Histological and Immunofluorescent Analysis of a Large Tributary of the Great Saphenous Vein Treated with a 1920 nm Endovenous Laser: Preliminary Findings

Third generation of laser (>1900) for endovenous thermoablation (EVLA) of varicose veins: A systematic review and meta-analysis

OBJECTIVES

Third generation lasers with longer wavelengths (>1900 nm) have been introduced, in recent years, for the treatment of varicose veins. The possible advantage of the new generation lasers is that they allow complete damage to the vein wall using a lower Power in Watts (W: J/sec) and a lower linear energy density (LEED: J/cm). The aim of this work is to evaluate the results present in the literature regarding efficacy and safeness of the new generation lasers for the treatment of varicose veins.

METHODS

Published articles were searched on PubMed database and on Cochrane Library, entering the keywords "1940 nm or 1920 nm laser AND varicose veins laser thermoablation (EVLA)." The primary endpoint of the study was to value rate of occlusion and adverse events at the short term follow-up. The search yielded a total of 14 studies. In the end, only six studies were judge eligibility.

RESULTS

The studies were heterogenous in their documentation, EVLA, duplex ultrasound protocol and result reporting. A total of 540 limbs of 377 patients were treated with endovenous laser ablation (EVLA) with laser 1920-1940 nm. The treated veins had a mean diameter of 0.74 ± 0.17 cm and a mean length of 27.87 ± 20.63 cm. The pooled estimates of immediate occlusion rate was of 99.8% (95% CI: 97.9% to 100.0) with high heterogeneity (I2 = 60%; 95% PI: 89.7% to 100%), while at short-term follow-up was of 98.2% (95% CI: 94.0% to 100.0%) with higher heterogeneity (I2:79%; 95% PI: 77.1% to 100.0%). EHIT occurred in 7 cases (pooled estimate: 0.7%). The other adverse events rate reported were 1% of hyperpigmentation, 2.8% of neurological complications, 0.6% thrombophlebitis and 1.9% of bruising/hematoma. The pooled mean estimates of LEED was equal to 38.2 J/cm (95% CI: 26.3 to 50.1 J/cm) although with a very large heterogeneity (I2 = 100%).

CONCLUSIONS

The overall success rate of EVLA was high. The analysis of these studies suggests that using lower parameters (Power and linear administered energy) may have no effect on the treatment success rate. Short-term results demonstrate comparable occlusion rates respect the second-generation lasers. Instead, data suggest a low complication rates. Short-term results demonstrate comparable complications rates respect the second-generation lasers (1300-1470 nm). Randomized studies with longer follow-up are required to evaluate the EVLA 1900 nm procedure further.

Endovenous laser ablation (EVLA) for vein insufficiency: two-year results of a multicenter experience with 1940-nm laser diode and a novel optical fiber

Thermoablative techniques currently represent, in accordance with international guidelines, the most used methods in the treatment of varicose veins. From some years, lasers with a wavelength greater than 1900 nm have been introduced for EndoVenous Laser Ablation (EVLA) treatment. However, currently, few clinical studies regarding this new technology are reported in the medical literature. The aim of this study is to evaluate outcomes at a 2-year follow-up (mid-term) of EVLA of varicose veins of the lower limbs using a 1940-nm laser and a new cylindric monoring fiber. This clinical trial was conducted as a multicenter, retrospective, non-randomized, non-blind clinical study. Ninety-three patients were enrolled for a total of one hundred consecutive procedures performed in the period between January 2021 and May 2021 in two Italian facilities. The primary efficacy endpoint was the occlusion rate of the treated vein immediately after surgery and at the follow-up (24 months). The secondary efficacy endpoint was the evaluation of the parameters of energy delivered during the procedure (power and linear energy density or LEED). The primary safety endpoints were the incidence of pain (1 day and 7 days after surgery) and the rate of intraoperative and postoperative complications. The precepted pain was evaluated with the visual analog scale (VAS). The secondary safety endpoint was the evaluation of the improvement of the patient's symptoms related to venous disease. This evaluation was conducted by recording the changes in clinical, etiologic, anatomic, and pathophysiologic (CEAP) classification. All procedures were carried out regularly on an outpatient basis, and no intraoperative complications occurred. The occlusion rate of the target veins was 100% at 7- and 30-day controls. At follow-up controls, performed at 6 months, 1 and 2 years carried out showed an occlusion rate respectively of 99% (97 to 100), 96.9% (93.6 to 100), and 95.9% (92.1 to 99.9). The secondary efficacy endpoint was the evaluation of the parameters of energy delivered during the procedure (power watt and linear energy density): As regards the power parameters, we report an average of watts of 4.5 ± 0.8 [2.5 to 6] and linear energy density delivered (LEED) of 41.2 ± 8.6 [(21.1 to 66.7)]. The pain reported (with VAS scale) on 1 day of the procedure was 2 [1; 3] and 1 [0 to 4] at 7 days. All patients showed improved symptoms related to venous disease, with reduction of the individual CEAP class to which they belong. This study demonstrates that EndoVascular Laser Ablation (EVLA) treatment of varicose veins with a wavelength > 1900 nm is safe and effective. The overall occlusion rate was high. The reported results suggest that using lower parameters, such as output power (watts) and LEED (linear energy density), do not reduce the success rate of the treatment when used over 35 J/cm.

