Infusion catheter with uniform distribution of fluids

Claim 1

An infusion catheter comprising an elongated catheter body having a proximal end and a distal end and having an infusion section at its distal end for delivery of therapeutic fluid to bodily passages, said infusion section having a proximal portion and a distal portion and comprising: a first infusion catheter tube having a wall delimiting a first lumen, said first tube wall having a multiplicity of first ports therethrough; and a second infusion catheter tube disposed within and concentric with said first lumen, said second tube having a wall delimiting a second lumen, said second tube wall being uniformly spaced apart from said first tube wall to provide an annular passageway within said first lumen, the radial depth of said annular passageway being sufficient to permit fluid flow therewithin, said second tube wall having a multiplicity of second ports therethrough; wherein each of said first ports provides fluid communication between said annular passageway and the exterior of said catheter and each of said second ports provides fluid communication between said second lumen and said annular passageway such that said therapeutic fluid can flow from said second lumen through said second ports into said annular passageway, flow within said annular passageway, and flow from said annular passageway through said first ports to said catheter exterior; and the said first ports and said second ports are positioned relative to one another such that the average fluid flow distance in said annular passageway between said second ports and said first ports is smaller in said infusion section distal portion than in said infusion section proximal portion to provide a substantially uniform average flow rate of said therapeutic fluid flowing from each of said first ports to said catheter exterior along the length of said infusion section.