Using a "non uniform pulse sequence" can improve selective coagulation with a Nd:YAG laser (1.06 microm) thanks to Met-hemoglobin absorption: a clinical study on blue leg veins.

Abstract

Evaluation of the efficacy, on 1-2 mm blue leg telangiectasia, of a 1,064 nm Nd:YAG laser emitting in a non uniform pulse sequence calculated to consider Met-Hb formation during laser irradiation of a blood vessel. A 1,064 nm Nd:YAG laser (Quantel Medical, Athos, France) was used in a non uniform pulse sequence mode, fluences: 300-360 J/cm(2) spot: 2 mm, + 5 degrees C contact cooling. The clinical evaluation was performed on 11 female patients, average age: 43 (25-57) years, phototype I-VI. All subjects were previously examined with Doppler ultrasound. A treatment site (6 x 4 cm) was selected on each patient. The topography of the vessels network was reported on a tracing plastic frame before each session and 6 weeks after the last one. These frames were digitized and the number of vessels was determined using the Digitized Tracing Frames Technique. Side effects were noted before and after every treatment, and 6 weeks after the last one. This study lasted for 10 months. Patients tolerated the procedure without anesthesia. Moderate pain, transient erythema and edema, one hyperpigmentation and one matting were noted. There was no hypopigmentation. 55% (P < 0.002) vessels clearance after one session, 86% after two sessions (P < 0.001), and 98% (P < 0.001) after three sessions were obtained. On two patients, the treatment was completed after two sessions with a full clearance. Data reported in this study were obtained thanks to a computerized calculation of vessels clearance. They are similar or superior to those reported in the literature about 1,064 nm Nd:YAG lasers and leg telangiectasia. Since, it was developed to consider the modification of blood absorption and the methemoglobin formation which leads to an increase of the 1.06 microm wavelength absorption, the non uniform pulse mode emphasizes the efficacy of this 1,064 nm Nd:YAG laser concerning the treatment of blue leg veins telangiectasia between 1 and 2 mm. This mode gives the possibility to deliver high energy while preserving the surrounding tissue and leads to a rapid vessel clearance with reduced pain and few side effects when compared to previously published clinical studies using a 1.06 microm laser.