Lasers and IPL systems in the treatment of vascular pathology

Author: Natalya Mikhailova, dermatologist, cosmetologist, member of the American Academy of Dermatology (AAD), certified trainer of Bioscientific Trading LTD (France) and Cynosure (USA), chief physician of the Reform aesthetic medicine clinic, scientific director of the Martinex Medical Center, President of the All-Ukrainian public organization "Union of Mesotherapists", Vice-President of the National Society of Mesotherapy (Russia)

Source: KOSMETIK international journal, No. 2/2013, pp. 66-73

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Vascular skin pathologies include hemangioma, flaming nevus (wine stain), telangiectasia, senile hemangioma, senile hemangioma, arteriovenous and lymphatic malformations.

History of the use of lasers and IPL systems in vascular pathology

Lasers first began to be used to treat vascular pathology in 1970, after the creation of an argon laser with a wavelength of 488 and 514 nm. However, treatment with this laser, which generates continuous radiation, unfortunately very often led to the formation of scars and impaired pigmentation of the skin due to damage to its upper layers. In 1981, continuous wave copper vapor lasers appeared, generating radiation with a wavelength of 578 nm. They were used in the treatment of facial telangiectasia, senile hemangiomas and pyogenic granulomas, but their use was limited to skin phototypes I–II, since patients with phototypes III–V had a high risk of developing dyschromia. In addition to skin pigmentation disorders, the use of copper vapor lasers, which generate continuous radiation, led to burns and scars, which further limited their use. It was only the advent of a pulsed dye laser in 1989, first with a wavelength of 577 nm and then 585 nm, which corresponded to the region of maximum absorption of oxyhemoglobin, as well as the use of effective skin cooling methods, which led to improved clinical results and minimized side effects . Since then, the use of laser technologies in the treatment of vascular formations has become safe and effective.

Currently, CTF laser (532 nm), pulsed dye laser (588 nm), Nd:YAG laser (1064 nm), alexandrite laser (755 nm), diode laser ( 800 nm), as well as combined laser stations emitting sequentially two wavelengths: pulsed dye laser (588 nm) / Nd:YAG laser (1064 nm), alexandrite laser (755 nm) / Nd:YAG laser (1064 nm ).

In the treatment of vascular formations, intense pulsed light systems are also used, which, unlike lasers, generate polychromatic incoherent radiation with wavelengths from 515 to 1200 nm. A similar system was first used in 1976 for the treatment of vascular malformations. At first, the radiation of intense pulsed light systems was in the infrared region of the spectrum, which limited their use in clinical practice, as it very often led to damage to the epidermis, scarring and other complications. In 1990, new high-intensity lamps with filters for the infrared region of the spectrum appeared, which significantly reduced the risk of side effects and complications. Intense pulsed light systems were introduced into commercial use as medical equipment in 1994.

In subsequent years, the use of new technical solutions led to increased safety, expanded range of indications and simplified operation. Currently, skin vascular formations are a key indication for IPL therapy. Due to the wide range of wavelengths, the radiation of these systems is able to reach target vessels located in the skin at different depths. The use of filters at 515, 550, 570, 590 nm is effective in the treatment of telangiectasia, Siwatt's poikiloderma, hemangiomas and flaming nevi.

Operating principle

The action of lasers and incoherent intense pulsed light sources (IPL systems) is based on the principle of selective photothermolysis. The target chromophore is oxyhemoglobin, which has three main absorption peaks - 418, 542 and 577 nm. The optimal absorption is in the range of 577–600 nm [12].

For effective and safe photocoagulation of blood vessels, it is important to consider a number of factors: the diameter of the vessel, the depth of its location, the area of the vascular formation, the size of the laser spot, the pulse duration, the skin phototype, etc.

After absorption of laser radiation by oxyhemoglobin, light energy is converted into thermal energy, which leads to photocoagulation and thrombosis of blood vessels. If the pulse duration exceeds the thermal relaxation time, nonselective thermal damage to the perivascular connective tissue occurs, and subsequently scar formation.

Main factors influencing vascular photocoagulation

For effective and safe photocoagulation of blood vessels, it is important to consider a number of factors: the diameter of the vessel, the depth of its location, the area of the vascular formation, the size of the laser spot, the pulse duration, the skin phototype, etc.

Vessel diameter : using laser and intense pulsed light, pathological vessels with a diameter of 0.1 to 3 mm are eliminated with varying degrees of effectiveness.

Vessel depth : superficial vessels at the level of the papillary dermis respond well to radiation with wavelengths of 577 and 585 nm. The vessels located below the papillary dermis can be treated with radiation with a longer wavelength - 600, 755, 800, 1064 nm.

