Capacitive intravascular pressure-sensing devices and associated systems and methods

Abstract

Intravascular devices, systems, and methods are disclosed. In some embodiments, the intravascular devices are guide wires that include a capacitive pressure-sensing component disposed at a distal portion of the guide wire. Methods of making such intravascular devices, including various manufacturing and assembling techniques, are disclosed. Systems associated with such intravascular devices and methods of using such devices and systems are also disclosed.

What is claimed is: 
     
         1 . An intravascular pressure-sensing guide wire, comprising:
 a first elongate flexible element configured to be positioned within a blood vessel of a patient, the first elongate flexible element comprising a proximal portion and a distal portion;   a capacitive pressure sensor positioned at the distal portion of the first elongate flexible element, the capacitive pressure sensor comprising:
 a cavity; and 
 a flexible membrane positioned over the cavity, 
 wherein the flexible membrane comprises a conductive member such that the conductive member is displaced by changes in ambient pressure within the blood vessel, relative to a pressure in the cavity; and 
   an electronic component positioned at the distal portion of the first elongate flexible element, wherein the electronic component is in electrical communication with the conductive member.   
     
     
         2 . The guide wire of  claim 1 , wherein the electronic component comprises an integrated circuit. 
     
     
         3 . The guide wire of  claim 1 , wherein the electronic component comprises an application-specific integrated circuit (ASIC). 
     
     
         4 . The guide wire of  claim 1 , further comprising a mounting structure positioned at the distal portion of the first elongate flexible element, wherein the electronic component is coupled to the mounting structure. 
     
     
         5 . The guide wire of  claim 1 , further comprising a housing positioned at the distal portion of the first elongate flexible element, wherein the housing comprises the capacitive pressure sensor and the electronic component. 
     
     
         6 . The guide wire of  claim 5 , wherein the housing further comprises an opening in a sidewall of the housing and in communication with the cavity. 
     
     
         7 . The guide wire of  claim 1 , wherein the first elongate flexible element comprises a first conductive material, and wherein the electronic component is in electrical communication with the first elongate flexible element. 
     
     
         8 . The guide wire of  claim 7 , further comprising:
 a first conductive band, wherein a section of the proximal portion of the first elongate flexible element is electrically coupled to the first conductive band such that the electronic component is in electrical communication with the first conductive band.   
     
     
         9 . The guide wire of  claim 8 , further comprising:
 a second elongate flexible element positioned around the first elongate flexible element, the second elongate flexible element being formed of a second conductive material, wherein the electronic component is in electrical communication with the second elongate flexible element.   
     
     
         10 . The guide wire of  claim 9 , wherein a section of a proximal portion of the second elongate flexible element defines a second conductive band. 
     
     
         11 . The guide wire of  claim 10 , further comprising an insulating member positioned between the first and second conductive bands, the insulating member being positioned around the first elongate flexible element. 
     
     
         12 . The guide wire of  claim 10 , wherein an outer diameter of the second elongate flexible element is 0.018″ or less. 
     
     
         13 . The guide wire of  claim 10 , wherein an outer diameter of the second elongate flexible element is 0.014″ or less. 
     
     
         14 . An intravascular pressure-sensing system, the system comprising:
 a pressure-sensing guide wire configured to be positioned within a blood vessel of a patient, the pressure-sensing guide wire comprising:
 an elongate flexible element comprising a proximal portion and a distal portion; 
 a capacitive pressure sensor positioned at the distal portion of the elongate flexible element, the capacitive pressure sensor comprising:
 a cavity; and 
 a flexible membrane positioned over the cavity, 
 wherein the flexible membrane comprises a conductive member such that the conductive member is displaced by changes in ambient pressure within the blood vessel, relative to a pressure in the cavity; and 
 an electronic component positioned at the distal portion of the elongate flexible element, wherein the electronic component is in electrical communication with the conductive member; and 
 
   a processing system configured to process data obtained by the pressure-sensing guidewire.   
     
     
         15 . The system of  claim 14 , further comprising:
 an interface configured to communicatively couple the pressure-sensing guidewire and the processing system.