Clinical and Optical Coherence Tomography Correlation of Vascular Conditions Treated With a Novel, Variable-Sequenced, Long-Pulsed, 532 and 1,064 nm Laser With Cryogen Spray Cooling

Abstract

BACKGROUND

Patients frequently seek laser treatment for vascular conditions. More recently, a novel 532 and 1,064 nm laser was developed to offer greater flexibility.

OBJECTIVE

A prospective clinical trial evaluated the safety and efficacy of a novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling (DermaV, Lutronic, South Korea).

MATERIALS AND METHODS

Subjects with vascular conditions were enrolled for laser treatments. Clinical evaluations and optical coherence tomography (OCT) imaging were performed.

RESULTS

Thirteen subjects were enrolled. The mean age was 51.3 years, and 92.3% were women. Fitzpatrick skin types I–IV were included. Treatment indications included broken blood vessels, rosacea, port-wine birthmark, and spider angioma. For physician investigator grading, all subjects were graded as improved at both 30-day and 90-day follow-up. Blinded photographic review by 3 independent, blinded physicians had a mean of 89.7% of cases selected correctly with at least 2 of 3 in agreement for 100.0% of cases. Optical coherence tomography imaging showed significant reductions in vessel density (p = .018) and diameter (p = .003) of the superficial vascular plexus. No serious adverse events occurred.

CONCLUSION

A novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling can safely and effectively improve vascular conditions and lesions as determined by both clinical and OCT evaluation.

Vascular lesions—whether congenital or acquired—can have a significant impact on the psychosocial well-being and overall quality of life of patients. These contribute to a significant portion of cosmetic dermatology visits each year.^1,2 Over the years, laser therapy has emerged as the treatment of choice for many vascular lesions because of its ability to selectively target superficial vessels while minimizing undesired injury to surrounding tissue. With selective photothermolysis, laser therapy can target hemoglobin to safely heat the surrounding blood vessels and subsequently damage and destroy them.^3,4

The 585 and 595 nm pulsed dye laser (PDL) with cryogen spray cooling has established itself as a preferred laser modality for the treatment of vascular lesions, which can be attributed to its efficacy and safety profile.⁵ However, this modality can be limited by the depth of the vascular lesion especially because lesions thicker than 3 mm may exhibit reduced responsiveness.^6–8 The liquid dye medium of the PDL can limit the range of available settings and further lends itself to complexities with maintenance and reliable operation. Although the 1,064 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has demonstrated efficacy for deeper lesions, the contact cooling approach that is often used can limit its utility and increase the risk of dyspigmentation.^9–11

To address certain limitations, a novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling (DermaV, Lutronic, South Korea) was recently developed. This high-power laser combines multiple wavelengths with large spot sizes in a single device, thereby allowing for greater versatility in treating vascular lesions of varying characteristics, including size, depth, and vascular features.¹¹ This laser offers different pulse modes ranging from sub-microsecond pulses to sub-millisecond pulses up to a single continuous pulse, which may offer increased options and versatility when treating complex vascular lesions. The cryogen spray cooling system enables pre-laser and post-laser spray cooling, which offers protective benefits to the surrounding and overlying skin to minimize discomfort and increase safety during the treatment.¹⁰ Although a previous study has demonstrated the ability of this laser to improve the clinical appearance of various vascular and pigmented lesions, its specific impact on the underlying vascular morphology remains unknown.¹¹ Optical coherence tomography (OCT) is a noninvasive imaging modality that can evaluate the underlying structures within the skin and can assess vascular morphology. Its application in conjunction with the treatment effects from this laser has not yet been explored.

In this study, we evaluated the safety and efficacy of this novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling for the treatment of vascular lesions, using both clinical data and OCT imaging. Through this integrated approach, we objectively assess improvements in clinical appearance and vascular morphology, to provide further insights into the treatment of vascular lesions.

Materials and Methods

Thirteen healthy subjects with vascular conditions and lesions were enrolled. This study was approved by an independent IRB. Informed consent was obtained from all subjects. To be included, subjects had to be older than 18 years with a vascular condition or lesion suitable for laser treatment. Subjects were excluded if they had metabolic disorders, such as porphyria and other light-induced rashes; history of keloids or poor wound healing; significant scarring in the area; open wounds in the area; tattoos in the area; excessive dermatochalasis, deep dermal scarring, or thick sebaceous skin in the area; history of condition and/or medication use that can cause photosensitivity; history of autoimmune disease; inability to refrain from artificial tanning, including the use of tanning booths; history of surgical or cosmetic treatments in the area within the past year; and history or current use of systemic retinoids within the past year, topical retinoids within the past 2 weeks, and/or antiplatelet agents or anticoagulants.

