A wide range of vascular lesions are amenable to safe and effective treatment by a class of lasers that take advantage of the principle of selective photothermolysis (see also Chapter 239).
Vascular lesions can be a significant cosmetic concern for some patients and are generally amenable to laser treatment. Telangiectasias are small, superficial cutaneous blood vessels often appearing on the nose, cheeks, and chin in fair-skinned individuals as a result of actinic damage or rosacea. Other causes of telangiectasias include collagen vascular disease, genetic disorders, hormonal disorders, primary cutaneous disease, and radiation dermatitis. Telangiectasias are often associated with facial erythema, which can manifest as a flushing or blushing disorder. Various laser treatments can target this background erythema in addition to treating the discrete vascular lesions.
Other types of vascular lesions, including cherry and spider hemangiomas, venous lakes, and angiokeratomas, may respond to vascular laser treatment (Fig. 252-4). Poikiloderma of Civatte, which manifests as a combination of telangiectasia, irregular pigmentation, and atrophic changes in fair-skinned individuals with actinic damage, can also be treated with vascular lasers. Extreme caution must be used when treating this condition, because overly aggressive treatment can worsen the atrophy and hypopigmentation.
Venous lake treated with a potassium-titanyl-phosphate laser. A. Before treatment. B. After treatment.
In addition to improving vascular lesions, vascular laser treatments can improve the appearance of hypertrophic scars and keloids. Vascular lasers not only reduce the erythema by eliminating the underlying dilated microvasculature in a scar, they can also reduce the height of the scar and improve the skin surface texture. Multiple treatment sessions are required, and the treatment can be augmented by intralesional injections of corticosteroid with 5-fluourouracil. Newly formed atrophic scars, such as striae rubra, can sometimes be greatly improved with vascular laser treatment, whereas older lesions are less responsive.
Laser treatment of vascular lesions is relatively safe but not without risks (Table 252-3). Higher-energy treatments or treatments with overlapping passes can result in atrophic or hypertrophic scarring. Alterations in pigmentation may result due to the concomitant absorption of 532-nm light by epidermal melanin. Patients with tans or darker skin types must be treated with caution to avoid pigmentary changes.
Table 252-3 Treatment of Vascular Lesions: Associated Risks ||Download (.pdf)
Table 252-3 Treatment of Vascular Lesions: Associated Risks
- Postinflammatory hyperpigmentation
- Postinflammatory hypopigmentation
- Atrophic scarring
- Hypertrophic scarring
Most cosmetic vascular laser treatments are performed in the office. The patient's eyes are protected with laser surgery goggles or with intraocular metal eye shields if treatment around the eye is required. All clinical personnel must wear laser surgery glasses that specifically absorb the wavelength of light used in the treatment. Flammable gases and other materials must not be present, because vascular lasers are capable of igniting fires.
Vascular lesions were one of the first targets of treatment with early lasers. These early lasers, such as the argon laser (488 nm, 514 nm), argon-pumped tunable laser (488–638 nm), copper and bromide lasers (578 nm), potassium-titanyl-phosphate (KTP) laser (532 nm), and krypton laser (568 nm), emitted continuous energy that was absorbed by oxyhemoglobin in cutaneous blood vessels (Chapter 239). Their use was limited because the continuous thermal energy often resulted in scarring and pigmentary alterations. The development of pulsed lasers in the 1980s allowed for more precise targeting of the oxyhemoglobin-containing vessels with less thermal and mechanical injury of surrounding tissues (Table 252-4). It is believed that pulsed energy delivered with short pulse widths causes intravascular cavitation, vessel wall fragmentation, and hemorrhage, whereas pulsed energy delivered over longer intervals causes intravascular coagulation and collagen contraction within the vessel wall and surrounding tissue. To reduce epidermal damage, all vascular lasers use an epidermal cooling system, with a cryogen spray or contact cooling.
Table 252-4 Treatment of Vascular Lesions: Equipment ||Download (.pdf)
Table 252-4 Treatment of Vascular Lesions: Equipment
- Pulsed potassium-titanyl-phosphate lasers
- Pulsed dye, long-pulsed dye, variable-pulsed dye lasers
- Long-pulsed infrared lasers: alexandrite, diode, neodymium:yttrium-aluminum-garnet (Nd:YAG)
- Multiplex lasers: sequential pulsed dye + Nd:YAG
- Intense pulsed light devices
The flashlamp-pumped PDL uses a high-power flashlamp to excite an organic dye (rhodamine) and produces a pulse of yellow light that is absorbed by oxyhemoglobin. The newer PDLs can deliver a variety of fluences over variable pulse durations (0.45–40 ms) to effectively treat many cosmetic conditions (see also Chapter 239). These PDLs can deliver high-energy, shorter pulses of light to treat striae distensae rubra, keloids, CVM, and infantile hemangioma. Purpura often results at these settings but resolves within 1–2 weeks. However, the device is most useful in treating facial erythema and facial telangiectasias at longer pulse durations that do not lead to purpura, which is a barrier to treatment for some patients.
