Endovenous Laser Ablation: The Role of Intraluminal Blood

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.

The Inhibition of Prolyl Oligopeptidase as New Target to Counteract Chronic Venous Insufficiency: Findings in a Mouse Model

(1) Background: Chronic venous insufficiency (CVI) is a common disorder related to functional and morphological abnormalities of the venous system. Inflammatory processes and angiogenesis alterations greatly concur to the onset of varicose vein. KYP-2047 is a selective inhibitor of prolyl oligopeptidase (POP), a serine protease involved in the release of pro-angiogenic molecules. The aim of the present study is to evaluate the capacity of KYP-2047 to influence the angiogenic and inflammatory mechanisms involved in the pathophysiology of CVI. (2) Methods: An in vivo model of CVI-induced by saphene vein ligation (SVL) and a tissue block culture study were performed. Mice were subjected to SVL followed by KYP-2047 treatment (intraperitoneal, 10 mg/kg) for 7 days. Histological analysis, Masson's trichrome, Van Gieson staining, and mast cells evaluation were performed. Release of cytokines, nitric oxide synthase production, TGF-beta, VEGF, α-smooth muscle actin, PREP, Endoglin, and IL-8 quantification were investigated. (3) Results: KYP-2047 treatment ameliorated the histological abnormalities of the venous wall, reduced the collagen increase and modulated elastin content, lowered cytokines levels and prevented mast degranulation. Moreover, a decreased expression of TGF-beta, eNOS, VEGF, α-smooth muscle actin, IL-8, and PREP was observed in in vivo study; also a reduction in VEGF and Endoglin expression was confirmed in tissue block culture study. (4) Conclusions: For the first time, this research, highlighting the importance of POP as new target for vascular disorders, revealed the therapeutic potential of KYP-2047 as a helpful treatment for the management of CVI.

Prevalence and Mortality of Venous Leg Diseases of the Deep Veins: An Observational Cohort Study Based on German Health Claims Data

This study estimates the prevalence and mortality of diseases of the deep veins of the legs such as deep vein thrombosis (DVT), postthrombotic syndrome (PTS), and venous leg ulceration (VLU). We used a random sample of 250 000 patients at age 50+ years of the register of the Allgemeine Ortskrankenkasse from 2004 to 2015. Selected manifestations of venous diseases assumed as risk factors for mortality were analyzed using Cox models while adjusting for various basic demographic and health characteristics. The prevalence in 2004 was 0.05% for DVT of the femoral veins, 0.50% for DVT of any deep veins, 0.86% for PTS, and 0.91% for VLU. The mortality rate in 2004 to 2015 was 20.40 deaths/100 person-years for DVT of the femoral veins, 10.69 for DVT of any deep veins, 4.34 for PTS, and 7.02 for VLU. The model revealed a 35% higher risk (p < .001) in patients with any DVT, an 88% higher mortality (p < .001) for femoral DVT, a 23% higher risk (p < .001) for VLU, and no health disadvantage in persons with PTS. Our study revealed an increased mortality for patients with VLU and DVT. Even after adjustment for embolic events and infections of the venous ulcers mortality remained significantly higher.

Initial outcomes of endovenous laser ablation with 1940 nm diode laser in the treatment of incompetent saphenous veins

OBJECTIVES

To investigate the initial outcomes of 1940 nm diode laser in the treatment of incompetent saphenous veins.

METHODS

This was a prospective observational study. We treated 89 patients with 160 incompetent saphenous veins using a 1940 nm diode laser and bare fiber. The laser's power was set to 4.5 W with a mean linear endovenous energy density of 50.4 J/cm.

RESULTS

The one-month closure rate was 100%. The post-procedural pain score at 6 h, 1 day, 10 days, and 1 month was 0.85 ± 1.04, 0.65 ± 1.01, 0.82 ± 1.25, and 0.47 ± 0.82, respectively. Complications encountered included paresthesia (3.8%) and thrombophlebitis (4.4%), whereas no cases of endovenous heat-induced thrombosis were observed.

