The impact of temperature on vascular function in connection with vascular laser treatment.

Pulsed dye lasers are used effectively in the treatment of psoriasis with long remission time and limited side effects. It is, however, not completely understood which biological processes underlie its favorable outcome. Pulsed dye laser treatment at 585-595 nm targets hemoglobin in the blood, inducing local hyperthermia in surrounding blood vessels and adjacent tissues. While the impact of destructive temperatures on blood vessels has been well studied, the effects of lower temperatures on the function of several cell types within the blood vessel wall and its periphery are not known. The aim of our study is to assess the functionality of isolated blood vessels after exposure to moderate hyperthermia (45 to 60°C) by evaluating the function of endothelial cells, smooth muscle cells, and vascular nerves. We measured blood vessel functionality of rat mesenteric arteries (n=19) by measuring vascular contraction and relaxation before and after heating vessels in a wire myograph. To this end, we elicited vascular contraction by addition of either high potassium solution or the thromboxane analogue U46619 to stimulate smooth muscle cells, and electrical field stimulation (EFS) to stimulate nerves. For measurement of endothelium-dependent relaxation, we used methacholine. Each vessel was exposed to one temperature in the range of 45-60°C for 30 seconds and a relative change in functional response after hyperthermia was determined by comparison with the response per stimulus before heating. Non-linear regression was used to fit our dataset to obtain the temperature needed to reduce blood vessel function by 50% (Half maximal effective temperature, ET50). Our findings demonstrate a substantial decrease in relative functional response for all three cell types following exposure to 55°C-60°C. There was no significant difference between the ET50 values of the different cell types, which was between 55.9°C and 56.9°C (P>0.05). Our data show that blood vessel functionality decreases significantly when exposed to temperatures between 55°C-60°C for 30 seconds. The results show functionality of endothelial cells, smooth muscle cells, and vascular nerves is similarly impaired. These results help to understand the biological effects of hyperthermia and may aid in tailoring laser and light strategies for selective photothermolysis that contribute to disease modification of psoriasis after pulsed dye laser treatment.

532-nm potassium titanyl-phosphate laser versus 595-nm pulsed dye laser for port-wine birthmarks: A prospective, randomized, split-side study.

BACKGROUND: Pulsed dye lasers (PDL) are currently the first-line treatment of port-wine birthmarks (PWB). Due to high maintenance costs and instable technology, alternative methods are needed. OBJECTIVES: To compare clinical outcomes of a variable-sequenced, long-pulsed 532-nm potassium titanyl-phosphate (KTP) laser and PDL on treating PWB. METHODS: A prospective, randomized, split-side study. Patients were treated with a KTP laser and PDL with 1 to 5 sessions at intervals of 6-8 weeks. A follow-up visit was scheduled 6 weeks post-treatment. Efficacy was evaluated through colorimetric analysis, area reduction measurements and clinical evaluations by two blinded investigators based on photo documentation. Subjects provided rating of pain intensity during treatment, post-treatment reactions and satisfaction. Safety was measured by adverse events. Maintenance issues of the laser systems were documented. RESULTS: A total of 35 patients (mean age 42.1 years) were enrolled. 63% were female. Patients received 2.4 (SD 1.4; 1-5) treatment sessions. Colorimetric analysis indicated a comparable clearance effect in PWB of both KTP laser and PDL. Independent investigators rated clinical appearance to be significantly improved compared to baseline. No significant difference was observed between both laser systems. Regarding post-treatment reactions, the KTP laser caused less swelling, purpura and crusts. 96% would recommend both treatment modalities. Patients were satisfied with both laser systems. During the study, PDL systems malfunctioned for 6.6 months in total. For the KTP laser, we did not observe any system failures. CONCLUSION: Our data indicate that the KTP laser of the latest generation with large-spot sizes, subpulse technology and cryogen cooling has a comparable efficacy to the PDL in treating PWB. In addition, KTP laser is associated with greater tolerability, fewer technical failures and lower repair costs. Further prospective studies are required to determine the true effectiveness of the KTP laser in PWB treatment. This study was preregistered in Clinicaltrials.gov (NCT05771298).

Fragile hands: targeting nonmelanoma skin cancer on older hands using 595 nm pulsed dye laser.

