Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
2002-02-08
2003-10-28
Imam, Ali M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S466000, C607S122000
Reexamination Certificate
active
06638222
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to medical devices in general, and in particular to catheter ablation systems for revascularizing occluded vessels.
BACKGROUND OF THE INVENTION
One common form of vascular disease is characterized by deposits that form in a patient's arteries or veins. Once such blockages form in cardiac arteries, they are a significant factor in the occurrence of heart attacks.
In addition to cardiac bypass surgery, new less-invasive techniques such as balloon angioplasty or rotational ablation are being used to treat occluded vessels. In the case of rotational atherectomy, a high speed abrasive burr is routed through the patient's vasculature to the point of the occlusion and used to bore a new lumen through the occlusion in order to restore blood flow. The success of balloon angioplasty and rotational ablation often depends on the nature of the material blocking the vessel. These techniques generally work best when the material is not highly calcified or does not completely occlude the vessel. Total chronic occlusions are typically characterized by a hard calcified material that completely seals off blood flow in a vessel. Some success has been achieved in treating these blockages by advancing a flexible guidewire to the point of the occlusion and “pecking” at the occlusion to create a pathway through it. The with the guidewire technique is that it is time-consuming and presents a risk of vessel perforation if the guidewire becomes misaligned.
Given the fact that total chronic occlusions account for between 20-25% of all occlusions treated, there is a need for a system that employs a more aggressive ablation mechanism to reduce the treatment time but reduces the likelihood that the ablation mechanism will become misaligned in the patient's vessel in order to provide an effective method of treating this type of vessel blockage.
SUMMARY OF THE INVENTION
To treat total chronic occlusions, the present invention is a combination ultrasound and ablation catheter that provides a physician with an image of the position of the catheter in the vessel and an image of the occluding material. An ultrasound transducer is located at the distal end of a catheter which generates ultrasound signals and receives corresponding echo signals from the tissue. The echo signals are transmitted to an ultrasound processor which produces an image of the vessel. The catheter is rotated by a driveshaft in order to provide a 360° view of the vessel. In one embodiment of the invention, the ultrasound transducer in the catheter is set at an angle such that echo signals are received from a position slightly ahead of the distal end of the catheter.
To create a new lumen in the vessel, radio frequency (RF) ablation energy is transmitted to an electrode that is located at a distal tip of the combination catheter. The RF energy ablates a portion of the occluding material to create a new lumen in the vessel. In one embodiment of the invention, the ultrasound transducer is rotated by a conductive driveshaft. The electrode is electrically coupled to the driveshaft and the RF energy is applied to the driveshaft to be transmitted to the occlusion. The conductive driveshaft is surrounded by a non-conductive sheath. The electrode extends out the distal end of the non-conductive sheath such that RF ablation energy is directed from the exposed electrode and into the occluding material.
According to another aspect of the present invention, the electrode at the distal end of the ultrasound catheter may have a variety of shapes including a concave shape, a convex, hemispherical shape with a roughened outer surface or an expandable tip made of a series of braided wires.
In another embodiment of the invention, the catheter system includes an ultrasound catheter having an ultrasound transducer that is rotated by a driveshaft to images of the vessel and occluding material. The ultrasound catheter is routed in one lumen of a multi-lumen catheter. In another lumen of the multi-lumen catheter is a conductive guidewire. RF ablation energy is applied to the conductive guidewire to ablate the occluding material in the vessel.
In accordance with yet another aspect of the invention, the combination ultrasound and RF ablation catheter is routed through a steerable sheath in order to further above-identified in the placement of the catheter within the vessel. Alternatively, the electrode that delivers the RF ablation energy is incorporated into the steerable sheath, wherein the ultrasound catheter extends through a hole in the electrode at the distal end of the sheath to obtain images of the vessel and occluding material.
REFERENCES:
patent: 5000185 (1991-03-01), Yock
patent: 5024234 (1991-06-01), Leary et al.
patent: 5054492 (1991-10-01), Scribner et al.
patent: 5314438 (1994-05-01), Shturman
patent: 5366443 (1994-11-01), Eggers et al.
patent: 5454809 (1995-10-01), Janssen
patent: 5462529 (1995-10-01), Simpson et al.
patent: 5588432 (1996-12-01), Crowley
patent: 5599346 (1997-02-01), Edwards et al.
patent: 5626576 (1997-05-01), Janssen
patent: 5680860 (1997-10-01), Imran
patent: 5683366 (1997-11-01), Eggers et al.
patent: 5740808 (1998-04-01), Panescu et al.
patent: 5749914 (1998-05-01), Janssen
patent: 5817092 (1998-10-01), Behl
patent: 5848969 (1998-12-01), Panescu et al.
patent: 5967984 (1999-10-01), Chu et al.
patent: 6032673 (2000-03-01), Savage et al.
patent: 6045532 (2000-04-01), Eggers et al.
patent: 6165127 (2000-12-01), Crowley
patent: 6241744 (2001-06-01), Imran et al.
patent: 6394956 (2002-05-01), Chandrasekaran et al.
patent: WO 90/07303 (1990-07-01), None
patent: WO 97/45157 (1997-12-01), None
Slager, C.J. et al., “Spark Erosion and Its Combination with Sensing Devices for Ablation of Vascular Lesions,” Chapter 13, in John H.K. Vogel and Spencer B. King, III,Interventional Cardiology: Future Directions, The C.V. Mosby Company, St. Louis, 1989, pp. 157-169.
Chandrasekaran Chandru V.
Guo Zihong
Kaveckis Ryan
Masters Donald
Pantages Anthony J.
Christensen O'Connor Johnson & Kindness PLLC
Imam Ali M.
Sci-Med Life Systems, Inc.
LandOfFree
RF ablation and ultrasound catheter for crossing chronic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with RF ablation and ultrasound catheter for crossing chronic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and RF ablation and ultrasound catheter for crossing chronic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3112004