Multiple laser pulses in conjunction with an optical clearing agent to improve the curative effect of cutaneous vascular lesions

Port-wine stain (PWS) birthmark is a congenital microvascular malformation of the skin. A 1064-nm Nd:YAG laser can achieve a deeper treatment, but the weak absorption by blood limits its clinical application. Multiple laser pulses (MLPs) are a potential solution to enhance the curative effect of a Nd:YAG laser. To reduce the pulse number (p_n) required for the thermal destruction of the blood vessel, the effect of glucose in conjunction with MLP was investigated. In vivo experiments were performed on a dorsal skin chamber model. Different concentrations (20, 25, 30, and 40%) of glucose were applied to the sub-dermal side of the hamster skin before laser irradiation. Identical vessels with diameters of 200?±?30 and 110?±?20 μm were chosen as representatives of typical PWS vessels. Instant thermal responses of the blood vessel were recorded by a high-speed camera. The required p_n for blood vessel damage was compared with that without glucose pretreatment. Results showed that the use of glucose with a concentration of 20% combined with MLP Nd:YAG laser to damage blood vessels is more appropriate because severe hemorrhage or carbonization easily appeared in blood vessels at higher glucose concentration of 25, 30, and 40%. When 20% glycerol is pretreated on the sub-dermal hamster skin, the required p_n for blood vessel damage can be significantly decreased for different power densities. For example, p_n can be reduced by 40% when the power density is 57 J/cm². In addition, generation of cavitation and bubbles in blood vessels is difficult upon pretreatment with glucose. The combination of glucose with MLP Nd:YAG laser could be an effective protocol for reducing the p_n required for blood vessel damage. Randomized controlled trial (RCT) and human trials will be conducted in the future.     

New approaches to the treatment of vascular lesions

BACKGROUND AND OBJECTIVE: The pulsed dye laser was developed based on the concept of selective photothermolysis. By using a wavelength of light well absorbed by the target and pulse duration short enough to spatially confine thermal injury, specific vascular injury could be produced. STUDY DESIGN/MATERIALS AND METHODS: Although the pulsed dye laser revolutionized the treatment of port wine stains (PWS) and a variety of other vascular lesions, the ideal thermal relaxation time for the vessels in PWS is actually 1-10 ms, not 450 micros of the original pulsed dye laser machines. These original theoretical calculations recently have been proven correct in a study that used both an animal vessel model and in human PWS. RESULTS: Longer wavelengths of light, within the visible spectrum, penetrate more deeply into the skin and are more suitable for deeper vessels, whereas longer pulse durations are required for larger caliber vessels. CONCLUSION: A variety of lasers recently have been developed for the treatment of vascular lesions which incorporate these concepts into their design, including pulsed dye lasers at 1.5 ms, a filtered flash-lamp pulsed light source with pulse durations of 1-20 ms, several 532-nm pulsed lasers with pulse durations of 1 ms to as high as 100 ms, long pulsed alexandrite lasers at 755 nm with pulse durations up to 20 ms, pulsed diode lasers in the 800 to 900 nm range, and long pulsed 1064 Nd:YAG sources.     

Multiple laser pulses in conjunction with an optical clearing agent to improve the curative effect of cutaneous vascular lesions

