In vitro experiment and initial clinical experience in angioplasty, in vascular occlusive disease with a new pulsed dye-laser system

Abstract

The feasibility of using a pulsed dye-laser in angioplasty for detection and disintegration of calcified plaques was studied in vitro. The laser (495 nm wave-length; 2 μs pulse duration) was used as the exciting source for laser-induced-fluorescence (LIF) signals. Spectral data in the 520 to 800 nm region of normal artery wall, calcified plaques, and fibro-fatty plaques were analysed with an optical multichannel analyser. Good signal-to-noise ratio and different spectra for different specimens were obtained within only 2 μs. Fluorescence analysis can be performed in less than 300 ns and therefore the laser can be controlled before plasma threshold is reached. This can lead to a clinical by useful feedback system in an “intelligent” laser, which can selectively ablate atherosclerotic tissue. In a parallel step we investigated a pulsed dye-laser device (504 nm; 1.2 μs) for in vivo recanalisation of arteries in ischaemic lower limbs. A specially designed 9F or 7F guide wire directed multifibre catheter was used for treatment of 17 patients. The recanalisation technical success was 8/8 (4 occlusions/5 stenoses) in the iliac arteries (IA) and 8/9 (8 occlusions/4 stenoses) in the superficial femoral (SFA) and popliteal arteries (PA). All occlusion lengths were below 10 cm. Three early re-occlusions occured, caused by very bad run-off. There was one clinically insignificant SFA perforation and one groin haematoma. Additional techniques (balloon dilatation, stenting, lysis) were considered necessary in 15/17 patients. Mean ankle-arm-index increased significantly in the 1 week examination in rest from 0.61 to 0.76 (P < 0.05) in IA and from 0.65 to 0.93 (P < 0.01) in SFA. Pulsed dye-laser angioplasty promises to be an effective method for plaque ablation/debulking.