Optical properties of human arterial thrombus, vascular grafts, and sutures: implications for selective laser thrombus ablation

To determine the optimal wavelength for laser ablation of arterial and graft thrombus, an integrating sphere was used to obtain optical measurements from different depths of abdominal aortic aneurysm thrombi, vascular grafts, and vascular sutures. Arterial thrombus of all depths maintained the wavelength profile of oxyhemoglobin absorption: the magnitude of the absorption coefficient, however, varied with the thrombus depth or age. White vascular materials demonstrated little variation in spectral absorption coefficients. When dyes were present, the suture´s spectral absorption coefficients varied with the dye utilized and the product manufacturer but the nadir of absorption was in the 450-500 nm waveband, consistent with their blue-green color. A simple thermal model was used as an indicator for the radiant exposure (energy/area) that could cause vascular material dehiscence or arterial thrombus ablation