Optimal pulse durations for the treatment of leg telangiectasias with an alexandrite laser

Determine optimal settings using a long pulse 755 nm alexandrite laser in the treatment of superficial leg veins. STUDY DESIGN\

Fifteen patients with Fitzpatrick skin types I-III with telangiectasia ranging from 0.2 to 1.0 mm were enrolled. Spot size varied from 3 to 6 mm. Pulse durations ranged from 3 to 100 milliseconds. For each pulse duration, test sites were performed to determine threshold radiant exposures using persistent bluing and/or immediate stenosis (closure) as the clinical endpoint. Test sites were re-evaluated 21 days later. Optimal settings, those that resulted in the greatest clearance with minimal side effects (pain, purpura, epidermal damage, pigment changes), were used to treat a larger area of like-sized vessels. Follow-up evaluations were conducted 12 weeks after a single treatment using the optimal setting. Polarized digital photographs were obtained at each visit. Improvement was determined by blinded evaluation of pre/post-treatment photographs.

Fourteen patients completed the study. Radiant exposure thresholds for immediate vessel changes depended on vessel diameter, with larger radiant exposures required for smaller spot sizes and smaller vessels. The average threshold radiant exposure for closure was 89 J/cm(2). The optimal pulse duration was 60 milliseconds for most of the patients. With this pulse width, clearance approached 65% 12 weeks after a single treatment. Transient hyperpigmentation occurred in four patients. Increasing the pulse duration improved epidermal tolerance and decreased the likelihood of purpura.

By lengthening the pulsewidth beyond 3 milliseconds, a long pulse alexandrite laser achieves satisfactory clearance with an improved side effect profile.