Infusion wire having fixed core wire

Claim 1

A flexible elongated medical infusion wire having a proximal infusion wire portion and a distal infusion wire portion enclosing an infusion lumen and extending between an infusion wire proximal end and an infusion wire distal end, the infusion wire adapted for introduction through a selected path in a patient's body to a site in a blood vessel or body cavity and for infusing infusate fluids into the blood vessel or body cavity, the infusion wire further comprising: an inner sheath formed at least in part of a wire reinforced, polyimide tube providing resistance to collapse of the inner sheath through the proximal infusion wire portion in use of the infusion wire, the inner sheath having an inner sheath lumen formed therein, said inner sheath extending from said infusion wire proximal end and distally through said proximal infusion wire portion to an intermediate junction of said proximal infusion wire portion with said distal infusion wire portion; a helically wound, distal wire coil extending between a distal wire coil proximal end and a distal wire coil distal end and having a distal coil lumen formed therein, said distal wire coil extending distally from said intermediate junction through said distal infusion wire portion to said infusion wire distal end, said wire coil having a proximal wire coil section and a distal wire coil section, said proximal wire coil section closely wound at a close coil winding pitch and said distal wire coil section space wound at a varying coil pitch to provide a distally increasing helical spacing between adjacent coil turns; an outer sheath extending between said proximal infusion wire end and said distal infusion wire end having a sheath side wall enclosing an outer sheath lumen receiving said inner sheath in a proximal outer sheath portion thereof and receiving said wire coil in a distal outer sheath portion thereof such that said inner sheath lumen and said coil lumen are substantially co-axially aligned at said intermediate junction and define said infusion lumen; a plurality of infusion ports formed through said outer sheath side wall that are spaced apart from one another and extend along said distal outer sheath portion for a defined infusion length thereof for allowing transmission of infusate fluids from said infusion lumen and through the helical spacing of said distal wire coil section and through said infusion ports to the exterior of said distal outer sheath portion; an elongated stiffening core wire extending between a proximal core wire end and a distal core wire end comprising a proximal core wire portion positioned within said inner sheath lumen and extending therein from said proximal infusion wire end to said intermediate junction and a distal core wire portion positioned within said distal coil lumen and extending therein from said intermediate junction to said distal infusion wire end, said proximal core wire portion formed with a proximal core wire portion diameter smaller than the diameter of said inner sheath lumen thereby defining a proximal infusion lumen having a proximal infusion lumen cross-section area in said proximal infusion wire portion, said distal core wire portion further formed of a proximal core wire section and a distal core wire sections, said proximal core wire section formed with a proximal core wire section diameter smaller than the diameter of said distal coil lumen, and said distal core wire section formed with a distal core wire section diameter smaller than said proximal core wire section diameter, thereby providing a distal infusion lumen having a distally increasing distal infusion lumen cross-section area; and means engaging said proximal core wire end and the proximal ends of said outer sheath and said inner tubular sheath for allowing the infusion of the infusate fluid into the proximal infusion lumen at the infusion wire proximal end and transmission of the infusate fluid distally through said proximal infusion lumen to the distal infusion lumen, whereby the distally increasing cross-section area of the distal infusion lumen and the distally increasing helical spacing provide emission of the infusate fluid out of the plurality of infusion ports to the exterior of said distal outer sheath portion in a relatively uniform flow rate along the defined infusion length.