Medical device suitable for location in a body lumen
Inventors
Heraty, Kevin • Mullins, Liam • Gilson, Paul • BURKE, MARTIN
Assignees
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Publication Number
US-9539120-B2
Publication Date
2017-01-10
Expiration Date
Abstract
A stent (1) for deployment in a blood vessel which is movable between an unloaded straight cylindrical state and a loaded curved state. The stent (1) is bendable between a first loaded configuration when the blood vessel is in the unloaded state, and a second loaded configuration when the blood vessel is in the loaded state. The stent (1) has an unloaded configuration which is intermediate the first loaded configuration and the second loaded configuration. Because of the unloaded configuration of the stent (1), the degrees of deformation which the stent (1) undergoes are minimized leading to minimized strains, increased fatigue life, and reduced risk of fracture.
Core Innovation
The invention relates to a stent and a method of stenting a body lumen in which a stent is deployed and expanded to a fully expanded deployed configuration that is ready for use. In the fully expanded deployed configuration, the stent can have a first loaded configuration, a second loaded configuration, and an unloaded configuration intermediate the first and second loaded configurations, in which at least part of the longitudinal axis of the stent is curved to a first curved state.
After expanding the stent to the fully expanded deployed configuration, subsequent steps deform the stent to the first loaded configuration when the body lumen bends to an unloaded state thereof. The method further deforms the stent from the first loaded configuration through the unloaded configuration to the second loaded configuration when the body lumen bends to a loaded state thereof that is more curved than the unloaded state, with the first loaded configuration less curved and the second loaded configuration more curved than the first curved state.
The disclosed embodiments include unloaded configuration geometries in which the stent longitudinal axis is curved in a two-dimensional plane or curved in three-dimensional space. In additional embodiments, the unloaded configuration corresponds to a helical configuration that is induced to change between unloaded and loaded states, and the disclosure further describes transitional deformation to mitigate deformation and strain during vessel bending, with alignment using visualization means and deployment in tortuous sites.
The disclosed concepts also include embodiments in which deployment forces the vessel into a helical configuration to induce swirling blood flow, and the disclosure states that this reduces thrombosis and platelet adhesion and helps inhibit intimal hyperplasia. The stent and its deployment are also described with multi-bend and helical three-dimensional space curvature geometries between unloaded and more-loaded states.
Claims Coverage
Independent claim clm-00001 defines a method of stenting with a fully expanded deployed configuration having an intermediate unloaded curved longitudinal-axis state and two loaded configurations whose longitudinal-axis curvature is respectively less and more curved than the unloaded state, with deformation carried out as the body lumen transitions between unloaded and more-curved loaded bending states. Dependent claims specify geometric dimensionality, helical geometry constraints, force-induced helical configuration, and deformation by twisting between loaded configurations.
Intermediate unloaded configuration with first curved longitudinal-axis state
In the fully expanded deployed configuration, the stent has an unloaded configuration intermediate the first and second loaded configurations, where the unloaded configuration is one in which at least part of the longitudinal axis of the stent is curved to a first curved state.
Curvature transition between first loaded, unloaded, and second loaded configurations
After expanding to the fully expanded deployed configuration, deforming the stent to the first loaded configuration when the body lumen bends to an unloaded state thereof, and deforming the stent from the first loaded configuration through the unloaded configuration to the second loaded configuration when the body lumen bends to a loaded state thereof which is more curved than said unloaded state; wherein the first loaded configuration has the at least part of the longitudinal axis less curved than in the first curved state of the unloaded configuration and the second loaded configuration has the at least part of the longitudinal axis more curved than in the first curved state.
Two-dimensional plane curvature in the unloaded configuration
In the unloaded configuration, at least a portion of the stent’s longitudinal axis is curved within a two-dimensional plane.
Three-dimensional space curvature in the unloaded configuration
In the unloaded configuration, at least part of the stent’s longitudinal axis is curved in three-dimensional space.
Helical amplitude-to-diameter ratio comparison between unloaded and second loaded configurations
The ratio of the amplitude of a helical longitudinal axis of the stent to the stent diameter is greater in a second loaded configuration than in an unloaded configuration.
Force to cause the body lumen to adopt a helical configuration
The method further exerts a force on a body lumen using a stent to cause the body lumen to adopt a helical configuration.
Twisting deformation between first and second loaded configurations
The deforming step comprises twisting a stent between a first loaded configuration and a second loaded configuration.
Overall, the claim coverage centers on a deformation pathway where a stent with an intermediate unloaded curved longitudinal-axis state is deformed into a less-curved first loaded configuration and then into a more-curved second loaded configuration as the body lumen transitions from an unloaded bending state to a more curved loaded bending state. Dependent claims further restrict the unloaded-state geometry to two-dimensional plane curvature or three-dimensional space curvature, and in certain embodiments define helical geometry relationships, force-induced helical configuration, and twisting as the deformation mechanism.
Stated Advantages
Minimizing deformation/strain during vessel bending.
Reducing thrombosis.
Reducing platelet adhesion.
Helping inhibit intimal hyperplasia.
Documented Applications
Stenting a body lumen, including deployment in tortuous sites with alignment using visualization means.
Use of helical configurations to induce swirling blood flow in the deployed vessel.
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