In the 1960s, laser technology was first used to treat vascular lesions. However, the continuous wave low-power laser used at that time ablated the blood vessels in a manner similar to cauterization, but this method caused obvious thermal damage to the surrounding and deep tissues, which easily led to scar formation and depigmentation.

In 1983, the introduction of the theory of selective photothermal effect brought revolutionary changes to the laser treatment of vascular lesions. With the continuous development of modern science and technology, many new laser treatment theories and equipment have emerged, significantly expanding the scope of indications for laser treatment. At present, the main indications for laser treatment of vascular lesions include hemangiomas, port wine stains, varicose veins in the legs, and telangiectasia on the face.

Vascular lesions on the face and legs are common problems in skin cosmetic treatments. Laser treatment of vascular lesions in the legs is particularly difficult due to the wide range of lesions, deep blood vessels, complex blood flow changes, high intravascular pressure, and various dilation types. A study from Turkey reported the efficacy and safety of long-pulse 1064nm Nd:YAG laser in the treatment of vascular lesions of the face and legs. The following is an introduction to the relevant content:

A total of 145 subjects were included in the study. All of these subjects suffered from varying degrees of facial telangiectasia or leg vascular lesions and were divided into facial group and leg group according to the location of the lesions.

This study only included patients with lower extremity venous insufficiency grade I to II (see Table 1 for specific grading criteria), and all subjects underwent color Doppler ultrasound examination of the lower extremity veins before surgery to clarify the patency of the saphenous vein and its tributaries.

Exclusion criteria: pregnant or lactating women, hypercoagulable state, systemic diseases, photosensitivity of the skin, Fitzpatrick skin phototype V-VI, history of keloid or hypertrophic scars, and age less than 18 years old.

Grouping and treatment parameters: The diameter of the blood vessels was measured and divided into two groups according to the diameter size: diameter between 0.5 and 3 mm, and diameter greater than 3 mm. The treatment parameters (energy, pulse width, spot size) were personalized according to the blood vessel diameter and lesion location. All patients were treated with a long-pulse 1064 nm Nd:YAG laser with a spot size of 3-7 mm, an energy density of 80-280 J/cm², and a pulse width of 10-20 ms. The treatment device was equipped with epidermal temperature regulation and an independent cooling system. No local anesthesia was required, and most subjects could tolerate it. All subjects received 2 treatments, with an interval of 4 weeks between the two treatments. Within 10 days after the end of the treatment, the subjects were required to pay attention to sun protection and strengthen local care of the treated area. The evaluation time points were baseline, before the second treatment, and 4 weeks after the second treatment.

Efficacy evaluation: Two professional dermatologists evaluated the improvement of venous dilation in photos before and after treatment, and divided it into the following four levels: <25% improvement (mild); 25%~50% improvement (moderate); 51%~75% improvement (good); >75% improvement (significant).

Satisfaction survey: After the treatment, all patients were asked to rate their satisfaction based on a four-point questionnaire scale: 1=unsatisfied; 2=slightly satisfied; 3=satisfied; 4=very satisfied.

Adverse reaction record: All adverse reactions experienced by patients during the follow-up period were recorded, including but not limited to erythema, burning sensation, blisters, post-inflammatory pigmentation, hypopigmentation, scars, etc.

A total of 145 subjects were included in this study, including 137 females (accounting for 94.5%) and 8 males (accounting for 5.5%). All subjects completed the established treatment plan. The average age of the subjects was 44.1±11.0 years old, with an age range of 19 to 76 years old. According to Fitzpatrick skin classification, the subjects with skin types II, III and IV accounted for 46.2%, 44.8% and 9.0%, respectively. According to the lesion site, there were 92 subjects in the facial group (accounting for 63.4%) and 53 subjects in the calf group (accounting for 36.6%). In terms of blood vessel diameter, 59.3% of the subjects had a diameter of 0.5-3mm, while 40.7% had a blood vessel diameter greater than 3mm.

▲Figure 1. Facial capillary dilation in a 40-year-old woman. Left) Before treatment; Right) After treatment

▲Figure 2. Capillary dilation in the legs of a 57-year-old woman. Left) Before treatment; Right) After treatment

The evaluation results of professional physicians are shown in Table 2:

The efficacy of different treatment areas was further analyzed, and the results are shown in Table 3. Statistical analysis showed that there was no significant difference in the clinical efficacy of long pulse width 1064nm Nd:YAG laser in improving vascular dilation in the treatment areas of the face and legs.

Patient satisfaction: After 8 weeks, 118 patients (81.3%) were very satisfied with the treatment results, and 26 patients (17.9%) were satisfied with the treatment results.

Adverse reactions: 64.8% of the subjects did not report adverse reactions. Table 4 shows the incidence of adverse reactions. The most common adverse reaction was erythema (12.4%), followed by burning sensation (9.0%) and post-inflammatory pigmentation (7.6%).

According to the principle of selective photothermal effect, the target of laser treatment of skin vascular lesions is oxygenated hemoglobin. Oxygenated hemoglobin has three main absorption peaks in the visible spectrum, located at 418nm, 542nm and 577nm, among which the best absorption peak is located in the 577~600nm band. Because the 418nm wavelength has a shallow depth of action in the tissue, it is rarely used clinically. In the treatment of modern skin vascular diseases, commonly used lasers are mainly concentrated in wavelengths near the two absorption peaks of 542nm and 577nm, such as long-pulse frequency-doubled Nd:YAG laser (532nm) and 585nm pulse dye laser, which are typical representatives in this field.

▲Figure 3 Oxyhemoglobin absorption curve

This study confirmed that long-pulse 1064nm Nd:YAG laser can effectively treat facial telangiectasia and lower limb vascular lesions. However, it should be noted that the study only included patients with grade I~II lower limb venous insufficiency, and excluded patients with grade III and above vascular lesions. Therefore, the judgment of its efficacy is based on strict screening and reasonable selection of indications.

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