Temporary Purpura After Pdl Treatment
Fig. 2.7. a Telangiectatic residual strawberry hemangioma. b After pulsed dye laser treatment

examine the patient carefully to determine whether visible telangiectatic areas are secondary to venous pressure from deeper varicose veins. In the uncomplicated case, laser therapy or sclerotherapy can be considered. The majority of leg vein telangiectasia are in the range of 0.1 mm to several millimeters in diameter, much larger than the vessels in a PWS, which are 0.1 mm or less. Following the principals of selective photothermolysis, most vessels greater than 0.1 mm will require pulse durations longer than the 0.45 ms short-pulsed dye laser used for PWS. The larger the vessel, the longer the desired pulse duration. In addition, longer wavelengths of light will be required to penetrate more deeply into these deeper dermal blood vessels.

The KTP laser produces green light at 532 nm, which is well absorbed by hemoglobin but penetrates relatively superficially. This laser does produce millisecond domain pulses, which should be appropriate for leg vein telangiecta-sia. However, early results with this laser in the treatment of leg veins using small spots and pulse durations of 10 ms or less were disappointing and inferior to those of the LPDL (West and Alster 1998). McMeekin (McMeekin et al. 1999) used a long-pulsed Nd:YAG laser at 532 nm to treat 10 patients with leg veins less than 1 mm in diameter. A 4 °C-chilled sapphire tip was used. One to three passes were made with fluences of 12 or 16 J/cm2. The spot sizes were 3-5 mm in diameter. Overall, 44% of patients had more than 50% clearance following a single treatment; 94% of patients had postinflammatory hyperpigmentation, which took 6 months to clear. The required higher flu-ence was associated with atrophic scarring in one patient.

Others have used the same laser with a 50-ms pulse and fluences of 18-20 J/cm2 in the treatment of 46 patients with leg veins. In patients with veins less than 1 mm in diameter, 80% had greater than 50% clearance after two treatments. In patients with veins 1-2 mm in diameter, 67% had greater than 50% clearance after two treatments. Side effects were minimal and temporary. Crusting or blistering occurred if the chill tip was not kept continuously in contact with the skin. The KTP laser seems most appropriate for superficial red telangiectasia up to 1 mm in diameter. Because there is significant absorption by melanin at 532 nm, patients with darker skin types or tanned skin will have an increased risk of side effects, including hypo-and hyperpigmentation. Contact cooling does help to reduce this side effect and allow higher fluences.

■ Long-Pulsed Dye Lasers

Based on the theory of selective photothermoly-sis, the predicted pulse duration ideally suited for thermal destruction of leg veins (0.1 to several millimeters in diameter) is in the 1-50-ms domain (Dierickx et al. 1995). Long PDL with wavelengths of 585-600 nm with pulse durations of 1.5 ms or longer are now available. Other investigators have treated 18 patients with leg veins ranging in diameter from 0.6 mm to 1mm. After one treatment at 15 J/cm2 50% of vessels cleared, and at 18 J/cm2 67% of the vessels cleared. Treatments were delivered using an elliptical (2 x 7 mm) spot, which could be aligned over the telangiectasia. Several studies have shown this laser to be efficacious in the treatment of small vessel telangiectasia on the leg.

In another study, 80 patients with 250 leg telangiectasias were treated with the LPDL using fluences of 16-22 J/cm2; ice packs were used to cool the skin before treatment. One hundred per cent clearance was achieved in vessels with diameters up to 0.5 mm and 80% fading in vessels between 0.5 and 1.0 mm. There was no incidence of scarring, thrombophlebitis, and/or telangiectatic matting. Transient hyper-pigmentation occurred in 50% of cases and hypopigmentation in 50 %. Other investigators also found the 1.5-ms PDL effective in treating vessels smaller than 0.5 mm in diameter; 595 nm and 20 J/cm2 with ice cube cooling were the preferred parameters. Side effects included purpura, pigmentary disturbances, and edema. Others (Weiss and Dover 2002) have also observed encouraging preliminary results using a 20-ms pulse duration 595-nm PDL.

■ Long-Pulsed Alexandrite Laser

There is a small peak of hemoglobin absorption in the 700-900 nm (Fig. 2.8) range of wavelengths. This has encouraged the use of longer wavelength lasers such as the alexandrite, diode, and Nd:YAG lasers in the treatment of more deeply situated, larger-caliber leg vein telangiectasia. The long-pulsed alexandrite laser emits light in the near infrared spectrum at 755 nm. The laser, when used with pulse durations of 3-20 ms theoretically penetrates 23 mm in depth into the skin.

Studies have evaluated the long-pulse alexandrite laser in patients with leg vein telangiectasia. By using a variety of different treatment parameters they concluded that optimal results were

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