PURPOSE: The mainstay of treatment for nonmelanoma skin cancer (NMSC) on thin skin remains surgical, but procedures on older hands may be complicated by skin fragility and dermal atrophy. Used without cooling, 595 nm (nm) pulsed dye laser (PDL) has the capability of destroying NMSC through nonspecific thermal necrosis. The purpose of this study was to understand recurrence of NMSC on dorsal hands of older patients after one or two treatments using 595 nm PDL. METHODS: A retrospective chart review identified 147 cases of NMSC located on the dorsal hands treated with 595 nm PDL. Cases of basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) were included. All patients received one to two treatments with PDL. The primary outcome was the recurrence of carcinoma. RESULTS: Among NMSC cases treated with PDL, recurrence occurred in 12 patients (8.2%). No cases of BCC recurred during the study period. Recurrence of SCC was 4.7% for SCC in situ and 10.4% recurrence for invasive SCC (p = 0.34). Among 71 patients treated once, recurrence occurred in 10 patients (14.1%), and among 76 cases treated twice, recurrence occurred in 2 patients (2.6%, p = 0.01). CONCLUSION: Two treatments of PDL for NMSC on the dorsal hands of older patients was well tolerated, had low recurrence, and seemed more effective than one treatment.

Current clinical evidence is insufficient to support HMME-PDT as the first choice of treatment for young children with port wine birthmarks.

BACKGROUND: Port wine birthmark (PWB) is a congenital vascular malformation of the skin. Pulsed dye laser (PDL) is the "gold standard" for the treatment of PWB globally. Hematoporphyrin monomethyl ether (HMME or hemoporfin)-mediated photodynamic therapy (HMME-PDT) has emerged as the first choice for PWB treatment, particularly for young children, in many major hospitals in China during the past several decades. AIM: To evaluate whether HMME-PDT is superior to PDL by comparing the clinical efficacies of both modalities. METHOD: PubMed records were searched for all relevant studies of PWB treatment using PDL (1988-2023) or HMME-PDT (2007-2023). Patient characteristics and clinical efficacies were extracted. Studies with a quartile percentage clearance or similar scale were included. A mean color clearance index (CI) per study was calculated and compared among groups. An overall CI (C0), with data weighted by cohort size, was used to evaluate the final efficacy for each modality. RESULT: A total of 18 HMME-PDT studies with 3910 patients in China were eligible for inclusion in this analysis. Similarly, 40 PDL studies with 5094 patients from nine different countries were eligible for inclusion in this analysis. Over 58% of patients in the HMME-PDT studies were minors (<18 years old). A significant portion (21.3%) were young children (<3 years old). Similarly, 33.2% of patients in the PDL studies were minors. A small proportion (9.3%) was young children. The overall clearance rates for PDL were slightly, but not significantly, higher than those for HMME-PDT in cohorts with patients of all ages (C0, 0.54 vs. 0.48, p = 0.733), subpopulations with only minors (C0, 0.54 vs. 0.46, p = 0.714), and young children (C0, 0.67 vs. 0.50, p = 0.081). Regrettably, there was a lack of long-term data on follow-up evaluations for efficacy and impact of HMME-PDT on young children in general, and central nervous system development in particular, because their blood-brain barriers have a greater permeability as compared to adults. CONCLUSION: PDL shows overall albeit insignificantly higher clearance rates than HMME-PDT in patients of all ages; particularly statistical significance is nearly achieved in young children. Collectively, current evidence is insufficient to support HMME-PDT as the first choice of treatment of PWBs in young children given: (1) overall inferior efficacy as compared to PDL; (2) risk of off-target exposure to meningeal vasculature during the procedure; (3) administration of steriods for mitigation of side effects; -and (4) lack of long-term data on the potential impact of HMME on central nervous system development in young children.

Treatment of erythematous acne scars using 595-nm pulsed dye laser combined with 1565-nm ResurFX nonablative fractional laser.