Each subject received treatments with a novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling (DermaV, Lutronic, South Korea). Treatment parameters were selected at physician discretion and were based on early clinical results, physician experience, and live clinical endpoints during the treatment. Settings were recorded at each treatment visit. Subjects were allowed to receive up to 9 treatments per physician discretion with treatment intervals ranging between 2 and 8 weeks, and follow-up visits occurred at 1 and 3 months after the last treatment. Subjects did not receive other treatments for the vascular conditions or lesions during the study, and treatment was limited to the affected areas.

At treatment and follow-up visits, standardized photographs were taken of the treatment area. In addition, images were taken using an OCT scanner (VivoSight, Michelson Diagnostics, United Kingdom) to capture noninvasive, in vivo imaging of the vascular lesions or a representative area of the vascular condition. This OCT scanner uses a low-power 1,300 nm laser with multibeam swept source frequency domain processing. It can provide <7.5 μm resolution within a 6 × 6 mm field of view, and penetration can reach up to 1 to 2 mm of depth. The depth of the top portion of the superficial vascular plexus is estimated as the depth at which the vessel density reaches 50% of the maximum. Vessel diameter and density were calculated as the averages of the top 100 μm of the vascular plexus. This was performed by incorporated software algorithms.

At follow-up visits, physician investigators were instructed to grade clinical improvement using a 5-point Global Aesthetic Improvement Scale (GAIS) (1: Very much improved; 2: Much improved; 3: Improved; 4: No change; and 5: Worsened). Three blinded physician reviewers were also provided with sets of before and after photographs from baseline and follow-up visit. They were instructed to select the correct before and after photograph as well as grade the clinical improvement using a different 5-point GAIS (1: Poor, 0%–24% improvement; 2: Fair, 25%–49% improvement; 3: Good, 50%–74% improvement; 4: Excellent, 75%–94% improvement; and 5: Complete, 95%–100% improvement). Responder status was defined as at least 2 of the 3 blinded physician reviewers selecting the correct photographs. Safety data and adverse events were recorded throughout the study.

Results

A total of 13 subjects underwent treatment with the novel, variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling and had sufficiently evaluable photographs and OCT images available for review. The mean age was 51.3 years (R: 31–71 years). Of all subjects, 92.3% (n = 12) were women. For Fitzpatrick skin type, 30.8% (n = 4) were Type I, 23.1% (n = 3) were Type II, 38.5% (n = 5) were Type III, and 7.7% (n = 1) were Type IV.

Treatment indications included broken blood vessels (53.8%, n = 7), rosacea (23.1%, n = 3), port-wine birthmark (15.4%, n = 2), and broken blood vessels and spider angioma (7.7%, n = 1). Locations included the face (84.6%, n = 11), back (7.7%, n = 1), and lower extremity (7.7%, n = 1). Subjects had a mean of 4.9 treatments (R: 3–6 treatments). Median treatment interval was 21 days.

All subjects (n = 13) were treated using the 532 nm wavelength. Subjects were treated using either the sub-microsecond (7.7%; n = 1) pulse mode, sub-millisecond (15.4%; n = 2) pulse mode, or a combination of both (76.9%; n = 10). For the sub-microsecond pulse mode, mean spot size was 9.2 mm (R: 6–13 mm), mean fluence was 8.5 J/cm² (R: 5.5–13 J/cm²), and mean pulse duration was 10.4 ms (R: 6–15 ms). For the sub-millisecond pulse mode, mean spot size was 8.7 mm (R: 8–12 mm), mean fluence was 10.8 J/cm² (R: 6.5–17 J/cm²), and mean pulse duration was 12.2 ms (R: 8–28 ms).

For physician investigator grading, all (100.0%) subjects were graded as improved at both follow-up visits. At 30-day follow-up, 76.9% of subjects were rated as either very much improved or much improved (4 or 5, out of 5), which increased to 90.9% of evaluable subjects at 90-day follow-up.

Blinded photographic review was performed by 3 independent, blinded, physician reviewers. The correct before and after photograph was selected in 100.0%, 92.3%, and 76.9% of cases by the blinded reviewers, respectively, for a mean of 89.7% of cases selected correctly. Overall, at least 2 of the 3 blinded reviewers were in agreement in selecting the correct photographs in 100.0% of cases, translating to a responder rate of 100.0%. When assessing blinded reviewer GAIS, mean scores were 4.0, 3.5, and 3.4 out of 5 by the blinded reviewers for an overall mean of 3.6. This was between “3: Good, 50%-74% improvement” and “4: Excellent, 75%-94% improvement.”

For OCT imaging, superficial vascular plexus depth, density, and diameter were calculated by incorporated software algorithms. Earliest and latest sufficiently evaluable OCT images and analyses were used to evaluate treatment effects on the vascularity of the conditions and lesions being treated. After the treatment course, there were significant reductions in vessel density (20.5% vs 13.7%; p = .018) and vessel diameter (139.2 vs 70.8 μm; p = .003). There was no significant change in superficial vascular plexus depth (233.9 vs 243.8 μm).

