state respectively has an expanded or deployed outer cross sectional area perpendicular to the first longitudinal axis that is greater than the folded outer cross sectional area and the undeployed outer cross sectional area;
a catheter having a distal portion and a proximal portion, wherein the balloon is mounted on the catheter distal portion, and wherein the catheter comprises an inflation lumen extending therethrough in fluid communication with an interior region of the balloon; and
a flexible elongate tubular spring structure of claim 1 , surrounding portions of the working region of the balloon along the catheter distal portion.
24 . The flexible scoring balloon catheter of claim 23 , further comprising at least one of:
a tether structure configured for tethering or anchoring the tubular spring structure to at least one of a portion of the catheter and a portion of the balloon;
a proximal adhesive bond coupling a proximal end of the tubular spring structure to at least one of a proximal zone of the catheter distal portion and an unexpandable proximal segment of the balloon; and
a distal adhesive bond coupling a distal end of the tubular spring structure to at least one of a distal zone of the catheter distal portion and an unexpandable distal segment of the balloon.
25 . The flexible scoring balloon catheter of claim 24 , wherein the tether structure comprises:
a tubular collar carried by a shaft of the catheter proximal to the balloon; and
at least one elongate tether link coupled to each of the tubular collar and the tubular spring structure.
26 . The flexible scoring balloon catheter of claim 24 , wherein the flexible scoring balloon catheter includes each of the proximal adhesive bond and the distal adhesive bond, wherein the distal adhesive bond is intentionally formed to be weaker than the proximal adhesive bond.
27 . The flexible scoring balloon catheter of claim 23 , wherein the flexible scoring balloon catheter excludes protective elements configured to limit or shield contact between the plurality of scoring links and tissue within the vessel prior to inflation of the balloon from the folded, undeployed, or unexpanded state to the expanded or deployed state.