Commonly Used Endovenous Laser Ablation (EVLA) Parameters Do Not Influence Efficacy: Results of a Systematic Review and Meta-Analysis

Defining the Parameters for Endovenous Microwave Ablation to Achieve Equivalence With Endovenous Laser Ablation, Using the Porcine Liver Model

AIMS

Endovenous microwave ablation (EMWA) is an endovenous thermoablation (EVTA) system to ablate incompetent truncal veins. Early results suggest that EMWA uses more power than endovenous laser ablation (EVLA) to get the same results. We aimed to define the parameters for EMWA, which give the same tissue ablation as EVLA, using the validated porcine liver model.

METHODS

EVLA (1470 nm 600 micron radial fibre) treatments were performed at 6 W, 8 W and 10 W, at pullback speeds of 6, 7, 8 and 9 s/cm, giving Linear Endovenous Energy Densities (LEEDs) between 36 - 90 J/cm. Each combination of power and pullback was repeated 5 times. We then used EMWA in the same model. Powers of 35-75 W and pullback speeds of 4-9 s/cm were used (LEEDs 140-675 J/cm). Ablation tracts from both devices were analysed by 2 blinded observers, noting thermal spread and carbonisation.

RESULTS

For each commonly used parameter for EVLA, we identified a range of parameters for EMWA that produced similar tissue ablation in the porcine liver model. To keep the pullback speeds within the usual range, powers of 35-75 W were needed with EMWA, with mean EMWA LEEDs 3.9 - 5.8 times higher than EVLA LEEDs. We found the quicker the pullback speed, the higher the multiple of EMWA LEED we needed to get the same effect.

CONCLUSION

We have identified parameters for EMWA that gave equivalent tissue ablation in the porcine liver model to commonly used parameters used for EVLA. These need to be validated clinically, but as the model used has already been validated against clinical outcome in endovenous thermal ablation, there is little reason to suspect that these results would not be valid. As the power during EMWA is higher than EVLA, EVMA LEEDs are approximately 4-6 times higher than EVLA LEEDs to achieve the same thermal effect on the tissues.

[Varicosis-Current treatment concepts]

Varicosis is a chronic progressive disease characterized by varicose veins of the lower extremities. Pain, swelling and heaviness of the legs are typical symptoms. These symptoms are caused by a pathological venous reflux, arising from a weakness of the vein wall and progressive venous insufficiency. The indications for invasive surgery are the symptomatic clinical, etiological, anatomical, pathophysiological (CEAP) stages C2s-C6. Compression therapy and venoactive drugs can be recommended for conservative therapy. When it comes to surgical treatment conventional open vein surgery is associated with the best long-term results. Endovenous thermal ablation is associated with few postoperative complications and favors earlier mobilization of the patient. Sclerotherapy has become established with good clinical results for the ablation of reticular and telangiectatic veins, for recurrences and complicated vein anatomy.

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.

Value and limitations of postoperative duplex scans after endovenous thermal ablation

BACKGROUND

Endovenous thermal ablation (EVTA) of the lower extremity veins has risen to become the main treatment modality for symptomatic venous reflux disease. One of the main reported side effects of EVTA is recanalization. As of today, there is no clear protocol as to when follow-up duplex ultrasound scans should be performed. However, the standard for postoperative duplex after truncal ablation is within 1 week of the procedure. Our aim is to try to find whether there is a particular time period when postoperative duplex ultrasound scans should be performed to allow us to best diagnose recanalization.

METHODS

We retrospectively analyzed 9799 procedures in 3237 patients with chronic venous insufficiency owing to great, small, and anterior accessory saphenous vein insufficiency from 2012 to 2018. We excluded 466 perforator veins. All 9799 procedures were performed using EVTA in patients who failed to respond to conservative management initially. Postoperative duplex ultrasound scans were performed within 1 week (3-7 days postoperatively). We defined a successful obliteration as lack of color flow on postoperative scan. We defined symptomatic recanalization as presence of reflux on duplex ultrasound examination in the targeted vessel at follow-up with symptom recurrence. Follow-ups were performed every 3 months in the first year and every 6 months thereafter.

