Intraluminal guidance system using bioelectric impedance

• US 7,854,740 B2
• Filed: 04/02/2009
• Issued: 12/21/2010
• Est. Priority Date: 04/27/2006
• Status: Expired due to Fees

• Current Assignee: Medtronic Vascular (Medtronic Plc), Medtronic Vascular, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Inventors: Carney, Alan
• Primary Examiner(s): Hindenburg; Max
• Assistant Examiner(s): Stout; Michael C
• Application Number:
  US12/417,363
• Publication Number:
  US 20090192405A1
• Time in Patent Office: 628 Days
• Field of Search: 600/547, 600/585, 600/373, 606/159
• US Class Current: 606/159
• CPC Class Codes: A61B 17/320758 with a rotating cutting instrument, e.g. motor driven A61B17/320725, A61B17/32075 and A61B17/320783 take precedence; for removing intra-ocular material A61F9/00763; endoscopic rotatable cutting instruments A61B17/32002
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/22042 Details of the tip of the guide wire
• CPC Class Codes: A61B 2017/22044 with a pointed tip
• CPC Class Codes: A61B 2017/22094 for crossing total occlusions, i.e. piercing

Abstract

A system using bioelectric impedance to guide a flexible elongate transluminal device through an occlusion in a vessel. The device can be a guidewire or a device for performing an atherectomy, discectomy, ablation or similar technique. The device includes a first electrode disposed on a distal portion of the device. A second electrode is disposed in electric contact with the patient separate from the first electrode. An electric current is supplied between the first and second electrodes and a voltage drop is measured between the first and second electrodes. The voltage drop is converted to bioelectric impedance. Based on the impedance measurement, a clinician can determine if the device is approaching the vessel wall, permitting the clinician to redirect the device away from the vessel wall.

Claims

1. A method for guiding a device through an occlusion in a patient'"'"'s vessel, the method comprising the steps of:

delivering a flexible elongate steerable medical guidewire transluminally to the occlusion, wherein a first electrode is disposed on a distal tip of the guidewire;

advancing the guidewire distal tip into the occlusion;

placing on the patient a second electrode separate from the first electrode and in electrical contact with the patient, wherein the second electrode is a skin electrode;

coupling an electric power source to the first and second electrodes;

activating the power source to provide an electric current between the first and second electrodes;

measuring a voltage drop between the first and second electrodes;

calculating a bioelectric impedance based on the measured voltage drop between the first and second electrodes; and

continuing to advance the guidewire distal tip through the occlusion while directing the guidewire tip away from the vessel wall when the calculated impedance reaches a predetermined bioelectric impedance value.

2. The method of claim 1, wherein the step of activating the power source to provide a current between the first and second electrodes takes place in a pulsed sequence.

3. The method of claim 2, wherein the impedance is calculated each time a current is provided between the first and second electrodes.

4. The method of claim 1, further comprising the step of advancing the guidewire through the occlusion as the current is applied between the first and second electrodes.

5. The method of claim 1, further comprising, prior to advancing the distal tip into the occlusion, the steps of:

positioning the first electrode in electrical contact with the vessel adjacent the occlusion;

measuring a voltage drop between the first electrode and the second electrode; and

calculating the predetermined bioelectric impedance value based on the voltage drop between the first second electrodes.

6. The method of claim 1, wherein an alarm is triggered when the calculated impedance reaches a predetermined bioelectric impedance value.