Preferential light absorption in atheromas in vitro. Implications for laser angioplasty

Area of Science:

• Biomedical Optics
• Cardiovascular Research

Background:

• Laser angioplasty ablates arterial obstructions but risks thermal damage to normal tissues.
• Selective light absorption by atheromas is crucial for targeted laser treatment.

Purpose of the Study:

• To identify specific light wavelengths for preferential absorption by human atheromas.
• To assess the potential for selective laser ablation of atherosclerotic lesions.

Main Methods:

• Spectrophotometric analysis of human cadaveric atheromas and normal aorta (250-1,300 nm).
• Evaluation of light transmittance and remittance using integrating sphere and tunable-dye laser.
• Analysis via Kubelka-Munk formalism and Beer's law model; chromophore identification.

Main Results:

• Atheromas showed significantly higher light absorption than normal aorta between 420-530 nm.
• At 470 nm, atheroma absorption coefficient was 54 +/- 9 cm-1, compared to 26 +/- 6 cm-1 for aorta.
• Yellow chromophores, identified as carotenoids, were responsible for preferential atheroma absorption.

Conclusions:

• Carotenoids in atheromas preferentially absorb blue light (420-530 nm).
• This selective absorption enables targeted laser angioplasty, potentially reducing collateral thermal damage.
• Further research into blue light laser parameters for atheroma ablation is warranted.