Localization of vascular formation : superficial red telangiectasias located in the face, neck and chest can be treated with short-wave radiation of 577 and 585 nm. Deeper located blue vessels in the lower extremities, rich in deoxyhemoglobin, absorb radiation well with wavelengths of 755, 800, 1064 nm.

When treating delicate areas with thin skin (periorbital area, neck) or areas prone to scar formation (neck, anterior chest), a reduction in energy flux density of 10–20% is required.

Age of patients . Children and adolescents respond better to treatment compared to adults, which is due to the smaller diameter of the vessels and their location closer to the surface.

Skin phototype . When treating patients with skin phototypes III–V, the chromophore competing with oxyhemoglobin, melanin, should be taken into account. In this case, effective cooling, a larger number of pulses, longer intervals between them and a higher energy flux density are required, since epidermal melanin absorbs laser energy.

Laser radiation parameters

For safe and effective treatment of vascular formations of the skin, it is important to correctly select the radiation parameters of laser systems and intense pulsed light sources. They directly depend on the location of the vascular formation, its type, the depth of the lesion, skin phototype, and the type of laser or IPL system used. To determine individual radiation parameters, a test exposure is carried out.

Spot size . The large size of the light spot improves the penetration of energy into tissues and reduces the degree of its dissipation. Thus, when using a large light spot, effective thermocoagulation of large and deeply located vessels occurs.

The small size of the light spot has a high degree of dispersion and is therefore used in the treatment of small and superficial vessels.

Energy flux density . Energy flux density is the density of laser radiation per unit area. The choice of energy flux density parameters depends on:

• color of the vessel – for photocoagulation of violet and blue vessels, a higher energy flux density is required than for red and pink vessels;
• vessel size - small vessels contain a small amount of oxyhemoglobin, and for their processing radiation with small spots is used, characterized by a high degree of laser energy dissipation, therefore, for effective photocoagulation, high energy flux densities are required;
• blood pressure in the vessel - the vessels on the nose and legs are characterized by high intravascular pressure, therefore, high energy flux densities are used for their thermocoagulation.

Pulse duration . Depends on the diameter of the vessel, the time of thermal relaxation of the vessels and intravascular blood pressure. For vessels with a diameter of 10 to 100 μm, the thermal relaxation time ranges from 1 to 10 ms. Exposure to a pulse whose duration exceeds the thermal relaxation time leads to the spread of heat outside the vessels and damage to surrounding tissues. Thus, the smaller the diameter of the vessel, the shorter the pulse should be, and vice versa: the larger the diameter of the vessel, the longer the pulse should be. The pulse duration is affected by intravascular blood pressure. For effective thermocoagulation of leg vessels with high hydrostatic pressure, along with high energy flux densities, a longer pulse is required.

The use of first generation ILC with short pulse duration, small spot size and high energy density was often accompanied by complications, especially purpura

Classification of vascular lasers

Currently, there are several types of laser and IPL systems that are used to treat vascular formations.

Pulsed dye laser (ICL, 585 nm) . Most widely used for the treatment of vascular formations. It emits pulsed yellow light at 585 or 595 nm, powered by a flash lamp, with pulse durations ranging from 0.45 to 40 ms depending on the laser model. ILK radiation with a wavelength of 585 nm penetrates the papillary layer of the dermis to a depth of 0.2 mm.

The use of first-generation ILCs with short pulse duration, small spot size and high energy density was often accompanied by complications, especially purpura, which appeared immediately after treatment and resolved within 14 days. The latest models of ILC have a pulse duration of 1.5−40 ms, large elliptical spot sizes of 2−7 mm and wavelengths of 590, 595 and 600 nm, which ensures deeper penetration of laser radiation into the skin and high efficiency of thermocoagulation.

The new generation of ILC uses a new pulse structure, where each macropulse is divided into 6–8 micropulses, which allows uniform heating of the vessels and reduces the risk of developing purpura. The range of indications for the use of ILC is wide - these include flaming nevi, telangiectasia, pyogenic granulomas, senile hemangiomas, senile hemangiomas and Siwatt's poikiloderma.

Yttrium aluminum garnet laser with neodymium (1064 nm) . The Nd:YAG laser has a wavelength of 1064 nm. Due to the longer wavelength, the radiation penetrates quite deeply, which makes it possible to coagulate large blue vessels at a depth of 3–5 mm. The absorption coefficient of oxyhemoglobin radiation with a wavelength of 1064 nm is higher than that of surrounding tissues. This difference in absorption coefficients provides selectivity for treating deep blood vessels [11]. Recent studies have shown that heating hemoglobin under the influence of laser radiation causes its oxidation to methemoglobin, which absorbs radiation with a wavelength of 1064 nm 3 times better. Thus, the best therapeutic effect is provided by sequential rather than single impulses.

