Safety and efficacy of endovenous laser ablation (EVLA) using 1940 nm and radial emitting fiber: 3-year results of a prospective, non-randomized study and comparison with 1470 nm

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.

Prospects of Endovenous Laser Ablation (EVLA) Standardization-Mid-Term Results of a Four-Zone Dosimetry Guiding Tool for 1940 nm Laser

BACKGROUND

Heterogeneity regarding dosimetry and reporting of endovenous laser ablation (EVLA) mandates the development of a standardized protocol. This study presents the mid-term results of EVLA with 1940 nm-laser and radial-fibre, supported by a four-zone dosimetry tool.

MATERIALS AND METHODS

Four anatomical dosimetry zones for great saphenous veins (GSV) and two for small saphenous veins (SSV) were defined with set power levels. Zone-1G (4 W) extended from the inguinal ligament to the apex of femoral triangle, Zone-2G (4 W) from the apex of femoral triangle to the upper border of patella. Zone-3G (3 W) from the patella to the tibial tuberosity. Zone-4G (2 W) extended from the tibial tuberosity to the ankle. Zone-1S from the sapheno-popliteal junction to the tibial tuberosity. Zone-2S from the tibial tuberosity to the ankle. Power was increased by 1 W for veins >10 mm and decreased by 1 W when fibre sticking was encountered. Pullback-velocity was max. 1 mm/s.

RESULTS

A total of 152 consecutive patients (185 procedures) were recruited. Mean follow-up time was 11.9 months. Mean linear endovenous energy density for GSV was Zone-1G:42 J/cm, Zone-2G:33 J/cm, Zone-3G:27 J/cm, Zone-4G:22 J/cm, Zone-1S:34 J/cm, Zone-2S:27 J/cm. Occlusion rates were 98.9% (1-month) and 93.7% (12-months). Complications at 1 M were low, namely laser-induced paraesthesia (LIP) 2.2% and endovenous heat-induced thrombosis (EHIT) 1.6%. Persistent LIP (12 M) was observed in 0.5%.

CONCLUSION

The proposed four-zone guiding tool is a step towards standardizing dosimetry and documentation for EVLA with 1940 nm. This strategy shows good mid-term results with minimal complications. Long-term follow-up and application in further centres are necessary to prove its reproducibility. Such a guiding tool could improve the ability to analyse, compare and review different EVLA wavelengths and fibre types.

Endovenous laser ablation using laser systems emitting at wavelengths > 1900 nm: a systematic review

The aim of this systematic review was to summarize the currently available literature reporting clinical application of endovenous laser ablation (EVLA) by means of laser systems emitting at wavelengths > 1900 nm, pertaining dosimetry, intraoperative parameters, postoperative outcomes, and efficacy based on occlusion rates, recanalization, and postoperative complications. A literature search was conducted in PubMed, Cochrane Library, Embase, OVID, and Web of Science for publications since the year 2000 until December 2021. Case series, prospective trials, retrospective studies, and randomized controlled trials describing the application of a 1920/1940-nm wavelength laser for EVLA in humans with a minimum of one postoperative follow-up visit were included in the study. Four case series and one randomized controlled trial with a total of 509 EVLA procedures (396 great saphenous veins and 113 small saphenous veins) were identified, meeting the inclusion criteria. The studies were heterogenous in their documentation, EVLA, and duplex ultrasound protocol and result reporting. Overall, the applied average cumulative LEED values ranged from 17.8 to 53 J/cm. Complications observed were pigmentation (0-9.75%), paresthesia (2.5-7.3%), thrombophlebitis (0-5%), EHIT Class 2 (2.26-2.4%), and EHIT Class 1 (1.2-2.4%). Four cases of recanalizations were observed in one study cohort within the first month after treatment. Follow-up at 12 months was available for 3 studies (procedures n = 218) with recanalizations in 8 limbs. Follow-up at 24-36 months was available for 2 studies (procedures n = 126) showing recanalizations in 5 limbs. Recanalizations were asymptomatic and incidental findings on follow-up duplex ultrasound. Pooled occlusion rates were 99.2% at 1 M, 96.3% at 12 M, and 96% at 24 M. Overall, patients undergoing EVLA with long wavelength laser systems > 1900 nm show high occlusion rates, significant improvement in VCSS, low postoperative complication rate, low pain levels, low analgesic requirement, and early convalescence. Apart from persistent paresthesia, all the complications regressed spontaneously within 6 months. EVLA by means of 1920/1940 nm shows promising clinical results with high efficacy and low complication rates. Heterogeneity still exists regarding ideal protocol for duplex ultrasound examination and documentation of anatomical parameters (e.g., vein diameter, ideal stump length and status of accessory veins) and light dosimetry for EVLA.