Unfused catheter body feature and methods of manufacture
View Patent ↗The disclosure is directed to tubular bodies for catheters. An inner tubular catheter body has an inner layer, a braided portion over the inner layer and an outer layer. The outer layer is fused to the braided portion for a selected length or lengths of the inner tubular body and is unfused for a selected length or lengths to achieve the desired combination of stiffness and flexibility.
1. A medical catheter comprising a flexible shaft having a proximal portion and a distal end portion, said shaft having a tubular body including:
an inner layer that defines a lumen;
a braided portion that extends over at least a portion of said inner layer, the braided portion comprising a plurality of turn components defining a selected pic count;
an outer layer that extends over the braided portion, the outer layer having a proximal end and a distal end;
a fused region of the tubular body, the fused region being a first selected length of the tubular body, the first selected length including a first length of each of the inner layer, the braided portion and the outer layer, said tubular body fused region first selected length having said first length of the outer layer fused to the first length of the braided portion;
an unfused region of the tubular body, the unfused region having a defined radius and a defined length that is a second selected length of the tubular body, the unfused region second selected length including a second length of each of the inner layer, the braided portion and the outer layer, said tubular body unfused region second selected length inner layer, braided portion and outer layer are unfused to each other and are unfused to any and all other members along the second selected length;
said turn components of the braided portion at the fused region are fixed and non-slidable with respect to each other due to their fusion to the outer layer, while said turn components of the braided portion at the unfused region slide with respect to each other, whereby the fused region is stiffer than the unfused region, the unfused region has a greater flexibility than the fused region, and the unfused region is thereby of greater bendability than the fused region for following a vasculature path to enhance trackability;
said fused region and said defined length unfused region being coaxial with each other; and
wherein said outer layer at the fused region and at the unfused region have the same composition, being made of the same polymer material and being of the same durometer hardness.
2. The catheter of claim 1 wherein said outer layer is formed from a material selected from the group consisting of polyamides, polyimides, nylons, polyethylenes, PVDF, polyesterether block amides, polyurethanes and combinations thereof.
3. The catheter of claim 1 wherein said outer layer is formed from a polyesterether block amide.
4. The catheter of claim 1 wherein the material of said outer layer has a Shore durometer hardness of not greater than about 72D.
5. The catheter of claim 1 wherein the material of said outer layer has a Shore durometer hardness of from about 25D to about 60D.
6. The catheter of claim 1 wherein the material of said outer layer has a Shore durometer hardness of from about 35D to about 55D.
7. The catheter of claim 1 wherein said inner layer is formed from a material selected from the group consisting of polytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene (EPTFE) and high density polyethylene (HDPE).
8. The catheter of claim 1 wherein the selected pic count of said braided portion is from about 25 to about 140 pics/inch.
9. The catheter of claim 1 wherein the selected pic count of said braided portion is from about 60 to about 120 pics/inch.
10. The catheter of claim 1 further comprising a balloon fixed to said tubular body along at least a portion of the length of the unfused region and external of the unfused region.
11. The catheter of claim 10 wherein the unfused region extends longitudinally beyond the balloon.
12. The catheter of claim 1 wherein said unfused region is at the distal end portion of said tubular body, and the remainder of said outer layer is said fused region.
13. The catheter of claim 1 wherein said outer layer is formed by extrusion of a material over the braided portion and said inner layer.
14. The catheter of claim 1 wherein said outer layer has a Shore durometer hardness of less than about 72D.
15. The catheter of claim 1 wherein said outer layer has a Shore durometer hardness of from about 25D to about 55D.
16. A balloon catheter, comprising:
a balloon member having a proximal leg and a distal leg;
a flexible shaft having a proximal portion and distal end portion, the shaft defining a lumen;
a tubular body within said lumen of the flexible shaft, said tubular body including a distal end portion, an inner layer that defines a lumen, a braided portion that extends over at least a portion of said inner layer, the braided portion comprising a plurality of turn components defining a selected pic count, an outer layer that extends over the braided portion, the outer layer having a proximal and distal end;
a fused region of the tubular body, the fused region being a first selected length of the tubular body, the first selected length including a first length of each of the inner layer, the braided portion and the outer layer, said tubular body fused region first selected length having said first length of the outer layer fused to the first length of the braided portion;
an unfused region of the tubular body, the unfused region having a defined radius and a defined length that is a second selected length of the tubular body, the unfused region second selected length including a second length of each of the inner layer, the braided portion and the outer layer, said tubular body unfused region second selected length inner layer, braided portion and outer layer being unfused to each other and are unfused to any and all other members along the second selected length;
said turn components of the braided portion at the fused region are fixed and non-slidable with respect to each other due to their fusion to the outer layer, while said turn components of the braided portion at the unfused region slide with respect to each other, whereby the fused region is stiffer than the unfused region, the unfused region has a greater flexibility than the fused region, and the unfused region is thereby of greater bendability than the fused region for following a vasculature path to enhance trackability;
said fused region and said defined length unfused region being coaxial with each other;
said outer layer at the fused region and at the unfused region having the same composition, being composed of the same polymer material and having the same durometer hardness along its length;
said proximal leg of the balloon member is secured to said distal end portion of the flexible shaft, and said distal leg of the balloon member is secured to said distal end portion of the tubular body; and
said unfused length is positioned at a location radially inward of at least a portion of said balloon between the proximal leg and the distal leg of the balloon.
17. The balloon catheter of claim 16 wherein said unfused length extends substantially the entire length of the balloon.
18. The balloon catheter of claim 16 wherein said unfused length comprises one or more unfused lengths and extends between approximately the proximal end of the proximal leg of the balloon member to the proximal end of the distal leg of the balloon member.
19. The balloon catheter of claim 16 wherein said unfused length extends proximally of the proximal end of the distal leg of the balloon member.