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

Malskat, Wendy S J; Poluektova, Anna A.; Geld, C.W.M. van der; Neumann, H. A. Martino; Weiß, Robert; Bruijninckx, C.M.A.; Gemert, Martin J. C. van

doi:10.1007/s10103-013-1480-5

Cited by 76 publications

(86 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…* Classification described by Kabnick et al 15 proportional to the coefficient of absorption μ A (cm -1 ) multiplied by the irradiance (W/cm 2 ) and linearly dependent on exposure time. 25,31 While the heat produced in the tissue, from the optical energy absorbed and released as heat, is dependent on the optical properties of the tissues and on the parameters of irradiation, such as irradiance and exposure time, the process of conductive thermal diffusion is responsible for transmission (flow) of heat generated locally (flow of heat from a higher-temperature region to a lower temperature region). 25 In other words, the parameter that governs the entire interaction between laser and tissue, in relation to lasers that work by photothermal effects, is temperature.…”

Section: Adverse Events N (%)mentioning

confidence: 99%

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

Viarengo¹,

Viarengo²,

Martins³

et al. 2017

J. vasc. bras.

View full text Add to dashboard Cite

Resumo 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.

show abstract

Section: Adverse Events N (%)mentioning

confidence: 99%

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

Viarengo¹,

Viarengo²,

Martins³

et al. 2017

J. vasc. bras.

View full text Add to dashboard Cite

show abstract

“…Steam bubbles cannot significantly heat a venous wall, as the density of saturated vapor at the atmospheric pressure even at 100°C is only 6·10 -4 of the water density, while the similarity with a heat-pipe is not correct because bubbles contain not only water vapors but some other gases as well [7][8][9].…”

Section: No2 7 Advanced Researchesmentioning

confidence: 99%

Contribution of Laser-Induced Gas-Vapor-Liquid Dynamics to the Mechanism of Endovenous Laser Ablation

Чудновский¹,

Yusupov²,

Захаркина³

et al. 2016

Sovrem Tehnol Med

View full text Add to dashboard Cite

The aim of the investigation is to ground experimentally the mechanism of endovenous laser ablation (EVLA), based on laser-induced convective heat transfer from the blood to the vein walls due to its boiling as a dominating process in a complicated mechanism of heat exchange occurring in endovasal laser manipulations.Materials and Methods. In experimental modeling of EVLA, fragments of varicose trunks of great suphenous veins, removed by combined phlebectomy, have been used. Laser radiation with 970 nm wavelength and 6 and 7 W power was delivered into the vein through a quartz optical fiber with a flat preblackened (initiated) tip. Pullback velocity was 0.5 mm/s. The surface temperature of the vein was measured during laser radiation using FLIR A600 (Sweden) infrared camera. Denaturation of collagen in the vein wall caused by laser impact was determined by differential scanning calorimetry.Results. Recording the surface temperature dynamics of vein with infrared camera allowed visualization of spot heating of the vein wall by the fluid surrounding the gas-steam bubbles. Temperature saturation in the dynamics of heating the media under study has been established to exist, being one of the characteristic features of the first-order phase transition. The degree of collagen denaturation in the venous wall specimens at 6 and 7 W amounted to 87±5 and 97±3%, respectively.Conclusion. Bubble boiling of blood in the veins, providing fast and efficient heat transfer from the heated tip of the quartz optical fiber to the vein walls, has been experimentally confirmed. For successful performing of the EVLA, the fiber traction must be started at the moment of blood boiling; at lower laser powers the fiber must be held for a longer period. In clinical EVLA procedures less powerful and safer laser devices can be used, reducing the risk of post-treatment complications.

show abstract

“…A tumescent fluid is usually inserted to anesthetize the nerves surrounding the vein and to compress the vein. The laser light heats up the vein by a variety of heat transfer mechanisms: absorption in blood and vein tissue, conduction, convection and boiling; see Malskat et al [9]. Heat is transferred towards the vein wall and causes the vein to be irreversibly injured.…”

Section: Introductionmentioning

confidence: 99%

Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

Boer

Oliveira

Geld

et al. 2017

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

a b s t r a c tMotion of a moving laser light heat source in a confined volume has important applications such as in endovenous laser ablation (EVLA) of varicose veins. This light heats up the fluid and the wall volume by absorption and heat conduction. The present study compares the flow and temperature fields in a horizontal tube of 4 mm inner diameter in three idealizations of the EVLA procedure: water with a bare fiber tip, water with a carbonized layer on the fiber tip, and blood. Without boiling, the convection patterns in water and blood are similar and Grashof numbers are high enough to guarantee buoyancy induced flow and axial mixing, while preserving some stratification. A carbonized layer at the fiber tip promotes boiling in water at moderate laser powers. Boiling bubbles in water rapidly detach from the tip, with or without a carbonized layer, and promote mixing and a locally homogeneous temperature field. At 15 W laser power and 4 mm/s pullback speed in blood, a gas bubble may be formed that sticks at the fiber tip, causing strong local heating and possibly fiber damage.

show abstract

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

Cited by 76 publications

References 35 publications

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

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

Contribution of Laser-Induced Gas-Vapor-Liquid Dynamics to the Mechanism of Endovenous Laser Ablation

Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

Contact Info

Product

Resources

About