Conformable balloon devices and methods
The present disclosure is directed toward a semi-compliant to non-compliant, conformable balloon useful in medical applications. Conformable balloons of the present disclosure exhibit a low or insignificant straightening force when in a curved configuration and at inflation pressures greater than 4 atm. Balloons of the present disclosure are constructed of material that can compress along an inner length when the balloon is in a curved configuration. In further embodiments, balloons of the present disclosure can be constructed of material that sufficiently elongates along an outer arc when the balloon is in a curved configuration. As a result, medical balloons, in accordance with the present disclosure, when inflated in a curved configuration, exhibit kink-free configurations and do not cause a significant degree of vessel straightening.
1. A medical balloon having a working length and comprising
a balloon wall defining a chamber, wherein at least a portion of the balloon wall comprises a material that is longitudinally compressed;
wherein the medical balloon is configured to be inflated to a pressure of at least 4 atm and is semi-compliant to non-compliant when inflated to a pressure of at least 4 atm;
wherein the longitudinally compressed material allows the balloon wall to be bent to an orientation imparting at least 20% total strain to the balloon wall, and when the medical balloon is inflated to a pressure of at least 4 atm and not subjected to a bending force, the medical balloon will assume an essentially straight configuration, and further when the medical balloon is inflated to a pressure of at least 4 atm and is subjected to a bending force of 20% total strain, the medical balloon, along a portion of the working length, defines an inner arc and an outer arc and a portion of balloon wall extending along the inner arc undergoes at least 5% compressive strain.
2. The medical balloon of claim 1 , wherein the balloon wall is configured to remain kink-free when inflated in the curved configuration.
3. The medical balloon of claim 1 , wherein the portion of the balloon wall extending along the inner arc has a length of at least 5 mm.
4. The medical balloon of claim 1 , wherein the balloon wall material comprises a porous microstructure.
5. The medical balloon of claim 4 , wherein the porous microstructure is highly fibrillated.
6. The medical balloon of claim 4 , wherein the porous microstructure is expanded polytetrafluoroethylene.
7. The medical balloon of claim 1 , wherein the portion of balloon wall extending along the inner arc undergoes at least 10% compressive strain.
8. The medical balloon of claim 1 ,
wherein the longitudinally compressed material allows the balloon wall to be bent to an orientation imparting at least 25% total strain to the balloon wall; and
wherein when the medical balloon is inflated to a pressure of at least 4 atm and is subjected to a bending force of 25% total strain, the portion of balloon wall extending along the inner arc undergoes at least 10% compressive strain.
9. The medical balloon of claim 1 , wherein the working length of the balloon lengthens less than 10% during inflation to at least an angioplasty pressure.
10. The medical balloon of claim 1 , wherein the balloon wall material is configured to remain kink-free when a ratio of a balloon diameter within the working length to a bend radius is at least 1:3.
11. The medical balloon of claim 1 , further comprising a compliant bladder.
12. The medical balloon of claim 1 , wherein the medical balloon is inflatable to a pressure greater than 8 atm.
13. The medical balloon of claim 1 , wherein the balloon wall material comprises a circumferential stiffness greater than 200 gf/mm/mm.
14. The medical balloon of claim 1 , wherein the balloon wall material comprises a circumferential stiffness and a longitudinal stiffness and wherein the circumferential stiffness is at least 5 times greater than the longitudinal stiffness.
15. The medical balloon of claim 14 , wherein the medical balloon has an inflated diameter of 4 mm and a longitudinal stiffness less than 30 gf/mm/mm.
16. The medical balloon of claim 14 , wherein the medical balloon has an inflated diameter of 8 mm and a longitudinal stiffness less than 70 gf/mm/mm.
17. The medical balloon of claim 1 , wherein the balloon wall material comprises a helically wrapped film at an angle greater than 80 degrees relative to the longitudinal axis and wherein the helically wrapped film comprises a balance ratio of at least 10:1.
18. The medical balloon of claim 1 , further comprising an endovascular medical device disposed about the balloon.
19. The medical balloon of claim 1 , wherein the balloon wall comprises a material having a porous microstructure, wherein at least a portion of the porous microstructure comprises a plurality of voids defined by the porous microstructure.
20. The medical balloon of claim 1 , further comprising a therapeutic agent attached to the balloon.
21. A medical balloon having a length along a longitudinal axis comprising
a polymeric balloon wall material, wherein at least a portion of the balloon wall comprises a material that is longitudinally compressed;
wherein the medical balloon is configured to be inflated to a pressure of at least 4 atm and is semi-compliant to non-compliant when inflated to a pressure of at least 4 atm;
wherein when the medical balloon is inflated to a pressure of at least 4 atm and not subjected to a bending force, the medical balloon will assume an essentially straight configuration;
wherein the balloon wall material comprises a circumferential stiffness and a longitudinal stiffness; and
wherein the longitudinally compressed material allows the medical balloon to readily bend when inflated to at least 4 atm and subjected to a bending force of 20% total strain, imparting the medical balloon with a circumferential stiffness at least 5 times greater than the longitudinal stiffness.
22. The balloon of claim 21 , wherein the circumferential stiffness is at least 8 times greater than the longitudinal stiffness.
23. The medical balloon of claim 21 , wherein the balloon wall material remains kink-free when inflated in a curved configuration.
24. The medical balloon of claim 21 , wherein the balloon wall material comprises a material with a porous microstructure.
25. The medical balloon of claim 24 , wherein the porous microstructure is highly fibrillated.
26. The medical balloon of claim 24 , wherein the porous microstructure is expanded polytetrafluoroethylene.
27. The medical balloon of claim 21 , wherein a working length of the balloon lengthens less than 10% during inflation to at least an angioplasty pressure.
28. The medical balloon of claim 21 , wherein the balloon wall material is configured to remain kink free when a ratio of a balloon diameter within a working length to a bend radius is at least 1:3.
29. The medical balloon of claim 21 , further comprising a compliant bladder.
30. The medical balloon of claim 21 , wherein the medical balloon is inflatable to a pressure greater than 8 atm.
31. The medical balloon of claim 21 , wherein the balloon wall material comprises a circumferential stiffness greater than 200 gf/mm/mm.
32. The medical balloon of claim 21 , wherein the medical balloon has an inflated diameter of 8 mm and a longitudinal stiffness is less than 70 gf/mm/mm.
33. The medical balloon of claim 21 , wherein the medical balloon has an inflated diameter of 4 mm and a longitudinal stiffness is less than 30 gf/mm/mm.
34. The medical balloon of claim 21 , wherein the balloon wall material comprises a helically wrapped film at an angle greater than 80 degrees relative to the longitudinal axis and wherein the helically wrapped film comprises a balance ratio of at least 10:1.
35. The balloon of claim 21 , wherein the circumferential stiffness is at least 10 times greater than the longitudinal stiffness.