RESULTS

Patient ages ranged from 15 to 99 years. The median patient age at the time of the procedures was 63 years (interquartile range [IQR], 51-73 years). The median overall follow-up was 25 months (IQR, 4-56 months). The Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) class of all the procedures were: C1, 21; C2, 208; C3, 3585; C4, 4680; C5, 188; and C6, 1117. There were 145 redo procedures performed after symptomatic recanalization was diagnosed in patients. CEAP class of the redo patients were: C1, 0; C2, 2; C3, 49; C4, 70; C5, 5; and C6, 19.

CONCLUSIONS

Most patients underwent a redo procedure performed within the first year after the initial procedure. Conversely, there was great variability as to when redo procedures were performed. Because there is no defined pattern as to when these symptomatic occurrences arise, it may not be required to perform postoperative duplex ultrasound scans after EVTA routinely, but instead when a patient comes back with symptoms such as swelling.

Laser ablation on vascular diseases: mechanisms and influencing factors

Vascular diseases, such as venous insufficiency and coronary artery diseases, have been threatening the health of people. Efficient treatment with proper postoperative care is required to relieve the pain of the patients. Traditionally, venous insufficiency is treated with ligation and stripping, an open surgery whose complication rate cannot be ignored. Coronary artery disease is often treated with balloon angioplasty during which undilatable lesions may be encountered, limiting the efficacy of this approach. With advances in laser photonics and percutaneous coronary intervention procedure, laser ablation is emerging as an alternative and adjunctive therapy for these diseases. Endovenous laser ablation has the advantages of high success rate, low complication risk, and fast postoperative recovery. Laser ablation in arteries can handle uncrossable or undilatable lesions with a low incidence of serious complications. In this review, previously published research concerning vascular diseases and their therapies are analyzed in order to provide a clear explanation of the mechanisms and merits of laser ablation. For endovenous laser ablation, the main mechanisms are steam bubbles, heat conduction, and heat pipe, and three main influencing factors are wavelength, fiber types, and laser energy density. For excimer laser coronary atherectomy, the main mechanisms are photochemical, photothermal, and photomechanical effects, and three main influencing factors are catheter, medium, and laser parameters.

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 Systematic Review and Meta-Analysis of Randomised Controlled Trials Comparing Thermal Versus Non-Thermal Endovenous Ablation in Superficial Venous Incompetence

OBJECTIVE

The objective was to compare technical success, complications, and quality of life after thermal vs. non-thermal endovenous ablation for the treatment of superficial venous incompetence.

DATA SOURCES

Electronic bibliographic sources (Google Scholar, Pubmed, Cochrane Database, Scopus, Web of Science, and Embase).

REVIEW METHODS

A systematic review and meta-analysis of randomised controlled trials was conducted using terms to identify relevant studies to be included. The primary outcome was vein occlusion rate at up to four weeks and one to two years from procedure. Secondary outcome measures included peri-procedural pain, nerve injury, endothermal heat induced thrombosis, and quality of life.

RESULTS

Eight randomised controlled trials met the selection criteria. These comprised a total of 1 956 patients, of whom 1 042 underwent endovenous thermal ablation and 915 underwent endovenous non-thermal ablation. There was no statistically significant difference in occlusion rate at all time points. Relative risk at four weeks and one to two years was 0.99 (95% CI 0.96 - 1.02) and 0.95 (95% CI 0.88 - 1.01), respectively. Non-thermal ablation was tolerated better and had less risk of nerve injury. There was no statistically significant difference in risk of endothermal heat induced thrombosis (EHIT). There was improvement in quality of life scores post-procedure but there was no statistically significant difference in thermal vs. non-thermal ablation. The quality of evidence assessed using GRADE methodology showed high quality for occlusion rate at four weeks and one to two years, moderate quality for nerve injury and peri-procedural pain, and low quality for EHIT.

CONCLUSION

Vein occlusion rates after thermal vs. non-thermal endovenous ablation are similar. In the early post-operative period, non-thermal endovenous ablation demonstrated the advantages of less pain and less risk of nerve injury. Improvement in quality of life after both thermal and non-thermal endovenous ablation is similar.