BACKGROUND: Acne vulgaris is a common inflammatory disease associated with various sequelae after skin lesion remission. Acne erythema has been considered simple erythema or a vascular lesion; however, because the understanding of this disease has improved, acne erythema is currently considered an early scar with erythematous components. AIMS: This study evaluated the efficacy of using both a 595-nm pulsed dye laser (PDL) and 1565-nm nonablative fractional laser (NAFL) for the treatment of erythematous scars caused by acne. METHODS: Ninety patients with acne scars were equally randomized to two groups. Group A (n = 45) received treatment with the NAFL. Group B (n = 45) received treatment with the PDL and NAFL. Each patient underwent one treatment session and 4 weeks of follow-up. RESULTS: Qualitative (χ2 = 12.415; p < 0.05) and quantitative (t = 2.675; p < 0.05) scores of Groups A and B were determined using a global scarring grading system and exhibited statistically significant differences. The quantitative score of Group A was higher than that of Group B (6.67 ± 3.46 vs. 4.98 ± 2.44). The erythema areas of the groups differed significantly after treatment, with Group B exhibiting more notable score improvements (5.00 [3.10, 7.10] vs. 2.80 [1.65, 4.60]; Z = 3.072; p < 0.05). The erythema regression rate of Group B (88.9%) was significantly higher than that of Group A (66.7%) (χ2 = 20.295; p < 0.001). Adverse events, including redness and swelling (86.6%), scabbing (78.8%), and purpura (36.6%), occurred within 7 days for 86.6% of patients. CONCLUSIONS: The combined use of the PDL and NAFL is safe and effective for erythematous acne scars.

A 595 nm pulsed dye laser as an adjuvant intervention for post-comedone extraction erythema and comedone reduction: A randomized, split-face controlled trial.

BACKGROUND: Comedone extraction provides greater satisfaction for acne treatment than conventional treatment alone; however, post-comedone extraction erythema (PCEE) remains a concern for patients. OBJECTIVES: To evaluate the efficacy of pulsed-dye laser (PDL) in PCEE and comedone reduction. METHODS: Mild-to-moderate acne patients were randomly allocated in split-face fashion. Three comedones were extracted on each facial side. On the PDL-treated side, 595-nm PDL was delivered to the entire side with an additional shot on three comedone-extracted sites. Erythema index (EI) and total acne lesion counts (TALC) were evaluated at baseline, week 2 and 4. The comprehensive acne severity scale (CASS) was assessed by three blinded independent pediatric dermatologists. Participant satisfaction surveys were completed at the end of the study. RESULTS: Thirty-five participants (age 12.9-24.2 years) showed no differences in the EI and TALC at baseline on both sides. At weeks 2 and 4, the EI on the PDL-treated side was significantly lower (p < 0.001) with a greater EI reduction (p < 0.001) when compared to the control side regardless of gender and menstruation. There was significantly lower TALC on the PDL-treated side at week 2 (p < 0.001) and week 4 (p = 0.02). No complications were noted with high participant satisfaction reported (median 8; IQR 7-9). PDL remained significantly associated with EI improvements after controlling for gender, menstruation cycle, and examination stress. CONCLUSION: PDL can be an adjunctive intervention for the treatment of PCEE and comedone reduction due to its effectiveness and high participant satisfaction.

Successful treatment of xanthoma disseminatum with pulsed dye laser: A case report.

Xanthoma disseminatum is a rare form of non-Langerhans cell histiocytosis with limited treatment options due to its unknown aetiology and diffuse skin lesions. This case report presents the successful treatment of a 31-year-old male with severe pan-facial xanthoma disseminatum lesions following a facial burn and traumatic brain injury resulting from a car accident. After 5 sessions of monthly pulsed dye laser treatment, there was a clinically significant reduction in the lesions. Over the course of 3 years, the patient underwent a series of monthly pulsed dye laser treatments, and the lesions were almost cleared. These findings suggest that pulsed dye laser therapy may offer an effective treatment option for managing xanthoma disseminatum. This is the first report on use of the pulsed dye laser for treatment of xanthoma disseminatum.

Pulsed dye laser and adjuvant topical therapies for the treatment of port-wine stains: A systematic review.