Brazilian guidelines on chronic venous disease of the Brazilian Society of Angiology and Vascular Surgery

The Brazilian Society of Angiology and Vascular Surgery has set up a committee to provide new evidence-based recommendations for patient care associated with chronic venous insufficiency. Topics were divided in five groups: 1. Classification, 2. Diagnosis, 3. Conservative or non-invasive treatment, 4. Invasive treatment and 5. Treatment of small vessels. This last series is closely related to the activities of Brazilian angiologists and vascular surgeons, who are heavily involved in the treatment of small superficial veins. These guidelines are intended to assist in clinical decision-making for attending physicians and health managers. The decision to follow a guideline recommendation should be made by the responsible physician on a case-by-case basis taking into account the patient's specific condition, as well as local resources, regulations, laws, and clinical practice recommendations.

A randomized clinical trial to assess the impact of laser power with constant linear endovenous energy density on outcomes of endovenous laser ablation (SLEDGE trial)

OBJECTIVE

To date, conflicting evidence has been reported regarding the energy settings to use during endovenous laser ablation (EVLA). In the present study, we evaluated the outcomes of EVLA of the great saphenous veins (GSVs) using different power settings with the same linear endovenous energy density (LEED) of ∼70 J/cm.

METHODS

We performed a single-center, randomized, controlled noninferiority trial with a blinded outcome assessment of patients with varicose veins of the GSV who underwent EVLA with a wavelength of 1470 nm and a radial fiber. The patients were randomly assigned to three groups according to the energy setting: group 1, 5 W power and an automatic fiber traction speed of 0.7 mm/s (LEED, 71.4 J/cm); group 2, 7 W and 1.0 mm/s (LEED, 70 J/cm); and group 3, 10 W and 1.5 mm/s (LEED, 66.7 J/cm). The primary outcome was the rate of GSV occlusion at 6 months. The secondary outcomes were pain intensity along the target vein the next day and at 1 week and 2 months after EVLA, the necessity for analgesics, and the occurrence of significant complications.

RESULTS

From February 2017 to June 2020, 245 lower extremities of 203 patients were enrolled. Groups 1, 2, and 3 included 83, 79, and 83 limbs, respectively. At 6 months of follow-up, 214 lower extremities were examined with duplex ultrasound. GSV occlusion was observed in 72 of 72 limbs (100%; 95% confidence interval [CI], 100%-100%) in group 1 and 70 of 71 limbs (98.6%; 95% CI, 97%-100%) in groups 2 and 3 (P < .05 for noninferiority). No difference was found in the pain level, necessity for analgesics, or rate of any other complications.

CONCLUSIONS

The technical results, pain level, and complications of EVLA were not associated with the combination of energy power (5-10 W) and the speed of automatic fiber traction when a similar LEED of ∼70 J/cm was reached.

Feasibility and short-term complication rate of mechanochemical ablation for epifascial tributaries of incompetent great saphenous veins

OBJECTIVE

The aim of the present study was to investigate the occurrence of skin complications after mechanochemical ablation with the ClariVein device (Merit Medical, South Jordan, Utah) for incompetent great saphenous veins (GSVs) and compare the results in terms of the target vein characteristics, especially in the presence of an epifascial GSV tributary.

METHODS

A single-center, retrospective study was performed. We reviewed 33 limbs of 32 patients with GSV insufficiency who had undergone mechanochemical ablation with the ClariVein device from December 2017 to February 2020. The 33 limbs were divided into two groups: the epifascial group, comprising 11 limbs of 11 patients, and the nonepifascial group, comprising 22 limbs of 21 patients. The patients underwent postoperative follow-up examinations at 1 week and 1, 3, 6, and 12 months. The skin complication counts and scores on a four-point scale were recorded.

