Stents having protruding drug-delivery features and associated systems and methods
Inventors
Fulkerson, John • Rizk, Isa • Mustapha, Jihad Ali • Jimenez, Jr., Teodoro S.
Assignees
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Publication Number
US-10258487-B2
Publication Date
2019-04-16
Expiration Date
Abstract
Expandable elements having drug-delivery features and associated systems and methods are disclosed herein. In one embodiment, a drug-eluting stent includes a radially expandable cylindrical frame having a plurality of struts. The frame is transformable between a low-profile delivery state and an expanded deployed state. A plurality of drug-delivery features are carried by one of the struts and configured to deliver a drug to a treatment site within the patient or piercing through the tissue wall to break the constricting of the vessel wall inwardly. When the frame is in the expanded state within a body lumen of the patient, the drug-delivery features extend radially outwardly away from the strut and are configured to engage and, in some arrangements, pass through a wall of the body lumen.
Core Innovation
The invention relates to an expandable element for treating a human patient that includes a radially expandable cylindrical frame having struts, a proximal end, a distal end, and a lumen providing a fluid pathway along a longitudinal axis of the frame. The frame is transformable between a deployed state having a deployed diameter and a constrained low-profile delivery state having a smaller delivery diameter for delivery to a treatment site within a body lumen. While in the constrained low-profile delivery state, a plurality of protruding features carried by and integrally formed with the struts do not extend radially outwardly away from the frame.
As the frame is released or deployed from the constrained low-profile delivery state at the treatment site within the body lumen, the frame transforms to the deployed state and the deployed diameter, and the protruding features, moving with the frame, are released to engage tissue of the body lumen. Each protruding feature forms a terminal end that extends radially outwardly away from the frame positioned entirely distal to a first portion extending substantially parallel to the longitudinal axis of the frame, so that the terminal end extends into and engages the tissue to enable delivery to deeper layers. The invention is directed to integrating radially outward drug-delivery features into a stent or expandable structure in a way that maintains a low-profile during delivery while enabling tissue engagement after deployment.
The invention further addresses problems with conventional drug-eluting stents and drug-eluting expandable devices by proposing integrally formed radially outward engagement and penetration features that increase contact area and address dosing uniformity and tissue penetration limitations. It supports delivery of a drug from the protruding features, including multiple drug types, and can optionally include drug reservoirs and reservoir-controlled release. The disclosed expandable structures are collapsible from the deployed state to the delivery state to be retracted within a catheter and withdrawn from the body lumen of the patient.
Claims Coverage
The provided material includes two independent claims. Both claims cover an expandable cylindrical frame transformable between a constrained low-profile delivery state and a deployed state, with integrally formed protruding features that remain non-radially-extending during delivery and deploy to engage body-lumen tissue after deployment; one claim further specifies an axial longitudinal withdrawal member and integrally formed metal or metal alloy construction with self-expansion behavior.
Expandable element with integrally formed radially outward protruding features released upon deployment
A radially expandable cylindrical frame with struts and a lumen providing a fluid pathway along a longitudinal axis, transformable between a constrained low-profile delivery state and a deployed state, wherein a plurality of protruding features carried by and integrally formed with the struts do not extend radially outwardly away from the frame in the constrained low-profile delivery state, and in the deployed state the protruding features are released to engage tissue such that a first portion extends substantially parallel to the longitudinal axis and a second portion forms a terminal end that extends radially outwardly away from the frame and is positioned entirely distal to the first portion; wherein the frame is collapsible from the deployed state to the delivery state for retraction within a catheter and withdrawal from the body lumen.
Expandable stent with integrally formed longitudinal protruding features that reorient to tissue-engaging terminal ends and a longitudinal withdrawal member
An expandable stent including a radially expandable cylindrical frame with struts and a lumen providing a fluid pathway along a longitudinal axis, transformable between a constrained low-profile delivery state and a deployed state; a plurality of protruding features carried by and integrally formed with the struts that are substantially parallel to the longitudinal axis in the delivery state and, in the deployed state, have a first portion extending from the frame substantially parallel to the longitudinal axis and a second portion forming a terminal end that extends perpendicularly away from the longitudinal axis to engage tissue and is positioned entirely distal to the first portion; a longitudinal member coupled to the frame and configured to withdraw the frame in the deployed state from the body lumen; wherein the frame and the protruding features are integrally formed of a metal or metal alloy; wherein the frame and the protruding features are configured to be held in the delivery state by radial compression and self-expands to the deployed diameter when released; and wherein the frame is collapsible from the deployed state to the delivery state to be retracted within a catheter and withdrawn from the body lumen.
Across the independent claims, the core coverage centers on an expandable cylindrical frame that is delivered in a constrained low-profile delivery state while integrally formed protruding features remain radially non-extending, then deploy to create defined axial portions and tissue-engaging terminal ends that extend radially outward or perpendicularly away from the frame; one independent claim additionally requires a longitudinal withdrawal member and integrally formed metal or metal alloy construction with radial-compression holding and self-expansion behavior.
Stated Advantages
Improve dosing uniformity relative to conventional drug-eluting stents and drug-eluting expandable devices.
Provide tissue penetration by enabling the protruding features to engage and extend into deeper layers of the vessel wall tissue.
Increase contact area with the vessel wall tissue while maintaining low-profile delivery and allowing blood flow.
Enable delivery of drugs to deeper layers using integrally formed radially outward drug-delivery features.
Documented Applications
Treating a human patient using an expandable element or an expandable stent delivered to a treatment site within a body lumen.
Drug delivery within a body lumen using protruding features, including multiple drug types and optional reservoir-controlled release.
Demonstrated evaluation in human cadaver vessel histology to compare tissue engagement and penetration among protruding feature geometries without vessel perforation.
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