When treating vessels with an Nd:YAG laser, a variable pulse mode is used, the spot size is 3, 5, 7 and 10 mm, and the energy flux density is up to 300 J/cm2. Adequate cooling and local anesthesia of the treated surface should be provided to reduce swelling, pain and burning, since effective thermocoagulation of blood vessels requires a high energy density. The main indications for the use of Nd:YAG laser are rosacea, facial telangiectasia, Siwatt's poikiloderma, hemangiomas, flaming nevi, senile hemangiomas and varicose veins of the lower extremities. For superficial vascular formations, the spot size is 3 or 5 mm, for large and deep vessels - 5 or 7 mm. The pulse duration is selected based on the diameter of the vessel. All parameters must be adjusted individually, depending on the patient’s skin response to the therapy.

Combined lasers

Pulsed dye laser (585 nm) / Nd:YAG laser (1064 nm) with sequential generation of pulses of two wavelengths. The use of a combined pulsed dye laser (585 nm) / Nd:YAG laser (1064 nm), sequentially generating pulses of two wavelengths, is effective in the treatment of superficial and deep vascular formations. Radiation of two wavelengths following each other has a synergistic effect in photocoagulation of blood vessels. At the same time, the side effects characteristic of using these two lasers separately - purpura and edema - do not occur, since sub-purple radiation doses are used for ILC and the low energy flux density of the Nd:YAG laser does not cause tissue swelling. ILK radiation converts hemoglobin into methemoglobin with the formation of blood microclots that actively absorb in the region of 1064 nm. This allows the use of low energy flux densities of Nd:YAG laser radiation. As a result, the risk of scarring and other side effects is reduced and clinical results are improved. The interval between pulses is set based on the microcirculation index, which must be such that the resulting methemoglobin remains in the vessels.

Alexandrite laser (755 nm) / Nd:YAG laser (1064 nm) with sequential generation of pulses of two wavelengths. A combined system with an alexandrite laser with a wavelength of 755 nm and a Nd:YAG laser with a wavelength of 1064 nm sequentially generates pulses of two wavelengths: first 755 nm, which penetrates quite deeply into the skin, then 1,064 nm. Using this installation, you can also solve vascular problems: treat large, more than 0.4 mm in diameter, deeply located vessels, reticular veins on the face and legs, hemangiomas, which are difficult to treat with other lasers. The interval between pulses can be changed. First, the vessel is irradiated with an alexandrite laser with a wavelength of 755 nm, while methemoglobin and blood microclots are formed from hemoglobin and the absorption of radiation with a wavelength of 1064 nm by the target vein increases by 300−500%. Due to this, the energy flux density of the Nd:YAG laser radiation can be low. The result is less pain during the procedure, less swelling and high efficiency in removing deep veins. Possible limitations of the use of this combined laser are patients with skin phototypes III–V: since the absorption peak of melanin is in the region of 755 nm, this category of patients develops pigmentation disorders of the skin of the treated areas.

Intense pulsed light sources

The intense pulsed light source generates incoherent polychromatic radiation with wavelengths from 500 to 1200 nm. Vascular lesions are a key indication for intense light therapy. To treat vascular formations of different colors, filters of 515, 550, 570, 590 nm are used. The pulse duration and the interval between pulses can be changed. The size of the spot is large enough, so vascular formations occupying a large area can be treated effectively, quickly and with less discomfort [5]. On the other hand, large spot sizes increase the risk of side effects. The radiation generated by intense light sources is characterized by a wide range of wavelengths, due to which it penetrates to different depths: longer waves penetrate into the deep layers of the skin and affect the vessels located there, while shorter waves photocoagulate superficial vessels. However, we should not forget that in the deep layers of the skin the level of absorption of radiation by oxyhemoglobin decreases, therefore, for effective photocoagulation of blood vessels it is necessary to increase the energy flux density. The pulse duration of intense pulsed light sources is quite long - from 2 to 100 ms. In new IPL systems, the pulse is divided into micropulses. In this case, the number, duration and delay time of micropulses in a series can be changed, which ensures cooling of the skin during an outbreak, minimizes pain and leads to uniform heating and coagulation of the vessel.