During the study, only expected treatment effects were observed, which included transient erythema and transient edema. All were mild and resolved without any medical intervention. No serious adverse events occurred, including necrosis and scarring.

Discussion

This study combines clinical grading with OCT imaging to assess the efficacy and safety of treating vascular conditions and lesions using this variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling. We demonstrate how this high-power laser can significantly improve the clinical appearance of lesions, as well as impact the superficial vascular plexus depth, density, and diameter (Figures 1–3).

Figure 1.

Male subject at baseline (left) and at follow-up (right) with decrease in superficial vessel density from 31.0% to 4.4% after 3 treatments. Clinical photograph on top with corresponding optical coherence tomography (OCT) imaging on bottom.

Figure 3.

Female subject at baseline (left) and at follow-up (right) with decrease in superficial vessel density from 31.0% to 16.0% after 3 treatments. Clinical photograph on top with corresponding optical coherence tomography (OCT) imaging on bottom.

Figure 2.

Female subject at baseline (left) and at follow-up (right) with decrease in superficial vessel density from 8.6% to 4.1% after 2 treatments. Clinical photograph on top with corresponding optical coherence tomography (OCT) imaging on bottom.

This laser can provide several advantages for the treatment of vascular lesions. The integration of multiple wavelengths and large spot sizes within a single device enables physicians to customize treatment parameters based on the specific characteristics and morphology of the vascular lesion to optimize individual patient outcomes.¹¹ The built-in cryogen cooling spray offers protection to the surrounding skin to minimize the risk of undesired thermal damage and reduce discomfort during the treatment.¹⁰ With the addition of contact-based, speed-sensing technology in an optional rolling handpiece, the device can monitor the movement and speed of the handpiece in real-time to ensure consistent and uniform delivery of laser energy.¹¹ This can be especially helpful for larger treatment areas.

This study demonstrates that this laser is effective at treating vascular lesions in a variety of skin types because the cohort included those with Fitzpatrick skin types I–IV. Subjects also experienced clinical improvement in an average of 5 treatments for various lesions. Our study additionally reveals improvement in lesion appearance for several months after treatment, as evidenced by the high percentage of subjects who were graded as either very much improved or much improved (4 or 5, on a scale of 5) by the 30-day (76.9%) and 90-day (90.9%) follow-up visits. The increase may be due to further clearance of the damaged vessels, stimulation of collagen production, increased cell turnover, and continued remodeling. The high degree of improvement at 90-day follow-up demonstrates the durability of the treatment. The significant results in clinical improvement among both physician investigators and blinded physician reviewers mitigated the potential for performance bias. Finally, there were no severe adverse events, which further shows the safety profile of this device.

In addition to evaluating clinical improvement, our study used OCT imaging to assess changes in vascular morphology after treatment with the variable-sequenced, long-pulsed, 532 and 1,064 nm laser with cryogen spray cooling. Optical coherence tomography, a noninvasive imaging technique, captures high-resolution, cross-sectional images of structures within the skin.^3,12 Its introduction into the field has enhanced diagnostic accuracy, treatment planning, and monitoring of dermal structures.¹³ Subsequent research has demonstrated the utility of OCT in assessing various dermatologic conditions, including nonmelanoma skin cancers, pigmented lesions, inflammatory skin diseases, and nail disorders, as well as treatment effects from lasers and energy-based devices.^14,15 More recently, OCT imaging has emerged as a valuable tool for evaluating and managing vascular lesions, providing visualization of vascular depth, diameter, and density within the superficial vascular plexus.^3,16–18

Our study provides evidence that not only validates the ability of OCT imaging to evaluate superficial vascular morphology but also demonstrates the effectiveness of this high-power laser in treating vascular lesions. Through precise quantitative assessment using OCT imaging, we successfully demonstrate a significant reduction in both superficial vessel density and diameter after laser treatment, which likely helps to explain the substantial improvements seen in the clinical appearance of the vascular lesions.

While acknowledging the limitations of a smaller sample size, our study provides compelling evidence of the efficacy and safety of the variable-sequenced, long-pulsed, 532 and 1,064 nm laser in treating superficial vascular lesions. Larger prospective studies with a diverse patient population are warranted. In addition, it is important to acknowledge the potential influence of confounding variables, such as age, sex, comorbidities, room temperature, and patient positioning on OCT measurements.^18,19 Future investigations should carefully consider these variables to ensure understanding of their impact on treatment outcomes.

Conclusion

Using both clinical assessment and OCT imaging technology, the novel variable-sequenced, long-pulsed, 532 nm and 1064 nm laser with cryogen spray cooling was shown to be effective and safe. The laser demonstrated significant success in improving not only the clinical appearance of vascular lesions but also the morphology of the underlying superficial vessels.