Port-wine stains (PWSs) usually respond poorly to pulsed dye laser treatment because of the shallow penetration and light absorption of melanin in the epidermis. Multiple laser pulses (MLPs) Nd:YAG laser in conjunction with an optical clearing agent can help to reduce the total laser energy required for blood coagulation. The quantitative optical clearing effect (OCE) of glycerol was investigated by using a tissue-like phantom. Thereafter, an in vitro capillary tube experimental system and an in vivo hamster dorsal skin chamber experiment for the laser treatment of PWSs were established to visually obtain the quantitative relationship between the OCE and the blood coagulation properties under the irradiation of 1064 nm MLPs. Diffuse reflection coefficient decreases by 36.69% and transmission coefficient increases by 38.73% at 1064 nm, after applying 0.5 mL anhydrous glycerol for 10 min on the surface of the tissue-like phantom. The number of laser pulses required for blood coagulation decreases by 25% after the application of 0.5 mL anhydrous glycerol for 4 min, thrombosis appears after 10 min, and the 0.0854 clotting area completely blocks the capillary tubes in 6 pulses. For 10 min, the incident energy can be reduced by 35.09 and 29.82%. When the 0.3-mm vessel’s buried depths are 1 and 0.5 mm, the pulse number can be reduced from 11 to 8 and from 6 to 4, respectively. Adding anhydrous glycerol directly on the hamster dorsal skin is an effective way to reduce the number of laser pulses from 4～5 to 2～3 for similar capillary tube diameter. Therefore, the MLPs of 1064 nm Nd:YAG demonstrates a substantial curative effect for large capillary tubes. In conjunction with glycerol, this approach may treat deeply buried cutaneous capillary tubes and prevent the unwanted thermal damage of normal dermal tissue.     

Wavelengths for laser treatment of port wine stains and telangiectasia

Background and Objective: This report presents analytical modelling of the influence of wavelength on the amount of volumetric rate of heat produced in dermal blood vessels by millisecond laser radiation. Study design/Materials and Methods: A new anatomical model is proposed that represents port wine stains as well as telangiectatic lesions. It consists of a target blood vessel, representing the deepest dermal blood vessel that requires irreversible injury, and a layer of whole blood, representing all other dermal blood vessels above the target vessel. The laser light that interacts with the blood vessels is assumed to be diffuse. Selective photothermolysis is the basis for the analysis. We consider wavelengths between 577 nm and 600 nm, the argon laser wavelengths at 488/515 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm. Results: The rate of volumetric heat production of absorbed laser light in the target blood vessel is expressed analytically as a function of blood absorption, the concentration of additional dermal blood, and the depth of the target vessel. Conclusion: The model explains why 585 nm is a good compromise for treating port wine stains that vary widely in number of dermal blood vessels. It predicts that wavelengths between 577 nm and 582 nm are excellent for the treatment of port wine stains in young children, and it suggests a possible explanation as to why the argon laser is sometimes said to be capable of treating dark mature port wine stains. The copper vapour laser wavelenght at 578 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm, are predicted to be suitable for the treatment of port wine stains that contain, respectively, a small to moderate and a moderate number of dermal blood vessels. When laser beam spotsize becomes smaller, the best wavelength for producing maximal rate of heat in the target vessel is predicted to shift to 577 nm. © 1995 Wiley-Liss, Inc.     

Thermolysis of port-wine-stain blood vessels: Diameter of a damaged blood vessel depends on the laser pulse length

A thermal model of blood vessel damage during the laser treatment of port-wine stains (PWS) is presented. The model depends on the heat generation in a blood vessel caused by the absorption of laser light and the thermodiffusion of that heat through the dermis. The criterion of vessel injury adopted was an average vessel temperature of 70 °C. Results show that for a chosen combination of pulse length and radiant exposure, only blood vessels within a certain diameter range will be injured. This is in agreement with the pulse length selective photothermolysis criteria suggested previously by Anderson and Parrish (1). The Anderson and Parrish model relies on the cooling behaviour of instantaneously heated vessels, whereas the present study utilizes the heating of the vessel by a Gaussian temporal laser pulse profile. Predictions based on one blood vessel were verified in a skin model with multiple blood vessels by simulating vessel coagulation with a single laser treatment. The diameter of the blood vessels that are damaged during laser treatment of PWS depends on the laser pulse length.     