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.

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.

Linear endovenous energy density (LEED) should always be quoted with the power used in endovenous thermal ablation - results from an in-vitro porcine liver model study

BACKGROUND

Linear Endovenous Energy Density (LEED) is the energy used per cm of vein in endovenous thermal ablation (EVTA) but does not include time. This study examines the effect of time during EVTA.

METHOD

EVTA was performed in a previously validated porcine liver model. LEEDs of 40, 60, 80 and 100 J/cm, using different powers were repeated 5 times each. Thermal spread, tissue carbonisation and device-tissue sticking during treatment were recorded.

RESULT

LEED positively correlated to thermal spread and carbonisation of the tissue. Power was correlated with carbonisation but not thermal spread. Pullback had no correlations with thermal spread or carbonisation. Catheter sticking found occurred in powers >= 15 W or LEED >= 80 J/cm.

CONCLUSION

LEED is a good measure of EVTA but does not include time. Power, which does include time, correlates with carbonisation and with device-tissue sticking. The power used must be quoted with the LEED.

Comparing the Effects of Radial and Jacketed Laser Tip Fibers on Outcome of Endovenous Laser Ablation of Lower Limb Truncal Venous Reflux

BACKGROUND

Saphenous vein reflux is one of the leading causes of cosmetic and functional disabilities. The recent European Society of Vascular Surgery guidelines recommend endovenous thermal ablation over surgery or sclerotherapy for the treatment of great saphenous vein (GSV) reflux in patients with chronic venous disease. The aim of this study is to compare different laser fiber tip configurations to outcome regarding technical success and incidence of complications.

DESIGN

A retrospective analysis conducted on patients with documented GSV reflux from 2020 to 2022, comparing baseline parameters and outcome between 2 groups of laser tip fibers used; radial tip and jacketed tip. Primary end point was technical success. Secondary endpoints included incidence of complications in each group, and VCSS score difference in both groups.

METHODS

Inclusion criteria entailed patients with primary varicose veins over the age of 18 years, free from malignancy, hematological disorders, and having documented GSV reflux of more than 0.5 sec. All patients had endovenous laser ablation (EVLA) of the GSV, with complementary foam sclerotherapy or ambulatory phlebectomies as required.

RESULTS

A total of 74 patients underwent EVLA (85 limbs). Fifty-four were done using the radial laser fibers, and 32 using jacketed fibers. Technical success was achieved in 78 limbs (92.9%), 6 limbs (7.1%) had recanalization of the proximal 3 cm of the GSV at 1 month, 2 patients experienced hematomas, and 5 patients had superficial vein thrombosis. There was no significant association between postoperative pain, bruising, recanalization, hematoma formation, and superficial vein thrombosis with different laser fiber tip configurations (P-value 0.95, 0.6, 0.18, 1, and 1, respectively), nor was there any significant difference in VCSS between them (P-value 0.14).Technical success was 90% in the jacketed fibers and 94.1% in the radial fibers group (P-value 0.18).

CONCLUSIONS

Neither does laser fiber tip configuration nor its make have a significance on outcome of EVLA of GSV reflux. Both radial and jacketed laser fiber tips exhibit similar safety and efficacy in EVLA.

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.

Strategies and challenges in treatment of varicose veins and venous insufficiency

