System and method for measuring cross-sectional areas and pressure gradients in luminal organs

A system for measuring luminal cross-sectional area of blood vessels, heart valves, and other hollow visceral organs, for enabling selection of an appropriately sized stent or other medical device and for avoiding under or over deployment and under or over sizing of the stent or other medical device, comprising:

• a catheter extending from a proximal catheter end to a distal catheter end, said catheter capable of being introduced into a treatment site, said catheter comprising a suction/infusion port near the distal catheter end;
• an impedance wire positioned at least partially within the catheter, said impedance wire configured so that a cross-sectional area of a vessel at the treatment site can be determined using conductance values obtained by the impedance wire, said impedance wire comprising:
• two or more excitation electrodes, and
• two or more detection electrodes positioned between the two or more excitation electrodes, wherein a known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive;
• a solution delivery source for injecting a solution through the catheter, through the suction/infusion port and into the treatment site, the solution delivery source capable of injection of two or more solutions into the treatment site;
• a current source in communication with at least one of the excitation electrodes, the current source operable to supply electrical current to the treatment site;
• and
• a data acquisition and processing system in communication with the detection electrodes, the data acquisition and processing system operable to obtain measurements of two or more conductance values at the treatment site from the impedance wire and further operable and to calculate a cross-sectional area at the treatment site in part based upon the obtained two or more conductance values and a known distance between at least two of the two or more detection electrodes;
• wherein the known distance between at least two of the two or more detection electrodes is between 0.5 mm and 1 mm, inclusive.

An impedance assembly, comprising:

• an elongated body extending from a proximal body end to a distal body end;
• an elongated tube extending from a proximal tube end to a distal tube end, the elongated tube defining a first lumen along the longitudinal axis of the tube, wherein at least part of the elongated body is positioned within the elongated tube;
• a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the body, both located near the distal body end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode configured for connection to a data acquisition system near the proximal body end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode configured for connection to the data acquisition system;
• a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the body, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode configured for connection to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode configured for connection to the data acquisition system;
• and
• a first suction/infusion port located near the distal tube end, wherein said first suction/infusion port is in communication with said first lumen;
• the impedance assembly configured so that the first detection impedance electrode and the second detection impedance electrode can obtain one or more conductance values within an electric field generated by the first excitation impedance electrode and the second excitation impedance electrode, and wherein a cross-sectional area of a vessel can be calculated based in part upon the one or more obtained conductance values and a known distance between said first detection impedance electrode and said second detection impedance electrode;
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.

A system for measuring a cross-sectional area of a targeted treatment site, comprising:

• an impedance catheter extending from a proximal catheter end to a distal catheter end, said catheter further comprising a pair of detection impedance electrodes positioned between a pair of excitation impedance electrodes and a suction/infusion port near the distal catheter end;
• a solution delivery source for injecting a solution through the catheter, through the suction/infusion port and into the treatment site;
• a current source;
• and
• a data acquisition and processing system that receives conductance data from the catheter;
• the impedance catheter configured so that the pair of detection impedance electrodes can obtain one or more conductance values within an electric field generated by the pair of excitation impedance electrodes, and wherein a cross-sectional area of the treatment site can be calculated based in part upon the one or more obtained conductance values and a known distance between the pair of detection impedance electrodes;
• wherein the known distance between the pair of detection impedance electrodes is between 0.5 mm and 1 mm, inclusive.

An impedance assembly, comprising:

• an elongate wire extending from a proximal wire end to a distal wire end;
• a catheter comprising an elongate tube extending from a proximal tube end to a distal tube end, said tube having an exterior surface and defining a tube lumen along the longitudinal axis of the tube, said tube surrounding the wire coaxially;
• a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the wire, both located near the distal wire end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode configured for connection to a data acquisition system near the proximal wire end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode configured for connection to the data acquisition system;
• and
• a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode configured for connection to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode configured for connection to the data acquisition system;
• the impedance assembly configured so that the first detection impedance electrode and the second detection impedance electrode can obtain one or more conductance values within an electric field generated by the first excitation impedance electrode and the second excitation impedance electrode, and wherein a cross-sectional area of a vessel can be calculated based in part upon the one or more obtained conductance values and a known distance between said first detection impedance electrode and said second detection impedance electrode;
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.

A system for measuring a cross-sectional area of a targeted treatment site, comprising:

• an impedance assembly;
• a solution delivery source for injecting a solution through the assembly and into the treatment site;
• a current source;
• and
• a data acquisition and processing system that receives conductance data from the assembly and determines the cross-sectional area of the treatment site;
• the impedance assembly configured so to obtain one or more conductance values within an electric field generated by the impedance assembly, and wherein a cross-sectional area of the treatment site can be calculated based in part upon the one or more obtained conductance values and a known distance between a first detection impedance electrode and a second detection impedance electrode of the impedance assembly;
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.

An impedance assembly, comprising:

• an elongate wire extending from a proximal wire end to a distal wire end;
• a first excitation impedance electrode and a second excitation impedance electrode along the longitudinal axis of the wire, both located near the distal wire end, said first excitation electrode comprising a first excitation impedance lead extending from said first excitation electrode configured for connection to a data acquisition system near the proximal wire end, said second excitation electrode comprising a second excitation impedance lead extending from said second excitation electrode configured for connection to the data acquisition system;
• and
• a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes, said first detection electrode comprising a first detection impedance lead extending from said first detection electrode configured for connection to the data acquisition system, said second detection electrode comprising a second detection impedance lead extending from said second detection electrode configured for connection to the data acquisition system;
• the impedance assembly configured so that the first detection impedance electrode and the second detection impedance electrode can obtain two or more conductance values within an electric field generated by the first excitation impedance electrode and the second excitation impedance electrode, and wherein a cross-sectional area of a vessel can be calculated based in part upon the two or more obtained conductance values and a known distance between said first detection impedance electrode and said second detection impedance electrode;
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.

An impedance assembly, comprising:

• an elongate wire extending from a proximal wire end to a distal wire end;
• a first excitation impedance electrode and a second excitation impedance electrode along a longitudinal axis of the wire, both located near the distal wire end, and
• a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes, the first detection impedance electrode and the second detection impedance electrode separated by a known distance so that the first detection impedance electrode and the second detection impedance electrode can obtain one or more conductance values within an electric field generated by the first excitation impedance electrode and the second excitation impedance electrode;
• wherein a cross-sectional area of a vessel can be calculated based in part upon the two or more obtained conductance values and the known distance between said first detection impedance electrode and said second detection impedance electrodes
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.

An impedance assembly, comprising:

• an elongate wire extending from a proximal wire end to a distal wire end;
• a first excitation impedance electrode and a second excitation impedance electrode along a longitudinal axis of the wire, both located near the distal wire end, and
• a first detection impedance electrode and a second detection impedance electrode along the longitudinal axis of the wire, both located in between the first and second excitation electrodes;
• the impedance assembly configured so that the first detection impedance electrode and the second detection impedance electrode can obtain two or more conductance values within an electric field generated by the first excitation impedance electrode and the second excitation impedance electrode, and wherein a cross-sectional area of a vessel can be calculated based in part upon the two or more obtained conductance values and a known distance between said first detection impedance electrode and said second detection impedance electrode;
• wherein the known distance between said first detection impedance electrode and said second detection impedance electrode is between 0.5 mm and 1 mm, inclusive.