The influence of morphological distribution of melanin on parameter selection in laser thermotherapy for vascular skin diseases

Port wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age. Currently, laser therapy is the most effective way in clinical management of PWS. It is known that skin pigmentation (melanin content) affects the radiant exposure that can be safely applied to treat PWS. However, the effect of melanin distribution in the epidermis on the maximum safe radiant exposure has not been studied previously. In this study, 10 different morphological distributions of melanin were proposed according to the formation and migration characteristics of melanin, and the two-scale heat transfer model was employed to investigate the influence of melanin distribution on the threshold radiant exposure of epidermis and blood vessels. The results show that melanin distributions do have a strong effect on laser parameter selection. When uniform melanin distribution is assumed, the threshold radiant exposure to damage a typical PWS blood vessel (50 μm diameter) is 8.62 J/cm2 lower than that to injure epidermis. The optimal pulse duration is 1–5 ms for a typical PWS blood vessel of 50 μm when melanin distribution is taken into consideration. PWS blood vessels covered by non-uniformly distributed melanin are more likely to have poor response to laser treatment.     

Laser pulse impact on rat mesenteric blood vessels in relation to laser treatment of port wine stain.

BACKGROUND AND OBJECTIVE: To study the impact of laser pulses on animal microvasculature as a model for laser treatment of port wine stains. STUDY DESIGN/MATERIALS AND METHODS: Rat mesenteric blood vessels were irradiated with a laser pulse (585 nm, 0.2-0.6 ms pulse duration, 0.5-30 J/cm(2) radiant exposure). Video microscopy was used to assess vessel dilation, formation of intravascular thrombi, bubble formation, and vessel rupture. Changes in reflection during a laser pulse were measured by simultaneously recording the temporal behavior of the incident and reflected signals. RESULTS: A threshold radiant exposure of approximately 3 J/cm(2) was found for changes in optical properties of blood in vivo, confirming previous in vitro results. Often, laser exposure induced a significant increase in vessel diameter, up to three times the initial diameter for venules and four times for arterioles, within 200 ms after laser exposure. Arterioles were more likely to dilate than venules. Sometimes, immediately after the pulse, round structures, interpreted as being gas bubbles, were seen within the vessel lumen. CONCLUSIONS: A variety of phenomena can occur when blood vessels of sizes comparable to those in port wine stains are irradiated with laser pulses as used in port wine stain treatment. Thrombus formation and vessel rupture have been described before from histological sections of laser-irradiated port wine stains. However, vessel dilation and formation of non-transient gas bubbles as found in this study have not been described before.     

Long-Term Results with a Multiple Synchronized-Pulse 1064 nm Nd:YAG Laser for the Treatment of Leg Venulectasias and Reticular Veins

BACKGROUND: The long-pulsed Nd:YAG (1064 nm) laser has been shown to be effective in the treatment of blue venulectasias and reticular veins. OBJECTIVE: The present study examined the clinical efficacy and long-term follow-up (12 months) of patients treated with the 1064 nm Nd:YAG laser technology. METHODS: Twenty-five female patients (mean age 37.6 years, Fitzpatrick skin types II-V) were treated with up to three treatment sessions at 6-week intervals on a 5 cm2 surface area of vessels utilizing the 1064 nm Nd:YAG laser with a circulating cooling device. Treatment parameters were vessel size 0.2-2.0 mm treated with a double pulse of 7 msec at 120 J/cm2 and vessel size 2.0-4.0 mm treated with a single pulse of 14 msec, fluence 130 J/cm2, with a spot size of 6 mm. Improvement was judged by double-blinded observer evaluation, macrophotographic imaging, optical chromatography, and a patient evaluation scale. RESULTS: Sixty-four percent of patients treated in the present study achieved 75% or greater clearing of vessels after a maximum of three treatment sessions. Optical chromatography revealed statistically significant decreased chromophore intensity (mean blueness reduction index of 41.2b-). Sixty-four percent of patients were greatly satisfied with the results of the laser treatment. Two patients manifested vessel recurrence when examined at 6 and 12 months, respectively. CONCLUSION: The 1064 nm Nd:YAG laser can produce effective long-term photosclerosis of blue venulectasia and reticular veins. The potential for recurrence should be recognized by the vascular laser surgeon.     

