Methods for laser induced fluorescence intensity feedback control during laser angioplasty

摘要

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.