Abstract: Vascular blood flow modulation is disclosed using metallic compliance-enhancement devices that contain a sealed volume of fluid. The device includes a first elongated inflatable nitinol balloon and a second elongated inflatable nitinol balloon, each having an outer sealed terminus and an inner open fluid port, and a nitinol connector tube that fluidly couples the balloons and has a diameter smaller than the inflated diameters of the balloons. The first balloon is positioned within an arterial vessel and the second balloon is positioned within a venous vessel, with the connector tube spanning between the vessels. During systole, arterial pressure compresses the first balloon to drive fluid through the connector tube into the second balloon, thereby expanding the second balloon and increasing venous blood flow. Cyclic systolic and diastolic pressure variations cause fluid to shuttle between the balloons, producing a compliance-enhancing effect.

Abstract: A stent implant includes a first stent segment having a non-circular axial cross-sectional shape in a relaxed configuration thereof, second and third stent segments on opposite sides of the first stent segment, the second and third stent segments having a circular relaxed axial cross-sectional shape, a fluid-tight covering disposed on at least one of an outer diameter or an inner diameter of the first, second, and third stent segments, and a blood flow egress channel in fluid communication with a space on the outer diameter of the first stent segment, the blood flow egress channel configured to permit blood flow to pass axially out of the space through the blood flow egress channel.

Abstract: Systems and methods are described for modulating blood flow through a blood vessel. The systems may include one or more implantable devices including a stent frame positionable within the blood vessel, the stent frame having a substantially oval cross-sectional shape, and a valve defining an inflow end and an outflow end. The inflow end may be coupled to the stent frame and the outflow end defining an aperture and the valve may include at least one leaflet at the outflow end. The at least one leaflet may be positionable to overlay at least a portion of the aperture and configured to move in a radial direction that is perpendicular to a central axis of the stent frame.

Abstract: An implant delivery system includes an elongate sheath having an inner diameter at a distal end thereof, a nose cone shaft dimensioned for advancement within the elongate sheath, and a collapsible nose cone associated with a distal end of the nose cone shaft and positionable at least partially beyond the distal end of the elongate sheath, the collapsible nose cone being transitionable between an expanded state having a first maximum diameter and a compressed state having a second maximum diameter that is less than the inner diameter of the elongate sheath.

Abstract: An intravascular compliance-enhancing spring implant device includes a fully-cylindrical tubular frame defining a longitudinal axis and a non-circular cross-sectional shape having a major axis diameter and a minor axis diameter that is less than the major axis diameter, first and second longitudinal tissue-contact rails associated with first and second major-axis ends, respectively, of the tubular frame and adapted to press against an inner diameter of a target blood vessel, and first and second lateral connecting strut arrays associated with minor-axis sides of the tubular frame, the first and second lateral connecting strut arrays spanning between the first and second tissue-contact rails on diametrically opposite sides of a lumen of the tubular frame and adapted to be compressed along a major-axis dimension of the tubular frame in a manner as to reduce a distance between the first and second tissue-contact rails, storing spring energy in the lateral connecting strut arrays.

Abstract: Methods of reshaping blood vessels for improving compliance and increasing blood flow are disclosed. One preferred method includes deploying a tubular stent frame within a blood vessel. The stent frame preferably has a non-circular cross-section with a major-axis and a minor-axis. At least one tissue anchor is provided along a wall portion on the minor-axis. The tissue anchor is embedded into a wall of the blood vessel and the wall of the blood vessel is drawn into contact with the minor-axis wall portion. Preferably, tissue anchors are provided along opposing minor-axes of the stent frame for reshaping the blood vessel into a substantially oval cross-section. When exposed to high blood pressure, the stent frame expands to a more circular shape for allowing more blood to pass therethrough. Under low pressure, the stent frame returns to a non-circular cross-section to aid with the pumping of blood.

Abstract: Devices and methods for locking a deliverable (e.g., a prosthetic implant, a tool, etc.) relative to a delivery apparatus are disclosed. As an example, a method of delivering a prosthetic implant can comprise inserting a delivery apparatus into a patient's vasculature, wherein the delivery apparatus comprises a first shaft, a second shaft, and an inner component disposed within a lumen of the first shaft; moving the inner component and the first shaft relative to each other; and locking the inner component and the first shaft relative to each other by applying an axial force to a shoulder of the first shaft with the second shaft.

Abstract: A method of managing blood flow involves advancing a delivery system to a blood vessel segment and deploying a first stent from the first delivery system at a first position in the blood vessel segment, the first stent having a non-circular cross-sectional shape defining a major-axis diameter and a minor-axis diameter that is less than the major-axis diameter. A second stent is deployed from the delivery system at a second position spaced from the first position by a first axial gap, the second stent having the non-circular cross-sectional shape and being physically coupled to the first stent by first and second coupling arms positioned on opposite major-axis circumferential portions of the first and second stents, respectively. Systolic pressure is reduced through circularization of the first and second stents and diastolic pressure is increased through shape-memory return of the first and second stents to non-circular shapes.

Abstract: A flow restrictor for a blood vessel can include a frame positionable within a blood vessel, and a leaflet or flap comprising an inflow end and an outflow end. The inflow end of the leaflet or flap can be configured to move (optionally using a control element) in response to a first increase in a blood pressure within the blood vessel, and in response to the blood pressure being within a first blood pressure range. The flow restrictor can be further configured to be a bi-modal flow restrictor, wherein the leaflet or flap can be configured to collapse or prolapse in response to the blood pressure being within a second blood pressure range. In some cases, the bi-modal flow restrictor can include an inner valve configured to move with respect to the frame in response to the blood pressure being within the second blood pressure range.

Abstract: A method of coupling a stent to a blood vessel involves deploying a stent in a target blood vessel segment, the stent having a non-circular biased shape, forcing the stent to a more-circular shape compared to the non-circular biased shape using a tie coupled across an inner diameter of the stent in a tensioned state, maintaining the tie in the tensioned state for a period of time sufficient to allow tissue overgrowth to couple the stent to a wall of the target blood vessel segment, and de-tensioning the tie to allow the stent to reshape the blood vessel segment to a non-circular shape.

Abstract: An implant device includes a unitary stent frame including a first axial end segment having a circular cross-sectional shape, a second axial end segment having a circular cross-sectional shape, and a medial segment disposed between the first axial end segment and the second axial end segment, the medial segment having an oval cross-sectional shape. A fluid-tight covering can be disposed on minor-axis sidewall portions of the medial segment of the stent frame.

Abstract: An implant for adding compliance to a blood vessel includes a first elongate rail shaped to contact an inner wall of a blood vessel and a second elongate rail shaped to contact an opposing inner wall of the blood vessel. Connectors extend between the first and second rails for providing a separation therebetween and maintaining the rails at locations on opposing sides of the lumen after implantation. The connectors push the rails outwardly for biasing the blood vessel toward a substantially oval shape. The connectors are preferably flexible for allowing the blood vessel to change shape during use for adding compliance to the blood vessel. The elongate rails are preferably curved or hemi-spherical for conforming to the shape of the inner wall of the blood vessel.

Abstract: A stent comprises a network of elastically deformable struts having a biased cross-sectional shape and forming a first end portion having a first central diameter in a major dimension and a second central diameter in a minor dimension, wherein the first central diameter is greater than the second central diameter, a second end portion having the first central diameter in the major dimension and the second central diameter in the minor dimension, and a middle portion situated between the first end portion and the second end portion, the middle portion having a third central diameter in the major dimension and the second central diameter in the minor dimension, the third central diameter being less than the first central diameter.