Laser Treatment With a 1064-nm Laser for Lower Extremity Class I–III Veins Employing Variable Spots and Pulse Width Parameters

BACKGROUND: The long-pulsed 1064-nm Nd:YAG laser (employing varying spot sizes, pulse widths, and fluences) has gained popularity for treating lower extremity blue and red vessels that are less than 4 mm in diameter. OBJECTIVE: To evaluate the efficacy of high-power 50-ms 1064 Nd:YAG laser in the treatment of class I-III lower extremity vessels. METHODS: Ten female patients (mean age of 39 years) had a 5-cm2 area of veins measuring 0.2 to 3 mm in diameter treated with up to three treatment sessions using a new 1064 Nd:YAG laser, with the end point being 100% vessel clearing after three treatments. Red vessels were treated with a spot size of 1.5 mm, a fluence of 400 to 600 J/cm2, a pulse width of 30 to 50 ms; blue vessels of 1 to 3 mm were treated with a spot size of 3 mm, a fluence of 250 to 370 J/cm2, and a pulse width of 50 to 60 ms. Macrophotographic imaging evaluations by blinded observers using a quartile scale and a patient satisfaction scale were employed to evaluate results. RESULTS: At month 3 after the final treatment session, 20% of all vessel types had 50% to 75% improvement. Equal clearing was noted for blue and red vessels. At month 6, 80% of patients had a greater than 75% clearing. Ninety percent of patients were highly satisfied with the treatment results at 6 months. CONCLUSION: By varying spot size, fluence, and pulse duration, a long-wavelength 1064-nm Nd:YAG laser can achieve excellent results for treating both blue and red lower extremity vessels that are less than 3 mm in diameter.     

Nd:YAG laser (1064 nm) irradiation for lower extremity telangiectases and small reticular veins: efficacy as measured by vessel color and size.

BACKGROUND: Laser treatment of lower extremity telangiectases and small reticular veins has remained difficult because of vessel color, diameter, depth, and associated high-pressure flow. Traditionally, larger-caliber blue leg veins do not respond well to laser treatment. Nd:YAG laser (1064 nm) irradiation is absorbed by oxyhemoglobin and reduced hemoglobin and is associated with greater depth of penetration than other previously studied vascular lasers. OBJECTIVE: To evaluate a millisecond contact-cooled 1064 nm Nd:YAG laser for the treatment of telangiectases and small reticular veins. METHODS: Twenty-one lower extremity sites, with Fitzpatrick skin types I-IV, received two laser treatments separated by a 4 to 6-week period. Blue and red vessels, ranging in size from 0.25 to 4.0 mm were treated. Pulse durations of 10-50 msec were utilized at fluences of 90-187 J/cm2. Three months after the last treatment, patients were evaluated for vessel improvement and complications. RESULTS: Seventy-one percent of lower extremity vessels had improvement graded as significant. All vessel colors and sizes were successfully treated. The only complication at 3 months was postinflammatory hyperpigmentation. CONCLUSION: 1064 nm Nd:YAG laser irradiation with associated contact cooling is a safe and effective treatment for telangiectases and small reticular veins of the lower extremities.     

Simultaneous irradiation and imaging of blood vessels during pulsed laser delivery

BACKGROUND AND OBJECTIVE: Simultaneous irradiation and viewing of 10-120 microm cutaneous blood vessels were performed to investigate the effects of 2-micros 577-nm dye laser pulses. STUDY DESIGN/MATERIALS AND METHODS: A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability ("threshold") radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage. RESULTS: A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10-30 microm in diameter, but not for larger vessels. For vessels over 60 microm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results. CONCLUSION: These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation.     

