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Pulsed dye laser irradiation in the wavelength range of 585 to 600 nm is currently the gold standard for treatment of port-wine stains (PWSs). However, this treatment method is often ineffective for deeply seated blood vessels and in individuals with moderate to heavy pigmentation. Use of optical particles doped with the FDA-approved near-infrared (NIR) absorber, indocyanine green (ICG), can potentially provide an effective method to overcome these limitations. Herein, we theoretically investigate the effectiveness of particles derived from erythrocytes, which contain ICG, in mediating photothermal destruction of PWS blood vessels. We refer to these particles as NIR erythrocyte-derived transducers (NETs). Our theoretical model consists of a Monte Carlo algorithm to estimate the volumetric energy deposition, a finite elements approach to solve the heat diffusion equation, and a damage integral based on an Arrhenius relationship to quantify tissue damage. The model geometries include simulated PWS blood vessels as well as actual human PWS blood vessels plexus obtained by the optical coherence tomography. Our simulation results indicate that blood vessels containing micron- or nano-sized NETs and irradiated at 755 nm have higher levels of photothermal damage as compared to blood vessels without NETs irradiated at 585 nm. Blood vessels containing micron-sized NETs also showed higher photothermal damage than blood vessels containing nano-sized NETs. The theoretical model presented can be used in guiding the fabrication of NETs with patient-specific optical properties to allow for personalized treatment based on the depth and size of blood vessels as well as the pigmentation of the individual's skin. [ABSTRACT FROM AUTHOR]

Background. When a cryogen spurt is applied to the skin surface for an appropriately short period of time (on the order of tens of milliseconds), the cooling remains localized in the epidermis, while leaving the temperature of the deeper port-wine stain (PWS) blood vessels unchanged. Objective. The objective of this study was to compare the efficacy and safety of noncooled laser treatment (NC-LT), and cryogen spray cooled laser treatment (CSC-LT) of PWS birthmarks in a large series of patients. Methods. A retrospective review was conducted of 196 patients with head or neck PWS birthmarks treated with the pulsed dye laser (λ = 585 nm; τp = 450 μsec) over a 7-year period. Subjects' ages ranged between 2 months and 62 years; there were 109 females and 87 males, all of whom were Asian. Ninety-eight patients received NC-LT using light dosages of 5–7 J/cm2. Subsequently, 98 patients received CSC-LT using light dosages of 8–10 J/cm2. The primary efficacy measure was the quantitative assessment of the blanching response scores of NC-LT PWSs as compared, on a blinded basis, to CSC-LT PWSs. Results. Based on chi-squared analysis, there were clinical, and statistically significant, differences in the blanching response scores favoring PWS receiving CSC-LT as compared to the NC-LT group (P < .001). Permanent scarring was noted in 3.1% (n = 3) of the patients in the NC-LT group. Permanent scarring was not observed in the CSC-LT treatment group. Transient hyperpigmentation was noted in 57% (n = 56) and 48% (n = 47) of the patients in the NC-LT and CSC-LT groups, respectively. In both groups, the transient hyperpigmentation resolved in all patients within 1 year. Two patients in the NC-LT group developed delayed permanent hypopigmentation. Permanent hypopigmentation was not observed in the CSC-LT group. Conclusion. CSC permitted the use of higher incident light dosages leading to improved PWS clearance without... [ABSTRACT FROM AUTHOR]

Background: The majority of port-wine stain (PWS) patients treated with the pulsed dye laser (PDL) do not achieve complete blanching. Safe administration of higher fluences has been proposed as a means of improving treatment efficacy. Objective: To determine the safety and efficacy of PWS treatment with the 1.5-msec PDL at high fluences in conjunction with cryogen spray cooling. Methods: Twenty PWS patients were treated with the PDL in combination with cryogen spray cooling utilizing a 7 or 10 mm spot size and fluences ranging from 6 to 15 J/cm[sup 2] . Before and after treatment photographs were compared on a blinded basis. Results: No scarring or skin textural changes occurred. Blanching scores were as follows: 20% of patients achieved 75% or greater blanching after an average of 3.3 treatments, 30% achieved 50–74% blanching, 20% achieved 25–49% blanching, and 30% achieved less than 25% blanching. Conclusion: In conjunction with cryogen spray cooling, the PDL can be safely used at high fluences. At this time it is not clear that the use of higher fluences improves treatment efficacy; however, as other aspects of PWS laser treatment are optimized, safe administration of higher fluences is likely to be advantageous. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE. The objective of this study was to determine the effectiveness of a dynamic cooling device (DCD), spraying the skin with a brief spurt of cryogen prior to the laser pulse, in reducing transient pain associated with 585-nm pulsed dye laser (PDL) treatment of port-wine stains (PWS), and reducing epidermal damage (hypo/hyperpigmentation) caused by this laser during PWS treatment.MATERIALS AND METHODS. Matched treatment sites were compared with and without the use of the cryogen spray in 47 patients at two investigational sites. Pain ratings, clearance of the PWS, and pigmentation changes were assessed. The results were analyzed by skin type and patient age. RESULTS. A statistically significant reduction in pain ratings was found in all patient groups using the DEC without changing the efficacy of PWS clearance. Pain reduction was most remarkable in patients with darker skin types. Dynamic cooling prevented the occurrence of epidermal damage or pigmentation change in moist cases. CONCLUSIONS. This study suggests that dynamic cooling can dramatically diminish pain during PWS treatment with the 585-nm PDL without reducing treatment efficacy. The absence of epidermal damage in most patients suggests that precooling with the DCD may allow the use of higher laser fluences to expedite clearance without inducing epidermal change. Dynamic cooling has potential use with other lasers and different lesions where discomfort and epidermal effects limit therapy. [ABSTRACT FROM AUTHOR]