OBJECTIVES: The current gold standard treatment for port-wine stains (PWS) is pulsed dye laser (PDL). However, multiple treatment sessions may be necessary and complete resolution is often not achieved. Neoangiogenesis can occur soon after treatment and is thought to be a major factor contributing to treatment failure. Adjuvant antiangiogenic topical therapies may therefore improve the efficacy of pulsed dye laser treatment of port-wine stains. MATERIAL AND METHODS: Following PRISMA guidelines, we searched PubMed, Embase, Web of Science, and clinicaltrials.gov using "port-wine stain," "nevus flammeus," "capillary malformation," "sturge weber," and "pulsed dye laser" as keywords and medical subject heading (MeSH) terms. Articles were included if they (1) were a randomized controlled trial (RCT); (2) studied patients with PWS; and (3) investigated topical adjuvant therapies with PDL. Bias was assessed using the Critical Appraisal Skills Programme (CASP) Randomized Controlled Trial Standard Checklist. RESULTS: 1835 studies were identified, with six studies meeting inclusion criteria. The total number of patients studied was 103 (range: 9-23), with 8-36 week follow-up. The average age ranged from 11 to 33.5 years old. Three studies examined adjuvant topical sirolimus (n = 52), two examined timolol (n = 29), and one studied imiquimod (n = 22). Two of three RCTs reported no improvement through colorimetric analysis with topical sirolimus; however, one of these studies did show a significant improvement through Investigator Global Assessment (IGA) score. The last sirolimus study showed significant improvement through digital photographic image scoring (DPIA). Studies examining topical timolol reported no change in PWS appearance compared to placebo. The addition of 5% adjuvant imiquimod cream did lead to significant improvement. A variety of outcome measures were used. Imiquimod and sirolimus led to mild cutaneous adverse events, while timolol caused no side effects. None of the adverse events led to treatment discontinuation. Study quality was moderate in three, high in two, and low in one. CONCLUSION: The efficacy of adjuvant topical therapy was unclear. Limitations included variation in concentration and duration of adjuvant therapies, differences in follow-up time, and inconsistent outcome measure reporting. Given their potential clinical promise, larger prospective studies examining topical adjuvant therapies should be considered.

Treatment of Ecchymosis with a Pulsed Dye Laser.

Ecchymosis is a common side effect after injury and surgery. A pulsed dye laser (PDL) is the gold standard for vascular lesions and can minimize ecchymosis. Heating induces hemoglobin modification due to oxidative and heat reactions with the formation of bilirubin and methemoglobin, resulting in color changes to brown-yellow. Therefore, downtime following cosmetic procedures can be shortened.

Assessment of the efficacy of 595 nm pulsed dye laser in the management of facial flat angiomas. Results of a case series.

BACKGROUND: Studies on pulsed dye laser (PDL) have shown the best efficacy and safety data for treating vascular anomalies among the various lasers used and the 595-nm PDL has been used to treat cutaneous vascular anomalies for about 30 years. The purpose of this study was to assess the efficacy of 595 nm Pulsed Dye Laser in the management of facial flat angiomas present in the form of Port-Wine Stain. MATERIALS AND METHODS: Seven cases of PWS in Fitzpatrick skin type ranged from I to III and colour ranging from pink to purple, were treated with 595 nm pulse Dye Laser. Patients underwent to 6-8 laser sessions at 20-30 days intervals. Results obtained were judged by dermatologist, by comparing pre-treatment and post-treatment photographs, 6 months after the last session and a quartile scale of lesion clearance (4-point Investigator Global Assessment scale): 1 = no or low results (0%-25% of the lesion area improved), 2 = slight improvement (25%-50% of the lesion area cleared), 3 = moderate-good improvement (50%-75%), and 4 = excellent improvement (75%-100%) was used. Possible side effects such as blisters, hyper/hypopigmentation, and scarring were monitored. RESULTS: All patients observed global improvements. 71% of patients achieved excellent clearance and 29% patients achieved good-moderate clearance of their angioma. Patients were asked for a subjective evaluation of the results: 57% of patients were very satisfied, 29% were satisfied, and 14% patients were not very satisfied with the results. No patients were dissatisfied. No significant side effects were noted. CONCLUSION: This research confirms the efficacy of the 595 nm PDL for flat angioma management, without considerable side effects.

A retrospective 10 years- experience overview of dye laser treatments for vascular pathologies.

