Treatment endpoints for resistant port wine stains with a 755 nm laser.

Laser therapy of port wine stains (PWS) resistant to pulsed dye laser is challenging and controversial. Based on the theory of selective photothermolysis, vessels in such lesions may be specifically targeted with the laser wavelength of 755 nm. There is much deeper penetration of the near-infrared light and it is difficult to visualize laser-induced changes within the deeper dermis. The recognition of an appropriate immediate endpoint response with this wavelength would be helpful. This is a clinical observations report. We present examples of an appropriate PWS tissue response endpoint based on our clinical observations in resistant PWS treated with a 755 nm laser at high fluences (40-100 J/cm(2)), 1.5-ms pulse duration, with dynamic cooling device (DCD) cooling. Mild-to-moderate PWS lightening was associated with the immediate endpoint of a transient gray color that gradually evolved into persistent deep purpura within several minutes. We also discuss the clinical endpoints that represent undertreatment and overtreatment of PWS. It is important to attain, and maintain, the correct endpoint when treating PWS with this deeply penetrating near-infrared laser at high fluences in order to (a) induce lesional lightening, and (b) avoid deep dermal burns that may produce scarring. Judicious use of the 755 nm laser can be beneficial for resistant PWS.