WHAT ARE THE CRITERIA FOLLOWED WHEN CHOOSING A LASER FOR THE TREATMENT OF VARICOSE VEINS?
A laser is chosen based on 3 parameters: wavelength, energy and pulse duration.
Wavelength is chosen based on the specificity required for a given chromophore.
Energy or fluence must be limited so that the blood continues to absorb energy and does not coagulate but is sufficiently powerful to irreversibly damage the wall of the vein.
Pulse duration must be shorter than the “thermal damage time” (TDT) of the vein and longer than the thermal relaxation time of the blood. In other words, we need to heat the blood long enough to induce sufficient thermal damage in the wall of the vein.
A laser has a different tissue penetration depth depending on the different wavelength and absorption rates used. Selectivity is the product of these two values, which are the criteria to follow when choosing a laser for the treatment of varicose veins. In our case, selectivity is maximum at 585 nm, 910 nm and 1064 nm; choosing 1064 because it has the highest penetration capacity and many varicose veins are found in the deep dermis and so a laser offering maximum penetration is clearly the most appropriate choice. Thus, a laser that can emit at 1064 nm, known as the Neodymium-YAG laser, is the best indicated to treat these deeper lesions.