Nd:YAG laser-induced morphology change and photothermal conversion of gold nanorods with potential application in the treatment of port-wine stain

Based on the principle of selective photothermolysis, 1064 nm Nd:YAG laser has great potential for the treatment of deeper and larger PWS. However, the clinical effectiveness is limited because of the weak absorption of blood to Nd:YAG laser. The aim of this study is to obtain the optimal irradiation conditions to effectively destroy vascular lesions with the assistance of PEG-modified gold NRs to enhance blood absorption of Nd:YAG laser. In our study, PEG-modified gold NRs were prepared by the seeded growth method. Gold NRs after exposure to Nd:YAG laser were characterized using absorption spectra and transmission electron microscope images. The tissue-like phantom containing a glass capillary with blood was prepared and exposed to Nd:YAG laser to investigate the laser energy density and pulse number required for blood coagulation before and after the addition of gold NRs in blood. The results show that the millisecond Nd:YAG laser irradiation does not result in the shape change of gold NRs. After injection of gold NRs into the bloodstream (4.60 mg/kg), the absorbance of blood at 1064 nm increased 3.9 times. The threshold energy density for the treatment of PWS decreased by 33% (from 30 to 20 J/cm²). Our findings provide an experimental guide for choosing laser parameters and gold NRs concentration for the treatment of deeper and larger PWS with the assistance of PEG-modified gold NRs in vivo in the future.     

A comparative study of temperature elevation on human teeth root surfaces during Nd:YAG laser irradiation in root canals

The purpose of this study was to evaluate the temperatures on the root surfaces during Nd:YAG laser irradiation in root canals using pulse durations of 180 and 320 μs. Thirty extracted human teeth were used in this study. The teeth were enlarged up to ISO 40 (multi-rooted) or up to ISO 60 (single-rooted) by conventional technique using K-files. Then the teeth were placed into a water bath with a constant temperature of 37 °C and then irradiated with an Nd:YAG laser having an output power of 1.5 W, a frequency of 15 Hz, using an optic fiber of 200 μm diameter. The temperature on the root surface was measured by means of attaching thermocouples in three areas (coronal, mesial, and apical regions) of the root canals. The thermographic study showed that the average temperature elevation for both pulse durations on the root surfaces was less than 9 °C. There was no significant difference in the observed temperatures in coronal and mesial areas. Though a higher increase of temperature was observed in the apical region when the pulse length of the Nd:YAG laser was 320 μs. The results of the study showed that the temperature rises during Nd:YAG laser irradiation with parameters used in this study minimal to cause damage on bone and periodontal tissues. Moreover, it was suggested that in order to have lower temperature in the apical region, an Nd:YAG laser with a pulse length of 180 μs is preferred than one with a pulse length of 320 μs.     

Modeling laser treatment of port wine stains with a computer-reconstructed biopsy

BACKGROUND AND OBJECTIVE: The efficacy of laser treatment of port wine stains (PWS) has been shown to be highly dependent on patient-specific vasculature. The effect of tissue structure on optical and thermal mechanisms was investigated for different pulse durations by using a novel theoretical model that incorporates tissue morphology reconstructed tomographically from a PWS biopsy. STUDY DESIGN/MATERIALS AND METHODS: An optical-thermal numerical model capable of simulating arbitrarily complex, three-dimensional tissue geometries was developed. The model is comprised of (1) a voxel-based Monte Carlo optical model, (2) a finite difference thermal model, and (3) an Arrhenius rate process calculation to predict the distribution of thermal damage. Simulations based on previous computer-based reconstruction of a series of 6 microm sections from a PWS biopsy were performed for laser pulse durations (taup) of 0.5, 5.0, and 10.0 ms at a wavelength of 585 nm. RESULTS: Energy deposition rate in the blood vessels was primarily a function of vessel depth in skin, although shading effects were evident. Thermal confinement and selectivity of damage were seen to be inversely proportional to pulse duration. The model predicted blood-specific damage for taup = 0.5 ms, vascular and perivascular damage for taup = 5 ms, and widespread damage in superficial regions for taup = 10 ms. The effect of energy deposition in the epidermis was most pronounced for longer pulse durations, resulting in increased temperature and extent of damage. CONCLUSION: Pulse durations between 0.5 and 5 ms are likely optimal for the PWS analyzed. The incorporation of a tomographically reconstructed PWS biopsy into an optical-thermal model represents a significant advance in numerical modeling of laser-tissue interaction.     

