Contact assessment of balloon catheters

• US 7,442,190 B2
• Filed: 05/13/2005
• Issued: 10/28/2008
• Est. Priority Date: 05/13/2005
• Status: Active Grant

• Current Assignee: Medtronic CryoCath LP (Medtronic Plc)
• Original Assignee: CryoCath Technologies Incorporated (Medtronic Plc)
• Inventors: Harmouche, Chadi, Mihalik, Teresa Ann, Asmar, Johnny Al, Abbound, Marwan
• Primary Examiner(s): PEFFLEY, MICHAEL F
• Application Number:
  US11/129,205
• Publication Number:
  US 20060259023A1
• Time in Patent Office: 1,264 Days
• Field of Search: 606 20- 26, 606 32- 35, 607/122, 600/506
• US Class Current: 606/21
• CPC Class Codes: A61B 18/02 by cooling, e.g. cryogenic techniques devices for cooling specific reflex points of the body within cell-life limits A61H39/06
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00039 Electric or electromagnetic phenomena other than conductivity, e.g. capacity, inductivity, Hall effect
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2018/0022 Balloons
• CPC Class Codes: A61B 2018/0212 using an instrument inserted into a body lumen, e.g. catheter
• CPC Class Codes: A61B 2090/065 for measuring contact or contact pressure
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/6886 Monitoring or controlling distance between sensor and tissue

Abstract

A method and system for determining contact assessment includes the steps of positioning a catheter at a tissue treatment site, where the catheter has a proximal end portion and a distal end portion, the proximal end portion defining at least one fluid inlet port and at least one fluid outlet port, an expandable membrane defining a cooling chamber a coolant injection lumen in fluid communication with the at least one fluid inlet port and the cooling chamber, a coolant return lumen in fluid communication with the at least one fluid outlet port and the cooling chamber, the coolant injection tube, the cooling chamber, and the primary coolant return lumen defining a fluid pathway and a temperature sensor located near the coolant return lumen; measuring an internal temperature of the chamber, and modifying the position of the catheter in response to the measured temperature. The method and system can also use a measured impedance to determine contact assessment.

Claims

1. A method for determining contact assessment comprising:

positioning a catheter at a tissue treatment site, the catheter comprising;

a proximal end portion and a distal end portion, the proximal end portion defining at least one fluid inlet port and at least one fluid outlet port;

an expandable membrane defining a cooling chamber;

a coolant injection lumen in fluid communication with the at least one fluid inlet port and the cooling chamber;

a coolant return lumen in fluid communication with the at least one fluid outlet port and the cooling chamber, the coolant injection tube, the cooling chamber, and the primary coolant return lumen defining a fluid pathway; and

,

a temperature sensor located near the coolant return lumen;

circulating a cryogenic fluid through the catheter;

measuring an internal temperature of the chamber; and

,

modifying the position of the catheter in response to the measured temperature.

2. The method of claim 1, wherein the catheter is repositioned when the measured temperature is higher than −

80 degrees Celsius.

3. The method of claim 1, wherein the catheter is repositioned when the measured temperature is in the range of −

60 to −

75 degrees Celsius.

4. A method for determining contact assessment comprising:

positioning a catheter at a tissue treatment site, the catheter comprising;

an elongate body defining an injection lumen and an exhaust lumen;

an expandable membrane defining a cooling chamber disposed at a point along the elongate body, the cooling chamber in fluid communication with the injection lumen and the exhaust lumen;

a first electrode located on the distal side of the expandable member; and

a second electrode located on the proximal side of the expandable member;

injecting an electrical current between the first and second electrodes;

measuring an impedance between the first and second electrodes; and

assessing contact between the expandable membrane and the tissue treatment site based at least in part on the measured impedance.

5. The method of claim 4, wherein the catheter system further comprises a control unit.

6. The method of claim 4, further comprising modifying the position of the catheter in response to the measured impedance.