CONCLUSION

The 1940 nm laser and bare fiber at 50.4 J/cm showed satisfactory initial outcomes with less pain and fewer complications, in the treatment of incompetent saphenous veins.

Effect of spatial light distribution on the thermal response of vascular tissue

The aim of the current study is to investigate the effect of radial and cylindrical light distributions on the response of vascular tissue during 1470-nm irradiation in ex vivo models. Due to a low irradiance (5.3 W/cm²) and wide light distribution, cylindrically diffusing irradiation yielded uniform thermal coagulation while radial irradiation accompanied delamination of layers in leporine veins. Bovine foot model testing verified that the diffusing irradiation was associated with the steady maximum temperature and no tissue attachment, compared with the radial irradiation. The proposed cylindrical light application can be a feasible way to treat varicose veins in an effective manner.

Comparison of the effects of endovenous laser ablation at 1470 nm versus 1940 nm and different energy densities

OBJECTIVES

To evaluate histological and immunohistochemical changes in the great saphenous vein after endovenous laser ablation at two different wavelengths (1470 vs. 1940 nm) and linear endovenous energy density values (50 vs. 100 J/cm).

METHOD

Segments were obtained from the conventional eversion removal of great saphenous vein and divided into a control group and four groups for ex vivo irradiation (control group; A: 1470 nm, 50 J/cm; B: 1470 nm, 100 J/cm; C: 1940 nm, 50 J/cm; D: 1940 nm, 100 J/cm). Fifty venous segments ( n = 10/group) were analyzed. Changes were classified into low-temperature changes, moderate-temperature changes, high-temperature changes, and very high-temperature changes.

RESULTS

In the intima, low-temperature changes + moderate-temperature changes were significantly more prevalent in group A (65.4%) than in D ( p = 0.001). In the media, low-temperature changes + moderate-temperature changes were achieved mostly in groups A and C (77.4% and 75.0%, respectively). In adventitia fragments, 100% of changes in group A were low-temperature changes + moderate-temperature changes.

CONCLUSIONS

The 1940-nm laser wavelength with linear endovenous energy density of 100 J/cm was excessively destructive to the intima and media causing a high rate of high-grade thermal damage. These findings corroborate the possibility of using lower linear endovenous energy densities with 1940-nm devices to achieve effective occlusion with less high grade thermal damage to the intima and media, as well as to prevent damages to the adventitia and perivenous tissues, including venous perforation and its attendant clinical consequences.

Die chronische venöse Insuffizienz - Eine Zusammenfassung der Pathophysiologie, Diagnostik und Therapie

Die chronische Venenerkrankung ist eine weit verbreitete Krankheit, die in späteren Stadien mit einer Vielzahl an Symptomen, aber auch Komplikationen wie dem Ulcus cruris, einhergeht. Dies wiederum hat weitreichende Auswirkungen auf die Lebensqualität der Patienten wie auch auf das Gesundheitssystem. Für die Diagnostik der chronischen Venenerkrankungen steht eine Auswahl an Verfahren zur Verfügung, wobei sich die farbkodierte Duplexsonographie als Goldstandard etabliert hat. Im Bereich der Therapie kam es in den letzten Jahrzehnten zu großen Fortschritten, sodass heute auch Alternativen zum klassischen Stripping durch die endoluminalen Verfahren zur Verfügung stehen. Die Wahl der Therapieoption ist jedoch weiterhin stark abhängig von mehreren Faktoren, unter anderem von den anatomischen Gegebenheiten und dem Krankheitsstadium. Im folgenden Artikel werden die Anatomie und Pathophysiologie, sowie die aktuellen Standards der Diagnostik und Therapie zusammengefasst.

Chronic venous insufficiency - a review of pathophysiology, diagnosis, and treatment

Chronic venous disease is a common disorder associated with a variety of symptoms in later disease stages but also with complications such as venous leg ulcer. This, in turn, has substantial socioeconomic effects and significantly impacts patients' quality of life. While there are a number of diagnostic procedures available, color-flow duplex ultrasound has become the gold standard. As regards therapeutic options, major advances have been made in recent decades. Today, there are alternatives to saphenofemoral ligation and stripping of the great saphenous vein, including endovenous thermal ablation techniques. However, treatment selection continues to depend on many factors such as individual anatomical circumstances and disease stage. The following article provides an overview of the anatomy and pathophysiology as well as current diagnostic and therapeutic standards.

