Catheter shaft and associated devices, systems, and methods

Abstract

Systems, devices, and methods for detaching an implantable device from a delivery system are disclosed herein. One aspect of the present technology, for example, is directed toward an elongated shaft having an inner surface that defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of a distal portion. In some embodiments the distal portion includes an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure. The first portion can have a first stiffness and the second portion can have a second stiffness less than the first stiffness. The distal portion can further include an outer polymer structure disposed around the inner polymer structure and a coil wound around the inner polymer structure and disposed within the outer polymer structure.

I/We claim: 
     
         1 . A catheter, comprising:
 an elongated shaft having a proximal portion and a distal portion, wherein an inner surface of the elongated shaft defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of the distal portion;   wherein the distal portion includes—
 an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure, wherein the first portion has a first stiffness and the second portion has a second stiffness less than the first stiffness; 
 an outer polymer structure disposed around the inner polymer structure; and 
 a coil wound around the inner polymer structure and disposed within the outer polymer structure. 
   
     
     
         2 . The catheter of  claim 1  wherein a distal terminus of the second portion coincides with the opening at the distal terminus of the shaft. 
     
     
         3 . The catheter of  claim 1  wherein a distal terminus of the second portion is distal to a distal terminus of the coil. 
     
     
         4 . The catheter of  claim 1  wherein a distal terminus of the second portion is proximal to a distal terminus of the coil. 
     
     
         5 . The catheter of  claim 1  wherein the portion of the coil within the distal portion includes a first region and a second region distal to the first region, wherein the first region has a tighter pitch than the second region. 
     
     
         6 . The catheter of  claim 1  wherein the portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions each have a tighter pitch than the second region. 
     
     
         7 . The catheter of  claim 1  wherein the portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions each have a wider pitch than the second region. 
     
     
         8 . The catheter of  claim 1  wherein the inner polymer structure includes a first layer and a second layer surrounding the first layer, and wherein an inner surface of the first layer defines a portion of the lumen. 
     
     
         9 . The catheter of  claim 1  wherein the inner polymer structure includes a first layer and a second layer surrounded by the first layer, and wherein the first and second portions together comprise the first layer. 
     
     
         10 . The catheter of  claim 1 , further including a radiopaque marker positioned around the inner polymer structure and/or outer polymer structure. 
     
     
         11 . The catheter of  claim 1  wherein a thickness of each of the inner polymer structure and the outer polymer structure are constant along the length of the distal portion. 
     
     
         12 . The catheter of  claim 1  wherein a thickness of at least one of the inner polymer structure and the outer polymer structure tapers along the length of the distal portion. 
     
     
         13 . A catheter, comprising:
 an elongated shaft having a proximal portion and a distal portion, wherein an inner surface of the elongated shaft defines a lumen that extends distally from the proximal portion to an opening at a distal terminus of the distal portion;   wherein the distal portion includes—
 an inner polymer structure having a first portion and a second portion positioned distal of the first portion along the length of the inner polymer structure, wherein the first portion is made of a first material and the second portion is made of a second material different than the first material; 
 a radiopaque band positioned around a portion of the inner polymer structure; 
 an outer polymer structure disposed around the inner polymer structure and the radiopaque band; and 
 a coil wrapped around the inner polymer structure and disposed within the outer polymer structure, wherein the coil has a pitch that varies along the length of the coil. 
   
     
     
         14 . The catheter of  claim 13  wherein the portion of the coil within the distal portion includes a first region and a second region distal to the first region, wherein the first region has a tighter pitch than the second region. 
     
     
         15 . The catheter of  claim 13  wherein the portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions have a tighter pitch than the second region. 
     
     
         16 . The catheter of  claim 13  wherein the portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions have a wider pitch than the second region. 
     
     
         17 . The catheter of  claim 13  wherein the portion of the coil within the distal portion includes a first region, a second region distal to the first region, and a third region distal to the second region, wherein the first and third regions each have a wider pitch than the second region. 
     
     
         18 . The catheter of  claim 13  wherein a stiffness of the second portion is less than a stiffness of the first portion. 
     
     
         19 . The catheter of  claim 13  wherein the inner polymer structure includes a first layer and a second layer surrounding the first layer, and wherein an inner surface of the second layer defines a portion of the lumen. 
     
     
         20 . The catheter of  claim 13  wherein the inner polymer structure includes a first layer and a second layer surrounded by the first layer, and wherein the first and second portions together comprise the first layer.