Browse Prior Art Database

Lesion-Specific Laser Catheter Angioplasty

IP.com Disclosure Number: IPCOM000040156D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 27K

Publishing Venue

IBM

Related People

Linsker, R: AUTHOR [+3]

Abstract

In laser irradiation of atherosclerotic lesions in blood vessels using a fiber-optic catheter, an important problem limiting clinical applicability is the risk of perforation of the vessel wall resulting from absorption of laser energy. This occurs due to lack of adequate control of beam position and/or of beam penetration depth. The present invention eliminates the risk of excessive beam penetration depth (leading to perforation), and also prevents undesired irradiation of tissue that does not contain atheroma (plaque). Further, it does not require any fine control of the direction of the laser beam or of the positioning of the catheter.

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Lesion-Specific Laser Catheter Angioplasty

In laser irradiation of atherosclerotic lesions in blood vessels using a fiber-optic catheter, an important problem limiting clinical applicability is the risk of perforation of the vessel wall resulting from absorption of laser energy. This occurs due to lack of adequate control of beam position and/or of beam penetration depth. The present invention eliminates the risk of excessive beam penetration depth (leading to perforation), and also prevents undesired irradiation of tissue that does not contain atheroma (plaque). Further, it does not require any fine control of the direction of the laser beam or of the positioning of the catheter. A chemical substance is introduced into the bloodstream of a type that is selectively incorporated into atheromatous plaque and which will fluoresce when appropriately irradiated (with the 'illuminating' beam to be discussed). Thus, an optical signature is provided indicating whether the (small) region being illuminated contains plaque. This signature is used to control the supply of tissue-destroying laser radiation to the same local region. An example of a chemical having these characteristics is a hematoporphyrin derivative (HPD). Such will be referred to as a "labelling chemical" (LC). The device consists of: 1) Two energy sources, one being the irradiating (tissue-removing) laser (TRL), the other being the

illumination source (ILL) which emits at a wavelength

that is absorbed by the LC and causes fluorescence; 2) A switch S1 directing light from either the TRL or the ILL, at any given time, into a fiber-optic catheter 10

that conveys the light to a (generally small) region 12

of vessel wall 14; 3) A fiber-optic tube 16 for conveying the return

(fluorescence) signal from a region of the blood vessel

wall including the small region that may be illuminated

by the ILL at any given time; 4) A detector D for sensing...