RESULTS

Regarding the baseline characteristics, the epifascial group showed a significantly lower GSV depth in the distal thigh region compared with the nonepifascial group (2.64 ± 0.5 mm vs 7.05 ± 2.57 mm; P < .001). No statistically significant difference was found between the two groups in terms of the sclerosant (sodium tetradecyl sulfate) volume (5.45 ± 2.02 mL vs 6.59 ± 1.79 mL; P = .109) or ablation length (31.82 ± 3.92 cm vs 32.95 ± 4.05 cm; P = .449). All ClariVein procedures were technically successful (33 of 33 limbs; 100%), and no major complications were reported. The hyperpigmentation score was significantly greater in the epifascial group than in the nonepifascial group (score, 0.18 ± 0.4 vs 0 ± 0; P = .0401), although the hyperpigmentation count was not significantly different between the two groups (2 of 11 limbs [18.2%] vs 0 of 22 limbs [0.0%]; P = .1042). Although marginally higher counts and scores were observed in terms of phlebitis and bruising in the epifascial group, these differences were not statistically significant.

CONCLUSIONS

Endovenous treatment with the ClariVein device for incompetent GSVs can be performed safely. However, caution should be exercised when the epifascial GSV tributary is treated during the ClariVein procedure because of its predilection to result in hyperpigmentation.

Histopathologic differences in the endovenous laser ablation between jacketed and radial fibers, in an ex vivo dominant extrafascial tributary of the great saphenous vein in an in vitro model, using histology and immunohistochemistry

OBJECTIVE

The study aimed to investigate the biologic effects of the 1470-nm endovenous laser (EVL), with a jacketed fiber and a radial fiber, during EVL ablation of an ex vivo dominant extrafascial tributary of the great saphenous vein in our in vitro model by histology and immunohistochemistry.

METHODS

Ten segments of the dominant extrafascial tributary of the great saphenous vein were harvested by a consultant vascular surgeon from patients during routine varicose vein surgery. Six segments were treated using an ex vivo model of our design by a 1470-nm EVL with a jacketed fiber. The other four segments were also treated by a 1470-nm EVL but with a radial-firing fiber. Each segment was split into five sections and treated at five different linear endovenous energy densities (LEEDs) at 10 W: 0, 20, 40, 60, and 80 J/cm. The veins were incubated and subsections collected at 6 and 24 hours after treatment. Subsections were immersed in buffered formalin and taken for histologic and immunohistochemical analysis. Histopathologic analysis was then performed.

RESULTS

Treatment with the radial fiber led to a pattern of damage that was more homogeneous than with the jacketed fiber, with no carbonization of tissue present. Significant transmural damage and necrosis were observed at LEEDs of 60 and 80 J/cm in both treatment groups. At the same LEEDs, p53 and caspase 3 analysis showed that transmural cell wall vein death (necrosis or apoptosis) occurred by 6 hours after treatment with both fibers.

CONCLUSIONS

There was a significant difference in the effects of treatment with a jacketed fiber and a radial fiber in EVL ablation in vitro. Although both fibers caused transmural vein wall cell death at similar LEEDs, the pattern of damage with the radial fiber was more homogeneous. There was no overtreatment of tissue in terms of carbonization after treatment with the radial fiber. Treatment with the jacketed fiber showed carbonization of tissue at the same LEEDs.

Optimization of endovenous laser coagulation: in vivo experiments

Finding optimal parameters of endovenous laser coagulation using the radiation with a wavelength of 1910 nm. In vivo experiments have been carried out on the small saphenous veins of three sheep of Edilbay breed and the dependence of venous wall and surrounding tissue damage on the radiation power was analyzed on the basis of morphological study results, as well as ultrasound examination and clinical observation of animals in the postoperative period. As radiation source, we used the diode-pumped solid-state laser, based on the LiYF₄:Tm crystal, with emission wavelength of 1910 nm. For morphological study, veins were harvested immediately and 40 days after operation. Histological analysis of the vein after treatment with 1.5-W radiation revealed asymmetric wall injury and a thrombus formation in the lumen. The blood thrombus formation and pronounced vein wall damage was observed after treatment with 3-W radiation. Perivenous tissue injury is insignificant and does not lead to postoperative complications as in the case of using 1.5-W radiation. Increasing the radiation power to 4 W results in the total vein wall destruction and the thrombus formation, which persists for 40 days after the procedure. Based on the results of clinical observations of animals with registration of skin wound healing, as well as the results of histological examination of veins harvested immediately after the EVLC and 40 days after, it was concluded that the laser power value of 3-4 W can be recommended for use in the clinic.