INTRODUCTION: The Flash-lamp pulsed dye laser (FPDL) is nowadays considered the most precise laser currently on the market for treating superficial vascular lesions. In this study, we gathered data from 10 years of experience regarding dye laser treatment of patients presenting vascular malformations such as telangiectasia, rhinophyma, port-wine stain, cherry and spider angioma and vascular tumours. METHODS: Subjects were enrolled from 2013 to 2023 based on the vascular anomalies they presented. They underwent different treatment sessions with the FPDL device. RESULTS: The age-range distribution by vascular anomaly confirmed that haemangiomas are typical in children while rhinophyma is a condition very common in older adults. A difference in sex distribution showed that pathologies such as telangiectasias typically affect women whereas rhinophyma is more frequent in men. Most of the treatments interested the face area but no permanent side effects were registered. CONCLUSIONS: Our 10 years of experience with FPDL demonstrated good results in a wide range of applications for the treatment of different vascular anomalies. The absence of long-term side effects and bearable pain during the treatment makes it a valuable solution for the resolution of benign tumours also in very young patients.

Comparative effectiveness among available treatments in difficult-to-treat port-wine stains (PWS): a Network Meta-Analysis of observational evidence.

BACKGROUND: Although pulsed dye laser (PDL) is the treatment of choice for port-wine stains (PWS), clinical resistance to PDL has been observed in 20-30% of cases. Several alternative treatment modalities have been introduced; however, there is still a lack of definite recommendations regarding the optimal treatment for difficult-to-treat PWS. OBJECTIVE: We aimed to systematically review and analyze the comparative effectiveness among treatments for problematic PWS. METHODS & MATERIALS: We systematically searched for comparative studies assessing treatments for patients with difficult-to-treat PWS through relevant biomedical databases until August 2022. A Network Meta-Analysis (NMA) was conducted to estimate the odds ratio (OR) for all pairwise comparisons. The primary outcome is the improvement of lesions of more than 25%. RESULTS: Of the 2498 studies identified, six treatments from five studies were available for NMA. Compared with 585 nm short-pulsed dye laser (SPDL), intense pulsed light (IPL) was the most effective in clearing lesions (OR 11.81, 95% CI 2.15 to 64.89, very low confidence rating), followed by 585 nm long-pulsed dye laser (LPDL) (OR 9.95, 95% CI 1.75 to 56.62, very low confidence rating). The 1064 nm NdYAG, 532 nm NdYAG, and LPDL >585 nm exhibited potential superiority over SPDL 585 nm, although statistical significance was not observed. CONCLUSIONS: IPL and 585 nm LPDL are likely to be more effective than 585 nm SPDL for treating difficult-to-treat PWS. Well-designed clinical trials are warranted to confirm our findings.

Largest comparative analysis: Novel large spot size 595 nm, high-energy, pulsed dye laser reduces number of treatments for improvement of adult and pediatric port wine birthmarks.

OBJECTIVE: Port wine birthmarks (PWBs) are vascular malformations affecting 0.3%-0.5% of newborns with the tendency to persist into adulthood without adequate treatment of the heterogenous ectatic vessels. This study compares treatment outcomes and parameters of the prior generation pulsed dye laser (PPDL) and the larger spot novel generation pulsed dye laser (NPDL) to establish whether a larger spot size laser provides greater clearance with fewer treatments. METHODS: One hundred and sixty patients were treated with either the PPDL (80 patients) and NPDL (80 patients) with retrospective review of age, body site, laser treatment parameters, number of treatments, and improvement following laser therapy. RESULTS: Patients treated with PPDL were older on average than patients treated with NPDL (mean 24.8 ± 19.7 vs. mean 17.1± 19.3 years, p < 0.05). The majority of lesions treated with PPDL were located on the face and neck, whereas truncal and extremity sites were more frequently treated with the NPDL. Use of NPDL was associated with a mean maximum spot size of 13.1 mm and mean maximum fluence of 7.3 J/cm2 with pulse durations of 0.45-3 ms, whereas use of the PPDL was associated with a mean spot size of 10.8 mm and mean maximum fluence of 8.8 J/cm2 with pulse durations of 0.45-6 ms. Fifty percent improvement was seen with 8.8 PPDL treatments compared to 4.3 NPDL treatments (p ≤ 0.01) with no significant difference in overall mean improvement between both devices at the chosen parameters. Multiple regression analysis showed that device type, not age or lesion location, was the only statistically significant independent variable to affect the endpoint of at least 50% improvement of the lesion. CONCLUSIONS: Use of the larger spot NPDL is associated with achieving 50% improvement with fewer treatments.