What are lasers
Clinical laser history
Lasers and tissue interactions
Laser treatment anesthesia
Skin care post laser treatment
Laser treatment side effects
Laser treatment legal negligence
Vascular laser treatments
Lasers used in vascular treatments
Port wine stain laser removal
Telangiectases laser removal
Spider angioma laser removal
Cherry angioma laser removal
Pyogenic granuloma laser treatment
Venous lake laser treatment
Hemangioma laser removal
Vascular malformation laser removal
Varicose vein laser treatment
Pigmented skin lesion laser removal
Laser skin resurfacing
Laser scar removal
Laser tattoo removal
Wound healing laser treatments
Laser hair removal
Actinic keratoses laser treatment
Basal cell carcinoma laser treatment
Squamous cell carcinoma treatment
Psoriasis laser treatment
Vitiligo laser treatment
Acne laser treatment
Other skin disease laser treatments
PRK laser eye surgery
LASIK laser eye surgery
LASEK laser eye surgery

  Vascular laser treatment overview

Vascular lesions can be treated with laser techniques called continuous wave (CW) and Pulsed Delivery Lasers (PDL). The chromophore targeted is oxyhemoglobin, although melanin absorption also takes place, mainly at shorter wave lengths. Penetration is approximately 1mm and is greatest at the longest wave lengths.

Pulsed laser (PDL)

Pulsed laser was initially developed for specifically treating vascular lesions and is now preferred since the pulsed delivery limits thermal damage. Also, due to low melanin absorption, irregular pigmentation is less. Earlier, the pulse duration was shorter and considerably less than the thermal relaxation time of superficial blood vessels, causing less thermal damage to untargeted tissues. In the newer system, the pulse duration is more, allowing treatment of large diameter blood vessels, and the wave length is longer, allowing greater penetration. The new systems operate at wave lengths between 585nm and 600nm.

Currently PDL is the standard treatment for childhood vascular lesions, especially port wine stains. In port wine stain treatment there is minimum microvascular and vascular damage, hemorrhage and thermal damage to surrounding tissues. After one week, there is normal epidermis and dermis, demonstrating clearly the superiority of PDL over CW treatment in port wine stain. PDL is best for lesions in lips, neck and eyelids that have thin skin. Deep penetrating longer wave lengths like, yellow light may be needed for lesions located deep.

Local anesthesia may or may not be needed for PDL treatment. Infants and children need sedation and general anesthesia.

Problems in PDL treatment occur when melanin in heavily pigmented skins hinder absorption by deeper vascular structures, increasing risks.

A study on 500 vascular lesions patients, found persistent atrophic scars in less than 0.1%. Permanent hyperpigmentation occurred in 1%, transient hypopigmentation in 2.6% and transient dermatitis in less than 1%. Others found hyperpigmentation at 10% to 15%, mostly in dark skinned patients. Hyperpigmentation slowly cleared in 6 months. Retinal damage and superficial burns also occur.

Continuous wave lasers

Continuous wave (CW) lasers use wave lengths from 488nm to 578nm. At 577nm wave length and above they have the greatest penetration and high selective hemoglobin absorption over melanin. CW lasers cause more thermal damage, compared to pulsed lasers, because the exposure time is inherently not specific to the thermal relaxation time of the target.

CW lasers are often effective for small lesions, especially a type of port wine stains that have mature more deeply pigmented blue purple lesions. Anesthesia is needed when port wine stains are treated with CW laser. Depigmentation can be a problem with CW lasers since most work at 532nm and lower range, where melanin absorption is more.

Types of continuous wave lasers

Argon laser: This was the first vascular specific CW laser and was the standard for many years. The medium is argon. Currently it is used for large blood vessels. The penetration is limited to 1mm, therefore suitable only for superficial lesions. Side effects include crusting that cures in 10 days, scarring, pigment alterations in dark skins, skin texture changes and hypopigmentation. Some consider argon laser superior to PDL for treating port wine stains.

Argon-pumped tunable dye laser (APTDL): This CW laser uses a shuttering mechanism to deliver 30 seconds pulsed lasers. While it can work at a broad range of wave lengths, currently it is designed for two wave length settings of 577nm and 585nm. Because it has a small spot size, the fluence can be very high. Its performance has reportedly been better than argon laser and comparable to PDL in some cases. Blood vessels of sizes large and small can be treated with this laser.

Benign vascular lesions respond best to this laser. Side effects include blanching during treatment and erythema and edema post-treatment. Blistering is not uncommon.

Copper vapor laser: It operates at 578nm wave length with pulse duration of 30 to 50 seconds. Excessive thermal heating due to large number of pulses is avoided by using a shuttering system that limits thermal damage and scarring. Temporary transient hyperpigmentation occurs in 10% patients. This method shows good selective targeting of port wine stains without any damage to non-vascular parts but is not as selective in brown skins due to melanin. There is necrosis of the endothelial without vessel rupture.

Potassium titanium phosphate (KTP) laser: It is a pulsed CW system similar to argon laser. These are now being widely used due to their portability and lower costs. Due to their large spot sizes, vessels larger than those treated by PDL can be treated by this system. There are cooling heads to limit heating, scarring and pigmentation.

Finally, PDL is more expensive and needs more maintenance than the CW system. CW does not cause purpura, while all PDLs cause purpura.

 

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