Patients with varicose veins can be treated with conservative or surgical approaches based on the clinical conditions and patient preferences. In the recent decade, the recommendations for managing symptomatic varicose veins have changed dramatically due to the rise of minimally invasive endovascular techniques. The literature was systematically searched on Medline without language restrictions. All papers on the treatment of varicose veins and venous insufficiency with different procedures were included and reviewed. Endovenous laser ablation (EVLA) and radiofrequency ablation (RFA) both are same safe and effective in terms of occlusion rate, and time to return to normal activity. In comparison with RFA or EVLT, Cure conservatrice et Hemodynamique de l'Insufficience Veineuse en Ambulatoire (CHIVA) may cause more bruising and make little or no difference to rates of limb infection, superficial vein thrombosis, nerve injury, or hematoma. In terms of recurrence of varicose veins, there is little or no difference between CHIVA and stripping, RFA, or EVLT. Great saphenous vein recanalization is highest in the ultrasound-guided foam sclerotherapy (FS) group (51%) during 1 year of follow-up. The 2013 National Institute for Health and Care Excellence clinical guidelines recommend surgery as a third-line therapeutic option after EVLA or RFA and sclerotherapy. Although the mechanochemical endovenous ablation (MOCA) is a non-thermal, non-tumescent option and appears to be of similar efficacy to stab avulsion with no potential risk of nerve damage, the overall success rate of MOCA is lower than those of other procedures such as EVLA, RFA, or high ligation and stripping. EVLA is the most cost-effective therapeutic option, with RFA being a close second for the treatment of patients with varicose veins. Endovenous thermal ablation (EVLA or RFA) is recommended as a first-line treatment for varicose veins and has substituted the high ligation of saphenofemoral junctional reflux and stripping of varicose veins. Ultrasound-guided FS is associated with a high recurrence rate and can be used in conjunction with other procedures. MOCA and cyanoacrylate embolization appear promising, but evidence of their effectiveness is required.

Review on Laser Technology in Intravascular Imaging and Treatment

Blood vessels are one of the most essential organs, which nourish all tissues in our body. Once there are intravascular plaques or vascular occlusion, other organs and circulatory systems will not work properly. Therefore, it is necessary to detect abnormal blood vessels by intravascular imaging technologies for subsequent vascular treatment. The emergence of lasers and fiber optics promotes the development of intravascular imaging and treatment. Laser imaging techniques can obtain deep vascular images owing to light scattering and absorption properties. Moreover, photothermal and photomechanical effects of laser make it possible to treat vascular diseases accurately. In this review, we present the research progress and applications of laser techniques in intravascular imaging and treatment. Firstly, we introduce intravascular optical coherent tomography and intravascular photoacoustic imaging, which can obtain various information of plaques. Multimodal intravascular imaging techniques provide more information about intravascular plaques, which have an essential influence on intravascular imaging. Secondly, two laser techniques including laser angioplasty and endovenous laser ablation are discussed for the treatment of arterial and venous diseases, respectively. Finally, the outlook of laser techniques in blood vessels, as well as the integration of laser imaging and treatment are prospected in the section of discussions.

1470 nm/980 nm dual-wavelength laser is safe and efficient for the en-bloc resection of non-muscle invasive bladder cancer: A propensity score-matched analysis

OBJECTIVE

To evaluate the efficacy and safety of a 1470 nm/980 nm dual-wavelength laser system used for the en-bloc resection of non-muscle invasive bladder cancer (NMIBC) compared with transurethral resection of bladder tumour (TURBT).

METHODS

This retrospective study analysed the demographic and clinical data from patients diagnosed with NMIBC that were treated by either dual laser or TURBT. Intraoperative characteristics, postoperative characteristics and outcomes between the two groups were compared.

RESULTS

This study analysed 64 patients, 32 in each group. No severe complications were identified in either group. After propensity score-matching, there were no significant differences between the two groups in terms of the demographics, clinical and tumour characteristics. There was no significant difference between the two groups in terms of specimen quality. In the laser group, intraoperative blood loss was significantly lower and significantly fewer patients required continuous bladder irrigation after surgery, compared with the TURBT group. No significant differences were observed in the catheterization time, gross haematuria time and hospitalization time. Operation time in the laser group was significantly longer compared with the TURBT group. No significant difference was found in the recurrence and progression rates between the two groups.

CONCLUSIONS

The 1470 nm/980 nm dual-wavelength laser provides a safe and effective surgical treatment option for patients with NMIBC.

