Abstract: A stent (1) comprising a tubular frame (2) comprising a first end (3) and a second end and a longitudinal axis (4) therebetween. The frame (2) comprises a plurality of struts (9) defining a generally cylindrical portion comprising a longitudinally extending helical fin (11) protruding radially inwardly and having a helix angle. The angle, relative to the longitudinal axis (4), of at least some of the struts (9) in the helical fin (11) is substantially aligned with the helix angle of the helical fin (11).

Abstract: A conduit arrangement (1) comprises distal and proximal ends (2,3) and two tubular lumens (10,11). Each tubular lumen (10,11) comprises a longitudinal axis extending between the distal and proximal ends (2,3) and independently permits fluid communication between the distal and proximal ends (2,3). The interior of each of the two tubular lumens is made from a biocompatible material. At least a portion of at least one tubular lumen (10, 11) is capable of imparting helical flow on fluid passing through said portion of the tubular lumen (10,11). The helical flow is spiral laminar flow.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: A stent (1) comprising a tubular frame (2) comprising a first end (3) and a second end and a longitudinal axis (4) therebetween. The frame (2) comprises a plurality of struts (9) defining a generally cylindrical portion comprising a longitudinally extending helical fin (11) protruding radially inwardly and having a helix angle. The angle, relative to the longitudinal axis (4), of at least some of the struts (9) in the helical fin (11) is substantially aligned with the helix angle of the helical fin (11).

Abstract: A conduit arrangement (1) comprises distal and proximal ends (2,3) and two tubular lumens (10,11). Each tubular lumen (10,11) comprises a longitudinal axis extending between the distal and proximal ends (2,3) and independently permits fluid communication between the distal and proximal ends (2,3). The interior of each of the two tubular lumens is made from a biocompatible material. At least a portion of at least one tubular lumen (10, 11) is capable of imparting helical flow on fluid passing through said portion of the tubular lumen (10,11). The helical flow is spiral laminar flow.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: A tubular conduit comprising: a tubular portion made from a flexible material. There is an external helical formation extending around the exterior of, and parallel to the axis of, the tubular portion and defining a first region of the tubular portion. The external helical formation is for supporting the tubular portion. There is also an internal helical formation, protruding inwardly of the interior of the tubular portion and extending parallel to the axis of the tubular portion and defining a second region of the tubular portion. The internal helical formation is for imparting helical flow on fluid passing through the tubular portion. The first region does not extend throughout the second region.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: A vascular access graft comprises an elongate conduit having proximal and distal ends. At least a portion of the elongate conduit has a self-sealing property such that the portion remains impermeable after puncturing by a dialysis needle. The vascular access graft also comprises a helical fin projecting inwardly from the inner surface of the elongate conduit and extending parallel to the axis of the elongate conduit.

Abstract: A vascular access graft (1) comprises an elongate conduit (2) having proximal and distal ends (3, 4). At least a portion of the elongate conduit (2) has a self-sealing property such that the portion remains impermeable after puncturing by a dialysis needle. The vascular access graft (1) also comprises a helical fin (6) projecting inwardly from the inner surface (5) of the elongate conduit (2) and extending parallel to the axis of the elongate conduit (2).

Abstract: A tubular conduit comprising: a tubular portion made from a flexible material. There is an external helical formation extending around the exterior of, and parallel to the axis of, the tubular portion and defining a first region of the tubular portion. The external helical formation is for supporting the tubular portion. There is also an internal helical formation, protruding inwardly of the interior of the tubular portion and extending parallel to the axis of the tubular portion and defining a second region of the tubular portion. The internal helical formation is for imparting helical flow on fluid passing through the tubular portion. The first region does not extend throughout the second region.

Abstract: An internal formation for a conduit. The formation has a longitudinally extending member adapted to extend along an inside surface of at least a portion of the length of the conduit. The longitudinally extending member has an asymmetric profile in a direction transverse of the longitudinal axis of the member.

Abstract: A vascular access graft (1) comprises an elongate conduit (2) having proximal and distal ends (3, 4). At least a portion of the elongate conduit (2) has a self-sealing property such that the portion remains impermeable after puncturing by a dialysis needle. The vascular access graft (1) also comprises a helical fin (6) projecting inwardly from the inner surface (5) of the elongate conduit (2) and extending parallel to the axis of the elongate conduit (2).

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such a fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.

Abstract: There is disclosed an insert (2) for a conduit (4) adapted to effect helical flow in the conduit (4) comprising a longitudinally extending member having a helical formation.

Abstract: There is disclosed a method for introducing a helical formation (11) into a flexible tubular material (12). The material (12) is supported together with a surrounding helical former (13) so as to deform the material (12) to have a helical indentation (11) corresponding to the shape of the former (13). The material (12) is then set in that configuration and the former (13) is removed.

Abstract: A tubular graft (1) comprises an elongate conduit (2) having distal and proximal ends (3, 4). The tubular graft (1) also comprises a helical fin (10) projecting inwardly from the inner surface of the elongate conduit (2) and extending parallel to the axis of the elongate conduit (2). The helical fin (10) extends from the distal end (3) of the elongate conduit (2) to a point (11) short of the proximal end (4) of the elongate conduit (2).

Abstract: A helical formation within a conduit and a method of determining the helix angle of the helical formation are disclosed. The method includes specifying the internal dimensions of the conduit and an intended fluid mass flow through the conduit. The helix angle is determined from the pressure drop and the turbulent kinetic energy for a conduit having the specified internal dimensions and intended fluid mass flow.

Abstract: A Method of Determining the Helix Angle of a Helical Formation for a Conduit. A method of determining the helix angle of a helical formation (4) within a conduit (1). The method includes specifying the internal dimensions of the conduit (1) and an intended fluid mass flow through the conduit (1). The helix angle is determined from the pressure drop and the turbulent kinetic energy for a conduit (1) having the specified internal dimensions and intended fluid mass flow.