Blood-flow tubing
An artificial or modified natural blood flow tubing has a helical-flow inducer to induce helical flow in such fashion as to eliminate or reduce turbulence. One inducer is a tubular stent of expansible mesh having a helical vane.
1. An intravascular stent comprising a metal tubular mesh member, the tubular mesh member having an internal helical formation to induce spiral-flow therethrough, the internal helical formation having a helix angle between 5 and 16 degrees relative to a longitudinal axis of the stent.
2. The stent according to claim 1 , wherein the tubular mesh member is expansible and is inserted by catheterization in collapsed form and which becomes expanded on release from the catheter, the internal helical formation being attached to an interior portion of the tubular mesh member.
3. The stent according to claim 2 , wherein the tubular mesh member comprises crisscrossed wires extending helically around the periphery of the stent, and the internal helical formation comprises a helical vane member attached to such wires.
4. The intravascular stent according to claim 1 , wherein the helix angle of the internal helical formation is adjustable.
5. The intravascular stent according to claim 1 , wherein the internal helical formation comprises:
a rigid support coaxially mounted within the tubular mesh member; and
a spiral flow inducer vane surrounding and extending from the rigid support.
6. The stent according to claim 1 , wherein the internal helical formation comprises:
a rigid support rod coaxially mounted in the tubular member;
a flexible sleeve within the tubular member and surrounding the support rod;
a flexible helical vane mounted to the sleeve; and
wherein the sleeve is axially contractible relative to the support rod to vary an angle of the vane relative to the support rod.
7. The intravascular stent according to claim 1 , wherein the helix angle is about 16 degrees relative to the longitudinal axis of the tubular member.
8. An intravascular stent comprising:
an expansible tubular mesh member having a collapsed form to be inserted into a vein and an expanded form to be retained within the vein;
the mesh member having at least one vane stationarilly attached to an interior thereof and extending helically to induce spiral flow of blood, said at least one vane having a helix angle of between 5 and 16 degrees relative to a longitudinal axis of the mesh member.
9. The stent according to claim 8 , wherein the mesh member comprises a plurality of wires that extend helically and cross each other to form junctions.