Treatment of chronic venous disorder: A comprehensive review

Chronic venous disorder (CVD) is highly prevalent vascular disorder affecting up to 45% of the general population, with clinical manifestations ranging from teleangiectasias to venous leg ulcers (VLUs). We examined the currently available data in order to provide an updated, comprehensive review on treatment options of CVD. We searched MEDLINE, Cochrane, Scopus, EMBASE, ClinicalTrials, and OpenGrey databases for relevant articles in English published until November 2020. Compression treatment is the mainstay of conservative treatment. Pharmacological treatment can provide significant symptomatic relief and hence it should be considered as part of conservative treatment. Transcutaneous Lacer treatment (TCL) is a safe and effective alternative option to sclerotherapy for treatment of C1 stage. High ligation and stripping (HL/S), ultrasound-guided foam sclerotherapy (UGFS), endovenous thermal ablation (EVTA) systems and non thermal non tumescent ablation (NTNT) systems are safe and efficacious first-line options for treatment of saphenous insufficiency. Interventional treatment of co-existing incompetent perforator veins (IPVs) is not supported by contemporary evidence. Regarding deep venous insufficiency (DVI), treatment of symptomatic femoroiliocaval occlusive venous disease refractory to conservative treatment with percutaneous transluminal venoplasty stenting has produced encouraging results.

No significant difference between 1940 and 1470 nm in endovenous laser ablation using an in vitro porcine liver model

Current endovenous laser ablation (EVLA) practice favours 1470 nm, as water is a major chromophore for this wavelength. Water has a greater affinity for 1940 nm, leading to claims that lower powers or linear endovenous energy densities (LEEDs) are needed. We compared the thermal spread and carbonisation of EVLA using these two wavelengths, in the porcine liver model. Using the previously validated porcine liver model, we performed 5 treatments, at each power: 2 W, 4 W, 6 W, 8 W and 10 W using a standard pullback of 8 s/cm. This gave LEEDs for each wavelength of 16, 32, 48, 64 and 80 J/cm. Digital images were given random codes and analysed by two blinded observers. Thermal spread was measured using "SketchandCalc" online software and graded carbonisation from 0 (none) to 3 (black carbon tract). There was no significant difference in thermal spread between the two wavelengths at 6 W, 8 W and 10 W. At 2 W, the 1470-nm laser had a significantly increased thermal spread over the 1940 nm. Significantly more carbonisation was found with the 1940-nm laser compared to 1470 nm. In this model, there was no significant difference in thermal spread at powers of 6 W and more. At 2 W and potentially 4 W, 1470 nm showed spread than 1940 nm, due to increased absorption at the device/tissue interface. At powers and LEEDs used for saphenous ablation, we found no evidence to support reduced power or LEED when using 1940 nm. However, 1940 nm may be more advantageous than 1470 nm when ablating small thin-walled veins, near to the skin.

Morphological changes of veins and perivenous tissues during endovenous laser coagulation using 2-μm laser radiation and various types of optical fibers

OBJECTIVE

To determine the morphological changes in veins and perivenous tissues after endovenous laser coagulation (EVLC) using laser radiation with a wavelength of 1910 nm and different types of fibers (bare tip and radial).

METHODS

The EVLC procedure was carried out on 22 surface veins of six sheep. The radiation source was a diode-pumped solid-state laser, which was based on a LiYF₄:Tm crystal and had an emission wavelength of 1910 nm and a maximum output power of 10 W. Two types of optical fibers were used: (1) bare tip and (2) radial or radial with two rings. Histological and morphometric methods were used, and the statistical digital data were analyzed.

RESULTS

The use of a linear endovenous energy density of 20 J/cm and optical bare fibers for veins with diameters of 3-4 mm resulted in a slit-shaped or wide venous wall perforation. A thermal effect was observed on the perivenous connective tissue (PVCT), which caused damage to its structures. Wide perforations were accompanied by complete destruction of the PVCT in the projection of the formed defect. The distance between the remaining vein wall fragment, located opposite to the perforation, and injured small vessels was 257.7 ± 23.6 μm. The radius of thermal damage increased to 2073.5 ± 8.0 μm near the vessel perforation. Using optical radial fibers for veins with diameters of 3.9 ± 0.5 mm did not lead to perforations. The destructive effect of the laser on small vessels of the PVCT extended to a distance of 425.7 ± 22.0 μm.