Resultados de médio e longo prazo do tratamento endovenoso de varizes com laser de diodo em 1940 nm: análise crítica e considerações técnicas

Contexto

Desde a introdução do laser endovenoso para tratamento das varizes, há uma busca pelo comprimento de onda ideal, capaz de produzir o maior dano seletivo possível com maior segurança e menor incidência de efeitos adversos.

Objetivos

Avaliar os resultados de médio e longo prazo do laser de diodo de 1940 nm no tratamento de varizes, correlacionando os parâmetros utilizados com a durabilidade do desfecho anatômico.

Métodos

Revisão retrospectiva de pacientes diagnosticados com insuficiência venosa crônica em estágio clínico baseado em clínica, etiologia, anatomia e patofisiologia (CEAP) C2 a C6, submetidos ao tratamento termoablativo endovenoso de varizes tronculares, com laser com comprimento de onda em 1940 nm com fibra óptica de emissão radial, no período de abril de 2012 a julho de 2015. Uma revisão sistemática dos registros médicos eletrônicos foi realizada para obter dados demográficos e dados clínicos, incluindo dados de ultrassom dúplex, durante o período de seguimento pós-operatório.

Resultados

A média de idade dos pacientes foi de 53,3 anos; 37 eram mulheres (90,2%). O tempo médio de seguimento foi de 803 dias. O calibre médio das veias tratadas foi de 7,8 mm. A taxa de sucesso imediato foi de 100%, com densidade de energia endovenosa linear (linear endovenous energy density, LEED) média de 45,3 J/cm. A taxa de sucesso tardio foi de 95,1%, com duas recanalizações por volta de 12 meses pós-ablação. Não houve nenhuma recanalização nas veias tratadas com LEED superior a 30 J/cm.

Conclusões

O laser 1940 nm mostrou-se seguro e efetivo, em médio e longo prazo, para os parâmetros propostos, em segmentos venosos com até 10 mm de diâmetro.

Predictors of Recanalization of the Great Saphenous Vein in Randomized Controlled Trials 1 Year After Endovenous Thermal Ablation

OBJECTIVE/BACKGROUND

The objective was to identify predictors to develop and validate a prognostic model of recanalization of the great saphenous vein (GSV) in patients treated with endovenous thermal ablation (EVTA).

METHODS

The search strategy of Siribumrungwong was updated between August 2011 and August 2014 using MEDLINE, Embase, and the Cochrane register to identify randomized controlled trials (RCTs), in which patients presenting with GSV reflux were treated with radiofrequency or endovenous laser ablation. Leg level data (n = 1226) of 15/23 selected RCTs were pooled. The primary outcome was recanalization of the GSV; the secondary outcome was change in health related quality of life (HRQoL) measured by the Chronic Venous Insufficiency quality of life Questionnaire or Aberdeen Varicose Vein Questionnaire 1 year post-procedure. Candidate predictors were age, sex, body mass index, clinical class, GSV diameter, saphenofemoral junction reflux, type of device, energy, and length of treated vein.

RESULTS

At 1 year, 130 GSVs were recanalized (11%). Clinical class (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.4-3.3) and diameter (OR 1.8, 95% CI 1.2-2.7) of the GSV were the strongest predictors of recanalization. Other predictors included in the final model were sex, type of device, and length of treated vein. The performance of the recanalization model was moderate, with an area under the curve above 0.717. GSV diameter, type of device, and amount of energy delivered were the only predictors of the change of HRQoL. None of the candidate predictors were included in the final HRQoL model (R(2) = .027).

CONCLUSION

There are several important prognostic factors for GSV recanalization and change of HRQoL after EVTA. However, the performance of each model was unsatisfactory to allow use in clinical practice yet.