Due to the rapid dispersion of the light beam, for effective treatment the device's handpiece must be in close contact with the skin, therefore, the doctor cannot observe the reaction of the blood vessels during a flash. In addition, the relatively large working surface area of the device limits maneuverability, especially on concave and convex surfaces, such as the wings of the nose. A sufficiently large weight of the manipule can lead to compression of thin superficial vessels, which affects the effectiveness of treatment. Currently, intense pulsed light sources are successfully used to treat flaming nevi, telangiectasia, rosacea, and Siwatt's poikiloderma.

Features of the initial consultation

• Consultation with an ophthalmologist to exclude glaucoma if the flaming nevus is localized in the area of innervation of the first branch of the trigeminal nerve.
• Consultation with a neurologist when vascular formations are localized in the head and spine to exclude vascular pathology of the brain and spinal cord.
• Consultation with a vascular surgeon for vascular lesions of the legs.

Erythema and swelling of the skin are expected reactions that develop after therapy for vascular formation. The periorbital area and neck are most prone to swelling

Rules for conducting procedures

• Signing the informed consent is mandatory in all cases.
• Photographs of the vascular formation must be taken before each procedure.
• The use of whitening and sunscreen products for patients with skin phototypes III-V should begin at least 2 weeks before the procedure.
• It is mandatory to perform a test exposure to select optimal radiation parameters.
• During the procedure, the doctor and the patient must use glasses to protect their eyes.
• When treating blood vessels on the skin of the eyelids, you should always use protective lenses.
• Data from patients undergoing the procedure are recorded in a separate log. The affected area, radiation parameters, reaction of the vascular formation and surrounding tissues are noted.

Post-procedural period
• After the procedure, the treatment area is cooled with ice packs to provide pain relief and reduce swelling.
• When treating vessels in the periorbital area, patients should sleep with an additional pillow to reduce swelling around the eyes.
• After laser treatment, patients should use a broad spectrum sunscreen.
• To care for the treated area, the patient is recommended to use mild, non-irritating soap and dexpanthenol cream.
• After the procedure, while the skin is healing, patients should not visit the pool, sauna, or engage in contact sports.

Complications and side effects

Pain . The degree of pain depends on the individual pain threshold and the type of laser used. For example, procedures using an Nd:YAG laser are accompanied by quite severe pain. To reduce pain during the procedure, it is necessary to cool the treatment area. Cooling can be air or contact, using ice packs or a sapphire tip. Topical or injectable local anesthetics may be used to reduce discomfort. The procedure may require sedation or anesthesia for children. Anesthesia is used in children under 10 years of age with a large area of vascular formation. The use of local anesthetics in children under 6 months of age is not recommended, as methemoglobinemia and brain hypoxia are possible.

Edema . Erythema and swelling of the skin are expected reactions that develop after therapy for vascular formation. The periorbital area and neck are most prone to swelling. The use of an Nd:YAG laser is often accompanied by the development of edema, which usually subsides on days 5–7. Cooling during and after the procedure reduces swelling.

Bleeding . Bleeding occurs due to incorrect choice of radiation parameters (high energy density and short pulse duration). Correct selection of parameters reduces the incidence of bleeding.

Purpura . Purpura occurs primarily with pulsed dye lasers and is visible immediately after treatment and usually disappears within 7 to 10 days. No specific treatment is required.

Skin pigmentation disorder . As a rule, this complication occurs as a result of incorrect choice of radiation parameters and insufficient cooling of the treatment area, which leads to skin burns and the development of post-inflammatory hypo- or hyperpigmentation. Selecting appropriate settings and properly cooling the skin reduces the risk of burns and pigmentation disorders. Hyperpigmentation is more common in patients with skin phototypes III–V. To correct it, whitening agents are used. With hypopigmentation, skin color usually returns within 3–6 months.

Scars . Scarring typically occurs when high fluences and pulse durations are used, resulting in skin damage and burns. This complication occurs especially often in areas prone to scarring: on the skin of the neck and the front surface of the chest. Selecting the correct radiation settings reduces the risk of scarring.

Recurrence of herpes simplex . This complication often occurs during the treatment of vascular formations on the skin of the face. For patients with a history of herpes simplex, prophylactic use of antiviral drugs is recommended.

Resistance to therapy . Some vascular formations do not respond to treatment. This happens especially often when treating vascular formations on the lower extremities, due to high hydrostatic blood pressure. The patient must be informed about possible resistance at the initial consultation before starting treatment.

At the moment, there are many different ways to treat vascular formations. Lasers and intense pulsed light systems are effective and fairly safe methods of treating pathological vessels. The treatment protocol should be based on a clinical examination of the patient and take into account the skin phototype, depth