Optimal pulse durations for the treatment of leg telangiectasias with a neodymium YAG laser

BACKGROUND: Leg veins can be effectively treated with lasers. However, the optimal pulse duration for small leg veins has not been established in human studies with a Nd:YAG laser. OBJECTIVES: The purpose of this study was to investigate a range of pulse durations to determine an optimal pulse duration for clearance of leg veins. STUDY DESIGN/MATERIALS AND METHODS: After mapping and photo documentation of the leg veins to be treated, a variable pulse duration Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser (3-100 milliseconds) was used in a single test site session. Pulse durations of 3, 20, 40, 60, 80, and 100 milliseconds were used. At the 3-week follow-up, the optimal pulse duration was defined as that pulse duration which resulted in the most complete clearance of vessels with the least side effects. Up to 20 vessels were then treated using the established "optimal" pulse duration. Final evaluation was at 16 weeks after the initial visit. Three blinded observers rated the percent of vessels completely cleared based on initial and final photographs. RESULTS: Eighteen patients completed the study. Fluence thresholds for immediate vessel changes varied depending on spot size and vessel diameter, with larger fluences required for smaller spot sizes and smaller vessels. Shorter pulse durations (< or =20 milliseconds) were associated with occasional spot sized purpura and spot sized post-inflammatory hyperpigmentation. Longer pulse durations (40-60 milliseconds) achieved superior vessel elimination with less post-inflammatory hyperpigmentation. With a single laser treatment, 71% of the treated vessels cleared. CONCLUSIONS: Compared to shorter pulses (<20 milliseconds), longer pulses may provide gentler heating of the vessel and a greater ratio of contraction to thrombosis.     

The Effects of Variable Pulse Width of Er:YAG Laser on Facial Skin

BACKGROUND: The use of CO2 and Er:YAG lasers for resurfacing has increased significantly in the past few years. Er:YAG laser causes pinpoint bleeding during and after treatment with a typical pulse width of 250 microsec. A longer pulse of Er:YAG laser can potentially coagulate dermal blood vessels and increase the residual thermal damage (RTD). OBJECTIVE: To evaluate the effects of various pulse durations of Er:YAG laser on the depth of RTD and bleeding. METHODS: The preauricular skin of a volunteer was exposed to Er:YAG laser at 250-, 350-, and 700-microsec pulse durations, with a fluence of 5 J/cm2. The number of passes varied between 6 and 16. The treated skin was excised and a histologic evaluation was done. RESULTS: The maximum depth of RTD was 50 microm and there was decreased bleeding with a 700-microsec pulse duration. CONCLUSION: The increased pulse duration of Er:YAG laser of 700 micros does not increase the maximum reported RTD and therefore would not change the recovery time and may have a beneficial effect on hemostasis.     