Investigation of endovenous laser ablation of varicose veins in vitro using 1.885-μm laser radiation

This paper presents the results of endovenous laser ablation (EVLA) of varicose veins in vitro using radiation of a solid-state laser based on the crystal LiYF4:Tm, with a wavelength of 1.885 μm and power output of around 3 W. An experimental series with saline solution and red blood cell (RBC) suspension in the venous lumen was performed to identify the impact of a heated carbonized layer precipitated on the fiber end face versus the efficiency of EVLA. Results of these experiments confirmed that the presence of a heated carbonized layer on the fiber end face increases the efficiency of EVLA.

The Histological Changes of the Great Saphenous Vein at 2 Years after Cryosclerosis

Cryosclerosis was developed at the end of the last decade. It is the endovenous cryoablation of the great saphenous vein and has been forgotten before the era of the endovenous ablation techniques began. The caused histomorphological changes of the vein weren’t described before, especially, years after the procedure. A 31-year-old female patient underwent cryosclerosis 2 years ago. Because of the recanalization of the great saphenous vein and recurrent varicosity, high ligation, cryostripping and phlebectomy of varices were performed. During surgery, a saphenous vein piece was harvested to investigate the histomorphological effect of cryosclerosis. Histological findings verified that recanalization had occurred, the vein wall had undergone remodeling, and the picro-sirius red stain showed collagen deposition in the whole vein wall. Cryosclerosis seems to result in the remodeling of the vein wall.

Endovenous laser ablation (EVLA): a review of mechanisms, modeling outcomes, and issues for debate

Endovenous laser ablation (EVLA) is a commonly used and very effective minimally invasive therapy to manage leg varicosities. Yet, and despite a clinical history of 16 years, no international consensus on a best treatment protocol has been reached so far. Evidence presented in this paper supports the opinion that insufficient knowledge of the underlying physics amongst frequent users could explain this shortcoming. In this review, we will examine the possible modes of action of EVLA, hoping that better understanding of EVLA-related physics stimulates critical appraisal of claims made concerning the efficacy of EVLA devices, and may advance identifying a best possible treatment protocol. Finally, physical arguments are presented to debate on long-standing, but often unfounded, clinical opinions and habits. This includes issues such as (1) the importance of laser power versus the lack of clinical relevance of laser energy (Joule) as used in Joule per centimeter vein length, i.e., in linear endovenous energy density (LEED), and Joule per square centimeter vein wall area, (2) the predicted effectiveness of a higher power and faster pullback velocity, (3) the irrelevance of whether laser light is absorbed by hemoglobin or water, and (4) the effectiveness of reducing the vein diameter during EVLA therapy.

Endovenous laser ablation: a review of mechanisms of action

BACKGROUND

The aim of this article is to summarize and review the proposed theories on the laser action during endovenous ablation.

METHODS

Laser mechanics and laser-tissue interaction are summarized from articles found in literature. Several theories, like the "steam bubble theory," the "direct contact theory," the "heat pipe," and "direct light energy absorption" are discussed.

RESULTS

The laser light emitted intraluminally can be absorbed, scattered, or reflected. Reflection is negligible in the near-infrared spectrum. By combining absorption and scattering, the optical extinction of different wavelengths related to different biological tissues can be determined. The direct contact of the fiber tip and the vein wall may be a way of destroying the vein wall, but results in ulcerations and perforations of the vein wall. Avoiding this contact, and allowing direct light absorption into the vein wall, results in a more homogenous vein wall destruction. If the energy is mainly absorbed by the intraluminal blood, the laser fiber will act as a heat pipe. Histological studies show that a more circumferential vein wall destruction can be obtained when the vein is emptied of its intraluminal blood. The use of tumescent liquid reinforces spasm of the vein and protects the perivenous tissue.

CONCLUSION

Several factors play an important role in the mechanism of endovenous laser ablation. Direct energy absorption by the vein wall is the most efficient mechanism. It is important to empty the vein of its intraluminal blood and to inject tumescent liquid around the vein.