The long-pulse, frequency-doubled Nd:YAG-KTP lasers emit a green 532-nm light that can also improve telangiectasias with minimal purpura. The current KTP lasers deliver energy with pulse durations of 1–100 ms through a fiberoptic handpiece with contact cooling. Although the 532-nm light is strongly absorbed by hemoglobin, the laser has a limited depth of penetration, which makes it useful for treatment of superficial facial vessels. Because melanin also absorbs 532-nm light, this laser should be used with caution in patients with darker skin phototypes.
Long-pulsed infrared lasers such as the alexandrite (755 nm), diode (800 nm), and Nd:YAG (1,064 nm) lasers allow deeper penetration into the skin, but their light is absorbed less specifically by hemoglobin than is the light of other vascular lasers (see also Chapter 239). There is still enough absorption, however, to treat superficial and deep reticular veins (up to 3 mm in diameter) in patients with a variety of skin types. More recently, multiplex lasers have been developed that sequentially deliver a PDL (595-nm) pulse followed by an Nd:YAG (1,064-nm) pulse at precise intervals. It is theorized that the first PDL pulse induces blood clot formation and methemoglobin conversion, which allows for greater absorption of the Nd:YAG energy. Studies are ongoing to delineate the cosmetic and medical indications for multiplex laser treatment.
IPL devices with cutoff filters that deliver increments of light ranging from 515–590 nm have been shown to be effective in the treatment of cosmetic vascular conditions. IPL devices produce a variety of fluences (up to 80 J/cm2) over 2–10 ns in single-, double-, or triple-pulse modes. The light is delivered by a fiber through an 8 × 15 mm or 8 × 35 mm glass window that is pressed directly against the skin. A coupling gel is applied to the skin before light application to protect the epidermis from overheating and improve light penetration. Compared with PDLs, IPL devices require a longer treatment session and potentially a greater number of treatments to achieve similar results.
Vascular lasers and light sources used for cosmetic indications produce a brief stinging or burning sensation. Treatments are generally tolerated without anesthesia. Because discomfort can build with cumulative laser pulses, treatment of lesions with large surface areas may require topical anesthesia with a eutectic mixture of prilocaine and lidocaine or topical lidocaine. Topical anesthetics are removed a few minutes before treatment to reduce vasoconstriction and interference with laser light delivery. Rarely, local anesthesia with lidocaine or nerve blocks are required for full-face treatment.
The technique for treatment of vascular lesions will depend on the type and size of vessel to be treated and the patient's skin type. PDL treatments are delivered through a handheld fiber-optic device with a spot size ranging from 2–12 mm. The pulses are placed adjacent to each other with approximately 18% overlap to avoid missing areas between pulses. In general, lower fluences are used to treat macular lesions, whereas higher fluences are used to treat more hypertrophic lesions. At short pulse durations, a light gray discoloration of the treated area is the therapeutic endpoint, whereas at long pulse durations transient purpura lasting 1–2 seconds is the desired endpoint. Pulsed KTP laser treatment is delivered using a handpiece held perpendicular to the skin surface, and the vessels are traced individually at a speed that heats them without causing epidermal damage. Effective treatment will cause vessels to disappear with a subtle blanching effect.
IPL is delivered with a shorter-wavelength filter (515 nm) in single-pulse mode to treat fine superficial vessels in patients with skin phototype I. Longer cutoff filters (570–590 nm) and double- or triple-pulse modes are needed to treat large and deeper vessels. A layer of cool water gel 1–2 mm thick is applied to the skin, and then test spots are treated at increasing fluences until a faint erythema without epidermal damage is achieved. The individual pulses are applied adjacent to each other with minimal overlap. A second pass may be made perpendicular to the first pass to prevent reticulation.
The efficacy of laser and light treatment of vascular lesions depends on the caliber and depth of treated vessels. Small superficial vessels are more responsive than larger, deeper vessels. Lesions with a high blood flow, such as some spider angiomas, are also more difficult to treat. Patient response is assessed at 4–6 weeks after treatment, and treatments are repeated if necessary.
Immediately after treatment, patients may experience erythema and edema, which may last for the next 1–2 days. Patients who are treated with a PDL at short pulse durations will develop purpura, which gradually resolves in 1–2 weeks. Crusting, blistering, and scarring may result from overtreatment with any vascular laser. With all long-pulsed infrared lasers, adequate epidermal cooling is critical to minimizing the risk of epidermal damage and scarring. Given the overlapping absorption spectrum of epidermal melanin, vascular laser treatment can cause hyperpigmentation or hypopigmentation, but this is rarely observed. Suntanned patients and patients with darker skin phototypes should not be treated with KTP, PDL, or IPL devices.
Application of cold dressings or ice can help minimize the erythema and edema that develop in the first 24 hours after vascular laser treatment. Crusted or blistered areas should be treated twice a day with petrolatum until they have resolved. Patients requiring multiple treatments should wear sunscreen daily to prevent the risk of laser energy absorption by epidermal melanin in subsequent treatments.