INTRALUMINAL GUIDANCE SYSTEM USING BIOELECTRIC IMPEDANCE

• US 20090192405A1
• Filed: 04/02/2009
• Published: 07/30/2009
• Est. Priority Date: 04/27/2006
• Status: Active Grant

• Current Assignee: Medtronic Vascular (Medtronic Plc), Medtronic Vascular, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Vascular, Inc. (Medtronic Plc)
• Inventors: Carney, Alan Oliver
• Granted Patent: US 7,854,740 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• 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. -13. (canceled)

14. :

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

delivering a flexible elongate element transluminally to the occlusion, wherein a first electrode is disposed on a distal portion of the elongate element;

advancing the elongate element into the occlusion;

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

providing an electric power source coupled 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; and

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

18. :

The method of claim 14, wherein the step of activating the power source to provide a current between the first and second electrodes takes place in a pulsed sequence.

19. :

The method of claim 18, wherein the impedance is calculated each time a current is provided between the first and second electrodes.

20. :

The method of claim 14, further comprising the step of advancing the elongate element through the occlusion as the current is applied between the first and second electrodes.

21. :

The method of claim 14, further comprising, prior to advancing the elongate element 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 a predetermined bioelectric impedance value based on the voltage drop between the first second electrodes.

22. :

The method of claim 14, further comprising the step of directing the elongate element away from the vessel wall when the calculated impedance reaches a predetermined bioelectric impedance value.

23. :

The method of claim 14, wherein an alarm is triggered when the calculated impedance reaches a predetermined bioelectric impedance value.

24. :

The method of claim 14, wherein the elongate element is a guidewire.

25. :

The method of claim 14, wherein the elongate element is an atherectomy device.

26. :

The method of claim 25, wherein the atherectomy device includes a cutting head that rotates as the atherectomy device is advanced through the occlusion.

27. :

The method of claim 26, wherein a shut-off switch stops the rotation of the cutting head when the impedance reaches a predetermined level.

28. :

The method of claim 14, wherein the elongate element is a laser ablation device.

29. :

The method of claim 23, wherein the power source provides power to the laser ablation device, and wherein a shut-off switch cuts off power to the laser ablation device when the impedance reaches a predetermined level.

15. -17. (canceled)