CONCLUSIONS

Analysis of thermal vessel damage in perivenous tissue after EVLC with bare-tip fiber shows that in the projection of a wide perforation, the damaged vessels of the PVCT are located at a large distance from the coagulated vein wall. On the opposite side of the perforation, the distance from the coagulated vein wall to the damaged vessels of the PVCT is significantly reduced because of the minimal output of laser radiation energy through the poorly damaged part of the wall. Using an optical radial fiber facilitates the application of a uniform distribution of thermal energy to the vein wall and damage to all its layers; at the same time, it minimizes the thermal energy that extends beyond the vein wall and damages the surrounding tissue.

CLINICAL RELEVANCE

The use of radiation with a wavelength of 1910 nm will make it possible to carry out endovenous laser coagulation of varicose veins at lower power values compared with radiation in the micron and one and a half micron regions of the spectrum. Understanding of morphological changes of veins and perivenous tissues after endovenous laser coagulation with 1910-nm laser radiation and different types of optical fibers (bare-tip, radial, radial 2ring) help predict possible complications and reduce their rate.

Current strategies for endovascular management of varicose veins: An updated review of superficial ablation technologies

Chronic venous insufficiency (CVI) which causes varicose veins and venous ulcers, is a major cause of morbidity and mortality in the general population. The last several years have witnessed many revolutionary developments in the realms of minimally invasive techniques (both thermal and non-thermal) to treat CVI. Moreover, multiple newer societal recommendations have been published over the past one year on the basis of the current evidence. In this article, we will briefly summarise the imaging for varicose veins and review the existing evidence in literature as well as the current guidelines and recommendations for the management of varicose veins, especially focusing on the various superficial ablation technologies.

Use of 1,470 nm laser for treatment of superficial venous insufficiency

Background

There are several ways to treat varicose veins of the lower limbs, among which use of 1470nm diode lasers stands out. This technique can be used to treat patients in outpatient settings, with early return to work, good esthetic results, and low rates of complications. However, variables such as the laser wavelength, the power administered in each area, the type of fiber, and the linear intravenous energy density (LEED) are still extensively discussed.

Objectives

To analyze the results of superficial venous insufficiency treatment with a 1470nm diode laser.

Methods

Retrospective study conducted at a private clinic in a private hospital in Florianopolis, based on a database collected prospectively. The sample comprised 287 patients who underwent surgery to treat superficial venous insufficiency with 1470nm diode laser, from January 2016 to December 2018, totaling 358 great saphenous veins (GSVs) and 84 small saphenous veins (SSVs) treated.

Results

The total occlusion rates after 12 months of surgery were 94.4% in the GSVs, with an average LEED of 45.90 J/cm, and 96.4% in the SSVs, with an average LEED of 44.07 J/cm.

Conclusions

During the follow-up period, the 1470nm diode laser proved to be a safe treatment, with great efficacy and low rates of complications (pain, edema, bruising, deep vein thrombosis, and endothermal heat-induced thrombosis - EHIT).

Diagnosis and treatment of varicose veins and chronic venous insufficiency

This study aimed to review the pathophysiology of varicose veins and chronic venous insufficiency and the recent surgical treatment trend. Varicose veins are tortuous, twisted, or lengthened veins in the lower extremities. It is part of the spectrum of chronic venous disease. Primary pathogenesis is increased chronic venous hypertension caused by valvular insufficiency, venous outflow obstruction, and calf muscle pump failure. Some patients complain of no symptoms, except report cosmetic concerns. If the varicose vein progresses to chronic venous insufficiency, it may cause edema of the lower limb. The skin lesion can present as hyperpigmentation of the median part of the ankle, congestive dermatitis, and even a skin ulcer. The varicose vein can be diagnosed easily by visual inspection after identifying the skin lesions. For non-surgical treatment, elastic stocking, Unna boots, and pneumatic compression devices are recommended to reduce venous pressure. High ligation with stripping has been the standard treatment for varicose veins to achieve symptom relief and improve cosmetic effects. Endovenous laser ablation, radiofrequency ablation, mechanochemical ablation, and the VenaSeal closure system have been introduced as surgical treatment methods. Recently, endovenous thermal/non-thermal ablations are recommended for treatment because both are less invasive techniques. The appropriate therapy should be selected after considering the patients’ symptoms and signs, anatomical structure, and economic burden of the treatment.