中重度痤疮1064nm波长可调脉宽Nd∶YAG激光治疗后相关症状和审美评价的影响因素分析

目的:分析中重度痤疮1064nm波长可调脉宽Nd∶YAG激光治疗后患者出现相关症状(瘢痕遗留、色素沉着、局部红斑)的影响因素,了解人群中对中重度痤疮1064nm波长可调脉宽Nd∶YAG激光治疗后影响审美评价的相关因素。方法:回顾性分析在笔者医院皮肤科应用1064nm波长可调脉宽Nd∶YAG激光治疗的89例中重度痤疮患者的临床资料。选取100名外貌正常,具备完整审美能力的普通人作为评价者,根据李克特量表对患者形象进行评分。采用单因素分析和多元Logistic回归模型分析中重度痤疮激光治疗后相关症状和审美评价的影响因素。结果:单因素分析显示,年龄、性别、BMI、吸烟、皮肤类型、初发年龄、病程、发病部位、家族史、伴发病、蠕形螨、尘螨SPT、瘢痕体质均是中重度痤疮激光治疗后相关临床症状的影响因素(P<0.05)。评价者年龄、学历,患者年龄、BMI、皮肤类型、发病部位、瘢痕厚度和瘢痕柔软度是审美评价的影响因素(P<0.05)。多因素Logistic分析显示,性别、家族史、伴发病、蠕形螨及尘螨SPT是中重度痤疮激光治疗后相关症状的独立影响因素(P<0.05)。评价者年龄、患者BMI、皮肤类型和发病部位均是审美评价的独立影响因素(P<0.05)。结论:中重度痤疮1064nm波长可调脉宽Nd∶YAG激光治疗后相关症状与性别、家族史、伴发病、蠕形螨及尘螨SPT有关。中重度痤疮1064nm波长可调脉宽Nd∶YAG激光治疗后的审美评价与评价者年龄,患者BMI、皮肤类型和发病部位有关。     

倍频Nd:YAG 532nm 波长激光治疗皮肤血管异常性疾病的临床应用研究

观察可变脉宽５３２ｎｍ波长激光治疗皮肤血管异常性疾病的效果。用不同脉宽的ＶＰ５３２ｎｍ波长激光结合冷却疗法治疗各种皮肤血管异常性疾病，观察其疗效及并发症。治疗鲜红斑痣、草莓样血管瘤、蜘蛛样血管瘤、血管痣、毛细血管扩张等皮肤血管异常性疾病共１３８例，均取得了满意的疗效，较传统的方法相比，疗效更为明显。可变脉宽５３２ｎｍ波长激光治疗皮肤血管异常性疾病效果可靠，治疗时辅以冷却治疗对防止局部过度损伤及术后色素沉着均有重要意义     

Treatment of port wine stains with the pulse dye laser

The pulsed dye lasers (PDL) are the gold standard in the treatment of port wine stains (PWS). However, clearance rates vary widely, and many lesions are not completely cleared with laser treatment. This article reviews the use of different types of PDL for the treatment of PWS. Longer pulse durations and higher fluences in conjunction with skin cooling are required for larger vessels. Controversy still exists as to which wavelength induces greater photothermal damage to the blood vessels in PWS. The incomplete response of PWS to the conventional PDL is due to the suboptimal irradiation parameters of energy fluence, pulse duration, and wavelength currently used in clinical settings. New-generation PDL are more effective than conventional PDL, but vessels smaller than 30-50 microm appear resistant to all kinds of PDL treatment.     

Description and analysis of treatments for port-wine stain birthmarks

Port-wine stain (PWS) birthmarks are congenital, low-flow vascular malformations of the skin. Lasers are the modality of choice for the treatment of PWS birthmarks, and for most patients the pulsed-dye laser in conjunction with epidermal cooling offers the greatest efficacy and safety. Other light devices, including the 532-nm frequency-doubled Nd:YAG laser, intense pulsed light, 1064-nm Nd:YAG laser, and combined 1064/532-nm system, may be useful during a treatment course for resistant PWS. Laser treatment results in blanching of most lesions, although complete resolution may not occur and some resistant PWS birthmarks respond minimally, if at all. Factors limiting laser treatment include variable vascular geometry, inadequate damage of some vessels, and lesional posttreatment recurrence as a result of neovascularization. Alternative or adjunct treatment options that address these limitations should be explored, including noninvasive real-time imaging to optimize the selection of treatment settings, photodynamic therapy, and perioperative use of antiangiogenic compounds.