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

Whiteley, Mark S; Cross, Amy C.; Whiteley, Victoria C.

doi:10.1007/s10103-021-03449-0

Cited by 13 publications

(17 citation statements)

References 40 publications

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“…However, we have previously validated our porcine liver model [5][6][7] and have used it so investigate the effects of RFA and EVLA previously. 19 In conclusion, although LEED is confirmed as a good measure for EVTA, it ignores the effects of time in the rate of application of the energy to the tissue. We have shown that the rate of application of energy has a significant biological effect.…”

Section: Discussionmentioning

confidence: 87%

“…As stated above, we used the validated porcine liver model, [5][6][7] and followed a previously published protocol for measuring thermal spread, carbonisation and the blinding of two observers. 10 Briefly, fresh porcine liver obtained from a local butcher and brought to room temperature (21°C) prior to the experiment. A RFiTT ProCurve catheter (Celon-Olympus, Hamburg, Germany) was placed on the surface of the porcine liver.…”

Section: Methodsmentioning

confidence: 99%

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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.

Nielsen¹,

Croucher²,

Muschamp³

et al. 2022

Preprint

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Introduction: Endovenous thermal ablation (EVTA) is the first line treatment of symptomatic truncal venous reflux. Linear Endovenous Energy Density (LEED) is the measure of energy used per cm of treated vein. The rate of application of energy influences thermal spread and tissue damage. However, time is absent from LEED. The aim of this study was to test the effect of time during EVTA in a validated in-vitro model.Methods: We used a bipolar radofrequency catheter and the previously validated porcine liver model to assess any thermal effects. We used combinations of power and pullback speeds giving LEEDs of 40, 60, 80 and 100 J/cm. High-resolution digital images of the ablation tracts were taken. Each setting was repeated 5 times. Thermal spread was measured using digital measuring software, tissue carbonisation assessed by a defined scale and any device-tissue sticking during treatment was recorded.Results: LEED was significantly positively correlated to thermal spread (r(20) = .86, P < .00001) and carbonisation of the tissue (r(24) = .82, p < .00001). Power was significantly correlated with carbonisation (r(24) = .50, p = .009) but not with thermal spread (r(20) = .34, p = .121). Pullback had no significant correlations with thermal spread or carbonisation. Catheter sticking was only found when the power was >= 15 W or the LEED was >= 80 J/cm.Conclusion: LEED is a good measure of EVTA but does not take into account the time of energy application to tissue. Power, which does include time, has a significant correlation with tissue carbonisation, and is also important in device-tissue sticking. Pullback has no significant correlation to any tissue effects. Quoting the LEED alone in reporting EVTA is inadequate. It is essential to include the power used when LEED is quoted.

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Section: Discussionmentioning

confidence: 87%

Section: Methodsmentioning

confidence: 99%

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.

Nielsen¹,

Croucher²,

Muschamp³

et al. 2022

Preprint

View full text Add to dashboard Cite

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“…However, we have previously validated our porcine liver model [5][6][7] and, as above, have used it to investigate the effects of RFA, EVLA and EMWA previously. 10,18 In conclusion, although LEED is confirmed as a good measure for EVTA, it ignores the effects of time in the rate of application of the energy to the tissue. We have shown that the rate of application of energy (ie: the power) has a significant biological effect.…”

Section: Discussionmentioning

confidence: 90%

“…As stated above, we used the validated porcine liver model, [5][6][7] and followed a previously published protocol for measuring thermal spread, carbonisation and the blinding of two observers. 10 Briefly, fresh porcine liver was obtained from a local butcher and brought to room temperature (21°C) prior to the experiment. A RFiTT ProCurve catheter (Celon-Olympus, Hamburg, Germany) was placed on the surface of the porcine liver.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2023

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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.

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“…EVTA requires transmural death of the vein wall for successful long-term ablation by fibrosis. 15,16 The porcine liver model, with its ability to measure thermal spread from an EVTA device, has proven very useful in assessing such devices, both RFA and EVLA, 10,13,14 and has been shown to correlate well both histologically with ex-vivo great saphenous vein 11 as well as with clinical results. 12 As such, we have produced a table of parameters that doctors might refer to when using the ECO EMWA device to attain an equivalent treatment they would achieve with their preferred setting with the Vari-lase 1470nm radial fibre.…”

Section: Discussionmentioning

confidence: 99%

Defining the parameters for endovenous microwave ablation to achieve equivalence with endovenous laser ablation, using the porcine liver model.

Bachetta¹,

Cheung²,

Moore³

et al. 2022

Preprint

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ABSTRACT Aims: Endovenous microwave ablation (EMWA) is a relatively new catheter-based 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. Therefore, we aimed to define the parameters for EMWA, which give the same tissue ablation as EVLA, using the previously validated porcine liver model. Methods: EVLA (1470nm and 600micron radial fibre) treatments were performed at 6W, 8W and 10W, at each pullback speed of 6, 7, 8 and 9 s/cm, giving a range of Linear Endovenous Energy Densities (LEEDs) between 36 – 90 J/cm. We repeated each combination of power and pullback five times. Following a preliminary screening process to identify parameters that gave similar results, we used EMWA in the same model. Powers of 35-75W and pullback speeds of 4-9 s/cm were used (LEEDs 140-675 J/cm). Ablation tracts from both devices were analysed by two blinded observers, noting thermal spread and carbonisation. Results: For each of the commonly used parameters for EVLA, we identified a range of power and pullback parameters for EMWA that produced similar tissue ablation in the porcine liver model. To keep the pullback speeds within the usual range, we used powers of 35-75W 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 validated porcine liver model to commonly used parameters and LEEDs for EVLA. 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.

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

Cited by 13 publications

References 40 publications

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.

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.

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

Defining the parameters for endovenous microwave ablation to achieve equivalence with endovenous laser ablation, using the porcine liver model.

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