A comparative study of a 595-nm with a 585-nm pulsed dye laser in refractory port wine stains

Background The pulsed dye laser (PDL) is the treatment of choice for port wine stains (PWS); however, some patients' PWS become refractory to further treatments. Technological advances have enabled new machines with the advent of surface cooling devices to deliver longer wavelengths and higher fluence more safely. These advances have the potential to achieve improved response rates in refractory PWS. There are few studies comparing the efficacy of standard PDL treatments for refractory PWS with the wider choice of treatment variables available from newer PDL machines. Objectives To determine if there is any advantage of using a longer wavelength (595 nm) and pulse widths (1.5 ms, 6 ms and 20 ms) over conventional PDL settings (wavelength 585 nm, pulse width 1.5 ms) in refractory PWS. Methods Eighteen consecutive consenting patients with Fitzpatrick skin types 1-4 with a mean age 35 years (range 17-59 years) with refractory PWS were treated routinely with three separate test areas using 595-nm PDL (using three different pulse width settings of 1.5 ms, 6 ms and 20 ms), compared with test areas treated with 585-nm PDL (pulse width 1.5 ms). All test areas were treated with an identical fluence (15 J cm(-2)), spot size (7 mm) and cooling setting (dynamic cooling 60 ms, delay 60 ms). Results We found a statistically significant advantage of 595-nm PDL (pulse width 1.5 ms) over 595-nm PDL (pulse width 6 ms) (P < 0.05) in the treatment of refractory PWS; however, we found no significant advantage using longer pulse widths of 20 ms compared with 1.5 ms with the 595-nm PDL. There was no statistically significant advantage in using a 595-nm PDL over a 585-nm PDL using identical pulse widths of 1.5 ms, spot size, fluence and cryogen cooling settings; however, the number of directly comparable test areas was smaller. Some individual patients in our study obtained a better response with certain 595-nm PDL settings (pulse width 1.5 ms and 6 ms) compared with 585-nm PDL (pulse width 1.5 ms). Conclusions Our experience of high fluence PDL in the treatment of refractory PWS suggests patients treated with 585 nm (pulse width 1.5 ms) improve to a similar degree as patients treated with 595-nm PDL (pulse width 1.5 ms). However, the use of the 595-nm PDL with longer pulse widths yields no extra advantage. For those patients who have failed to improve with high-fluence 585-nm PDL (pulse width 1.5 ms), test areas using 595-nm PDL (pulse width 1.5 ms and 6 ms) should be undertaken to ascertain if individual patients may benefit from the longer pulse width 595-nm PDL.