Methods for laser induced fluorescence intensity feedback control during laser angioplasty
First Claim
1. A method for controlling the effectiveness of fluid flushing in a blood vessel, comprising the steps of:
- advancing a catheter through a blood vessel to a region of interest, said catheter including an optical fiber extending therethrough;
introducing a flushing fluid into the region of interest in the blood vessel;
stimulating fluorescence from material in the region of interest adjacent to the distal end of said optical fiber by transmitting through said optical fiber laser radiation having a wavelength and intensity to stimulate such fluorescence;
monitoring the intensity of the fluorescence from material in the region of interest; and
increasing the amount of flushing fluid in the region of interest if the intensity of said fluorescence is representative of less than a desired amount of flushing fluid in the region of interest.
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Accused Products
Abstract
Methods are provided for laser induced fluorescence intensity feedback and control during laser angioplasty. In a first aspect of the invention, a catheter including an eccentric guidewire lumen and at least one optical fiber is positioned relative to an obstruction in a blood vessel by rotating the catheter and monitoring the fluorescence intensity. When the fluorescence intensity has a maximum value, the optical fiber is aligned with the obstruction. In another aspect of the invention, fluorescence intensity feedback is used to determine when a laser ablation device has crossed an occlusion. An abrupt drop in fluorescence intensity indicates that the ablation device has crossed the occlusion. In a further aspect of the invention, fluorescence intensity feedback is used to determine the effectiveness of fluid flushing in a blood vessel. In yet another aspect of the invention, fluorescence spectroscopy and fluorescence intensity monitoring are performed sequentially for different subsets of optical fibers in a laser catheter to provide precise control over fiber positioning, tissue diagnosis and ablation. Preferably, the fluorescence intensity feedback is used in conjunction with fluorescence spectroscopy.
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Citations
11 Claims
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1. A method for controlling the effectiveness of fluid flushing in a blood vessel, comprising the steps of:
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advancing a catheter through a blood vessel to a region of interest, said catheter including an optical fiber extending therethrough; introducing a flushing fluid into the region of interest in the blood vessel; stimulating fluorescence from material in the region of interest adjacent to the distal end of said optical fiber by transmitting through said optical fiber laser radiation having a wavelength and intensity to stimulate such fluorescence; monitoring the intensity of the fluorescence from material in the region of interest; and increasing the amount of flushing fluid in the region of interest if the intensity of said fluorescence is representative of less than a desired amount of flushing fluid in the region of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification